Science.gov

Sample records for transport number measurements

  1. Measurement of Li/sup +/ ion transport numbers in PEO-LiX complexes. Technical report No. 16, 15 July 1985-January 1988

    SciTech Connect

    Munshi, M.Z.; Owens, B.B.; Nguyen, S.

    1988-03-01

    Lithium-ion conducting-polymer materials are being intensively investigated in a number of research laboratories because of their potential use as solid electrolytes in high-energy-density solid-state lithium batteries. The most-widely used polymer were based on polyethylene oxide (PEO). The conduction mechanism in these polymer electrolytes has generally been assumed to be due to Li(+)ion transport from one lone pair site to another along the helical PEO strands. However, recent studies have shown that the Li(+) transport number is less than unity. The transport number for Li(+) ions in PEO-LiX complexes was measured using a potentiostatic polarization technique. The results indicate that the Li(+) ion transport is strongly influenced by the salt concentration and the type of counter ions.

  2. Measuring Distance of Fuzzy Numbers by Trapezoidal Fuzzy Numbers

    NASA Astrophysics Data System (ADS)

    Hajjari, Tayebeh

    2010-11-01

    Fuzzy numbers and more generally linguistic values are approximate assessments, given by experts and accepted by decision-makers when obtaining value that is more accurate is impossible or unnecessary. Distance between two fuzzy numbers plays an important role in linguistic decision-making. It is reasonable to define a fuzzy distance between fuzzy objects. To achieve this aim, the researcher presents a new distance measure for fuzzy numbers by means of improved centroid distance method. The metric properties are also studied. The advantage is the calculation of the proposed method is far simple than previous approaches.

  3. Transportation optimization with fuzzy trapezoidal numbers based on possibility theory.

    PubMed

    He, Dayi; Li, Ran; Huang, Qi; Lei, Ping

    2014-01-01

    In this paper, a parametric method is introduced to solve fuzzy transportation problem. Considering that parameters of transportation problem have uncertainties, this paper develops a generalized fuzzy transportation problem with fuzzy supply, demand and cost. For simplicity, these parameters are assumed to be fuzzy trapezoidal numbers. Based on possibility theory and consistent with decision-makers' subjectiveness and practical requirements, the fuzzy transportation problem is transformed to a crisp linear transportation problem by defuzzifying fuzzy constraints and objectives with application of fractile and modality approach. Finally, a numerical example is provided to exemplify the application of fuzzy transportation programming and to verify the validity of the proposed methods. PMID:25137239

  4. Transportation Optimization with Fuzzy Trapezoidal Numbers Based on Possibility Theory

    PubMed Central

    He, Dayi; Li, Ran; Huang, Qi; Lei, Ping

    2014-01-01

    In this paper, a parametric method is introduced to solve fuzzy transportation problem. Considering that parameters of transportation problem have uncertainties, this paper develops a generalized fuzzy transportation problem with fuzzy supply, demand and cost. For simplicity, these parameters are assumed to be fuzzy trapezoidal numbers. Based on possibility theory and consistent with decision-makers' subjectiveness and practical requirements, the fuzzy transportation problem is transformed to a crisp linear transportation problem by defuzzifying fuzzy constraints and objectives with application of fractile and modality approach. Finally, a numerical example is provided to exemplify the application of fuzzy transportation programming and to verify the validity of the proposed methods. PMID:25137239

  5. Off-Design Reynolds Number Effects for a Supersonic Transport

    NASA Technical Reports Server (NTRS)

    Owens, Lewis R.; Wahls, Richard A.; Rivers, S. Melissa

    2005-01-01

    A high Reynolds number wind tunnel test was conducted to assess Reynolds number effects on the aerodynamic performance characteristics of a realistic, second-generation supersonic transport concept. The tests included longitudinal studies at transonic and low-speed, high-lift conditions across a range of chord Reynolds numbers (8 million to 120 million). Results presented focus on Reynolds number and static aeroelastic sensitivities at Mach 0.30 and 0.90 for a configuration without a tail. Static aeroelastic effects, which mask Reynolds number effects, were observed. Reynolds number effects were generally small and the drag data followed established trends of skin friction as a function of Reynolds number. A more nose-down pitching moment was produced as Reynolds number increased because of an outward movement of the inboard leading-edge separation at constant angles of attack. This study extends the existing Reynolds number database for supersonic transports operating at off-design conditions.

  6. Phylogenetic diversity measures based on Hill numbers

    PubMed Central

    Chao, Anne; Chiu, Chun-Huo; Jost, Lou

    2010-01-01

    We propose a parametric class of phylogenetic diversity (PD) measures that are sensitive to both species abundance and species taxonomic or phylogenetic distances. This work extends the conventional parametric species-neutral approach (based on ‘effective number of species’ or Hill numbers) to take into account species relatedness, and also generalizes the traditional phylogenetic approach (based on ‘total phylogenetic length’) to incorporate species abundances. The proposed measure quantifies ‘the mean effective number of species’ over any time interval of interest, or the ‘effective number of maximally distinct lineages’ over that time interval. The product of the measure and the interval length quantifies the ‘branch diversity’ of the phylogenetic tree during that interval. The new measures generalize and unify many existing measures and lead to a natural definition of taxonomic diversity as a special case. The replication principle (or doubling property), an important requirement for species-neutral diversity, is generalized to PD. The widely used Rao's quadratic entropy and the phylogenetic entropy do not satisfy this essential property, but a simple transformation converts each to our measures, which do satisfy the property. The proposed approach is applied to forest data for interpreting the effects of thinning. PMID:20980309

  7. Measurement of nonvolatile particle number size distribution

    NASA Astrophysics Data System (ADS)

    Gkatzelis, G. I.; Papanastasiou, D. K.; Florou, K.; Kaltsonoudis, C.; Louvaris, E.; Pandis, S. N.

    2016-01-01

    An experimental methodology was developed to measure the nonvolatile particle number concentration using a thermodenuder (TD). The TD was coupled with a high-resolution time-of-flight aerosol mass spectrometer, measuring the chemical composition and mass size distribution of the submicrometer aerosol and a scanning mobility particle sizer (SMPS) that provided the number size distribution of the aerosol in the range from 10 to 500 nm. The method was evaluated with a set of smog chamber experiments and achieved almost complete evaporation (> 98 %) of secondary organic as well as freshly nucleated particles, using a TD temperature of 400 °C and a centerline residence time of 15 s. This experimental approach was applied in a winter field campaign in Athens and provided a direct measurement of number concentration and size distribution for particles emitted from major pollution sources. During periods in which the contribution of biomass burning sources was dominant, more than 80 % of particle number concentration remained after passing through the thermodenuder, suggesting that nearly all biomass burning particles had a nonvolatile core. These remaining particles consisted mostly of black carbon (60 % mass contribution) and organic aerosol (OA; 40 %). Organics that had not evaporated through the TD were mostly biomass burning OA (BBOA) and oxygenated OA (OOA) as determined from AMS source apportionment analysis. For periods during which traffic contribution was dominant 50-60 % of the particles had a nonvolatile core while the rest evaporated at 400 °C. The remaining particle mass consisted mostly of black carbon with an 80 % contribution, while OA was responsible for another 15-20 %. Organics were mostly hydrocarbon-like OA (HOA) and OOA. These results suggest that even at 400 °C some fraction of the OA does not evaporate from particles emitted from common combustion processes, such as biomass burning and car engines, indicating that a fraction of this type of OA is of extremely low volatility.

  8. Reynolds Number Effects on a Supersonic Transport at Transonic Conditions

    NASA Technical Reports Server (NTRS)

    Wahls, R. N.; Owens, L. R.; Rivers, S. M. B.

    2001-01-01

    A High Speed Civil Transport configuration was tested in the National Transonic Facility at the NASA Langley Research Center as part of NASA's High Speed Research Program. The primary purposes of the tests were to assess Reynolds number scale effects and the high Reynolds number aerodynamic characteristics of a realistic, second generation supersonic transport while providing data for the assessment of computational methods. The tests included longitudinal and lateral/directional studies at low speed high-lift and transonic conditions across a range of Reynolds numbers from that available in conventional wind tunnels to near flight conditions. Results are presented which focus on both the Reynolds number and static aeroelastic sensitivities of longitudinal characteristics at Mach 0.90 for a configuration without an empennage.

  9. A numbers game underpins cytoplasmic mRNA transport.

    PubMed

    Doyle, Michael; Kiebler, Michael A

    2012-04-01

    Microtubule-based mRNA transport participates in the establishment of cell asymmetries. An in vitro reconstitution assay demonstrates that localization signals present in an mRNA influence motor copy number on single RNA molecule cargoes, ultimately leading to highly polarized distributions of transcripts. PMID:22469827

  10. Transport Measurements on Superconducting Nanowires

    NASA Astrophysics Data System (ADS)

    Kurtz, J. S.; Tian, M.; Garcia, R.; Mallouk, T. E.; Mayer, T. S.; Liu, Y.; Chan, M. H. W.

    2003-03-01

    High quality, single-crystal nanowires of various elemental metals and superconductors have been fabricated by electro-deposition into porous alumina and polycarbonate membranes. We report here recent magneto-transport measurements at low temperatures on such superconducting Sn nanowires with diameters smaller than the bulk coherence length and penetration depth. These wires allow an investigation of one-dimensional superconductivity in the regime of very low disorder. Transport properties were measured for wires of various diameters in a dilution refrigerator under magnetic fields up to 9 Tesla. Superconducting transitions were observed, and deviations from bulk, 3D behavior such as low-temperature resistive tails and high critical fields will be presented and discussed. This work is supported by NSF MRSEC Grants DMR 0080019 and DMR 0213623.

  11. Sediment transport measurements: Chapter 5

    USGS Publications Warehouse

    Diplas, P.; Kuhnle, R.; Gray, J.; Glysson, D.; Edwards, T.

    2008-01-01

    Sediment erosion, transport, and deposition in fluvial systems are complex processes that are treated in detail in other sections of this book. Development of methods suitable for the collection of data that contribute to understanding these processes is a still-evolving science. Sediment and ancillary data are fundamental requirements for the proper management of river systems, including the design of structures, the determination of aspects of stream behavior, ascertaining the probable effect of removing an existing structure, estimation of bulk erosion, transport, and sediment delivery to the oceans, ascertaining the long-term usefulness of reservoirs and other public works, tracking movement of solid-phase contaminants, restoration of degraded or otherwise modified streams, and assistance in the calibration and validation of numerical models. This chapter presents techniques for measuring bed-material properties and suspended and bed-load discharges. Well-established and relatively recent, yet adequately tested, sampling equipment and methodologies, with designs that are guided by sound physical and statistical principles, are described. Where appropriate, the theory behind the development of the equipment and guidelines for its use are presented.

  12. Nonlocal electron transport in magnetized plasmas with arbitrary atomic number

    SciTech Connect

    Bennaceur-Doumaz, D.; Bendib, A.

    2006-09-15

    The numerical solution of the steady-state electron Fokker-Planck equation perturbed with respect to a global equilibrium is presented in magnetized plasmas with arbitrary atomic number Z. The magnetic field is assumed to be constant and the electron-electron collisions are described by the Landau collision operator. The solution is derived in the Fourier space and in the framework of the diffusive approximation which captures the spatial nonlocal effects. The transport coefficients are deduced and used to close a complete set of nonlocal electron fluid equations. This work improves the results of A. Bendib et al. [Phys. Plasmas 9, 1555 (2002)] and of A. V. Brantov et al. [Phys. Plasmas 10, 4633 (2003)] restricted to the local and nonlocal high-Z plasma approximations, respectively. The influence of the magnetic field on the nonlocal effects is discussed. We propose also accurate numerical fits of the relevant transport coefficients with respect to the collisionality parameter {lambda}{sub ei}/L and the atomic number Z, where L is the typical scale length and {lambda}{sub ei} is the electron-ion mean-free-path.

  13. Electroosmosis in Membranes: Effects of Unstirred Layers and Transport Numbers

    PubMed Central

    Barry, P. H.; Hope, A. B.

    1969-01-01

    When a current is passed through a membrane system, differences in transport numbers between the membrane and the adjacent solutions will, in general, result in depletion and enhancement of concentrations at the membrane-solution interfaces. This will be balanced by diffusion back into the bulk solution, diffusion of solute back across the membrane itself, and osmosis resulting from these local concentration gradients. The two main results of such a phenomenon are (1) that there is a current-induced volume flow, which may be mistaken for electroosmosis, and (2) that there will generally develop transient changes in potential difference (PD) across membranes during and after the passage of current through them. PMID:5786317

  14. Reynolds number influences on turbulent boundary layer momentum transport

    NASA Astrophysics Data System (ADS)

    Priyadarshana, Paththage A.

    There are many engineering applications at Reynolds numbers orders of magnitude higher than existing turbulent boundary layer studies. Currently, the mechanisms for turbulent transport and the Reynolds number dependence of these mechanisms are not well understood. This dissertation presents Reynolds number influences on velocity and vorticity statistics, Reynolds shear stress, and velocity-vorticity correlations for turbulent boundary layers. Well resolved hot-wire data for this study were acquired in the atmospheric surface layer at the SLTEST facility in western Utah. It is shown that during near neutral thermal stability, the flow behaves as a canonical zero pressure gradient turbulent boundary layer, in which the Reynolds number based on momentum thickness, Rtheta, is approximately 2 x 106. The present study also provides information regarding the effects of wall roughness over a limited range of roughness. It is observed that with increasing Rtheta, the inner normalized streamwise intensity increases. This statistic is less sensitive to wall roughness away from the roughness sublayer. In contrast, the inner normalized wall normal intensity is less sensitive to the variation of Rtheta, and it is significantly sensitive to wall roughness. Outside the viscous sublayer, the inner normalized vorticity intensity is less sensitive to both Rtheta and roughness. A primary observation of the Reynolds stress study is that the predominant motions underlying the Reynolds shear stress undergo a significant shift from large to intermediate scales as Rtheta becomes large, irrespective of surface roughness. Quadrant analysis shows that types of motions contributing to the Reynolds stress change significantly at comparable wall normal locations with increasing Rtheta. The mean wall normal gradients of the Reynolds shear stress and the turbulent kinetic energy have direct connections to the transport mechanisms of the turbulent boundary layer. These gradients can be expressed in terms of velocity-vorticity correlations. In this dissertation, voz and uoz correlations are presented. Here, u and v are the streamwise and the wall normal velocities, respectively, and oz is the spanwise vorticity. It is observed that voz correlations exhibit considerable sensitivity to Rtheta as well as to wall roughness. Conversely, uoz correlations are relatively less sensitive to both Rtheta and wall roughness.

  15. Constituent quark scaling violation due to baryon number transport

    SciTech Connect

    Dunlop J. C.; Lisa, M.A., Sorensen, P.

    2011-10-31

    In ultrarelativistic heavy-ion collisions at {radical}s{sub NN} {approx} 200 GeV, the azimuthal emission anisotropy of hadrons with low and intermediate transverse momentum (p{sub T} {approx}< 4 GeV/c) displays an intriguing scaling. In particular, the baryon (meson) emission patterns are consistent with a scenario in which a bulk medium of flowing quarks coalesces into three-quark (two-quark) 'bags.' While a full understanding of this number-of-constituent-quark (NCQ) scaling remains elusive, it is suggestive of a thermalized bulk system characterized by colored dynamical degrees of freedom - a quark-gluon plasma (QGP). In this scenario, one expects the scaling to break down as the central energy density is reduced below the QGP formation threshold; for this reason, NCQ-scaling violation searches are of interest in the energy scan program at the Relativistic Heavy Ion Collider. However, as {radical}s{sub NN} is reduced, it is not only the initial energy density that changes; there is also an increase in the net baryon number at midrapidity, as stopping transports entrance-channel partons to midrapidity. This phenomenon can result in violations of simple NCQ scaling. Still in the context of the quark coalescence model, we describe a specific pattern for the breakdown of the scaling that includes different flow strengths for particles and their antipartners. Related complications in the search for recently suggested exotic phenomena are also discussed.

  16. Homodyne measurement of the average photon number

    SciTech Connect

    Webb, J. G.; Huntington, E. H.; Ralph, T. C.

    2006-03-15

    We describe a scheme for measurement of the mean photon flux at an arbitrary optical sideband frequency using homodyne detection. Experimental implementation of the technique requires an acousto-optic modulator in addition to the homodyne detector, and does not require phase locking. The technique exhibits polarization and frequency and spatial mode selectivity, as well as much improved speed, resolution, and dynamic range when compared to linear photodetectors and avalanche photodiodes, with potential application to quantum-state tomography and information encoding using an optical frequency basis. Experimental data also support a quantum-mechanical description of vacuum noise.

  17. Hyperreactive platelet phenotypes: Relationship to altered serotonin transporter number, transport kinetics and intrinsic response to adrenergic co-stimulation

    PubMed Central

    Berger, Jeffrey S.; Becker, Richard C.; Kuhn, Cynthia; Helms, Michael J.; Ortel, Thomas L.; Williams, Redford

    2013-01-01

    Summary The mechanism underlying a hyperreactive platelet phenotype remains unknown. Since serotonin has been shown to influence platelet biology and atherothrombosis, we sought to investigate the association of platelet serotonin transporter number, binding affinity, and uptake kinetics to platelet aggregation. A total of 542 healthy volunteers had light transmittance platelet aggregometry measured in response to varying concentrations of epinephrine, serotonin, epinephrine plus serotonin, ADP and collagen. Transporter-dependent serotonin uptake rate was determined (Vmax), as were serotonin transporter number (Bmax) and binding affinity (Kd) using 3H paroxetine binding in a homologous displacement assay, nonlinear regression and validated algorithms for kinetic modeling. Stimulation with submaximal (2 μM) epinephrine concentration elicited a distinct, bimodal pattern of platelet aggregation in this population. In contrast, subjects exhibited minimal aggregation in response to serotonin alone. Co-stimulation with submaximal epinephrine and serotonin induced platelet aggregation to a level beyond that observed with either agonist alone and maintained a bimodal response distribution. Subjects with heightened (>60%) platelet aggregation to both epinephrine alone and epinephrine plus serotonin exhibited increased platelet serotonin uptake, and transporter number and affinity. In a population of healthy subjects, co-stimulation with submaximal concentrations of epinephrine and serotonin identifies a subset of individuals with a hyperreactive platelet aggregation profile that is associated with changes in platelet serotonin function. PMID:23223800

  18. Prandtl-Number Dependence of Heat Transport in Laminar Horizontal Convection

    NASA Astrophysics Data System (ADS)

    Shishkina, Olga; Wagner, Sebastian

    2016-01-01

    We report the Prandtl-number (Pr) and Rayleigh-number (Ra) dependencies of the Reynolds number (Re) and mean convective heat transport, measured by the Nusselt number (Nu), in horizontal convection (HC) systems, where the heat supply and removal are provided exclusively through a lower horizontal surface of a fluid layer. For laminar HC, we find that Re ˜Ra2 /5Pr-4 /5 , Nu ˜Ra1 /5Pr1 /10 with a transition to Re ˜Ra1 /2Pr-1, Nu ˜Ra1 /4Pr0 for large Pr. The results are based on direct numerical simulations for Ra from 3 ×108 to 5 ×1010 and Pr from 0.05 to 50 and are explained by applying the Grossmann-Lohse approach [J. Fluid Mech. 407, 27 (2000)] transferred from the case of Rayleigh-Bénard convection to the case of laminar HC.

  19. Heat transport measurements in turbulent rotating Rayleigh-Benard convection

    SciTech Connect

    Ecke, Robert E; Liu, Yuanming

    2008-01-01

    We present experimental heat transport measurements of turbulent Rayleigh-Benard convection with rotation about a vertical axis. The fluid, water with Prandtl number ({sigma}) about 6, was confined in a cell which had a square cross section of 7.3 cm x 7.3 cm and a height of 9.4 cm. Heat transport was measured for Rayleigh numbers 2 x 10{sup 5} < Ra < 5 x 10{sup 8} and Taylor numbers 0 < Ta < 5 x 10{sup 9}. We show the variation of normalized heat transport, the Nusselt number, at fixed dimensional rotation rate {Omega}{sub D}, at fixed Ra varying Ta, at fixed Ta varying Ra, and at fixed Rossby number Ro. The scaling of heat transport in the range 10{sup 7} to about 10{sup 9} is roughly 0.29 with a Ro dependent coefficient or equivalently is also well fit by a combination of power laws of the form a Ra{sup 1/5} + b Ra{sup 1/3} . The range of Ra is not sufficient to differentiate single power law or combined power law scaling. The overall impact of rotation on heat transport in turbulent convection is assessed.

  20. Children's number-line estimation shows development of measurement skills (not number representations).

    PubMed

    Cohen, Dale J; Sarnecka, Barbara W

    2014-06-01

    Children's understanding of numbers is often assessed using a number-line task, where the child is shown a line labeled with 0 at one end and a higher number (e.g., 100) at the other end. The child is then asked where on the line some intermediate number (e.g., 70) should go. Performance on this task changes predictably during childhood, and this has often been interpreted as evidence of a change in the child's psychological representation of integer quantities. The present article presents theoretical and empirical evidence that the change in number-line performance actually reflects the development of measurement skills used in the task. We compare 2 versions of the number-line task: the bounded version used in the literature and a new, unbounded version. Results indicate that it is only children's performance on the bounded task (which requires subtraction or division) that changes markedly with age. In contrast, children's performance on the unbounded task (which requires only addition) remains fairly constant as they get older. Thus, developmental changes in performance on the traditional bounded number-line task likely reflect the growth of task-specific measurement skills rather than changes in the child's understanding of numerical quantities. PMID:24512172

  1. Fluid transport at low Reynolds number with magnetically actuated artificial cilia.

    PubMed

    Gauger, E M; Downton, M T; Stark, H

    2009-02-01

    By numerical modeling we investigate fluid transport in low-Reynolds-number flow achieved with a special elastic filament or artificIal cilium attached to a planar surface. The filament is made of superparamagnetic particles linked together by DNA double strands. An external magnetic field induces dipolar interactions between the beads of the filament which provides a convenient way of actuating the cilium in a well-controlled manner. The filament has recently been used to successfully construct the first artificial micro-swimmer (R. Dreyfus et al., Nature 437, 862 (2005)). In our numerical study we introduce a measure, which we call pumping performance, to quantify the fluid transport induced by the magnetically actuated cilium and identify an optimum stroke pattern of the filament. It consists of a slow transport stroke and a fast recovery stroke. Our detailed parameter study also reveals that for sufficiently large magnetic fields the artificial cilium is mainly governed by the Mason number that compares frictional to magnetic forces. Initial studies on multi-cilia systems show that the pumping performance is very sensitive to the imposed phase lag between neighboring cilia, i.e., to the details of the initiated metachronal wave. PMID:19030903

  2. Transport-number determination of a protonic ceramic electrolyte membrane via electrode-polarisation correction with the Gorelov method

    NASA Astrophysics Data System (ADS)

    Pérez-Coll, Domingo; Heras-Juaristi, Gemma; Fagg, Duncan P.; Mather, Glenn C.

    2014-01-01

    Analysis of transport numbers is critical for assessing the suitability of an ion-conducting material for a given electrochemical application and the conditions for its employment. In this work, the proton, oxide-ion and electron transport numbers of the candidate protonic ceramic electrolyser and fuel cell material SrZr0.9Y0.1O3-δ (with the addition of 4 mol% ZnO as sintering aid) are measured in wet and dry oxidising atmospheres in the temperature range 700-850 °C. The determination of proton transport numbers is analysed in detail, encompassing the suitability of equivalent circuits in different conditions and the inclusion of an external parallel resistance for the correction of electrode-polarisation effects (Gorelov method). It is confirmed that transport numbers are highly inaccurate if no polarisation correction is applied. In dry oxidising conditions oxide-ion transport numbers, to, lie in the range 0.63-0.78. The conductivity in wet oxidising conditions is dominated by protons and an electronic component, with the proton transport number increasing from 0.79 to 0.88 with increasing pH2O in the range 1.1 × 10-3 ≤ pH2O ≤ 1.27 × 10-2 atm at 700 °C.

  3. Meanings for Fraction as Number-Measure by Exploring the Number Line

    ERIC Educational Resources Information Center

    Psycharis, Giorgos; Latsi, Maria; Kynigos, Chronis

    2009-01-01

    This paper reports on a case-study design experiment in the domain of fraction as number-measure. We designed and implemented a set of exploratory tasks concerning comparison and ordering of fractions as well as operations with fractions. Two groups of 12-year-old students worked collaboratively using paper and pencil as well as a specially

  4. Florida current volume transports from voltage measurements.

    PubMed

    Larsen, J C; Sanford, T B

    1985-01-18

    The volume transport of the Florida Current is determined from the motionally induced voltage difference between Florida and Grand Bahama Island. Simultaneous measurements of potential differences and of volume transport by velocity profiling have a correlation of 0.97. The calibration factor is 25+/- 0.7 sverdrups per volt, and the root-mean-square discrepancy is 0.7 sverdrup. The induced voltage is about one-half the open-circuit value, implying that the conductance of the sediments and lithosphere is about equal to that of the water column. PMID:17742101

  5. Florida Current volume transports from voltage measurements

    SciTech Connect

    Larsen, J.C.; Sanford, T.B.

    1985-01-18

    The volume transport of the Florida Current is determined from the motionally induced voltage difference between Florida and Grand Bahama Island. Simultaneous measurements of potential differences and of volume transport by velocity profiling have a correlation of 0.97. The calibration factor is 25 +/- 0.7 sverdrups per volt, and the root-mean square discrepancy is 0.7 sverdrup. The induced voltage is about one-half the open-circuit value, implying that the conductance of the sediments and lithosphere is about equal to that of the water column. 11 references, 2 figures.

  6. Prandtl-Number Dependence of Heat Transport in Laminar Horizontal Convection.

    PubMed

    Shishkina, Olga; Wagner, Sebastian

    2016-01-15

    We report the Prandtl-number (Pr) and Rayleigh-number (Ra) dependencies of the Reynolds number (Re) and mean convective heat transport, measured by the Nusselt number (Nu), in horizontal convection (HC) systems, where the heat supply and removal are provided exclusively through a lower horizontal surface of a fluid layer. For laminar HC, we find that Re∼Ra^{2/5}Pr^{-4/5}, Nu∼Ra^{1/5}Pr^{1/10} with a transition to Re∼Ra^{1/2}Pr^{-1}, Nu∼Ra^{1/4}Pr^{0} for large Pr. The results are based on direct numerical simulations for Ra from 3×10^{8} to 5×10^{10} and Pr from 0.05 to 50 and are explained by applying the Grossmann-Lohse approach [J. Fluid Mech. 407, 27 (2000)] transferred from the case of Rayleigh-Bénard convection to the case of laminar HC. PMID:26824542

  7. Transportable setup for amplifier phase fidelity measurements

    NASA Astrophysics Data System (ADS)

    Tröbs, M.; Bogan, C.; Barke, S.; Kühn, G.; Reiche, J.; Heinzel, G.; Danzmann, K.

    2015-05-01

    One possible laser source for the Laser Interferometer Space Antenna (LISA) consists of an Ytterbium-doped fiber amplifier originally developed for inter-satellite communication, seeded by the laser used for the technology demonstrator mission LISA Pathfinder. LISA needs to transmit clock information between its three spacecraft to correct for phase noise between the clocks on the individual spacecraft. For this purpose phase modulation sidebands at GHz frequencies will be imprinted on the laser beams between spacecraft. Differential phase noise between the carrier and a sideband introduced within the optical chain must be very low. We report on a transportable setup to measure the phase fidelity of optical amplifiers.

  8. Measurement of non-volatile particle number size distribution

    NASA Astrophysics Data System (ADS)

    Gkatzelis, G. I.; Papanastasiou, D. K.; Florou, K.; Kaltsonoudis, C.; Louvaris, E.; Pandis, S. N.

    2015-06-01

    An experimental methodology was developed to measure the non-volatile particle number concentration using a thermodenuder (TD). The TD was coupled with a high-resolution time-of-flight aerosol mass spectrometer, measuring the chemical composition and mass size distribution of the submicrometer aerosol and a scanning mobility particle sizer (SMPS) that provided the number size distribution of the aerosol in the range from 10 to 500 nm. The method was evaluated with a set of smog chamber experiments and achieved almost complete evaporation (> 98 %) of secondary organic as well as freshly nucleated particles, using a TD temperature of 400 °C and a centerline residence time of 15 s. This experimental approach was applied in a winter field campaign in Athens and provided a direct measurement of number concentration and size distribution for particles emitted from major pollution sources. During periods in which the contribution of biomass burning sources was dominant, more than 80 % of particle number concentration remained after passing through the thermodenuder, suggesting that nearly all biomass burning particles had a non-volatile core. These remaining particles consisted mostly of black carbon (60 % mass contribution) and organic aerosol, OA (40 %). Organics that had not evaporated through the TD were mostly biomass burning OA (BBOA) and oxygenated OA (OOA) as determined from AMS source apportionment analysis. For periods during which traffic contribution was dominant 50-60 % of the particles had a non-volatile core while the rest evaporated at 400 °C. The remaining particle mass consisted mostly of black carbon (BC) with an 80 % contribution, while OA was responsible for another 15-20 %. Organics were mostly hydrocarbon-like OA (HOA) and OOA. These results suggest that even at 400 °C some fraction of the OA does not evaporate from particles emitted from common combustion processes, such as biomass burning and car engines, indicating that a fraction of this type of OA is of extremely low volatility.

  9. First measurements of aerosol optical depth and Angstrom exponent number from AERONET's Kuching site

    NASA Astrophysics Data System (ADS)

    Salinas, Santo V.; Chew, Boon N.; Mohamad, M.; Mahmud, M.; Liew, Soo C.

    2013-10-01

    We report our first measurements, over the 2011 dry season period, of aerosol optical depth, Angstrom exponent number and its fine mode counterpart obtained from photometric measurements at AERONET's newest site located at the city of Kuching, Sarawak, East Malaysia. This site was set up as part of the collaborative efforts of the Seven South East Asian Studies (7SEAS) regional aerosol measurements initiative. Located at the converging zone between peninsular Malaysia and the land masses of Sumatra, Borneo, Java and Sulawesi, this site is expected to provide first hand evidence about the physical and optical characteristics of the regional aerosol environment, specially during the biomass burning months. Moreover, given its relative proximity to our Singapore radiation measurement super-site, Kuching is expected to provide further insight on aerosol transport pathways caused by seasonal winds transporting smoke to other parts of the maritime continent and the South Asia region.

  10. Experimental determination of the transport number of water in Nafion 117 membrane

    SciTech Connect

    Fuller, T.F.; Newman, J. . Dept. of Chemical Engineering)

    1992-05-01

    The transport number of water in Nafion 117 membrane over a wide range of water contents is determined experimentally using a concentration cell. The transport number of water, the ratio f[sup m][sub o]/Z[sub o], is about 1.4 for a membrane equilibrated with saturated water vapor at 25[degrees]C, decreases slowly as the membrane is dehydrated, and falls sharply toward zero as the concentration of water approaches zero. In this paper, the relationship between the transference number, the transport number, and the electro-osmotic drag coefficient is presented, and their relevance to water management is solid-polymer-electrolyte fuel cells is discussed. Results are compared with other data available in the literature and with the theoretical maximum.

  11. VARIABILITY IN MEASURED BEDLOAD-TRANSPORT RATES.

    USGS Publications Warehouse

    Carey, William P.

    1985-01-01

    During a four-day period of nearly constant water discharge, four sets of consecutively collected bedload samples, ranging from 43 to 120 samples, were obtained at the same cross channel location using a standard 65-pound Helley-Smith bedload sampler. When the measured transport rates are converted to dimensionless rates and plotted as cumulative frequency distributions, they show good agreement with a theoretical probability distribution function of rates derived for the case of ripples on dunes. The distributions show that during constant water discharge individual measured rates at a fixed point vary from near zero to four times the mean rate, and 60 percent of the sampled rates will be less than the mean.

  12. Transport measurement of the orbital Kondo effect with ultracold atoms

    NASA Astrophysics Data System (ADS)

    Nishida, Yusuke

    2016-01-01

    The Kondo effect in condensed-matter systems manifests itself most sharply in their transport measurements. Here we propose an analogous transport signature of the orbital Kondo effect realized with ultracold atoms. Our system consists of imbalanced Fermi seas of two components of fermions and an impurity atom of different species which is confined by an isotropic potential. We first apply a π /2 pulse to transform two components of fermions into two superposition states. Their interactions with the impurity atom then cause a "transport" of fermions from majority to minority superposition states, whose numbers can be measured after applying another 3 π /2 pulse. In particular, when the interaction of one component of fermions with the impurity atom is tuned close to a confinement-induced p -wave or higher partial-wave resonance, the resulting conductance is shown to exhibit the Kondo signature, i.e., universal logarithmic growth by lowering the temperature. The proposed transport measurement will thus provide a clear evidence of the orbital Kondo effect accessible in ultracold atom experiments and pave the way for developing new insights into Kondo physics.

  13. Turbulence measurements in high Reynolds number boundary layers

    NASA Astrophysics Data System (ADS)

    Vallikivi, Margit; Smits, Alexander

    2013-11-01

    Measurements are conducted in zero pressure gradient turbulent boundary layers for Reynolds numbers from Reθ = 9,000 to 225,000. The experiments were performed in the High Reynolds number Test Facility (HRTF) at Princeton University, which uses compressed air as the working fluid. Nano-Scale Thermal Anemometry Probes (NSTAPs) are used to acquire data with very high spatial and temporal precision. These new data are used to study the scaling behavior of the streamwise velocity fluctuations in the boundary layer and make comparisons with the scaling of other wall-bounded turbulent flows. Supported under ONR Grant N00014-09-1-0263 (program manager Ron Joslin) and NSF Grant CBET-1064257 (program manager Henning Winter).

  14. Effects of Lewis number on turbulent scalar transport and its modelling in turbulent premixed flames

    SciTech Connect

    Chakraborty, Nilanjan; Cant, R.S.

    2009-07-15

    The behaviour of the turbulent scalar flux in premixed flames has been studied using Direct Numerical Simulation (DNS) with emphasis on the effects of Lewis number in the context of Reynolds-averaged closure modelling. A database was obtained from DNS of three-dimensional freely propagating statistically planar turbulent premixed flames with simplified chemistry and a range of global Lewis numbers from 0.34 to 1.2. Under the same initial conditions of turbulence, flames with low Lewis numbers are found to exhibit counter-gradient transport, whereas flames with higher Lewis numbers tend to exhibit gradient transport. The Reynolds-averaged transport equation for the turbulent scalar flux is analysed in detail and the performance of existing models for the unclosed terms is assessed with respect to corresponding quantities extracted from DNS data. Based on this assessment, existing models which are able to address the effects of non-unity Lewis number on turbulent scalar flux transport are identified, and new or modified models are suggested wherever necessary. In this way, a complete set of closure models for the scalar flux transport equation is prescribed for use in Reynolds-Averaged Navier-Stokes simulations. (author)

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

    PubMed

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

    2010-09-01

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

  16. NANONIS TRAMEA - A Quantum Transport Measurement System

    NASA Astrophysics Data System (ADS)

    Kampen, Thorsten; Thissen, Andreas; Schaff, Oliver; Pioda, Alessandro

    Nanonis Tramea is a quantum leap with respect to increased speed for transport measurements taking research onto a new level. Measurements which took several hours in the past can now be done in minutes without compromising signal quality. Tramea uses its fast, high-resolution, high-precision and ultra-low-noise outputs and inputs to generate and acquire up to 20000 data points per second on 24 channels in parallel. This is not only up to 1000 x faster than typical measurement systems but it is also time deterministic with highest precision. Here, the time separation between points is constant so that artefacts caused by unequal point spacings in non-deterministic measurement systems are avoided. The emphasis here is the real-time relation. Tramea comes with a built-in interface which allows for control of the instruments' basic functions from any programming environment. For users requiring more functionality and higher speeds a full-featured LabVIEW-based programming interface or scripting module are available as add-on modules. Due to the modularity and flexibility of the hardware and software architecture of Tramea upgrades with standardized add-on modules are possible. Non-standard requests can still be handled by the various programming options.

  17. 40 CFR 51.213 - Transportation control measures.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 2 2011-07-01 2011-07-01 false Transportation control measures. 51.213... Transportation control measures. (a) The plan must contain procedures for obtaining and maintaining data on actual emissions reductions achieved as a result of implementing transportation control measures. (b)...

  18. 40 CFR 51.213 - Transportation control measures.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 2 2012-07-01 2012-07-01 false Transportation control measures. 51.213... Transportation control measures. (a) The plan must contain procedures for obtaining and maintaining data on actual emissions reductions achieved as a result of implementing transportation control measures. (b)...

  19. 40 CFR 51.213 - Transportation control measures.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 2 2010-07-01 2010-07-01 false Transportation control measures. 51.213... Transportation control measures. (a) The plan must contain procedures for obtaining and maintaining data on actual emissions reductions achieved as a result of implementing transportation control measures. (b)...

  20. 40 CFR 51.213 - Transportation control measures.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 2 2014-07-01 2014-07-01 false Transportation control measures. 51.213... Transportation control measures. (a) The plan must contain procedures for obtaining and maintaining data on actual emissions reductions achieved as a result of implementing transportation control measures. (b)...

  1. Automatic trajectory measurement of large numbers of crowded objects

    NASA Astrophysics Data System (ADS)

    Li, Hui; Liu, Ye; Chen, Yan Qiu

    2013-06-01

    Complex motion patterns of natural systems, such as fish schools, bird flocks, and cell groups, have attracted great attention from scientists for years. Trajectory measurement of individuals is vital for quantitative and high-throughput study of their collective behaviors. However, such data are rare mainly due to the challenges of detection and tracking of large numbers of objects with similar visual features and frequent occlusions. We present an automatic and effective framework to measure trajectories of large numbers of crowded oval-shaped objects, such as fish and cells. We first use a novel dual ellipse locator to detect the coarse position of each individual and then propose a variance minimization active contour method to obtain the optimal segmentation results. For tracking, cost matrix of assignment between consecutive frames is trainable via a random forest classifier with many spatial, texture, and shape features. The optimal trajectories are found for the whole image sequence by solving two linear assignment problems. We evaluate the proposed method on many challenging data sets.

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

    NASA Technical Reports Server (NTRS)

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

    2003-01-01

    It is well established that residual flows exist in contained liquid metal processes. In 1-g processing, buoyancy forces often drive these flows and their magnitudes can be substantial. It is also known that residual flows can exist during microgravity processing, and although greatly reduced in magnitude, they can influence the properties of the processed materials. Unfortunately, there are very few techniques to visualize flows in opaque, high temperature liquid metals, and those available are not easily adapted to flight investigation. In this study, a novel technique is developed that uses liquid tin as the model fluid and solid-state electrochemical cells constructed from Yttria-Stabilized Zirconia (YSZ) to establish and measure dissolved oxygen boundary conditions. The melt serves as a common electrode for each of the electrochemical cells in this design, while independent reference electrodes are maintained at the outside surfaces of the electrolyte. By constructing isolated electrochemical cells at various locations along the container walls, oxygen is introduced or extracted by imposing a known electrical potential or passing a given current between the melt and the reference electrode. This programmed titration then establishes a known oxygen concentration boundary condition at the selected electrolyte-melt interface. Using the other cells, the concentration of oxygen at the electrolyte-melt interface is also monitored by measuring the open-circuit potentials developed between the melt and reference electrodes. Thus the electrochemical cells serve to both establish boundary conditions for the passive tracer and sense its path. Rayleigh-Benard convection was used to validate the electrochemical approach to flow visualization. Thus, a numerical characterization of the second critical Rayleigh numbers in liquid tin was conducted for a variety of Cartesian aspect ratios. The extremely low Prandtl number of tin represents the lowest value studied numerically. Additionally, flow field oscillations are visualized and the effect of tilt on convecting systems is quantified. Experimental studies of the effect of convection in liquid tin are presented. Three geometries are studied: (1) double electrochemical cell with vertical concentration gradients; (2) double cell with horizontal concentration gradients; and (3) multiple cells with vertical temperature gradients. The first critical Rayleigh number transition is detected with geometry (1) and it is concluded that current measurements are not as affected by convection as EMF measurements. The system is compared with numerical simulations in geometry (2), and oscillating convection is detected with geometry (3).

  3. Children's Number-Line Estimation Shows Development of Measurement Skills (Not Number Representations)

    ERIC Educational Resources Information Center

    Cohen, Dale J.; Sarnecka, Barbara W.

    2014-01-01

    Children's understanding of numbers is often assessed using a number-line task, where the child is shown a line labeled with 0 at one end and a higher number (e.g., 100) at the other end. The child is then asked where on the line some intermediate number (e.g., 70) should go. Performance on this task changes predictably during childhood, and…

  4. Variation of bedload transport threshold in two Alpine mountain streams inferred from geophone measurements

    NASA Astrophysics Data System (ADS)

    Rickenmann, Dieter; Weninger, Thomas

    2015-04-01

    Geophone measurements are a surrogate technique to monitor bedload transport in mountain streams. The two mountain streams Fischbach and the Ruetz in Western Austria are fed by glacial meltwater and feature regular bedload transport during the summer months. In spring 2008 the so-called Swiss plate geophone system was installed in the two streams. The sites are operated by the Tyrolean water power company (TIWAG), and discharge data are available as well. The geophone sensors record the motion of bedload particles transported over a steel plate mounted flush with the channel bed. Calibration measurements of the geophone system were performed by TIWAG, and they show an approximately linear relation between number of impulses and bedload mass transported over the sensors. For the period 2008 to 2013, the variation in bedload transport with shear stress was analyzed using an exponential form of the Meyer-Peter & Müller equation proposed by Chen (2002). If the dimensionless threshold shear stress at initiation of motion, i.e. the Shields number, is back-calculated from the measured bedload transport rates, the temporal variability in bedload transport efficiency can be reasonably well described by postulating a corresponding temporal variability in the Shields number. The geophone measurements were also used to qualitatively assess the grain size distribution of the transported particles. It is hypothesized that an increase in the Shields number is associated with a coarsening of the surface grain size distribution of the bed material upstream of the measuring site.

  5. Characterization of Lorenz number with Seebeck coefficient measurement

    NASA Astrophysics Data System (ADS)

    Kim, Hyun-Sik; Gibbs, Zachary M.; Tang, Yinglu; Wang, Heng; Snyder, G. Jeffrey

    2015-04-01

    In analyzing zT improvements due to lattice thermal conductivity (κL) reduction, electrical conductivity (σ) and total thermal conductivity (κTotal) are often used to estimate the electronic component of the thermal conductivity (κE) and in turn κL from κL = ˜ κTotal - LσT. The Wiedemann-Franz law, κE = LσT, where L is Lorenz number, is widely used to estimate κE from σ measurements. It is a common practice to treat L as a universal factor with 2.44 × 10-8 WΩK-2 (degenerate limit). However, significant deviations from the degenerate limit (approximately 40% or more for Kane bands) are known to occur for non-degenerate semiconductors where L converges to 1.5 × 10-8 WΩK-2 for acoustic phonon scattering. The decrease in L is correlated with an increase in thermopower (absolute value of Seebeck coefficient (S)). Thus, a first order correction to the degenerate limit of L can be based on the measured thermopower, |S|, independent of temperature or doping. We propose the equation: L = 1 . 5 + exp [" separators=" - /| S | 116 ] (where L is in 10-8 WΩK-2 and S in μV/K) as a satisfactory approximation for L. This equation is accurate within 5% for single parabolic band/acoustic phonon scattering assumption and within 20% for PbSe, PbS, PbTe, Si0.8Ge0.2 where more complexity is introduced, such as non-parabolic Kane bands, multiple bands, and/or alternate scattering mechanisms. The use of this equation for L rather than a constant value (when detailed band structure and scattering mechanism is not known) will significantly improve the estimation of lattice thermal conductivity.

  6. Reynolds Number Effects on a Supersonic Transport at Subsonic High-Lift Conditions (Invited)

    NASA Technical Reports Server (NTRS)

    Owens, L.R.; Wahls, R. A.

    2001-01-01

    A High Speed Civil Transport configuration was tested in the National Transonic Facility at the NASA Langley Research Center as part of NASA's High Speed Research Program. The primary purposes of the tests were to assess Reynolds number scale effects and high Reynolds number aerodynamic characteristics of a realistic, second generation supersonic transport while providing data for the assessment of computational methods. The tests included longitudinal and lateral/directional studies at transonic and low-speed, high-lift conditions across a range of Reynolds numbers from that available in conventional wind tunnels to near flight conditions. Results are presented which focus on Reynolds number and static aeroelastic sensitivities of longitudinal characteristics at Mach 0.30 for a configuration without an empennage. A fundamental change in flow-state occurred between Reynolds numbers of 30 to 40 million, which is characterized by significantly earlier inboard leading-edge separation at the high Reynolds numbers. Force and moment levels change but Reynolds number trends are consistent between the two states.

  7. Measurements of Molecular Mixing in a High Schmidt Number Rayleigh-Taylor Mixing Layer

    SciTech Connect

    Mueschke, N J; Schilling, O; Youngs, D L; Andrews, M

    2007-12-03

    Molecular mixing measurements are performed for a high Schmidt number (Sc {approx} 10{sup 3}), small Atwood number (A {approx} 7.5 x 10{sup -4}) buoyancy-driven turbulent Rayleigh-Taylor mixing layer in a water channel facility. Salt was added to the top stream to create the desired density difference. The degree of molecular mixing was measured as a function of time by monitoring a diffusion-limited chemical reaction between the two fluid streams. The pH of each stream was modified by the addition of acid or alkali such that a local neutralization reaction occurred as the two fluids molecularly mixed. The progress of this neutralization reaction was tracked by the addition of phenolphthalein - a pH-sensitive chemical indicator - to the acidic stream. Accurately calibrated backlit optical techniques were used to measure the average concentration of the colored chemical indicator. Comparisons of chemical product formation for pre-transitional buoyancy- and shear-driven mixing layers are given. It is also shown that experiments performed at different equivalence ratios (acid/alkali concentration) can be combined to obtain a mathematical relationship between the colored product formed and the density variance. This relationship was used to obtain high-fidelity, quantitative measures of the degree of molecular mixing which are independent of probe resolution constraints. The dependence of such mixing parameters on the Schmidt and Reynolds numbers is examined by comparing the current Sc {approx} 10{sup 3} measurements with Sc = 0.7 gas-phase and Pr = 7 liquid-phase measurements. This comparison indicates that the Schmidt number has a large effect on the bulk quantity of mixed fluid at small Reynolds numbers Re{sub h} < 10{sup 3}. At late times, all mixing parameters indicated a greater degree of molecular mixing and a decreased Schmidt number dependence. Implications for the development and quantitative assessment of turbulent transport and mixing models appropriate for Rayleigh?Taylor instability-induced mixing are discussed.

  8. Transport Measurements on Si Nanostructures with Counted Sb Donors

    NASA Astrophysics Data System (ADS)

    Singh, Meenakshi; Bielejec, Edward; Garratt, Elias; Ten Eyck, Gregory; Bishop, Nathaniel; Wendt, Joel; Luhman, Dwight; Carroll, Malcolm; Lilly, Michael

    2014-03-01

    Donor based spin qubits are a promising platform for quantum computing. Single qubits using timed implant of donors have been demonstrated.1 Extending this to multiple qubits requires precise control over the placement and number of donors. Such control can be achieved by using a combination of low-energy heavy-ion implants (to reduce depth straggle), electron-beam lithography (to define position), focused ion beam (to localize implants to one lithographic site) and counting the number of implants with a single ion detector.2 We report transport measurements on MOS quantum dots implanted with 5, 10 and 20 Sb donors using the approach described above. A donor charge transition is identified by a charge offset in the transport characteristics. Correlation between the number of donors and the charge offsets is studied. These results are necessary first steps towards fabricating donor nanostructures for two qubit interactions. This work was performed, in part, at the Center for Integrated Nanotechnologies, a U.S. DOE Office of Basic Energy Sciences user facility. The work was supported by Sandia National Laboratories Directed Research and Development Program. Sandia National Laboratories is a multi-program laboratory operated by Sandia Corporation, a Lockheed-Martin Company, for the U. S. Department of Energy under Contract No. DE-AC04-94AL85000. 1J. J. Pla et al., Nature 496, 334 (2013) 2J. A. Seamons et al., APL 93, 043124 (2008).

  9. TRANSPORT PROPERTY MEASUREMENTS OF HFC-236EA

    EPA Science Inventory

    The report gives results of an evaluation of transport properties of 1,1,1,2,3,3,-hexafluoropropane (HFC-236ea), with liquid viscosity and thermal conductivity being the two main transport properties of interest. In addition, the specific heat and density of refrigerant/lubrican...

  10. Measurement of Hydrocarbon Transport in Bacteria

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Hydrocarbon uptake by bacteria has not been extensively studied, and strong evidence for active transport of hydrocarbons is lacking. The volatile nature of hydrocarbons, their hydrophobicity, and their relatively low aqueous solubilities can complicate transport assays. Here we present a detailed...

  11. Measurement of hydrocarbon transport in bacteria

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Due to the hydrophobic, volatility, and relatively low aqueous solubility of aliphatic and aromatic hydrocarbons, transport of these chemicals by bacteria has not been extensively studied. These issues make transport assays difficult to carry out, and as a result, strong evidence for the active tran...

  12. TRANSPORT PROPERTY MEASUREMENTS OF HFC-236EA

    EPA Science Inventory

    The report gives results of an evaluation of transport properties of 1, 1, 1, 2, 3, 3-hexafluoropropane (HFC-236ea), with liquid viscosity and thermal conductivity being the two main transport properties of interest. In addition, the specific heat and density of refrigerant/lubri...

  13. High-Schmidt-number mass transport mechanisms from a turbulent flow to absorbing sediments

    NASA Astrophysics Data System (ADS)

    Scalo, Carlo; Piomelli, Ugo; Boegman, Leon

    2012-08-01

    We have investigated the mechanisms involved in dissolved oxygen (DO) transfer from a turbulent flow to an underlying organic sediment bed populated with DO-absorbing bacteria. Our numerical study relies on a previously developed and tested computational tool that couples a bio-geochemical model for the sediment layer and large-eddy simulation for transport on the water side. Simulations have been carried out in an open channel configuration for different Reynolds numbers (Reτ = 180-1000), Schmidt numbers (Sc = 400-1000), and bacterial populations (χ* = 100-700 mg l-1). We show that the average oxygen flux across the sediment-water interface (SWI) changes with Reτ and Sc, in good agreement with classic heat-and-mass-transfer parametrizations. Time correlations at the SWI show that intermittent peaks in the wall-shear stress initiate the mass transfer and modulate its distribution in space and time. The diffusive sublayer acts as a de-noising filter with respect to the overlying turbulence; the instantaneous mass flux is not affected by low-amplitude background fluctuations in the wall-shear stress but, on the other hand, it is receptive to energetic and coherent near-wall transport events, in agreement with the surface renewal theory. The three transport processes involved in DO depletion (turbulent transport, molecular transport across the diffusive sublayer, and absorption in the organic sediment layer) exhibit distinct temporal and spatial scales. The rapidly evolving near-wall high-speed streaks transport patches of fluid to the edge of the diffusive sublayer, leaving slowly regenerating elongated patches of positive DO concentration fluctuations and mass flux at the SWI. The sediment surface retains the signature of the overlying turbulent transport over long time scales, allowed by the slow bacterial absorption.

  14. Characterization of Lorenz number with Seebeck coefficient measurement

    SciTech Connect

    Kim, Hyun-Sik; Gibbs, Zachary M.; Tang, Yinglu; Wang, Heng; Snyder, G. Jeffrey

    2015-04-01

    In analyzing zT improvements due to lattice thermal conductivity (κ{sub L}) reduction, electrical conductivity (σ) and total thermal conductivity (κ{sub Total}) are often used to estimate the electronic component of the thermal conductivity (κ{sub E}) and in turn κ{sub L} from κ{sub L} = ∼ κ{sub Total} − LσT. The Wiedemann-Franz law, κ{sub E} = LσT, where L is Lorenz number, is widely used to estimate κ{sub E} from σ measurements. It is a common practice to treat L as a universal factor with 2.44 × 10{sup −8} WΩK{sup −2} (degenerate limit). However, significant deviations from the degenerate limit (approximately 40% or more for Kane bands) are known to occur for non-degenerate semiconductors where L converges to 1.5 × 10{sup −8} WΩK{sup −2} for acoustic phonon scattering. The decrease in L is correlated with an increase in thermopower (absolute value of Seebeck coefficient (S)). Thus, a first order correction to the degenerate limit of L can be based on the measured thermopower, |S|, independent of temperature or doping. We propose the equation: L=1.5+exp[−(|S|)/(116) ] (where L is in 10{sup −8} WΩK{sup −2} and S in μV/K) as a satisfactory approximation for L. This equation is accurate within 5% for single parabolic band/acoustic phonon scattering assumption and within 20% for PbSe, PbS, PbTe, Si{sub 0.8}Ge{sub 0.2} where more complexity is introduced, such as non-parabolic Kane bands, multiple bands, and/or alternate scattering mechanisms. The use of this equation for L rather than a constant value (when detailed band structure and scattering mechanism is not known) will significantly improve the estimation of lattice thermal conductivity.

  15. Heat transport in low-Rossby-number Rayleigh-Bénard convection.

    PubMed

    Julien, Keith; Knobloch, Edgar; Rubio, Antonio M; Vasil, Geoffrey M

    2012-12-21

    We demonstrate, via simulations of asymptotically reduced equations describing rotationally constrained Rayleigh-Bénard convection, that the efficiency of turbulent motion in the fluid bulk limits overall heat transport and determines the scaling of the nondimensional Nusselt number Nu with the Rayleigh number Ra, the Ekman number E, and the Prandtl number σ. For E < 1 inviscid scaling theory predicts and simulations confirm the large Ra scaling law Nu-1 ≈ C(1)σ(-1/2)Ra(3/2)E(2), where C(1) is a constant, estimated as C(1) ≈ 0.04 ± 0.0025. In contrast, the corresponding result for nonrotating convection, Nu-1 ≈ C(2)Ra(α), is determined by the efficiency of the thermal boundary layers (laminar: 0.28 ≤ α ≤ 0.31, turbulent: α ~ 0.38). The 3/2 scaling law breaks down at Rayleigh numbers at which the thermal boundary layer loses rotational constraint, i.e., when the local Rossby number ≈ 1. The breakdown takes place while the bulk Rossby number is still small and results in a gradual transition to the nonrotating scaling law. For low Ekman numbers the location of this transition is independent of the mechanical boundary conditions. PMID:23368470

  16. Investigation of Transonic Reynolds Number Scaling on a Twin-Engine Transport

    NASA Technical Reports Server (NTRS)

    Curtin, M. M.; Bogue, D. R.; Om, D.; Rivers, S. M. B.; Pendergraft, O. C., Jr.; Wahls, R. A.

    2002-01-01

    This paper discusses Reynolds number scaling for aerodynamic parameters including force and wing pressure measurements. A full-span model of the Boeing 777 configuration was tested at transonic conditions in the National Transonic Facility (NTF) at Reynolds numbers (based on mean aerodynamic chord) from 3.0 to 40.0 million. Data was obtained for a tail-off configuration both with and without wing vortex generators and flap support fairings. The effects of aeroelastics were separated from Reynolds number effects by varying total pressure and temperature independently. Data from the NTF at flight Reynolds number are compared with flight data to establish the wind tunnel/flight correlation. The importance of high Reynolds number testing and the need for developing a process for transonic Reynolds number scaling is discussed. This paper also identifies issues that need to be worked for Boeing Commercial to continue to conduct future high Reynolds number testing in the NTF.

  17. Phase Measurement of Galvanneal Task JPL Task Order Number: RF-152 Amendment Number: 543

    SciTech Connect

    Lynn Lowry; Beverly Tai

    1995-03-01

    The objective of this task was to demonstrate an x-ray fluorescence (XRF) technique which would measure the phase composition of galvanneal coatings of sheet steel rapidly and non-destructively with an accuracy of 0.5%. This data acquisition and analysis method would be implemented as an on-line process control input. The AISI sample matrix evaluated for this study is shown in Appendix I. The Jet Propulsion Laboratory (JPL) and Data Measurement Corporation (DMC) measured iron and zinc XRF responses from these samples. In addition, JPL performed metallograph, x-ray diffraction (XRD), and transmission electron microscopy (TEM) to characterize the samples' galvanneal phase morphology. This data was correlated with the XRF experimental results and then compared to phase composition models, which were generated using a Fundamental Parameters Method (FPM) approach.

  18. The variable number of tandem repeats element in DAT1 regulates in vitro dopamine transporter density

    PubMed Central

    VanNess, Sidney H; Owens, Michael J; Kilts, Clinton D

    2005-01-01

    Background A 40-bp variable number of tandem repeats (VNTR) polymorphism exists in the 15th exon of DAT1, the gene encoding the human dopamine transporter (DAT). Though the VNTR resides in a region encoding the 3' untranslated region (UTR) and does not alter the protein's amino acid sequence, the prevalent 10-repeat variant has shown both linkage and association to Attention Deficit Hyperactivity Disorder (ADHD). In this study, we examined the effects of the DAT1 VNTR on measures of in vitro DAT expression and pharmacology. A series of four DAT1 constructs, each containing the DAT1 coding region, but varying with respect to the downstream presence or content of the 3'UTR, were engineered and stably transfected into an HEK-293 variant using Flp-In integration, an enzyme-mediated, site-specific recombination technology. Results [3H] Win 35,428 saturation binding assays and DAT immunoblots revealed statistically significant differences in DAT expression attributable to DAT1 genotype. Cells harboring the 10-repeat DAT1 variant were characterized by a Bmax approximately 50% greater than cells with the 9-repeat VNTR; those containing only the DAT1 coding region or the coding region flanked by a truncated 3' UTR resulted in greater DAT density than either of the naturalistic 9- and 10-repeat variants. Competition binding assays showed no statistically significant DAT1 genotype effects on the DAT affinity for methylphenidate, a finding consistent with the positional location of the VNTR. Conclusion This study identified the DAT1 VNTR as a functional polymorphism and provides an interpretive framework for its association with behavioral phenotypes. PMID:16309561

  19. Heat transport measurements in turbulent rotating Rayleigh-Bénard convection.

    PubMed

    Liu, Yuanming; Ecke, Robert E

    2009-09-01

    We present experimental heat transport measurements of turbulent Rayleigh-Bénard convection with rotation about a vertical axis. The fluid, water with a Prandtl number (sigma) of about 6, was confined in a cell with a square cross section of 7.3 x 7.3 cm2 and a height of 9.4 cm. Heat transport was measured for Rayleigh numbers 2 x 10(5)numbers 0transport, the Nusselt number, at fixed dimensional rotation rate OmegaD, at fixed Ra varying Ta, at fixed Ta varying Ra, and at fixed Rossby number Ro. The scaling of heat transport in the range of 10(7) to about 10(9) is roughly 0.29 with a Ro-dependent coefficient or equivalently is also well fit by a combination of power laws of the form a Ra1/5+b Ra1/3. The range of Ra is not sufficient to differentiate single power law or combined power-law scaling. The data are roughly consistent with an assumption that the enhancement of heat transport owing to rotation is proportional to the number of vortical structures penetrating the boundary layer. We also compare indirect measures of thermal and Ekman boundary layer thicknesses to assess their potential role in controlling heat transport in different regimes of Ra and Ta. PMID:19905219

  20. Reynolds Number Effects on the Stability and Control Characteristics of a Supersonic Transport

    NASA Technical Reports Server (NTRS)

    Owens, L. R.; Wahls, R. A.; Elzey, M. B.; Hamner, M. P.

    2002-01-01

    A High Speed Civil Transport (HSCT) configuration was tested in the National Transonic Facility at the NASA Langley Research Center as part of NASA's High Speed Research Program. A series of tests included longitudinal and lateral/directional studies at transonic and low speed, high-lift conditions across a range of Reynolds numbers from that available in conventional wind tunnels to near flight conditions. Results presented focus on Reynolds number sensitivities of the stability and control characteristics at Mach 0.30 and 0.95 for a complete HSCT aircraft configuration including empennage. The angle of attack where the pitching-moment departure occurred increased with higher Reynolds numbers for both the landing and transonic configurations. The stabilizer effectiveness increased with Reynolds number for both configurations. The directional stability also increased with Reynolds number for both configurations. The landing configuration without forebody chines exhibited a large yawing-moment departure at high angles of attack and zero sideslip that varied with increasing Reynolds numbers. This departure characteristic nearly disappeared when forebody chines were added. The landing configuration's rudder effectiveness also exhibited sensitivities to changes in Reynolds number.

  1. Temperature and number density measurements using Raman scattering in turbulent-supersonic-combusting flows

    NASA Astrophysics Data System (ADS)

    Jeyashekar, Nigil Satish

    Scramjet engines propelled at hypersonic velocities have the potential to replace existing rocket launchers. Commercializing the vehicle is an arduous task, owing to issues relating to low combustion efficiency. The performance, thrust, and speed of the engine can be improved by optimizing: turbulence-chemistry interaction to provide mixing conditions favorable for the chemistry, pressure buildup, and re-circulation of hydrogen throughout the engine. The performance of the engine can be measured, flow and chemical dynamics can be evaluated when all three variables in the transport equations are known. The variables are instantaneous flow velocity, static temperature (refers to the macroscopic temperature and not the molecular species temperature), and total number density at a point in the flow. The motive is to build a non-intrusive tool to measure thermodynamic quantities (static temperature and total number density). This can be integrated with a velocity measurement tool, in the future, to obtain all three variables simultaneously and instantaneously. The dissertation describes in detail the motivation for the proposed work, with introduction to the formalism involved, with a concise literature review, followed by mathematical perspective to obtain the working equations for temperature and number density. The design of the adiabatic burner and the experimental setup used for calibration is discussed with the uncertainty involved in measurements. The measurements are made for a certain set of flow conditions in the laminar burner by Raman scattering and is validated by comparing it to the theoretical/adiabatic flame temperature and mole fraction plots, in lean and rich regime. This technique is applied to turbulent, supersonic, hydrogen-air flame of an afterburning rocket nozzle. The statistics of temperature and total number density versus the corresponding values at adiabatic conditions gives the departure from thermal and chemical equilibrium. The extent of mixing and combustion can be concluded from such statistics. The future work will involve experimental modifications to make line and planar measurements in combusting jets.

  2. Drag and Strouhal number measurements for porous circular cylinders

    NASA Astrophysics Data System (ADS)

    Kanale, Anup; Sellappan, Prabu; Luhar, Mitul

    2015-11-01

    Flow past solid bluff bodies has been studied extensively, and both experimental and computational results are well documented. However, there is limited data available for flows past porous bluff bodies, in spite of their abundance in nature. As an effort in this direction, we study the wake behind porous circular cylinders via water channel experiments employing particle image velocimetry (PIV). The experiments systematically test the effect of three dimensionless parameters: ReP , the Reynolds number based on pore size, ReD , the Reynolds number based on cylinder diamter, and ϕ the porosity of the sleeve. Specifically the PIV data are used to estimate the drag coefficient and Strouhal number for 600 <= ReD <= 5000 , 18 <= ReP <= 600 and 0 . 33 <= ϕ <= 0 . 75 . The results obtained are compared with solid cylinders to identify the effect of cylinder permeability on flow characteristics.

  3. Black Carbon Particle Number Distribution Measurements during the ATHENS-2013 Winter Campaign

    NASA Astrophysics Data System (ADS)

    Gkatzelis, Georgios; Papanastasiou, Dimitris; Florou, Kalliopi; Kaltsonoudis, Christos; Louvaris, Eyaggelos; Bezentakos, Spiridon; Biskos, Georgios; Pandis, Spuros

    2014-05-01

    Black Carbon (BC) particles emitted by anthropogenic sources play an important role both in climate change and in air quality degradation. Open burning in forests and savannas, combustion of diesel and solid fuels for cooking and heating in homes represent the majority of BC emissions. Earlier work has focused on the BC atmospheric direct radiative forcing that is mostly related to its mass concentration and optical properties of the corresponding particles. A variety of measurement techniques are used to measure the mass concentration of BC by taking advantage of its optical or physical properties. Moreover, the carbonaceous particles containing BC are also important for the indirect forcing of climate. This effect is mostly related to the number concentration of BC particles. The number distribution of BC particles especially below 100 nm is quite uncertain due to limitations of the existing measurement techniques. In this work we employed a thermodenuder-based method as an approach for the measurement of the BC number distribution. More specifically, we combined a thermodenuder (TD) operating at temperatures up to 300 ° C, with a Scanning Mobility Particle Sizer (SMPS) and a High Resolution Time of Flight Aerosol Mass Spectrometer (HR-ToF AMS). Aerosol size and composition measurements were carried out both at ambient and at elevated TD temperatures in Athens field campaign during January and February of 2013. In parallel, a Multi-Angle Absorption Photometer (MAAP) provided information about the BC mass concentration while a Hygroscopic Tandem Differential Mobility Analyzer (HTDMA) measured the mixing state and the hygroscopicity of the particles as a function of their size. These measurements were then combined to estimate the number concentration of BC particles. Our analysis focused on different periods during the study. During some of them one source dominated the carbonaceous aerosol concentration. Such periods included rush hour traffic, nighttime wood burning, clean air transported from other areas, mixed sources, etc. The number fraction remaining after heating at 300 ° C for approximately 15 s during wood burning events was 80-90%, suggesting that practically all particles contained nonvolatile material. Combining the SMPS, MAAP, AMS, and HTDMA measurements we show that most of the sampled material was BC. On the contrary, during rush hour traffic the number fraction remaining was only 50-60% suggesting that more than half of the particles did not contain BC.

  4. Numerical Computation of Mass Transport in Low Reynolds Number Flows and the Concentration Boundary Layer

    NASA Astrophysics Data System (ADS)

    Licata, Nicholas A.; Fuller, Nathaniel J.

    Understanding the physical mechanisms by which an individual cell interacts with its environment often requires detailed information about the fluid in which the cell is immersed. Mass transport between the interior of the cell and the external environment is influenced by the flow of the extracellular fluid and the molecular diffusivity. Analytical calculations of the flow field are challenging in simple geometries, and not generally available in more realistic cases with irregular domain boundaries. Motivated by these problems, we discuss the numerical solution of Stokes equation by implementing a Gauss-Seidel algorithm on a staggered computational grid. The computed velocity profile is used as input to numerically solve the advection-diffusion equation for mass transport. Special attention is paid to the case of two-dimensional flows at large Péclet number. The numerical results are compared with a perturbative analytical treatment of the concentration boundary layer.

  5. Temperature measurement and phonon number statistics of a nanoelectromechanical resonator

    NASA Astrophysics Data System (ADS)

    Neto, O. P. de S; deOliveira, M. C.; Milburn, G. J.

    2015-09-01

    Measuring thermodynamic quantities can be easy or not, depending on the system that is being studied. For a macroscopic object, measuring temperatures can be as simple as measuring how much a column of mercury rises when in contact with the object. At the small scale of quantum electromechanical systems, such simple methods are not available and invariably detection processes disturb the system state. Here we propose a method for measuring the temperature on a suspended semiconductor membrane clamped at both ends. In this method, the membrane is mediating a capacitive coupling between two transmission line resonators (TLR). The first TLR has a strong dispersion, that is, its decaying rate is larger than its drive, and its role is to pump in a pulsed way the interaction between the membrane and the second TLR. By averaging the pulsed measurements of the quadrature of the second TLR we show how the temperature of the membrane can be determined. Moreover the statistical description of the state of the membrane, which is directly accessed in this approach is significantly improved by the addition of a Josephson junction coupled to the second TLR.

  6. The Case for Multiple Measures. Info Brief. Number 52

    ERIC Educational Resources Information Center

    Fuller, Dan; Fitzgerald, Kevin; Lee, Ji Sun

    2008-01-01

    What is the best use for tests? Testing should provide insight and information to educators and students. The primary purpose of testing is to inform teaching and learning. Yet, for too many schools, testing has been perverted to accommodate only measurement. Lesson plans are built around helping students pass the tests. In many instances, schools…

  7. The number comb for a soil physical properties dynamic measurement

    NASA Astrophysics Data System (ADS)

    Olechko, K.; Patiño, P.; Tarquis, A. M.

    2012-04-01

    We propose the prime numbers distribution extracted from the soil digital multiscale images and some physical properties time series as the precise indicator of the spatial and temporal dynamics under soil management changes. With this new indicator the soil dynamics can be studied as a critical phenomenon where each phase transition is estimated and modeled by the graph partitioning induced phase transition. The critical point of prime numbers distribution was correlated with the beginning of Andosols, Vertisols and saline soils physical degradation under the unsustainable soil management in Michoacan, Guanajuato and Veracruz States of Mexico. The data banks corresponding to the long time periods (between 10 and 28 years) were statistically compared by RISK 5.0 software and our own algorithms. Our approach makes us able to distill free-form natural laws of soils physical properties dynamics directly from the experimental data. The Richter (1987) and Schmidt and Lipson (2009) original approaches were very useful to design the algorithms to identify Hamiltonians, Lagrangians and other laws of geometric and momentum conservation especially for erosion case.

  8. Measurement of tracheal mucous transport rate in the horse

    SciTech Connect

    Nelson, R.; Hampe, D.W.

    1983-06-01

    Tracheal mucous transport rates were measured in 12 nonanesthetized horses after an intratracheal injection of 99mtechnetium-sulfur colloid. The transport rate of the subsequent bolus of radioactivity was determined, using a portable scaler rate meter fitted with a high-energy gamma-scintillation probe. A gamma-scintillation camera was used to verify bolus form and movement in 1 horse. The mean tracheal mucous transport rate was 1.66 +/- 0.24 cm/min.

  9. Transport coefficients for the shear dynamo problem at small Reynolds numbers.

    PubMed

    Singh, Nishant K; Sridhar, S

    2011-05-01

    We build on the formulation developed in S. Sridhar and N. K. Singh [J. Fluid Mech. 664, 265 (2010)] and present a theory of the shear dynamo problem for small magnetic and fluid Reynolds numbers, but for arbitrary values of the shear parameter. Specializing to the case of a mean magnetic field that is slowly varying in time, explicit expressions for the transport coefficients α(il) and η(il) are derived. We prove that when the velocity field is nonhelical, the transport coefficient α(il) vanishes. We then consider forced, stochastic dynamics for the incompressible velocity field at low Reynolds number. An exact, explicit solution for the velocity field is derived, and the velocity spectrum tensor is calculated in terms of the Galilean-invariant forcing statistics. We consider forcing statistics that are nonhelical, isotropic, and delta correlated in time, and specialize to the case when the mean field is a function only of the spatial coordinate X(3) and time τ; this reduction is necessary for comparison with the numerical experiments of A. Brandenburg, K. H. Rädler, M. Rheinhardt, and P. J. Käpylä [Astrophys. J. 676, 740 (2008)]. Explicit expressions are derived for all four components of the magnetic diffusivity tensor η(il)(τ). These are used to prove that the shear-current effect cannot be responsible for dynamo action at small Re and Rm, but for all values of the shear parameter. PMID:21728649

  10. Transport coefficients for the shear dynamo problem at small Reynolds numbers

    SciTech Connect

    Singh, Nishant K.; Sridhar, S.

    2011-05-15

    We build on the formulation developed in S. Sridhar and N. K. Singh [J. Fluid Mech. 664, 265 (2010)] and present a theory of the shear dynamo problem for small magnetic and fluid Reynolds numbers, but for arbitrary values of the shear parameter. Specializing to the case of a mean magnetic field that is slowly varying in time, explicit expressions for the transport coefficients {alpha}{sub il} and {eta}{sub iml} are derived. We prove that when the velocity field is nonhelical, the transport coefficient {alpha}{sub il} vanishes. We then consider forced, stochastic dynamics for the incompressible velocity field at low Reynolds number. An exact, explicit solution for the velocity field is derived, and the velocity spectrum tensor is calculated in terms of the Galilean-invariant forcing statistics. We consider forcing statistics that are nonhelical, isotropic, and delta correlated in time, and specialize to the case when the mean field is a function only of the spatial coordinate X{sub 3} and time {tau}; this reduction is necessary for comparison with the numerical experiments of A. Brandenburg, K. H. Raedler, M. Rheinhardt, and P. J. Kaepylae [Astrophys. J. 676, 740 (2008)]. Explicit expressions are derived for all four components of the magnetic diffusivity tensor {eta}{sub ij}({tau}). These are used to prove that the shear-current effect cannot be responsible for dynamo action at small Re and Rm, but for all values of the shear parameter.

  11. MEASURED AND PREDICTED SOLUTE TRANSPORT IN A TILE DRAINED FIELD

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Most solute transport measurement techniques are tedious and require extensive soil excavation. A field experiment was conducted to evaluate whether surface transport properties determined by a non-destructive time domain reflectometry (TDR) technique could be used to accurately predict tile flux co...

  12. Optimal combination of number of participants and number of repeated measurements in longitudinal studies with time-varying exposure

    PubMed Central

    Barrera-Gómez, Jose; Spiegelman, Donna; Basagaña, Xavier

    2013-01-01

    In the context of observational longitudinal studies, we explored the values of the number of participants and the number of repeated measurements that maximize the power to detect the hypothesized effect, given the total cost of the study. We considered two different models, one that assumes a transient effect of exposure and one that assumes a cumulative effect. Results were derived for a continuous response variable, whose covariance structure was assumed to be damped exponential, and a binary time-varying exposure. Under certain assumptions, we derived simple formulas for the approximate solution to the problem in the particular case in which the response covariance structure is assumed to be compound symmetry. Results showed the importance of the exposure intraclass correlation in determining the optimal combination of the number of participants and the number of repeated measurements, and therefore the optimized power. Thus, incorrectly assuming a time-invariant exposure leads to inefficient designs. We also analyzed the sensitivity of results to dropout, mis-specification of the response correlation structure, allowing a time-varying exposure prevalence and potential confounding impact. We illustrated some of these results in a real study. In addition, we provide software to perform all the calculations required to explore the combination of the number of participants and the number of repeated measurements. PMID:23740818

  13. Transported acid aerosols measured in southern Ontario

    NASA Astrophysics Data System (ADS)

    Keeler, Gerald J.; Spengler, John D.; Koutrakis, Petros; Allen, George A.; Raizenne, Mark; Stern, Bonnie

    During the period 29 June 1986-9 August 1986, a field health study assessing the acute health effects of air pollutants on children was conducted at a summer girls' camp on the northern shore of Lake Erie in SW Ontario. Continuous air pollution measurements of SO 2, O 3, NO x, particulate sulfates, light scattering, and meteorological measurements including temperature, dew point, and wind speed and direction were made. Twelve-hour integrated samples of size fractioned particles were also obtained using dichotomous samplers and Harvard impactors equipped with an ammonia denuder for subsequent hydrogen ion determination. Particulate samples were analyzed for trace elements by X-ray fluorescence and Neutron Activation, and for organic and elemental carbon by a thermal/optical technique. The measured aerosol was periodically very acidic with observed 12-h averaged H + concentrations in the range < 10-560 nmoles m -3. The aerosol H + appeared to represent the net strong acidity after H 2SO 4 reaction with NH 3(g). Average daytime concentrations were higher than night-time for aerosol H +, sulfate, fine mass and ozone. Prolonged episodes of atmospheric acidity, sulfate, and ozone were associated with air masses arriving at the measurement site from the west and from the southwest over Lake Erie. Sulfate concentrations measured at the lakeshore camp were more than twice those measured at inland sites during extreme pollution episodes. The concentration gradient observed with onshore flow was potentially due to enhanced deposition near the lakeshore caused by discontinuities in the meteorological fields in this region.

  14. On-road particle number measurements using a portable emission measurement system (PEMS)

    NASA Astrophysics Data System (ADS)

    Gallus, Jens; Kirchner, Ulf; Vogt, Rainer; Börensen, Christoph; Benter, Thorsten

    2016-01-01

    In this study the on-road particle number (PN) performance of a Euro-5 direct-injection (DI) gasoline passenger car was investigated. PN emissions were measured using the prototype of a portable emission measurement system (PEMS). PN PEMS correlations with chassis dynamometer tests show a good agreement with a chassis dynamometer set-up down to emissions in the range of 1·1010 #/km. Parallel on-line soot measurements by a photo acoustic soot sensor (PASS) were applied as independent measurement technique and indicate a good on-road performance for the PN-PEMS. PN-to-soot ratios were 1.3·1012 #/mg, which was comparable for both test cell and on-road measurements. During on-road trips different driving styles as well as different road types were investigated. Comparisons to the world harmonized light-duty test cycle (WLTC) 5.3 and to European field operational test (euroFOT) data indicate the PEMS trips to be representative for normal driving. Driving situations in varying traffic seem to be a major contributor to a high test-to-test variability of PN emissions. However, there is a trend to increasing PN emissions with more severe driving styles. A cold start effect is clearly visible for PN, especially at low ambient temperatures down to 8 °C.

  15. Measuring aeolian sand transport using acoustic sensors

    NASA Astrophysics Data System (ADS)

    Poortinga, Ate; van Rheenen, Hans; Ellis, Jean T.; Sherman, Douglas J.

    2015-03-01

    Acoustic sensors are frequently used to measure aeolian saltation. Different approaches are used to process the signals from these instruments. The goal of this paper is to describe and discuss a method to measure aeolian saltation with acoustic sensors. In a laboratory experiment, we measured the output from an advanced signal processing scheme on the circuit board of the saltiphone. We use a software implementation of this processing scheme to re-analyse data from four miniphones obtained during a field experiment. It is shown that a set of filters remove background noise outside the frequency spectrum of aeolian saltation (at 8 kHz), whereas signals within this frequency spectrum are amplified. The resulting analogue signal is a proxy of the energy. Using an AC pulse convertor, this signal can be converted into a digital and analogue count signal or an analogue energy signal, using a rectifier and integrator. Spatio-temporal correlation between field deployed miniphones increases by using longer integration times for signal processing. To quantify aeolian grain impact, it is suggested to use the analogue energy output, as this mode is able to detect changes in frequency and amplitude. The analogue and digital count signals are able to detect an increase in frequency, but are not able to detect an increase in signal amplitude. We propose a two-stage calibration scheme consisting of (1) a factory calibration, to set the frequency spectrum of the sensor and (2) a standardized drop-test conducted before and after the experiment to evaluate the response of the sensor.

  16. Velocity Resolved---Scalar Modeled Simulations of High Schmidt Number Turbulent Transport

    NASA Astrophysics Data System (ADS)

    Verma, Siddhartha

    The objective of this thesis is to develop a framework to conduct velocity resolved - scalar modeled (VR-SM) simulations, which will enable accurate simulations at higher Reynolds and Schmidt (Sc) numbers than are currently feasible. The framework established will serve as a first step to enable future simulation studies for practical applications. To achieve this goal, in-depth analyses of the physical, numerical, and modeling aspects related to Sc " 1 are presented, specifically when modeling in the viscous-convective subrange. Transport characteristics are scrutinized by examining scalar-velocity Fourier mode interactions in Direct Numerical Simulation (DNS) datasets and suggest that scalar modes in the viscous-convective subrange do not directly affect large-scale transport for high Sc . Further observations confirm that discretization errors inherent in numerical schemes can be sufficiently large to wipe out any meaningful contribution from subfilter models. This provides strong incentive to develop more effective numerical schemes to support high Sc simulations. To lower numerical dissipation while maintaining physically and mathematically appropriate scalar bounds during the convection step, a novel method of enforcing bounds is formulated, specifically for use with cubic Hermite polynomials. Boundedness of the scalar being transported is effected by applying derivative limiting techniques, and physically plausible single sub-cell extrema are allowed to exist to help minimize numerical dissipation. The proposed bounding algorithm results in significant performance gain in DNS of turbulent mixing layers and of homogeneous isotropic turbulence. Next, the combined physical/mathematical behavior of the subfilter scalar-flux vector is analyzed in homogeneous isotropic turbulence, by examining vector orientation in the strain-rate eigenframe. The results indicate no discernible dependence on the modeled scalar field, and lead to the identification of the tensor-diffusivity model as a good representation of the subfilter flux. Velocity resolved - scalar modeled simulations of homogeneous isotropic turbulence are conducted to confirm the behavior theorized in these a priori analyses, and suggest that the tensor-diffusivity model is ideal for use in the viscous-convective subrange. Simulations of a turbulent mixing layer are also discussed, with the partial objective of analyzing Schmidt number dependence of a variety of scalar statistics. Large-scale statistics are confirmed to be relatively independent of the Schmidt number for Sc " 1, which is explained by the dominance of subfilter dissipation over resolved molecular dissipation in the simulations. Overall, the VR-SM framework presented is quite effective in predicting large-scale transport characteristics of high Schmidt number scalars, however, it is determined that prediction of subfilter quantities would entail additional modeling intended specifically for this purpose. The VR-SM simulations presented in this thesis provide us with the opportunity to overlap with experimental studies, while at the same time creating an assortment of baseline datasets for future validation of LES models, thereby satisfying the objectives outlined for this work.

  17. Learning from jellyfish: Fluid transport in muscular pumps at intermediate Reynolds numbers

    NASA Astrophysics Data System (ADS)

    Nawroth, Janna; Dabiri, John

    2010-11-01

    Biologically inspired hydrodynamic propulsion and maneuvering strategies promise the advancement of medical implants and minimally invasive clinical tools. We have chosen juvenile jellyfish as a model system for investigating fluid dynamics and morphological properties underlying fluid transport by a muscular pump at intermediate Reynolds numbers. Recently we have described how natural variations in viscous forces are balanced by changes in jellyfish body shape (phenotypic plasticity), to the effect of facilitating efficient body-fluid interaction. Complementing these studies in our live model organisms, we are also engaged in engineering an artificial jellyfish, that is, a jellyfish-inspired construct of a flexible plastic sheet actuated by a monolayer of rat cardiomyocytes. The main challenges here are (1) to derive a body shape and deformation suitable for effective fluid transport under physiological conditions, (2) to understand the mechanical properties of the muscular film and derive a design capable of the desired deformation, (3) to master the proper alignment and timely contraction of the muscle component needed to achieve the desired deformation, and (4) to evaluate the performance of the design.

  18. Effects of Lewis number on vorticity and enstrophy transport in turbulent premixed flames

    NASA Astrophysics Data System (ADS)

    Chakraborty, Nilanjan; Konstantinou, Ilias; Lipatnikov, Andrei

    2016-01-01

    The effects of Lewis number Le on both vorticity and enstrophy transport within the flame brush have been analysed using direct numerical simulation data of freely propagating statistically planar turbulent premixed flames, representing the thin reaction zone regime of premixed turbulent combustion. In the simulations, Le was ranged from 0.34 to 1.2 by keeping the laminar flame speed, thermal thickness, Damköhler, Karlovitz, and Reynolds numbers unchanged. The enstrophy has been shown to decay significantly from the unburned to the burned gas side of the flame brush in the Le ≈ 1.0 flames. However, a considerable amount of enstrophy generation within the flame brush has been observed for the Le = 0.34 case and a similar qualitative behaviour has been observed in a much smaller extent for the Le = 0.6 case. The vorticity components have been shown to exhibit anisotropic behaviour within the flame brush, and the extent of anisotropy increases with decreasing Le. The baroclinic torque term has been shown to be principally responsible for this anisotropic behaviour. The vortex stretching and viscous dissipation terms have been found to be the leading order contributors to the enstrophy transport for all cases, but the baroclinic torque and the sink term due to dilatation play increasingly important role for flames with decreasing Le. Furthermore, the correlation between the fluctuations of enstrophy and dilatation rate has been shown to play an important role in determining the material derivative of enstrophy based on the mean flow in the case of a low Le.

  19. Transport coefficients for the shear dynamo problem at small Reynolds numbers

    NASA Astrophysics Data System (ADS)

    Singh, Nishant K.; Sridhar, S.

    2011-05-01

    We build on the formulation developed in S. Sridhar and N. K. Singh [J. Fluid Mech.JFLSA70022-112010.1017/S0022112010003745 664, 265 (2010)] and present a theory of the shear dynamo problem for small magnetic and fluid Reynolds numbers, but for arbitrary values of the shear parameter. Specializing to the case of a mean magnetic field that is slowly varying in time, explicit expressions for the transport coefficients αil and ηiml are derived. We prove that when the velocity field is nonhelical, the transport coefficient αil vanishes. We then consider forced, stochastic dynamics for the incompressible velocity field at low Reynolds number. An exact, explicit solution for the velocity field is derived, and the velocity spectrum tensor is calculated in terms of the Galilean-invariant forcing statistics. We consider forcing statistics that are nonhelical, isotropic, and delta correlated in time, and specialize to the case when the mean field is a function only of the spatial coordinate X3 and time τ; this reduction is necessary for comparison with the numerical experiments of A. Brandenburg, K. H. Rädler, M. Rheinhardt, and P. J. Käpylä [Astrophys. J.AJLEEY0004-637X10.1086/527373 676, 740 (2008)]. Explicit expressions are derived for all four components of the magnetic diffusivity tensor ηij(τ). These are used to prove that the shear-current effect cannot be responsible for dynamo action at small Re and Rm, but for all values of the shear parameter.

  20. Gasificaton Transport: A Multiphase CFD Approach & Measurements

    SciTech Connect

    Dimitri Gidaspow; Veeraya Jiradilok; Mayank Kashyap; Benjapon Chalermsinsuwan

    2009-02-14

    The objective of this project was to develop predictive theories for the dispersion and mass transfer coefficients and to measure them in the turbulent fluidization regime, using existing facilities. A second objective was to use our multiphase CFD tools to suggest optimized gasifier designs consistent with aims of Future Gen. We have shown that the kinetic theory based CFD codes correctly compute: (1) Dispersion coefficients; and (2) Mass transfer coefficients. Hence, the kinetic theory based CFD codes can be used for fluidized bed reactor design without any such inputs. We have also suggested a new energy efficient method of gasifying coal and producing electricity using a molten carbonate fuel cell. The principal product of this new scheme is carbon dioxide which can be converted into useful products such as marble, as is done very slowly in nature. We believe this scheme is a lot better than the canceled FutureGen, since the carbon dioxide is safely sequestered.

  1. Nanoscale thermal transport measurements: Bridging ultrafast and steady-state

    NASA Astrophysics Data System (ADS)

    Green, Brian; Siemens, Mark; Sarah Mason Collaboration; Barry Zink Collaboration

    2014-03-01

    Macroscale thermal transport is explained by classical thermal diffusion, but as nanostructure length scales are reduced towards the order of the phonon mean free path, transport of thermal energy takes on a fundamentally different character. Nanoscale effects emerge such as sensitivity to the presence of surfaces and the onset of ballistic transport. We investigate nanoscale thermal physics by comparing results from two different transport measurement techniques applied to systems of highly confined thermal transport: metallic thin films deposited on a suspended bridge structure. One technique uses the transient thermoreflectance (TTR) method to measure picosecond cooling dynamics following ultrafast laser heating in a micron-sized region of the metallic film deposited on the bridge; the second is a DC technique that measures transport driven by an Ohmically-generated thermal gradient across the bridge through the full volume of the film. We find that these very different methods give similar results of significantly reduced thermal conductivity relative to macroscale values. We compare TTR and DC results between differing film thicknesses, and evaluate conductance uniformity across film surfaces. In combination, the TTR and DC methods are powerful tools for investigating and understanding thermal transport at the nanoscale. ACS Petroleum Research Fund.

  2. Molecular transport in collagenous tissues measured by gel electrophoresis.

    PubMed

    Hunckler, Michael D; Tilley, Jennifer M R; Roeder, Ryan K

    2015-11-26

    Molecular transport in tissues is important for drug delivery, nutrient supply, waste removal, cell signaling, and detecting tissue degeneration. Therefore, the objective of this study was to investigate gel electrophoresis as a simple method to measure molecular transport in collagenous tissues. The electrophoretic mobility of charged molecules in tissue samples was measured from relative differences in the velocity of a cationic dye passing through an agarose gel in the absence and presence of a tissue section embedded within the gel. Differences in electrophoretic mobility were measured for the transport of a molecule through different tissues and tissue anisotropy, or the transport of different sized molecules through the same tissue. Tissue samples included tendon and fibrocartilage from the proximal (tensile) and distal (compressive) regions of the bovine flexor tendon, respectively, and bovine articular cartilage. The measured electrophoretic mobility was greatest in the compressive region of the tendon (fibrocartilage), followed by the tensile region of tendon, and lowest in articular cartilage, reflecting differences in the composition and organization of the tissues. The anisotropy of tendon was measured by greater electrophoretic mobility parallel compared with perpendicular to the predominate collagen fiber orientation. Electrophoretic mobility also decreased with increased molecular size, as expected. Therefore, the results of this study suggest that gel electrophoresis may be a useful method to measure differences in molecular transport within various tissues, including the effects of tissue type, tissue anisotropy, and molecular size. PMID:26482732

  3. Automated measurement of fast mitochondrial transport in neurons

    PubMed Central

    Miller, Kyle E.; Liu, Xin-An; Puthanveettil, Sathyanarayanan V.

    2015-01-01

    There is growing recognition that fast mitochondrial transport in neurons is disrupted in multiple neurological diseases and psychiatric disorders. However, a major constraint in identifying novel therapeutics based on mitochondrial transport is that the large-scale analysis of fast transport is time consuming. Here we describe methodologies for the automated analysis of fast mitochondrial transport from data acquired using a robotic microscope. We focused on addressing questions of measurement precision, speed, reliably, workflow ease, statistical processing, and presentation. We used optical flow and particle tracking algorithms, implemented in ImageJ, to measure mitochondrial movement in primary cultured cortical and hippocampal neurons. With it, we are able to generate complete descriptions of movement profiles in an automated fashion of hundreds of thousands of mitochondria with a processing time of approximately one hour. We describe the calibration of the parameters of the tracking algorithms and demonstrate that they are capable of measuring the fast transport of a single mitochondrion. We then show that the methods are capable of reliably measuring the inhibition of fast mitochondria transport induced by the disruption of microtubules with the drug nocodazole in both hippocampal and cortical neurons. This work lays the foundation for future large-scale screens designed to identify compounds that modulate mitochondrial motility. PMID:26578890

  4. Diagnosing ocean energy transports from earth radiation budget measurements

    NASA Technical Reports Server (NTRS)

    Sohn, Byung-Ju; Smith, Eric A.

    1992-01-01

    The maximum energy production (MEP) principle suggested by Paltridge (1975) is applied to separate the satellite-inferred required total transports into the atmospheric and the oceanic components within a two-dimensional (2D) framework. For this purpose, the required 2D energy transports (Sohn and Smith, 1991) are imposed on Paltridge's energy balance model which is then solved as a variational problem. The results provide separated atmospheric and oceanic transports on a 2D basis such that the total divergence is equal to the net radiation measured from a satellite.

  5. A four-probe thermal transport measurement method for nanostructures

    NASA Astrophysics Data System (ADS)

    Kim, Jaehyun; Ou, Eric; Sellan, Daniel P.; Shi, Li

    2015-04-01

    Several experimental techniques reported in recent years have enabled the measurement of thermal transport properties of nanostructures. However, eliminating the contact thermal resistance error from the measurement results has remained a critical challenge. Here, we report a different four-probe measurement method that can separately obtain both the intrinsic thermal conductance and the contact thermal resistance of individual nanostructures. The measurement device consists of four microfabricated, suspended metal lines that act as resistive heaters and thermometers, across which the nanostructure sample is assembled. The method takes advantage of the variation in the heat flow along the suspended nanostructure and across its contacts to the four suspended heater and thermometer lines, and uses sixteen sets of temperature and heat flow measurements to obtain nine of the thermal resistances in the measurement device and the nanostructure sample, including the intrinsic thermal resistance and the two contact thermal resistances to the middle suspended segment of the nanostructure. Two single crystalline Si nanowires with different cross sections are measured in this work to demonstrate the effectiveness of the method. This four-probe thermal transport measurement method can lead to future discoveries of unique size-dependent thermal transport phenomena in nanostructures and low-dimensional materials, in addition to providing reliable experimental data for calibrating theoretical models.

  6. A four-probe thermal transport measurement method for nanostructures

    SciTech Connect

    Kim, Jaehyun; Ou, Eric; Sellan, Daniel P.; Shi, Li

    2015-04-15

    Several experimental techniques reported in recent years have enabled the measurement of thermal transport properties of nanostructures. However, eliminating the contact thermal resistance error from the measurement results has remained a critical challenge. Here, we report a different four-probe measurement method that can separately obtain both the intrinsic thermal conductance and the contact thermal resistance of individual nanostructures. The measurement device consists of four microfabricated, suspended metal lines that act as resistive heaters and thermometers, across which the nanostructure sample is assembled. The method takes advantage of the variation in the heat flow along the suspended nanostructure and across its contacts to the four suspended heater and thermometer lines, and uses sixteen sets of temperature and heat flow measurements to obtain nine of the thermal resistances in the measurement device and the nanostructure sample, including the intrinsic thermal resistance and the two contact thermal resistances to the middle suspended segment of the nanostructure. Two single crystalline Si nanowires with different cross sections are measured in this work to demonstrate the effectiveness of the method. This four-probe thermal transport measurement method can lead to future discoveries of unique size-dependent thermal transport phenomena in nanostructures and low-dimensional materials, in addition to providing reliable experimental data for calibrating theoretical models.

  7. Measurement of particle transport coefficients on Alcator C-Mod

    SciTech Connect

    Luke, T.C.T.

    1994-10-01

    The goal of this thesis was to study the behavior of the plasma transport during the divertor detachment in order to explain the central electron density rise. The measurement of particle transport coefficients requires sophisticated diagnostic tools. A two color interferometer system was developed and installed on Alcator C-Mod to measure the electron density with high spatial ({approx} 2 cm) and high temporal ({le} 1.0 ms) resolution. The system consists of 10 CO{sub 2} (10.6 {mu}m) and 4 HeNe (.6328 {mu}m) chords that are used to measure the line integrated density to within 0.08 CO{sub 2} degrees or 2.3 {times} 10{sup 16}m{sup {minus}2} theoretically. Using the two color interferometer, a series of gas puffing experiments were conducted. The density was varied above and below the threshold density for detachment at a constant magnetic field and plasma current. Using a gas modulation technique, the particle diffusion, D, and the convective velocity, V, were determined. Profiles were inverted using a SVD inversion and the transport coefficients were extracted with a time regression analysis and a transport simulation analysis. Results from each analysis were in good agreement. Measured profiles of the coefficients increased with the radius and the values were consistent with measurements from other experiments. The values exceeded neoclassical predictions by a factor of 10. The profiles also exhibited an inverse dependence with plasma density. The scaling of both attached and detached plasmas agreed well with this inverse scaling. This result and the lack of change in the energy and impurity transport indicate that there was no change in the underlying transport processes after detachment.

  8. MAGNETOROTATIONAL TURBULENCE TRANSPORTS ANGULAR MOMENTUM IN STRATIFIED DISKS WITH LOW MAGNETIC PRANDTL NUMBER BUT MAGNETIC REYNOLDS NUMBER ABOVE A CRITICAL VALUE

    SciTech Connect

    Oishi, Jeffrey S.

    2011-10-10

    The magnetorotational instability (MRI) may dominate outward transport of angular momentum in accretion disks, allowing material to fall onto the central object. Previous work has established that the MRI can drive a mean-field dynamo, possibly leading to a self-sustaining accretion system. Recently, however, simulations of the scaling of the angular momentum transport parameter {alpha}{sub SS} with the magnetic Prandtl number Pm have cast doubt on the ability of the MRI to transport astrophysically relevant amounts of angular momentum in real disk systems. Here, we use simulations including explicit physical viscosity and resistivity to show that when vertical stratification is included, mean-field dynamo action operates, driving the system to a configuration in which the magnetic field is not fully helical. This relaxes the constraints on the generated field provided by magnetic helicity conservation, allowing the generation of a mean field on timescales independent of the resistivity. Our models demonstrate the existence of a critical magnetic Reynolds number Rm{sub crit}, below which transport becomes strongly Pm-dependent and chaotic, but above which the transport is steady and Pm-independent. Prior simulations showing Pm dependence had Rm < Rm{sub crit}. We conjecture that this steady regime is possible because the mean-field dynamo is not helicity-limited and thus does not depend on the details of the helicity ejection process. Scaling to realistic astrophysical parameters suggests that disks around both protostars and stellar mass black holes have Rm >> Rm{sub crit}. Thus, we suggest that the strong Pm dependence seen in recent simulations does not occur in real systems.

  9. Magnetorotational Turbulence Transports Angular Momentum in Stratified Disks with Low Magnetic Prandtl Number but Magnetic Reynolds Number above a Critical Value

    SciTech Connect

    Oishi, Jeffrey S.; Low, Mordecai-Mark Mac; /Amer. Museum Natural Hist.

    2012-02-14

    The magnetorotational instability (MRI) may dominate outward transport of angular momentum in accretion disks, allowing material to fall onto the central object. Previous work has established that the MRI can drive a mean-field dynamo, possibly leading to a self-sustaining accretion system. Recently, however, simulations of the scaling of the angular momentum transport parameter {alpha}{sub SS} with the magnetic Prandtl number Pm have cast doubt on the ability of the MRI to transport astrophysically relevant amounts of angular momentum in real disk systems. Here, we use simulations including explicit physical viscosity and resistivity to show that when vertical stratification is included, mean field dynamo action operates, driving the system to a configuration in which the magnetic field is not fully helical. This relaxes the constraints on the generated field provided by magnetic helicity conservation, allowing the generation of a mean field on timescales independent of the resistivity. Our models demonstrate the existence of a critical magnetic Reynolds number Rm{sub crit}, below which transport becomes strongly Pm-dependent and chaotic, but above which the transport is steady and Pm-independent. Prior simulations showing Pm-dependence had Rm < Rm{sub crit}. We conjecture that this steady regime is possible because the mean field dynamo is not helicity-limited and thus does not depend on the details of the helicity ejection process. Scaling to realistic astrophysical parameters suggests that disks around both protostars and stellar mass black holes have Rm >> Rm{sub crit}. Thus, we suggest that the strong Pm dependence seen in recent simulations does not occur in real systems.

  10. Functional requirements for the Automated Transportation Management System: TTP number: RL 439002

    SciTech Connect

    Portsmouth, J.H.

    1992-12-31

    This requirements analysis, documents Department of Energy (DOE) transportation management procedures for the purpose of providing a clear and mutual understanding between users and designers of the proposed Automated Transportation Management System (ATMS). It is imperative that one understand precisely how DOE currently performs traffic management tasks; only then can an integrated system be proposed that successfully satisfies the major requirements of transportation managers and other system users. Accordingly, this report describes the current workings of DOE transportation organizations and then proposes a new system which represents a synthesis of procedures (both current and desired) which forms the basis for further systems development activities.

  11. Porous medium convection at large Rayleigh number: Studies of coherent structure, transport, and reduced dynamics

    NASA Astrophysics Data System (ADS)

    Wen, Baole

    Buoyancy-driven convection in fluid-saturated porous media is a key environmental and technological process, with applications ranging from carbon dioxide storage in terrestrial aquifers to the design of compact heat exchangers. Porous medium convection is also a paradigm for forced-dissipative infinite-dimensional dynamical systems, exhibiting spatiotemporally chaotic dynamics if not "true" turbulence. The objective of this dissertation research is to quantitatively characterize the dynamics and heat transport in two-dimensional horizontal and inclined porous medium convection between isothermal plane parallel boundaries at asymptotically large values of the Rayleigh number Ra by investigating the emergent, quasi-coherent flow. This investigation employs a complement of direct numerical simulations (DNS), secondary stability and dynamical systems theory, and variational analysis. The DNS confirm the remarkable tendency for the interior flow to self-organize into closely-spaced columnar plumes at sufficiently large Ra (up to Ra ≃ 105), with more complex spatiotemporal features being confined to boundary layers near the heated and cooled walls. The relatively simple form of the interior flow motivates investigation of unstable steady and time-periodic convective states at large Ra as a function of the domain aspect ratio L. To gain insight into the development of spatiotemporally chaotic convection, the (secondary) stability of these fully nonlinear states to small-amplitude disturbances is investigated using a spatial Floquet analysis. The results indicate that there exist two distinct modes of instability at large Ra: a bulk instability mode and a wall instability mode. The former usually is excited by long-wavelength disturbances and is generally much weaker than the latter. DNS, strategically initialized to investigate the fully nonlinear evolution of the most dangerous secondary instability modes, suggest that the (long time) mean inter-plume spacing in statistically-steady porous medium convection results from an interplay between the competing effects of these two types of instability. Upper bound analysis is then employed to investigate the dependence of the heat transport enhancement factor, i.e. the Nusselt number Nu, on Ra and L. To solve the optimization problems arising from the "background field" upper-bound variational analysis, a novel two-step algorithm in which time is introduced into the formulation is developed. The new algorithm obviates the need for numerical continuation, thereby enabling the best available bounds to be computed up to Ra ≈ 2.65 x 104. A mathematical proof is given to demonstrate that the only steady state to which this numerical algorithm can converge is the required global optimal of the variational problem. Using this algorithm, the dependence of the bounds on L( Ra) is explored, and a "minimal flow unit" is identified. Finally, the upper bound variational methodology is also shown to yield quantitatively useful predictions of Nu and to furnish a functional basis that is naturally adapted to the boundary layer dynamics at large Ra..

  12. Peclet number as affected by molecular diffusion controls transient anomalous transport in alluvial aquifer-aquitard complexes

    USGS Publications Warehouse

    Zhang, Yong; Green, Christopher T.; Tick, Geoffrey R.

    2015-01-01

    This study evaluates the role of the Peclet number as affected by molecular diffusion in transient anomalous transport, which is one of the major knowledge gaps in anomalous transport, by combining Monte Carlo simulations and stochastic model analysis. Two alluvial settings containing either short- or long-connected hydrofacies are generated and used as media for flow and transport modeling. Numerical experiments show that 1) the Peclet number affects both the duration of the power-law segment of tracer breakthrough curves (BTCs) and the transition rate from anomalous to Fickian transport by determining the solute residence time for a given low-permeability layer, 2) mechanical dispersion has a limited contribution to the anomalous characteristics of late-time transport as compared to molecular diffusion due to an almost negligible velocity in floodplain deposits, and 3) the initial source dimensions only enhance the power-law tail of the BTCs at short travel distances. A tempered stable stochastic (TSS) model is then applied to analyze the modeled transport. Applications show that the time-nonlocal parameters in the TSS model relate to the Peclet number, Pe. In particular, the truncation parameter in the TSS model increases nonlinearly with a decrease in Pe due to the decrease of the mean residence time, and the capacity coefficient increases with an increase in molecular diffusion which is probably due to the increase in the number of immobile particles. The above numerical experiments and stochastic analysis therefore reveal that the Peclet number as affected by molecular diffusion controls transient anomalous transport in alluvial aquifer–aquitard complexes.

  13. The Effects of Digital Measuring Equipment on the Concept of Number.

    ERIC Educational Resources Information Center

    Pickard, Poppy; Alexander, Patricia

    Over the last 20 years, the use of calculators and digital measuring equipment has to some extent replaced mathematical mental/written activity and also the use of analogue measuring equipment. This paper explores some aspects of number concept, reading the number line, and estimation from scales. The students being considered are mainly part of a…

  14. 41 CFR 102-117.270 - What are agency performance measures for transportation?

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... performance measures for transportation? 102-117.270 Section 102-117.270 Public Contracts and Property... TRANSPORTATION 117-TRANSPORTATION MANAGEMENT Performance Measures § 102-117.270 What are agency performance measures for transportation? (a) Agency performance measures are indicators of how you are supporting...

  15. 41 CFR 102-117.270 - What are agency performance measures for transportation?

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... performance measures for transportation? 102-117.270 Section 102-117.270 Public Contracts and Property... TRANSPORTATION 117-TRANSPORTATION MANAGEMENT Performance Measures § 102-117.270 What are agency performance measures for transportation? (a) Agency performance measures are indicators of how you are supporting...

  16. 41 CFR 102-117.270 - What are agency performance measures for transportation?

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... performance measures for transportation? 102-117.270 Section 102-117.270 Public Contracts and Property... TRANSPORTATION 117-TRANSPORTATION MANAGEMENT Performance Measures § 102-117.270 What are agency performance measures for transportation? (a) Agency performance measures are indicators of how you are supporting...

  17. 41 CFR 102-117.270 - What are agency performance measures for transportation?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... performance measures for transportation? 102-117.270 Section 102-117.270 Public Contracts and Property... TRANSPORTATION 117-TRANSPORTATION MANAGEMENT Performance Measures § 102-117.270 What are agency performance measures for transportation? (a) Agency performance measures are indicators of how you are supporting...

  18. Prediction uncertainty of plume characteristics derived from a small number of measuring points

    NASA Astrophysics Data System (ADS)

    French, H. K.; van der Zee, S. E. A. T. M.; Leijnse, A.

    A small number of measuring points may inflict a bias on the characterisation of flow and transport based on field experiments in the unsaturated zone. Simulation of pure advective transport of a Gaussian plume through a setup of 30 regularly placed measuring points revealed regular temporal fluctuations about the real spatial moments. An irregular setup predicted both irregular fluctuations and larger discrepancies from the real value. From these considerations, a regular setup is recommended. Spatial moments were sensitive to the plume size relative to the distance between individual measuring points. To reduce prediction errors of the variance, the distance between the measuring points should be less than twice the standard deviation of the examined plume. The total size of the setup should cover several standard deviations of the plume to avoid mass being lost from the monitored area. Numerical simulations of a dispersing plume (comparing calculations based on 9000 nodes with 30 measuring points) revealed that vertical and horizontal centres of mass were predicted well at all degrees of heterogeneity, and the same was the case for horizontal variances. Vertical variances were more susceptible to prediction errors, but estimates were of the same order of magnitude as the real values. Résumé Lorsque l'on cherche à caractériser l'écoulement et le transport à partir d'expériences de terrain dans la zone saturée, il arrive qu'un petit nombre de points introduisent un biais. La simulation d'un transport purement advectif d'un panache gaussien au travers d'un ensemble de 30 points de mesures espacés régulièrement fait apparaître des variations temporelles régulières autour des moments spatiaux réels. Un ensemble irrégulier conduit à prédire à la fois des variations irrégulières et de plus grandes divergences par rapport à la valeur réelle. A partir de ces constations, un ensemble régulier est recommandé. Les moments spatiaux sont apparus sensibles à la dimension du panache en fonction de la distance entre les différents points de mesure. Afin de réduire les erreurs de prédiction de la variance, la distance entre les points de mesure doit être inférieure au double de l'écart-type du panache examiné. La dimension totale de l'ensemble doit couvrir une étendue de plusieurs écarts-types du panache pour éviter qu'une partie de la matière échappe à la zone surveillée. Des simulations numériques du panache en dispersion (les calculs de comparaison sont basés sur 9000 nœuds avec 30 points de mesure) montrent que le centre vertical et le centre horizontal de la matière dispersée ont été bien prédits à tous les degrés d'hétérogénéité, de même que pour les variances horizontales. Les variances verticales ont été plus sensibles aux erreurs de prédiction, mais les estimations étaient du même ordre de grandeur que les valeurs réelles. Resumen Un número pequeño de puntos de medida puede producir un sesgo en la caracterización en campo del flujo y transporte de solutos en la zona no saturada. La simulación de transporte advectivo (no difusivo) de un penacho Gaussiano a travs de un conjunto de 30 puntos de medida regularmente distribuidos revelan fluctuaciones temporales regulares de los momentos espaciales del penacho. Una distribución irregular de puntos de medida predijo a su vez fluctuaciones irregulares, más alejadas de la realidad, por lo que se recomienda el uso de esquemas de muestreo regulares. Los momentos espaciales fueron sensibles a la relación entre tamaño del penacho y distancia entre puntos de medida. Para reducir los errores en la predicción de la varianza, la distancia entre puntos de observación debe ser menor que dos veces la desviación estándar del penacho. El tamaño del área muestreada debe cubrir varias desviaciones estándar del penacho para evitar perder parte de la masa. Las simulaciones numricas en un penacho dispersivo, comparando los cálculos basados en 9000 nudos con las 30 medidas, mostraron que las posiciones de los centros de masa y las varianzas en dirección horizontal se predijeron bien independientemente del grado de heterogeneidad. Las varianzas verticales, sin embargo, fueron más susceptibles a errores de predicción, pero las estimaciones eran del mismo orden de magnitud que los valores reales.

  19. Capacitance-Voltage Measurement of Transporting Function at Cell Membrane

    NASA Astrophysics Data System (ADS)

    Sakata, Toshiya; Miyahara, Yuji

    In this paper, we report the detection of transporting function at cell membrane using capacitance-voltage (CV) measurement. The detection principle of our devices is based on the field-effect of electrostatic interaction between charged species at cell membrane in solution and surface electrons in silicon crystal through the gate insulator of Si3N4/SiO2 thin double-layer. We designed an oocyte-based field-effect capacitor, on which a Xenopus laevis oocyte was fixed. The transporter of human organic anion transporting peptide C (hOATP-C) was expressed at oocyte membrane by induction of cRNA. The electrical phenomena such as ion or molecular charge flux at the interface between cell membrane and gate surface could be detected as the change of flat band voltage in CV characteristics. The flat band voltage shift decreased with incubation time after introduction of substrate into the oocyte-based field-effect capacitor. The electrical signal is due to the change of charge flux from the oocyte at the gate surface inspired by transporter-substrate binding. The platform based on the oocyte-based field-effect capacitor is suitable for a simple and non-invasive detection system in order to analyze function of transporters related to drug efficacy.

  20. A rain splash transport equation assimilating field and laboratory measurements

    USGS Publications Warehouse

    Dunne, T.; Malmon, D.V.; Mudd, S.M.

    2010-01-01

    Process-based models of hillslope evolution require transport equations relating sediment flux to its major controls. An equation for rain splash transport in the absence of overland flow was constructed by modifying an approach developed by Reeve (1982) and parameterizing it with measurements from single-drop laboratory experiments and simulated rainfall on a grassland in East Africa. The equation relates rain splash to hillslope gradient, the median raindrop diameter of a storm, and ground cover density; the effect of soil texture on detachability can be incorporated from other published results. The spatial and temporal applicability of such an equation for rain splash transport in the absence of overland flow on uncultivated hillslopes can be estimated from hydrological calculations. The predicted transport is lower than landscape-averaged geologic erosion rates from Kenya but is large enough to modify short, slowly eroding natural hillslopes as well as microtopographic interrill surfaces between which overland flow transports the mobilized sediment. Copyright 2010 by the American Geophysical Union. Copyright 2010 by the American Geophysical Union.

  1. Direct measurement of electrical transport through single DNA molecules

    NASA Astrophysics Data System (ADS)

    Qian, Jun; Liao, Sicheng; Xu, Song; Stroscio, Michael A.; Dutta, Mitra

    2009-08-01

    The apparently contradictory results indicating the ability of DNA to transport charge as well as the possible charge transport mechanisms in DNA have been addressed by making scanning tunneling microscopy (STM) or current-sensing atomic force microscopy measurements using gold nanoparticle (GNP)-DNA complexes bound to a gold substrate designed to minimize nonreproducibility of the specific binding modes and configurations of the DNA-metal contacts. Using these GNP-DNA complexes but a different strand of DNA [13-base-pair poly(dA)-poly(dT) double-stranded DNA] and STM, semiconductorlike charge transport characteristics are demonstrated for DNA; importantly, several different observed I-V characteristics are correlated with different configurations of GNP-DNA complexes as well as with I-V characteristics calculated using a Landauer formalism. These joint measured and simulated I-V characteristics for the GNP-DNA complexes are consistent with charge transport in a semiconductor where the lowest unoccupied molecular orbital energy of the DNA serves as the lowest conduction band energy and the highest occupied molecular orbital energy of the DNA serves as the highest valence band energy.

  2. Transportation energy strategy: Project {number_sign}5 of the Hawaii Energy Strategy Development Program

    SciTech Connect

    1995-08-01

    This study was prepared for the State Department of Business, Economic Development and Tourism (DBEDT) as part of the Hawaii Energy Strategy program. Authority and responsibility for energy planning activities, such as the Hawaii Energy Strategy, rests with the State Energy Resources Coordinator, who is the Director of DBEDT. Hawaii Energy Strategy Study No. 5, Transportation Energy Strategy Development, was prepared to: collect and synthesize information on the present and future use of energy in Hawaii`s transportation sector, examine the potential of energy conservation to affect future energy demand; analyze the possibility of satisfying a portion of the state`s future transportation energy demand through alternative fuels; and recommend a program targeting energy use in the state`s transportation sector to help achieve state goals. The analyses and conclusions of this report should be assessed in relation to the other Hawaii Energy Strategy Studies in developing a comprehensive state energy program. 56 figs., 87 tabs.

  3. Analysis of in vitro iontophoretic skin permeation of sodium benzoate by transport numbers of drug and additives.

    PubMed

    Numajiri, S; Sugibayashi, K; Morimoto, Y

    1996-07-01

    Effect of species and concentrations of pharmaceutical additives on the iontophoretic transport of benzoate anion through excised hairless rat skin was investigated using a 2-chamber iontophoretic diffusion cell equipped with platinum electrodes at 0 mA for 4h (control) followed by a constant direct current of 0.5 mA for another 4h. One cell facing the stratum corneum was filled with sodium benzoate solution, and the other cell facing the dermis with lithium chloride (LiCl), potassium chloride (KCl) or tetraethylammonium bromide (TEA-Br) solution. Iontophoretic delivery rate of benzoate anion that permeated through skin increased with an increase in the sodium benzoate concentration while maintaining a constant KCl concentration. In contrast, a flux of benzoate anion decreased with an increase in KCl concentration and a constant concentration of sodium benzoate. When KCl was replaced by LiCl or TEA-Br, the flux of benzoate anion was almost the same. These phenomena were evaluated by a concept of transport numbers: theoretical values of benzoate anion flux were very close to the observed data. Potential difference between the skin during the permeation study was also measured between two salt bridges which were connected via calomel electrodes to a potentiometer. It gradually decreased to a certain level in each case, but increased again in some cases. This gradual decrease and increase in the potential difference, in spite of a constant current, were theoretically explained by a gradual increase of ion concentration in the skin membrane and depletion of the cation in the receiver cell, respectively. Analysis of ionic mobility and concentration of penetrants gave a great deal of information on iontophoretic drug permeation through skin. PMID:8706142

  4. Review on measurement techniques of transport properties of nanowires.

    PubMed

    Rojo, Miguel Muñoz; Calero, Olga Caballero; Lopeandia, A F; Rodriguez-Viejo, J; Martín-Gonzalez, Marisol

    2013-12-01

    Physical properties at the nanoscale are novel and different from those in bulk materials. Over the last few decades, there has been an ever growing interest in the fabrication of nanowire structures for a wide variety of applications including energy generation purposes. Nevertheless, the study of their transport properties, such as thermal conductivity, electrical conductivity or Seebeck coefficient, remains an experimental challenge. For instance, in the particular case of nanostructured thermoelectrics, theoretical calculations have shown that nanowires offer a promising way of enhancing the hitherto low efficiency of these materials in the conversion of temperature differences into electricity. Therefore, within the thermoelectrical community there has been a great experimental effort in the measurement of these quantities in actual nanowires. The measurements of these properties at the nanoscale are also of interest in fields other than energy, such as electrical components for microchips, field effect transistors, sensors, and other low scale devices. For all these applications, knowing the transport properties is mandatory. This review deals with the latest techniques developed to perform the measurement of these transport properties in nanowires. A thorough overview of the most important and modern techniques used for the characterization of different kinds of nanowires will be shown. PMID:24113712

  5. Optimal number of repeated measures and group sizes in clinical trials with linearly divergent treatment effects.

    PubMed

    Winkens, Bjorn; Schouten, Hubert J A; van Breukelen, Gerard J P; Berger, Martijn P F

    2006-02-01

    The effect of number of repeated measures on the variance of the generalized least squares (GLS) treatment effect estimator is considered assuming a linearly divergent treatment effect, equidistant time-points and either a fixed number of subjects or a fixed study budget. The optimal combination of group sizes and number of repeated measures is calculated by minimizing this variance subject to a linear cost function. For a fixed number of subjects, the variance of the GLS treatment effect estimator can be decreased by adding intermediate measures per subject. This decrease is relatively large if a) the covariance structure is compound symmetric or b) the structure approaches compound symmetry and the correlation between two repeated measures does not exceed 0.80, or c) the correlation between two repeated measures does not exceed 0.60 if the time-lag goes to zero. In case the sample sizes and number of repeated measures are limited by budget constraints and the covariance structure includes a first-order auto-regression part, two repeated measures per subject yield highly efficient treatment effect estimators. Otherwise, it is more efficient to have more than two repeated measures. If the covariance structure is unknown, the optimal design based on a first-order auto-regressive structure with measurement error is preferable in terms of robustness against misspecification of the covariance structure. The numerical results are illustrated by three examples. PMID:16260188

  6. Rapid Measurement of Neutron Dose Rate for Transport Index

    SciTech Connect

    Morris, R.L.

    2000-02-27

    A newly available neutron dose equivalent remmeter with improved sensitivity and energy response has been put into service at Rocky Flats Environmental Technology Site (RFETS). This instrument is being used to expedite measurement of the Transport Index and as an ALARA tool to identify locations where slightly elevated neutron dose equivalent rates exist. The meter is capable of measuring dose rates as low as 0.2 {mu}Sv per hour (20 {mu}rem per hour). Tests of the angular response and energy response of the instrument are reported. Calculations of the theoretical instrument response made using MCNP{trademark} are reported for materials typical of those being shipped.

  7. Quantitative effective atomic number imaging using simultaneous x-ray absorption and phase shift measurement

    NASA Astrophysics Data System (ADS)

    Mukaide, Taihei; Watanabe, Masatoshi; Takada, Kazuhiro; Iida, Atsuo; Fukuda, Kazunori; Noma, Takashi

    2011-03-01

    A scanning type x-ray imaging system which measures the absorption and differential phase shift in a material quantitatively and simultaneously has been developed. The absorption and differential phase are used to obtain the effective atomic number of organic material samples which closely reflects their chemical composition. An effective atomic number map of polymer fibers has been obtained. The experimentally obtained effective atomic numbers of these polymers agree well with the corresponding calculated values.

  8. Measurement of the effective atomic numbers of compounds with cerium near to the absorption edge

    NASA Astrophysics Data System (ADS)

    Polat, Recep; İçelli, Orhan

    2010-04-01

    In order to measure atomic, molecular and electronic cross-section; the effective atomic number, density of electron and absorption jump factor, we have first measured μ t values of compounds which are determined by mixture rule using transmission method. In order to measure experimentally the effective atomic number within absorption jump factors of compounds with Ce, the X-ray source used Am-241 whose gamma rays were stopped at secondary source (Sm), thus producing Kα and Kβ X-ray emission. The most crucial finding in this study is that measurement of the effective atomic number is not appropriate near to the absorption edge and the effective atomic number is affected by near to the absorption edge. The results obtained have been compared with theoretical values.

  9. Mach-Number Measurement with Laser and Pressure Probes in Humid Supersonic Flow

    NASA Technical Reports Server (NTRS)

    Herring, G. C.

    2008-01-01

    Mach-number measurements using a nonintrusive optical technique, laser-induced thermal acoustics (LITA), are compared to pressure probes in humid supersonic airflow. The two techniques agree well in dry flow (-35 C dew point), but LITA measurements show about five times larger fractional change in Mach number than that of the pressure-probe when water is purposefully introduced into the flow. Possible reasons for this discrepancy are discussed.

  10. Measurements of the dependence of the photon-number distribution on the number of modes in parametric down-conversion.

    PubMed

    Dovrat, L; Bakstein, M; Istrati, D; Shaham, A; Eisenberg, H S

    2012-01-30

    Optical parametric down-conversion (PDC) is a central tool in quantum optics experiments. The number of collected down-converted modes greatly affects the quality of the produced photon state. We use Silicon Photomultiplier (SiPM) number-resolving detectors in order to observe the photon-number distribution of a PDC source, and show its dependence on the number of collected modes. Additionally, we show how the stimulated emission of photons and the partition of photons into several modes determine the overall photon number. We present a novel analytical model for the optical crosstalk effect in SiPM detectors, and use it to analyze the results. PMID:22330466

  11. Computer Applications in Class and Transportation Scheduling. Educational Management Review Series Number 1.

    ERIC Educational Resources Information Center

    Piele, Philip K.

    This document shows how computer technology can aid educators in meeting demands for improved class scheduling and more efficient use of transportation resources. The first section surveys literature on operational systems that provide individualized scheduling for students, varied class structures, and maximum use of space and staff skills.…

  12. The Indonesian's Road Transportations as the Contexts to Support Primary School Students Learning Number Operation

    ERIC Educational Resources Information Center

    Kairuddin; Darmawijoyo

    2011-01-01

    This paper highlights the Indonesian's road transportation contexts, namely, angkot, that used in learning and teaching of addition and subtraction in first grade and second grade MIN-2 Palembang. PMRI approach that adopt from RME [Realistic Mathematics Education] was used in this design research. From teaching experiment was founded that the…

  13. The influence of passage number for Caco2 cell models when evaluating P-gp mediated drug transport.

    PubMed

    Senarathna, S M D K Ganga; Crowe, A

    2015-12-01

    Caco2 cells are a human adenocarcinoma cell line that forms tight junctions and are widely used to examine bidirectional drug transport as well as P-glycoprotein mediated efflux. Unfortunately Caco2 cell lines can be very heterogeneous in nature. Our aim was to improve the Caco2 cell model for determination of P-glycoprotein mediated drug transport. Young passage Caco2 from ATCC had inadequate expression of P-glycoprotein, therefore three approaches were adopted to upregulate Caco2 P-glycoprotein expression to mimic that in vivo; a) incubation of mature Caco2 monolayer with rifampicin, b) prolonged exposure of Caco2 cells to vinblastine (generating the Caco2 VIN line), and c) splitting cells every 7 to 9 days until late passage numbers (over P80) were available. Upon development of the models, P-gp expression and activity was determined using western blotting and bidirectional transport studies of rhodamine123. All four models exhibited P-gp mediated efflux transport for rhodamine123. Incubation with rifampicin did not alter bidirectional transport compared to passage 44 cells. Increased passage number altered P-glycoprotein expression and the efflux ratio increased to 4.7 for passage 80 from 1.4 of passage 44. The highest basolateral to apical transport was observed for both passage 89 Caco2 and the Caco2 VIN model with an efflux ratio of 13 to 14. Western blot images confirmed the increased P-glycoprotein expression of late passage and Caco2 VIN. Caco2 cells are not ready for P-gp related research when first acquired from ATCC (Passage 18). Late passage Caco2 cell monolayers or Caco2 VIN models are needed to determine P-gp mediated efflux transport. PMID:26817277

  14. Moisture dependence of radon transport in concrete: measurements and modeling.

    PubMed

    Cozmuta, I; van der Graaf, E R; de Meijer, R J

    2003-10-01

    The moisture dependence of the radon-release rate of concrete was measured under well controlled conditions. It was found that the radon-release rate almost linearly increases up to moisture contents of 50 to 60%. At 70 to 80% a maximum was found and for higher moisture contents the radon-release rate decreases very steeply. It is demonstrated that this dependence can be successfully modeled on basis of the multi-phase radon-transport equation in which values for various input parameters (porosity, diffusion coefficient, emanation factor, etc.) were obtained from independent measurements. Furthermore, a concrete structure development model was used to predict at any moment in time the values of input parameters that depend on the evolution of the concrete microstructure. Information on the concrete manufacturing recipe and curing conditions (temperature, relative humidity) was used as input for the concrete structure model. The combined radon transport and concrete structure model supplied sufficient information to assess the influence of relative humidity on the radon source and barrier aspects of concrete. More specifically, the model has been applied to estimate the relative contributions to the radon exhalation rate of a 20-cm-thick concrete slab of radon produced in the concrete slab itself and due to diffusive transport through the slab of radon from soil gas. PMID:13678285

  15. Distance-Based Functional Diversity Measures and Their Decomposition: A Framework Based on Hill Numbers

    PubMed Central

    Chiu, Chun-Huo; Chao, Anne

    2014-01-01

    Hill numbers (or the “effective number of species”) are increasingly used to characterize species diversity of an assemblage. This work extends Hill numbers to incorporate species pairwise functional distances calculated from species traits. We derive a parametric class of functional Hill numbers, which quantify “the effective number of equally abundant and (functionally) equally distinct species” in an assemblage. We also propose a class of mean functional diversity (per species), which quantifies the effective sum of functional distances between a fixed species to all other species. The product of the functional Hill number and the mean functional diversity thus quantifies the (total) functional diversity, i.e., the effective total distance between species of the assemblage. The three measures (functional Hill numbers, mean functional diversity and total functional diversity) quantify different aspects of species trait space, and all are based on species abundance and species pairwise functional distances. When all species are equally distinct, our functional Hill numbers reduce to ordinary Hill numbers. When species abundances are not considered or species are equally abundant, our total functional diversity reduces to the sum of all pairwise distances between species of an assemblage. The functional Hill numbers and the mean functional diversity both satisfy a replication principle, implying the total functional diversity satisfies a quadratic replication principle. When there are multiple assemblages defined by the investigator, each of the three measures of the pooled assemblage (gamma) can be multiplicatively decomposed into alpha and beta components, and the two components are independent. The resulting beta component measures pure functional differentiation among assemblages and can be further transformed to obtain several classes of normalized functional similarity (or differentiation) measures, including N-assemblage functional generalizations of the classic Jaccard, Sørensen, Horn and Morisita-Horn similarity indices. The proposed measures are applied to artificial and real data for illustration. PMID:25000299

  16. Regulation of the number of spiders participating in collective prey transport in the social spider Anelosimus eximius (Araneae, Theridiidae).

    PubMed

    Vakanas, Guillaume; Krafft, Bertrand

    2004-08-01

    In an experimental study, mechanisms by which cooperative prey transport is achieved in social spiders were clarified. Factors that could influence the number of individuals that participate in prey transport (prey mass, length and vibration) were investigated. Results show that two factors are fundamental: the vibrations and the prey length. Prey mass did not seem to influence spiders' participation. Thus, the single fact that individuals respond locally to environmental stimuli (intensity of vibration, available site on the prey) explains how spiders cooperate and efficiently capture a wide range of prey types without complex communication systems. PMID:15506525

  17. The Manned Transportation System Study - Attributes and their measurements

    NASA Technical Reports Server (NTRS)

    Geyer, M. S.; Bienhoff, D. G.; Carey, D. A.; Clark, B. C.; Emmet, B. R.; Lance, N.; Kerwin, J.; Mccandless, B.; Wetzel, E. D.; Sooter, C. W.

    1992-01-01

    Attention is given to the Manned Transportation System (MTS) Study, initiated to help identify the 'right' transportation system architectures needed for human access to space. A listing of the requirements used for this study and the rationale behind them are given. Attributes allow comparison of elements that meet the requirements and the 'needs' (mission model). The attributes include: safety, probability of mission success, funding profile, architecture cost risk, schedule confidence, dependability, availability, mission growth potential, environment, resiliency, and alternate access. The attributes need to be measurable, to have repeatable calculations and well-defined assumptions, to have their weight determined relative to other attributes, and to be a discriminator. The process used to determine the attributes, which involved the MTS team forum and some of the quality function deployment techniques, is discussed.

  18. Generalized emittance measurements in a beam transport line

    SciTech Connect

    Skelly, J.; Gardner, C.; Luccio, A.; Kponou, A.; Reece, K.

    1991-01-01

    Motivated by the need to commission 3 beam transport lines for the new AGS Booster project, we have developed a generalized emittance-measurement program; beam line specifics are entirely resident in data tables, not in program code. For instrumentation, the program requires one or more multi-wire profile monitors; one or multiple profiles are acquired from each monitor, corresponding to one or multiple tunes of the transport line. Emittances and Twiss parameters are calculated using generalized algorithms. The required matix descriptions of the beam optics are constructed by an on-line general beam modeling program. Design of the program, its algorithms, and initial experience with it will be described. 4 refs., 2 figs., 1 tab.

  19. Modeling a Conventional Electroporation Pulse Train: Decreased Pore Number, Cumulative Calcium Transport and an Example of Electrosensitization.

    PubMed

    Son, Reuben S; Gowrishankar, Thiruvallur R; Smith, Kyle C; Weaver, James C

    2016-03-01

    Pulse trains are widely used in electroporation (EP) for both general biomedical research and clinical applications such as nonthermal tumor ablation. Here we use a computational method based on a meshed transport network to investigate a cell system model's response to a train of identical, evenly spaced electric field pulses. We obtain an unexpected result: the number of membrane pores decreases during the application of twenty 1.0 kV/cm, 100  μs pulses, delivered at 1 Hz. This pulse train initially creates 13,000 membrane pores, but pore number decreases by a factor of 15 to about 830 pores throughout subsequent pulses. We conclude that pore number can greatly diminish during a train of identical pulses, with direct consequences for the transport of solutes across an electroporated membrane. Although application of additional pulses is generally intended to increase the effects of EP, we show that these pulses do not significantly enhance calcium delivery into the cell. Instead, calcium delivery can be significantly increased by varying inter-pulse intervals. We show that inserting a 300-s interruption midway in a widely used eight-pulse train (a protocol for electrosensitization) yields a  ∼ twofold delivery increase. Overall, our modeling shows support for electrosensitization, in which multiple pulse protocols that maximize pore number over time can yield significant increase of transport of calcium compared to standard pulse trains. PMID:26302502

  20. Unsteady pressure measurements on a supercritical airfoil at high Reynolds numbers

    NASA Technical Reports Server (NTRS)

    Hess, R. W.

    1989-01-01

    Steady and unsteady pressures were measured on a 14 percent supercritical airfoil at transonic Mach numbers at Reynolds numbers from 6,000,000 to 35,000,000. Instrumentation techniques were developed to measure unsteady pressures in a cryogenic tunnel at flight Reynolds numbers. Experimental steady data, corrected for wall effects show very good agreement with calculations from a full potential code with an interacted boundary layer. The steady and unsteady pressures both show a shock position that is dependent on Reynolds number. For a supercritical pressure distribution at a chord Reynolds number of 35,000,000 laminar flow was observed between the leading edge and the shock wave at 45 percent chord.

  1. Boundary-layer measurements on a high Reynolds number three-element airfoil

    NASA Technical Reports Server (NTRS)

    Selby, Gregory V.

    1992-01-01

    An experimental investigation is being conducted to evaluate the boundary layer associated with a two-dimensional three-element single-flap airfoil at high Reynolds numbers. The present measurements are being made in the Langley Low-Turbulence (centerline turbulence intensity level is 0.034 percent at a Mach number of 0.2 and a total pressure of 60 psia) Pressure Tunnel (LTPT). The LTPT is a closed-circuit wind tunnel with a test section which is 3 ft wide, 7.5 ft high, and 7.5 ft long. Operating total pressure for the LTPT varies from 10 atmospheres to near-vacuum conditions. Tests are being conducted at a Mach number of 0.2 and Reynolds numbers (based on chord length) of 5, 9, and 16 million. Measurements include boundary-layer velocity surveys at several chordwise locations and surface skin-friction measurements using Preston tubes.

  2. On the speckle number of interferometric velocity and distance measurements of moving rough surfaces.

    PubMed

    Kuschmierz, Robert; Koukourakis, Nektarios; Fischer, Andreas; Czarske, Jrgen

    2014-10-01

    The minimum achievable systematic uncertainty of interferometric measurements is fundamentally limited due to speckle noise. Numerical and physical experiments, regarding the achievable measurement uncertainty of Mach-Zehnder based velocity and position sensors, are presented at the example of the laser Doppler distance sensor with phase evaluation. The results show that the measurement uncertainty depends on the number of speckles on the photo detectors. However, while the systematic uncertainty due to the speckle effect decreases, the random uncertainty due to noise from the photo detector increases with increasing speckle number. This results in a minimal total measurement uncertainty for an optimal speckle number on the photo detector, which is achieved by adjusting the aperture of the detection optics. PMID:25360943

  3. Nanoscale Electron Transport Measurements of Immobilized Cytochrome P450 Proteins

    PubMed Central

    Bostick, Christopher D.; Flora, Darcy R.; Gannett, Peter M.; Tracy, Timothy S.; Lederman, David

    2015-01-01

    Gold nanopillars, functionalized with an organic self-assembled monolayer, can be used to measure the electrical conductance properties of immobilized proteins without aggregation. Measurements of the conductance of nanopillars with cytochrome P450 2C9 (CYP2C9) proteins using conducting probe atomic force microscopy demonstrate that a correlation exists between the energy barrier height between hopping sites and CYP2C9 metabolic activity. Measurements performed as a function of tip force indicate that, when subjected to a large force, the protein is more stable in the presence of a substrate. This agrees with the hypothesis that substrate entry into the active site helps to stabilize the enzyme. The relative distance between hopping sites also increases with increasing force, possibly because protein functional groups responsible for electron transport depend on the structure of the protein. The inhibitor sulfaphenazole, in addition to the previously studied aniline, increased the barrier height for electron transfer and thereby makes CYP2C9 reduction more difficult and inhibits metabolism. This suggests that P450 Type II binders may decrease the ease of electron transport processes in the enzyme, in addition to occupying the active site. PMID:25804257

  4. Accurate measurement of liquid transport through nanoscale conduits

    PubMed Central

    Alibakhshi, Mohammad Amin; Xie, Quan; Li, Yinxiao; Duan, Chuanhua

    2016-01-01

    Nanoscale liquid transport governs the behaviour of a wide range of nanofluidic systems, yet remains poorly characterized and understood due to the enormous hydraulic resistance associated with the nanoconfinement and the resulting minuscule flow rates in such systems. To overcome this problem, here we present a new measurement technique based on capillary flow and a novel hybrid nanochannel design and use it to measure water transport through single 2-D hydrophilic silica nanochannels with heights down to 7 nm. Our results show that silica nanochannels exhibit increased mass flow resistance compared to the classical hydrodynamics prediction. This difference increases with decreasing channel height and reaches 45% in the case of 7 nm nanochannels. This resistance increase is attributed to the formation of a 7-angstrom-thick stagnant hydration layer on the hydrophilic surfaces. By avoiding use of any pressure and flow sensors or any theoretical estimations the hybrid nanochannel scheme enables facile and precise flow measurement through single nanochannels, nanotubes, or nanoporous media and opens the prospect for accurate characterization of both hydrophilic and hydrophobic nanofluidic systems. PMID:27112404

  5. Accurate measurement of liquid transport through nanoscale conduits.

    PubMed

    Alibakhshi, Mohammad Amin; Xie, Quan; Li, Yinxiao; Duan, Chuanhua

    2016-01-01

    Nanoscale liquid transport governs the behaviour of a wide range of nanofluidic systems, yet remains poorly characterized and understood due to the enormous hydraulic resistance associated with the nanoconfinement and the resulting minuscule flow rates in such systems. To overcome this problem, here we present a new measurement technique based on capillary flow and a novel hybrid nanochannel design and use it to measure water transport through single 2-D hydrophilic silica nanochannels with heights down to 7 nm. Our results show that silica nanochannels exhibit increased mass flow resistance compared to the classical hydrodynamics prediction. This difference increases with decreasing channel height and reaches 45% in the case of 7 nm nanochannels. This resistance increase is attributed to the formation of a 7-angstrom-thick stagnant hydration layer on the hydrophilic surfaces. By avoiding use of any pressure and flow sensors or any theoretical estimations the hybrid nanochannel scheme enables facile and precise flow measurement through single nanochannels, nanotubes, or nanoporous media and opens the prospect for accurate characterization of both hydrophilic and hydrophobic nanofluidic systems. PMID:27112404

  6. Absolute measurement of effective atomic number and electron density using dual-energy computed tomography images

    NASA Astrophysics Data System (ADS)

    Kim, Dae-Hong; Kim, Hee-Joung; Lee, Chang-Lae; Cho, Hyo-Min; Park, Hye-Suk; Lee, Seung-Wan; Choi, Yu-Na; Kim, Ye-Seul; Park, Su-Jin

    2012-03-01

    The dual-energy computed tomography (CT) techniques can be adopted to separate the materials having similar Houndsfield Unit (HU) value such as tissues. In the technique, CT image values can be described as effective atomic number and electron density using the dual-energy equation. In this work, we measured effective atomic number and electron density using dual-energy CT images and assessed the image quality in vascular application. For the effective atomic number assessment, the measurements of a Polymethyl methacrylate (PMMA) and water demonstrated small discrepancies of 3.28 % and 5.56 %, respectively. For electron density measurement, the experimental errors of PMMA and water were 7.83 % and 4.00 %, respectively. The trend obtained when comparing the HU values and absolute values such as effective atomic number and electron density demonstrates that the CNR of the HU values is higher than that of the absolute values such as effective atomic number and electron density. With contrast media having low concentration, it is remarkable that the effective atomic number image occasionally has higher CNR values than the HU images. In this study, small discrepancies between the experimental values and known values were obtained. The CNR values provided meaningful results for the absolute measurements in a dual-energy CT technique.

  7. Improving sediment transport measurements in the Erlenbach stream using a moving basket system

    NASA Astrophysics Data System (ADS)

    Rickenmann, Dieter; Turowski, Jens; Hegglin, Ramon; Fritschi, Bruno

    2010-05-01

    In the Erlenbach stream, a prealpine torrent in Switzerland, sediment transport has been monitored for more than 25 years. Sediment transporting flood events in the Erlenbach are typically of short duration with a rapid rise of discharge during summer thunderstorms, thus hampering on-site measurements. On average there are more than 20 bedload transport events per year. Near the confluence with the main valley river, there is a stream gauging station and a sediment retention basin with a capacity of about 2,000 m3. The basin is surveyed at regular intervals and after large flood events. In addition, sediment transport has been continuously monitored with a piezoelectric bedload impact sensor (PBIS) array since 1986. The sensor array is mounted flush with the surface of a check dam immediately upstream of the retention basin. The PBIS system was developed to continuously measure the intensity of bedload transport and its relation to stream discharge. To standardize the sensors, the piezoelectric crystals were replaced by geophones in 2000. The geophone measuring system has also been employed at a number of other streams. In 2008, the measuring system in the Erlenbach stream has been enhanced with an automatic system to obtain bedload samples. Movable, slot-type cubic metal baskets are mounted on a rail at the downstream wall of the large check dam above the retention basin. The metal baskets can be moved automatically and individually into the flow according to flow and bedload transport conditions (i.e. geophone recordings). The basket is stopped at the centerline of the approach flow channel of the overflow section to obtain a sediment sample during a limited time interval. The wire mesh of the basket has a spacing of 10 mm to sample all sediment particles coarser than this size (which is about the limiting grain size detected by the geophones). The weight increase due to the collected sediment is measured by weighing cells located in the basket supporting structure, and this information is used in combination with the geophone recordings to determine when to move a basket laterally away from the flow. The upgraded measuring system allows: (i) to obtain bedload samples over short sampling periods; (ii) to measure the grain size distribution of the transported material and its variation over time and with discharge; (iii) to obtain direct bedload measurements that can be used to improve the understanding of the geophone signal; and (iv) to improve the geophone calibration for the Erlenbach stream. We introduce the new measuring installations, discuss our experience from the first successful automatic sampling operations in summer 2009, and we present first results.

  8. Turbulence Measurements with Hot Wires in High Reynolds Number Boundary Layers

    NASA Astrophysics Data System (ADS)

    Fransson, J. H. M.; Hutchins, N.; Oerlue, R.; Chong, M.

    2009-11-01

    During the last decade there has been a renewed interest in the scaling of turbulent boundary layers, especially with regard to the mean and fluctuation velocity distributions. Recently the ICET team carried out velocity measurements in three different wind tunnels (at KTH, Univ. Melbourne and IIT) for overlapping Reynolds numbers in the range 11,000measurements at similar Reynolds numbers, but with different free stream velocities (due to different development length for the boundary layer in the different wind tunnels). A number of different hot-wire probes and anemometers were used. In addition, accurate and independent skin friction measurements using oil film interferometry have been made to determine the friction velocity (uτ), which is essential for accurate scaling of the data. The peak value of the near wall rms of the streamwise velocity was found to increase with Reynolds number, when scaled with uτ. On the other hand, the skewness and flatness of the streamwise velocity are found to exhibit similarity in the near wall region if measured with sufficiently small (in viscous units) hot-wire probes, indicating a similarity of the probability density distributions independent of Reynolds number. The measurements also provide time series that are used to evaluate the scaling of spectra and other time-domain quantities.

  9. Field measurements of tracer gas transport by barometric pumping

    SciTech Connect

    Lagus, P.L.; McKinnis, W.B.; Hearst, J.R.; Burkhard, N.R.; Smith, C.F.

    1994-07-28

    Vertical gas motions induced by barometric pressure variations can carry radioactive gases out of the rubblized region produced by an underground nuclear explosion, through overburden rock, into the atmosphere. To better quantify transit time and amount of transport, field experiments were conducted at two sites on Pahute Mesa, Kapelli and Tierra, where radioactive gases had been earlier detected in surface cracks. At each site, two tracer gases were injected into the rubblized chimney 300-400 m beneath the surface and their arrival was monitored by concentration measurements in gas samples extracted from shallow collection holes. The first ``active`` tracer was driven by a large quantity of injected air; the second ``passive`` tracer was introduced with minimal gas drive to observe the natural transport by barometric pumping. Kapelli was injected in the fall of 1990, followed by Tierra in the fall of 1991. Data was collected at both sites through the summer of 1993. At both sites, no surface arrival of tracer was observed during the active phase of the experiment despite the injection of several million cubic feet of air, suggesting that cavity pressurization is likely to induce horizontal transport along high permeability layers rather than vertical transport to the surface. In contrast, the vertical pressure gradients associated with barometric pumping brought both tracers to the surface in comparable concentrations within three months at Kapelli, whereas 15 months elapsed before surface arrival at Tierra. At Kapelli, a quasisteady pumping regime was established, with tracer concentrations in effluent gases 1000 times smaller than concentrations thought to exist in the chimney. Tracer concentrations observed at Tierra were typically an order of magnitude smaller. Comparisons with theoretical calculations suggest that the gases are traveling through {approximately}1 millimeter vertical fractures spaced 2 to 4 meters apart. 6 refs., 18 figs., 3 tabs.

  10. Experimental measurements of the laminar separation bubble on an Eppler 387 airfoil at low Reynolds numbers

    NASA Technical Reports Server (NTRS)

    Cole, Gregory M.; Mueller, Thomas J.

    1990-01-01

    An experimental investigation was conducted to measure the flow velocity in the boundary layer of an Eppler 387 airfoil. In particular, the laminar separation bubble that this airfoil exhibits at low Reynolds numbers was the focus. Single component laser Doppler velocimetry data were obtained at a Reynolds number of 100,000 at an angle of attack of 2.0 degree. Static Pressure and flow visualization data for the Eppler 387 airfoil were also obtained. The difficulty in obtaining accurate experimental measurements at low Reynolds numbers is addressed. Laser Doppler velocimetry boundary layer data for the NACA 663-018 airfoil at a Reynolds number of 160,000 and angle of attack of 12 degree is also presented.

  11. Skin Friction and Transition Location Measurement on Supersonic Transport Models

    NASA Technical Reports Server (NTRS)

    Kennelly, Robert A., Jr.; Goodsell, Aga M.; Olsen, Lawrence E. (Technical Monitor)

    2000-01-01

    Flow visualization techniques were used to obtain both qualitative and quantitative skin friction and transition location data in wind tunnel tests performed on two supersonic transport models at Mach 2.40. Oil-film interferometry was useful for verifying boundary layer transition, but careful monitoring of model surface temperatures and systematic examination of the effects of tunnel start-up and shutdown transients will be required to achieve high levels of accuracy for skin friction measurements. A more common technique, use of a subliming solid to reveal transition location, was employed to correct drag measurements to a standard condition of all-turbulent flow on the wing. These corrected data were then analyzed to determine the additional correction required to account for the effect of the boundary layer trip devices.

  12. Direct measurements of transport properties are essential for site characterization

    SciTech Connect

    Wright, J.; Conca, J.L.

    1994-08-01

    Direct measurements of transport parameters on subsurface sediments using, the UFA method provided detailed hydrostratigraphic mapping, and subsurface flux distributions at a mixed-waste disposal site at Hanford. Seven hundred unsaturated conductivity measurements on fifty samples were obtained in only six months total of UFA run time. These data are used to provide realistic information to conceptual models, predictive models and restoration strategies. The UFA instrument consists of an ultracentrifuge with a constant, ultralow flow pump that provides fluid to the sample surface through a rotating seal assembly and microdispersal system. Effluent from the sample is collected in a transparent, volumetrically-calibrated chamber at the bottom of the sample assembly. Using a strobe light, an observer can check the chamber while the sample is being centrifuged. Materials can be run in the UFA as recomposited samples or in situ samples can be subcored directly into the sample UFA chamber.

  13. Backward-facing step measurements at low Reynolds number, Re(sub h)=5000

    NASA Technical Reports Server (NTRS)

    Jovic, Srba; Driver, David M.

    1994-01-01

    An experimental study of the flow over a backward-facing step at low Reynolds number was performed for the purpose of validating a direct numerical simulation (DNS) which was performed by the Stanford/NASA Center for Turbulence Research. Previous experimental data on back step flows were conducted at Reynolds numbers and/or expansion ratios which were significantly different from that of the DNS. The geometry of the experiment and the simulation were duplicated precisely, in an effort to perform a rigorous validation of the DNS. The Reynolds number used in the DNS was Re(sub h)=5100 based on step height, h. This was the maximum possible Reynolds number that could be economically simulated. The boundary layer thickness, d, was approximately 1.0 h in the simulation and the expansion ratio was 1.2. The Reynolds number based on the momentum thickness, Re(sub theta), upstream of the step was 610. All of these parameters were matched experimentally. Experimental results are presented in the form of tables, graphs and a floppy disk (for easy access to the data). An LDV instrument was used to measure mean velocity components and three Reynolds stresses components. In addition, surface pressure and skin friction coefficients were measured. LDV measurements were acquired in a measuring domain which included the recirculating flow region.

  14. Measurements of air pollution emission factors for marine transportation

    NASA Astrophysics Data System (ADS)

    Alföldy, B.; Balzani Lööv, J.; Lagler, F.; Mellqvist, J.; Berg, N.; Beecken, J.; Weststrate, H.; Duyzer, J.; Bencs, L.; Horemans, B.; Cavalli, F.; Putaud, J.-P.; Janssens-Maenhout, G.; Pintér Csordás, A.; Van Grieken, R.; Borowiak, A.; Hjorth, J.

    2012-12-01

    The chemical composition of the plumes of seagoing ships was investigated during a two weeks long measurement campaign in the port of Rotterdam, Hoek van Holland, The Netherlands, in September 2009. Altogether, 497 ships were monitored and a statistical evaluation of emission factors (g kg-1 fuel) was provided. The concerned main atmospheric components were SO2, NO2, NOx and the aerosol particle number. In addition, the elemental and water-soluble ionic composition of the emitted particulate matter was determined. Emission factors were expressed as a function of ship type, power and crankshaft rotational speed. The average SO2 emission factor was found to be roughly half of what is allowed in sulphur emission control areas (16 vs. 30 g kg-1 fuel), and exceedances of this limit were rarely registered. A significant linear relationship was observed between the SO2 and particle number emission factor. The intercept of the regression line, 0.5 × 1016 (kg fuel)-1, gives the average number of particles formed during the burning of 1 kg zero sulphur content fuel, while the slope, 2 × 1018, provides the average number of particles formed with 1 kg sulphur burnt with the fuel. Water-soluble ionic composition analysis of the aerosol samples from the plumes showed that ~144 g of particulate sulphate was emitted from 1 kg sulphur burnt with the fuel. The mass median diameter of sulphate particles estimated from the measurements was ~42 nm.

  15. Velocity measurements of low Reynolds number tube flow using fiber-optic technology

    SciTech Connect

    Bianchi, J.C.

    1993-03-01

    In 1988 Nielsen started work to measure the spatial variability of the mass flux vector being transported in a porous medium. To measure the spatial variability of the mass flux vector, the spatial variability of its components(velocity, concentration) must be measured. Nielsen was successful in measuring the pore level concentration at many different pores and in verifying the assumption that a nonuniform concentration field exists within the mixing zone between two miscible fluids. However, Nielsen was unable to conduct the necessary pore level velocity measurements needed. Nielsen's work is being continued and a probe is being developed that will measure both velocity and concentration components at pore level. The probe is essentially the same probe used to make the pore level concentration measurements with added capabilities needed to make the velocity measurements. This probe has several design variables, dealing primarily with the velocity component, that need further investigation. The research presented in this thesis investigates these parameters by performing experiments in a capillary tube. The tube is a controlled system where the velocity of the fluid can be determined from the volumetric flow rate using Poiseuille's solution for viscous flow. Also, a statistically based relationship between the velocity measured with the probe and the velocity determined from the volumetric flow rate has been developed.

  16. Velocity measurements of low Reynolds number tube flow using fiber-optic technology

    SciTech Connect

    Bianchi, J.C.

    1993-03-01

    In 1988 Nielsen started work to measure the spatial variability of the mass flux vector being transported in a porous medium. To measure the spatial variability of the mass flux vector, the spatial variability of its components(velocity, concentration) must be measured. Nielsen was successful in measuring the pore level concentration at many different pores and in verifying the assumption that a nonuniform concentration field exists within the mixing zone between two miscible fluids. However, Nielsen was unable to conduct the necessary pore level velocity measurements needed. Nielsen`s work is being continued and a probe is being developed that will measure both velocity and concentration components at pore level. The probe is essentially the same probe used to make the pore level concentration measurements with added capabilities needed to make the velocity measurements. This probe has several design variables, dealing primarily with the velocity component, that need further investigation. The research presented in this thesis investigates these parameters by performing experiments in a capillary tube. The tube is a controlled system where the velocity of the fluid can be determined from the volumetric flow rate using Poiseuille`s solution for viscous flow. Also, a statistically based relationship between the velocity measured with the probe and the velocity determined from the volumetric flow rate has been developed.

  17. Mixing measures in non-conservative transport systems

    NASA Astrophysics Data System (ADS)

    Engdahl, N. B.; Fogg, G. E.

    2012-12-01

    Predictions of the fate of reactive solutes in porous media are often made by using the mixing state of the system to determine effective reaction rates. This approach can be useful when the mixing measure accurately characterizes the behavior of the solutes, but, in many cases, the behavior of the mixing measure depends on the reaction system itself. Quantifying mixing is further complicated because the mixing measures often require complete knowledge of the concentration field which is never available in practice. Here we investigate the behavior of the scalar dissipation rate, the dilution index, the variance, and total solute mass in non-conservative transport systems for three component kinetic reactions in large, but finite, monitoring areas. The effects of different reaction rates, mass transfer, mobility, and different initial conditions are considered for these mixing measures. Mass transfer can cause a delay in the time required for the reaction system to reach an equilibrium state, and the magnitude of the delay depends on the mass transfer rate. The effects of this multi-step equilibrium process can manifest contrarily for different mixing measures, and these effects are amplified when the reaction product is immobile. For precipitation-dissolution reactions, the mass transfer rate may depend on the concentration of an immobile precipitate. This process causes sharp transitions in the mixing measures that are the result of a lingering chemical disequilibrium, caused by the concentration dependent mass transfer rates. The immobile domain and the initial conditions can have strong effects on the mixing state for long times, and, without knowledge of immobile concentrations, these effects could easily be attributed to measurement errors.

  18. Correlation of effective atomic number and electron density with attenuation coefficients measured with polychromatic x rays.

    PubMed

    Phelps, M E; Gado, M H; Hoffman, E J

    1975-12-01

    Attenuation coefficients of nine different plastics and water were measured with EMI computed transaxial tomography (CT) and radioisotopic sources with photons of 14 to 136 keV. The EMI values were correlated with physical density, electron density, and atomic number cubed (Z3). The best correlation was obtained with electron density, the exception being the value for water. This descrepancy was explained on the basis of X-dependent photoelectric absorption with verification from monoenergetic measurements. PMID:1188103

  19. Measurements of inertial limit Alfvén wave dispersion for finite perpendicular wave number.

    PubMed

    Kletzing, C A; Thuecks, D J; Skiff, F; Bounds, S R; Vincena, S

    2010-03-01

    Measurements of the dispersion relation for shear Alfvén waves as a function of perpendicular wave number are reported for the inertial regime for which V{A}>V{Te}. The parallel phase velocity and damping are determined as k{ perpendicular} varies and the measurements are compared to theoretical predictions. The comparison shows that the best agreement between theory and experiment is achieved for a fully complex plasma dispersion relation which includes the effects of electron collisions. PMID:20366989

  20. Measurements of Inertial Limit Alfven Wave Dispersion for Finite Perpendicular Wave Number

    SciTech Connect

    Kletzing, C. A.; Thuecks, D. J.; Skiff, F.; Bounds, S. R.; Vincena, S.

    2010-03-05

    Measurements of the dispersion relation for shear Alfven waves as a function of perpendicular wave number are reported for the inertial regime for which V{sub A}>V{sub Te}. The parallel phase velocity and damping are determined as k{sub perpendicular} varies and the measurements are compared to theoretical predictions. The comparison shows that the best agreement between theory and experiment is achieved for a fully complex plasma dispersion relation which includes the effects of electron collisions.

  1. Direct measurement of sub-wavelength interference using thermal light and photon-number-resolved detection

    NASA Astrophysics Data System (ADS)

    Zhai, Yanhua; Becerra, Francisco E.; Fan, Jingyun; Migdall, Alan

    2014-09-01

    We examine thermal light diffracted through a double slit using photon-number-resolved detection to directly measure high-order spatial correlations, and we see sinusoidal modulations of those correlations. The fringe width can, in principal, be made arbitrarily small, and we have experimentally obtained fringe widths as small as 30 nm with 800 nm wavelength light. This extreme sub-wavelength resolution, along with this direct detection technique, offers potential for high precision measurement applications.

  2. Direct measurement of sub-wavelength interference using thermal light and photon-number-resolved detection

    SciTech Connect

    Zhai, Yanhua E-mail: jfan@nist.gov; Fan, Jingyun E-mail: jfan@nist.gov; Migdall, Alan; Becerra, Francisco E.

    2014-09-08

    We examine thermal light diffracted through a double slit using photon-number-resolved detection to directly measure high-order spatial correlations, and we see sinusoidal modulations of those correlations. The fringe width can, in principal, be made arbitrarily small, and we have experimentally obtained fringe widths as small as 30 nm with 800 nm wavelength light. This extreme sub-wavelength resolution, along with this direct detection technique, offers potential for high precision measurement applications.

  3. Measurement of the Copy Number of the Master Quorum-Sensing Regulator of a Bacterial Cell

    NASA Astrophysics Data System (ADS)

    Teng, Shu-Wen; Wang, Yufang; Tu, Kimberly C.; Long, Tao; Mehta, Pankaj; Wingreen, Ned S.; Bassler, Bonnie L.; Ong, N. P.

    2010-05-01

    Quorum sensing is the mechanism by which bacteria communicate and synchronize group behaviors. Quantitative information on parameters such as the copy number of particular quorum-sensing proteins should contribute strongly to understanding how the quorum-sensing network functions. Here we show that the copy number of the master regulator protein LuxR in Vibrio harveyi, can be determined in vivo by exploiting small-number fluctuations of the protein distribution when cells undergo division. When a cell divides, both its volume and LuxR protein copy number N are partitioned with slight asymmetries. We have measured the distribution functions describing the partitioning of the protein fluorescence and the cell volume. The fluorescence distribution is found to narrow systematically as the LuxR population increases while the volume partitioning is unchanged. Analyzing these changes statistically, we have determined that N = 80-135 dimers at low cell density and 575 dimers at high cell density. In addition, we have measured the static distribution of LuxR over a large (3,000) clonal population. Combining the static and time-lapse experiments, we determine the magnitude of the Fano factor of the distribution. This technique has broad applicability as a general, in vivo technique for measuring protein copy number and burst size.

  4. A Reynolds Number Study of Wing Leading-Edge Effects on a Supersonic Transport Model at Mach 0.3

    NASA Technical Reports Server (NTRS)

    Williams, M. Susan; Owens, Lewis R., Jr.; Chu, Julio

    1999-01-01

    A representative supersonic transport design was tested in the National Transonic Facility (NTF) in its original configuration with small-radius leading-edge flaps and also with modified large-radius inboard leading-edge flaps. Aerodynamic data were obtained over a range of Reynolds numbers at a Mach number of 0.3 and angles of attack up to 16 deg. Increasing the radius of the inboard leading-edge flap delayed nose-up pitching moment to a higher lift coefficient. Deflecting the large-radius leading-edge flap produced an overall decrease in lift coefficient and delayed nose-up pitching moment to even higher angles of attack as compared with the undeflected large- radius leading-edge flap. At angles of attack corresponding to the maximum untrimmed lift-to-drag ratio, lift and drag coefficients decreased while lift-to-drag ratio increased with increasing Reynolds number. At an angle of attack of 13.5 deg., the pitching-moment coefficient was nearly constant with increasing Reynolds number for both the small-radius leading-edge flap and the deflected large-radius leading-edge flap. However, the pitching moment coefficient increased with increasing Reynolds number for the undeflected large-radius leading-edge flap above a chord Reynolds number of about 35 x 10 (exp 6).

  5. Experimental measurements of velocity and density statistics in Rayleigh-Taylor instability at High Atwood numbers

    NASA Astrophysics Data System (ADS)

    Ranjan, Devesh; Akula, Bhanesh; Finn, Tom

    2013-11-01

    Velocity statistics are measured in a Rayleigh-Taylor mixing layer at Atwood number 0.6 using the multilayer gas tunnel facility at Texas A&M University, which is capable of achieving mixing Reynolds numbers around 30000. Particle Image Velocimetry (PIV) and hot wire anemometry are used to measure the instantaneous velocities inside the mixing layer. The techniques are validated for small Atwood number and plane mixing layer experiments. The velocity statistics obtained including us ,vs , u ' v ' ̲ , ρ ' v ' ̲ and ρ '2 ̲ are presented and their variation across the mixing layer is also discussed. The probability density functions of the velocities, densities and their spectra are also presented.

  6. Quantitative measurement of electron number in nanosecond and picosecond laser-induced air breakdown

    NASA Astrophysics Data System (ADS)

    Wu, Yue; Sawyer, Jordan C.; Su, Liu; Zhang, Zhili

    2016-05-01

    Here we present quantitative measurements of total electron numbers in laser-induced air breakdown at pressures ranging from atmospheric to 40 barg by 10 ns and 100 ps laser pulses. A quantifiable definition for the laser-induced breakdown threshold is identified by a sharp increase in the measurable total electron numbers via dielectric-calibrated coherent microwave scattering. For the 10 ns laser pulse, the threshold of laser-induced breakdown in atmospheric air is defined as the total electron number of ˜106. This breakdown threshold decreases with an increase of pressure and laser photon energy (shorter wavelength), which is consistent with the theory of initial multiphoton ionization and subsequent avalanche processes. For the 100 ps laser pulse cases, a clear threshold is not present and only marginal pressure effects can be observed, which is due to the short pulse duration leading to stronger multiphoton ionization and minimal collisional avalanche ionization.

  7. Microwave resonance lamp absorption technique for measuring temperature and OH number density in combustion environments

    NASA Technical Reports Server (NTRS)

    Lempert, Walter R.

    1988-01-01

    A simple technique for simultaneous determination of temperature and OH number density is described, along with characteristic results obtained from measurements using a premixed, hydrogen air flat flame burner. The instrumentation is based upon absorption of resonant radiation from a flowing microwave discharge lamp, and is rugged, relatively inexpensive, and very simple to operate.

  8. Measuring Middle Grades Teachers' Understanding of Rational Numbers with the Mixture Rasch Model

    ERIC Educational Resources Information Center

    Izsak, Andrew; Orrill, Chandra Hawley; Cohen, Allan S.; Brown, Rachael Eriksen

    2010-01-01

    We report the development of a multiple-choice instrument that measures the mathematical knowledge needed for teaching arithmetic with fractions, decimals, and proportions. In particular, the instrument emphasizes the knowledge needed to reason about such arithmetic when numbers are embedded in problem situations. We administered our instrument to

  9. Measuring Physical Activity with Pedometers in Older Adults with Intellectual Disability: Reactivity and Number of Days

    ERIC Educational Resources Information Center

    Hilgenkamp, Thessa; Van Wijck, Ruud; Evenhuis, Heleen

    2012-01-01

    The minimum number of days of pedometer monitoring needed to estimate valid average weekly step counts and reactivity was investigated for older adults with intellectual disability. Participants (N = 268) with borderline to severe intellectual disability ages 50 years and older were instructed to wear a pedometer for 14 days. The outcome measure

  10. A Comparison of Two Tree Construction Methods for Obtaining Proximity Measures among Words. Number 47.

    ERIC Educational Resources Information Center

    Rapoport, Amnon

    The prediction that two different methods of constructing linear, tree graphs will yield the same formal structure of semantic space and measurement of word proximity was tested by comparing the distribution of node degree, the distribution of the number of pairs of nodes connected y times, and the distribution of adjective degree in trees…

  11. Multi-bit quantum random number generation by measuring positions of arrival photons

    NASA Astrophysics Data System (ADS)

    Yan, Qiurong; Zhao, Baosheng; Liao, Qinghong; Zhou, Nanrun

    2014-10-01

    We report upon the realization of a novel multi-bit optical quantum random number generator by continuously measuring the arrival positions of photon emitted from a LED using MCP-based WSA photon counting imaging detector. A spatial encoding method is proposed to extract multi-bits random number from the position coordinates of each detected photon. The randomness of bits sequence relies on the intrinsic randomness of the quantum physical processes of photonic emission and subsequent photoelectric conversion. A prototype has been built and the random bit generation rate could reach 8 Mbit/s, with random bit generation efficiency of 16 bits per detected photon. FPGA implementation of Huffman coding is proposed to reduce the bias of raw extracted random bits. The random numbers passed all tests for physical random number generator.

  12. Multi-bit quantum random number generation by measuring positions of arrival photons.

    PubMed

    Yan, Qiurong; Zhao, Baosheng; Liao, Qinghong; Zhou, Nanrun

    2014-10-01

    We report upon the realization of a novel multi-bit optical quantum random number generator by continuously measuring the arrival positions of photon emitted from a LED using MCP-based WSA photon counting imaging detector. A spatial encoding method is proposed to extract multi-bits random number from the position coordinates of each detected photon. The randomness of bits sequence relies on the intrinsic randomness of the quantum physical processes of photonic emission and subsequent photoelectric conversion. A prototype has been built and the random bit generation rate could reach 8 Mbit/s, with random bit generation efficiency of 16 bits per detected photon. FPGA implementation of Huffman coding is proposed to reduce the bias of raw extracted random bits. The random numbers passed all tests for physical random number generator. PMID:25362380

  13. Multi-bit quantum random number generation by measuring positions of arrival photons

    SciTech Connect

    Yan, Qiurong; Zhao, Baosheng; Liao, Qinghong; Zhou, Nanrun

    2014-10-15

    We report upon the realization of a novel multi-bit optical quantum random number generator by continuously measuring the arrival positions of photon emitted from a LED using MCP-based WSA photon counting imaging detector. A spatial encoding method is proposed to extract multi-bits random number from the position coordinates of each detected photon. The randomness of bits sequence relies on the intrinsic randomness of the quantum physical processes of photonic emission and subsequent photoelectric conversion. A prototype has been built and the random bit generation rate could reach 8 Mbit/s, with random bit generation efficiency of 16 bits per detected photon. FPGA implementation of Huffman coding is proposed to reduce the bias of raw extracted random bits. The random numbers passed all tests for physical random number generator.

  14. Complex numbers in chemometrics: examples from multivariate impedance measurements on lipid monolayers.

    PubMed

    Geladi, Paul; Nelson, Andrew; Lindholm-Sethson, Britta

    2007-07-01

    Electrical impedance gives multivariate complex number data as results. Two examples of multivariate electrical impedance data measured on lipid monolayers in different solutions give rise to matrices (16x50 and 38x50) of complex numbers. Multivariate data analysis by principal component analysis (PCA) or singular value decomposition (SVD) can be used for complex data and the necessary equations are given. The scores and loadings obtained are vectors of complex numbers. It is shown that the complex number PCA and SVD are better at concentrating information in a few components than the naïve juxtaposition method and that Argand diagrams can replace score and loading plots. Different concentrations of Magainin and Gramicidin A give different responses and also the role of the electrolyte medium can be studied. An interaction of Gramicidin A in the solution with the monolayer over time can be observed. PMID:17605995

  15. Measuring Hydrodynamics and Sediment Transport in the Swash Zone

    NASA Astrophysics Data System (ADS)

    Puleo, J. A.

    2014-12-01

    The swash zone is the most landward region of the nearshore where wave energy is ultimately dissipated or reflected. It is the most accessible region of the nearshore but is the most challenging for obtaining measurements and performing numerical modeling simulations. The challenging aspects are related to the moving shoreline, rapid changes in water depth, bed level fluctuations, swift, turbulent, direction-reversing flows, large suspended, bed and sheet flow sediment loads, large void fraction, and fluid infiltration and exfiltration from the beach. The major hurdle numerical modelers face is predicting sediment transport rates on a swash-by-swash basis as errors rapidly lead to inaccuracies in simulated morphological evolution. Recent advances in measurement capabilities are now helping to fill gaps in understanding of sediment transport processes and, in turn, improve predictive capability. Newly developed acoustic Doppler profiling velocimeters have allowed for the measurement of hydrodynamics in the direct vicinity of the bed including boundary layer development, bed shear stresses and turbulence dissipation. Bed shear stresses on natural beaches have been estimated at over 20 N/m2; an order of magnitude larger than in the surf zone. Vertical profiles of turbulence dissipation increase near the bed and near the water surface during uprush (shoreward-directed motion) indicating the simultaneous importance of bottom shear and bore-generated turbulence during this phase of motion. Dissipation during backwash (offshore-directed motion) originates at the bed with little influence from fluid motion near the water surface. Other sensors have enabled, for the first time, the measurement of time dependent sheet flow concentrations. Sheet flow thicknesses have been found to exceed 0.03 m under some natural swash zone conditions and concentrations within the mobile sheet flow layer approach the packed bed limit. Sheet flow sediment concentration profiles for varying sheet flow thicknesses are self-similar when scaled by the layer thickness. Example data from field and large-scale laboratory experiments will be presented to show the fidelity of the new measurements and used to highlight continued difficulties encountered in trying to understand the physical processes occurring in the swash zone.

  16. Quantitative measurement of the nanoparticle size and number concentration from liquid suspensions by atomic force microscopy.

    PubMed

    Baalousha, M; Prasad, A; Lead, J R

    2014-05-01

    Microscopy techniques are indispensable to the nanoanalytical toolbox and can provide accurate information on the number size distribution and number concentration of nanoparticles (NPs) at low concentrations (ca. ppt to ppb range) and small sizes (ca. <20 nm). However, the high capabilities of microscopy techniques are limited by the traditional sample preparation based on drying a small volume of suspension of NPs on a microscopy substrate. This method is limited by low recovery of NPs (ca. <10%), formation of aggregates during the drying process, and thus, the complete misrepresentation of the NP suspensions under consideration. This paper presents a validated quantitative sampling technique for atomic force microscopy (AFM) that overcomes the above-mentioned shortcomings and allows full recovery and representativeness of the NPs under consideration by forcing the NPs into the substrate via ultracentrifugation and strongly attaches the NPs to the substrate by surface functionalization of the substrate or by adding cations to the NP suspension. The high efficiency of the analysis is demonstrated by the uniformity of the NP distribution on the substrate (that is low variability between the number of NPs counted on different images on different areas of the substrate), the high recovery of the NPs up to 71%) and the good correlation (R > 0.95) between the mass and number concentrations. Therefore, for the first time, we developed a validated quantitative sampling technique that enables the use of the full capabilities of microscopy tools to quantitatively and accurately determine the number size distribution and number concentration of NPs at environmentally relevant low concentrations (i.e. 0.34-100 ppb). This approach is of high environmental relevance and can be applied widely in environmental nanoscience and nanotoxicology for (i) measuring the number concentration dose in nanotoxicological studies and (ii) accurately measuring the number size distribution of NPs; both are key requirements for the implementation of the European Commission recommendation for definition of nanomaterials. PMID:24668140

  17. Transport measurements on monolayer and few-layer WSe2

    NASA Astrophysics Data System (ADS)

    Palomaki, Tauno; Zhao, Wenjin; Finney, Joe; Fei, Zaiyao; Nguyen, Paul; McKay, Frank; Cobden, David

    The behavior of the electrical contacts often dominates transport measurements in mono and few-layer transition metal dichalcogenide (TMD) devices. Creating good contacts for some TMDs is particularly challenging since the fabrication procedure should prevent the TMD from oxidizing or chemically interacting with the contacts. In this talk, we discuss our progress on creating mono and few-layer WSe2 devices with both good electrical contacts and minimal effects from the substrate, polymer contamination, oxidation and other chemistry. For example, we have developed a technique for encapsulating metallic contacts and WSe2 flakes together in hexagonal boron nitride with multiple gates to separate and control the contributions from the channel and the Schottky barriers at the contacts. Research supported in part by Samsung GRO grant US 040814

  18. Mean Flow Measurements with Hot Wires in High Reynolds Number Boundary Layers

    NASA Astrophysics Data System (ADS)

    Duncan, R.; Hutchins, N.; Segalini, A.; Monty, J.

    2009-11-01

    Mean flow measurements of high Reynolds number, Zero Pressure Gradient (ZPG) turbulent boundary layers are presented from the ICET data set using hot wire anemometry. The measurements were performed at momentum thickness Reynolds numbers in the range from 11,000 to 70,000, and compared to Pitot probe measurements at the same conditions. Various wire diameters, sensing lengths, probe designs and construction techniques are used, as well as different anemometer setups, in each of the facilities. Mean flow similarity between the three facilities is shown to be well within expected experimental uncertainty and ZPG layer manifestations, both when examining mean velocity profiles and integral parameters. The results reinforce the need for accurate near wall velocity and position measurements, as well as consistent analysis of physical and instrumentation biases. Various approaches are used to determine parameters such as the shape factor, the logarithmic overlap-region parameters, and the wake or outer flow parameters. Parameters extracted from the hot-wire profiles and those based on Pitot probe data are also compared and discussed in light of past experience with both instruments in different wall bounded flow experiments. Finally, consistency of the results is examined between the profile data and the skin friction behavior with Reynolds number, as measured by oil film interferometry.

  19. Nanoscale electron transport measurements of immobilized cytochrome P450 proteins

    NASA Astrophysics Data System (ADS)

    Bostick, Christopher D.; Flora, Darcy R.; Gannett, Peter M.; Tracy, Timothy S.; Lederman, David

    2015-04-01

    Gold nanopillars, functionalized with an organic self-assembled monolayer, can be used to measure the electrical conductance properties of immobilized proteins without aggregation. Measurements of the conductance of nanopillars with cytochrome P450 2C9 (CYP2C9) proteins using conducting probe atomic force microscopy demonstrate that a correlation exists between the energy barrier height between hopping sites and CYP2C9 metabolic activity. Measurements performed as a function of tip force indicate that, when subjected to a large force, the protein is more stable in the presence of a substrate. This agrees with the hypothesis that substrate entry into the active site helps to stabilize the enzyme. The relative distance between hopping sites also increases with increasing force, possibly because protein functional groups responsible for electron transport (ETp) depend on the structure of the protein. The inhibitor sulfaphenazole, in addition to the previously studied aniline, increased the barrier height for electron transfer and thereby makes CYP2C9 reduction more difficult and inhibits metabolism. This suggests that P450 Type II binders may decrease the ease of ETp processes in the enzyme, in addition to occupying the active site.

  20. Nanoscale electron transport measurements of immobilized cytochrome P450 proteins.

    PubMed

    Bostick, Christopher D; Flora, Darcy R; Gannett, Peter M; Tracy, Timothy S; Lederman, David

    2015-04-17

    Gold nanopillars, functionalized with an organic self-assembled monolayer, can be used to measure the electrical conductance properties of immobilized proteins without aggregation. Measurements of the conductance of nanopillars with cytochrome P450 2C9 (CYP2C9) proteins using conducting probe atomic force microscopy demonstrate that a correlation exists between the energy barrier height between hopping sites and CYP2C9 metabolic activity. Measurements performed as a function of tip force indicate that, when subjected to a large force, the protein is more stable in the presence of a substrate. This agrees with the hypothesis that substrate entry into the active site helps to stabilize the enzyme. The relative distance between hopping sites also increases with increasing force, possibly because protein functional groups responsible for electron transport (ETp) depend on the structure of the protein. The inhibitor sulfaphenazole, in addition to the previously studied aniline, increased the barrier height for electron transfer and thereby makes CYP2C9 reduction more difficult and inhibits metabolism. This suggests that P450 Type II binders may decrease the ease of ETp processes in the enzyme, in addition to occupying the active site. PMID:25804257

  1. Spectroscopic measurements of plasma temperatures and electron number density in a uranium hollow cathode discharge lamp

    NASA Astrophysics Data System (ADS)

    Shah, M. L.; Suri, B. M.; Gupta, G. P.

    2015-01-01

    The plasma parameters including neutral species temperature, atomic excitation temperature and electron number density in a see-through type, homemade uranium hollow cathode discharge lamp with neon as a buffer gas have been investigated using optical emission spectroscopic techniques. The neutral species temperature has been measured using the Doppler broadening of a neon atomic spectral line. The atomic excitation temperature has been measured using the Boltzmann plot method utilizing uranium atomic spectral lines. The electron number density has been determined from the Saha-Boltzmann equation utilizing uranium atomic and ionic spectral lines. To the best of our knowledge, all these three plasma parameters are simultaneously measured for the first time in a uranium hollow cathode discharge lamp.

  2. Loss-tolerant measurement-device-independent quantum random number generation

    NASA Astrophysics Data System (ADS)

    Cao, Zhu; Zhou, Hongyi; Ma, Xiongfeng

    2015-12-01

    Quantum random number generators (QRNGs) output genuine random numbers based upon the uncertainty principle. A QRNG contains two parts in general—a randomness source and a readout detector. How to remove detector imperfections has been one of the most important questions in practical randomness generation. We propose a simple solution, measurement-device-independent QRNG, which not only removes all detector side channels but is robust against losses. In contrast to previous fully device-independent QRNGs, our scheme does not require high detector efficiency or nonlocality tests. Simulations show that our protocol can be implemented efficiently with a practical coherent state laser and other standard optical components. The security analysis of our QRNG consists mainly of two parts: measurement tomography and randomness quantification, where several new techniques are developed to characterize the randomness associated with a positive-operator valued measure.

  3. Measurements of the turbulence structure downstream of a tube bundle at high Reynolds numbers

    SciTech Connect

    Karnik, U. )

    1994-12-01

    Mean and turbulent velocity profiles are measured in natural gas at a static pressure of approximately 5,200 kPa and a Reynolds number of around 7 [times] 10[sup 6]. These measurements are obtained by conventional hot film anemometry suitably modified for use in a natural gas environment. Measurements are taken in a 102.26 mm nominal diameter pipe following a development length of around 76D. The mean velocity profile and the turbulence intensities at this location are typical for a fully developed pipe flow. Further, measurements downstream of a 19 tube bundle flow conditioner are also presented. The tube bundle is traversed downstream of a 90 degree, long radius (r = 1.5D) elbow and the measurements are taken at 19D downstream of the elbow exit. Measurements include those of the axial mean and turbulent velocities and the integral length scales. It is found that the decay of turbulence is slower and the magnitude of the length scale is smaller in comparison to measurements at lower Reynolds numbers. Orifice meter comparisons, performed in a 19D test section (meter run), confirm earlier findings that turbulence is one of the factors that affects orifice meter accuracy.

  4. A collision-based model for measuring bedload transport from the seismic waves generated by rivers

    NASA Astrophysics Data System (ADS)

    Roth, D. L.; Finnegan, N. J.; Brodsky, E. E.; Stark, C. P.

    2011-12-01

    Accurately predicting rates of coarse sediment transport in river channels is a central goal of fluvial geomorphology and civil engineering. However, it is difficult to evaluate sediment transport and bedrock abrasion models in large rivers because quantitative measures of bedload transport are labor intensive and often dangerous to obtain in floods. Two recent studies show that the amplitude of seismic waves near rivers may record bedload flux, indicating that seismometers near rivers provide a potential means of monitoring bedload transport. In an effort to better interpret seismic waves generated by rivers, we seek a relationship between the variables governing bedload transport and seismic waves. Our approach relies on the fact that elastic waves are generated when momentum is transferred to the bed during a bedload particle impact. For an impacting particle of known mass and velocity, the momentum transfer can be computed from Hertzian impact theory. Here we combine analytic results based on Hertzian and elastic wave theories with empirical equations developed to describe the ballistics of bedload particles in terms of fluid shear stress and grain size. From this synthesis we arrive at a semi-analytic expression that predicts how the characteristic frequencies and amplitudes of seismic waves generated from saltating bedload particles should scale with fluid shear stress, grain size, and coarse sediment flux. Preliminary tests of our predictions using previously published and newly acquired laboratory data indicate that seismic signals near rivers can record information about the size, velocity and number of particles impacting the bed. Additionally, our analytical results help identify bedload transport events in seismic data collected along the Chijiawan River in Taiwan. Here the river is evolving rapidly in response to a dam removal - resulting in predictable changes in bedload transport efficiency in time and space that we can compare to local seismic data.

  5. Integrating field measurements with flume experiments for analysing fluvial bedload transport in steep mountain streams

    NASA Astrophysics Data System (ADS)

    Beylich, A. A.; Laute, K.; Liermann, S.

    2012-04-01

    Fluvial bedload transport has high importance within sediment budgets of steep catchments and steep mountain streams. It is also of crucial importance as headwater catchments and steep mountain streams can be relevant sediment sources for lowland river systems. Measured under comparable conditions of discharge, rates of fluvial bedload transport can differ by up to one order of magnitude, which is due to the irregular nature of sediment movement. Bedload transport at a defined site depends on factors such as local flow conditions, bed material composition and amount of sediment supply from upstream sources. Irregular deviations from mean rates of bedload transport can be caused by sporadic inputs of material from hillslopes. Permafrost degradation and shifts in ground frost regimes as caused by climate change can lead to increased frequencies and intensities of mass movements on slopes including the increased frequency of rock fall events. By the destabilisation of slope systems higher amounts of sediment are available from a larger number of activated sediment sources. At the same time, a higher frequency of extreme rainfall events and thermally determined runoff-peaks from glacier-fed systems is leading to an increased number of peak runoff events showing a high transport competence with significant fluvial bedload transport. A better general understanding of the exact mechanisms and the dynamics of fluvial bedload transport is essential for the further improvement of river engineering management and hazard mitigation projects. Since 2004, extended and interdisciplinary field investigations on fluvial bedload transport using a novel combination of methods and techniques have been performed in a number of selected stream segments in supply-limited fluvial systems in the inner Nordfjord (Erdalen and Bødalen drainage basins) in western Norway. Field studies include (i) continuous channel discharge monitoring, (ii) frequently repeated surveys of channel morphometry and granulometric analyses, (iii) different tracer techniques (painted stones, magnetic tracers), (iv) Helley-Smith and other basket measurements, (v) horizontally installed impact sensors, (vi) underwater video filming, and (vii) extended biofilm analyses, including also controlled biofilm growing experiments with fixed baskets in selected channels. In addition, field studies with horizontally installed impact sensors were also carried out in selected transport-limited fluvial systems in the Coast Mountains of British Columbia (Canada) in 2010 and 2011. The extended field studies are integrated with advanced flume experiments which were carried out in 2010 and 2011 at the Department of Geography at the University of British Columbia (UBC), Canada for calibration of field measurements. As a key achievement, the entire range of different bedload component grain sizes can be covered by the applied combination of techniques, and the presented integration of interdisciplinary field measurements with flume experiments appears to be a useful approach to study mechanisms, controlling factors and rates of fluvial bedload transport in steep mountain streams.

  6. Effect of Reynolds number variation on aerodynamics of a hydrogen-fueled transport concept at Mach 6

    NASA Technical Reports Server (NTRS)

    Penland, Jim A.; Marcum, Don C., Jr.

    1987-01-01

    Two separate tests have been made on the same blended wing-body hydrogen-fueled transport model at a Mach number of about 6 and a range of Reynolds number (based on theoretical body length) of 1.577 to 55.36 X 10 to the 6th power. The results of these tests, made in a conventional hypersonic blowdown tunnel and a hypersonic shock tunnel, are presented through a range of angle of attack from -1 to 8 deg, with an extended study at a constant angle of attack of 3 deg. The model boundary layer flow appeared to be predominately turbulent except for the low Reynolds number shock tunnel tests. Model wall temperatures varied considerably; the blowdown tunnel varied from about 255 F to 340 F, whereas the shock tunnel had a constant 70 F model wall temperature. The experimental normal-force coefficients were essentially independent of Reynolds number. A current theoretical computer program was used to study the effect of Reynolds number. Theoretical predictions of normal-force coefficients were good, particularly at anticipated cruise angles of attack, that is 2 to 5 deg. Axial-force coefficients were generally underestimated for the turbulent skin friction conditions, and pitching-moment coefficients could not be predicted reliably.

  7. Evaluating quantitative methods for measuring plasmid copy numbers in single cells

    PubMed Central

    Tal, Shay; Paulsson, Johan

    2013-01-01

    The life of plasmids is a constant battle against fluctuations: failing to correct copy number fluctuations can increase the plasmid loss rate by many orders of magnitude, as can a failure to more evenly divide the copies between daughters at cell division. Plasmids are therefore long-standing model systems for stochastic processes in cells, much thanks to the efforts of Kurt Nordström to whose memory this issue is dedicated. Here we analyze a range of experimental methods for measuring plasmid copy numbers in single cells, focusing on challenges, trade-offs and necessary experimental controls. In particular we analyze published and unpublished strategies to infer copy numbers from expression of plasmid-encoded reporters, direct labeling of plasmids with fluorescent probes or DNA binding proteins fused to fluorescent reporters, PCR based methods applied to single cell lysates, and plasmid-specific replication arrest. We conclude that no method currently exists to measure plasmid copy numbers in single cells, and that most methods instead inadvertently measure various types of experimental noise. We also discuss how accurate methods can be developed. PMID:22305922

  8. Development of pressure sensitive molecular film applicable to pressure measurement for high Knudsen number flows

    NASA Astrophysics Data System (ADS)

    Matsuda, Yu; Mori, Hideo; Niimi, Tomohide; Uenishi, Hiroyuki; Hirako, Madoka

    2007-04-01

    Experimental analyses of thermo-fluid phenomena of micro- and nano-flows with high Knudsen number need the measurement techniques based on interaction of atoms or molecules with photons. The pressure-sensitive paint (PSP) technique has potential as a diagnostic tool for pressure measurement in the high Knudsen number regime because it works as a so-called “molecular sensor”. However, application of PSP to micro devices is very difficult because the conventional PSP is too thick owing to the use of polymer binder and does not have sufficient spatial resolution for pressure measurement of micro-flows. In this study, we have adopted the Langmuir-Blodgett (LB) technique to fabricate pressure sensitive molecular films (PSMFs) using Pd(II) Octaethylporphine (PdOEP) and Pd(II) Mesoporphyrin IX (PdMP) to resolve ordinary PSPs problems, and have tested these PSMFs to evaluate the feasibility of the pressure measurement around micro-devices. It is clarified that the PSMF composed of PdMP has higher sensitivity than that of PdOEP. Since it is also considered that the sensitivity of PSMFs can be increased by introducing arachidic acid (AA) as spacer molecules of LB films to prevent the aggregation of luminescent molecules, we have produced PSMFs with several molar ratio of PdMP to AA. At the most suitable ratio, the PSMF has high sensitivity in the low pressure region with high Knudsen number, even if the amount of the luminescent molecules in the PSMF layer is smaller than that in conventional PSPs. This result indicates that the PSMF is feasible to measure the pressure in high Knudsen number flows such as micro-flows.

  9. Thermal transport measurements in high-energy-density matter

    NASA Astrophysics Data System (ADS)

    Ping, Yuan

    2015-11-01

    Thermal conductivity is one of the most fundamental physical properties of matter. It determines the heat transport rate and has an enormous impact on a variety of mechanical, electrical, chemical, and nuclear systems. Thermal conduction is important in high energy density (HED) matter such as laboratory fusion plasmas, planetary cores, compact stars, and other celestial objects. Examples are in the ablation and instability growth in inertial confinement fusion (ICF) capsules, in energy loss from ICF hot spot, and in the evolution of Earth's core-mantle boundary. Despite the importance of thermal conductivity in HED systems, experimental measurements under relevant conditions are scarce and challenging. We have developed a method of differential heating for thermal conductivity measurements. In this talk, experimental designs will be described for four different platforms: optical laser heating, proton heating, laser-generated x-ray heating and XFEL heating. Data from various facilities will be presented and comparison with models will be discussed. This work was performed under DOE contract DE-AC52-07NA27344 with support from OFES Early Career program and LLNL LDRD program.

  10. Method measuring oxygen tension and transport within subcutaneous devices.

    PubMed

    Weidling, John; Sameni, Sara; Lakey, Jonathan R T; Botvinick, Elliot

    2014-08-01

    Cellular therapies hold promise to replace the implantation of whole organs in the treatment of disease. For most cell types, in vivo viability depends on oxygen delivery to avoid the toxic effects of hypoxia. A promising approach is the in situ vascularization of implantable devices which can mediate hypoxia and improve both the lifetime and utility of implanted cells and tissues. Although mathematical models and bulk measurements of oxygenation in surrounding tissue have been used to estimate oxygenation within devices, such estimates are insufficient in determining if supplied oxygen is sufficient for the entire thickness of the implanted cells and tissues. We have developed a technique in which oxygen-sensitive microparticles (OSMs) are incorporated into the volume of subcutaneously implantable devices. Oxygen partial pressure within these devices can be measured directly in vivo by an optical probe placed on the skin surface. As validation, OSMs have been incorporated into alginate beads, commonly used as immunoisolation devices to encapsulate pancreatic islet cells. Alginate beads were implanted into the subcutaneous space of SpragueDawley rats. Oxygen transport through beads was characterized from dynamic OSM signals in response to changes in inhaled oxygen. Changes in oxygen dynamics over days demonstrate the utility of our technology. PMID:25162910

  11. Tabulated pressure measurements on an executive-type jet transport model with a supercritical wing

    NASA Technical Reports Server (NTRS)

    Bartlett, D. W.

    1975-01-01

    A 1/9 scale model of an existing executive type jet transport refitted with a supercritical wing was tested on in the 8 foot transonic pressure tunnel. The supercritical wing had the same sweep as the original airplane wing but had maximum thickness chord ratios 33 percent larger at the mean geometric chord and almost 50 percent larger at the wing-fuselage juncture. Wing pressure distributions and fuselage pressure distributions in the vicinity of the left nacelle were measured at Mach numbers from 0.25 to 0.90 at angles of attack that generally varied from -2 deg to 10 deg. Results are presented in tabular form without analysis.

  12. Measuring the number and spacing of molecular motors propelling a gliding microtubule.

    PubMed

    Fallesen, Todd L; Macosko, Jed C; Holzwarth, G

    2011-01-01

    The molecular motor gliding assay, in which a microtubule or other filament moves across a surface coated with motors, has provided much insight into how molecular motors work. The kinesin-microtubule system is also a strong candidate for the job of nanoparticle transporter in nanotechnology devices. In most cases, several motors transport each filament. Each motor serves both to bind the microtubule to a stationary surface and to propel the microtubule along the surface. By applying a uniform transverse force of 4-19 pN to a superparamagnetic bead attached to the trailing end of the microtubule, we have measured the distance d between binding points (motors). The average value of d was determined as a function of motor surface density ?. The measurements agree well with the scaling model of Duke, Holy, and Liebler, which predicts that (d)~?(-2/5) if 0.05???20??m(-2) [Phys. Rev. Lett. 74, 330 (1995)]. The distribution of d fits an extension of the model. The radius of curvature of a microtubule bent at a binding point by the force of the magnetic bead was ?1 ?m, 5000-fold smaller than the radius of curvature of microtubules subjected only to thermal forces. This is evidence that at these points of high bending stress, generated by the force on the magnetic bead, the microtubule is in the more flexible state of a two-state model of microtubule bending proposed by Heussinger, Schller, and Frey [Phys. Rev. E 81, 021904 (2010)]. PMID:21405724

  13. Measurement of plasmalemmal dopamine transport, vesicular dopamine transport, and K(+)-stimulated dopamine release in frozen rat brain tissue.

    PubMed

    Volz, Trent J; Farnsworth, Sarah J; Hanson, Glen R; Fleckenstein, Annette E

    2009-06-15

    This report describes experiments designed to (1) establish the specificity of dopamine (DA) transporter (DAT)-mediated plasmalemmal DA transport, vesicular monoamine transporter-2 (VMAT-2)-mediated vesicular DA transport, and K+-stimulated DA release in samples prepared from frozen rat striata, and (2) characterize the time-course of the effects of freezing on these processes. The procedure described herein uses a simple method of freezing brain tissue (first cooling in ice-cold buffer and then freezing at -80 degrees C) that allows for the storage of rat striata followed by the assay of DA transport and K+-stimulated DA release using rotating disk electrode voltammetry. Plasmalemmal DA transport into samples prepared from frozen striata was blocked by the DAT inhibitor, cocaine, and vesicular DA transport was blocked by the VMAT-2 inhibitor, dihydrotetrabenazine. Additionally, K+-stimulated DA release was Ca+2-dependent. Freezing decreases DAT-mediated DA transport, VMAT-2-mediated DA transport, and K+-stimulated DA release. However activity is still measurable even after 3 weeks of storage. These results suggest that rat striata retain some DA transport and DA release activity even when stored frozen for a few weeks. Frozen storage of rat striata may thus be valuable for experiments requiring lengthy assays, the accumulation of material, or the transport of samples from one laboratory to another for analysis. These results may also be applicable to the study of frozen human brain tissue. PMID:19464519

  14. DNA copy number concentration measured by digital and droplet digital quantitative PCR using certified reference materials.

    PubMed

    Corbisier, Philippe; Pinheiro, Leonardo; Mazoua, Stphane; Kortekaas, Anne-Marie; Chung, Pui Yan Jenny; Gerganova, Tsvetelina; Roebben, Gert; Emons, Hendrik; Emslie, Kerry

    2015-03-01

    The value assignment for properties of six certified reference materials (ERM-AD623a-f), each containing a plasmid DNA solution ranging from 1 million to 10 copies per ?L, by using digital PCR (dPCR) with the BioMark HD System (Fluidigm) has been verified by applying droplet digital PCR (ddPCR) using the QX100 system (Bio-Rad). One of the critical factors in the measurement of copy number concentrations by digital PCR is the partition volume. Therefore, we determined the average droplet volume by optical microscopy, revealing an average droplet volume that is 8% smaller than the droplet volume used as the defined parameter in the QuantaSoft software version 1.3.2.0 (Bio-Rad) to calculate the copy number concentration. This observation explains why copy number concentrations estimated with ddPCR and using an average droplet volume predefined in the QuantaSoft software were systematically lower than those measured by dPCR, creating a significant bias between the values obtained by these two techniques. The difference was not significant anymore when the measured droplet volume of 0.834nL was used to estimate copy number concentrations. A new version of QuantaSoft software (version 1.6.6.0320), which has since been released with Bio-Rad's new QX200 systems and QX100 upgrades, uses a droplet volume of 0.85nL as a defined parameter to calculate copy number concentration. PMID:25600685

  15. 40 CFR 88.307-94 - Exemption from temporal transportation control measures for CFFVs.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 20 2011-07-01 2011-07-01 false Exemption from temporal transportation... Exemption from temporal transportation control measures for CFFVs. (a) States with covered areas shall... credits under § 88.304-94(c) from transportation control measures (TCMs) existing wholly or partially...

  16. 40 CFR 88.307-94 - Exemption from temporal transportation control measures for CFFVs.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Exemption from temporal transportation... Exemption from temporal transportation control measures for CFFVs. (a) States with covered areas shall... credits under § 88.304-94(c) from transportation control measures (TCMs) existing wholly or partially...

  17. High-speed quantum-random number generation by continuous measurement of arrival time of photons

    SciTech Connect

    Yan, Qiurong; Zhao, Baosheng; Hua, Zhang; Liao, Qinghong; Yang, Hao

    2015-07-15

    We demonstrate a novel high speed and multi-bit optical quantum random number generator by continuously measuring arrival time of photons with a common starting point. To obtain the unbiased and post-processing free random bits, the measured photon arrival time is converted into the sum of integral multiple of a fixed period and a phase time. Theoretical and experimental results show that the phase time is an independent and uniform random variable. A random bit extraction method by encoding the phase time is proposed. An experimental setup has been built and the unbiased random bit generation rate could reach 128 Mb/s, with random bit generation efficiency of 8 bits per detected photon. The random numbers passed all tests in the statistical test suite.

  18. Cloud Liquid Water, Mean Droplet Radius and Number Density Measurements Using a Raman Lidar

    NASA Technical Reports Server (NTRS)

    Whiteman, David N.; Melfi, S. Harvey

    1999-01-01

    A new technique for measuring cloud liquid water, mean droplet radius and droplet number density is outlined. The technique is based on simultaneously measuring Raman and Mie scattering from cloud liquid droplets using a Raman lidar. Laboratory experiments on liquid micro-spheres have shown that the intensity of Raman scattering is proportional to the amount of liquid present in the spheres. This fact is used as a constraint on calculated Mie intensity assuming a gamma function particle size distribution. The resulting retrieval technique is shown to give stable solutions with no false minima. It is tested using Raman lidar data where the liquid water signal was seen as an enhancement to the water vapor signal. The general relationship of retrieved average radius and number density is consistent with traditional cloud physics models. Sensitivity to the assumed maximum cloud liquid water amount and the water vapor mixing ratio calibration are tested. Improvements to the technique are suggested.

  19. In-flight surface-flow measurements on a subsonic transport high-lift flap system

    NASA Technical Reports Server (NTRS)

    Yip, Long P.; Vijgen, Paul M. H. W.; Hardin, Jay D.

    1992-01-01

    As part of a multiphased program for subsonic transport high-lift flight research, flight tests were conducted on the Transport Systems Research Vehicle (B737-100 aircraft) at the NASA Langley Research Center, to obtain detailed flow characteristics of the high-lift flap system for correlation with computational and wind-tunnel investigations. Pressure distributions, skin friction, and flow-visualization measurements were made on a triple-slotted flap system for a range of flap deflections, chord Reynolds numbers (10 to 21 million), and Mach numbers (0.16 to 0.36). Experimental test results are given for representative flap settings indicating flow separation on the fore-flap element for the largest flap deflection. Comparisons of the in-flight flow measurements were made with predictions from available viscous multielement computational methods modified with simple-sweep theory. Computational results overpredicted the experimentally measured pressures, particularly in the case involving separation of the fore lap, indicating the need for better modeling of confluent boundary layers and three-dimensional sweep effects.

  20. Photon-number statistics of twin beams: Self-consistent measurement, reconstruction, and properties

    SciTech Connect

    Peřina, Jan Jr.; Haderka, Ondřej; Michálek, Václav

    2014-12-04

    A method for the determination of photon-number statistics of twin beams using the joint signal-idler photocount statistics obtained by an iCCD camera is described. It also provides absolute quantum detection efficiency of the camera. Using the measured photocount statistics, quasi-distributions of integrated intensities are obtained. They attain negative values occurring in characteristic strips an a consequence of pairing of photons in twin beams.

  1. Relationship between Objectively Measured Transportation Behaviors and Health Characteristics in Older Adults.

    PubMed

    Takemoto, Michelle; Carlson, Jordan A; Moran, Kevin; Godbole, Suneeta; Crist, Katie; Kerr, Jacqueline

    2015-11-01

    This study used objective Global Positioning Systems (GPS) to investigate the relationship between pedestrian and vehicle trips to physical, cognitive, and psychological functioning in older adults living in retirement communities. Older adults (N = 279; mean age = 83 ± 6 years) wore a GPS and accelerometer for 6 days. Participants completed standard health measures. The Personal Activity and Location Measurement System (PALMS) was used to calculate the average daily number of trips, distance, and minutes traveled for pedestrian and vehicle trips from the combined GPS and accelerometer data. Linear mixed effects regression models explored relationships between these transportation variables and physical, psychological and cognitive functioning. Number, distance, and minutes of pedestrian trips were positively associated with physical and psychological functioning but not cognitive functioning. Number of vehicle trips was negatively associated with fear of falls; there were no other associations between the vehicle trip variables and functioning. Vehicle travel did not appear to be related to functioning in older adults in retirement communities except that fear of falling was related to number of vehicle trips. Pedestrian trips had moderate associations with multiple physical and psychological functioning measures, supporting a link between walking and many aspects of health in older adults. PMID:26528999

  2. Relationship between Objectively Measured Transportation Behaviors and Health Characteristics in Older Adults

    PubMed Central

    Takemoto, Michelle; Carlson, Jordan A.; Moran, Kevin; Godbole, Suneeta; Crist, Katie; Kerr, Jacqueline

    2015-01-01

    This study used objective Global Positioning Systems (GPS) to investigate the relationship between pedestrian and vehicle trips to physical, cognitive, and psychological functioning in older adults living in retirement communities. Older adults (N = 279; mean age = 83 ± 6 years) wore a GPS and accelerometer for 6 days. Participants completed standard health measures. The Personal Activity and Location Measurement System (PALMS) was used to calculate the average daily number of trips, distance, and minutes traveled for pedestrian and vehicle trips from the combined GPS and accelerometer data. Linear mixed effects regression models explored relationships between these transportation variables and physical, psychological and cognitive functioning. Number, distance, and minutes of pedestrian trips were positively associated with physical and psychological functioning but not cognitive functioning. Number of vehicle trips was negatively associated with fear of falls; there were no other associations between the vehicle trip variables and functioning. Vehicle travel did not appear to be related to functioning in older adults in retirement communities except that fear of falling was related to number of vehicle trips. Pedestrian trips had moderate associations with multiple physical and psychological functioning measures, supporting a link between walking and many aspects of health in older adults. PMID:26528999

  3. Measurement of High Reynolds Number Near-Field Turbulent Sphere Wakes under Stratified Conditions

    NASA Astrophysics Data System (ADS)

    Kalumuck, Kenneth; Brandt, Alan; Decker, Kirk; Shipley, Kara

    2015-11-01

    To characterize the near-field of a stratified wake at Reynolds numbers, Re = 2 x 105 - 106, experiments were conducted with a large diameter (0.5 m) sphere towed through a thermally stratified fresh water lake. Stratification produced BV frequencies, N, up to 0.07/s (42 cph) resulting in Froude numbers F = U/ND >= 15. The submerged sphere and associated instrumentation including two Acoustic Doppler Velocimeters (ADVs) and an array of fast response thermistors were affixed to a common frame towed over a range of speeds. Three components of the instantaneous wake velocities were obtained simultaneously at two cross-wake locations with the ADVs while density fluctuations were inferred from temperature measurements made by the thermistors. These measurements were used to determine the mean, rms, and spectra of all three components of the turbulent velocity field and density fluctuations at multiple locations. The turbulence power spectra follow the expected -5/3 slope with wavenumber. Existing stratified near-field wake data for spheres are for Re =104 and less, and only a very limited set of data under unstratified conditions exists at these large values of Re. Those data are primarily measurements of the sphere drag, surface pressure distribution, and separation rather than in wake turbulence. Advances in CFD modeling have enabled simulations at these high Reynolds numbers without quantitative data available for validation. Sponsored by ONR Turbulence and Wakes program.

  4. The generation of 68 Gbps quantum random number by measuring laser phase fluctuations

    SciTech Connect

    Nie, You-Qi; Liu, Yang; Zhang, Jun Pan, Jian-Wei; Huang, Leilei; Payne, Frank

    2015-06-15

    The speed of a quantum random number generator is essential for practical applications, such as high-speed quantum key distribution systems. Here, we push the speed of a quantum random number generator to 68 Gbps by operating a laser around its threshold level. To achieve the rate, not only high-speed photodetector and high sampling rate are needed but also a very stable interferometer is required. A practical interferometer with active feedback instead of common temperature control is developed to meet the requirement of stability. Phase fluctuations of the laser are measured by the interferometer with a photodetector and then digitalized to raw random numbers with a rate of 80 Gbps. The min-entropy of the raw data is evaluated by modeling the system and is used to quantify the quantum randomness of the raw data. The bias of the raw data caused by other signals, such as classical and detection noises, can be removed by Toeplitz-matrix hashing randomness extraction. The final random numbers can pass through the standard randomness tests. Our demonstration shows that high-speed quantum random number generators are ready for practical usage.

  5. Manipulating atoms in an optical lattice: Fractional fermion number and its optical quantum measurement

    NASA Astrophysics Data System (ADS)

    Ruostekoski, J.; Javanainen, J.; Dunne, G. V.

    2008-01-01

    We provide a detailed analysis of our previously proposed scheme [J. Ruostekoski, G. V. Dunne, and J. Javanainen, Phys. Rev. Lett. 88, 180401 (2002)] to engineer the profile of the hopping amplitudes for atomic gases in a one-dimensional optical lattice so that the particle number becomes fractional. We consider a constructed system of a dilute two-species gas of fermionic atoms where the two components are coupled via a coherent electromagnetic field with a topologically nontrivial phase profile. We show both analytically and numerically how the resulting atomic Hamiltonian in a prepared dimerized optical lattice with a defect in the pattern of alternating hopping amplitudes exhibits a fractional fermion number. In particular, in the low-energy limit we demonstrate the equivalence of the atomic Hamiltonian to a relativistic Dirac Hamiltonian describing fractionalization in quantum field theory. Expanding on our earlier argument [J. Javanainen and J. Ruostekoski, Phys. Rev. Lett. 91, 150404 (2003)] we show how the fractional eigenvalues of the particle number operator can be detected via light scattering. In particular, we show how scattering of far-off resonant light can convey information about the counting and spin statistics of the atoms in an optical lattice, including state-selective atom density profiles and atom number fluctuations. Optical detection could provide a truly quantum mechanical measurement of the particle number fractionalization in a dilute atomic gas.

  6. Measuring aerosol distribution and transport in London using a high density solar radiation measurement network

    NASA Astrophysics Data System (ADS)

    McConnell, Claire; Toumi, Ralf; Chazette, Patrick; Raut, Jean-Christophe; Haywood, James; Coe, Hugh; Morgan, William; McMeeking, Gavin; Williams, Paul; Turnbull, Kate

    2010-05-01

    Urban aerosols are important to human health and also cause a local direct radiative effect at the surface and the TOA. Regions surrounding urban areas are also sensitive to these effects through the aerosol transportation within the planetary boundary layer. We present a novel technique for studying the distribution of aerosols within and out of London. The technique uses a new high density network of continuous solar radiation measurements across London which form part of the OPAL (Open Air Laboratories) weather station network. We perform Langley extrapolations on the measured irradiance to infer the columnar amount of aerosol, and hence aerosol optical depth. This allows a map of aerosol optical depth across greater London to be produced. We evaluate results from this method by comparing results to measurements from the EM25 field campaign which took place during June 2009. During EM25 measurements of aerosols were made firstly by the UK FAAM (Facility for Airborne Atmospheric Measurements) BAe-146 aircraft, performing in-situ measurements, and secondly by a truck that was driven around London and equipped with a 355nm wavelength backscatter lidar, showing the vertical distribution of aerosol. The solar radiation measurements are also compared to data from London's PM2.5 and PM10 ground-based network, and to satellite aerosol optical depth data from MODIS at 550nm. The solar radiation network results show aerosol being transported to the southwest of London under the effect of a north-easterly prevailing wind. This shows good agreement with data from MODIS, PM2.5 and the EM25 field campaign measurements. This novel technique of using a high density network of solar radiation measurements is therefore able to monitor the distribution of aerosol across and out of London, and is presented as a useful way to infer aerosol distribution across urban areas.

  7. Unsteady force measurements in sphere flow from subcritical to supercritical Reynolds numbers

    NASA Astrophysics Data System (ADS)

    Norman, A. K.; McKeon, B. J.

    2011-11-01

    The flow over a smooth sphere is examined in the Reynolds number range of 5.0 × 104 < Re < 5.0 × 105 via measurements of the fluctuating forces and particle image velocimetry measurements in a planar cut of the velocity field. Comprehensive studies of the statistics and spectra of the forces are presented for a range of subcritical and supercritical Reynolds numbers. While the subcritical lateral force spectra are dominated by activity corresponding to the large-scale vortex shedding frequency at a Strouhal number of approximately 0.18, there is no such peak apparent in the supercritical spectra, although resolution effects may become important in this region. Nor does the large-scale vortex shedding appear to have a significant effect on the drag force fluctuations at either sub- or super-critical Reynolds numbers. A simple double spring model is shown to capture the main features of the lateral force spectra. The low-frequency force fluctuations observed in earlier computational studies are shown to have important implications for statistical convergence, and in particular, the apparent mean side force observed in earlier studies. At least one thousand dimensionless time units are required for reasonable estimates of the second and higher moments below the critical Reynolds number and even more for supercritical flow, stringent conditions for computational studies. Lastly, investigation of the relationship between the motion of the instantaneous wake shape, defined via the local position where the streamwise velocity is equal to half the freestream value, and the in-plane lateral force for subcritical flow reveals a significant negative correlation throughout the near wake, which is shown to be related to a structure inferred to arise from the large-scale vortex shedding convecting downstream at 61% of the freestream velocity. In addition to its utility in understanding basic sphere flow, the apparatus is also a testbed that will be used in future studies, examining the effect of both static and dynamic changes to the surface morphology.

  8. Accurate measurement of nanoparticle charge, number and size with the ELPI+™ instrument

    NASA Astrophysics Data System (ADS)

    Lamminen, Erkki

    2011-07-01

    Nanoparticle characterization is mainly carried out by microscopy techniques and measurements of size and concentration. However to be able to comprehensively understand the behavior of the aerosol, information on particle charge level is critical. Particle charge has a major effect on the coagulation, deposition and transport as well as on the health effects of the particles. While aged aerosols generally are mainly neutral in terms of charge, freshly generated or resuspended particles can have high charge levels that vary depending on the size, material and generation method of the particles. Charging processes for particles are problematic as they are usually both time dependent and material dependent with sudden changes in magnitude. This makes the charge of a particle nearly impossible to predict without detailed studies and direct measurements. ELPI+™ instrument is a completely new aerosol measurement instrument based on the widely used Electrical Low Pressure Impactor (ELPI) technique. ELPI+™ measures particle concentration and size in a wide size range from 6nm to 10μm in real-time. The operation is based on first charging the particles in a corona charger and then size segregating them in a cascade impactor where all impactor stages are electrically insulated. With the ELPI+™ instrument it is possible to measure not only the particle size and concentration in real-time, but also the charge distribution of the particles. As the particle size classification is made with an impactor, the measured particles can be subsequently analyzed if needed with a suitable technique.

  9. A transportable hemispherical illumination system for making reflectance factor measurements

    NASA Technical Reports Server (NTRS)

    Williams, Darrel L.; Wood, Frank M., Jr.

    1987-01-01

    An artificial source of stable, hemispherical illumination has been developed to facilitate the collection of reflectance factor measurements of targets of interest in a laboratory environment. The light source consists of a 76 cm (30 in.) aluminum hemisphere which has been coated internally with barium sulfate paint. Illumination is provided by two banks of lamps, each consisting of eight 62-W quartz halogen bulbs which have tungsten filaments. An internal baffle precludes the viewing of any direct beam of light. A simple metal structure has been developed to hold the hemisphere and all peripheral equipment, such as spectrometers, radiometers, and cameras, in place during data collection. The entire setup can be easily disassembled and packed in airline approved shipping cases to facilitate transportation to remote laboratory facilities. This illumination system has been used during the past three years to collect spectral reflectance factor data of tree branch samples and seedlings in support of an on-going study to investigate the effect of acidic deposition on forest vegetation.

  10. Ozone Measurements and a 3D Chemical Transport Model

    NASA Technical Reports Server (NTRS)

    Stolarski, Richard S.; Douglass, Anne R.; Frith, Stacey; Steenrod, Steven; Polansky, Brian

    2004-01-01

    We have used our three-dimensional chemical transport model (CTM) to calculate the expected reponse of stratospheric composition over the past 30 years to forcing by chlorine and bromine compounds, solar ultraviolet, and volcanic aerosols. The CTM uses off-line winds and temperatures fiom a 50-year run of the finite volume general circulation model (FVGCM). We compare the total column ozone and the ozone profile fiom the CTM output to a variety of data sources. These include a merged total ozone data set from TOMS and SBUV using the new version 8 algorithm. Total ozone fiom the CTM are compared to ground-station measurements of total ozone at specific locations. Ozone profiles are compared to satellite meausrements fiom SBUV, SAGE, and HALOE. Profiles are also compared to ozonesondes over several locations. The results of the comparisons are quantified by using a time-series statistical analysis to determine trends, solar cycle, and volcanic reponse in both the model and in the data. Initial results indicate that the model responds to forcings in a way that is similar to the observed atmospheric response. The model does seem to be more sensitive to the chlorine and bromine perturbation ihan is the data. Further details and comparisons wiii be discussed.

  11. Heterodyne and adaptive phase measurements on states of fixed mean photon number

    NASA Astrophysics Data System (ADS)

    Berry, D.; Wiseman, H. M.; Zhang, Zhong-Xi

    1999-09-01

    The standard technique for measuring the phase of a single-mode field is heterodyne detection. Such a measurement may have an uncertainty far above the intrinsic quantum phase uncertainty of the state. Recently it has been shown [H. M. Wiseman and R. B. Killip, Phys. Rev. A 57, 2169 (1998)] that an adaptive technique introduces far less excess noise. Here we quantify this difference by an exact numerical calculation of the minimum measured phase variance for the various schemes, optimized over states with a fixed mean photon number. We also analytically derive the asymptotics for these variances. For the case of heterodyne detection our results disagree with the power law claimed by D'Ariano and Paris [Phys. Rev. A 49, 3022 (1994)].

  12. The number needed to treat: a clinically useful measure of treatment effect.

    PubMed Central

    Cook, R. J.; Sackett, D. L.

    1995-01-01

    The relative benefit of an active treatment over a control is usually expressed as the relative risk, the relative risk reduction, or the odds ratio. These measures are used extensively in both clinical and epidemiological investigations. For clinical decision making, however, it is more meaningful to use the measure "number needed to treat." This measure is calculated on the inverse of the absolute risk reduction. It has the advantage that it conveys both statistical and clinical significance to the doctor. Furthermore, it can be used to extrapolate published findings to a patient at an arbitrary specified baseline risk when the relative risk reduction associated with treatment is constant for all levels of risk. PMID:7873954

  13. Particle concentrations and number size distributions in the planetary boundary layer derived from airship based measurements

    NASA Astrophysics Data System (ADS)

    Tillmann, Ralf; Zhao, Defeng; Ehn, Mikael; Hofzumahaus, Andreas; Holland, Frank; Rohrer, Franz; Kiendler-Scharr, Astrid; Wahner, Andreas

    2014-05-01

    Atmospheric particles play a key role for regional and global climate due to their direct and indirect radiative forcing effects. The concentration and size of the particles are important variables to these effects. Within the continental planetary boundary layer (PBL) the particle number size distribution is influenced by meteorological parameters, local sinks and sources resulting in variable spatial distributions. However, measurements of particle number size distributions over a broad vertical range of the PBL are rare. The airship ZEPPELIN NT is an ideal platform to measure atmospheric aerosols on a regional scale within an altitude range up to 1000 m. For campaigns in the Netherlands, Northern Italy and South Finland in 2012 and 2013 the airship was deployed with a wide range of instruments, including measurements of different trace gases, short lived radicals, solar radiation, aerosols and meteorological parameters. Flights were carried out at different times of the day to investigate the influence of the diurnal evolution of the PBL on atmospheric trace gases and aerosols. During night and early morning hours the concentration and size distribution of atmospheric particles were found to be strongly influenced by the layered structure of the PBL, i.e. the nocturnal boundary layer and the residual layer. Within the residual layer particle concentrations stay relatively constant as this layer is decoupled from ground sources. The particles persist in the accumulation mode as expected for an aged aerosol. In the nocturnal boundary layer particle concentrations and size are more dynamic with higher concentrations than in the residual layer. A few hours after sunrise, the layered structure of the PBL intermixes. During daytime the PBL is well mixed and a negative concentration gradient with increasing height is observed. Several height profiles at different times of the day and at different locations in Europe were measured. The aerosol measurements will be discussed together with meteorological parameters and trace gas measurements. Acknowledgement: PEGASOS project funded by the European Commission and the Framework Program 7 (FP7-ENV-2010-265148).

  14. Mobile lidar system for measurement of water vapor mixing ratio and ozone number density

    NASA Technical Reports Server (NTRS)

    Whiteman, D.

    1988-01-01

    The Water Vapor Lidar was modified and extended to make differential absorption measurements of ozone. Water vapor measurements make use of a weak molecular scattering process known as Raman scattering. It is characterized by a shift in wavelength of the scattered beam of light relative to the incident one. Some of the energy of the incident photon is converted to vibrational or rotational energy within the molecule leaving the scattered photon shifted to a slightly longer wavelength. When performing water vapor measurements, profiles are acquired of water vapor mixing ratio from near the ground to beyond 7 km every 2 minutes. By forming a color composite image of the individual profiles, the spatial and temporal evolution of water vapor is visible with vertical resolution of 75 to 150m and temporal resolution of 2 minutes. The ozone lidar is intended for use as a cross calibration facility for other stationary ozone lidar systems. The ozone measurement employs the technique known as differential absorption. The backscattered laser radiation from two different wavelengths is measured. Successful measurements of 308 nm returns were made from 80 km with an averaging period of 6 hours. Using these data and a standard atmosphere density curve, an ozone number density profile was made which agrees very well with the standard ozone curve between 20 and 40 km.

  15. Mach number effects on velocity and density measurements in Richtmyer-Meshkov mixing

    NASA Astrophysics Data System (ADS)

    Wilson, Brandon; Mejia-Alvarez, Ricardo; Prestridge, Kathy; Ding, Liuyang

    2014-11-01

    Richtmyer-Meshkov (RM) mixing is sensitive to many parameters: incident Mach number, Atwood number, and initial interface perturbations. The correlation between turbulence and mixing quantities and these parameters is not well-understood. The Vertical Shock Tube (VST) at Los Alamos National Lab is designed to measure the spectrum of scales existing in RM mixing growth and transition to turbulence. We use density (PLIF) and velocity (PIV) diagnostics to understand the effects of Mach number on an air-SF6 interface with multimode perturbations. We quantify Ma effects on the evolution of RM growth at large scales. We then statistically characterize the effect of shock strength on small scale turbulence and mixing (e . g . Favre-averaged Reynolds stresses, instantaneous dissipation rate, and vorticity) at specific times after first shock. First shock mixing appears to transition to turbulence, and we examine the conditions of this transition. We also use first measurements of tomographic PIV in the vertical shock tube to investigate RM mixing anisotropy.

  16. Markstein Numbers of Negatively-Stretched Premixed Flames: Microgravity Measurements and Computations

    NASA Technical Reports Server (NTRS)

    Ibarreta, Alfonso F.; Driscoll, James F.; Feikema, Douglas A.; Salzman, Jack (Technical Monitor)

    2001-01-01

    The effect of flame stretch, composed of strain and curvature, plays a major role in the propagation of turbulent premixed flames. Although all forms of stretch (positive and negative) are present in turbulent conditions, little research has been focused on the stretch due to curvature. The present study quantifies the Markstein number (which characterizes the sensitivity of the flame propagation speed to the imposed stretch rate) for an inwardly-propagating flame (IPF). This flame is of interest because it is negatively stretched, and is subjected to curvature effects alone, without the competing effects of strain. In an extension of our previous work, microgravity experiments were run using a vortex-flame interaction to create a pocket of reactants surrounded by an IPF. Computations using the RUN-1DL code of Rogg were also performed in order to explain the measurements. It was found that the Markstein number of an inwardly-propagating flame, for both the microgravity experiment and the computations, is significantly larger than that of an outwardly-propagating flame. Further insight was gained by running the computations for the simplified (hypothetical) cases of one step chemistry, unity Lewis number, and negligible heat release. Results provide additional evidence that the Markstein numbers associated with strain and curvature have different values.

  17. The measurement of a complete set of transport properties for a concentrated solid polymer electrolyte solution

    SciTech Connect

    Ma, Y.; Doyle, M.; Doeff, M.M.; De Jonghe, L.C.; Newman, J.; Fuller, T.F.

    1995-06-01

    Polymer electrolytes based on alkali metal salts in poly(ethylene oxides) are important for possible use in rechargeable batteries for both electric vehicle and consumer electronics applications. The authors measure a complete set of transport properties for one particular binary salt solution: sodium trifluoromethanesulfonate in poly(ethylene oxide), over a wide range of salt concentrations (0.1 to 2.6M) at 85 C. The properties measured include the conductivity, the salt diffusion coefficient, and the Na ion transference number. The mean molar activity coefficient of the salt is also determined. The conductivity and diffusion coefficients of NaCF{sub 3}SO{sub 3} are similar in magnitude to those of LiCF{sub 3}SO{sub 3} in (polyethylene oxide). The transference number and thermodynamic factor are found by combining concentration cell data with the results of galvanostatic polarization experiments. A theoretical analysis of the experimental method based on concentrated-solution theory is given. The study verifies that the transference numbers derived from the experiments retain fundamental significance in applications involving both steady and transient processes and in systems coupling the polymer electrolyte with electrodes of all types (stoichiometries). The relevant transference numbers can be determined independently of any knowledge of speciation of the polymer electrolyte. The transference numbers found here for the sodium ion are much lower than those reported for the lithium ion, especially in the concentrated solutions. The transference number of the sodium ion is negative in the more concentrated solutions and levels off at its maximum value of 0.31 in the dilute concentration range. The transference number results are interpreted in terms of complexation of the sodium ion with the anionic species.

  18. High spatial range velocity measurements in a high Reynolds number turbulent boundary layer

    NASA Astrophysics Data System (ADS)

    de Silva, C. M.; Gnanamanickam, E. P.; Atkinson, C.; Buchmann, N. A.; Hutchins, N.; Soria, J.; Marusic, I.

    2014-02-01

    Here, we detail and analyse a multi-resolution particle image velocity measurement that resolves the wide range of scales prevalent in a zero pressure gradient turbulent boundary layer at high Reynolds numbers (up to Reτ ≈ 20 000). A unique configuration is utilised, where an array of eight high resolution cameras at two magnification levels are used simultaneously to obtain a large field of view, while still resolving the smaller scales prevalent in the flow. Additionally, a highly magnified field of view targeted at the near wall region is employed to capture the viscous sublayer and logarithmic region, with a spatial resolution of a few viscous length scales. Flow statistics from these measurements show good agreement with prior, well resolved hot-wire anemometry measurements. Analysis shows that the instantaneous wall shear stress can be reliably computed, which is historically known to be challenging in boundary layers. A statistical assessment of the wall shear stress shows good agreement with existing correlations, prior experimental and direct numerical simulation data, extending this view to much higher Reynolds numbers. Furthermore, conditional analysis using multiple magnification levels is detailed, to study near-wall events associated with high skin friction fluctuations and their associated overlaying structures in the log region. Results definitively show that the passage of very large-scale positive (or negative) velocity fluctuations are associated with increased (or reduced) small-scale variance in wall shear stress fluctuations.

  19. Statistical characterization of multi-conductor cables using large numbers of measurements.

    SciTech Connect

    Higgins, Matthew B.

    2005-01-01

    Understanding and characterizing the electrical properties of multi-conductor shielded and unshielded cables is an important endeavor for many diverse applications, including airlines, land based communications, nuclear weapons, and any piece of hardware containing multi-conductor cabling. Determining the per unit length capacitance and inductance based on the geometry of the conductors, number of conductors, and characteristics of the shield can prove quite difficult. Relating the inductance and capacitance to shielding effectiveness can be even more difficult. An exceedingly large number of measurements were taken to characterize eight multi-conductor cables, of which four were 3-conductor cables and four were 18-conductor cables. Each set of four cables contained a shielded cable and an unshielded cable with the inner conductors twisted together and a shielded cable and an unshielded cable with the inner conductors not twisted together (or straight). Male LJT connectors were attached on either end of the cable and each cable had a finished length of 22.5 inches. The measurements performed were self and mutual inductance, self and mutual capacitance, and effective height. For the 18 conductor case there ended up being an 18 by 18 element matrix for inductance (with the self inductance terms lying on the diagonal) and an 18 by 18 matrix for capacitance. The effective height of each cable was measured over a frequency range from 220 MHz to 18 GHz in a Mode-Stirred Chamber. The effective height of each conductor of each cable was measured individually and all shorted together, producing 19 frequency responses for each 18 conductor cable. Shielding effectiveness was calculated using the effective heights from the shielded and unshielded cables. The results of these measurements and the statistical analysis of the data will be presented. There will also be a brief presentation of comparison with numerical models.

  20. Impact of prospective payments on a tertiary care center receiving large numbers of critically ill patients by aeromedical transport.

    PubMed

    Thomas, F; Larsen, K; Clemmer, T P; Burke, J P; Orme, J F; Napoli, M; Christison, E

    1986-03-01

    To determine the economic impact of federal prospective payments and the potential effect if private insurance payers were to implement similar prospective payments, we examined payments under Medicare diagnosis-related grouping (DRG) reimbursement policies for 105 Medicare and 357 non-Medicare patients admitted to a tertiary care center via air transport. Among the 105 Medicare patients, the average length of stay was 11.4 days and the mortality rate was 24%. Hospital charges exceeded DRG reimbursement for 74% of Medicare patients. A comparison of previous Medicare payment policies to current federal DRG reimbursement resulted in a revenue loss to the hospital of $667,229 ($6335 per patient). For the 357 non-Medicare patients, the average length of stay was 10.8 days, the mortality rate was 10%, and hospital charges exceeded Medicare DRG reimbursement for 78% of the patients. Implementation of DRG-like payments by non-Medicare insurers would create a hospital revenue loss of $2,493,048 ($6983 per patient). We conclude that unless current and planned prospective payment policies are modified, the use of aeromedical transport services to recruit large numbers of critically ill patients to tertiary care centers is economically prohibitive. PMID:3080276

  1. Particle number emissions of motor traffic derived from street canyon measurements in a Central European city

    NASA Astrophysics Data System (ADS)

    Klose, S.; Birmili, W.; Voigtländer, J.; Tuch, T.; Wehner, B.; Wiedensohler, A.; Ketzel, M.

    2009-02-01

    A biennial dataset of ambient particle number size distributions (diameter range 4-800 nm) collected in urban air in Leipzig, Germany, was analysed with respect to the influence of traffic emissions. Size distributions were sampled continuously in 2005 and 2006 inside a street canyon trafficked by ca. 10 000 motor vehicles per day, and at a background reference site distant at 1.5 km. Auto-correlation analysis showed that the impact of fresh traffic emissions could be seen most intensely below particle sizes of 60 nm. The traffic-induced concentration increment at roadside was estimated by subtracting the urban background values from the street canyon measurement. To describe the variable dispersion conditions inside the street canyon, micro-meteorological dilution factors were calculated using the Operational Street Pollution Model (OSPM), driven by above-roof wind speed and wind direction observations. The roadside increment concentrations, dilution factor, and real-time traffic counts were used to calculate vehicle emission factors (aerosol source rates) that are representative of the prevailing driving conditions, i.e. stop-and-go traffic including episodes of fluent traffic flow at speeds up to 40 km h-1. The size spectrum of traffic-derived particles was essentially bimodal - with mode diameters around 12 and 100 nm, while statistical analysis suggested that the emitted number concentration varied with time of day, wind direction, particle size and fleet properties. Significantly, the particle number emissions depended on ambient temperature, ranging between 4.8 (±1.8) and 7.8 (±2.9).1014 p. veh-1 km-1 in summer and winter, respectively. A separation of vehicle types according to vehicle length suggested that lorry-like vehicles emit about 80 times more particle number than passenger car-like vehicles. Using nitrogen oxide (NOx) measurements, specific total particle number emissions of 338 p. (pg NOx)-1 were inferred. The calculated traffic emission factors, considering particle number and size, are anticipated to provide useful input for future air quality and particle exposure modelling in densely populated urban areas.

  2. Improvement of Pulping Uniformity by Measurement of Single Fiber Kappa Number

    SciTech Connect

    Richard R. Gustafson; James B. Callis

    2001-11-20

    A method to measure the kappa of single fibers by staining with a fluorescent dye, Acridine Orange (AO), has been developed. This method is now applied to develop and automated flow-through instrument that permits routine kappa analysis on thousands of images of AO stained fibers to give the fiber kappa number distribution of a pulp sample in a few minutes. The design and operation of the instrument are similar to that of a flow cytometer but with the addition of extensive fiber imaging capability. Fluorescence measurements in the flow-through instrument are found to be consistent with those made with fluorescence microscope provided the signal processing in the flow-thou instrument is handled propertly. The kappa distributions of pulps that were analyzed by means of a density gradient column are compared to those measured with the flow-through instrument with good results. The kappa distributions of various laboratory pulps and commercial pulps have been measured. It has been found that all pulps are non-uniform but that ommercial pulps generally have broader kappa distributions thatn their laboratory counterparts. The effects of different pulping methods and chip pretreatments on pulp uniformity are discussed in the report. Finally, the application of flow-through fluorescence technology to other single fiber measurements are presented.

  3. Probe Corrections for Mean Flow Measurements in High Reynolds Number Flows

    NASA Astrophysics Data System (ADS)

    Jiang, W.-M.; Li, J.-D.; McKeon, B. J.; Morrison, J. F.; Smits, A. J.

    2000-11-01

    We present a review of correction procedures for data taken in high Reynolds number turbulent flow using Pitot probes. Corrections must be made to account for the displacement of the effective center of the probe due to the effect of mean shear, turbulent intensity, viscous effects, the finite size of pressure tappings, compressibility and probe-strut interference. The effects of various correction methods and the resulting uncertainty in the mean flow measurements are assessed using new Pitot probe and hot wire data taken in the Princeton/ONR Superpipe facility (http://www.princeton.edu/ gasdyn/), together with the earlier Pitot probe data of Zagarola.

  4. The Experimental Measurement of Aerodynamic Heating About Complex Shapes at Supersonic Mach Numbers

    NASA Technical Reports Server (NTRS)

    Neumann, Richard D.; Freeman, Delma C.

    2011-01-01

    In 2008 a wind tunnel test program was implemented to update the experimental data available for predicting protuberance heating at supersonic Mach numbers. For this test the Langley Unitary Wind Tunnel was also used. The significant differences for this current test were the advances in the state-of-the-art in model design, fabrication techniques, instrumentation and data acquisition capabilities. This current paper provides a focused discussion of the results of an in depth analysis of unique measurements of recovery temperature obtained during the test.

  5. Cryptographic random number generators for low-power distributed measurement system

    NASA Astrophysics Data System (ADS)

    Czernik, Pawel; Olszyna, Jakub

    2009-06-01

    In this paper we present the State of The Art in Cryptographic Random Number Generators (RNG). We provide analysis of every of the most popular types of RNGs such as linear generators (i.e. congruential, multiple recursive), non-linear generators (i.e. Quadratic, Blum-Blum-Shub) and cryptographic algorithms based (i.e. RSA generator, SHA-1 generator). Finally we choose solutions which are suitable to Distributed Measurement Systems (DMS) specific requirements according to cryptographic security, computational efficiency (throughput) and complexity of implementation (VHDL targeted at FPGA and ASIC devices). Strong asymmetry of computing power and memory capacity is taken into account in both software and hardware solutions.

  6. Transport measurements in intercalated graphite and fullerene compounds

    SciTech Connect

    Vittorio, S.L. di.

    1992-01-01

    THe author has investigated the transport properties of fluorine-intercalated vapor-grown graphite fibers with concentrations spanning the range C[sub 2.9]F to C[sub 6.6]F, corresponding to stage I and stage II samples. The samples were characterized by X-ray diffraction, weight uptake measurements and X-ray Photo-electron Spectroscopy (XPS). Among all Graphite Intercalation Compounds (GIC), fluorine is unique in that intercalation introduces a large disorder into the very ordered pristine graphene planes. Intercalation with an acceptor compound increases the anisotropy of the conductivity. Therefore, dilute samples exhibit weak localization and carrier-carrier interaction effects typical of a two-dimensional disordered metal. As the fluorine concentration increases, the bonding between fluorine and carbons shifts from ionic to covalent, which reduces the carrier concentration, resulting in a metal-insulator transition and strong localization. Magnetotransport at low temperatures (0.5K-30K) has been used to investigate the effect of disorder on the electronic properties of both metallic and semiconducting two-dimensional solids. The disorder present in the fluorine GICs was characterized by Transmission Electron Microscopy (TEM) as well as Electronic Spin Resonance (ESR). The distribution of fluorine throughout the graphene layers is inhomogeneous, with the formation of both dilute and concentrated islands. The bonding between carbon and fluorine is predominantly ionic within the dilute islands, whereas the concentrated islands contain mostly localized electrons. Another feature is the waviness of the graphene planes, which increases with increasing fluorine concentration. The disorder is explained by a model of nucleation of a covalent fluorine phase within the ionic matrix at high fluorine concentration. The last chapter describes the intercalation of C[sub 60] with Rubidium, and an Electron Spin Resonance study of the various Rb[sub x]C[sub 60] samples prepared.

  7. Evaluation of uncertainties in femtoampere current measurement for the number concentration standard of aerosol nanoparticles

    NASA Astrophysics Data System (ADS)

    Sakurai, Hiromu; Ehara, Kensei

    2011-02-01

    We evaluated uncertainties in current measurement by the electrometer at the current level on the order of femtoamperes. The electrometer was the one used in the Faraday-cup aerosol electrometer of the Japanese national standard for number concentration of aerosol nanoparticles in which the accuracy of the absolute current is not required, but the net current which is obtained as the difference in currents under two different conditions must be measured accurately. The evaluation was done experimentally at the current level of 20 fA, which was much smaller than the intervals between the electrometer's calibration points at +1, +0.5, -0.5 and -1 pA. The slope of the response curve for the relationship between the 'true' and measured current, which is crucial in the above measurement, was evaluated locally at many different points within the ±1 pA range for deviation from the slope determined by a linear regression of the calibration data. The sum of the current induced by a flow of charged particles and a bias current from a current-source instrument was measured by the electrometer while the particle current was toggled on and off. The net particle current was obtained as the difference in the measured currents between the toggling, while at the same time the current was estimated from the particle concentration read by a condensation particle counter. The local slope was calculated as the ratio of the measured to estimated currents at each bias current setting. The standard deviation of the local slope values observed at varied bias currents was about 0.003, which was calculated by analysis of variance (ANOVA) for the treatment of the bias current. The combined standard uncertainty of the slope, which was calculated from the uncertainty of the slope by linear regression and the variability of the slope, was calculated to be about 0.004.

  8. Measuring the modulation transfer function of image capture devices: what do the numbers really mean?

    NASA Astrophysics Data System (ADS)

    Zhang, Xujie; Kashti, Tamar; Kella, Dror; Frank, Tal; Shaked, Doron; Ulichney, Robert; Fischer, Mani; Allebach, Jan P.

    2012-01-01

    The modulation transfer function (MTF) is a fundamental tool for assessing the performance of imaging systems. It has been applied to a range of capture and output devices, including printers and even the media itself. In this paper, we consider the problem of measuring the MTF of image capture devices. We analyze the factors that limit the MTF of a capture device. Then, we examine three different approaches to this task based, respectively, on a slant-edge target, a sinewave target, and a grill pattern. We review the mathematical relationship between the three different methods, and discuss their comparative advantages and disadvantages. Finally, we present experimental results for MTF measurement with a number of different commercially available image capture devices that are specifically designed for capture of 2D reflection or transmission copy. These include camera-based systems, flat-bed scanners, and a drum scanner.

  9. A technique for sensors fusion with limited number of common measures

    NASA Astrophysics Data System (ADS)

    Quaranta, Carlo; Balzarotti, Giorgio

    2015-06-01

    An algorithm is proposed here that overcomes the problem of the not exhaustive number of common measures from sensors of different kind. In the presence of a suite of heterogeneous sensors, the data fusion process has to deal with the problem of managing different information, generally not directly comparable. The analysis of the mathematical model is carried out considering a data fusion system between radar and Infrared Search and Track (IRST) where the measurement of the range is achieved by radar only. Simulation results demonstrate the effectiveness of the algorithm as regards the fusion process, tracking and correctness of association among tracks from different sensors. A comparison with a known approach from the literature about the fusion equation is also performed.

  10. Particle Image Velocimetry Measurements of Turbulent Jets at Different Mach Numbers

    NASA Astrophysics Data System (ADS)

    Wang, Zhexuan; Andreopoulos, Yiannis

    2001-11-01

    Compressibility and density effects in subsonic turbulent jets have been investigated experimentally. Helium, Nitrogen and Krypton gases were used in the jet flow issuing into still air at Mach number 0.3, 0.6 and 0.9 respectively. PIV (Particle Image Velocimetry) based on Cross-Correlation and Auto-Correlation methods was carried out, with double-pulse laser being the light source for visualization and quantitative measurements, and talcum powders being the seeding particles. The velocity distribution obtained indicated that the decay of Helium is the fastest, while the decay of Krypton is the slowest. Correspondingly, the level of turbulence fluctuation is also higher in case of Helium Jets indicating better mixing with the ambient air. The results cooperate very well with previous pressure measurements. Sponsored by NASA Grant #NAG-1590

  11. Measuring and controlling the transport of magnetic nanoparticles

    NASA Astrophysics Data System (ADS)

    Stephens, Jason R.

    Despite the large body of literature describing the synthesis of magnetic nanoparticles, few analytical tools are commonly used for their purification and analysis. Due to their unique physical and chemical properties, magnetic nanoparticles are appealing candidates for biomedical applications and analytical separations. Yet in the absence of methods for assessing and assuring their purity, the ultimate use of magnetic particles and heterostructures is likely to be limited. For magnetic nanoparticles, it is the use of an applied magnetic flux or field gradient that enables separations. Flow based techniques are combined with applied magnetic fields to give methods such as magnetic field flow fractionation and high gradient magnetic separation. Additional techniques have been explored for manipulating particles in microfluidic channels and in mesoporous membranes. This thesis further describes development of these and new analytical tools for separation and analysis of colloidal particles is critically important to enable the practical use of these, particularly for medicinal purposes. Measurement of transport of nanometer scale particles through porous media is important to begin to understand the potential environmental impacts of nanomaterials. Using a diffusion cell with two compartments separated by either a porous alumina or polycarbonate membrane as a model system, diffusive flux through mesoporous materials is examined. Experiments are performed as a function of particle size, pore diameter, and solvent, and the particle fluxes are monitored by the change in absorbance of the solution in the receiving cell. Using the measured extinction coefficient and change in absorbance of the solution as a function of time, the fluxes of 3, 8, and 14 nm diameter CoFe2O4 particles are determined as they are translocated across pores with diameters 30, 50, 100, and 200 nm in hexane and aqueous solutions. In general, flux decreases with increasing particle size and increases with pore diameter. We find that fluxes are faster in aqueous solutions than in hexane, which is attributed to the hydrophilic nature of the porous membranes and differences in wettability. The impact of an applied magnetic flux gradient, which induces magnetization and motion, on permeation is also examined. Surface chemistry plays an important role in determining flux through porous media such as in the environment. Diffusive flux of nanoparticles through alkylsilane modified porous alumina is measured as a model for understanding transport in porous media of differing surface chemistries. Experiments are performed as a function of particle size, pore diameter, attached hydrocarbon chain length and chain terminus, and solvent. Particle fluxes are monitored by the change in absorbance of the solution in the receiving side of a diffusion cell. In general, flux increases when the membranes are modified with alkylsilanes compared to untreated membranes, which is attributed to the hydrophobic nature of the porous membranes and differences in wettability. We find that flux decreases, in both hexane and aqueous solutions, when the hydrocarbon chain lining the interior pore wall increases in length. The rate and selectivity of transport across these membranes is related to the partition coefficient (Kp) and the diffusion coefficient (D) of the permeating species. By conducting experiments as a function of initial particle concentration, we find that KpD increases with increasing particle size, is greater in alkylsilane--modified pores, and larger in hexane solution than water. The impact of the alkylsilane terminus (--CH3, --Br, --NH2, --COOH) on permeation in water is also examined. In water, the highest KpD is observed when the membranes are modified with carboxylic acid terminated silanes and lowest with amine terminated silanes as a result of electrostatic effects during translocation. Finally, the manipulation of magnetic nanoparticles for the controlled formation of linked nanoparticle assemblies between microfluidic channels by the application of an external magnet is discussed. Two orthogonal channels were prepared using standard PDMS techniques with pressure-driven flow used to deliver the Fe3O4 and Au nanoparticle reactants. Nanoparticle assembly formation is based upon locally confined surface modification of Fe3O4 nanoparticles interacting with Au nanoparticles bridging the two particles together. For the magnetic particles, transfer between flow streams is greatly increased by placing a permanent magnet above and below the channel intersections. Multiple configurations of Fe3O 4 and Au nanoparticle assemblies are observed as a function of flow rate and interaction time of the individual nanoparticle components. We observe the formation of higher order assemblies by increasing the concentration of Fe3O4 nanoparticles introduced to the microfluidic device. This technique demonstrates the ability to form nanoparticle linked assemblies and could be easily linked to other analytical techniques developed in our lab to further isolate and separate a particular product. (Abstract shortened by UMI.)

  12. Direct Measurements of the Outer Membrane Stage of Ferric Enterobactin Transport

    PubMed Central

    Newton, Salete M.; Trinh, Vy; Pi, Hualiang; Klebba, Phillip E.

    2010-01-01

    When Gram-negative bacteria acquire iron, the metal crosses both the outer membrane (OM) and the inner membrane, but existing radioisotopic uptake assays only measure its passage through the latter bilayer, as the accumulation of the radionuclide in the cytoplasm. We devised a methodology that exclusively observes OM transport and used it to study the uptake of ferric enterobactin (FeEnt) by Escherichia coli FepA. This technique, called postuptake binding, revealed previously unknown aspects of TonB-dependent transport reactions. The experiments showed, for the first time, that despite the discrepancy in cell envelope concentrations of FepA and TonB (∼35:1), all FepA proteins were active and equivalent in FeEnt uptake, with a maximum turnover number of ∼5/min. FepA-mediated transport of FeEnt progressed through three distinct phases with successively decreasing rates, and from its temperature dependence, the activation energy of the OM stage was 33–35 kcal/mol. The accumulation of FeEnt in the periplasm required the binding protein and inner membrane permease components of its overall transport system; postuptake binding assays on strains devoid of FepB, FepD, or FepG did not show uptake of FeEnt through the OM. However, fluorescence labeling data implied that FepA was active in the ΔfepB strain, suggesting that FeEnt entered the periplasm but then leaked out. Further experiments confirmed this futile cycle; cells without FepB transported FeEnt across the OM, but it immediately escaped through TolC. PMID:20335169

  13. Aircraft Measurements of Saharan dust properties and impact of atmospheric transport during Fennec

    NASA Astrophysics Data System (ADS)

    Ryder, Claire; Highwood, Ellie; Rosenberg, Phil; Trembath, Jamie; Brooke, Jennifer; Bart, Mark; Dean, Angela; Dorsey, James; Crosier, Jonny; McQuaid, Jim; Brindley, Helen; Banks, James; Marsham, John; Sodemann, Harald; Washington, Richard

    2013-04-01

    Measurements of Saharan dust from recent airborne campaigns have found variations in size distributions and optical properties across Saharan and sub-Saharan Africa. These variations have an impact on radiation and thus weather and climate, and are important to characterise and understand, in particular, to understand how they vary with time after dust uplift, transport, and height in the atmosphere. New in-situ aircraft measurements from the Fennec 2011 aircraft campaign over a remote part of the Sahara Desert and the Atlantic Ocean will be presented and compared to previous airborne measurements. Size distributions extending to 300 μm will be shown, representing measurements extending further into the coarse mode than previously published for Saharan dust. The dust sampled by the aircraft covered a wide variety of loadings, dust source regions (Mali, Mauritania and Algeria) and dust ages (from fresh uplift to several days old). A significant coarse mode was present in the size distribution measurements with effective diameter up to 23 μm, and the mean size distribution showed greater concentrations of coarse mode than previous aircraft measurements. Single scattering albedo (SSA) values at 550nm calculated from these size distributions revealed high absorption from 0.77 to 0.95, with a mean of 0.85. Directly measured SSA values were higher (0.91 to 0.99) but new instrumentation revealed that these direct measurements, behind Rosemount inlets, overestimate the SSA by 0.02 to 0.20 depending on the concentration of coarse particles present. This is caused by inlet inefficiencies and pipe losses. Previous measurements of SSA from aircraft measurements may also have been overestimates for this reason. This has a significant impact on atmospheric heating rates. The largest dust particles were encountered closest to the ground, and were most abundant in cases where dust was freshly uplifted. Number concentration, mass loading and extinction coefficient showed inverse relationships to dust age, and showed some sensitivity to the type of uplift for cases of fresh dust. Vertical profiles of dust are found to be significantly different for freshly uplifted dust, aged dust, and dust transported over the ocean. Consequently, changes in the optical properties during dust transport are observed.

  14. Measuring Flux Distributions for Diffusion in the Small-Numbers Limit

    PubMed Central

    Seitaridou, Effrosyni; Inamdar, Mandar M.; Phillips, Rob; Ghosh, Kingshuk; Dill, Ken

    2012-01-01

    For the classical diffusion of independent particles, Fick's law gives a well-known relationship between the average flux and the average concentration gradient. What has not yet been explored experimentally, however, is the dynamical distribution of diffusion rates in the limit of small particle numbers. Here, we measure the distribution of diffusional fluxes using a microfluidics device filled with a colloidal suspension of a small number of microspheres. Our experiments show that (1) the flux distribution is accurately described by a Gaussian function; (2) Fick's law, that the average flux is proportional to the particle gradient, holds even for particle gradients down to a single particle difference; (3) the variance in the flux is proportional to the sum of the particle numbers; and (4) there are backward flows, where particles flow up a concentration gradient, rather than down it. In addition, in recent years, two key theorems about nonequilibrium systems have been introduced: Evans' fluctuation theorem for the distribution of entropies and Jarzynski's work theorem. Here, we introduce a new fluctuation theorem, for the fluxes, and we find that it is confirmed quantitatively by our experiments. PMID:17295536

  15. Time-dependent measurements over membrane plates at low Reynolds number

    NASA Astrophysics Data System (ADS)

    Hubner, James; Scott, Kyle; Timpe, Amory; Ukeiley, Lawrence

    2010-11-01

    A segment of low Reynolds number aerodynamic research employs biomimetics for optimization of airfoil shapes to micro air vehicle (MAV) flight. Many of these efforts focus on thin, flexible membrane airfoils inspired by small birds, bats and insects. This design approach, mimicking low Reynolds number flyers (Re < 100,000), has led to improved aerodynamic performance, particularly the mitigation of flow disturbances through passive aerodynamic and geometric twisting. In many cases, membrane vibration exists, altering the characteristics of the separated shear layer over the wing, leading to both advantageous and disadvantageous effects. Identifying and quantifying the nature of the fluid-structure coupling and how this coupling can passively control the flow is the goal of a recently initiated research project by the authors. This talk will present the objectives of the project and initial findings of synchronized flow (hot-wire anemometry) and surface deflection (laser vibrometry) measurements over rigid plates and flexible membranes at incidence to the free stream flow. A range of flow Reynolds numbers are examined, from 10,000 to 50,000, in which vibration initiates and grow with increasing velocity.

  16. Quantification of particle number emission factors for motor vehicles from on-road measurements.

    PubMed

    Morawska, Lidia; Jamriska, Milan; Thomas, Stephen; Ferreira, Luis; Mengersen, Kerrie; Wraith, Darren; McGregor, Fraser

    2005-12-01

    The database on particle number emission factors has been very limited to date despite the increasing interest in the effects of human exposure to particles in the submicrometer range. There are also major questions on the comparability of emission factors derived through dynamometer versus on-road studies. Thus, the aims of this study were (1) to quantify vehicle number emission factors in the submicrometer (and also supermicrometer) range for stop-start and free-flowing traffic at about 100 km h(-1) driving conditions through extensive road measurements and (2) to compare the emission factors from the road measurements with those obtained previously from dynamometer studies conducted in Brisbane. For submicrometer particles the average emission factors for Tora Street were estimated at (1.89 +/- 3.40) x 10(13) particles km(-1) (mean +/- standard error; n = 386) for petrol and (7.17 +/- 2.80) x 10(14) particles km(-1) (diesel; n = 196) and for supermicrometer particles at 2.59 x 10(9) particles km(-1) and 1.53 x 10(12) particles km(-1), respectively. The average number emission factors for submicrometer particles estimated for Ipswich Road (stop-start traffic mode) were (2.18 +/- 0.57) x 10(13) particles km(-1) (petrol) and (2.04 +/- 0.24) x 10(14) particles km(-1) (diesel). One implication of the conclusion that emission factors of heavy duty diesel vehicles are over 1 order of magnitude higher than emission factors of petrol-fueled passenger cars is that future control and management strategies should in particular target heavy duty vehicles, as even a moderate decrease in emissions of these vehicles would have a significant impact on lowering atmospheric concentrations of particles. The finding that particle number emissions per vehicle-km are significantly larger for higher speed vehicle operation has an important implication on urban traffic planning and optimization of vehicle speed to lower their impact on airborne pollution. Additionally, statistical analysis showed that neither the measuring method (dynamometer or on-road), nor data origin (Brisbane or elsewhere in the world), is associated with a statistically significant difference between the average values of emission factors for diesel, petrol, and vehicle fleet mix. However, statistical analyses of the effect of fuel showed that the mean values of emission factors for petrol and diesel are different at a 5% significance level. PMID:16382934

  17. Five-years of atmospheric aerosol number size distribution measurements in Eastern Mediterranean

    NASA Astrophysics Data System (ADS)

    Kalivitis, Nikolaos; Kouvarakis, Giorgos; Bougiatioti, Aikaterini; Stavroulas, Iasonas; Wiedensohler, Alfred; Mihalopoulos, Nikolaos

    2014-05-01

    The first long term measurements of atmospheric particle size distributions from the Eastern Mediterranean region are reported. Atmospheric aerosol number size distributions have been measured at the environmental research station of University of Crete at Finokalia, Crete, Greece (35° 20' N, 25° 40' E, 250m a.s.l) on a continuous base since 2008. A custom built (TROPOS type) scanning mobility particle sizer (SMPS) is used covering size ranges from 8 to 900 nm. The system is humidity controlled so that relative humidity is kept below 40% most of the time. Throughout the measuring period the average number concentration of the particles in the studied size range was found to be 2354 ± 1332 cm-3 (median of 2098 cm-3). Maximum concentrations are observed during summer while minimum during winter, reflecting the effectiveness of the removal processes in the region. Clear annual circles are found for the number concentrations of nucleation, Aitken and accumulation mode particles. Nucleation mode is presenting different pattern from the other two modes, with the highest concentrations during winter (and March) and the lowest during summer. New particle formation events are more frequently observed during March and October. The number size distributions present different seasonal patterns. During summer, unimodal distributions centering on the lower end of the accumulation mode size range are dominant in our observations. The prevailing meteorology characterized by the Etesian winds (Meltemi) and the lack of precipitation along the trajectory results to the arrival of well mixed air masses at Finokalia, carrying aged aerosol mainly from central and Eastern Europe. Regarding the other seasons, the shape of the distributions is more variable and strongly dependent on the air mass history: When the air masses are of marine origin or precipitation has affected them, the size distributions are mainly bimodal (peaking both in Aitken and in Accumulation mode). These distributions are representative of the background marine conditions at Finokalia. Unimodal distributions can be observed as well during the rest of the seasons depending on whether aged anthropogenic aerosol reach Crete before being removed from the atmosphere or not. The nucleation mode is observed mainly when new particle formation occurs and rarely can it be attributed to combustion processes or other sources.

  18. Array measurements adapted to the number of available sensors: Theoretical and practical approach for ESAC method

    NASA Astrophysics Data System (ADS)

    Galiana-Merino, J. J.; Rosa-Cintas, S.; Rosa-Herranz, J.; Garrido, J.; Peláez, J. A.; Martino, S.; Delgado, J.

    2016-05-01

    Array measurements of ambient noise have become a useful technique to estimate the surface wave dispersion curves and subsequently the subsurface elastic parameters that characterize the studied soil. One of the logistical handicaps associated with this kind of measurements is the requirement of several stations recording at the same time, which limits their applicability in the case of research groups without enough infrastructure resources. In this paper, we describe the theoretical basis of the ESAC method and we deduce how the number of stations needed to implement any array layout can be reduced to only two stations. In this way, we propose a new methodology to implement an N stations array layout by using only M stations (M < N), which will be recording in different positions of the original prearranged N stations geometry at different times. We also provide some practical guidelines to implement the proposed approach and we show different examples where the obtained results confirm the theoretical foundations. Thus, the study carried out reflects that we can use a minimum of 2 stations to deploy any array layout originally designed for higher number of sensors.

  19. Effect of Deborah number and phase difference on peristaltic transport of a third-order fluid in an asymmetric channel

    NASA Astrophysics Data System (ADS)

    Haroun, Mohamed H.

    2007-12-01

    The effect of a third-order fluid on the peristaltic transport in an asymmetric channel is studied. The wavelength of the peristaltic waves is assumed to be large compared to the varying channel width, whereas the wave amplitudes need not be small compared to the varying channel width. The channel asymmetry is produced by choosing the peristaltic wave train on the walls to have different amplitudes and phase. The flow is investigated in a wave frame of reference moving with velocity of the wave. The effects of Deborah number, phase difference, varying channel width and wave amplitudes on the pumping characteristics, streamline pattern and trapping phenomena are investigated. It is observed that the trapping regions increase as the channel becomes more and more symmetric and the trapped bolus volume decreases for increasing Deborah number, phase difference and varying channel width whereas it increases for increasing flow rate and wave amplitudes. Furthermore, the obtained results could also have applications to a range of peristaltic flows for a variety of non-Newtonian fluids such as aqueous solutions of high-molecular weight polyethylene oxide and polyacrylamide.

  20. Measurements and modeling of deposited particle transport by foot traffic indoors.

    PubMed

    Sippola, Mark R; Sextro, Richard G; Thatcher, Tracy L

    2014-04-01

    Deposited particles are transported into and within buildings by adhering to and releasing from people's shoes. To better understand transport of deposited particulate contaminants and exposures to these materials, experimental data on tracking by foot traffic are needed. Laboratory experiments measured uptake and downlay mass transfer efficiencies of particles between shoes and floors in a step-simulation chamber. Equilibrium uptake transfer fractions, the net mass fraction transferred from floors to shoes after several steps, were also measured. Single-step uptake and downlay transfer efficiencies ranged from 0.02 to 0.22 and equilibrium uptake transfer fractions were 0.10-0.40. Particle size, particle loading, shoe type, floor type, step pressure, and step sequence were all investigated. Experiments demonstrated that single-step downlay transfer efficiencies decrease with each successive step onto clean floors. A simple empirical model is proposed to estimate these transfers as a function of step number. Simulations using the transfer efficiency values measured here illustrate the spread of deposited particles by people walking in a hypothetical hallway. These simulations show that in locations where a few people walk over the same area each minute, tracking can spread deposited material over length scales comparable to building dimensions in just a few hours. PMID:24579974

  1. Optimal Number of Angle Images for Calculating Anterior Angle Volume and Iris Volume Measurements

    PubMed Central

    Blieden, Lauren S.; Chuang, Alice Z.; Baker, Laura A.; Bell, Nicholas P.; Fuller, Timothy S.; Mankiewicz, Kimberly A.; Feldman, Robert M.

    2015-01-01

    Purpose. We determined the optimal number of angle images required to obtain reliable measurements of trabecular-iris circumferential volume (TICV) and iris volume (IV) using swept-source Fourier domain anterior segment optical coherence tomography (SSFD-ASOCT) scans in narrow angle eyes. Methods. Scleral spur landmarks (SSL) were manually identified on ASOCT angle images from 128 meridians from each of 24 eyes with chronic primary angle closure (PAC) spectrum of disease. The anterior and posterior corneal curves, and the anterior and posterior iris surfaces were identified automatically by the anterior chamber analysis and interpretation (ACAI) software, then manually examined and edited by the reader if required. Trabecular-iris circumferential volume at 750 μm from SSL (TICV750) and IV were subsequently calculated using varying numbers of angle images. Threshold error was determined to be less than the lower 95% confidence limit of mean absolute percent error (MAPE) of the change in TICV or IV resulting from laser peripheral iridotomy, which would be 17% for TICV and 5% for IV, based on previous studies. The optimal number of angle images was the smallest number of images where MAPE was less than this threshold for TICV and IV. Results. A total of 32 equally-spaced angle images (16 meridians) was required to estimate TICV750 and 16 angle images (8 meridians) to estimate IV. Both were within 4.6% and 1.6% of MAPE, respectively. Conclusions. It is possible to determine TICV and IV parameters reliably in narrow angles without evaluating all 128 meridians obtained with SSFD-ASOCT. PMID:25829412

  2. Inverse relationship between numbers of 5-HT transporter binding sites and life history of aggression and intermittent explosive disorder.

    PubMed

    Coccaro, Emil F; Lee, Royce; Kavoussi, Richard J

    2010-02-01

    The objective of this study was to determine if platelet 5-HT transporter (5-HTT) sites vary as a function of aggression, and/or impulsiveness, and differ as a function of Intermittent Explosive Disorder (IED). Accordingly, the number of platelet 5-HTT sites was assessed in 100 personality disordered (PD) individuals with varying degrees of aggressiveness. The number of platelet 5-HTT sites was assessed by examining the Bmax of H(3)-Paroxetine Binding to the blood platelet. Life history of aggression was assessed by Life History of Aggression. Impulsivity was assessed by the Barratt Impulsiveness Scale. Diagnoses of IED were made by both DSM-IV and Research Criteria. Examination of the data revealed that Bmax, but not Kd, values of Platelet H(3)-Paroxetine Binding correlated inversely with the LHA Aggression score (r=-.42 n=87, p<.001) but not with the BIS-11 Impulsivity score (r=.03, n=77, p=.777). PD subjects meeting Research Criteria for IED demonstrated a significant reduction in Bmax values for Platelet H(3)-Paroxetine Binding. These results were similar after accounting for the effect of lifetime history of depressive mood disorder on Bmax values for Platelet H(3)-Paroxetine Binding. These data indicate a significant inverse relationship between platelet 5-HTT and aggression, though not impulsivity, as a dimensional variable in personality disordered individuals. Results from the examination of IED as a categorical aggression variable suggest that Research, rather than DSM-IV, criteria better identify individuals with reduced numbers of platelet 5-HTT sites. PMID:19767013

  3. Measurements and analysis of electron transport coefficients obtained by a pulsed Townsend technique

    NASA Astrophysics Data System (ADS)

    Šašić, O.; de Urquijo, J.; Juárez, A. M.; Dupljanin, S.; Jovanović, J.; Hernández-Ávila, J. L.; Basurto, E.; Petrović, Z. Lj

    2010-06-01

    A review of a wide range of electron swarm studies in several pure gases and gas mixtures is given. These studies include the determination of the cross section set for electrons in C2H2F2 (R134a) based on recent measurements of transport data, the re-analysis of the cross sections for electrons in N2O and its mixtures with N2 and SF6 and, finally, the analysis of electron transport in N2-Ar and Xe-He mixtures. It was found that in the case of R134a further studies of the characteristic energy are needed for its mixtures with argon in pure gases in order to obtain a reliable set of cross sections. For N2O, a set has been developed that fits a wide range of data. However, some verification of significant changes in the shape of the attachment cross section should still be done. In two different sets of data for the mixtures of Xe and He and of Ar and N2, the existing cross sections do a very good job throughout most of the energy range, although some small adjustments may be sought at the higher end of the relevant energy range for xenon. In this paper we summarize the work already described in separate papers for each of the He-Xe and Ar-N2 mixtures, and we present here a number of transport coefficients and analyses that were not included in the original papers.

  4. Review of Skin Friction Measurements Including Recent High-Reynolds Number Results from NASA Langley NTF

    NASA Technical Reports Server (NTRS)

    Watson, Ralph D.; Hall, Robert M.; Anders, John B.

    2000-01-01

    This paper reviews flat plate skin friction data from early correlations of drag on plates in water to measurements in the cryogenic environment of The NASA Langley National Transonic Facility (NTF) in late 1996. The flat plate (zero pressure gradient with negligible surface curvature) incompressible skin friction at high Reynolds numbers is emphasized in this paper, due to its importance in assessing the accuracy of measurements, and as being important to the aerodynamics of large scale vehicles. A correlation of zero pressure gradient skin friction data minimizing extraneous effects between tests is often used as the first step in the calculation of skin friction in complex flows. Early data compiled by Schoenherr for a range of momentum thickness Reynolds numbers, R(sub Theta) from 860 to 370,000 contained large scatter, but has proved surprisingly accurate in its correlated form. Subsequent measurements in wind tunnels under more carefully controlled conditions have provided inputs to this database, usually to a maximum R(sub Theta) of about 40,000. Data on a large axisymmetric model in the NASA Langley National Transonic Facility extends the upper limit in incompressible R(sub Theta) to 619,800 using the van Driest transformation. Previous data, test techniques, and error sources ar discussed, and the NTF data will be discussed in detail. The NTF Preston tube and Clauser inferred data accuracy is estimated to be within -2 percent of a power-law curve fit, and falls above the Spalding theory by 1 percent at R(sub Theta) of about 600,000.

  5. Measurement of spatio-temporal transport in live cells

    NASA Astrophysics Data System (ADS)

    Wang, Ru; Wang, Zhuo; Millet, Larry; Gillette, Martha U.; Popescu, Gabriel

    2010-03-01

    The live cell is a highly dynamical system with complicated biophysical and biochemical processes taking place at diverse spatiotemporal scales. Though it is well known that microtubules and actin filaments play important roles in intracellular transport, their dynamic behavior is not entirely understood. We propose a unified approach to studying transport in live cells. We used Spatial Light Interference Microscopy, a quantitative phase imaging method developed in our laboratory, to extract cell mass distributions over broad spatiotemporal scales. The dispersion relations for this transport dynamics, i.e. frequency bandwidth vs. spatial frequencies, reveal deterministic mass transport at large spatial scales (w˜q) and diffusive transport at small spatial scales (w˜q̂2). At submicron scales, we observed a w˜q̂3 behavior, which indicates whip-like movements of protein filaments. Further control experiments where both the microtubule and actin polymerization were blocked suggests that essentially actin governs the long spatial scales behavior and microtubules the short scales. This label-free method enables us to access different components of cell dynamics and quantify diffusion coefficients and speed of motor proteins.

  6. Measurement of electron transport coefficients in tetramethylsilane vapour

    NASA Astrophysics Data System (ADS)

    Yoshida, Kosaku; Mori, S.; Kishimoto, Y.; Ohuchi, H.; Hasegawa, H.; Shimozuma, M.; Tagashira, H.

    2005-06-01

    This paper reports four electron transport coefficients in tetramethylsilane (TMS, Si(CH3)4) vapour which is utilized in plasma-enhanced chemical vapour deposition (PECVD) of thin films such as SiC and SiN. The coefficients, namely the density-normalized effective ionization coefficient (αeff/N), the mean-arrival-time drift velocity (Wm) and the product of the longitudinal electron diffusion coefficient and the gas density (NDL) have been experimentally determined using a double-shutter drift tube method based on an arrival-time spectra theory over a reduced electric field (E/N) range of 30-5000 Td (1 Td = 10-21 V m2). The result shows that the coefficient αeff/N increases rapidly at an E/N value of about 200 Td and then reaches a value of 9.84 × 10-16 cm2 at an E/N value of 5000 Td. It is revealed that the values of the coefficient αeff/N are practically equal to those in SiH4 gas which is a representative gas used in PECVD. The reliability of the αeff/N values is checked by a steady-state Townsend experiment. The drift velocity (Wm) monotonically increases with E/N except at 50 Td < E/N < 200 Td, where a slight negative differential conductivity is observed. The longitudinal diffusion coefficient (NDL) has a minimum value at an E/N value of about 100 Td in the present measurement. Its variation profile against E/N is similar to that in SiH4 although its profile shifts to higher E/N. The ratio of the longitudinal diffusion coefficient to the mobility (DL/μ) is deduced from the Wm and the NDL values, which monotonically increases from 0.1 to about 10 eV with E/N in the present E/N range.

  7. Differences in rating curve and hydrograph uncertainty due to streamflow dynamics and number of discharge measurements

    NASA Astrophysics Data System (ADS)

    Rosenstand Poulsen, Jane; Bering Ovesen, Niels; Larsen, Søren Erik; Tornbjerg, Henrik

    2015-04-01

    The uncertainty related to the use of rating curves for hydrograph estimation is strongly affected if changes in cross-sectional geometry or friction properties occur, especially if the changes are abrupt. In lowland moderately sized streams in temperate regions, such flow changes are often associated with seasonal weed growth. The gradual increase in channel bed roughness caused by weed growth is commonly accounted for by a likewise gradual shift of the rating curve according to monthly discharge measurements. However, this measurement approach is sensitive to abrupt changes in flow, which occur for instance in dynamic streams exhibiting a large difference between maximum and minimum flow or during high summer flows or winter flooding. Hence, the purpose of this study is to investigate the role that dynamic versus stable streams play in terms of uncertainty of establishing rating curves and calculating hydrographs with the traditional stage-discharge approach. Such an analysis is highly valuable in terms of addressing the possibility of adapting hydrograph estimation procedures to the specific streamflow dynamics, thereby quantifying and potentially lowering the uncertainty of hydrograph estimates. Based on results from the Danish national rainfall-runoff model, ratios between yearly median maximum and median minimum stream discharge were calculated for 15 km2 sub-catchments for the entire country. Based on these values, ten gauging stations were selected, located to cover the range of flow regimes represented by the calculated max/min discharge ratios. The selected gauging stations were all stations that had at least three consecutive years with historical data series where direct stream discharge had been measured twenty or more times each year. Based on these data series, new sub-series were created by continuously thinning out the number of discharge measurements. Then, for each of these constructed data series a rating curve and a hydrograph were established according to the Danish standard procedure. After this, a statistical analysis was conducted to evaluate the influence of both flow regime and the number of direct discharge measurements on the deviations and uncertainties of the hydrographs.

  8. Hardware random number generator base on monostable multivibrators dedicated for distributed measurement and control systems

    NASA Astrophysics Data System (ADS)

    Czernik, Pawel

    2013-10-01

    The hardware random number generator based on the 74121 monostable multivibrators for applications in cryptographically secure distributed measurement and control systems with asymmetric resources was presented. This device was implemented on the basis of the physical electronic vibration generator in which the circuit is composed of two "loop" 74121 monostable multivibrators, D flip-flop and external clock signal source. The clock signal, witch control D flip-flop was generated by a computer on one of the parallel port pins. There was presented programmed the author's acquisition process of random data from the measuring system to a computer. The presented system was designed, builded and thoroughly tested in the term of cryptographic security in our laboratory, what there is the most important part of this publication. Real cryptographic security was tested based on the author's software and the software environment called RDieHarder. The obtained results was here presented and analyzed in detail with particular reference to the specificity of distributed measurement and control systems with asymmetric resources.

  9. Detailed Measurements of Turbulent Rayleigh-Taylor Mixing at Large and Small Atwood Numbers

    SciTech Connect

    Malcolm J. Andrews, Ph.D.

    2004-12-14

    This project has two major tasks: Task 1. The construction of a new air/helium facility to collect detailed measurements of Rayleigh-Taylor (RT) mixing at high Atwood number, and the distribution of these data to LLNL, LANL, and Alliance members for code validation and design purposes. Task 2. The collection of initial condition data from the new Air/Helium facility, for use with validation of RT simulation codes at LLNL and LANL. Also, studies of multi-layer mixing with the existing water channel facility. Over the last twelve (12) months there has been excellent progress, detailed in this report, with both tasks. As of December 10, 2004, the air/helium facility is now complete and extensive testing and validation of diagnostics has been performed. Currently experiments with air/helium up to Atwood numbers of 0.25 (the maximum is 0.75, but the highest Reynolds numbers are at 0.25) are being performed. The progress matches the project plan, as does the budget, and we expect this to continue for 2005. With interest expressed from LLNL we have continued with initial condition studies using the water channel. This work has also progressed well, with one of the graduate Research Assistants (Mr. Nick Mueschke) visiting LLNL the past two summers to work with Dr. O. Schilling. Several journal papers are in preparation that describe the work. Two MSc.'s have been completed (Mr. Nick Mueschke, and Mr. Wayne Kraft, 12/1/03). Nick and Wayne are both pursuing Ph.D.s' funded by this DOE Alliances project. Presently three (3) Ph.D. graduate Research Assistants are supported on the project, and two (2) undergraduate Research Assistants. During the year two (2) journal papers and two (2) conference papers have been published, ten (10) presentations made at conferences, and three (3) invited presentations.

  10. Measurements of mass attenuation coefficient, effective atomic number and electron density of some amino acids

    NASA Astrophysics Data System (ADS)

    Kore, Prashant S.; Pawar, Pravina P.

    2014-05-01

    The mass attenuation coefficients of some amino acids, such as DL-aspartic acid-LR(C4H7NO4), L-glutamine (C4H10N2O3), creatine monohydrate LR(C4H9N3O2H2O), creatinine hydrochloride (C4H7N3O·HCl) L-asparagine monohydrate(C4H9N3O2H2O), L-methionine LR(C5H11NO2S), were measured at 122, 356, 511, 662, 1170, 1275 and 1330 keV photon energies using a well-collimated narrow beam good geometry set-up. The gamma-rays were detected using NaI (Tl) scintillation detection system with a resolution of 0.101785 at 662 keV. The attenuation coefficient data were then used to obtain the effective atomic numbers (Zeff), and effective electron densities (Neff) of amino acids. It was observed that the effective atomic number (Zeff) and effective electron densities (Neff) initially decrease and tend to be almost constant as a function of gamma-ray energy. Zeff and Neff experimental values showed good agreement with the theoretical values with less than 1% error for amino acids.

  11. Automated 3D trajectory measuring of large numbers of moving particles.

    PubMed

    Wu, Hai Shan; Zhao, Qi; Zou, Danping; Chen, Yan Qiu

    2011-04-11

    Complex dynamics of natural particle systems, such as insect swarms, bird flocks, fish schools, has attracted great attention of scientists for years. Measuring 3D trajectory of each individual in a group is vital for quantitative study of their dynamic properties, yet such empirical data is rare mainly due to the challenges of maintaining the identities of large numbers of individuals with similar visual features and frequent occlusions. We here present an automatic and efficient algorithm to track 3D motion trajectories of large numbers of moving particles using two video cameras. Our method solves this problem by formulating it as three linear assignment problems (LAP). For each video sequence, the first LAP obtains 2D tracks of moving targets and is able to maintain target identities in the presence of occlusions; the second one matches the visually similar targets across two views via a novel technique named maximum epipolar co-motion length (MECL), which is not only able to effectively reduce matching ambiguity but also further diminish the influence of frequent occlusions; the last one links 3D track segments into complete trajectories via computing a globally optimal assignment based on temporal and kinematic cues. Experiment results on simulated particle swarms with various particle densities validated the accuracy and robustness of the proposed method. As real-world case, our method successfully acquired 3D flight paths of fruit fly (Drosophila melanogaster) group comprising hundreds of freely flying individuals. PMID:21503074

  12. Number of first-passage times as a measurement of information for weakly chaotic systems.

    PubMed

    Nazé, Pierre; Venegeroles, Roberto

    2014-10-01

    We consider a general class of maps of the interval having Lyapunov subexponential instability |δxt|∼|δx0|exp[Λt(x0)ζ(t)], where ζ(t) grows sublinearly as t→∞. We outline here a scheme [J. Stat. Phys. 154, 988 (2014)] whereby the choice of a characteristic function automatically defines the map equation and corresponding growth rate ζ(t). This matching approach is based on the infinite measure property of such systems. We show that the average information that is necessary to record without ambiguity a trajectory of the system tends to 〈Λ〉ζ(t), suitably extending the Kolmogorov-Sinai entropy and Pesin's identity. For such systems, information behaves like a random variable for random initial conditions, its statistics obeying a universal Mittag-Leffler law. We show that, for individual trajectories, information can be accurately inferred by the number of first-passage times through a given turbulent phase-space cell. This enables us to calculate far more efficiently Lyapunov exponents for such systems. Lastly, we also show that the usual renewal description of jumps to the turbulent cell, usually employed in the literature, does not provide the real number of entrances there. Our results are supported by exhaustive numerical simulations. PMID:25375577

  13. Externally driven global Alfvén eigenmodes applied for effective mass number measurement on TCABR

    SciTech Connect

    Puglia, P. G. P. P.; Elfimov, A. G.; Ruchko, L. F.; Galvão, R. M. O.; Guimarães-Filho, Z.; Ronchi, G.

    2014-12-15

    The excitation and detection of Global Alfvén Eigenmodes on TCABR for diagnostic purposes are presented. The modes can be excited with one or two in-vessel antennae, with up to 15 A of current in each, in the frequency range from 2 to 4 MHz. This scheme allows the estimation of the effective mass number at the plasma center, which value is affected by impurity concentration in the core. An amplifier based on MOSFETs is used to excite the waves driven by low power, in order to not change the basic plasma parameters. The variation of the GAE with density is verified and the location of the mode resonance at the plasma center is confirmed by the sawtooth beating, so that the correspondingly beating phase inversion improves the precision on the resonant condition determination. The toroidal parity of the modes N = 1,2 is determined by use of two opposite located antennae with different phase of the RF current. Knowledge of toroidal mode number is important as it identifies GAE location and defines the estimated effective mass value. The estimated value for A{sub eff} is ∼1.4–1.5, corresponding to 5–7% of carbon impurity concentration. The measured value of A{sub eff} is used to estimate Z{sub eff}, which is compared to older TCA experiments and the value obtained by the Spitzer conductivity.

  14. Number of first-passage times as a measurement of information for weakly chaotic systems

    NASA Astrophysics Data System (ADS)

    Nazé, Pierre; Venegeroles, Roberto

    2014-10-01

    We consider a general class of maps of the interval having Lyapunov subexponential instability |δxt|˜|δx0|exp[Λt(x0)ζ(t)], where ζ (t) grows sublinearly as t →∞. We outline here a scheme [J. Stat. Phys. 154, 988 (2014), 10.1007/s10955-013-0895-5] whereby the choice of a characteristic function automatically defines the map equation and corresponding growth rate ζ (t). This matching approach is based on the infinite measure property of such systems. We show that the average information that is necessary to record without ambiguity a trajectory of the system tends to <Λ>ζ(t), suitably extending the Kolmogorov-Sinai entropy and Pesin's identity. For such systems, information behaves like a random variable for random initial conditions, its statistics obeying a universal Mittag-Leffler law. We show that, for individual trajectories, information can be accurately inferred by the number of first-passage times through a given turbulent phase-space cell. This enables us to calculate far more efficiently Lyapunov exponents for such systems. Lastly, we also show that the usual renewal description of jumps to the turbulent cell, usually employed in the literature, does not provide the real number of entrances there. Our results are supported by exhaustive numerical simulations.

  15. Measurements of ultrafine particles carrying different number of charges in on- and near-freeway environments

    NASA Astrophysics Data System (ADS)

    Lee, Eon S.; Xu, Bin; Zhu, Yifang

    2012-12-01

    This paper presents measurements of electrical charges on ultrafine particles (UFPs) of different electrical mobility diameters (30, 50, 80, and 100 nm) in on- and near-freeway environments. Using a tandem Differential Mobility Analyzer (DMA) system, we first examined the fraction of UFPs carrying different number of charges on two distinctive freeways: a gasoline-vehicle dominated freeway (I-405) and a heavy-duty diesel truck dominated freeway (I-710). The fractions of UFPs of a given size carrying one or more charges were significantly higher on the freeways than in the background. The background UFPs only carried up to two charges but freeway UFPs could have up to three charges. The total fraction of charged particles was higher on the I-710 than I-405 across the studied electrical mobility diameters. Near the I-405 freeway, we observed a strong decay of charged particles on the downwind side of the freeway. We also found fractional decay of the charged particles was faster than total particle number concentrations, but slower than total ion concentrations downwind from the freeway I-405. Among charged particles, the highest decay rate was observed for particles carrying three charges. Near the I-710 freeway, we found strong net positive charges on nucleation mode particles, suggesting that UFPs were not at steady-state charge equilibrium near freeways.

  16. Increased number of myocardial blood flow measurements with radionuclide-labeled microspheres

    SciTech Connect

    Baer, R.W.; Payne, B.D.; Verrier, E.D.; Vlahakes, G.J.; Molodowitch, D.; Uhlig, P.N.; Hoffman, J.I.E.

    1984-01-01

    The use of a least-squares radionuclide separation technique to allow an increased number of myocardial blood flow measurements with radionuclide-labeled microspheres in dogs was evaluated. Two sets of labeled macrospheres were studied: a set of eight labeled with /sup 125/I, /sup 153/Gd, /sup 57/Co, /sup 51/Cr, /sup 113/Sn, /sup 85/Sr, /sup 95/Nb, and /sup 46/Sc; and a set of nine in which /sup 125/I, and /sup 46/Sc were replaced with /sup 114/In, /sup 54/Mn, and /sup 65/Zn. For each microsphere label the nuclide activities determined by least-squares separation compared favorably with those actually added to in vitro samples containing a fixed amount of the other nuclides in the set. For the set of eight radionuclide-labeled microspheres, myocardial flow measurements made with the least-squares separation technique and the reference sample method were usually within 15% and almost all within 20% of direct measurements of coronary venous outflow in a right heart bypass preparation. Serial left atrial injections of 15-..mu..m microspheres totaling 48 x 10/sup 6/ caused no significant changes in systemic hemodynamics, regional myocardial flows, or coronary pressure-flow relations, whether the coronary bed was autorelating or vasodilated with chromonar. It was concluded that at least nine myocardial blood flow measurements can be made in dogs with acceptable accuracy and without evidence of dysfunction due to embolization of the coronary vascular bed. With appropriate validation, this method should be applicable to other organs and animal models as well. 32 references.

  17. Aerosol Formation and Aging: Insights from the Combination of Chemical Transport Models and Measurements

    NASA Astrophysics Data System (ADS)

    Pandis, Spyros; Fountoukis, Christos; Megaritis, Athanasios; Kiari, Kalliopi; Pilinis, Chris; Karnezi, Heleni; Patoulias, David; Skyllakou, Ksakousti; Murphy, Benjamin

    2014-05-01

    The field measurements that have taken place in the PEGASOS and other European projects (ACTRIS, EUCAARI) offer a unique opportunity to test our understanding of a series of processes related to the formation and atmospheric evolution of atmospheric particulate matter. We combine the predictions of the Chemical Transport Model PMCAMx focusing on particle mass composition distribution and its sister model PMCAMx-UF focusing on particle number with these measurements over Europe. We first quantify our ability to reproduce the observed levels of the major PM components and their precursors in a variety of environments and meteorological conditions. In the second step we test the models further examining the diurnal profiles of the various PM components, the oxygen content (a measure of the chemical aging) of organic aerosol, and the vertical distribution. We focus especially on the various processes responsible for the chemical evolution of the OA in the atmosphere and test a number of hypotheses regarding their rates and specifics. The interactions between these organic aerosol processes and the growth of ultrafine particles formed in the atmosphere are investigated.

  18. A framework for operationalization of strategic plans and metrics for corporate performance measurement in transportation asset management

    NASA Astrophysics Data System (ADS)

    Mteri, Hassan H.

    This thesis investigated the business processes required to translate corporate-level strategic plans into tactical and operational plans in the context of transportation asset management. The study also developed a framework for effective performance measure for departments of transportation. The thesis was based on a case study of transportation agencies in the U.S.A. and Canada. The scope is therefore limited or more directly applicable to transportation assets such as pavement, bridges and culverts. The goal was to address the problem of translating or managing strategic plans, especially in the context of the public sector responsible for operating transportation infrastructure. It was observed that many agencies have been successful in formulating good strategic plans but they have performed relatively poorly in translating such corporate-level strategic plans into operational activities. A questionnaire survey was designed and targeted about 30 state agencies that are currently active in transportation asset management. Twenty one (21) transportation agencies in the USA and Canada responded to the questionnaire. The analysis of the questionnaire data showed that there is a lack of a standard approach to managing corporate strategic plans in transportation agencies. The results also indicated that most transportation agencies operate in three organizational levels but there was no systematic approach of translating goal and objectives from high level to lower levels. Approaches in performance measurement were found to vary from agency to agency. A number of limitations were identified in the existing practice on performance measurements. Key weaknesses include the large number of measures in use (as many as 25 or more), and the disconnection between the measures used and the corporate goals and objectives. Lessons from the private sector were thoroughly reviewed in order to build the groundwork for adapting existing tools to the public sector. The existing literature, assumptions and characteristics that make the Balanced Scorecards and strategy maps work effectively in the private sector were identified. Gaps in implementation of strategic plans and the use of Balanced Scorecard in the public sector were derived. Although Balanced Scorecards have previously been used to a limited extent in transportation agencies, the use of combined Balanced Scorecards and strategy maps with a much broader utility of translating strategic plans into tactical and operational activities for Transportation Asset Management is yet to be established. The thesis presents a framework to operationalize strategic plans through the combined application of Balanced Scorecards and strategy maps. The proposed framework aligns overarching objectives in all organizational levels: corporate, tactical, and operation, in which detail information is delegated from top level to lower levels. Furthermore, the thesis presents a proposed framework for developing and using effective corporate performance measures. The framework for performance measures provides a key tool for tracking progress and ensuring overall operationalization of strategic plans in transportation agencies. The thesis presents a methodology to assess existing performance measures so that agencies can reduce the number of measures, to be more effective and manageable. It was found that among other good characteristics, corporate performance measures must be tied to agency's goals and objectives and must be sensitive or responsive to program delivery activities and to the impacts of decisions about resource allocation.

  19. TRANSPORTATION-RELATED VOLATILE HYDROCARBON SOURCE PROFILES MEASURED IN ATLANTA

    EPA Science Inventory

    Samples representative of transportation-related hydrocarbon missions were collected as part of the 1990 "Atlanta Ozone Precursor Monitoring Study". otor vehicle emissions were sampled in canisters beside a roadway in a tunnel-like underpass during periods of heavy traffic. irpor...

  20. The Measurement of the Number of Light Neutrino Species at LEP

    NASA Astrophysics Data System (ADS)

    Mele, Salvatore

    2015-07-01

    Within weeks of the start of the data taking at the LEP accelerator, the ALEPH, DELPHI, L3 and OPAL experiments were able to confirm the existence of just three light neutrino species. This measurement relies on the Standard Model relation between the `invisible' width of the Z-boson and the cross-sections for Z-boson production and subsequent decay into hadrons. The full data sample collected by the experiments at and around the Z-boson resonance allows a high-precision measurement of the number of light neutrino species as 2.9840 ± 0.0082. The uncertainty is mostly due to the understanding of the low-angle Bhabha scattering process used to determine the experimental luminosity. This result is independently confirmed by the elegant direct observation of the e^-e^+ to ν bar{ν}γ process, through the detection of an initial-state-radiation photon in otherwise empty detectors. This result confirms expectations from the existence of three charged leptons species, and contributes to the fields of astrophysics and cosmology. Alongside other LEP achievements, the precision of this result is a testament to the global cooperation underpinning CERN's fourth decade. LEP saw the onset of large-scale collaboration across experiments totaling over 2000 scientists, together with a strong partnership within the wider high-energy physics community: from accelerator operations to the understanding of theoretical processes.

  1. Low Reynolds number wind tunnel measurements - The importance of being earnest

    NASA Technical Reports Server (NTRS)

    Mueller, Thomas J.; Batill, Stephen M.; Brendel, Michael; Perry, Mark L.; Bloch, Diane R.

    1986-01-01

    A method for obtaining two-dimensional aerodynamic force coefficients at low Reynolds numbers using a three-component external platform balance is presented. Regardless of method, however, the importance of understanding the possible influence of the test facility and instrumentation on the final results cannot be overstated. There is an uncertainty in the ability of the facility to simulate a two-dimensional flow environment due to the confinement effect of the wind tunnel and the method used to mount the airfoil. Additionally, the ability of the instrumentation to accurately measure forces and pressures has an associated uncertainty. This paper focuses on efforts taken to understand the errors introduced by the techniques and apparatus used at the University of Notre Dame, and, the importance of making an earnest estimate of the uncertainty. Although quantitative estimates of facility induced errors are difficult to obtain, the uncertainty in measured results can be handled in a straightforward manner and provide the experimentalist, and others, with a basis to evaluate experimental results.

  2. The measurement of O2 number density by absorption of Lyman alpha

    NASA Technical Reports Server (NTRS)

    Smith, L. G.; Miller, K. L.

    1974-01-01

    Measurements of O2 number density obtained from rocket observations of the absorption profile of solar Lyman alpha (1216 A) have been compared with values derived from nearly simultaneous measurements of atmospheric density from other rocket techniques: grenades, falling sphere, and Pitot tube. All launches were from Wallops Island, Virginia. The atmospheric density derived from the absorption spectroscopy data is found to be about 20% less than that from the other techniques when a constant value of the absorption cross section of 1.0 times 10 to the minus 20th sq cm is used. The agreement is worse when the cross section is allowed to vary across the width of the solar line. The data in the altitude range 70-90 km are interpreted as showing that the effective value of the absorption cross section at Lyman alpha for O2 at 200 K and negligible pressure is about 0.8 times 10 to the minus 20th sq cm.

  3. Utilizing photon number parity measurements to demonstrate quantum computation with cat-states in a cavity

    NASA Astrophysics Data System (ADS)

    Petrenko, A.; Ofek, N.; Vlastakis, B.; Sun, L.; Leghtas, Z.; Heeres, R.; Sliwa, K. M.; Mirrahimi, M.; Jiang, L.; Devoret, M. H.; Schoelkopf, R. J.

    2015-03-01

    Realizing a working quantum computer requires overcoming the many challenges that come with coupling large numbers of qubits to perform logical operations. These include improving coherence times, achieving high gate fidelities, and correcting for the inevitable errors that will occur throughout the duration of an algorithm. While impressive progress has been made in all of these areas, the difficulty of combining these ingredients to demonstrate an error-protected logical qubit, comprised of many physical qubits, still remains formidable. With its large Hilbert space, superior coherence properties, and single dominant error channel (single photon loss), a superconducting 3D resonator acting as a resource for a quantum memory offers a hardware-efficient alternative to multi-qubit codes [Leghtas et.al. PRL 2013]. Here we build upon recent work on cat-state encoding [Vlastakis et.al. Science 2013] and photon-parity jumps [Sun et.al. 2014] by exploring the effects of sequential measurements on a cavity state. Employing a transmon qubit dispersively coupled to two superconducting resonators in a cQED architecture, we explore further the application of parity measurements to characterizing such a hybrid qubit/cat state architecture. In so doing, we demonstrate the promise of integrating cat states as central constituents of future quantum codes.

  4. Scaling of elliptic flow in heavy-ion collisions with the number of constituent quarks in a transport model

    NASA Astrophysics Data System (ADS)

    Singha, Subhash; Nasim, Md.

    2016-03-01

    We studied the number of constituent quark scaling (NCQ) behavior of elliptic flow (v2) under the framework of a multiphase transport model (AMPT) at both top-RHIC and LHC energies. The NCQ-scaling in v2 holds at top RHIC energy with AMPT string melting version, while it breaks in Pb+Pb collisions at LHC energy using the same framework. The breaking of NCQ scaling at LHC energy has been studied by varying the magnitude of parton-parton scattering cross sections and lifetime of hadronic cascade as implemented in AMPT. We find that the breaking of NCQ scaling in Pb+Pb collisions at √{sNN}=2.76 TeV is independent of the magnitude of parton-parton cross sections and the later stage hadronic interactions. Further we observed that scaling holds in a small collision system like Si+Si at √{sNN}=2.76 TeV. We discussed that the breaking of NCQ scaling is possibly due to high phase-space density of constituents quarks in Pb+Pb collisions at √{sNN}=2.76 TeV.

  5. Measurement and modeling of phosphorous transport in shallow groundwater environments.

    PubMed

    Hendricks, G S; Shukla, S; Obreza, T A; Harris, W G

    2014-08-01

    Leaching of phosphorus (P) from agricultural soils, especially those that are sandy, is adversely impacting P-limited ecosystems like Florida's Everglades. A more developed understanding of P and water management strategies and their effects on P leaching is needed to achieve reductions in subsurface P losses, especially from intensively managed dual cropping systems under plastic mulch in shallow water regions. We compared the effects of conservation P and water management strategies with traditional practices on P transport to groundwater. A 3-year experiment was conducted on hydrologically isolated plots with plastic-mulched successive cropping systems to compare high (HEI) and soil test based recommended (REI) external input (water and fertilizer P) systems with traditional sub-irrigation (seepage), and REI with a potential water conservation subsurface drip irrigation system (REI-SD) with regard to groundwater P concentrations above and below the low conductivity spodic horizon (Bh). The REI treatments had higher available storage for rainfall and P than HEI. Use of both REI systems (REI=2098μg/L and REI-SD=2048μg/L) reduced groundwater P concentrations above the Bh horizon by 33% compared to HEI (3090μg/L), and results were significant at the 0.05 level. Although the subsurface drip system saved water, it did not offer any groundwater quality (P) benefit. Mixing and dilution of influent P below the low conductivity Bh horizon between treatments and with the regional groundwater system resulted in no significant differences in groundwater P concentration below the Bh horizon. Groundwater P concentrations from this study were higher than reported elsewhere due to low soil P storage capacity (SPSC), high hydraulic conductivity of sandy soils, and a high water table beneath crop beds. The HEI system leached more P due to ferilizer P in excess of SPSC and used higher irrigation volumes compared with REI systems. Despite a 40% difference in the average amount of added fertilizer P between HEI (187kg P2O5/ha) and REI (124kg P2O5/ha), soil Mehlich 1 P (M1P) values were similar for both systems while they received Pinput. Soil M1P for REI and REI-SD increased to a maximum of 55mg/kg while they received Pinput, and then gradually decreased after Pinput ceased. However, M1P for HEI increased steadily to a maximum of 145mg/kg by the end of the study with continued Pinput. Mehlich-1 P measured six years after the study still showed relatively high levels of P, a legacy effect of Pinput. The main factors influencing groundwater P concentration varied by seasons. During fall with frequent rainfall, the concentrations were influenced mainly by M1P and Pinput, and highlight a need for greater focus on Pinput management (vs. water management) during this season. However, during the dry period of spring, a greater focus on irrigation management is required since depth to water table and rainfall also become contributing factors. Three multivariate models (r(2)=0.67 to 0.93), for spring, fall, and annual periods, were developed for predicting groundwater P concentrations for a wide range of water and P inputs (0 to 191kg P2O5/ha of Pinput). The uniqueness of these models is that they use readily available hydrologic (rainfall and water table depth), management (Pinput), and soil (M1P) data commonly monitored by growers when managing water and nutrient inputs on agricultural landscapes. The development of similar models may not be necessary for other agro-ecosystems in similar regions since long-term data collected in these regions may be applied, with verification, to the models presented here. PMID:24981965

  6. Measurement and modeling of phosphorous transport in shallow groundwater environments

    NASA Astrophysics Data System (ADS)

    Hendricks, G. S.; Shukla, S.; Obreza, T. A.; Harris, W. G.

    2014-08-01

    Leaching of phosphorus (P) from agricultural soils, especially those that are sandy, is adversely impacting P-limited ecosystems like Florida's Everglades. A more developed understanding of P and water management strategies and their effects on P leaching is needed to achieve reductions in subsurface P losses, especially from intensively managed dual cropping systems under plastic mulch in shallow water regions. We compared the effects of conservation P and water management strategies with traditional practices on P transport to groundwater. A 3-year experiment was conducted on hydrologically isolated plots with plastic-mulched successive cropping systems to compare high (HEI) and soil test based recommended (REI) external input (water and fertilizer P) systems with traditional sub-irrigation (seepage), and REI with a potential water conservation subsurface drip irrigation system (REI-SD) with regard to groundwater P concentrations above and below the low conductivity spodic horizon (Bh). The REI treatments had higher available storage for rainfall and P than HEI. Use of both REI systems (REI = 2098 μg/L and REI-SD = 2048 μg/L) reduced groundwater P concentrations above the Bh horizon by 33% compared to HEI (3090 μg/L), and results were significant at the 0.05 level. Although the subsurface drip system saved water, it did not offer any groundwater quality (P) benefit. Mixing and dilution of influent P below the low conductivity Bh horizon between treatments and with the regional groundwater system resulted in no significant differences in groundwater P concentration below the Bh horizon. Groundwater P concentrations from this study were higher than reported elsewhere due to low soil P storage capacity (SPSC), high hydraulic conductivity of sandy soils, and a high water table beneath crop beds. The HEI system leached more P due to ferilizer P in excess of SPSC and used higher irrigation volumes compared with REI systems. Despite a 40% difference in the average amount of added fertilizer P between HEI (187 kg P2O5/ha) and REI (124 kg P2O5/ha), soil Mehlich 1 P (M1P) values were similar for both systems while they received Pinput. Soil M1P for REI and REI-SD increased to a maximum of 55 mg/kg while they received Pinput, and then gradually decreased after Pinput ceased. However, M1P for HEI increased steadily to a maximum of 145 mg/kg by the end of the study with continued Pinput. Mehlich-1 P measured six years after the study still showed relatively high levels of P, a legacy effect of Pinput. The main factors influencing groundwater P concentration varied by seasons. During fall with frequent rainfall, the concentrations were influenced mainly by M1P and Pinput, and highlight a need for greater focus on Pinput management (vs. water management) during this season. However, during the dry period of spring, a greater focus on irrigation management is required since depth to water table and rainfall also become contributing factors. Three multivariate models (r2 = 0.67 to 0.93), for spring, fall, and annual periods, were developed for predicting groundwater P concentrations for a wide range of water and P inputs (0 to 191 kg P2O5/ha of Pinput). The uniqueness of these models is that they use readily available hydrologic (rainfall and water table depth), management (Pinput), and soil (M1P) data commonly monitored by growers when managing water and nutrient inputs on agricultural landscapes. The development of similar models may not be necessary for other agro-ecosystems in similar regions since long-term data collected in these regions may be applied, with verification, to the models presented here.

  7. Measurement of Black Carbon and Particle Number Emission Factors from Individual Heavy-Duty Trucks

    SciTech Connect

    Ban-Weiss, George A.; Lunden, Melissa M.; Kirchstetter, Thomas W.; Harley, Robert A.

    2009-02-02

    Emission factors for black carbon (BC) and particle number (PN) were measured from 226 individual heavy-duty (HD) diesel-fueled trucks driving through a 1 km-long California highway tunnel in August 2006. Emission factors were based on concurrent increases in BC, PN, and CO{sub 2}B concentrations (measured at 1 Hz) that corresponded to the passage of individual HD trucks. The distributions of BC and PN emission factors from individual HD trucks are skewed, meaning that a large fraction of pollution comes from a small fraction of the in-use vehicle fleet. The highest-emitting 10% of trucks were responsible for {approx} 40% of total BC and PN emissions from all HD trucks. BC emissions were log-normally distributed with a mean emission factor of 1.7 g kg {sup -1} and maximum values of {approx} 10 g kg{sup -1}. Corresponding values for PN emission factors were 4.7 x 10{sup 15} and 4 x 10{sup 16} kg{sup -1}. There was minimal overlap among high-emitters of these two pollutants: only 1 of the 226 HD trucks measured was found to be among the highest 10% for both BC and PN. Monte Carlo resampling of the distribution of BC emission factors observed in this study revealed that uncertainties (1{sigma}) in extrapolating from a random sample of n HD trucks to a population mean emission factor ranged from {+-} 43% for n = 10 to {+-} 8% for n = 300, illustrating the importance of sufficiently large vehicle sample sizes in emissions studies. Studies with low sample sizes are also more easily biased due to misrepresentation of high-emitters. As vehicles become cleaner on average in future years, skewness of the emissions distributions will increase, and thus sample sizes needed to extrapolate reliably from a subset of vehicles to the entire in-use vehicle fleet are expected to become more of a challenge.

  8. Apparatus for the measurement of radionuclide transport rates in rock cores

    SciTech Connect

    Weed, H.C.; Koszykowski, R.F.; Dibley, L.L.; Murray, I.

    1981-09-01

    An apparatus and procedure for the study of radionuclide transport in intact rock cores are presented in this report. This equipment more closely simulates natural conditions of radionuclide transport than do crushed rock columns. The apparatus and the procedure from rock core preparation through data analysis are described. The retardation factors measured are the ratio of the transport rate of a non-retarded radionuclide, such as /sup 3/H, to the transport rate of a retarded radionuclide. Sample results from a study of the transport of /sup 95m/Tc and /sup 85/Sr in brine through a sandstone core are included.

  9. Inverse constraints for emission fluxes of atmospheric tracers estimated from concentration measurements and Lagrangian transport

    NASA Astrophysics Data System (ADS)

    Pisso, Ignacio; Patra, Prabir; Breivik, Knut

    2015-04-01

    Lagrangian transport models based on times series of Eulerian fields provide a computationally affordable way of achieving very high resolution for limited areas and time periods. This makes them especially suitable for the analysis of point-wise measurements of atmospheric tracers. We present an application illustrated with examples of greenhouse gases from anthropogenic emissions in urban areas and biogenic emissions in Japan and of pollutants in the Arctic. We asses the algorithmic complexity of the numerical implementation as well as the use of non-procedural techniques such as Object-Oriented programming. We discuss aspects related to the quantification of uncertainty from prior information in the presence of model error and limited number of observations. The case of non-linear constraints is explored using direct numerical optimisation methods.

  10. Combining impact sensor field and laboratory flume measurements with other techniques for studying fluvial bedload transport in steep mountain streams

    NASA Astrophysics Data System (ADS)

    Beylich, Achim A.; Laute, Katja

    2014-08-01

    The timing and rate of fluvial bedload transport are of central importance within sediment budget studies and in many applications in river science and engineering. During the years 2010, 2011 and 2012 detailed field measurements with portable impact sensors as a non-invasive technique for indirectly determining fluvial bedload transport intensity were conducted in two instrumented and supply-limited drainage basin systems (Erdalen and Bødalen) in the fjord landscape in western Norway. Additional field measurements with portable impact sensors were carried out in 2010 and 2011 in selected transport-limited fluvial systems in the Coast Mountains of western Canada. The collected impact sensor field data were calibrated with laboratory flume experiments. The data from the impact sensor field measurements in western Norway and the flume experiments were combined with field data from continuous discharge monitoring, repeated surveys of channel morphometry and sediment texture, particle tracer measurements, Helley-Smith samplings, underwater video filming and biofilm analyses. The combination of methods and techniques applied provides insights into the temporal variability and intensity of fluvial bedload transport in the selected mountain streams: (i) in the transport-limited systems with generally high bedload transport rates during high discharge and with bedload material moving in clusters over the impact sensor plates, impact sensor data (based on a 1 s measuring interval) provide the opportunity to detect the start and end of bedload transport, thus to identify discharge thresholds for sediment entrainment, and to roughly estimate the intensity and relative intensity of change of bedload transport during the measuring period; (ii) in the supply-limited systems with low bedload transport rates and bedload components moving separately (as single particles) over the impact sensor plates, impact sensor data (with a 1 s measuring interval) allow the detection of the start and end of transport of bedload components > 11.3 mm, thus the identification of discharge thresholds for possible entrainment of particles, the quantification of the number of particles > 11.3 mm moving over the impact sensor plates during the measuring period, the rough estimation of grain sizes of the particles moving separately over the impact sensor plates, and the calculation of the total mass of the bedload material > 11.3 mm moving over the impact sensor plates during the measuring period; (iii) when combined with other methods and techniques (Helley-Smith sampling, particle tracer measurements, biofilm analyses, underwater video filming) which provide information on the active bedload transport channel width, on discharge thresholds for possible entrainment of particles of different grain sizes, and on transport rates of bedload material < 11.3 mm, total rates of fluvial bedload transport, covering all given grain sizes of the bedload material, can be calculated for the supply-limited mountain streams with generally low bedload transport. The higher measured annual bedload yield in Bødalen (13.6 t km- 2 yr- 1) compared to Erdalen (2.6 t km- 2 yr- 1) reflects a higher level of slope-channel coupling in Bødalen than in Erdalen.

  11. A method for the measurement and analysis of ride vibrations of transportation systems

    NASA Technical Reports Server (NTRS)

    Catherines, J. J.; Clevenson, S. A.; Scholl, H. F.

    1972-01-01

    The measurement and recording of ride vibrations which affect passenger comfort in transportation systems and the subsequent data-reduction methods necessary for interpreting the data present exceptional instrumentation requirements and necessitate the use of computers for specialized analysis techniques. A method is presented for both measuring and analyzing ride vibrations of the type encountered in ground and air transportation systems. A portable system for measuring and recording low-frequency, low-amplitude accelerations and specialized data-reduction procedures are described. Sample vibration measurements in the form of statistical parameters representative of typical transportation systems are also presented to demonstrate the utility of the techniques.

  12. Time-Resolved Measurements of Suprathermal Ion Transport Induced by Intermittent Plasma Blob Filaments

    NASA Astrophysics Data System (ADS)

    Bovet, A.; Fasoli, A.; Furno, I.

    2014-11-01

    Suprathermal ion turbulent transport in magnetized plasmas is generally nondiffusive, ranging from subdiffusive to superdiffusive depending on the interplay of the turbulent structures and the suprathermal ion orbits. Here, we present time-resolved measurements of the cross-field suprathermal ion transport in a toroidal magnetized turbulent plasma. Measurements in the superdiffusive regime are characterized by a higher intermittency than in the subdiffusive regime. Using conditional averaging, we show that, when the transport is superdiffusive, suprathermal ions are transported by intermittent field-elongated turbulent structures that are radially propagating.

  13. Modeling and measurement of the variations of CT number distributions for mobile targets in cone-beam computed tomographic imaging.

    PubMed

    Ali, Imad; Alsbou, Nesreen; Ahmad, Salahuddin

    2015-01-01

    The purpose of this study was to investigate quantitatively by measurement and modeling the variations in CT number distributions of mobile targets in cone-beam CT (CBCT) imaging. CBCT images were acquired for three targets manufactured from homogenous water-equivalent gel that was inserted into a commercial mobile thorax phantom. The phantom moved with a controlled cyclic motion in one-dimension along the superior-inferior direction to simulate patient respiratory motion. Profiles of the CT number distributions of the static and mobile targets were obtained using CBCT images. A mathematical model was developed that predicted the variations in CT number distributions and their dependence on the motion parameters of targets moving in one-dimension using CBCT imaging. The measured CT number distributions for the mobile targets varied considerably, depending on the motion parameters. The extension of the CT number distribution increased linearly with motion amplitude where maximum target elongation reached twice the motion amplitude. The CT number levels of the mobile targets were smeared over a longer distribution; for example, the CT number level for the 20 mm target dropped by nearly 30% at motion amplitude (A) equal to 20 mm in comparison with the CT number distribution of stationary targets. Frequency of motion played an important role in spatial and level variations of the CT number distributions. For example, the level of the CT number profile for the medium target (20 mm) decreased evenly by nearly 50% at A = 20 mm with high motion frequencies. Motion phase did not affect the CT number distributions for prolonged projection acquisition that included several respiratory cycles. The mathematical model of the CT number distributions of mobile targets in CBCT reproduced well the measured CT number distributions and predicted their dependence on the target size and phantom motion parameters such as speed, amplitude, frequency, and phase. The CT number distributions varied considerably with motion in CBCT. A motion model of CT number distribution for mobile targets has been developed in this work that predicted well the variations in the measured CT number profiles and their dependence on motion parameters. The model corrected the CT number distribution retrospective to CT image reconstruction where it used a first-order linear relationship between the number of projections collected in the imaging window of a mobile voxel to obtain the cumulative CT number. This model provides quantitative characterization of motion artifacts on CT number distributions in CBCT that is useful to determine the validity of CT numbers and the accuracy of localization and volume measurement of tumors in diagnostic imaging and interventional applications, such as radiotherapy. PMID:25679162

  14. Electrical transport measurements on honeycomb artificial spin ice.

    NASA Astrophysics Data System (ADS)

    Zeissler, Katharina; Chadha, Megha; Cohen, Lesley; Branford, Will; Functional Magnetism Group Team

    2014-03-01

    Artificial spin ice is a macroscopic playground for magnetically frustrated systems. We have previously shown that in a cobalt honeycomb artificial spin ice composed of 1 micron long nanowires there are unusual features in the magnetotransport below 50K. Here we explore the low temperature transport of equivalent artificial spin ice structures fabricated from permalloy. We discuss the extent to which the phenomenon is generic to the honeycomb artificial spin ice geometry and the effect of changing the constituent material on the onset temperature and the magnitude of the magnetotransport effect.

  15. Measurement of lentiviral vector titre and copy number by cross-species duplex quantitative PCR.

    PubMed

    Christodoulou, I; Patsali, P; Stephanou, C; Antoniou, M; Kleanthous, M; Lederer, C W

    2016-01-01

    Lentiviruses are the vectors of choice for many preclinical studies and clinical applications of gene therapy. Accurate measurement of biological vector titre before treatment is a prerequisite for vector dosing, and the calculation of vector integration sites per cell after treatment is as critical to the characterisation of modified cell products as it is to long-term follow-up and the assessment of risk and therapeutic efficiency in patients. These analyses are typically based on quantitative real-time PCR (qPCR), but as yet compromise accuracy and comparability between laboratories and experimental systems, the former by using separate simplex reactions for the detection of endogene and lentiviral sequences and the latter by designing different PCR assays for analyses in human cells and animal disease models. In this study, we validate in human and murine cells a qPCR system for the single-tube assessment of lentiviral vector copy numbers that is suitable for analyses in at least 33 different mammalian species, including human and other primates, mouse, pig, cat and domestic ruminants. The established assay combines the accuracy of single-tube quantitation by duplex qPCR with the convenience of one-off assay optimisation for cross-species analyses and with the direct comparability of lentiviral transduction efficiencies in different species. PMID:26202078

  16. Thermoelectric Transport Measurements of Graphene on hBN

    NASA Astrophysics Data System (ADS)

    Duan, Junxi; Wang, Xiaoming; Li, Guohong; Lai, Xinyuan; Zebarjadi, Mona; Andrei, Eva Y.

    The unique electronic transport properties of graphene, arising from massless charge carriers whose sign and density can be tuned by gating, have been studied extensively. Much less work was devoted to graphene's thermal properties. Unlike electrical transport which depends on total carrier density, the thermopower is determined by the net charge transferred and not by the carrier density. This leads to profound differences between the two phenomena. For example, when the Fermi level is close to the Dirac point (DP) where electron-hole (e-h) puddles are populated symmetrically, the electron and hole contributions to the thermopower cancel out. In contrast, their contributions to the electrical current add up. We studied the thermoelectric properties of high quality graphene supported on an hBN substrate, where the e-h puddle regime is significantly reduced compared to that on SiO2 substrates, which allows closer access to the DP. At room temperature we find that the maximum Seebeck coefficient close to the DP reaches up to twice the values on SiO2 substrates. Upon cooling down to 77K it decreases in a non-linear fashion with temperature. We will discuss possible origins of this behavior. Work Supported by DOE-FG02-99ER45742, NSF DMR 1207108 and FA9550-14-1-0316.

  17. Spray washing, absorbent cornstarch powder, and dry time to reduce bacterial numbers on soiled transport cage flooring

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Broiler transport cages are often used repeatedly without washing and fecal matter deposited on the floor surface can transfer Campylobacter from one flock to another. Allowing feces to dry is an effective but slow and logistically impractical means to kill Campylobacter in soiled transport cages. ...

  18. Measurement of off-diagonal transport coefficients in two-phase flow in porous media.

    PubMed

    Ramakrishnan, T S; Goode, P A

    2015-07-01

    The prevalent description of low capillary number two-phase flow in porous media relies on the independence of phase transport. An extended Darcy's law with a saturation dependent effective permeability is used for each phase. The driving force for each phase is given by its pressure gradient and the body force. This diagonally dominant form neglects momentum transfer from one phase to the other. Numerical and analytical modeling in regular geometries have however shown that while this approximation is simple and acceptable in some cases, many practical problems require inclusion of momentum transfer across the interface. Its inclusion leads to a generalized form of extended Darcy's law in which both the diagonal relative permeabilities and the off-diagonal terms depend not only on saturation but also on the viscosity ratio. Analogous to application of thermodynamics to dynamical systems, any of the extended forms of Darcy's law assumes quasi-static interfaces of fluids for describing displacement problems. Despite the importance of the permeability coefficients in oil recovery, soil moisture transport, contaminant removal, etc., direct measurements to infer the magnitude of the off-diagonal coefficients have been lacking. The published data based on cocurrent and countercurrent displacement experiments are necessarily indirect. In this paper, we propose a null experiment to measure the off-diagonal term directly. For a given non-wetting phase pressure-gradient, the null method is based on measuring a counter pressure drop in the wetting phase required to maintain a zero flux. The ratio of the off-diagonal coefficient to the wetting phase diagonal coefficient (relative permeability) may then be determined. The apparatus is described in detail, along with the results obtained. We demonstrate the validity of the experimental results and conclude the paper by comparing experimental data to numerical simulation. PMID:25748636

  19. Mahler measure of the Horie unit and Weber's Class Number Problem in the Cyclotomic Zp-extension of Q

    NASA Astrophysics Data System (ADS)

    Morisawa, Takayuki

    2010-07-01

    Let p be a prime number. It is an interesting problem to consider whether a prime number ℓ divides the class numbers of the intermediate fields of the cyclotomic Zp-extension of Q. In the case p = 2, R. Okazaki developed a theory for this problem by using Mahler measure. In this paper, we focus on the case p = 3 and show that a prime number ℓ does not divide the class numbers of the intermediate fields of the cyclotomic Z33-extension of Q if ℓ satisfies ℓ≢±1 mod 27.

  20. Air transport flight parameter measurements program - Concepts and benefits

    NASA Technical Reports Server (NTRS)

    Morris, G. J.; Crabill, N. L.

    1980-01-01

    A program is described in which statistical flight loads and operating practice data for both narrow- and wide-body airline transport aircraft, intended primarily for use by manufacturers in updating design criteria, are obtained from existing, on-board digital flight data recorders. Procedures for editing and processing the data are explained, and differences between these and past NACA/NASA analog data are discussed. One major such difference is the automatic bandpass filtering of normal acceleration data to separate high-frequency gust response from low-frequency maneuver response. Plans and preliminary efforts for the development of an on-board data processing system, able to derive statistical aircraft operating parameters directly from real-time data, are also reviewed.

  1. Electronic measurement of strain effects on spin transport in silicon

    NASA Astrophysics Data System (ADS)

    Qing, Lan; Tinkey, Holly; Appelbaum, Ian

    Spin transport in silicon is limited by the Elliott-Yafet spin relaxation mechanism, which is driven by scattering between degenerate conduction band valleys. Mechanical strain along a valley axis partially breaks this degeneracy, and will ultimately quench intervalley spin relaxation for transitions between states on orthogonal axes. Using a custom-designed and constructed strain probe, we study the effects of uniaxial compressive strain along the < 100 > direction on ballistic tunnel junction devices used to inject spin-polarized electrons into silicon. The effects of strain-induced valley splitting will be presented and compared to our theoretical model. This work is supported by the Office of Naval Research under Contract No. N000141410317, the National Science Foundation under Contract No. ECCS-1231855, the Defense Threat Reduction Agency under Contract No. HDTRA1-13-1-0013, and the Maryland NanoCenter.

  2. [What measures can be taken to reduce the number of smoking adolescents and young women?].

    PubMed

    Errard-Lalande, G; Halimi, A

    2005-04-01

    A proper understanding of the factors exposing adolescents and young women to the risk of smoking dependence is necessary to develop effective preventive measures. These measures will be different depending on whether they are designed for adolescents and young women in general or for the context of pregnancy. For adolescents, efforts should be continued to provide information about smoking and the dangers of tobacco as well as about the social manipulation involved. The image of a natural, active woman, free of tobacco and capable of making her own decisions should be promoted. Health education and communication professionals should make use of different media with an audience among the young. Messages should be validated with a target population before diffusion. A better coherence between the adult and young populations concerning legal obligations and mutual respect is significantly useful. Educational structures (schools and universities) should participate in long-term community projects implicating peer groups and trained professionals. Values which should be reinforced include self-esteem, affirmation of personal competence and difference, self-respect and respect of others. Early identification of factors favoring psychosocial vulnerability at this age is indispensable to facilitate referral to professional support and care centers, the number of which remains insufficient to date. Support when ceasing smoking, based on individual and group assistance, should take into account the individual's phase of maturation, and must be proposed and operated by trained professionals working in a network. During pregnancy, it is crucial to recognize that the woman's specific physical and psychological situation is a unique opportunity to propose a new approach to smoking, taking into consideration the fragile context during this period of maturation and its impact on the woman's general life. Beyond sociopolitical measures and a philosophical debate on the position of women, men, and the family in the 21st century, propositions can be put forward for actions before, during and after the maternity period. It is important to continue the educational aspect without creating a guilt feeling. Messages should be elaborated with women. Healthcare professionals should be trained about smoking and smoking dependence. They should repeat minimal advice and continuously propose stopping smoking, taking into consideration the woman's stage of maturation and her motivation. Carbon monoxide monitoring should become a routine practice. Prognostic factors and possible difficulties should be identified early, if possible before pregnancy or at least during pregnancy, in order to propose adapted multidisciplinary support. The health booklet for the mother and the infant should be improved. Midwives should play an important role in prevention. A multidisciplinary effort will have the greatest impact: smoke-free environment in maternities, professional clinics, and the real-life territory of the pregnant woman. Individual care and support are more appropriate than group support. The partner should be implicated. For very dependent women, basically psychological support of smoking cessation should be completed with nicotine substitution therapy using protocols which should be redefined with more extensive studies. All these measures should be continued for six months after birth whether the woman has stopped smoking during pregnancy or not. PMID:15980805

  3. Validation of bed-load transport measurements with time-sequenced bathymetric data

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Advances in bathymetric data acquisition have made it possible to adopt a new, expedient method for measuring bed load transport in rivers. The method consists of comparing time sequenced bathymetric data sets and utilizing a simple mass conservation relation for bed load transport. Assuming a tri...

  4. Measurement of the atom number distribution in an optical tweezer using single-photon counting

    SciTech Connect

    Fuhrmanek, A.; Sortais, Y. R. P.; Grangier, P.; Browaeys, A.

    2010-08-15

    We demonstrate in this paper a method to reconstruct the atom number distribution of a cloud containing a few tens of cold atoms. The atoms are first loaded from a magneto-optical trap into a microscopic optical dipole trap and then released in a resonant light probe where they undergo a Brownian motion and scatter photons. We count the number of photon events detected on an image intensifier. Using the response of our detection system to a single atom as a calibration, we extract the atom number distribution when the trap is loaded with more than one atom. The atom number distribution is found to be compatible with a Poisson distribution.

  5. From computing with numbers to computing with words. From manipulation of measurements to manipulation of perceptions.

    PubMed

    Zadeh, L A

    2001-04-01

    Interest in issues relating to consciousness has grown markedly during the last several years. And yet, nobody can claim that consciousness is a well-understood concept that lends itself to precise analysis. It may be argued that, as a concept, consciousness is much too complex to fit into the conceptual structure of existing theories based on Aristotelian logic and probability theory. An approach suggested in this paper links consciousness to perceptions and perceptions to their descriptors in a natural language. In this way, those aspects of consciousness which relate to reasoning and concept formation are linked to what is referred to as the methodology of computing with words (CW). Computing, in its usual sense, is centered on manipulation of numbers and symbols. In contrast, computing with words, or CW for short, is a methodology in which the objects of computation are words and propositions drawn from a natural language (e.g., small, large, far, heavy, not very likely, the price of gas is low and declining, Berkeley is near San Francisco, it is very unlikely that there will be a significant increase in the price of oil in the near future, etc.). Computing with words is inspired by the remarkable human capability to perform a wide variety of physical and mental tasks without any measurements and any computations. Familiar examples of such tasks are parking a car, driving in heavy traffic, playing golf, riding a bicycle, understanding speech, and summarizing a story. Underlying this remarkable capability is the brain's crucial ability to manipulate perceptions--perceptions of distance, size, weight, color, speed, time, direction, force, number, truth, likelihood, and other characteristics of physical and mental objects. Manipulation of perceptions plays a key role in human recognition, decision and execution processes. As a methodology, computing with words provides a foundation for a computational theory of perceptions: a theory which may have an important bearing on how humans make--and machines might make--perception-based rational decisions in an environment of imprecision, uncertainty, and partial truth. A basic difference between perceptions and measurements is that, in general, measurements are crisp, whereas perceptions are fuzzy. One of the fundamental aims of science has been and continues to be that of progressing from perceptions to measurements. Pursuit of this aim has led to brilliant successes. We have sent men to the moon; we can build computers that are capable of performing billions of computations per second; we have constructed telescopes that can explore the far reaches of the universe; and we can date the age of rocks that are millions of years old. But alongside the brilliant successes stand conspicuous underachievements and outright failures. We cannot build robots that can move with the agility of animals or humans; we cannot automate driving in heavy traffic; we cannot translate from one language to another at the level of a human interpreter; we cannot create programs that can summarize non-trivial stories; our ability to model the behavior of economic systems leaves much to be desired; and we cannot build machines that can compete with children in the performance of a wide variety of physical and cognitive tasks. It may be argued that underlying the underachievements and failures is the unavailability of a methodology for reasoning and computing with perceptions rather than measurements. An outline of such a methodology--referred to as a computational theory of perceptions--is presented in this paper. The computational theory of perceptions (CTP) is based on the methodology of CW. In CTP, words play the role of labels of perceptions, and, more generally, perceptions are expressed as propositions in a natural language. CW-based techniques are employed to translate propositions expressed in a natural language into what is called the Generalized Constraint Language (GCL). In this language, the meaning of a proposition is expressed as a generalized constraint, X isr R, where X is the constrained variable, R is the constraining relation, and isr is a variable copula in which r is an indexing variable whose value defines the way in which R constrains X. Among the basic types of constraints are possibilistic, veristic, probabilistic, random set, Pawlak set, fuzzy graph, and usuality. The wide variety of constraints in GCL makes GCL a much more expressive language than the language of predicate logic. In CW, the initial and terminal data sets, IDS and TDS, are assumed to consist of propositions expressed in a natural language. These propositions are translated, respectively, into antecedent and consequent constraints. Consequent constraints are derived from antecedent constraints through the use of rules of constraint propagation. The principal constraint propagation rule is the generalized extension principle. (ABSTRACT TRUNCATED) PMID:11357866

  6. Measurements of fluctuating pressure in a rectangular cavity in transonic flow at high Reynolds numbers

    NASA Technical Reports Server (NTRS)

    Tracy, M. B.; Plentovich, E. B.; Chu, Julio

    1992-01-01

    An experiment was performed in the Langley 0.3 meter Transonic Cryogenic Tunnel to study the internal acoustic field generated by rectangular cavities in transonic and subsonic flows and to determine the effect of Reynolds number and angle of yaw on the field. The cavity was 11.25 in. long and 2.50 in. wide. The cavity depth was varied to obtain length-to-height (l/h) ratios of 4.40, 6.70, 12.67, and 20.00. Data were obtained for a free stream Mach number range from 0.20 to 0.90, a Reynolds number range from 2 x 10(exp 6) to 100 x 10(exp 6) per foot with a nearly constant boundary layer thickness, and for two angles of yaw of 0 and 15 degs. Results show that Reynolds number has little effect on the acoustic field in rectangular cavities at angle of yaw of 0 deg. Cavities with l/h = 4.40 and 6.70 generated tones at transonic speeds, whereas those with l/h = 20.00 did not. This trend agrees with data obtained previously at supersonic speeds. As Mach number decreased, the amplitude, and bandwidth of the tones changed. No tones appeared for Mach number = 0.20. For a cavity with l/h = 12.67, tones appeared at Mach number = 0.60, indicating a possible change in flow field type. Changes in acoustic spectra with angle of yaw varied with Reynolds number, Mach number, l/h ratios, and acoustic mode number.

  7. Laser transit-time measurements between earth and moon with a transportable system

    NASA Technical Reports Server (NTRS)

    Lehr, C. G.; Criswell, S. J.; Ouellette, J. P.; Sozanski, P. W.; Mulholland, J. D.; Shelus, P. J.

    1973-01-01

    A high radiance, pulsed laser system with a transportable transmitting unit was used to measure the transit times of 25 ns, 10 joule, and 530 nm pulses from earth to the Apollo 15 retroreflector on the moon and back.

  8. Flight and wind-tunnel measurements showing base drag reduction provided by a trailing disk for high Reynolds number turbulent flow for subsonic and transonic Mach numbers

    NASA Technical Reports Server (NTRS)

    Powers, Sheryll Goecke; Huffman, Jarrett K.; Fox, Charles H., Jr.

    1986-01-01

    The effectiveness of a trailing disk, or trapped vortex concept, in reducing the base drag of a large body of revolution was studied from measurements made both in flight and in a wind tunnel. Pressure data obtained for the flight experiment, and both pressure and force balance data were obtained for the wind tunnel experiment. The flight test also included data obtained from a hemispherical base. The experiment demonstrated the significant base drag reduction capability of the trailing disk to Mach 0.93 and to Reynolds numbers up to 80 times greater than for earlier studies. For the trailing disk data from the flight experiment, the maximum decrease in base drag ranged form 0.08 to 0.07 as Mach number increased from 0.70 to 0.93. Aircraft angles of attack ranged from 3.9 to 6.6 deg for the flight data. For the trailing disk data from the wind tunnel experiment, the maximum decrease in base and total drag ranged from 0.08 to 0.05 for the approximately 0 deg angle of attack data as Mach number increased from 0.30 to 0.82.

  9. Disordered Fermi liquid in epitaxial graphene from quantum transport measurements.

    PubMed

    Lara-Avila, Samuel; Tzalenchuk, Alexander; Kubatkin, Sergey; Yakimova, Rositza; Janssen, T J B M; Cedergren, Karin; Bergsten, Tobias; Fal'ko, Vladimir

    2011-10-14

    We have performed magnetotransport measurements on monolayer epitaxial graphene and analyzed them in the framework of the disordered Fermi liquid theory. We have separated the electron-electron and weak-localization contributions to resistivity and demonstrated the phase coherence over a micrometer length scale, setting the limit of at least 50 ps on the spin relaxation time in this material. PMID:22107411

  10. MEASUREMENT OF LIGHT HYDROCARBONS AND OXIDANT TRANSPORT, HOUSTON AREA 1976

    EPA Science Inventory

    An extensive air pollutant monitoring program, including ground level and aerial sampling, was carried out in the Houston area during the month of July 1976. Measurements included ozone, oxides of nitrogen, PAN, methane, carbon monoxide, individual hydrocarbons (C2-C10), halocarb...

  11. Measuring urea persistence, distribution and transport on coastal plain soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The persistence and mobility of urea, an organic form of nitrogen present in animal manures and commercial fertilizers, has rarely been studied and measured, because it is assumed to undergo rapid hydrolysis to ammonia. However, preliminary studies have shown urea to exist in leachate and runoff sev...

  12. TR-PIV measurement of the wake behind a grooved cylinder at low Reynolds number

    NASA Astrophysics Data System (ADS)

    Liu, Ying Zheng; Shi, Liu Liu; Yu, Jun

    2011-04-01

    A comparative study of the wakes behind cylinders with grooved and smooth surfaces was performed with a view to understand the wake characteristics associated with the adult Saguaro cacti. A low-speed recirculation water channel was established for the experiment; the Reynolds number, based on the free-stream velocity and cylinder diameter (D), was kept at ReD=1500. State-of-the-art time-resolved particle image velocimetry (TR-PIV) was employed to measure a total of 20 480 realizations of the wake field at a frame rate of 250 Hz, enabling a comprehensive view of the time- and phase-averaged wake pattern. In comparison to the wake behind the smooth cylinder, the length of the recirculation zone behind the grooved cylinder was extended by nearly 18.2%, yet the longitudinal velocity fluctuation intensity was considerably weakened. A global view of the peaked spectrum of the longitudinal velocity component revealed that the intermediate region for the grooved cylinder, which approximately corresponds to the transition region where the shear layer vortices interact, merge and shed before the formation of the Karman-like vortex street, was much wider than that for the smooth one. The unsteady events near St=0.3-0.4 were detected in the intermediate region behind the grooved cylinder, but no such events were found in the smooth cylinder system. Although the formation of the Karman-like vortex street was delayed by about 0.6D downstream for the grooved cylinder, no prominent difference in the vortex street region was found in the far wake for both cylinders. The Proper Orthogonal Decomposition (POD) method was used extensively to decompose the vector and swirling strength fields, which gave a close-up view of the vortices in the near wake. The first two POD modes of the swirling strength clarified the spatio-temporal characteristics of the shear layer vortices behind the grooved cylinder. The small-scale vortices superimposed on the shear layers behind the grooved cylinder were found to be generated and convected downstream in the same phase, which would significantly reduce the fluctuating force on the cylinder surface.

  13. Measurement of effective atomic number of gunshot residues using scattering of gamma rays

    NASA Astrophysics Data System (ADS)

    Yılmaz, Demet; Turşucu, Ahmet; Uzunoğlu, Zeynep; Korucu, Demet

    2014-09-01

    Better understanding of gunshot residues and the major elemental composition would be valuable to forensic scientists for their analysis work and interpretation of results. In the present work, the effective atomic numbers of gunshot residues (cartridge case, bullet core, bullet jacket and gunpowder) were analyzed using energy dispersive X-ray analysis (EDX). The scattering of 59.54 keV gamma rays is studied using a high-resolution HPGe detector. The experiment is performed on various elements with atomic number in the 4≤Z≤82. The intensity ratio of coherent to Compton scattered peaks, corrected for photo-peak efficiency of gamma detector and absorption of photons in the sample and air, is plotted as a function of atomic number and constituted a best-fit-curve. From this fit-curve, the respective effective atomic numbers of gunshot residues are determined.

  14. TRANSPORT

    EPA Science Inventory

    Presentation outline: transport principles, effective solubility; gasoline composition; and field examples (plume diving).
    Presentation conclusions: MTBE transport follows from - phyiscal and chemical properties and hydrology. Field examples show: MTBE plumes > benzene plu...

  15. In-Situ Measurements of Engineered Nanoporous Particle Transport in Saturated Porous Media

    SciTech Connect

    Shang, Jianying; Liu, Chongxuan; Wang, Zheming; Wu, Hong; Zhu, Kake; Li, Juan; Liu, Jun

    2010-10-28

    Engineered nanoporous particles have become an important class of nano-structured materials that have found their increasing industrial, energy, and environmental applications. The internal pore surfaces in the particles can be chemically tailored to sequestrate metals and radionuclide contaminants from groundwater. The fate and transport of the nanoporous particles in subsurface environments, however, have not been studied. Here we present a scanning optical fiber fluorescence profiler that can be used to in situ measure the transport of fluorescence-tagged colloidal and nano-structured particles in column systems. Engineered nanoporous silicate particles (ENSPs) that were covalently bonded with fluorescence-emitting, and uranium-chelating ligands in the intraparticle pore domains were synthesized and used as an example to investigate the nanoporous particle transport and to demonstrate the application of the developed in situ measurement profiler. The profiler detected an irreversible or slowly detached fraction of ENSPs in the sand collector even under conditions thermodynamically unfavorable to particle attachment. Further, the in situ measurement system detected the spatial variability of ENSPs transport that deviated from one-dimensional, homogeneous assumption that is typically used to model particle transport in the column. Generally, however, both measured and model-calculated results indicated that the transport of ENSPs were consistent with that of nonporous colloidal particles that subjected to coupled reversible attachment/detachment and straining processes. The developed system can also be applied to detect other fluorescence-tagged nano-structured or colloidal particle transport.

  16. Electrophoretic NMR measurements of lithium transference numbers in polymer gel electrolytes

    SciTech Connect

    Dai, H.; Sanderson, S.; Davey, J.; Uribe, F.; Zawodzinski, T.A. Jr.

    1997-05-01

    Polymer gel electrolytes are of increasing interest for plastic lithium batteries largely because of their high room temperature conductivity. Several studies have probed their conductivity and electrochemical stability but very little work has been done related to lithium transference numbers. Lithium ion transference numbers, the net number of Faradays carried by lithium upon the passage of 1 Faraday of charge across a cell, are key figures of merit for any potential lithium battery electrolytes. The authors describe here their application of electrophoretic NMR (ENMR) to the determination of transference numbers of lithium ions in polymer gel electrolytes. Two types of polymer gel electrolytes were selected for this study: PAN/PC/EC/LiX and Kynar/PC/LiX. Results obtained for the two types of gels are compared and the effects of anion, polymer-ion interactions and ion-ion interactions on lithium transference numbers are discussed. Significant differences in the behavior of transference numbers with salt concentration are observed for the two types of gels. This may be due to the extent of interaction between the polymer and the ions. Implications for solid polymer electrolytes are discussed.

  17. Measured and simulated electron thermal transport in the Madisom symmetric torus reversed field pinch

    NASA Astrophysics Data System (ADS)

    Rodrigue Mbombo, Brice

    New high time resolution measurements of the evolution of the electron temperature profile through a sawtooth event in high current reversed-field pinch (RFP) discharges in the Madison Symmetric Torus (MST) have been made using the enhanced capabilities of the multipoint, multi-pulse Thomson scattering system. Using this and other data, the electron thermal diffusion chie determined and is found to vary by orders of magnitude over the course of the sawtooth cycle. This experimental data is compared directly to simulations run at experimentally relevant parameters. This includes zero beta, single fluid, nonlinear, resistive magnetohydrodynamic (MHD) simulations run with the aspect ratio, resistivity profile, and Lundquist number (S ˜ 4 x 106) of high current RFP discharges in MST. These simulations display MHD activity and sawtooth like behavior similar to that observed in the MST. This includes both the sawtooth period and the duration of the sawtooth crash. The radial shape of the magnetic mode amplitudes, scaled to match edge measurements made in MST, are then used to compute the expected level of thermal diffusion due to parallel losses along diffusing magnetic field lines, chiMD = upsilon∥Dmag. The evolution of the Dmag profile was determined for over 20 sawteeth so that the ensemble averaged evolution could be compared to the sawtooth ensembled data from MST. The resulting comparison to the measured chi e shows that chiMD is larger than chi e at most times. However, if electrons are trapped in a magnetic well, they cannot carry energy along the diffusing magnetic field lines, reducing the thermal transport. Accounting for trapped particles brings chi MD to within uncertainty of chie in the mid radius at most times throughout the sawtooth cycle. In the core, the measured chie is greater than chi MD leading up to and including the sawtooth crash, suggesting other transport mechanisms are important at these times. Additionally, in a simulation including pressure evolution, a striking agreement is found between the temperature fluctuations seen in the simulation and those previously measured in MST. This work supported by the US DOE and NSF.

  18. Analysis of Fluctuating Static Pressure Measurements in a Large High Reynolds Number Transonic Cryogenic Wind Tunnel. Ph.D. Thesis

    NASA Technical Reports Server (NTRS)

    Igoe, William B.

    1991-01-01

    Dynamic measurements of fluctuating static pressure levels were made using flush mounted high frequency response pressure transducers at eleven locations in the circuit of the National Transonic Facility (NTF) over the complete operating range of this wind tunnel. Measurements were made at test section Mach numbers from 0.2 to 1.2, at pressure from 1 to 8.6 atmospheres and at temperatures from ambient to -250 F, resulting in dynamic flow disturbance measurements at the highest Reynolds numbers available in a transonic ground test facility. Tests were also made independently at variable Mach number, variable Reynolds number, and variable drivepower, each time keeping the other two variables constant thus allowing for the first time, a distinct separation of these three important variables. A description of the NTF emphasizing its flow quality features, details on the calibration of the instrumentation, results of measurements with the test section slots covered, downstream choke, effects of liquid nitrogen injection and gaseous nitrogen venting, comparisons between air and nitrogen, isolation of the effects of Mach number, Reynolds number, and fan drive power, and identification of the sources of significant flow disturbances is included. The results indicate that primary sources of flow disturbance in the NTF may be edge-tones generated by test section sidewall re-entry flaps and the venting of nitrogen gas from the return leg of the tunnel circuit between turns 3 and 4 in the cryogenic mode of operation. The tests to isolate the effects of Mach number, Reynolds number, and drive power indicate that Mach number effects predominate. A comparison with other transonic wind tunnels shows that the NTF has low levels of test section fluctuating static pressure especially in the high subsonic Mach number range from 0.7 to 0.9.

  19. Spatially resolved ballistic optoelectronic transport measured by quantized photocurrent spectroscopy.

    PubMed

    Hof, Klaus-Dieter; Kaiser, Franz J; Stallhofer, Markus; Schuh, Dieter; Wegscheider, Werner; Hänggi, Peter; Kohler, Sigmund; Kotthaus, Jörg P; Holleitner, Alexander W

    2010-10-13

    GaAs-based quantum point contacts (QPCs) are exploited to spatially resolve and analyze the ballistic, nonequilibrium flow of photogenerated electrons in a nanoscale circuit. Electron-hole pairs are photogenerated in a two-dimensional electron gas (2DEG), and the resulting current through an adjacent QPC is measured as a function of the laser spot position. The transmission of photogenerated electrons through the QPC is governed by the energy dispersion and the quantized momentum values of the electron modes in the QPC. PMID:20853822

  20. Large-eddy-simulation and measurements of turbulent transport and mixing in a confined rectangular jet

    NASA Astrophysics Data System (ADS)

    Hill, James; Nilsen, Katrine; Kong, Bo; Olsen, Michael; Fox, Rodney

    2012-11-01

    Large-eddy simulations of transport and mixing of a passive scalar were performed for a confined rectangular liquid jet (Re = 20,000) and compared to results of simultaneous particle image velocimetry and planar laser induced fluorescence measurements. Reasonably good agreement was obtained for single-point statistics as well as for two-point correlation functions of the turbulent velocity, scalar, and joint velocity-scalar fields. Of particular interest was the determination of the diagonal and off-diagonal components of the turbulent diffusivity tensor, the mis-alignment of turbulent fluxes and mean gradients, and determination of the turbulent Schmidt number, with reasonably good agreement between the simulations and experiments. Some of the results are consistent with the measurements of Tavoularis & Corrsin (JFM 104, 331-367 (1981)) for a homogeneous turbulent shear flow with a uniform mean temperature gradient. In our case we find the ratio of diffusivities to range from 1 to 2 (the latter value in agreement with Tavoularis), Sct generally between 0.5 and 1, and the angle between turbulent flux and mean scalar gradient from 120 to 150 degrees.

  1. Measurement of plasma current dependent changes in impurity transport and comparison with nonlinear gyrokinetic simulationa)

    NASA Astrophysics Data System (ADS)

    Howard, N. T.; Greenwald, M.; Mikkelsen, D. R.; White, A. E.; Reinke, M. L.; Ernst, D.; Podpaly, Y.; Candy, J.

    2012-05-01

    Measured impurity transport coefficients are found to demonstrate a strong dependence on plasma current in the core of Alcator C-Mod. These measurements are compared directly with linear and nonlinear gyrokinetic simulation in an attempt to both qualitatively and quantitatively reproduce the measured impurity transport. Discharges constituting a scan of plasma current from 0.6 to 1.2 MA were performed during the 2010 run campaign. The impurity transport from these discharges was determined using a novel set of spectroscopic diagnostics available on Alcator C-Mod. This diagnostic suite allowed for the effective constraint of impurity transport coefficient profiles inside of r/a = 0.6. A decrease in the measured impurity diffusivity and inward convection is found with increased plasma current. Global, nonlinear gyrokinetic simulations were performed using the GYRO code [J. Candy and R. E. Waltz, J Comput. Phys. 186, 545 (2003)] for all discharges in the experimental scan and are found to reproduce the experimental trends, while demonstrating good quantitative agreement with measurement. A more comprehensive quantitative comparison was performed on the 0.8 MA discharge of the current scan which demonstrates that simultaneous agreement between experiment and simulation in both the impurity particle transport and ion heat transport channels is attainable within experimental uncertainties.

  2. Tritium transport, influx, and helium ash measurements on TFTR during DT operation

    SciTech Connect

    Efthimion, P.C.; Johnson, L.C.; Skinner, C.H.

    1994-12-01

    The evolution of the tritium density profile is inferred from 14.1 MeV t(d,n){alpha} and 2.5 MeV d(d,n){sup 3}He neutron emissivity profiles measured in a deuterium neutral beam heated plasma into which a small amount of tritium gas has been puffed. For the first time, hydrogenic ion transport coefficients in the form of a diffusivity and convective velocity are determined. The particle diffusivities of tritium and {sup 4}He, and the deuterium thermal diffusivity are of similar magnitudes, and thus are consistent with theoretically calculated ExB drift transport. The first measurements of helium ash have been made using charge exchange recombination spectroscopy (CHERS). The measured radial ash profile shape is consistent with that predicted from simulations that include calculations of the central alpha ash source and thermal ash transport. This suggests that ash transport in the plasma core will not be a fundamental limiting factor in determining helium exhaust rates in a reactor. The authors also report the first spectroscopic measurements of tritium Balmer-alpha emission which provided a measure of tritium influx from the limiter. Tritium influx persists in discharges subsequent to tritium neutral beam injection, decaying with an initial decay of 7.5 discharges, and followed by a long term decay on the order of 400 discharges. Tritium transport, influx, and helium ash transport are important issues concerning profile control, retention, and ash removal for future reactors, like ITER.

  3. Measurement of plasma current dependent changes in impurity transport and comparison with nonlinear gyrokinetic simulation

    SciTech Connect

    Howard, N. T.; Greenwald, M.; White, A. E.; Reinke, M. L.; Ernst, D.; Podpaly, Y.; Mikkelsen, D. R.; Candy, J.

    2012-05-15

    Measured impurity transport coefficients are found to demonstrate a strong dependence on plasma current in the core of Alcator C-Mod. These measurements are compared directly with linear and nonlinear gyrokinetic simulation in an attempt to both qualitatively and quantitatively reproduce the measured impurity transport. Discharges constituting a scan of plasma current from 0.6 to 1.2 MA were performed during the 2010 run campaign. The impurity transport from these discharges was determined using a novel set of spectroscopic diagnostics available on Alcator C-Mod. This diagnostic suite allowed for the effective constraint of impurity transport coefficient profiles inside of r/a = 0.6. A decrease in the measured impurity diffusivity and inward convection is found with increased plasma current. Global, nonlinear gyrokinetic simulations were performed using the GYRO code [J. Candy and R. E. Waltz, J Comput. Phys. 186, 545 (2003)] for all discharges in the experimental scan and are found to reproduce the experimental trends, while demonstrating good quantitative agreement with measurement. A more comprehensive quantitative comparison was performed on the 0.8 MA discharge of the current scan which demonstrates that simultaneous agreement between experiment and simulation in both the impurity particle transport and ion heat transport channels is attainable within experimental uncertainties.

  4. Estimation of Apollo Lunar Dust Transport using Optical Extinction Measurements

    NASA Astrophysics Data System (ADS)

    Lane, John E.; Metzger, Philip T.

    2015-04-01

    A technique to estimate mass erosion rate of surface soil during landing of the Apollo Lunar Module (LM) and total mass ejected due to the rocket plume interaction is proposed and tested. The erosion rate is proportional to the product of the second moment of the lofted particle size distribution N(D), and third moment of the normalized soil size distribution S(D), divided by the integral of S(D)ṡD2/v(D), where D is particle diameter and v(D) is the vertical component of particle velocity. The second moment of N(D) is estimated by optical extinction analysis of the Apollo cockpit video. Because of the similarity between mass erosion rate of soil as measured by optical extinction and rainfall rate as measured by radar reflectivity, traditional NWS radar/rainfall correlation methodology can be applied to the lunar soil case where various S(D) models are assumed corresponding to specific lunar sites.

  5. Minimum number of trials required for within- and between-session reliability of TMS measures of corticospinal excitability.

    PubMed

    Goldsworthy, M R; Hordacre, B; Ridding, M C

    2016-04-21

    Transcranial magnetic stimulation (TMS)-elicited motor-evoked potentials (MEPs) exhibit considerable trial-to-trial variability, potentially reducing the sensitivity and reproducibility of this measure. While increasing the number of trials will improve accuracy, prolonged recording blocks are not always feasible. In this study, we investigated the minimum number of trials required to provide a measure of human corticospinal excitability that is stable both within and between sessions. Single-pulse TMS was applied to the left primary motor cortex, and MEPs were recorded from the right first dorsal interosseous muscle. Approximately 20-30 trials were required to provide a stable measure of MEP amplitude with high within- and between-session reliability. Extending the number of trials beyond 30 provided no additional benefit. Collecting 30 trials may be optimal for reliably estimating corticospinal excitability using TMS. These findings may have significant implications for using TMS to measure corticospinal excitability in both basic and clinical research settings. PMID:26872998

  6. Measurements of the number density of water molecules in plasma by using a combined spectral-probe method

    NASA Astrophysics Data System (ADS)

    Bernatskiy, A. V.; Ochkin, V. N.; Afonin, O. N.; Antipenkov, A. B.

    2015-09-01

    A novel method for measuring the number density of water molecules in low-temperature plasma is developed. The absolute intensities of rotational lines of the (0,0) band of the OH( A 2Σ- X 2П) transition are used. Lines with sufficiently large rotational quantum numbers referring to the so-called "hot" group of molecules produced by electron-impact dissociative excitation of water molecules are chosen for measurements. The excitation rate of a process with a known cross section is determined by measuring the parameters of plasma electrons by means of the probe method. The measured number densities of molecules are compared with those in the initial plasma-forming mixture. The time evolution of the particle densities in plasma is investigated. The problems of the sensitivity and applicability of the absolute spectral method are considered.

  7. Measurements of the number density of water molecules in plasma by using a combined spectral−probe method

    SciTech Connect

    Bernatskiy, A. V. Ochkin, V. N.; Afonin, O. N.; Antipenkov, A. B.

    2015-09-15

    A novel method for measuring the number density of water molecules in low-temperature plasma is developed. The absolute intensities of rotational lines of the (0,0) band of the OH(A{sup 2}Σ–X{sup 2}Π) transition are used. Lines with sufficiently large rotational quantum numbers referring to the so-called “hot” group of molecules produced by electron-impact dissociative excitation of water molecules are chosen for measurements. The excitation rate of a process with a known cross section is determined by measuring the parameters of plasma electrons by means of the probe method. The measured number densities of molecules are compared with those in the initial plasma-forming mixture. The time evolution of the particle densities in plasma is investigated. The problems of the sensitivity and applicability of the absolute spectral method are considered.

  8. Measurements of the wall-normal velocity component in very high Reynolds number pipe flow

    NASA Astrophysics Data System (ADS)

    Vallikivi, Margit; Hultmark, Marcus; Smits, Alexander J.

    2012-11-01

    Nano-Scale Thermal Anemometry Probes (NSTAPs) have recently been developed and used to study the scaling of the streamwise component of turbulence in pipe flow over a very large range of Reynolds numbers. This probe has an order of magnitude higher spatial and temporal resolution than regular hot wires, allowing it to resolve small scale motions at very high Reynolds numbers. Here use a single inclined NSTAP probe to study the scaling of the wall normal component of velocity fluctuations in the same flow. These new probes are calibrated using a method that is based on the use of the linear stress region of a fully developed pipe flow. Results on the behavior of the wall-normal component of velocity for Reynolds numbers up to 2 million are reported. Supported under NR Grant N00014-09-1-0263 (program manager Ron Joslin) and NSF Grant CBET-1064257 (program manager Henning Winter).

  9. MEASUREMENTS AND COMPUTATIONS OF FUEL DROPLET TRANSPORT IN TURBULENT FLOWS

    SciTech Connect

    Joseph Katz and Omar Knio

    2007-01-10

    The objective of this project is to study the dynamics of fuel droplets in turbulent water flows. The results are essential for development of models capable of predicting the dispersion of slightly light/heavy droplets in isotropic turbulence. Since we presently do not have any experimental data on turbulent diffusion of droplets, existing mixing models have no physical foundations. Such fundamental knowledge is essential for understanding/modeling the environmental problems associated with water-fuel mixing, and/or industrial processes involving mixing of immiscible fluids. The project has had experimental and numerical components: 1. The experimental part of the project has had two components. The first involves measurements of the lift and drag forces acting on a droplet being entrained by a vortex. The experiments and data analysis associated with this phase are still in progress, and the facility, constructed specifically for this project is described in Section 3. In the second and main part, measurements of fuel droplet dispersion rates have been performed in a special facility with controlled isotropic turbulence. As discussed in detail in Section 2, quantifying and modeling the of droplet dispersion rate requires measurements of their three dimensional trajectories in turbulent flows. To obtain the required data, we have introduced a new technique - high-speed, digital Holographic Particle Image Velocimetry (HPIV). The technique, experimental setup and results are presented in Section 2. Further information is available in Gopalan et al. (2005, 2006). 2. The objectives of the numerical part are: (1) to develop a computational code that combines DNS of isotropic turbulence with Lagrangian tracking of particles based on integration of a dynamical equation of motion that accounts for pressure, added mass, lift and drag forces, (2) to perform extensive computations of both buoyant (bubbles) and slightly buoyant (droplets) particles in turbulence conditions relevant to the experiments, and (3) to explore whether the corresponding predictions can explain the experimentally-observed behavior of the rise and dispersion of oil droplets in isotropic turbulence. A brief summary of results is presented in Section 4.

  10. Resonant Acoustic Measurement of Vapor Phase Transport Phenomenon

    NASA Astrophysics Data System (ADS)

    Schuhmann, R. J.; Garrett, S. L.; Matson, J. V.

    2002-12-01

    A major impediment to accurate non steady-state diffusion measurements is the ability to accurately measure and track a rapidly changing gas concentration without disturbing the system. Non-destructive methods that do not interfere with system dynamics have been developed in the past. These methods, however, have tended to be cumbersome or inaccurate at low concentrations. A new experimental approach has been developed to measure gaseous diffusion in free air and through porous materials. The method combines the traditional non steady-state laboratory methodology with resonant acoustic gas analysis. A phase-locked-loop (PLL) resonance frequency tracker is combined with a thermally insulated copper resonator. A piston sealed with a metal bellows excites the fundamental standing wave resonance of the resonator. The PLL maintains a constant phase difference (typically 90) between the accelerometer mounted on the piston and a microphone near the piston to track the resonance frequency in real time. A capillary or glass bead filled core is fitted into an o-ring sealed opening at the end of the resonator opposite the bellows. The rate at which the tracer gas is replaced by air within the resonator is controlled by the diffusion coefficient of the gas in free air through the capillary (DA) or by the effective diffusion coefficient of the gas through the core (De). The mean molecular weight of the gas mixture in the resonator is directly determined six times each minute from the ratio of the absolute temperature to the square of the fundamental acoustic resonance frequency. Average system stability (temperature divided by frequency squared) is better than 350 ppm. DA values for a 0.3-inch diameter capillary were in excellent agreement with published values. De values for porous media samples (0.5 mm glass beads) of four different lengths (1 through 4 inches) using three different tracer gases (He, CH4, Kr) will be reported. Comments will be offered regarding tracer gas selection and device orientation and their effect on experimental results. [Work supported by the Office of Naval Research.

  11. Dynamic simulation of the moving boundary method for measuring transference numbers

    NASA Astrophysics Data System (ADS)

    Zhurov, Konstantin; Dickinson, Edmund J. F.; Compton, Richard G.

    2011-09-01

    The Nernst-Planck-Poisson (NPP) finite difference method is used to simulate a moving boundary experiment of an aqueous system with HCl and CdCl 2 salts, as used to determine the transference number of H + according to the classical method [D.A. MacInnes et al., Chem. Rev. 11 (1932) 171-230]. Theoretical predictions used in inferring transference numbers from moving boundary experiments are confirmed, and the presence of charge separation in the vicinity of the moving boundary is demonstrated. This is the first simulation of the moving boundary experiment using a full NPP scheme.

  12. Measuring intestinal fluid transport in vitro: Gravimetric method versus non-absorbable marker.

    PubMed

    Whittamore, Jonathan M; Genz, Janet; Grosell, Martin; Wilson, Rod W

    2016-04-01

    The gut sac is a long-standing, widely used in vitro preparation for studying solute and water transport, and calculation of these fluxes requires an accurate assessment of volume. This is commonly determined gravimetrically by measuring the change in mass over time. While convenient this likely under-estimates actual net water flux (Jv) due to tissue edema. We evaluated whether the popular in vivo volume marker [(14)C]-PEG 4000, offers a more representative measure of Jvin vitro. We directly compared these two methods in five teleost species (toadfish, flounder, rainbow trout, killifish and tilapia). Net fluid absorption by the toadfish intestine based on PEG was significantly higher, by almost 4-fold, compared to gravimetric measurements, compatible with the latter under-estimating Jv. Despite this, PEG proved inconsistent for all of the other species frequently resulting in calculation of net secretion, in contrast to absorption seen gravimetrically. Such poor parallelism could not be explained by the absorption of [(14)C]-PEG (typically <1%). We identified a number of factors impacting the effectiveness of PEG. One was adsorption to the surface of sample tubes. While it was possible to circumvent this using unlabelled PEG 4000, this had a deleterious effect on PEG-based Jv. We also found sequestration of PEG within the intestinal mucus. In conclusion, the short-comings associated with the accurate representation of Jv by gut sac preparations are not overcome by [(14)C]-PEG. The gravimetric method therefore remains the most reliable measure of Jv and we urge caution in the use of PEG as a volume marker. PMID:26794612

  13. Electrical Noise and the Measurement of Absolute Temperature, Boltzmann's Constant and Avogadro's Number.

    ERIC Educational Resources Information Center

    Ericson, T. J.

    1988-01-01

    Describes an apparatus capable of measuring absolute temperatures of a tungsten filament bulb up to normal running temperature and measuring Botzmann's constant to an accuracy of a few percent. Shows that electrical noise techniques are convenient to demonstrate how the concept of temperature is related to the micro- and macroscopic world. (CW)

  14. Assessment of Sugarcane Yield Potential across Large Numbers of Genotypes Using Canopy Reflectance Measurements

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Canopy reflectance indices have been used to monitor plant growth and estimate yields in many field crops. Little is known if canopy reflectance of sugarcane (a complex hybrid of Saccharum spp.) can be used to estimate growth and yield potential across large numbers of genotypes (clones) in the earl...

  15. Instrument Development Procedures for Silent Reading Measures. Technical Report Number 08-03

    ERIC Educational Resources Information Center

    Liu, Kimy; Sundstrom-Hebert, Krystal; Ketterlin-Geller, Leanne R.; Tindal, Gerald

    2008-01-01

    The purpose of this study was to develop and gather validity evidence for silent reading fluency passages. A number of passages were written following a traditional story grammar structure (character, setting, events) and placed on a computer for students to read silently. We describe in detail, the manner in which content-related evidence was

  16. Measuring Physical Activity with Pedometers in Older Adults with Intellectual Disability: Reactivity and Number of Days

    ERIC Educational Resources Information Center

    Hilgenkamp, Thessa; Van Wijck, Ruud; Evenhuis, Heleen

    2012-01-01

    The minimum number of days of pedometer monitoring needed to estimate valid average weekly step counts and reactivity was investigated for older adults with intellectual disability. Participants (N = 268) with borderline to severe intellectual disability ages 50 years and older were instructed to wear a pedometer for 14 days. The outcome measure…

  17. 76 FR 41859 - Waiver Petition Docket Numbers FRA-2011-0002, CSX Transportation Railroad, and FRA-2004-17565...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-15

    ... Register (75 FR 224) announcing the Union Pacific Railroad's request for an amendment to their existing... Administration (FRA) published a notice in the Federal Register (76 FR 10087) announcing the CSX Transportation... submitted on behalf of an association, business, labor union, etc.). You may review DOT's complete...

  18. Spray washing, absorbent corn starch powder and dry time to reduce bacterial numbers on soiled boiler transport cage flooring

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Most broilers in the U.S. are transported live to slaughter facilities in cages with fiberglass floors. Cages are often used repeatedly without washing and fecal matter deposited on the floor surface can transfer Campylobacter from one flock to another. Drying feces out between uses is an effectiv...

  19. Critical computational aspects of near infrared circular tomographic imaging: Analysis of measurement number, mesh resolution and reconstruction basis

    NASA Astrophysics Data System (ADS)

    Yalavarthy, Phaneendra K.; Dehghani, Hamid; Pogue, Brian W.; Paulsen, Keith D.

    2006-06-01

    The image resolution and contrast in Near-Infrared (NIR) tomographic image reconstruction are affected by parameters such as the number of boundary measurements, the mesh resolution in the forward calculation and the reconstruction basis. Increasing the number of measurements tends to make the sensitivity of the domain more uniform reducing the hypersensitivity at the boundary. Using singular-value decomposition (SVD) and reconstructed images, it is shown that the numbers of 16 or 24 fibers are sufficient for imaging the 2D circular domain for the case of 1% noise in the data. The number of useful singular values increases as the logarithm of the number of measurements. For this 2D reconstruction problem, given a computational limit of 10 sec per iteration, leads to choice of forward mesh with 1785 nodes and reconstruction basis of 30×30 elements. In a three-dimensional (3D) NIR imaging problem, using a single plane of data can provide useful images if the anomaly to be reconstructed is within the measurement plane. However, if the location of the anomaly is not known, 3D data collection strategies are very important. Further the quantitative accuracy of the reconstructed anomaly increased approximately from 15% to 89% as the anomaly is moved from the centre to boundary, respectively. The data supports the exclusion of out of plane measurements may be valid for 3D NIR imaging.

  20. The transport character of quantum state in one-dimensional coupled-cavity arrays: effect of the number of photons and entanglement degree

    NASA Astrophysics Data System (ADS)

    Ma, Shao-Qiang; Zhang, Guo-Feng

    2016-04-01

    The transport properties of the photons injected into one-dimensional coupled-cavity arrays (CCAs) are studied. It is found that the number of photons cannot change the evolution cycle of the system and the time points at which W states and NOON state are obtained with a relatively higher probability. Transport dynamics in the CCAs exhibits that entanglement-enhanced state transmission is more effective phenomenon, and we show that for a quantum state with the maximum concurrence, it can be transmitted completely without considering the case of photon loss.

  1. Atmospheric effects on infrared measurements at ground level: Application to monitoring of transport infrastructures

    NASA Astrophysics Data System (ADS)

    Boucher, Vincent; Dumoulin, Jean

    2014-05-01

    Being able to perform easily non-invasive diagnostics for surveillance and monitoring of critical transport infrastructures is a major preoccupation of many technical offices. Among all the existing electromagnetic methods [1], long term thermal monitoring by uncooled infrared camera [2] is a promising technique due to its dissemination potential according to its low cost on the market. Nevertheless, Knowledge of environmental parameters during measurement in outdoor applications is required to carry out accurate measurement corrections induced by atmospheric effects at ground level. Particularly considering atmospheric effects and measurements in foggy conditions close as possible to those that can be encountered around transport infrastructures, both in visible and infrared spectra. In the present study, atmospheric effects are first addressed by using data base available in literature and modelling. Atmospheric attenuation by particles depends greatly of aerosols density, but when relative humidity increases, water vapor condenses onto the particulates suspended in the atmosphere. This condensed water increases the size of the aerosols and changes their composition and their effective refractive index. The resulting effect of the aerosols on the absorption and scattering of radiation will correspondingly be modified. In a first approach, we used aerosols size distributions derived from Shettle and Fenn [3] for urban area which could match some of experimental conditions encountered during trials on transport infrastructures opened to traffic. In order to calculate the influence of relative humidity on refractive index, the Hänel's model [4] could be used. The change in the particulate size is first related to relative humidity through dry particle radius, particle density and water activity. Once the wet aerosol particle size is found, the effective complex refractive index is the volume weighted average of the refractive indexes of the dry aerosol substance and the water. These changes in refractive indexes lead to the evolution of extinction coefficient Kext according to relative humidity. Using such models in very low visibility conditions leads to the following question: Up to which optical depth (i.e. tau=Kext.d) can we use a simple scattering model as Mie Theory? To show the effect of multiple scattering on previous transmission estimation, Monte-Carlo calculations have been performed. Calculations used a software dedicated to photometrical rendering of fog (PROF [5]). Up to an optical depth tau=1, simple and multiple scatterings differ of less than 2%. For tau >1 the simple scattering model is no more available to keep the error less than 10%. Finally, study of fog effect is proposed. Results obtained by numerical simulations but also by experiments carried out in a dedicated fog tunnel are presented and discussed. Perspectives about possible implementation on on site measurement systems are evocated. REFERENCES [1]Proto M. et al., , 2010. Transport infrastructure surveillance and monitoring by electromagnetic sensing: the ISTIMES project. Sensors, 10,10620-10639, doi: 10.3390/s101210620. [2]J. Dumoulin, A. Crinière, R. Averty ," Detection and thermal characterization of the inner structure of the "Musmeci" bridge deck by infrared thermography monitoring ",Journal of Geophysics and Engineering, Volume 10, Number 2, November 2013, IOP Science, doi:10.1088/1742-2132/10/6/064003. [3]Shettle. P. and Fenn R. W., "Models for the aerosols of the lower atmosphere and the effects of humidity variations on their optical properties", Air Force Geophysics Laboratory 79-0214, (1979). [4]30. Hänel, Gottfried, "The properties of atmospheric aerosol particles as functions of the relarive humidity at thermodynamic equilibrium with the surrounding moist air, in Advances in Geophysics, 73-188. Edited by H.E. Landsberg, and J. Van Mieghem, Academic Press, New York, 1976. [5]31. Dumont E., "Semi-Monte Carlo light tracing applied to the study of road visibility in fog", In Monte Carlo and Quasi-Monte Carlo Methods 1998, Spanier & Niederreiter (Eds.), Springer-Verlag (Pub.), pp.177-187, 1998.

  2. Comparison of correlative measurements of CALIPSO LIDAR and the number 21 EARLINET station (CIEMAT-Madrid)

    NASA Astrophysics Data System (ADS)

    Molero, Francisco; Pujadas, Manuel

    2008-10-01

    CALIPSO is a satellite mission designed to measure the vertical structure and optical properties of aerosol and clouds over the globe. The Science Team for the mission has organized an international program, named quid pro quo (QPQ), to obtain correlative measurements to support validation of its retrieved products. EARLINET, a network of 25 European lidar stations, joined the QPQ program and have been performing correlative measurements at all stations within 80 km from the overpasses ("mandatory" measurements) and additionally at the lidar station which is closest to the actually overpassed site ("suggested" measurements). In this work, we present the results obtained during the primary validation phase for the #21 EARLINET station (CIEMAT-Madrid) correlative measurements. Two different data products have been compared: The "Total Backscatter_Coefficient_532" from level 2 files (released on Jan/2008) and the version 2 (released on Dec/2007) Level 1 data product called "Total_Attenuated_Backscatter_532", that must be compared with a simulated lidar profile calculated from the 532-nm extinction and backscattering coefficients profiles independently measured by the unpolarized elastic channel and Raman channel of the ground system. Several cases with a reasonable agreement in terms of backscattering coefficient magnitude have been found (7 cases, 26% of the total cases analyzed: 27 cases), while cases with bad agreement amounts to 38%. The rest correspond to cases with clouds (18%) and bad assignment of aerosol layer as clouds (18%).

  3. PARALLEL MEASUREMENT AND MODELING OF TRANSPORT IN THE DARHT II BEAMLINE ON ETA II

    SciTech Connect

    Chambers, F W; Raymond, B A; Falabella, S; Lee, B S; Richardson, R A; Weir, J T; Davis, H A; Schultze, M E

    2005-05-31

    To successfully tune the DARHT II transport beamline requires the close coupling of a model of the beam transport and the measurement of the beam observables as the beam conditions and magnet settings are varied. For the ETA II experiment using the DARHT II beamline components this was achieved using the SUICIDE (Simple User Interface Connecting to an Integrated Data Environment) data analysis environment and the FITS (Fully Integrated Transport Simulation) model. The SUICIDE environment has direct access to the experimental beam transport data at acquisition and the FITS predictions of the transport for immediate comparison. The FITS model is coupled into the control system where it can read magnet current settings for real time modeling. We find this integrated coupling is essential for model verification and the successful development of a tuning aid for the efficient convergence on a useable tune. We show the real time comparisons of simulation and experiment and explore the successes and limitations of this close coupled approach.

  4. Electrical Resistivity Measurements of Layer Number Determined Multilayer Graphene Wiring for Future Large Scale Integrated Circuit Interconnects

    NASA Astrophysics Data System (ADS)

    Ito, Kazuyuki; Katagiri, Masayuki; Sakai, Tadashi; Awano, Yuji

    2013-06-01

    To investigate the feasibility of nanocarbon interconnects for future LSIs, the electrical resistance of exfoliated multilayer graphene (MLG) wirings has been studied with accurate measurements of the number of layers. We employed transmission electron microscopy (TEM) as an exact number determination method, atomic force microscopy (AFM) as a simple method, and an extended optical contrast method as an easy distinction method, which we proposed for determining the number of layers. The sheet resistance of MLG wirings, including TEM determined 3-, 54-, and 341-layer MLGs, has been measured using the four-probe method and the layer number dependence of sheet resistance was discussed on the basis of a ladder circuit model simulation. It is shown that the dependence agrees well with the simulations, suggesting parallel conduction in MLG wirings, even if the probe electrodes are deposited just on the top layer of MLG.

  5. Flowfield measurements about a multi-element airfoil at high Reynolds numbers

    NASA Technical Reports Server (NTRS)

    Chin, Vincent D.; Peters, David W.; Spaid, Frank W.; Mcghee, Robert J.

    1993-01-01

    This paper describes experimental data obtained with a multi-element airfoil at flight Reynolds numbers and lift coefficients including Clmax. The wind tunnel test was conducted in the NASA Langley Low Turbulence Pressure Tunnel as part of a cooperative effort between McDonnell Douglas Aerospace and NASA Langley. The airfoil model is a supercritical design configured with a leading-edge slat and a single-segment trailing-edge flap. Data include surface static-pressure distributions (integrated to obtain lift), drag data obtained with wake-rake surveys, and fbwfield surveys obtained with a flat-tube and five-hole probe at nine stations on the configuration's upper surface. Effects of variations in Reynolds number and flap gap on airfoil performance and flowfield survey data are presented.

  6. Review of measured vibration and noise environments experienced by passengers in aircraft and in ground transportation systems

    NASA Technical Reports Server (NTRS)

    Stephens, D. G.

    1975-01-01

    Measured vibration and interior noise data are presented for a number of air and surface vehicles. Consideration is given to the importance of direction effects; of vehicle operations such as take-off, cruise, and landing; and of measurement location on the level and frequency of the measurements. Various physical measurement units or descriptors are used to quantify and compare the data. Results suggest the range of vibration and noise associated with a particular mode of transportation and illustrate the comparative levels in terms of each of the descriptors. Collectively, the results form a data base which may be useful in assessing the ride of existing or future systems relative to vehicles in current operation.

  7. Measurement of effective atomic number and electron density using an EMI scanner.

    PubMed

    Rutherford, R A; Pullan, B R; Isherwood, I

    1976-01-01

    Computed tomography, employing an EMI scanner at two beam energies, can be used to obtain information about the electron density and the effective atomic number of materials. The theory which is discussed has been verified experimentally and then applied in the investigation of some brain tumours in vivo. It is anticipated that, as techniques improve, the ability to carry out chemical and physical analysis of pathological processes in vivo will be an important application of computed tomography. PMID:934468

  8. In situ measurements of particulate number density and size distribution from an aircraft. [using light scattering particle counter

    NASA Technical Reports Server (NTRS)

    Briehl, D.

    1974-01-01

    Two different commercial particulate measuring instruments were flown aboard the NASA Convair 990. A condensation nuclei monitor was utilized to measure particles larger than approximately 0.003 micron in diameter. A specially designed pressurization system was used with this monitor at cabin altitude pressure. A near-forward light scattering counter was used to measure the number and size distribution particles in the size range from 0.5 to 5 microns and greater in diameter. Considerable variation in number density was encountered for both classes of particles at the test altitudes ranging from 5 to 12 km. Presence of clouds could be detected by the light scattering instrument because large numbers of particles would then be registered by the instrument, especially in the size range above 5.0 microns in diameter.

  9. Taking the river inside: Fundamental advances from laboratory experiments in measuring and understanding bedload transport processes

    NASA Astrophysics Data System (ADS)

    Yager, E. M.; Kenworthy, M.; Monsalve, A.

    2015-09-01

    Bedload transport in gravel-bed rivers impacts channel stability, the lifespan of hydraulic structures, physical components of aquatic habitat, and long-term channel evolution. Field measurements of bedload transport are notoriously difficult, which precludes understanding many of the processes and mechanics associated with grain motion. Such uncertainties are exacerbated when using bedload transport equations, most of which were derived using data from a single river or set of laboratory flume experiments. Recently, laboratory experiments have focused on better quantifying the processes that impact bedload fluxes, which can then be used to improve sediment transport predictions. We highlight recent advances in laboratory instrumentation that can be used in bedload transport studies. In particular, more accurate ways to measure bedload fluxes, near-bed turbulence, bed grain sizes, and topography hold great promise. Laboratory experiments have also fundamentally improved our understanding of the influence of sediment supply and armoring processes on bedload fluxes and channel conditions. The importance of flow hydrographs in controlling total bedload transport rates and bedload hysteresis has also been demonstrated using flume experiments. Finally, many details about the mechanics of grain motion including flow turbulence, bed arrangement, and particle transport statistics are only possible through laboratory investigations, and we feature key knowledge gaps that can be improved with further study.

  10. Prescriptions for measuring and transporting local angular momenta in general relativity

    NASA Astrophysics Data System (ADS)

    Flanagan, Éanna É.; Nichols, David A.; Stein, Leo C.; Vines, Justin

    2016-05-01

    For observers in curved spacetimes, elements of the dual space of the set of linearized Poincaré transformations from an observer's tangent space to itself can be naturally interpreted as local linear and angular momenta. We present an operational procedure by which observers can measure such quantities using only information about the spacetime curvature at their location. When applied by observers near spacelike or null infinity in stationary, vacuum, asymptotically flat spacetimes, there is a sense in which the procedure yields the well-defined linear and angular momenta of the spacetime. We also describe a general method by which observers can transport local linear and angular momenta from one point to another, which improves previous prescriptions. This transport is not path independent in general, but becomes path independent for the measured momenta in the same limiting regime. The transport prescription is defined in terms of differential equations, but it can also be interpreted as parallel transport in a particular direct-sum vector bundle. Using the curvature of the connection on this bundle, we compute and discuss the holonomy of the transport law. We anticipate that these measurement and transport definitions may ultimately prove useful for clarifying the physical interpretation of the Bondi-Metzner-Sachs charges of asymptotically flat spacetimes.

  11. Understanding Cosmological Measurements with a large number of mock galaxy catalogues.

    NASA Astrophysics Data System (ADS)

    Manera, M.; Percival, W. J.; Ross, Ashley; Tojeiro, R.; Samushia, L.; Howlett, C.; Vargas-Magaña, M.; Burden, A.; Burden

    2014-05-01

    Mock galaxy catalogues are essential to the error analysis of cosmological measurements from big galaxy surveys covering thousands of square degrees in the sky, like BOSS, WiggleZ, DES, or Euclid. The PTHalos mock galaxy catalogues were used in the BOSS survey to analyse the BAO measurement from the CMASS (z~ 0.57) and LOWZ (z~ 0.32) galaxy samples, which provided the best estimate to date of the cosmic distance scale from galaxy surveys at these redshifts. We review the PTHalos mocks galaxy catalogues and their key contributions to these analyses.

  12. Transportation.

    ERIC Educational Resources Information Center

    Crank, Ron

    This instructional unit is one of 10 developed by students on various energy-related areas that deals specifically with transportation and energy use. Its objective is for the student to be able to discuss the implication of energy usage as it applies to the area of transportation. Some topics covered are efficiencies of various transportation…

  13. Half-life Measurements of Excited Levels in Fission Products around Mass Number 150

    SciTech Connect

    Kojima, Y.; Shima, Y.; Hayashi, H.; Taniguchi, A.; Shibata, M.

    2014-06-15

    A spectrometer to measure nuclear level half-lives has been installed at the on-line isotope separator of the Kyoto University Reactor. This spectrometer consists of a LaBr3 scintillator, a thin plastic scintillator and an HPGe detector. Half-lives are deduced using the β-γ-γ delayed coincidence method. The prompt-time distribution curves measured with the spectrometer give a time resolution (FWHM) of 600 ps for 100-keV γ rays. This resolution means that half-lives down to the subnanosecond range or shorter can be measured. We reported recent measurements of the half-life of {sup 149}Pr and {sup 149}Nd. Some of the more interesting results include the first determination of the half-lives of {sup 149}Pr levels at 86.5 and 125.6 keV, which are 4.2(5) ns and 1.0(2) ns, respectively. In addition, the data indicate that the half-life of the 270.8-keV level in {sup 149}Nd is not 5.1(3) ns as reported previously, but 0.42(3) ns.

  14. Using Measures of Number Sense to Screen for Difficulties in Mathematics: Preliminary Findings

    ERIC Educational Resources Information Center

    Chard, David J.; Clarke, Ben; Baker, Scott; Otterstedt, Janet; Braun, Drew; Katz, Rachell

    2005-01-01

    As recent research efforts have focused on preventing reading difficulties and enhancing the effectiveness of special education services for students with reading problems, similar efforts in mathematics have not been realized. This article describes the development and preliminary field testing of a set of measures designed to screen students in…

  15. Simplified method measures changes in tensile yield strength using least number of specimens

    NASA Technical Reports Server (NTRS)

    Dixon, C. E.

    1967-01-01

    Simplified method determines yield strength due to heat treat, irradiation or mechanical treatment. Each specimen in a group of specimens is tested for yield stress point, subjected to heat treat or irradiation, and retested for new yield stress point which is a measure of change in material.

  16. Cost-Outcome Analysis: Measuring Costs. Evaluation Guides: Guide Number 2.

    ERIC Educational Resources Information Center

    Smith, Jana K.

    The first of two related pamphlets, this guide provides information on how to conduct cost-outcome analyses, with an emphasis on measuring costs. After an introduction that delineates the purpose of the two-part series, the pamphlet is divided into six major sections. The first section, "definitions and rationale," introduces cost-outcome analysis…

  17. Frequency measurements in a finite cylinder wake at a subcritical Reynolds number

    NASA Technical Reports Server (NTRS)

    Budair, M.; Ayoub, A.; Karamcheti, K.

    1991-01-01

    A spectral study of a hot-wire investigation in the near wake of a finite circular cylinder of high-aspect ratio is reported. The measurements included frequency spectra and cross correlations in spanwise and streamwise directions. The study identifies four spanwise regions, in terms of frequency, in the immediate wake of the finite cylinder.

  18. THE DEVELOPMENT OF ACHIEVEMENT MEASURES FOR TRADE AND TECHNICAL EDUCATION. PROGRESS REPORT NUMBER FOUR.

    ERIC Educational Resources Information Center

    BALDWIN, THOMAS S.

    DURING THE FIRST YEAR OF THE PROJECT, TO DISCOVER MORE ADEQUATE WAYS OF MEASURING IMPORTANT TACTILE-KINESTHETIC MODALITIES, APPROXIMATELY 40 INSTRUCTORS WITHIN THE NORTH CAROLINA DEPARTMENT OF COMMUNITY COLLEGES AND TECHNICAL INSTITUTES, WORKING WITH PROJECT STAFF MEMBERS, COMPLETED A CURRICULUM ANALYSIS FOR THE TECHNICAL OR TRADE SPECIALITY IN

  19. A generalized method for measuring weak lensing magnification with weighted number counts

    NASA Astrophysics Data System (ADS)

    Gillis, Bryan R.; Taylor, Andy N.

    2016-03-01

    We present a derivation of a generalized optimally weighted estimator for the weak lensing magnification signal, including a calculation of errors. With this estimator, we present a local method for optimally estimating the local effects of magnification from weak gravitational lensing, using a comparison of number counts in an arbitrary region of space to the expected unmagnified number counts. We show that when equivalent lens and source samples are used, this estimator is simply related to the optimally weighted correlation function estimator used in past work and vice-versa, but this method has the benefits that it can calculate errors with significantly less computational time, that it can handle overlapping lens and source samples, and that it can easily be extended to mass-mapping. We present a proof-of-principle test of this method on data from the Canada-France-Hawaii Telescope Lensing Survey, showing that its calculated magnification signals agree with predictions from model fits to shear data. Finally, we investigate how magnification data can be used to supplement shear data in determining the best-fitting model mass profiles for galaxy dark matter haloes. We find that at redshifts greater than z ˜ 0.6, the inclusion of magnification can often significantly improve the constraints on the components of the mass profile which relate to galaxies' local environments relative to shear alone, and in high-redshift low- and medium-mass bins, it can have a higher signal-to-noise than the shear signal.

  20. Measurement of absolute copy number variation reveals association with essential hypertension

    PubMed Central

    2014-01-01

    Background The role of copy number variation (CNV) has been poorly explored in essential hypertension in part due to technical difficulties in accurately assessing absolute numbers of DNA copies. Droplet digital PCR (ddPCR) provides a powerful new approach to CNV quantitation. The aim of our study was to investigate whether CNVs located in regions previously associated with blood pressure (BP) variation in genome-wide association studies (GWAS) were associated with essential hypertension by the use of ddPCR. Methods Using a “power of extreme” approach, we quantified nucleic acids using ddPCR in white subjects from the Victorian Family Heart Study with extremely high (n = 96) and low (n = 92) SBP, providing power equivalent to 1714 subjects selected at random. Results A deletion of the CNVs esv27061 and esv2757747 on chromosome 1p13.2 was significantly more prevalent in extreme high BP subjects after adjustment for age, body mass index and sex (12.6% vs. 2.2%; P = 0.013). Conclusions Our data suggests that CNVs within regions identified in previous GWAS may play a role in human essential hypertension. PMID:25027169

  1. In vivo measurements of human oral cavity heat and water vapor transport.

    PubMed

    Kaufman, J W; Farahmand, K

    2006-02-28

    Oral heat and water vapor transport may play a significant role in maintaining airway health. This study intended to develop a technique for measuring heat and mass transfer coefficients in the human oral cavity as a function of flow rate. A multi-thermocouple probe was developed which simultaneously measures dry and wet bulb temperatures at two airstream sites while also measuring three buccal wall temperatures. Oral temperature data (airstream and buccal surface) were acquired from eight subjects (two females and six males) breathing at varying flow rates to calculate transport coefficients. Techniques used to validate probe accuracy included correlating experimentally measured heat transfer in a smooth pipe with theoretical plug flow in a circular conduit. Experimental results suggest that modeling the oral cavity as a circular conduit is problematic because Nu measured in a heated pipe differs so greatly from Nu measured in the oral cavity. PMID:15979952

  2. Flow prediction over a transport multi-element high-lift system and comparison with flight measurements

    NASA Technical Reports Server (NTRS)

    Vijgen, P. M. H. W.; Hardin, J. D.; Yip, L. P.

    1992-01-01

    Accurate prediction of surface-pressure distributions, merging boundary-layers, and separated-flow regions over multi-element high-lift airfoils is required to design advanced high-lift systems for efficient subsonic transport aircraft. The availability of detailed measurements of pressure distributions and both averaged and time-dependent boundary-layer flow parameters at flight Reynolds numbers is critical to evaluate computational methods and to model the turbulence structure for closure of the flow equations. Several detailed wind-tunnel measurements at subscale Reynolds numbers were conducted to obtain detailed flow information including the Reynolds-stress component. As part of a subsonic-transport high-lift research program, flight experiments are conducted using the NASA-Langley B737-100 research aircraft to obtain detailed flow characteristics for support of computational and wind-tunnel efforts. Planned flight measurements include pressure distributions at several spanwise locations, boundary-layer transition and separation locations, surface skin friction, as well as boundary-layer profiles and Reynolds stresses in adverse pressure-gradient flow.

  3. Stability and performance characteristics of a fixed arrow wing supersonic transport configuration (SCAT 15F-9898) at Mach numbers from 0.60 to 1.20

    NASA Technical Reports Server (NTRS)

    Decker, J. P.; Jacobs, P. F.

    1978-01-01

    Tests on a 0.015 scale model of a supersonic transport were conducted at Mach numbers from 0.60 to 1.20. Tests of the complete model with three wing planforms, two different leading-edge radii, and various combinations of component parts, including both leading- and trailing-edge flaps, were made over an angle-of-attack range from about -6 deg to 13 deg and at sideslip angles of 0 deg and 2 deg.

  4. Measurements of sediment transport on the sea bed southwest of England

    NASA Astrophysics Data System (ADS)

    Hardisty, J.; Hamilton, D.

    1984-03-01

    Sand transport rates were measured via bedload traps that were inserted into the sediment surface on the continental shelf southwest of England. Analysis of the trapped mobile sediment shows this to be finer and better sorted than nearby Shipek grab samples. The transport rates are combined with simultaneous, near-bed flow measurements to assess a Bagnold type predictive equation,j = k 1(u 2 100 -u 2 100cr)u 100. The measured transport rates vary between 0.41 10-3 and 1.67 10-3 gm/cm s. The data yield a mean calibration coefficient (k 1) of 0.4 10-6 which is slightly lower than values computed from flume and shallow water data.

  5. Lipid Droplets Purified from Drosophila Embryos as an Endogenous Handle for Precise Motor Transport Measurements

    PubMed Central

    Bartsch, Tobias F.; Longoria, Rafael A.; Florin, Ernst-Ludwig; Shubeita, George T.

    2013-01-01

    Molecular motor proteins are responsible for long-range transport of vesicles and organelles. Recent works have elucidated the richness of the transport complex, with multiple teams of similar and dissimilar motors and their cofactors attached to individual cargoes. The interaction among these different proteins, and with the microtubules along which they translocate, results in the intricate patterns of cargo transport observed in cells. High-precision and high-bandwidth measurements are required to capture the dynamics of these interactions, yet the crowdedness in the cell necessitates performing such measurements in vitro. Here, we show that endogenous cargoes, lipid droplets purified from Drosophila embryos, can be used to perform high-precision and high-bandwidth optical trapping experiments to study motor regulation in vitro. Purified droplets have constituents of the endogenous transport complex attached to them and exhibit long-range motility. A novel method to determine the quality of the droplets for high-resolution measurements in an optical trap showed that they compare well with plastic beads in terms of roundness, homogeneity, position sensitivity, and trapping stiffness. Using high-resolution and high-bandwidth position measurements, we demonstrate that we can follow the series of binding and unbinding events that lead to the onset of active transport. PMID:24010661

  6. Measuring Absolute RNA Copy Numbers at High Temporal Resolution Reveals Transcriptome Kinetics In Development

    PubMed Central

    Owens, Nick D. L.; Blitz, Ira L.; Lane, Maura A.; Patrushev, Ilya; Overton, John D.; Gilchrist, Michael J.; Cho, Ken W. Y.; Khokha, Mustafa K.

    2016-01-01

    Summary Transcript regulation is essential for cell function, and misregulation can lead to disease. Despite technologies to survey the transcriptome, we lack a comprehensive understanding of transcript kinetics, which limits quantitative biology. This is an acute challenge in embryonic development where rapid changes in gene expression dictate cell fate decisions. By ultra-high frequency sampling of Xenopus embryos and absolute normalization of sequence reads, we present smooth gene expression trajectories in absolute transcript numbers. During a developmental period approximating the first 8 weeks of human gestation, transcript kinetics vary by 8 orders of magnitude. Ordering genes by expression dynamics, we find temporal synexpression predicts common gene function. Remarkably, a single parameter, the characteristic timescale, can classify transcript kinetics globally and distinguish genes regulating development from those involved in cellular metabolism. Overall, our analysis provides unprecedented insight into the reorganization of maternal and embryonic transcripts and redefines our ability to perform quantitative biology. PMID:26774488

  7. Measurement of atomic number and mass attenuation coefficient in magnesium ferrite

    NASA Astrophysics Data System (ADS)

    Kadam, R. H.; Alone, S. T.; Bichile, G. K.; Jadhav, K. M.

    2007-05-01

    Pure magnesium ferrite sample was prepared by standard ceramic technique and characterized by X-ray diffraction method. XRD pattern revealed that the sample possess single-phase cubic spinel structure. The linear attenuation coefficient (μ), mass attenuation coefficient (μ/ρ), total atomic cross-section (σ_{tot}), total electronic cross-section (σ_{ele}) and the effective atomic number (Z_{eff}) were calculated for pure magnesium ferrite (MgFe_{2}O_{4}). The values of γ-ray mass attenuation coefficient were obtained using a NaI energy selective scintillation counter with radioactive γ-ray sources having energy 0.36, 0.511, 0.662, 1.17 and 1.28 MeV. The experimentally obtained values of μ/ρ and Z_{eff} agreed fairly well with those obtained theoretically.

  8. Measuring Absolute RNA Copy Numbers at High Temporal Resolution Reveals Transcriptome Kinetics in Development.

    PubMed

    Owens, Nick D L; Blitz, Ira L; Lane, Maura A; Patrushev, Ilya; Overton, John D; Gilchrist, Michael J; Cho, Ken W Y; Khokha, Mustafa K

    2016-01-26

    Transcript regulation is essential for cell function, and misregulation can lead to disease. Despite technologies to survey the transcriptome, we lack a comprehensive understanding of transcript kinetics, which limits quantitative biology. This is an acute challenge in embryonic development, where rapid changes in gene expression dictate cell fate decisions. By ultra-high-frequency sampling of Xenopus embryos and absolute normalization of sequence reads, we present smooth gene expression trajectories in absolute transcript numbers. During a developmental period approximating the first 8 weeks of human gestation, transcript kinetics vary by eight orders of magnitude. Ordering genes by expression dynamics, we find that "temporal synexpression" predicts common gene function. Remarkably, a single parameter, the characteristic timescale, can classify transcript kinetics globally and distinguish genes regulating development from those involved in cellular metabolism. Overall, our analysis provides unprecedented insight into the reorganization of maternal and embryonic transcripts and redefines our ability to perform quantitative biology. PMID:26774488

  9. Resonance lamp absorption measurement of OH number density and temperature in expansion tube scramjet engine tests

    NASA Technical Reports Server (NTRS)

    Lempert, Walter R.; Trucco, Richard E.; Bittner, Robert D.

    1992-01-01

    In this paper, we report results of hydroxyl radical and static temperature measurements performed in the General Applied Science Laboratories-NASA HYPULSE expansion tube facility using the microwave resonance lamp absorption technique. Data were obtained as part of a series of hydrogen/air and hydrogen/oxygen combustion tests at stagnation enthalpies corresponding to Mach 17 flight speeds. Data from a representative injector configuration is compared to a full Navier-Stokes CFD solution.

  10. Measuring the Number of M Dwarfs per M Dwarf Using Kepler Eclipsing Binaries

    NASA Astrophysics Data System (ADS)

    Shan, Yutong; Johnson, John A.; Morton, Timothy D.

    2015-11-01

    We measure the binarity of detached M dwarfs in the Kepler field with orbital periods in the range of 1-90 days. Kepler’s photometric precision and nearly continuous monitoring of stellar targets over time baselines ranging from 3 months to 4 years make its detection efficiency for eclipsing binaries nearly complete over this period range and for all radius ratios. Our investigation employs a statistical framework akin to that used for inferring planetary occurrence rates from planetary transits. The obvious simplification is that eclipsing binaries have a vastly improved detection efficiency that is limited chiefly by their geometric probabilities to eclipse. For the M-dwarf sample observed by the Kepler Mission, the fractional incidence of eclipsing binaries implies that there are {0.11}-0.04+0.02 close stellar companions per apparently single M dwarf. Our measured binarity is higher than previous inferences of the occurrence rate of close binaries via radial velocity techniques, at roughly the 2σ level. This study represents the first use of eclipsing binary detections from a high quality transiting planet mission to infer binary statistics. Application of this statistical framework to the eclipsing binaries discovered by future transit surveys will establish better constraints on short-period M+M binary rate, as well as binarity measurements for stars of other spectral types.

  11. Time domain reflectometry measurements of solute transport across a soil layer boundary

    SciTech Connect

    Nissen, H.H.; Moldrup, P.; Kachanoski, R.G.

    2000-02-01

    The mechanisms governing solute transport through layered soil are not fully understood. Solute transport at, above, and beyond the interface between two soil layers during quasi-steady-state soil water movement was investigated using time domain reflectometry (TDR). A 0.26-m sandy loam layer was packed on top of a 1.35-m fine sand layer in a soil column. Soil water content ({theta}) and bulk soil electrical conductivity (EC{sub b}) were measured by 50 horizontal and 2 vertical TDR probes. A new TDR calibration method that gives a detailed relationship between apparent relative dielectric permittivity (K{sub s}) and {theta} was applied. Two replicate solute transport experiments were conducted adding a conservative tracer (CCl) to the surface as a short pulse. The convective lognormal transfer function model (CLT) was fitted to the TDR-measured time integral-normalized resident concentration breakthrough curves (BTCs). The BTCs and the average solute-transport velocities showed preferential flow occurred across the layer boundary. A nonlinear decrease in TDR-measured {theta} in the upper soil toward the soil layer boundary suggests the existence of a 0.10-m zone where water is confined towards fingered flow, creating lateral variations in the area-averaged water flux above the layer boundary. A comparison of the time integral-normalized flux concentration measured by vertical and horizontal TDR probes at the layer boundary also indicates a nonuniform solute transport. The solute dispersivity remained constant in the upper soil layer, but increased nonlinearly (and further down, linearly) with depth in the lower layer, implying convective-dispersive solute transport in the upper soil, a transition zone just below the boundary, and stochastic-convective solute transport in the remaining part of the lower soil.

  12. Improvement of storage, handling, and transportability of fine coal. Quarterly technical progress report number 8, October 1--December 31, 1995

    SciTech Connect

    1996-03-15

    The Mulled Coal process was developed as a means of overcoming the adverse handling characteristics of wet fine coal without thermal drying. The process involves the addition of a low cost, harmless reagent to wet fine coal using off-the-shelf mixing equipment. Based on laboratory- and bench-scale testing, Mulled coal can be stored, shipped, and burned without causing any of the plugging, pasting, carryback and freezing problems normally associated with wet coal. On the other hand, Mulled Coal does not cause the fugitive and airborne dust problems normally associated with thermally dried coal. The objectives of this project are to demonstrate that: the Mulled Coal process, which has been proved to work on a wide range of wet fine coals at bench scale, will work equally well on a continuous basis, producing consistent quality, and at a convincing rate of production in a commercial coal preparation plant; the wet product from a fine coal cleaning circuit can be converted to a solid fuel form for ease of handling and cost savings in storage and rail car transportation; and a wet fine coal product thus converted to a solid fuel form, can be stored, shipped, and burned with conventional fuel handling, transportation, and combustion systems.

  13. Historical Increase in the Number of Factors Measured by Commercial Tests of Cognitive Ability: Are We Overfactoring?

    ERIC Educational Resources Information Center

    Frazier, Thomas W.; Youngstrom, Eric A.

    2007-01-01

    A historical increase in the number of factors purportedly measured by commercial tests of cognitive ability may result from four distinct pressures including: increasingly complex models of intelligence, test publishers' desires to provide clinically useful assessment instruments with greater interpretive value, test publishers' desires to…

  14. 40 CFR Table C-1 to Subpart C of... - Test Concentration Ranges, Number of Measurements Required, and Maximum Discrepancy Specifications

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 5 2011-07-01 2011-07-01 false Test Concentration Ranges, Number of Measurements Required, and Maximum Discrepancy Specifications C Table C-1 to Subpart C of Part 53 Protection of... Reference Methods Pt. 53, Subpt. C, Table C-1 Table C-1 to Subpart C of Part 53—Test Concentration...

  15. 40 CFR Table C-1 to Subpart C of... - Test Concentration Ranges, Number of Measurements Required, and Maximum Discrepancy Specifications

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 6 2012-07-01 2012-07-01 false Test Concentration Ranges, Number of Measurements Required, and Maximum Discrepancy Specifications C Table C-1 to Subpart C of Part 53 Protection of... Reference Methods Pt. 53, Subpt. C, Table C-1 Table C-1 to Subpart C of Part 53—Test Concentration...

  16. 40 CFR Table C-1 to Subpart C of... - Test Concentration Ranges, Number of Measurements Required, and Maximum Discrepancy Specifications

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 6 2014-07-01 2014-07-01 false Test Concentration Ranges, Number of Measurements Required, and Maximum Discrepancy Specifications C Table C-1 to Subpart C of Part 53 Protection of... Reference Methods Pt. 53, Subpt. C, Table C-1 Table C-1 to Subpart C of Part 53—Test Concentration...

  17. 40 CFR Table C-1 to Subpart C of... - Test Concentration Ranges, Number of Measurements Required, and Maximum Discrepancy Specifications

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 6 2013-07-01 2013-07-01 false Test Concentration Ranges, Number of Measurements Required, and Maximum Discrepancy Specifications C Table C-1 to Subpart C of Part 53 Protection of... Reference Methods Pt. 53, Subpt. C, Table C-1 Table C-1 to Subpart C of Part 53—Test Concentration...

  18. An evaluation of the reliability of muscle fiber cross-sectional area and fiber number measurements in rat skeletal muscle

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Background: The reliability of estimating muscle fiber cross-sectional area (measure of muscle fiber size) and fiber number from only a subset of fibers in rat hindlimb muscle cross-sections has not been systematically evaluated. This study examined the variability in mean estimates of fiber cross-s...

  19. Spin transport and precession in graphene measured by nonlocal and three-terminal methods

    SciTech Connect

    Dankert, André Kamalakar, Mutta Venkata; Bergsten, Johan; Dash, Saroj P.

    2014-05-12

    We investigate the spin transport and precession in graphene by using the Hanle effect in nonlocal and three-terminal measurement geometries. Identical spin lifetimes, spin diffusion lengths, and spin polarizations are observed in graphene devices for both techniques over a wide range of temperatures. The magnitude of the spin signals is well explained by spin transport models. These observations rules out any signal enhancements or additional scattering mechanisms at the interfaces for both geometries. This validates the applicability of both the measurement methods for graphene based spintronics devices and their reliable extractions of spin parameters.

  20. Measurement of the transport spin polarization of FeV using point-contact Andreev reflection

    SciTech Connect

    Bailey, William; Osofsky, Mike; Bussman, Konrad; Parker, David S; Cheng, L

    2013-01-01

    The Fe1 xVx alloy system exhibits the lowest known Gilbert relaxation rate of any ferromagnetic metal or binary alloy with G1 435MHz at x1 427% V. Low relaxation rates are of particular interest in modern spin electronic applications involving spin torque. The transport spin polarization of a series of sputtered epitaxial Fe1 xVx samples was measured using point contact Andreev reflection. Values of the transport spin polarization agree well with those measured for pure Fe and are independent of composition. The results indicate that the substitution of up to 50% of V for Fe does not reduce the spin polarization in the alloy.

  1. How to estimate how well people estimate: evaluating measures of individual differences in the approximate number system.

    PubMed

    Chesney, Dana; Bjalkebring, Par; Peters, Ellen

    2015-11-01

    At a glance, one can tell that there are more individual fruits in a pile of 100 apples than in a pile of 20 watermelons, even though the watermelons take up more space. People's ability to distinguish between such nonsymbolic numerical magnitudes without counting is derived from the approximate number system (ANS). Individual differences in this ability (ANS acuity) are emerging as an important predictor in research areas ranging from children's understanding of arithmetic to adults' use of numbers in judgment and decision making. However, ANS acuity must be assessed through proxy tasks that might not show consistent relationships with this ability. Furthermore, practical limitations often confine researchers to using abbreviated measures of this ability, whose reliability is questionable. Here, we developed and tested several novel ANS acuity measures: a nonsymbolic discrimination task designed to account for participants' lapses in attention; three estimation tasks, including one task in which participants estimated the number of dots in a briefly presented set, one in which they estimated the ratio between two sets of dots, and one in which they indicated the correct position of a set of dots on a "number-line" anchored by two sets of dots, as well as a similar number-line task using symbolic numbers. The results indicated that the discrimination task designed to account for lapses in participants' attention holds promise as a reliable measure of ANS acuity, considered in terms of both internal and test-retest reliability. We urge researchers to use acuity measures whose reliability has been demonstrated. PMID:26335207

  2. WIND measurements of proton and alpha particle flow and number density

    NASA Technical Reports Server (NTRS)

    Steinberg, J. T.; Lazarus, A. J.; Ogilvie, J. T.; Lepping, R.; Byrnes, J.; Chornay, D.; Keller, J.; Torbert, R. B.; Bodet, D.; Needell, G. J.

    1995-01-01

    We propose to review measurements of the solar wind proton and alpha particle flow velocities and densities made since launch with the WIND SWE instrument. The SWE Faraday cup ion sensors are designed to be able to determine accurately flow vector directions, and thus can be used to detect proton-alpha particle differential flow. Instances of differential flow, and the solar wind features with which they are associated will be discussed. Additionally, the variability of the percentage of alpha particles as a fraction of the total solar wind ion density will be presented.

  3. Optimum number of technical replicates for the measurement of compression of lamb meat.

    PubMed

    Hoban, J M; van de Ven, R J; Hopkins, D L

    2016-05-01

    Up to six (average 4.63) replicate compression values were collected on cooked m. semimembranosus of lambs that had been raised at six sites across southern Australia (n=1817). Measurements on each sample were made with one of two Lloyd Texture analyser machines, with each machine having a 0.63cm diameter plunger. Based on a log normal model with common variance on the log scale for within sample replicate results, estimates of the within sample variability of compression values were obtained, resulting in a quality control procedure for compression testing based on the coefficient of variation. PMID:26775151

  4. Comparison of Thermoelectric Transport Measurement Techniques Using n-type PbSe

    NASA Astrophysics Data System (ADS)

    Wang, Heng; Fedorov, Mikhail I.; Shabaldin, Aleksander A.; Konstantinov, Piotr P.; Snyder, G. Jeffrey

    2015-06-01

    We compare high-temperature thermoelectric transport measurements at two different institutes using different setups. The material studied is n-type PbSe doped with Cl. The measurements at the Ioffe Institute used a steady-state design which allowed all three properties to be measured simultaneously from bar-shaped samples. Those at Caltech have used Van der Pauw geometry for resistivity, an oscillation method for the Seebeck coefficient, and a laser flash technique for thermal conductivity. The results for each individual property show differences around 10% in some cases, while the evaluation of overall zT for the three samples with different doping levels is mostly below 10%. The steady-state method at the Ioffe Institute was able to measure thermal conductivity at high temperature as accurately as the laser flash method. In general, great caution is needed for any setup in order to accurately measure high-temperature transport properties and hence zT.

  5. Cryogenic wind tunnel technology. A way to measurement at higher Reynolds numbers

    NASA Technical Reports Server (NTRS)

    Beck, J. W.

    1984-01-01

    The goals, design, problems, and value of cryogenic transonic wind tunnels being developed in Europe are discussed. The disadvantages inherent in low-Reynolds-number (Re) wind tunnel simulations of aircraft flight at high Re are reviewed, and the cryogenic tunnel is shown to be the most practical method to achieve high Re. The design proposed for the European Transonic Wind tunnel (ETW) is presented: parameters include cross section. DISPLAY 83A46484/2 = 4 sq m, operating pressure = 5 bar, temperature = 110-120 K, maximum Re = 40 x 10 to the 6th, liquid N2 consumption = 40,000 metric tons/year, and power = 39,5 MW. The smaller Cologne subsonic tunnel being adapted to cryogenic use for preliminary studies is described. Problems of configuration, materials, and liquid N2 evaporation and handling and the research underway to solve them are outlined. The benefits to be gained by the construction of these costly installations are seen more in applied aerodynamics than in basic research in fluid physics. The need for parallel development of both high Re tunnels and computers capable of performing high-Re numerical analysis is stressed.

  6. Measurement of bedload transport in sand-bed rivers: a look at two indirect sampling methods

    USGS Publications Warehouse

    Holmes, Robert R., Jr.

    2010-01-01

    Sand-bed rivers present unique challenges to accurate measurement of the bedload transport rate using the traditional direct sampling methods of direct traps (for example the Helley-Smith bedload sampler). The two major issues are: 1) over sampling of sand transport caused by “mining” of sand due to the flow disturbance induced by the presence of the sampler and 2) clogging of the mesh bag with sand particles reducing the hydraulic efficiency of the sampler. Indirect measurement methods hold promise in that unlike direct methods, no transport-altering flow disturbance near the bed occurs. The bedform velocimetry method utilizes a measure of the bedform geometry and the speed of bedform translation to estimate the bedload transport through mass balance. The bedform velocimetry method is readily applied for the estimation of bedload transport in large sand-bed rivers so long as prominent bedforms are present and the streamflow discharge is steady for long enough to provide sufficient bedform translation between the successive bathymetric data sets. Bedform velocimetry in small sandbed rivers is often problematic due to rapid variation within the hydrograph. The bottom-track bias feature of the acoustic Doppler current profiler (ADCP) has been utilized to accurately estimate the virtual velocities of sand-bed rivers. Coupling measurement of the virtual velocity with an accurate determination of the active depth of the streambed sediment movement is another method to measure bedload transport, which will be termed the “virtual velocity” method. Much research remains to develop methods and determine accuracy of the virtual velocity method in small sand-bed rivers.

  7. Weighted radial dimension: an improved fractal measurement for highway transportation networks distribution

    NASA Astrophysics Data System (ADS)

    Feng, Yongjiu; Liu, Miaolong; Tong, Xiaohua

    2007-06-01

    An improved fractal measurement, the weighted radial dimension, is put forward for highway transportation networks distribution. The radial dimension (DL), originated from subway investigation in Stuttgart, is a fractal measurement for transportation systems under ideal assumption considering all the network lines to be homogeneous curves, ignoring the difference on spatial structure, quality and level, especially the highway networks. Considering these defects of radial dimension, an improved fractal measurement called weighted radial dimension (D WL) is introduced and the transportation system in Guangdong province is studied in detail using this novel method. Weighted radial dimensions are measured and calculated, and the spatial structure, intensity and connectivity of transportation networks are discussed in Guangdong province and the four sub-areas: the Pearl River Delta area, the East Costal area, the West Costal area and the Northern Guangdong area. In Guangdong province, the fractal spatial pattern characteristics of transportation system vary remarkably: it is the highest in the Pearl River Delta area, moderate in Costal area and lowest in the Northern Guangdong area. With the Pearl River Delta area as the centre, the weighted radial dimensions decrease with the distance increasing, while the decline level is smaller in the costal area and greater in the Northern Guangdong province. By analysis of the conic of highway density, it is recognized that the density decrease with the distance increasing from the calculation centre (Guangzhou), demonstrating the same trend as weighted radial dimensions shown. Evidently, the improved fractal measurement, weighted radial dimension, is an indictor describing the characteristics of highway transportation system more effectively and accurately.

  8. Measuring acuity of the approximate number system reliably and validly: the evaluation of an adaptive test procedure

    PubMed Central

    Lindskog, Marcus; Winman, Anders; Juslin, Peter; Poom, Leo

    2013-01-01

    Two studies investigated the reliability and predictive validity of commonly used measures and models of Approximate Number System acuity (ANS). Study 1 investigated reliability by both an empirical approach and a simulation of maximum obtainable reliability under ideal conditions. Results showed that common measures of the Weber fraction (w) are reliable only when using a substantial number of trials, even under ideal conditions. Study 2 compared different purported measures of ANS acuity as for convergent and predictive validity in a within-subjects design and evaluated an adaptive test using the ZEST algorithm. Results showed that the adaptive measure can reduce the number of trials needed to reach acceptable reliability. Only direct tests with non-symbolic numerosity discriminations of stimuli presented simultaneously were related to arithmetic fluency. This correlation remained when controlling for general cognitive ability and perceptual speed. Further, the purported indirect measure of ANS acuity in terms of the Numeric Distance Effect (NDE) was not reliable and showed no sign of predictive validity. The non-symbolic NDE for reaction time was significantly related to direct w estimates in a direction contrary to the expected. Easier stimuli were found to be more reliable, but only harder (7:8 ratio) stimuli contributed to predictive validity. PMID:23964256

  9. Quantum dissipation theory and applications to quantum transport and quantum measurement in mesoscopic systems

    NASA Astrophysics Data System (ADS)

    Cui, Ping

    The thesis comprises two major themes of quantum statistical dynamics. One is the development of quantum dissipation theory (QDT). It covers the establishment of some basic relations of quantum statistical dynamics, the construction of several nonequivalent complete second-order formulations, and the development of exact QDT. Another is related to the applications of quantum statistical dynamics to a variety of research fields. In particular, unconventional but novel theories of the electron transfer in Debye solvents, quantum transport, and quantum measurement are developed on the basis of QDT formulations. The thesis is organized as follows. In Chapter 1, we present some background knowledge in relation to the aforementioned two themes of this thesis. The key quantity in QDT is the reduced density operator rho(t) ≡ trBrho T(t); i.e., the partial trace of the total system and bath composite rhoT(t) over the bath degrees of freedom. QDT governs the evolution of reduced density operator, where the effects of bath are treated in a quantum statistical manner. In principle, the reduced density operator contains all dynamics information of interest. However, the conventional quantum transport theory is formulated in terms of nonequilibrium Green's function. The newly emerging field of quantum measurement in relation to quantum information and quantum computing does exploit a sort of QDT formalism. Besides the background of the relevant theoretical development, some representative experiments on molecular nanojunctions are also briefly discussed. In chapter 2, we outline some basic (including new) relations that highlight several important issues on QDT. The content includes the background of nonequilibrium quantum statistical mechanics, the general description of the total composite Hamiltonian with stochastic system-bath interaction, a novel parameterization scheme for bath correlation functions, a newly developed exact theory of driven Brownian oscillator (DBO) systems, and its closely related solvation mode transformation of system-bath coupling Hamiltonian in general. The exact QDT of DBO systems is also used to clarify the validity of conventional QDT formulations that involve Markovian approximation. In Chapter 3, we develop three nonequivalent but all complete second-order QDT (CS-QDT) formulations. Two of them are of the conventional prescriptions in terms of time-local dissipation and memory kernel, respectively. The third one is called the correlated driving-dissipation equations of motion (CODDE). This novel CS-QDT combines the merits of the former two for its advantages in both the application and numerical implementation aspects. Also highlighted is the importance of correlated driving-dissipation effects on the dynamics of the reduced system. In Chapter 4, we construct an exact QDT formalism via the calculus on path integrals. The new theory aims at the efficient evaluation of non-Markovian dissipation beyond the weak system-bath interaction regime in the presence of time-dependent external field. By adopting exponential-like expansions for bath correlation function, hierarchical equations of motion formalism and continued fraction Liouville-space Green's function formalism are established. The latter will soon be used together with the Dyson equation technique for an efficient evaluation of non-perturbative reduced density matrix dynamics. The interplay between system-bath interaction strength, non-Markovian property, and the required level of hierarchy is also studied with the aid of simple spin-boson systems, together with the three proposed schemes to truncate the infinite hierarchy. In Chapter 5, we develop a nonperturbative theory of electron transfer (ET) in Debye solvents. The resulting exact and analytical rate expression is constructed on the basis of the aforementioned continued fraction Liouville-space Green's function formalism, together with the Dyson equation technique. Not only does it recover the celebrated Marcus' inversion and Kramers' turnover behaviors, the new theory also shows some distinct quantum solvation effects that can alter the ET mechanism. Moreover, the present theory predicts further for the ET reaction thermodynamics, such as equilibrium Gibbs free-energy and entropy, some interesting solvent-dependent features that are calling for experimental verification. In Chapter 6, we discuss the constructed QDTs, in terms of their unified mathematical structure that supports a linear dynamics space, and thus facilitates their applications to various physical problems. The involving details are exemplified with the CODDE form of QDT. As the linear space is concerned, we identify the Schrodinger versus Heisenberg picture and the forward versus backward propagation of the reduced, dissipative Liouville dynamics. For applications we discuss the reduced linear response theory and the optimal control problems, in which the correlated effects of non-Markovian dissipation and field driving are shown to be important. In Chapter 7, we turn to quantum transport, i.e., electric current through molecular or mesoscopic systems under finite applied voltage. By viewing the nonequilibrium transport setup as a quantum open system, we develop a reduced-density-matrix approach to quantum transport. The resulting current is explicitly expressed in terms of the molecular reduced density matrix by tracing out the degrees of freedom of the electrodes at finite bias and temperature. We propose a conditional quantum master equation theory, which is an extension of the conventional (or unconditional) QDT by tracing out the well-defined bath subsets individually, instead of the entire bath degrees of freedom. Both the current and the noise spectrum can be conveniently analyzed in terms of the conditional reduced density matrix dynamics. By far, the QDT (including the conditional one) has only been exploited in second-order form. A self-consistent Born approximation for the system-electrode coupling is further proposed to recover all existing nonlinear current-voltage behaviors including the nonequilibrium Kondo effect. Transport theory based on the exact QDT formalism will be developed in future. In Chapter 8, we study the quantum measurement of a qubit with a quantum-point-contact detector. On the basis of a unified quantum master equation (a form of QDT), we study the measurement-induced relaxation and dephasing of the qubit. Our treatment pays particular attention on the detailed-balance relation, which is a consequence of properly accounting for the energy exchange between the qubit and detector during the measurement process. We also derive a conditional quantum master equation for quantum measurement in general, and study the readout characteristics of the qubit measurement. Our theory is applicable to the quantum measurement at arbitrary voltage and temperature. A number of remarkable new features are found and highlighted in concern with their possible relevance to future experiments. In Chapter 9, we discuss the further development of QDT, aiming at an efficient evaluation of many-electron systems. This will be carried out by reducing the many-particle (Fermion or Boson) QDT to a single-particle one by exploring, e.g. the Wick's contraction theorem. It also results in a time-dependent density functional theory (TDDFT) for transport through complex large-scale (e.g. molecules) systems. Primary results of the TDDFT-QDT are reported. In Chapter 10, we summary the thesis, and comment and remark on the future work on both the theoretical and application aspects of QDT.

  10. Suspended solids transport: an analysis based on turbidity measurements and event based fully calibrated hydrodynamic models.

    PubMed

    Langeveld, J G; Veldkamp, R G; Clemens, F

    2005-01-01

    Modelling suspended solids transport is a key issue for predicting the pollution load discharged by CSOs. Nonetheless, there is still much debate on the main drivers for suspended solids transport and on the modelling approach to be adopted. Current sewer models provide suspended solids transport models. These models, however, rely upon erosion-deposition criteria developed in fluvial environments, therewith oversimplifying the sewer sediment characteristics. Consequently, the performance of these models is poor from a theoretical point of view. To get an improved understanding of the temporal and spatial variations in suspended solids transport, a measuring network was installed in the sewer system of Loenen in conjunction with a hydraulic measuring network from June through December 2001. During the measuring period, 15 storm events rendered high-quality data on both the hydraulics and the turbidity. For each storm event, a hydrodynamic model was calibrated using the Clemens' method. The conclusion of the paper is that modelling of suspended solids transport has been and will be one of the challenges in the field of urban drainage modelling. A direct relation of either shear stress or flow velocity with turbidity could not be found, likely because of the time varying characteristics of the suspended solids. PMID:16206848

  11. Investigating fluctuations that influence transport with heavy ion beam probe measurements in the MST RFP

    NASA Astrophysics Data System (ADS)

    Fimognari, P. J.; Demers, D. R.

    2013-10-01

    Drift-wave-like modes are an important instability impacting transport in confined toroidal plasmas. They are the major driver in the tokamak and also likely govern it in optimized stellarators and select RFP regimes. The HIBP can characterize this turbulence and related phenomena by measuring fluctuations of density and potential in the plasma interior. It helps quantify amplitudes, wavelengths, cross phases, and other characteristics necessary for validation of gyrokinetic codes. The unique ability of the HIBP to acquire these quantities from the plasma core, in multiple magnetic configurations, will advance understanding of transport. Properties of low and high confinement regimes in many magnetic configurations, including the RFP, differ. Transport in standard confinement RFP plasmas is governed by magnetic fluctuations arising from tearing instabilities; these fluctuations are reduced with current profile control and the residual transport is likely electrostatic. An HIBP on MST is measuring radial profiles of fluctuations (up to 500 kHz) in the plasma interior. Temperature and density gradients in these plasmas are strongest in the region r/a ~ 0.5-0.8, accessible to the HIBP. These measurements, made with the first and only HIBP operating on an RFP, will shed light on dynamics influencing transport. Work supported by US DoE.

  12. Measurement of a number of indices of hand and movement angles in pianists with overuse disorders.

    PubMed

    Sakai, N; Shimawaki, S

    2010-07-01

    Abduction angles of the thumb and little finger, hand span, length of thumb, middle finger and little finger were measured using radiographs of the right hand with the thumb and the little finger abducted, in a comparative study of 220 pianists with overuse disorder and 62 unaffected pianists. Overuse disorders included tenosynovitis, lateral and medial epicondylitis, forearm flexor muscle pain, distal tendinitis of the wrist extensors and flexors and intrinsic muscle pain. Hand span or other hand size parameters showed significant differences, while abduction angles showed no difference. The patients' group had smaller hand size than the controls when analyzed for tenosynovitis, epicondylitis and muscle pain. From these results we hypothesize that pianists with small hands tend to hyper-abduct and hyper-extend the thumb to attain greater hand span. Their little finger is also stiffer and the hypothenar muscle and the wrist flexors need greater strength to resist the reaction force in each piano key. PMID:20427408

  13. New gauge fields from extension of space time parallel transport of vector spaces to the underlying number systems.

    SciTech Connect

    Benioff, P.

    2011-06-01

    One way of describing gauge theories in physics is to assign a vector space {bar V}{sub x} to each space time point x. For each x the field {psi} takes values {psi}(x) in {bar V}{sub x}. The freedom to choose a basis in each {bar V}{sub x} introduces gauge group operators and their Lie algebra representations to define parallel transformations between vector spaces. This paper is an exploration of the extension of these ideas to include the underlying scalar complex number fields. Here a Hilbert space, {bar H}{sub x}, as an example of {bar V}{sub x}, and a complex number field, {bar C}{sub x}, are associated with each space time point. The freedom to choose a basis in {bar H}{sub x} is expanded to include the freedom to choose complex number fields. This expansion is based on the discovery that there exist representations of complex (and other) number systems that differ by arbitrary scale factors. Compensating changes must be made in the basic field operations so that the relevant axioms are satisfied. This results in the presence of a new real valued gauge field A(x). Inclusion of A(x) into covariant derivatives in Lagrangians results in the description of A(x) as a gauge boson for which mass is optional. The great accuracy of QED suggests that the coupling constant of A(x) to matter fields is very small compared to the fine structure constant. Other physical properties of A(x) are not known at present.

  14. Measuring and modelling the local-scale spatio-temporal variation of urban particle number size distributions and black carbon

    NASA Astrophysics Data System (ADS)

    Ruths, Matthias; von Bismarck-Osten, Clemens; Weber, Stephan

    2014-10-01

    Mobile measurements were performed to study the spatio-temporal variation of particle number size distributions (NSD) in the range 11 < Dp < 365 nm as well as total particle number and black carbon concentrations in Braunschweig, Germany during the winter and summer period 2012/2013. The study area of about 1 km2 consisted of six different outdoor microenvironments (ME) that were classified according to different traffic intensities and dominant land use types along the measurement route. Highest averaged total number concentrations measured at roadside (RO) were 2.5 × 104 pt cm-3 (with a maximum of 7.6 × 104 pt cm-3) during winter and about 1.2 × 104 pt cm-3 on average during the summer campaign. Measurement spots which are more distant to traffic were characterised by lower concentrations of 1.6 × 104 pt cm-3 and 9.0 × 103 pt cm-3 during winter and summer, respectively. Black carbon (BC) concentrations were also clearly related to traffic emissions and resulted in concentrations of 2.8 μg m-3 on average (absolute maximum of 6.2 μg m-3) at RO-sites. The concentrations of particles and BC in the different ME (aggregated from the single measurement spots) documented the concentration of both metrics to be a function of distance of the measurement to fresh traffic emissions. A multiple regression based model was established to identify significant parameters which can be used to model the microscale variation of particle NSD in the outdoor ME. Two models with different numbers of input parameters were calculated. The first contained all measured parameters as input, the second only a reduced number consisting of TNC, BC and wind speed. Both models worked convincingly, even the approach with the limited number of input parameters. The average size integrated (TNC) deviation to observed data in all ME during both seasons was <13%. The best agreement between model and observations is given for the near-traffic ME.

  15. A method for measuring gene copy number in biological samples without using control samples of known copies.

    PubMed

    Ji, Wan; Li, Jian; Liu, Jinfeng

    2012-01-01

    Various human diseases are caused by gene copy number variants, underlining the importance of determining disease gene copy number for clinical diagnostics. In this study, we describe a method for determining gene copy number in a biological organism. In this method, both a target gene and an internal control gene were amplified from the organism by regular PCR. The PCR products were purified and quantified, and the target and internal control genes were mixed at different molar ratios. Real-time PCR was then used to measure the quantification cycle (Cq) values of both the target and internal control genes in the mixtures. A standard curve was constructed to correlate the differences between the Cq values and the logarithmic ratios of the target gene to the internal control gene. Real-time PCR was then used to measure the Cq values of both the target and internal control genes in experimental samples; the copy number of the target gene in the sample can be calculated readily from the calculated standard curve. This method was validated by a set of internal control genes and a foreign gene in transgenic alfalfa, demonstrating the utility of this method in the determination of gene copy number for various applications. PMID:22449696

  16. Phase Averaged Measurements of the Coherent Structure of a Mach Number 0.6 Jet. M.S. Thesis

    NASA Technical Reports Server (NTRS)

    Emami, S.

    1983-01-01

    The existence of a large scale structure in a Mach number 0.6, axisymmetric jet of cold air was proven. In order to further characterize the coherent structure, phase averaged measurements of the axial mass velocity, radial velocity, and the product of the two were made. These measurements yield information about the percent of the total fluctuations contained in the coherent structure. These measured values were compared to the total fluctuation levels for each quantity and the result expressed as a percent of the total fluctuation level contained in the organized structure at a given frequency. These measurements were performed for five frequencies (St=0.16, 0.32, 0.474, 0.95, and 1.26). All of the phase averaged measurements required that the jet be artificially excited.

  17. Bipolar carrier transport in tris(8-hydroxy-quinolinato) aluminum observed by impedance spectroscopy measurements

    NASA Astrophysics Data System (ADS)

    Ishihara, Shingo; Hase, Hiroyuki; Okachi, Takayuki; Naito, Hiroyoshi

    2011-08-01

    We studied bipolar carrier transport in tris(8-hydroxy-quinolinato) aluminum (Alq3) thin films using impedance spectroscopy (IS). Two transit times were observed in the impedance spectra of the Alq3 double-injection diodes. The mobilities determined from the transit times are in good agreement with the electron and the hole mobilities in Alq3 measured by IS using single injection diodes and by the time-of-flight transient photocurrent technique. The bipolar carrier transport observed in Alq3 shows that the carrier recombination of Alq3 is weak on the basis of the simulation [M. Schmeits, J. Appl. Phys. 101, 084508 (2007)]. Simultaneous measurements of electron and hole mobilities are useful in the study of charge-carrier transport in active layers in organic light-emitting diodes and organic solar cells.

  18. Effect of using a cowl when measuring the fiber number concentration by the membrane filter method.

    PubMed

    Kauffer, Edmond; Eypert-Blaison, Céline

    2004-05-01

    This article compares samples taken with three different sampling heads: (1). open-faced sampling head, (2). open-faced sampling head with stainless-steel extension cowl, and (3). open-faced sampling head with graphite-impregnated extension cowl. Sampling was performed in three factories producing man-made mineral fibers (alkaline silicate fibers, refractory ceramic fibers, glass fibers). Flow rate was varied (1 L/min or 2 L/min). The average densities measured on the sampling filter for fibers of <3 microm in diameter varied from 19 to 91 fibers/mm(2). No significant difference in fiber density was observed in relation to the nature of the sampling head for fibers with a diameter of <3 microm. The deposits noted on the internal walls of the cowl were small and much less than that documented in the literature for man-made mineral fibers until now. They were greater for fibers with a diameter of >3 microm than for those with a diameter of <3 microm. For large-diameter fibers, it would appear that cowl deposit can be reduced by increasing the sampling flow rate. PMID:15238337

  19. Hybrid PIV-Particle Tracking Technique Applied to High Reynolds Number Turbulent Boundary Layer Measurements

    NASA Astrophysics Data System (ADS)

    Soria, Julio; Atkinson, Callum; Buchmann, Nicolas

    2014-11-01

    Zero-pressure gradient turbulent boundary layer (ZPGTBL) experiments in both the LTRAC water tunnel (LTRAC-WT) at Monash University and the University of Melbourne HRNTBL wind tunnel were undertaken up to Reτ = 20 , 000 . Both experiments represent the flow along the centreline of each test section in the streamwise - wall-normal plane. Two PCO Dimax cameras with 2008 × 2008 pixel arrays were used in conjunction with a high-repetition laser to measure the time-resolved 2C-2D velocity field in the LTRAC-WT. The HRNTBL wind tunnel experiments employed nine PCO pro.4000 cameras each with a 4008 × 2672 pixel array. Two double cavity pulsed Nd:YAG lasers were used to acquire single-exposed PIV images simultaneously on all cameras to yield high spatial resolution 2C-2D velocity fields over a large extend of the ZPGTBL. In both cases, the single-exposed PIV images were analysed using multigrid cross-correlation PIV analysis, which has been enhanced to include a hybrid velocimetry step in which the PIV velocity is used as an estimator to a subsequent particle tracking refinement step. Statistics of the ZPGTBL velocity field as well as the high spatial resolution instantaneous structure and spatio-temporal structure of the ZPGTBL will be presented. The support of the Australian Research Council via Discovery and LIEF grants is gratefully acknowledged.

  20. High-Reynolds Number Active Blowing Semi-Span Force Measurement System Development

    NASA Technical Reports Server (NTRS)

    Lynn, Keith C.; Rhew, Ray D.; Acheson, Michael J.; Jones, Gregory S.; Milholen, William E.; Goodliff, Scott L.

    2012-01-01

    Recent wind-tunnel tests at the NASA Langley Research Center National Transonic Facility utilized high-pressure bellows to route air to the model for evaluating aircraft circulation control. The introduction of these bellows within the Sidewall Model Support System significantly impacted the performance of the external sidewall mounted semi-span balance. As a result of this impact on the semi-span balance measurement performance, it became apparent that a new capability needed to be built into the National Transonic Facility s infrastructure to allow for performing pressure tare calibrations on the balance in order to properly characterize its performance under the influence of static bellows pressure tare loads and bellows thermal effects. The objective of this study was to design both mechanical calibration hardware and an experimental calibration design that can be employed at the facility in order to efficiently and precisely perform the necessary loadings in order to characterize the semi-span balance under the influence of multiple calibration factors (balance forces/moments and bellows pressure/temperature). Using statistical design of experiments, an experimental design was developed allowing for strategically characterizing the behavior of the semi-span balance for use in circulation control and propulsion-type flow control testing at the National Transonic Facility.

  1. Measurements and implications of particle and momentum transport from magnetic stochasticity in MST

    NASA Astrophysics Data System (ADS)

    Ding, Weixing

    2007-11-01

    Magnetic stochasticity associated with radial magnetic field fluctuations (δbr) is expected to have significant effects on plasma transport. Particle and momentum transport due to stochastic magnetic fields are defined as <δj//,e δbr>eB0 and <δp//,i δbr>B0, respectively, where δj//,e and δp//,i are parallel electron current density fluctuations and parallel ion pressure fluctuations. A recently developed differential interferometer method is used to measure local density fluctuations, while a fast Faraday rotation diagnostic measures radial magnetic field fluctuations and current density fluctuations. Direct measurements of particle and momentum transport during reconnection events (the crash phase of a sawtooth oscillation) in the MST reversed field pinch show that; (1) the magnetic fluctuation-induced particle flux accounts for the change in the core equilibrium density, and (2) the convective component of the momentum transport from stochasticity is of sufficient magnitude to contribute to the known anomalous momentum transport in the plasma core. Furthermore, the difference between magnetic fluctuation-induced electron flux and ion flux, (<δj// δbr>eB0), has been experimentally determined by measuring Maxwell stress directly in the plasma core. It is nonzero (transport is locally nonambipolar) and produces a large radial electric field (and field shear) localized to the reconnection (resonant) surface. This electric field implies the existence of a localized zonal flow that reverses direction about a reconnection surface -- a new mechanism for zonal flow generation. Author acknowledges contributions from D.L. Brower, B.H. Deng, T.F. Yates, UCLA, and the MST team. Work is supported by DoE and NSF.

  2. Do we really need a large number of particles to simulate bimolecular reactive transport with random walk methods? A kernel density estimation approach

    NASA Astrophysics Data System (ADS)

    Rahbaralam, Maryam; Fernàndez-Garcia, Daniel; Sanchez-Vila, Xavier

    2015-12-01

    Random walk particle tracking methods are a computationally efficient family of methods to solve reactive transport problems. While the number of particles in most realistic applications is in the order of 106-109, the number of reactive molecules even in diluted systems might be in the order of fractions of the Avogadro number. Thus, each particle actually represents a group of potentially reactive molecules. The use of a low number of particles may result not only in loss of accuracy, but also may lead to an improper reproduction of the mixing process, limited by diffusion. Recent works have used this effect as a proxy to model incomplete mixing in porous media. In this work, we propose using a Kernel Density Estimation (KDE) of the concentrations that allows getting the expected results for a well-mixed solution with a limited number of particles. The idea consists of treating each particle as a sample drawn from the pool of molecules that it represents; this way, the actual location of a tracked particle is seen as a sample drawn from the density function of the location of molecules represented by that given particle, rigorously represented by a kernel density function. The probability of reaction can be obtained by combining the kernels associated to two potentially reactive particles. We demonstrate that the observed deviation in the reaction vs time curves in numerical experiments reported in the literature could be attributed to the statistical method used to reconstruct concentrations (fixed particle support) from discrete particle distributions, and not to the occurrence of true incomplete mixing. We further explore the evolution of the kernel size with time, linking it to the diffusion process. Our results show that KDEs are powerful tools to improve computational efficiency and robustness in reactive transport simulations, and indicates that incomplete mixing in diluted systems should be modeled based on alternative mechanistic models and not on a limited number of particles.

  3. Measurements of Combined Axial Mass and Heat Transport in He II.

    ERIC Educational Resources Information Center

    Johnson, Warren W.; Jones, Michael C.

    An experiment was performed that allowed measurements of both axial mass and heat transport of He-II (the superfluid phase of helium 4) in a long tube. The apparatus allowed the pressure difference and the temperature difference across the flow tube to each be independently adjusted, and the resulting steady-state values of net fluid velocity and…

  4. DIRECT MEASUREMENT OF FAST AXONAL ORGANELLE TRANSPORT IN THE SCIATIC NERVE OF RATS TREATED WITH ACRYLAMIDE

    EPA Science Inventory

    The effects of acrylamide on fast axonal transport have been measured primarily using the indirect methods of isotope or enzyme accumulation. e report the first direct evaluation of the effects of sub-chronic acrylamide dosing (150, 300 or 500 mg/kg total dose) on the fast axonal...

  5. Laser Transit-Time Measurements between the Earth and the Moon with a Transportable System.

    PubMed

    Lehr, C G; Criswell, S J; Ouellette, J P; Sozanski, P W; Mulholland, J D; Shelus, P J

    1973-06-01

    A high-radiance, pulsed laser system with a transportable transmitting unit was used at Agassiz Station, Harvard College Observatory, Harvard, Massachusetts, to measure the transit times of 25-nanosecond, 10-joule, 530-nanometer pulses from the earth to the Apollo 15 retroreflector on the moon and back. PMID:17735924

  6. PROJECT MISTT (MIDWEST INTERSTATE SULFUR TRANSFORMATION AND TRANSPORT): MEASUREMENTS AND DATA BASE

    EPA Science Inventory

    Project MISTT (Midwest Interstate Sulfur Transformation and Transport) was an EPA-sponsored research program of field measurements and data analyses carried out in the mid-seventies in the St. Louis region. The objective was to investigate quantitatively the dynamics and kinetics...

  7. 41 CFR 102-117.270 - What are agency performance measures for transportation?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 41 Public Contracts and Property Management 3 2010-07-01 2010-07-01 false What are agency performance measures for transportation? 102-117.270 Section 102-117.270 Public Contracts and Property Management Federal Property Management Regulations System (Continued) FEDERAL MANAGEMENT...

  8. On the Dielectric Constant for Acetanilide: Experimental Measurements and Effect on Energy Transport

    NASA Astrophysics Data System (ADS)

    Careri, G.; Compatangelo, E.; Christiansen, P. L.; Halding, J.; Skovgaard, O.

    1987-01-01

    Experimental measurements of the dielectric constant for crystalline acetanilide powder for temperatures ranging from - 140°C to 20°C and for different hydration levels are presented. A Davydov-soliton computer model predicts dramatic changes in the energy transport and storage for typically increased values of the dielectric constant.

  9. Determination of car on-road black carbon and particle number emission factors and comparison between mobile and stationary measurements

    NASA Astrophysics Data System (ADS)

    Ježek, I.; Drinovec, L.; Ferrero, L.; Carriero, M.; Močnik, G.

    2015-01-01

    We have used two methods for measuring emission factors (EFs) in real driving conditions on five cars in a controlled environment: the stationary method, where the investigated vehicle drives by the stationary measurement platform and the composition of the plume is measured, and the chasing method, where a mobile measurement platform drives behind the investigated vehicle. We measured EFs of black carbon and particle number concentration. The stationary method was tested for repeatability at different speeds and on a slope. The chasing method was tested on a test track and compared to the portable emission measurement system. We further developed the data processing algorithm for both methods, trying to improve consistency, determine the plume duration, limit the background influence and facilitate automatic processing of measurements. The comparison of emission factors determined by the two methods showed good agreement. EFs of a single car measured with either method have a specific distribution with a characteristic value and a long tail of super emissions. Measuring EFs at different speeds or slopes did not significantly influence the EFs of different cars; hence, we propose a new description of vehicle emissions that is not related to kinematic or engine parameters, and we rather describe the vehicle EF with a characteristic value and a super emission tail.

  10. Determination of car on-road black carbon and particle number emission factors and comparison between mobile and stationary measurements

    NASA Astrophysics Data System (ADS)

    Ježek, I.; Drinovec, L.; Ferrero, L.; Carriero, M.; Močnik, G.

    2014-06-01

    We have used two methods for measuring emission factors (EF) in real driving conditions on five cars in a controlled environment: the stationary method, where the investigated vehicle drives by the stationary measurement platform and the composition of the plume is measured; and the chasing method, where a mobile measurement platform drives behind the investigated vehicle. We measured EF of black carbon and particle number concentration. The stationary method was tested for repeatability at different speeds and on a slope. The chasing method was tested on a test track and compared to the portable emission measurement system. We further developed the data processing algorithm for both methods, trying to improve consistency, determine the plume duration, limit the background influence and facilitate automatic processing of measurements. The comparison of emission factors determined by the two methods showed good agreement. EFs of a single car measured with either method have a specific distribution with a characteristic value and a long tail of super emissions. Measuring EFs at different speeds or slopes did not significantly influence the EFs of different cars, hence we propose a new description of vehicle emissions that is not related to kinematic or engine parameters, rather we describe the vehicle EF with a characteristic value and a "super emission" tail.

  11. Development of a scanning tunneling potentiometry system for measurement of electronic transport at short length scales

    NASA Astrophysics Data System (ADS)

    Rozler, Michael

    It is clear that complete understanding of macroscopic properties of materials is impossible without a thorough knowledge of behavior at the smallest length scales. While the past 25 years have witnessed major advances in a variety of techniques that probe the nanoscale properties of matter, electrical transport measurements -- the heart of condensed matter research -- have lagged behind, never progressing beyond bulk measurements. This thesis describes a scanning tunneling potentiometry (STP) system developed to simultaneously map the transport-related electrochemical potential distribution of a biased sample along with its surface topography, extending electronic transport measurements to the nanoscale. Combining a novel sample biasing technique with a continuous current-nulling feedback scheme pushes the noise performance of the measurement to its fundamental limit - the Johnson noise of the STM tunnel junction. The resulting 130 nV voltage sensitivity allows us to spatially resolve local potentials at scales down to 2 nm, while maintaining atomic scale STM imaging, all at scan sizes of up to 15 microns. A mm-range two-dimensional coarse positioning stage and the ability to operate from liquid helium to room temperature with a fast turn-around time greatly expand the versatility of the instrument. Use of carefully selected model materials, combined with excellent topographic and voltage resolution has allowed us to distinguish measurement artifacts caused by surface roughness from true potentiometric features, a major problem in previous STP measurements. The measurements demonstrate that STP can produce physically meaningful results for homogeneous transport as well as non-uniform conduction dominated by material microstructures. Measurements of several physically interesting materials systems are presented as well, revealing new behaviors at the smallest length sales. The results establish scanning tunneling potentiometry as a useful tool for physics and materials science.

  12. Statistical Measurements of Contact Conditions of 478 Transport-airplane Landings During Routine Daytime Operations

    NASA Technical Reports Server (NTRS)

    Silsby, Norman S

    1955-01-01

    Statistical measurements of contact conditions have been obtained, by means of a special photographic technique, of 478 landings of present-day transport airplanes made during routine daylight operations in clear air at the Washington National Airport. From the measurements, sinking speeds, rolling velocities, bank angles, and horizontal speeds at the instant before contact have been evaluated and a limited statistical analysis of the results has been made and is reported in this report.

  13. Development of high speed continuous transport critical current measurement system for long piece of HTS conductor

    NASA Astrophysics Data System (ADS)

    Kim, Seokho; Park, Minwon; Yu, In-Keun; Kim, Gyeong-Hun; Ha, Hong-Su; Sim, Kideok; Oh, Sang-Soo; Moon, Seung-Hyun

    2013-01-01

    In case of long pieces of HTS conductor, their critical current measurement is an important process for the conductor manufacturer and the customer, however, it is very time consuming process. Conventional critical current measurement is carried out by ‘four probe method’, which increase the transport current and measure the voltage between the fixed voltage taps. Therefore, it consists of conductor moving and measuring process. To speed up the measuring process, longer distance between voltage taps is required. In this case, the measured critical current is averaged and small defects, which can be very crucial for thermal stability, cannot be found. Therefore, the limitation of the voltage tap length should be carefully decided considering the cooling environment. Another non-contact or indirect method is to measure the screening effect of magnetic field and converting the field signal to the critical current, which is called as hall probe method. This process is known as a very efficient way to find local defects and estimate the distribution of the critical current, however, it contains inevitable error and noise because it should measure the small magnetic field signals. This paper describes a new critical current measurement system, which have similar hardware structure of conventional ‘four probe method’. However, it is much faster than other systems using fast feedback control of the transport current while the conductor is continuously moving with high speed. The measured results are compared with the conventional method and hall probe method.

  14. Sea level variation as an indicator of Florida current volume transport: comparisons with direct measurements.

    PubMed

    Maul, G A; Chew, F; Bushnell, M; Mayer, D A

    1985-01-18

    Sea level measurements from tide gauges at Miami, Florida, and Cat Cay, Bahamas, and bottom pressure measurements from a water depth of 50 meters off Jupiter, Florida, and a water depth of 10 meters off Memory Rock, Bahamas, were correlated with 81 concurrent direct volume transport observations in the Straits of Florida. Daily-averaged sea level from either gauge on the Bahamian side of the Straits was poorly correlated with transport. Bottom pressure off Jupiter had a linear coefficient of determination ofr(2) = 0.93, and Miami sea level, when adjusted for weather effects, had r(2) = 0.74; the standard errors of estimating transports were +/- 1.2 x 10(6) and +/- 1.9 x 10(6) cubic meters per second, respectively. A linear multivariate regression, which combined bottom pressure, weather, and the submarine cable observations between Jupiter and the Bahamas, had r(2) = 0.94 with a standard error of estimating transport of +/- 1.1 x 10(6) cubic meters per second. These results suggest that a combination of easily obtained observations is sufficient to adequatelv monitor the daily volume transport fluctuations of the Florida Current. PMID:17742102

  15. Lost in transportation: Information measures and cognitive limits in multilayer navigation

    PubMed Central

    Gallotti, Riccardo; Porter, Mason A.; Barthelemy, Marc

    2016-01-01

    Cities and their transportation systems become increasingly complex and multimodal as they grow, and it is natural to wonder whether it is possible to quantitatively characterize our difficulty navigating in them and whether such navigation exceeds our cognitive limits. A transition between different search strategies for navigating in metropolitan maps has been observed for large, complex metropolitan networks. This evidence suggests the existence of a limit associated with cognitive overload and caused by a large amount of information that needs to be processed. In this light, we analyzed the world’s 15 largest metropolitan networks and estimated the information limit for determining a trip in a transportation system to be on the order of 8 bits. Similar to the “Dunbar number,” which represents a limit to the size of an individual’s friendship circle, our cognitive limit suggests that maps should not consist of more than 250 connection points to be easily readable. We also show that including connections with other transportation modes dramatically increases the information needed to navigate in multilayer transportation networks. In large cities such as New York, Paris, and Tokyo, more than 80% of the trips are above the 8-bit limit. Multimodal transportation systems in large cities have thus already exceeded human cognitive limits and, consequently, the traditional view of navigation in cities has to be revised substantially. PMID:26989769

  16. Lost in transportation: Information measures and cognitive limits in multilayer navigation.

    PubMed

    Gallotti, Riccardo; Porter, Mason A; Barthelemy, Marc

    2016-02-01

    Cities and their transportation systems become increasingly complex and multimodal as they grow, and it is natural to wonder whether it is possible to quantitatively characterize our difficulty navigating in them and whether such navigation exceeds our cognitive limits. A transition between different search strategies for navigating in metropolitan maps has been observed for large, complex metropolitan networks. This evidence suggests the existence of a limit associated with cognitive overload and caused by a large amount of information that needs to be processed. In this light, we analyzed the world's 15 largest metropolitan networks and estimated the information limit for determining a trip in a transportation system to be on the order of 8 bits. Similar to the "Dunbar number," which represents a limit to the size of an individual's friendship circle, our cognitive limit suggests that maps should not consist of more than 250 connection points to be easily readable. We also show that including connections with other transportation modes dramatically increases the information needed to navigate in multilayer transportation networks. In large cities such as New York, Paris, and Tokyo, more than 80% of the trips are above the 8-bit limit. Multimodal transportation systems in large cities have thus already exceeded human cognitive limits and, consequently, the traditional view of navigation in cities has to be revised substantially. PMID:26989769

  17. Challenges in Measuring and Predicting Medium Term (Weeks to Annual) Aeolian Sediment Transport in Beach-Dune Systems

    NASA Astrophysics Data System (ADS)

    Delgado-Fernandez, I.

    2009-05-01

    Coastal dune budgets depend on sediment input by wind from the beach. Calculation of aeolian transport is thus a primary factor to understand coastal dune evolution and beach-dune coupled dynamics. However, measuring aeolian sediment transport in coastal areas presents fundamental technical and conceptual limitations that make numerical modeling difficult. Wind tunnel experiments isolate and reduce the number of variables to study, which is a necessary procedure to clearly manifest mechanistic relationships between cause and effect. But even with refinement and inclusion of new variables, traditional sediment transport formulas derived from wind tunnel experiments do not usually work well in natural areas. Short-term experiments may include precise instrumentation to obtain high frequency, detail time series of variables involved in aeolian transport, but inferring information at larger scales is problematic without knowledge of the timing and magnitude of particular transport events. There are two primary problems in attempting to predict sediment inputs to coastal dunes over periods of weeks, months or years: 1) to determine an appropriate set of predictive equations that incorporate complexities such as surface moisture content, beach width and the presence of vegetation; and 2) to provide quantitative data on these variables for input into the model at this time scale. Remote sensing techniques and the use of GIS software open the possibility to monitor key parameters regulating sediment transport dynamics at high spatial and temporal resolution over time scales beyond short-term experiments. These were applied at Greenwich Dunes, Prince Edward Island National Park (Canada), in an attempt to measure factors affecting aeolian sediment input to the foredune at a medium scale. Three digital cameras covering different sections of the beach and foredune provide time series on shoreline position, fetch distances, vegetation cover, ice/snow presence, or superficial moisture content. The rectification of oblique images to UTM maps allows to keep the spatial variability of these factors, and thus to perform detailed analysis on their complex evolution. Auxiliary instrumentation such as anemometers, safires, or erosion-deposition pins completes the basic set up. Data is processed using ArcGIS 9.2 and PCI Geomatica 9.1, and managed by an ArcCatalog Geodatabase. The coupling of new technologies (digital imagery) with traditional instrumentation (e.g. anemometers), and the extensive GIS capabilities both in the spatial and temporal domain, permits a new set of questions in aeolian coastal research. The overall goal is to obtain information on what is the frequency and magnitude of transport events at the beach or what are the key parameters regulating them. Challenges remain in improving methodologies to measure sediment transport rates. Ironically enough, we are able to obtain high quality time series on the factors affecting aeolian transport at the beach, but actual transport rates are measured with rather rudimentary techniques or instrumentation not adapted to meso-scale monitoring. This information is needed to test new approaches in modeling and understanding aeolian sediment input from the beach to the foredunes.

  18. Measurement of carrier transport and recombination parameter in heavily doped silicon

    NASA Technical Reports Server (NTRS)

    Swanson, Richard M.

    1986-01-01

    The minority carrier transport and recombination parameters in heavily doped bulk silicon were measured. Both Si:P and Si:B with bulk dopings from 10 to the 17th and 10 to the 20th power/cu cm were studied. It is shown that three parameters characterize transport in bulk heavily doped Si: the minority carrier lifetime tau, the minority carrier mobility mu, and the equilibrium minority carrier density of n sub 0 and p sub 0 (in p-type and n-type Si respectively.) However, dc current-voltage measurements can never measure all three of these parameters, and some ac or time-transient experiment is required to obtain the values of these parameters as a function of dopant density. Using both dc electrical measurements on bipolar transitors with heavily doped base regions and transients optical measurements on heavily doped bulk and epitaxially grown samples, lifetime, mobility, and bandgap narrowing were measured as a function of both p and n type dopant densities. Best fits of minority carrier mobility, bandgap narrowing and lifetime as a function of doping density (in the heavily doped range) were constructed to allow accurate modeling of minority carrier transport in heavily doped Si.

  19. Serial Measurements of Apoptotic Cell Numbers Provide Better Acceptance Criterion for PBMC Quality than a Single Measurement Prior to the T Cell Assay

    PubMed Central

    Wunsch, Marie; Caspell, Richard; Kuerten, Stefanie; Lehmann, Paul V.; Sundararaman, Srividya

    2015-01-01

    As soon as Peripheral Blood Mononuclear Cells (PBMC) are isolated from whole blood, some cells begin dying. The rate of apoptotic cell death is increased when PBMC are shipped, cryopreserved, or stored under suboptimal conditions. Apoptotic cells secrete cytokines that suppress inflammation while promoting phagocytosis. Increased numbers of apoptotic cells in PBMC may modulate T cell functions in antigen-triggered T cell assays. We assessed the effect of apoptotic bystander cells on a T cell ELISPOT assay by selectively inducing B cell apoptosis using α-CD20 mAbs. The presence of large numbers of apoptotic B cells did not affect T cell functionality. In contrast, when PBMC were stored under unfavorable conditions, leading to damage and apoptosis in the T cells as well as bystander cells, T cell functionality was greatly impaired. We observed that measuring the number of apoptotic cells before plating the PBMC into an ELISPOT assay did not reflect the extent of PBMC injury, but measuring apoptotic cell frequencies at the end of the assay did. Our data suggest that measuring the numbers of apoptotic cells prior to and post T cell assays may provide more stringent PBMC quality acceptance criteria than measurements done only prior to the start of the assay. PMID:25585298

  20. Preliminary measurements of aromatic VOCs in public transportation modes in Guangzhou, China.

    PubMed

    Chan, L Y; Lau, W L; Wang, X M; Tang, J H

    2003-07-01

    This study examined the exposure level of aromatic volatile organic compounds (VOCs) in public transportation modes in Guangzhou, China. A total of 40 VOC samples were conducted in four popular public commuting modes (subway, taxis, non-air-conditioned buses and air-conditioned buses) while traversing in urban areas of Guangzhou. Traffic-related VOCs (benzene, toluene, ethylbenzene, m/p-xylene and o-xylene) were collected on adsorbent tubes and analyzed by thermal desorption (TD) and gas chromatography/mass-selective detector (GC/MSD) technique. The results indicate that commuter exposure to VOCs is greatly influenced by the choice of public transport. For the benzene measured, the mean exposure level in taxis (33.6 microg/m(3)) was the highest and was followed by air-conditioned buses (13.5 microg/m(3)) and non-air-conditioned buses (11.3 microg/m(3)). The exposure level in the subway (7.6 microg/m(3)) is clearly lower than that in roadway transports. The inter-microenvironment variations of other target compounds were similar to that of benzene. The target VOCs were well correlated to each other in all the measured transports. The concentration profile of the measured transport was also investigated and was found to be similar to each other. Based on the experiment results, the average B/T/E/X found in this study was about (1.0/4.3/0.7/1.4). In this study, the VOC levels measured in evening peak hours were only slightly higher than those in afternoon non-peak hours. This is due to the insignificant change of traffic volume on the measured routes between these two set times. The out-dated vehicle emission controls and slow-moving traffic conditions may be the major reasons leading elevated in-vehicle exposure level in some public commuting journeys. PMID:12705940

  1. Measurement of the absolute number of functioning low-density lipoprotein receptors in vivo using a monoclonal antibody.

    PubMed Central

    Fitzsimmons, C; Bush, R; Hele, D; Godliman, C; Gherardi, E; Bowyer, D E

    1995-01-01

    MAC188 S/S is a monoclonal antibody which can be used in vivo to measure the absolute number of functioning low-density lipoprotein (LDL) receptors in a rabbit. The antibody binds to the extra-cellular domain of the LDL receptor and binding is not blocked by the presence of LDL. When the antibody-receptor complex is internalized, receptor recycling is inhibited for several hours. Thus when saturating doses of MAC188 S/S are administered intravenously, the amount of antibody removed from the blood (minus non-specific removal) is determined solely by the total number of LDL receptors in an animal. In this study MAC188 S/S was used to measure the number of LDL receptors in control rabbits and in animals treated with 17 alpha-ethinyl oestradiol. After treatment (which caused a 47% decrease in plasma cholesterol), receptor-mediated removal of MAC188 S/S from the blood was saturated in both groups following injection of 3.0 mg of antibody per kg body weight. Based on the amount of antibody removed via the LDL receptor at this dose, the total number of accessible LDL receptors was calculated as (2.0 +/- 0.3) x 10(15) receptors per kg body weight in control rabbits and (4.0 +/- 0.4) x 10(15) receptors per kg body weight in oestrogen-treated animals. The number of receptors in various organs was also determined. The monoclonal antibody approach therefore, allows accurate determination of LDL receptor numbers in animals with markedly different concentrations of circulating LDL, conditions in which the use of endogenous ligand would be subject to significant errors. Images Figure 1 PMID:7848291

  2. Coincidence measurements between fragment ions and the number of emitted electrons in heavy ion collisions with polyatomic molecules

    NASA Astrophysics Data System (ADS)

    Murai, T.; Majima, T.; Kishimoto, T.; Tsuchida, H.; Itoh, A.

    2012-11-01

    We have studied multiple ionization and multifragmentation of a chlorofluorocarbon molecule, CH2FCF3, induced by collisions of 580-keV C+ ions. Coincidence measurements of product ions and the number of emitted electrons from CH2FCF3 were performed under charge-changing conditions of C+ → Cq+ (q = 0, 2, 3). A fully inclusive measurement regardless of outgoing projectile charge state was also performed by making coincidence with a pulsed ion beam. Mass distributions of fragment ions and number distributions of emitted electrons were both found to change greatly according to charge-changing conditions. Highly multiple ionization emitting up to about 10 electrons was observed in electron loss collisions.

  3. Turbulence measurement in a reacting and non-reacting shear layer at a high subsonic Mach number

    NASA Technical Reports Server (NTRS)

    Chang, C. T.; Marek, C. J.; Wey, C.; Jones, R. A.; Smith, M. J.

    1993-01-01

    The results of two component velocity and turbulence measurements are presented which were obtained on a planar reacting shear layer burning hydrogen. Quantitative LDV and temperature measurements are presented with and without chemical reaction within the shear layer at a velocity ratio of 0.34 and a high speed Mach number of 0.7. The comparison showed that the reacting shear layer grew faster than that without reaction. Using a reduced width coordinate, the reacting and non-reacting profiles were very similar. The peak turbulence for both cases was 20 percent.

  4. Dependence of Single-Interface Richtmyer-Meshkov Mixing on Mach Number using Simultaneous PIV and PLIF Measurements

    NASA Astrophysics Data System (ADS)

    Wilson, Brandon M.; Mejia-Alvarez, Ricardo; Prestridge, Kathy P.

    2013-11-01

    Richtmyer-Meshkov mixing is dependent upon initial interface perturbations, incident shock Mach number, Atwood number, and other fluid properties. The correlation between turbulence quantities and mixing parameters with these properties is not well-understood. The Vertical Shock Tube (VST) at Los Alamos National Lab is designed to measure turbulence and mixing from the Taylor micro-scale to the largest scales (mix width). We use simultaneous velocity (PIV) and density (PLIF) diagnostics to understand the effects of incident Mach number on statistically-invariant, multimode perturbations of an air-SF6 interface (Atwood number corrected for acetone diagnostic is A = 0.57). We quantify Ma effects on mixing at both large and small scales by measuring the time evolution of various mixing parameters (e . g . mixing width, Favre-averaged Reynolds stresses, and vorticity), and we compare these results to previous studies. Late mixing after the first shock resembles a turbulent flow, and we examine the nature of the turbulence and condition of turbulent transition.

  5. Mobile measurements of aerosol number and volume size distributions in an Alpine valley: Influence of traffic versus wood burning

    NASA Astrophysics Data System (ADS)

    Weimer, S.; Mohr, C.; Richter, R.; Keller, J.; Mohr, M.; Prévôt, A. S. H.; Baltensperger, U.

    The spatial variability of highly time resolved size distributions was investigated in a narrow valley which provides the opportunity to study the impact of different sources on ambient particle concentrations during summer and winter time. The measurements were performed with a Fast Mobility Particle Sizer (FMPS) from TSI, Inc. on a mobile laboratory in Southern Switzerland. The results indicate enhanced number concentrations (between 150 000 and 500 000 cm -3) along the busy highway A2 which is the main transit route through the Swiss Alps connecting the northern and southern part of Switzerland. Especially the nanoparticles with diameters lower than 30 nm showed strongly increased number concentrations on the highway both in summer and winter. In winter time, high aerosol volume concentrations (PM 0.3) were found in villages where wood burning is often used for heating purposes. Both traffic and wood burning were found to be important sources for particulate mass which accumulates during temperature inversions in winter time. Traffic was the dominant and wood burning a minor source for the nanoparticle number concentration. This is important regarding health impacts and its attribution to different sources because wood burning might contribute most to particulate mass whereas at the same time and place traffic contributes most to particulate number. In addition, during summer time volatility measurements were performed with the FMPS showing that the nucleation mode prevalently seen on the highway was removed by more than 95% by thermal treatment.

  6. Cosmic-ray abundances of elements with atomic number 26 less than or equal to 40 measured on HEAO 3

    NASA Technical Reports Server (NTRS)

    Binns, W. R.; Fickle, R. K.; Waddington, C. J.; Garrard, T. L.; Stone, E. C.; Israel, M. H.; Klarmann, J.

    1981-01-01

    Individual elements in the cosmic radiation of even atomic number (Z) in the interval 26-40 have been resolved and their relative abundances measured. The results are inconsistent with a cosmic-ray source whose composition in this charge interval is dominated by r-process nucleosynthesis. The ratios of cosmic-ray source abundances to solar system abundances in this interval follow the same general correlation with first ionization potential as for the lighter elements, although there are deviations in detail.

  7. Phonon-magnon interaction in low dimensional quantum magnets observed by dynamic heat transport measurements.

    PubMed

    Montagnese, Matteo; Otter, Marian; Zotos, Xenophon; Fishman, Dmitry A; Hlubek, Nikolai; Mityashkin, Oleg; Hess, Christian; Saint-Martin, Romuald; Singh, Surjeet; Revcolevschi, Alexandre; van Loosdrecht, Paul H M

    2013-04-01

    Thirty-five years ago, Sanders and Walton [Phys. Rev. B 15, 1489 (1977)] proposed a method to measure the phonon-magnon interaction in antiferromagnets through thermal transport which so far has not been verified experimentally. We show that a dynamical variant of this approach allows direct extraction of the phonon-magnon equilibration time, yielding 400 μs for the cuprate spin-ladder system Ca(9)La(5)Cu(24)O(41). The present work provides a general method to directly address the spin-phonon interaction by means of dynamical transport experiments. PMID:25167033

  8. Computer-implemented remote sensing techniques for measuring coastal productivity and nutrient transport systems

    NASA Technical Reports Server (NTRS)

    Butera, M. K.

    1981-01-01

    An automatic technique has been developed to measure marsh plant production by inference from a species classification derived from Landsat MSS data. A separate computer technique has been developed to calculate the transport path length of detritus and nutrients from their point of origin in the marsh to the shoreline from Landsat data. A nutrient availability indicator, the ratio of production to transport path length, was derived for each marsh-identified Landsat cell. The use of a data base compatible with the Landsat format facilitated data handling and computations.

  9. Spatially resolved in situ measurements of the transport of organic molecules in a polycrystalline nanoporous membrane

    NASA Astrophysics Data System (ADS)

    Oh, Weontae; Nair, Sankar

    2005-10-01

    We report spatially resolved, quantitative, in situ, nondestructive measurements of the transport of organic molecules through a polycrystalline, anisotropic, nanoporous molecular sieve membrane, with micron-scale resolution. A method based on photoacoustic spectroscopy experiments during permeation through a nanoporous membrane, combined with a physical model of photoacoustic signal generation from a heterogeneous membrane, allows extraction of concentration profiles in situ. In particular, we demonstrate the steady-state concentration profiling of the organic molecules p-xylene and n-hexane during their transport through a nanoporous zeolite silicalite membrane. The implications for elucidating structure-property relationships in membrane materials for separations, catalytic, or nanotechnology applications are discussed.

  10. Correlating spin transport and electrode magnetization in a graphene spin valve: Simultaneous magnetic microscopy and non-local measurements

    SciTech Connect

    Berger, Andrew J. Page, Michael R.; Bhallamudi, Vidya P.; Chris Hammel, P.; Wen, Hua; Kawakami, Roland K.; McCreary, Kathleen M.

    2015-10-05

    Using simultaneous magnetic force microscopy and transport measurements of a graphene spin valve, we correlate the non-local spin signal with the magnetization of the device electrodes. The imaged magnetization states corroborate the influence of each electrode within a one-dimensional spin transport model and provide evidence linking domain wall pinning to additional features in the transport signal.

  11. Spin transport parameters in metallic multilayers determined by ferromagnetic resonance measurements of spin-pumping

    SciTech Connect

    Boone, C. T.; Nembach, Hans T.; Shaw, Justin M.; Silva, T. J.

    2013-04-21

    We measured spin-transport in nonferromagnetic (NM) metallic multilayers from the contribution to damping due to spin pumping from a ferromagnetic Co{sub 90}Fe{sub 10} thin film. The multilayer stack consisted of NM{sub 1}/NM{sub 2}/Co{sub 90}Fe{sub 10}(2 nm)/NM{sub 2}/NM{sub 3} with varying NM materials and thicknesses. Using conventional theory for one-dimensional diffusive spin transport in metals, we show that the effective damping due to spin pumping can be strongly affected by the spin transport properties of each NM in the multilayer, which permits the use of damping measurements to accurately determine the spin transport properties of the various NM layers in the full five-layer stack. We find that due to its high electrical resistivity, amorphous Ta is a poor spin conductor, in spite of a short spin-diffusion length of 1.0 nm, and that Pt is an excellent spin conductor by virtue of its low electrical resistivity and a spin diffusion length of only 0.5 nm. Spin Hall effect measurements may have underestimated the spin Hall angle in Pt by assuming a much longer spin diffusion length.

  12. Characterization of the transport properties of channel delta-doped structures by light-modulated Shubnikov-de Haas measurements

    NASA Astrophysics Data System (ADS)

    Mena, R. A.; Schacham, S. E.; Haugland, E. J.; Alterovitz, S. A.; Young, P. G.; Bibyk, S. B.; Ringel, S. A.

    1995-12-01

    The transport properties of channel delta-doped quantum-well structures were characterized by conventional Hall effect and light-modulated Shubnikov-de Haas (SdH) effect measurements. The large number of carriers that become available due to the delta doping of the channel, leads to an apparent degeneracy in the well. As a result of this degeneracy, the carrier mobility remains constant as a function of temperature from 300 down to 1.4 K. The large amount of impurity scattering, associated with the overlap of the charge carriers and the dopants, resulted in low carrier mobilities and restricted the observation of the oscillatory magnetoresistance used to characterize the two-dimensional electron gas by conventional SdH measurements. By light modulating the carriers, we were able to observe the SdH oscillation at low magnetic fields, below 1.4 T, and derive a value for the quantum scattering time. Our results for the ratio of the transport and quantum scattering times are lower than those previously measured for similar structures using much higher magnetic fields.

  13. Characterization of the transport properties of channel delta-doped structures by light-modulated Shubnikov-de Haas measurements

    NASA Astrophysics Data System (ADS)

    Mena, R. A.; Schacham, S. E.; Haugland, E. J.; Alterovitz, S. A.; Young, P. G.; Bibyk, S. B.; Ringel, S. A.

    1995-08-01

    The transport properties of channel delta-doped quantum well structures were characterized by conventional Hall effect and light-modulated Shubnikov-de Haas (SdH) effect measurements. The large number of carriers that become available due to the delta-doping of the channel, leads to an apparent degeneracy in the well. As a result of this degeneracy, the carrier mobility remains constant as a function of temperature from 300 K down to 1.4 K. The large amount of impurity scattering, associated with the overlap of the charge carriers and the dopants, resulted in low carrier mobilities and restricted the observation of the oscillatory magneto-resistance used to characterize the two-dimensional electron gas (2DEG) by conventional SdH measurements. By light-modulating the carriers, we were able to observe the SdH oscillation at low magnetic fields, below 1.4 tesla, and derive a value for the quantum scattering time. Our results for the ratio of the transport and quantum scattering times are lower than those previously measured for similar structures using much higher magnetic fields.

  14. Characterization of the transport properties of channel delta-doped structures by light-modulated Shubnikov-de Haas measurements

    NASA Technical Reports Server (NTRS)

    Mena, R. A.; Schacham, S. E.; Haugland, E. J.; Alterovitz, S. A.; Young, P. G.; Bibyk, S. B.; Ringel, S. A.

    1995-01-01

    The transport properties of channel delta-doped quantum well structures were characterized by conventional Hall effect and light-modulated Shubnikov-de Haas (SdH) effect measurements. The large number of carriers that become available due to the delta-doping of the channel, leads to an apparent degeneracy in the well. As a result of this degeneracy, the carrier mobility remains constant as a function of temperature from 300 K down to 1.4 K. The large amount of impurity scattering, associated with the overlap of the charge carriers and the dopants, resulted in low carrier mobilities and restricted the observation of the oscillatory magneto-resistance used to characterize the two-dimensional electron gas (2DEG) by conventional SdH measurements. By light-modulating the carriers, we were able to observe the SdH oscillation at low magnetic fields, below 1.4 tesla, and derive a value for the quantum scattering time. Our results for the ratio of the transport and quantum scattering times are lower than those previously measured for similar structures using much higher magnetic fields.

  15. CFD Study of Pectoral Fins of Larval Zebrafish: Effect of Reynolds Number and Fin Bending in Fluid Structures and Transport

    NASA Astrophysics Data System (ADS)

    Islam, Toukir; Curet, Oscar M.

    2015-11-01

    Zebrafish exhibits significant changes in fin morphology as well as fin actuation during its physical development. In larval stage (Re ~ 10), they beat pectoral fins asymmetrically during slow swimming and prey tracking and a hypothesis suggests pectoral fin motion enhances fluid mixing to assist respiration. We performed a series of computational simulations to study effect of Reynolds number (Re) and pectoral fin kinematics in the fluid dynamics and mixing around a larval zebrafish. The CFD algorithm is based on a constraint formulation where the kinematics of the zebrafish are specified. We simulated experimental zebrafish kinematics at different Re (17 to 300) and considered variations on the fin kinematics to evaluate role of fin deformation in the fluid structures generated by the pectoral fins. Using Lagrangian Coherent Structures and Lagrangian fluid tracers, we identified distinctly dynamic fluid regions and found that mixing around the pectoral fin significantly increases with Re and fin bending enhance fluid mixing at low Re. However, as zebrafish matures and its Re increases, the need to beat the pectoral fins to enhance mixing is reduced.

  16. Measurement of electron transport in the Madison Symmetric Torus Reversed Field Pinch

    SciTech Connect

    Lanier, N.E.; Craig, D.; Anderson, J.K.; Biewer, T.M.; Chapman, B.E.; Den Hartog, D.J.; Forest, C.B.; Prager, S.C.; Brower, D.L.; Jiang, Y.

    2001-01-01

    A recent study investigating the role of electron density fluctuations in particle transport has been conducted on the Madison Symmetric Torus reversed field pinch. Four diagnostics enabled this experiment: a high-speed multichord far-infrared laser interferometer, a multichord H array, a 64- position magnetic coil array, and a Doppler spectrometer that measured impurity ion flow fluctuations. Correlation analysis is used to elucidate the relationship among density, magnetic and impurity ion flow fluctuations. We observe that the electron density fluctuations are highly coherent with magnetic fluctuations resulting from core-resonant resistive tearing modes. Moreover, the fluctuation-induced particle transport, obtained from the correlation between electron density and flow fluctuationism indicates that the core-resonant tearing modes do not drive significant particle transport in the plasma edge. We will address these four primary diagnostics, details of the analysis techniques and principals from this study.

  17. Relationship of number of phases per cardiac cycle and accuracy of measurement of left ventricular volumes, ejection fraction, and mass.

    PubMed

    Roussakis, Arkadios; Baras, Panagiotis; Seimenis, Ioannis; Andreou, John; Danias, Peter G

    2004-01-01

    In cine cardiac magnetic resonance imaging (MRI) studies, for any preset imaging parameters the number of phases per cardiac cycle for a single slice is proportional to breath-hold duration. We investigated the relationship between the accuracy of measurement of left ventricular (LV) end-diastolic and end-systolic volumes (EDV and ESV, respectively), mass and ejection fraction (EF), and the number of phases acquired per cardiac cycle. Twelve adult volunteers underwent cardiac MRI and five complete LV functional studies were obtained with 8, 11, 14, 17, and 20 phases per cardiac cycle. We calculated LV volumes, EF, and mass for each acquisition, and compared them using the 20-phase acquisition as the reference standard. The scan duration was proportional to the number of phases acquired. There was a systematic underestimation of LV, EDV, and EF, with decreasing number of phases. Differences from the reference standard became significant for the 8-phase acquisition (p<0.05). Subgroup analysis showed that only those with slower heart rates (<65/min) had significant differences in EDV, but not in EF, for the 8-phase acquisition. For those with faster heart rates, no differences were detected between the different acquisitions. There were no significant differences between all acquisitions for the LV ESV and mass. We conclude that at least 11 phases per cardiac cycle are needed to maintain accuracy for cine cardiac MRI studies. Decreasing the number of phases per cardiac cycle beyond this cutoff may introduce significant error of measurement, particularly for the left ventricular EDV and EF and especially for those with bradycardia, and should be avoided. PMID:15646887

  18. Evidence of transport processes in the carbon monoxide(CO) data from the measurement of pollution in the troposphere

    NASA Astrophysics Data System (ADS)

    Kar, J.; Mopitt Team

    MOPITT was launched aboard the Terra spacecraft in December 1999 into a sun synchronous orbit at 705 km and has been retrieving vertical profiles of CO globally since March 2000. The retrievals have been validated by comparison with in-situ aircraft measurements through a regular program as well through special field campaigns. In this paper we examine the role of CO as a tracer of transport using MOPITT data. The problem of limited vertical resolution of MOPITT retrievals is alleviated to a certain extent by the large number of profiles at any place. Case studies showing signatures of convection and Stratosphere-Troposphere Transport (STE) in the MOPITT CO data will be presented with supporting evidence from back trajectories, potential vorticity and ozonesonde data. The zonal mean height latitude cross sections of CO for various months indicate convective transport from biomass burning in the southern tropics during September-November period. Further, the boundary between the polluted northern hemisphere and relatively clean southern hemisphere shows a seasonal migration in latitude that has similarities with the migration of the inter tropical convergence zone. Possible signatures of the downward branch of the Hadley cell could also be seen in the northern hemisphere.

  19. Retrieval of sodium number density profiles in the mesosphere and lower thermosphere from SCIAMACHY limb emission measurements

    NASA Astrophysics Data System (ADS)

    Langowski, M. P.; von Savigny, C.; Burrows, J. P.; Rozanov, V. V.; Dunker, T.; Hoppe, U.-P.; Sinnhuber, M.; Aikin, A. C.

    2016-01-01

    An algorithm has been developed for the retrieval of sodium atom (Na) number density on a latitude and altitude grid from SCIAMACHY (SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY) limb measurements of the Na resonance fluorescence. The results are obtained between 50 and 150 km altitude and the resulting global seasonal variations of Na are analyzed. The retrieval approach is adapted from that used for the retrieval of magnesium atom (Mg) and magnesium ion (Mg+) number density profiles recently reported by Langowski et al. (2014). Monthly mean values of Na are presented as a function of altitude and latitude. This data set was retrieved from the 4 years of spectroscopic limb data of the SCIAMACHY mesosphere and lower thermosphere (MLT) measurement mode (mid-2008 to early 2012). The Na layer has a nearly constant peak altitude of 90-93 km for all latitudes and seasons, and has a full width at half maximum of 5-15 km. Small but significant seasonal variations in Na are identified for latitudes less than 40, where the maximum Na number densities are 3000-4000 atoms cm-3. At middle to high latitudes a clear seasonal variation with a winter maximum of up to 6000 atoms cm-3 is observed. The high latitudes, which are only measured in the summer hemisphere, have lower number densities, with peak densities being approximately 1000 Na atoms cm-3. The full width at half maximum of the peak varies strongly at high latitudes and is 5 km near the polar summer mesopause, while it exceeds 10 km at lower latitudes. In summer the Na atom concentration at high latitudes and at altitudes below 88 km is significantly smaller than that at middle latitudes. The results are compared with other observations and models and there is overall a good agreement with these.

  20. Simultaneous measurement of deltapH and electron transport in chloroplast thylakoids by 9-aminoacridine fluorescence.

    PubMed

    Evron, Y; McCarty, R E

    2000-09-01

    Electron transport and the electrochemical proton gradient across the thylakoid membrane are two fundamental parameters of photosynthesis. A combination of the electron acceptor, ferricyanide and the DeltapH indicator, 9-aminoacridine, was used to measure simultaneously electron transport rates and DeltapH solely by changes in the fluorescence of 9-aminoacridine. This method yields values for the rate of electron transport that are comparable with those obtained by established methods. Using this method a relationship between the rate of electron transport and DeltapH at various uncoupler concentrations or light intensities was obtained. In addition, the method was used to study the effect of reducing the disulfide bridge in the gamma-subunit of the chloroplast ATP synthase on the relation of electron transport to DeltapH. When the ATP synthase is reduced and alkylated, the threshold DeltapH at which the ATP synthase becomes leaky to protons is lower compared with the oxidized enzyme. Proton flow through the enzyme at a lower DeltapH may be a key step in initiation of ATP synthesis in the reduced enzyme and may be the way by which reduction of the disulfide bridge in the gamma-subunit enables high rates of ATP synthesis at low DeltapH values. PMID:10982453

  1. Water and Solute Transport in Arid Vadose Zones: Innovations in Measurement and Analysis

    SciTech Connect

    Tyler, S W.; Scanlon, Bridget R.; Gee, Glendon W.; Allison, G B.; M. B. Parlange and J. W. Hopmans

    1999-12-01

    Understanding the physics of flow and transport through the vadose zone has advanced significantly in the last three decades. These advances have been made primarily in humid regions or in irrigated agricultural settings. While some of the techniques are useful, many are not suited to arid regions. The fluxes of water and solutes typically found in arid regions are often orders of magnitude smaller than those found in agricultural settings, while the time scales for transport can be orders of magnitude larger. The depth over which transport must be characterized is also often much greater than in humid regions. Rather than relying on advances in applied tracers, arid-zone researchers have developed natural tracer techniques that are capable of quantifying transport over tens to thousands of years. Techniques have been developed to measure the hydraulic properties of sediments at all water contents, including the very dry range and at far greater depths. As arid and semiarid regions come under increased development pressures for such activities as hazardous- and radioactive-waste disposal, the development of techniques and the understanding of water and solute transport have become crucial components in defining the environmental impacts of activities at the landsurface.

  2. Measurement of Nutrient Transport and Uptake Parameters in Streams Using a Pulse Injection

    NASA Astrophysics Data System (ADS)

    Haggerty, R.; Argerich, A.

    2009-12-01

    Calculation of transport and uptake parameters in streams such as As/A, ts, Sw, and Vf is usually accomplished with a steady-state injection and a transport simulator such as OTIS [Runkel, 1998]. A steady-state injection is infeasible if ts is large or if discharge is high. However, a pulse injection measured at one or multiple downstream locations makes the experiment feasible even for high discharge [Tank et al., 2008], but creates challenges for data interpretation. We generate a set of simple equations for calculation of transport and uptake parameters from a pulse injection without the need for a transport simulator by extending the method of moments. The moment equations include decay parameters that are different between the channel and the transient storage zone. Moment equations can also be written for decay products, multiple timescales of exchange, and multiple decay rates. The method of moments is less dependent on the details of the exchange model than transport simulators, and so some parameters can be calculated independently from any assumptions about exchange timescales.

  3. PTV measurements of Lagrangian particle transport by surface gravity wave groups

    NASA Astrophysics Data System (ADS)

    van den Bremer, Ton; Whittaker, Colin; Raby, Alison; Taylor, Paul

    2015-11-01

    We present detailed PTV (particle tracking velocimetry) measurements of the Lagrangian transport and trajectories of neutrally buoyant particles underneath two-dimensional surface gravity wave groups in a laboratory flume. By focussing our attention on wave groups of moderate steepness, we confirm the predictions of standard second-order multi-chromatic wave theory, in which the body of fluid satisfies the potential flow equations. Particles near the surface are transported forwards and their motion is dominated by Stokes drift. Particles at sufficient depth are transported backwards by the Eulerian return current that was first described by Longuet-Higgins & Stewart (1962) and forms an inseparable counterpart of Stokes drift for surface wave groups ensuring the (irrotational) mass balance holds. Finally, we provide experimental validation of a simple scaling relationship, derived based under the assumption of separation of scales, for the transition depth: the depth above which Lagrangian particles are transported forwards by the Stokes drift and below which such particles are transported backwards by the return current. We present results for a range of effective water depths.

  4. Duration of High Flow Releases from Dams: Insights from Recent Bedload Transport Measurements

    NASA Astrophysics Data System (ADS)

    Hales, G.; Pryor, C.; McBain, S.

    2006-12-01

    Assessments to prescribe flow releases from dams have historically focused on baseflow releases, typically to satisfy fish habitat, recreation, or other biological objectives. High flow releases that exceed fluvial geomorphic thresholds are being increasingly prescribed to satisfy restoration objectives on regulated rivers. High flow releases must consider flow magnitude, duration, frequency, timing, and rate of change. The role of peak flow release magnitude in accomplishing restoration objectives is much better understood than is the role of peak flow release duration. Is a flow release of 10,000 cubic feet per second (cfs) for ten days twice as "effective" as a 10,000 cfs release for five days? Duration has been a more challenging prescriptive parameter because of: (1) high sensitivity to overall water volume, and (2) uncertainty in how it satisfies fluvial geomorphic and ecological objectives (e.g., bedload transport, channel migration, fish rearing, and riparian vegetation). Using bedload transport rate as an index of fluvial geomorphic work, bedload transport was repeatedly measured on two California streams over prolonged steady high flow releases to assess the role of duration. Preliminary results suggest that bedload transport rates dropped significantly after two to three days of prolonged steady high flow release. While bedload transport is only one of several potential objectives addressed by high flow duration, application of these results to high flow management suggests that short duration, high magnitude flow releases are more efficient at satisfying some fluvial geomorphic objectives than longer duration, moderate magnitude flow releases.

  5. DUF1220 copy number is linearly associated with increased cognitive function as measured by total IQ and mathematical aptitude scores.

    PubMed

    Davis, Jonathon M; Searles, Veronica B; Anderson, Nathan; Keeney, Jonathon; Raznahan, Armin; Horwood, L John; Fergusson, David M; Kennedy, Martin A; Giedd, Jay; Sikela, James M

    2015-01-01

    DUF1220 protein domains exhibit the greatest human lineage-specific copy number expansion of any protein-coding sequence in the genome, and variation in DUF1220 copy number has been linked to both brain size in humans and brain evolution among primates. Given these findings, we examined associations between DUF1220 subtypes CON1 and CON2 and cognitive aptitude. We identified a linear association between CON2 copy number and cognitive function in two independent populations of European descent. In North American males, an increase in CON2 copy number corresponded with an increase in WISC IQ (R (2) = 0.13, p = 0.02), which may be driven by males aged 6-11 (R (2) = 0.42, p = 0.003). We utilized ddPCR in a subset as a confirmatory measurement. This group had 26-33 copies of CON2 with a mean of 29, and each copy increase of CON2 was associated with a 3.3-point increase in WISC IQ (R (2) = 0.22, p = 0.045). In individuals from New Zealand, an increase in CON2 copy number was associated with an increase in math aptitude ability (R (2) = 0.10 p = 0.018). These were not confounded by brain size. To our knowledge, this is the first study to report a replicated association between copy number of a gene coding sequence and cognitive aptitude. Remarkably, dosage variations involving DUF1220 sequences have now been linked to human brain expansion, autism severity and cognitive aptitude, suggesting that such processes may be genetically and mechanistically inter-related. The findings presented here warrant expanded investigations in larger, well-characterized cohorts. PMID:25287832

  6. Measuring the misfit between seismograms using an optimal transport distance: application to full waveform inversion

    NASA Astrophysics Data System (ADS)

    Métivier, L.; Brossier, R.; Mérigot, Q.; Oudet, E.; Virieux, J.

    2016-04-01

    Full waveform inversion using the conventional L2 distance to measure the misfit between seismograms is known to suffer from cycle skipping. An alternative strategy is proposed in this study, based on a measure of the misfit computed with an optimal transport distance. This measure allows to account for the lateral coherency of events within the seismograms, instead of considering each seismic trace independently, as is done generally in full waveform inversion. The computation of this optimal transport distance relies on a particular mathematical formulation allowing for the non-conservation of the total energy between seismograms. The numerical solution of the optimal transport problem is performed using proximal splitting techniques. Three synthetic case studies are investigated using this strategy: the Marmousi 2 model, the BP 2004 salt model, and the Chevron 2014 benchmark data. The results emphasize interesting properties of the optimal transport distance. The associated misfit function is less prone to cycle skipping. A workflow is designed to reconstruct accurately the salt structures in the BP 2004 model, starting from an initial model containing no information about these structures. A high-resolution P-wave velocity estimation is built from the Chevron 2014 benchmark data, following a frequency continuation strategy. This estimation explains accurately the data. Using the same workflow, full waveform inversion based on the L2 distance converges towards a local minimum. These results yield encouraging perspectives regarding the use of the optimal transport distance for full waveform inversion: the sensitivity to the accuracy of the initial model is reduced, the reconstruction of complex salt structure is made possible, the method is robust to noise, and the interpretation of seismic data dominated by reflections is enhanced.

  7. Spectroscopic and transport measurements of single molecules in solution using an electrokinetic trap

    NASA Astrophysics Data System (ADS)

    Wang, Quan; Moerner, W. E.

    2014-03-01

    In aqueous solution, diffusion generally limits the observation window of a nano-meter sized single molecule to milliseconds and prevents quantitative determination of spectroscopic and transport properties molecule-by-molecule. The anti-Brownian electrokinetic (ABEL) trap is a feedback-based microfluidic device that enables prolonged (multiseconds) observation of single molecules in solution. The amount of information that can be extracted from each molecule in solution is thus boosted by three orders of magnitude. We describe recent advances in extending the ABEL trap to conduct both spectroscopic and transport measurements of single trapped molecules. First, by combining the trap with multi-parameter fluorescence detection, synchronized dynamics in different observables can be visualized in solution. We use single molecules of Atto 633 as an example and show that this popular label switches between different emissive states under common imaging conditions. Next, we show how transport properties of trapped single molecules can be extracted in addition to spectroscopic readouts. Due to their direct sensitivity to molecular size and charge, measured transport coefficients can be used to distinguish different molecular species and trace biomolecular interactions in solution. We demonstrate this new paradigm by monitoring DNA hybridization/melting in real-time.

  8. Hall-Effect Measurements Under AC Excitation for the Reconstruction of Obliterated Serial Numbers in Magnetic Steels

    NASA Astrophysics Data System (ADS)

    Johnson, M. J.; Lo, C. C. H.; Naidu, L. B.

    2004-02-01

    Existing forensic techniques employed to recover obliterated serial numbers fall mainly into one of two categories, those requiring extensive sample preparation including the use of acid etchants, and those utilizing magnetic particles to image irregularities in surface magnetic properties. The former is time consuming and utilizes potentially harmful chemicals while the latter messy and potentially low in sensitivity. A new approach is being investigated whereby the stray magnetic field is measured using a Hall effect sensor. The sample is magnetized using an electromagnetic c-core yoke. For increased sensitivity, an AC approach is being utilized that benefits from the use of a lock-in amplifier. The approach has been tested on some artificial specimens and part of a real gun with the serial numbers removed by surface grinding.

  9. Electronic structure and transport measurements of amorphous transition-metal oxides: observation of Fermi glass behavior

    NASA Astrophysics Data System (ADS)

    Goldfarb, I.; Miao, F.; Yang, J. Joshua; Yi, W.; Strachan, J. P.; Zhang, M.-X.; Pickett, M. D.; Medeiros-Ribeiro, G.; Williams, R. Stanley

    2012-04-01

    We characterized the conduction mechanisms in thin sputtered films of three representative binary Me-O (Me=Ta, W, and Nb) systems as a function of oxygen content, by combining in situ chemical state and electronic band structure studies from X-ray photoemission with temperature-dependent transport measurements. Despite certain differences, these amorphous films all displayed Fermi glass behavior following an oxidation-induced transition from metallic to hopping conduction, down to a sub-percolation threshold. The electron localization estimated from the band structure was in good agreement with that from the transport measurements, and the two were used to construct phase diagrams of conduction in the degree of oxidation-conductivity coordinates, which should prove important in the design of resistive switching and other electronic devices.

  10. Theoretical and measured aeolian sand transport on a barrier island, Louisiana, USA

    USGS Publications Warehouse

    Dingler, J.R.; Hsu, S.A.; Reiss, T.E.

    1992-01-01

    Over the past 100 yr, the Isles Dernieres, a low lying barrier island chain along the coast of central Louisiana, has undergone more than 1km of northward beach face retreat within the loss of 70% of its surface area. The erosion results from a long term relative sea level rise coupled with day to day wind and wave action that ultimately favours erosion over deposition. The theoretical estimate of 1.28 m3 m-1 for the rate of sand transport by the northerly wind compares well with the measured backshore erosion rate of 1.26m3 m-1, which was determined by comparing beach profiles from the start and end of the period of northerly winds. The theoretical estimate of 0.04m3 m-1 for the rate of sand transport by the southerly wind, however, is notably less than the measured rate of 0.45m3 m-1. -from Authors

  11. Using RFID and accelerometer-embedded tracers to measure probabilities of bed load transport, step lengths, and rest times in a mountain stream

    NASA Astrophysics Data System (ADS)

    Olinde, Lindsay; Johnson, Joel P. L.

    2015-09-01

    We present new measurements of bed load tracer transport in a mountain stream over several snowmelt seasons. Cumulative displacements were measured using passive tracers, which consisted of gravel and cobbles embedded with radio frequency identification tags. The timing of bed load motion during 11 transporting events was quantified with active tracers, i.e., accelerometer-embedded cobbles. Probabilities of cobble transport increased with discharge above a threshold, and exhibited slight to moderate hysteresis during snowmelt hydrographs. Dividing cumulative displacements by the number of movements recorded by each active tracer constrained average step lengths. Average step lengths increased with discharge, and distributions of average step lengths and cumulative displacements were thin tailed. Distributions of rest times followed heavy-tailed power law scaling. Rest time scaling varied somewhat with discharge and with the degree to which tracers were incorporated into the streambed. The combination of thin-tailed displacement distributions and heavy-tailed rest time distributions predict superdiffusive dispersion.

  12. Effect of data length and bin numbers on distribution entropy (DistEn) measurement in analyzing healthy aging.

    PubMed

    Udhayakumar, Radhagayathri K; Karmakar, Chandan; Peng Li; Palaniswami, Marimuthu

    2015-08-01

    Complexity analysis of a given time series is executed using various measures of irregularity, the most commonly used being Approximate entropy (ApEn), Sample entropy (SampEn) and Fuzzy entropy (FuzzyEn). However, the dependence of these measures on the critical parameter of tolerance `r' leads to precarious results, owing to random selections of r. Attempts to eliminate the use of r in entropy calculations introduced a new measure of entropy namely distribution entropy (DistEn) based on the empirical probability distribution function (ePDF). DistEn completely avoids the use of a variance dependent parameter like r and replaces it by a parameter M, which corresponds to the number of bins used in the histogram to calculate it. When tested for synthetic data, M has been observed to produce a minimal effect on DistEn as compared to the effect of r on other entropy measures. Also, DistEn is said to be relatively stable with data length (N) variations, as far as synthetic data is concerned. However, these claims have not been analyzed for physiological data. Our study evaluates the effect of data length N and bin number M on the performance of DistEn using both synthetic and physiologic time series data. Synthetic logistic data of `Periodic' and `Chaotic' levels of complexity and 40 RR interval time series belonging to two groups of healthy aging population (young and elderly) have been used for the analysis. The stability and consistency of DistEn as a complexity measure as well as a classifier have been studied. Experiments prove that the parameters N and M are more influential in deciding the efficacy of DistEn performance in the case of physiologic data than synthetic data. Therefore, a generalized random selection of M for a given data length N may not always be an appropriate combination to yield good performance of DistEn for physiologic data. PMID:26738118

  13. A Need-Based Measure of Consumer Well Being (CWB) in Relation to Personal Transportation: Nomological Validation

    ERIC Educational Resources Information Center

    Sirgy, M. Joseph; Lee, Dong-Jin; Kressmann, Frank

    2006-01-01

    This paper reports the results of three studies designed to test the nomological validity of a consumer well-being (CWB) measure in relation to personal transportation. The CWB measure was developed guided by the theoretical notion that the CWB in relation to personal transportation vehicles is significantly enhanced when the consumption of the…

  14. Two-path transport measurements with bias dependence on a triple quantum dot

    SciTech Connect

    Kotzian, M.; Rogge, M. C.; Haug, R. J.

    2013-12-04

    We present transport measurements on a lateral triple quantum dot with a star-like geometry and one lead attached to each dot. The system is studied in a regime close to established quadruple points, where all three dots are in resonance. The specific sample structure allows us to apply two different bias voltages to the two source leads and thus to study the influence between the paths with serial double dots.

  15. Measurement of energetic-particle-driven core magnetic fluctuations and induced fast-ion transport

    SciTech Connect

    Lin, L.; Ding, W. X.; Brower, D. L.; Koliner, J. J.; Eilerman, S.; Reusch, J. A.; Anderson, J. K.; Nornberg, M. D.; Sarff, J. S.; Waksman, J.; Liu, D.

    2013-03-15

    Internal fluctuations arising from energetic-particle-driven instabilities, including both density and radial magnetic field, are measured in a reversed-field-pinch plasma. The fluctuations peak near the core where fast ions reside and shift outward along the major radius as the instability transits from the n = 5 to n = 4 mode. During this transition, strong nonlinear three-wave interaction among multiple modes accompanied by enhanced fast-ion transport is observed.

  16. Sediment transport time measured with U-Series isotopes: Resultsfrom ODP North Atlantic Drill Site 984

    SciTech Connect

    DePaolo, Donald J.; Maher, Kate; Christensen, John N.; McManus,Jerry

    2006-06-05

    High precision uranium isotope measurements of marineclastic sediments are used to measure the transport and storage time ofsediment from source to site of deposition. The approach is demonstratedon fine-grained, late Pleistocene deep-sea sediments from Ocean DrillingProgram Site 984A on the Bjorn Drift in the North Atlantic. The sedimentsare siliciclastic with up to 30 percent carbonate, and dated by sigma 18Oof benthic foraminifera. Nd and Sr isotopes indicate that provenance hasoscillated between a proximal source during the last three interglacialperiods volcanic rocks from Iceland and a distal continental sourceduring glacial periods. An unexpected finding is that the 234U/238Uratios of the silicate portion of the sediment, isolated by leaching withhydrochloric acid, are significantly less than the secular equilibriumvalue and show large and systematic variations that are correlated withglacial cycles and sediment provenance. The 234U depletions are inferredto be due to alpha-recoil loss of234Th, and are used to calculate"comminution ages" of the sediment -- the time elapsed between thegeneration of the small (<_ 50 mu-m) sediment grains in the sourceareas by comminution of bedrock, and the time of deposition on theseafloor. Transport times, the difference between comminution ages anddepositional ages, vary from less than 10 ky to about 300 to 400 ky forthe Site 984A sediments. Long transport times may reflect prior storagein soils, on continental shelves, or elsewhere on the seafloor. Transporttime may also be a measure of bottom current strength. During the mostrecent interglacial periods the detritus from distal continental sourcesis diluted with sediment from Iceland that is rapidly transported to thesite of deposition. The comminution age approach could be used to dateQuaternary non-marine sediments, soils, and atmospheric dust, and may beenhanced by concomitant measurement of 226Ra/230Th, 230Th/234U, andcosmogenic nuclides.

  17. Polysulfide transport through separators measured by a linear voltage sweep method

    NASA Astrophysics Data System (ADS)

    Cui, Yi; Fu, Yongzhu

    2015-07-01

    Shuttle of polysulfide from the sulfur cathode to lithium metal anode in rechargeable lithium-sulfur batteries is a critical issue hindering cycling efficiency and life. Several approaches have been developed to minimize it including polysulfide-blocking separators; there is a need for measuring polysulfide transport through separators. We here show a linear voltage sweep method to measure anodic (oxidization) current of polysulfide crossed separators, which can be used as a quantitative measurement of the polysulfide transport. The electrochemical oxidation of polysulfide is diffusion controlled. The electrical charge in Coulombs produced by the oxidation of polysulfide is linearly related to the concentration of polysulfide within a certain range (≤0.5 M). Separators with a high porosity (large pore size) show high anodic currents, resulting in fast capacity degradation and low Coulombic efficiencies in Li-S cells. These results demonstrate this method can be used to correlate the polysulfide transport through separators with the separator structure and battery performance, therefore provide guidance for developing new separators for lithium-sulfur batteries.

  18. Measuring Cation Transport by Na,K- and H,K-ATPase in Xenopus Oocytes by Atomic Absorption Spectrophotometry: An Alternative to Radioisotope Assays

    PubMed Central

    Dürr, Katharina L.; Tavraz, Neslihan N.; Spiller, Susan; Friedrich, Thomas

    2013-01-01

    Whereas cation transport by the electrogenic membrane transporter Na+,K+-ATPase can be measured by electrophysiology, the electroneutrally operating gastric H+,K+-ATPase is more difficult to investigate. Many transport assays utilize radioisotopes to achieve a sufficient signal-to-noise ratio, however, the necessary security measures impose severe restrictions regarding human exposure or assay design. Furthermore, ion transport across cell membranes is critically influenced by the membrane potential, which is not straightforwardly controlled in cell culture or in proteoliposome preparations. Here, we make use of the outstanding sensitivity of atomic absorption spectrophotometry (AAS) towards trace amounts of chemical elements to measure Rb+ or Li+ transport by Na+,K+- or gastric H+,K+-ATPase in single cells. Using Xenopus oocytes as expression system, we determine the amount of Rb+ (Li+) transported into the cells by measuring samples of single-oocyte homogenates in an AAS device equipped with a transversely heated graphite atomizer (THGA) furnace, which is loaded from an autosampler. Since the background of unspecific Rb+ uptake into control oocytes or during application of ATPase-specific inhibitors is very small, it is possible to implement complex kinetic assay schemes involving a large number of experimental conditions simultaneously, or to compare the transport capacity and kinetics of site-specifically mutated transporters with high precision. Furthermore, since cation uptake is determined on single cells, the flux experiments can be carried out in combination with two-electrode voltage-clamping (TEVC) to achieve accurate control of the membrane potential and current. This allowed e.g. to quantitatively determine the 3Na+/2K+ transport stoichiometry of the Na+,K+-ATPase and enabled for the first time to investigate the voltage dependence of cation transport by the electroneutrally operating gastric H+,K+-ATPase. In principle, the assay is not limited to K+-transporting membrane proteins, but it may work equally well to address the activity of heavy or transition metal transporters, or uptake of chemical elements by endocytotic processes. PMID:23462593

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

    DOEpatents

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

    1999-01-01

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

  20. Heat transfer measurements on an incidence-tolerant low pressure turbine blade in a high speed linear cascade at low to moderate Reynolds numbers

    NASA Astrophysics Data System (ADS)

    Moualeu, Leolein Patrick Gouemeni

    Runway-independent aircraft are expected to be the future for short-haul flights by improving air transportation and reducing area congestion encountered in airports. The Vehicle Systems Program of NASA identified a Large Civil Tilt-Rotor, equipped with variable-speed power-turbine engines, as the best concept. At cruise altitude, the engine rotor-speed will be reduced by as much as the 50% of take-off speed. The large incidence variation in the low pressure turbine associated with the change in speed can be detrimental to the engine performance. Low pressure turbine blades in cruise altitude are more predisposed to develop regions of boundary layer separation. Typical phenomenon such as impinging wakes on downstream blades and mainstream turbulences enhance the complexity of the flow in low pressure turbines. It is therefore important to be able to understand the flow behavior to accurately predict the losses. Research facilities are seldom able to experimentally reproduce low Reynolds numbers at relevant engine Mach number. Having large incidence swing as an additional parameter in the investigation of the boundary layer development, on a low pressure turbine blade, makes this topic unique and as a consequence requires a unique facility to conduct the experimental research. The compressible flow wind tunnel facility at the University of North Dakota had been updated to perform steady state experiments on a modular-cascade, designed to replicate a large variation of the incidence angles. The high speed and low Reynolds number facility maintained a sealed and closed loop configuration for each incidence angle. The updated facility is capable to produce experimental Reynolds numbers as low as 45,000 and as high as 570,000 at an exit Mach number of 0.72. Pressure and surface temperature measurements were performed at these low pressure turbine conditions. The present thesis investigates the boundary layer development on the surface of an Incidence-tolerant blade. The heat transfer approach is the method used to obtain knowledge of the state of the boundary layer on the surface of the blade. Pressure and temperature distributions are acquired for Reynolds numbers of 50,000, 66,000, 228,000, and 568,000 at an exit Mach number of 0.72, and Reynolds numbers of 228,000, and 568,000 at an exit Mach number of 0.35. These experimental flow conditions are conducted at different flow inlet angles of 40°, 34.2°, 28°, 18°, 8°, -2.6°, -12°, and -17°, and at two free-stream turbulence levels. Results of the analyses performed show that as the incidence angle decreases, a region of laminar separation bubble forms on the pressure surface and grows toward the trailing-edge. It is also noted that the position of the leading-edge moves as the incidence angle varies. A transitional flow is observed on both the pressure and suction surfaces, mainly at the two highest incidence angles, for the high turbulence case. This investigation also reveals that the Stanton number increases as the mainstream turbulence increases, and that the Stanton number at the leading-edge increases as the Reynolds number decreases, as it is documented in the literature.

  1. Static and dynamic pressure measurements on a NACA 0012 airfoil in the Ames High Reynolds Number Facility

    NASA Technical Reports Server (NTRS)

    Mcdevitt, J. B.; Okuno, A. F.

    1985-01-01

    The supercritical flows at high subsonic speeds over a NACA 0012 airfoil were studied to acquire aerodynamic data suitable for evaluating numerical-flow codes. The measurements consisted primarily of static and dynamic pressures on the airfoil and test-channel walls. Shadowgraphs were also taken of the flow field near the airfoil. The tests were performed at free-stream Mach numbers from approximately 0.7 to 0.8, at angles of attack sufficient to include the onset of buffet, and at Reynolds numbers from 1 million to 14 million. A test action was designed specifically to obtain two-dimensional airfoil data with a minimum of wall interference effects. Boundary-layer suction panels were used to minimize sidewall interference effects. Flexible upper and lower walls allow test-channel area-ruling to nullify Mach number changes induced by the mass removal, to correct for longitudinal boundary-layer growth, and to provide contouring compatible with the streamlines of the model in free air.

  2. Quantitative measurement of intracellular transport of nanocarriers by spatio-temporal image correlation spectroscopy

    NASA Astrophysics Data System (ADS)

    Coppola, S.; Pozzi, D.; Candeloro De Sanctis, S.; Digman, M. A.; Gratton, E.; Caracciolo, G.

    2013-03-01

    Spatio-temporal image correlation spectroscopy (STICS) is a powerful technique for assessing the nature of particle motion in complex systems although it has been rarely used to investigate the intracellular dynamics of nanocarriers so far. Here we introduce a method for characterizing the mode of motion of nanocarriers and for quantifying their transport parameters on different length scales from single-cell to subcellular level. Using this strategy we were able to study the mechanisms responsible for the intracellular transport of DOTAP-DOPC/DNA (DOTAP: 1,2-dioleoyl-3-trimethylammonium-propane; DOPC: dioleoylphosphocholine) and DC-Chol-DOPE/DNA (DC-Chol: 3?-[N-(N,N-dimethylaminoethane)-carbamoyl] cholesterol; DOPE: dioleoylphosphatidylethanolamine) lipoplexes in CHO-K1 (CHO: Chinese hamster ovary) live cells. Measurement of both diffusion coefficients and velocity vectors (magnitude and direction) averaged over regions of the cell revealed the presence of distinct modes of motion. Lipoplexes diffused slowly on the cell surface (diffusion coefficient: D ? 0.003 ?m2 s-1). In the cytosol, the lipoplexes motion was characterized by active transport with average velocity v ? 0.03 ?m2 s-1 and random motion. The method permitted us to generate an intracellular transport map showing several regions of concerted motion of lipoplexes.

  3. Electron transport measurement of graphene under one-dimensional local strain

    NASA Astrophysics Data System (ADS)

    Kanda, A.; Tomori, H.; Nukui, Y.; Toyota, Y.; Karube, H.; Nihei, S.; Ootuka, Y.; Tsukagoshi, K.; Hayashi, M.; Yoshioka, H.

    2012-02-01

    Introducing a nonuniform strain is a promising technique for controlling electron transport in graphene. Theories have predicted the formation of band gaps with properly designed strain; however, reports on experimental transport properties of strained graphene are quite limited. In this presentation, we report the measurement of electron transport in graphene under one-dimensional local strain. The local strain was introduced by inserting a one-dimensional dielectric nanorod between a graphene film and its substrate, using a technique reported in [1]. We found that the conductivity across the strained region decreases around the Dirac point in comparison with the unstrained graphene attached to the substrate, although the mobility far from the Dirac point is almost unchanged. The results cannot be explained by the change of the capacitance between the graphene film and the gate electrode, indicating that the strain affects the electron transport. The experimental results on strained and unstrained graphene devices from the same graphene film as well as the numerical results will be discussed. [4pt] [1] H. Tomori et al., Appl. Phys. Express 4, 075102 (2011).

  4. Electron density and transport in top-gated graphene nanoribbon devices: First-principles Green function algorithms for systems containing a large number of atoms

    NASA Astrophysics Data System (ADS)

    Areshkin, Denis A.; Nikolić, Branislav K.

    2010-04-01

    The recent fabrication of graphene nanoribbon (GNR) field-effect transistors poses a challenge for first-principles modeling of carbon nanoelectronics due to many thousand atoms present in the device. The state of the art quantum transport algorithms, based on the nonequilibrium Green function formalism combined with the density-functional theory (NEGF-DFT), were originally developed to calculate self-consistent electron density in equilibrium and at finite bias voltage (as a prerequisite to obtain conductance or current-voltage characteristics, respectively) for small molecules attached to metallic electrodes where only a few hundred atoms are typically simulated. Here we introduce combination of two numerically efficient algorithms which make it possible to extend the NEGF-DFT framework to device simulations involving large number of atoms. Our first algorithm offers an alternative to the usual evaluation of the equilibrium part of electron density via numerical contour integration of the retarded Green function in the upper complex half-plane. It is based on the replacement of the Fermi function f(E) with an analytic function f˜(E) coinciding with f(E) inside the integration range along the real axis, but decaying exponentially in the upper complex half-plane. Although f˜(E) has infinite number of poles, whose positions and residues are determined analytically, only a finite number of those poles have non-negligible residues. We also discuss how this algorithm can be extended to compute the nonequilibrium contribution to electron density, thereby evading cumbersome real-axis integration (within the bias voltage window) of NEGFs which is very difficult to converge for systems with large number of atoms while maintaining current conservation. Our second algorithm combines the recursive formulas with the geometrical partitioning of an arbitrary multiterminal device into nonuniform segments in order to reduce the computational complexity of the retarded Green function evaluation by extracting only its submatrices required for electron density and transmission function. We illustrate fusion of these two algorithms into the NEGF-DFT-type code by computing charge transfer, charge redistribution and conductance in zigzag- GNR∣variable -width-armchair- GNR∣zigzag -GNR two-terminal device covered with a gate electrode made of graphene layer as well. The total number of carbon and edge-passivating hydrogen atoms within the simulated central region of this device is ≃7000 . Our self-consistent modeling of the gate voltage effect suggests that rather large gate voltage ≃3eV might be required to shift the band gap of the proposed AGNR interconnect and switch the transport from insulating into the regime of a single open conducting channel.

  5. Optimal two-qubit tomography based on local and global measurements: Maximal robustness against errors as described by condition numbers

    NASA Astrophysics Data System (ADS)

    Miranowicz, Adam; Bartkiewicz, Karol; Peřina, Jan; Koashi, Masato; Imoto, Nobuyuki; Nori, Franco

    2014-12-01

    We present an error analysis of various tomographic protocols based on the linear inversion for the reconstruction of an unknown two-qubit state. We solve the problem of finding a tomographic protocol which is the most robust against errors in terms of the lowest value (i.e., equal to 1) of a condition number, as required by the Gastinel-Kahan theorem. In contrast, standard tomographic protocols, including those based on mutually unbiased bases, are nonoptimal for determining all the 16 elements of an unknown two-qubit density matrix. Our method is based on the measurements of the 16 generalized Pauli operators, where twelve of them can be locally measured, and the other four require nonlocal Bell measurements. Our method corresponds to selectively measuring, one by one, all the real and imaginary elements of an unknown two-qubit density matrix. We describe two experimentally feasible setups of this protocol for the optimal reconstruction of two photons in an unknown polarization state using conventional detectors and linear-optical elements. Moreover, we define the operators for the optimal reconstruction of the states of multiqubit or multilevel (qudit) systems.

  6. A strain measurement model using a limited number of sensors for steel beam structures subjected to uncertain loadings

    NASA Astrophysics Data System (ADS)

    Oh, Byung Kwan; Hwang, Jin Woo; Lee, Ji Hoon; Kim, Yousok; Park, Hyo Seon

    2015-11-01

    The maximum stress of a structural member has been extensively adopted as a safety assessment indicator in structural health monitoring. Due to construction errors in the field and changes in the loading conditions during or after construction, it is impractical to accurately predict the location and magnitude of the maximum strain of a member a priori. To avoid the dependency of strain sensing methods on information of the structural and loading conditions, this paper proposes a strain distribution measurement model for steel beam structures subjected to uncertain loadings with uncertainties in magnitudes and shapes. With strains measured from a limited number of sensors, a general form equation of the strain distribution is determined for the estimation of the strain distribution. The performance of the strain distribution measurement model is verified by comparing estimated strain values from the proposed method and measured strains directly from fiber Bragg grating sensors or electrical strain gauges during static loading tests on single- and multi-span beam structures.

  7. On measurements and their quality. Paper 4: verbal anchors and the number of response options in rating scales.

    PubMed

    Beckstead, Jason W

    2014-05-01

    This is the last in a short series of papers on measurement theory and practice with particular relevance to intervention research in nursing, midwifery, and healthcare. Understanding how it is that people respond to the questions posed by researchers is fundamental to progress in the social and health sciences. For decades methodologists in psychology, marketing, education, and survey research have studied this issue. In this paper I review this diverse empirical literature to synthesize basic principles for creating rating scales which can reduce measurement error and increase the quality of resulting data. After introducing a theoretical framework known as the cognitive aspects of survey methods (CASM), I review the fundamentals of psychological scaling theory and discuss how it has been used to study the meanings of verbal response options and provide an illustration of how the quality of measurements may be influenced by our choice of the verbal phrases we present as response options. Next, I review the research on the optimal number of response options to use in various measurement situations and how verbal and numeric anchors can combine to influence data quality. Finally, I summarize the issues covered and present recommendations for best practice when creating and using rating scales in research. PMID:24125584

  8. Optical Emission Measurements of Electron Temperatures and Metastable Number Densities in a DC/RF Magnetically Confined Xe Plasma

    NASA Astrophysics Data System (ADS)

    Donnelly, Vincent M.; Baele, Pierre; Raitses, Yevgeny

    2011-10-01

    We report optical emission studies of a Penning type RF/DC discharge in 0.27 mTorr Xe plus traces of other rare gases. Emissions from selected Paschen 2p levels of Xe and trace Ne, Ar, and Kr were used to determine electron temperature (Te) and metastable number densities. Measurements were made as a function of distance from the center of the discharge chamber at several magnetic field strengths. Emission was viewed along a line-of-sight axis parallel or perpendicular to the axis of the magnets and 2 MHz RF inductively-coupled plasma source. Te values were 1- 3 eV, depending on the magnetic field, and were generally in good agreement with Langmuir probe measurements at 35 and 150 Gauss. Rare gas metastable number densities were derived from emission intensities from levels that were excited largely by electron impact from the ground state (e.g. Xe 2p3) , 1s5 (e.g. Xe 2p6) or 1s3 (e.g. Xe 2p4) . The peak fraction of Xe 1s5 varied from 0.005 at 435 Gauss to 0.001 at 35 Gauss. Intense Xe+ emission down the center of the discharge at high magnetic fields indicates a second population of high energy electrons. Performed at Princeton Plasma Physics Laboratory. Supported by the Department of Energy.

  9. Characteristics of submicron aerosol number size distribution and new particle formation events measured in Seoul, Korea, during 2004-2012

    NASA Astrophysics Data System (ADS)

    Park, Minsu; Yum, Seong Soo; Kim, Jong Hwan

    2015-02-01

    The diurnal and seasonal characteristics of the submicron aerosol size distribution measured in Seoul for a long term (2004-2012) were analyzed. The average diurnal variation of aerosol number size distribution showed a single modal distribution but the modal diameter varied around 35 nm and the total aerosol concentration varied diurnally with the maximum during the rush hour. To identify the dominant patterns of the diurnal variation of aerosol number size distribution, the cyclostationary empirical orthogonal function (CSEOF) method was employed. The first CSEOF mode revealed the dominant diurnal pattern that represented an urban life pattern. The principal component (PC) values of the first CSEOF mode showed clear seasonal variation. The PC values were the largest in winter months due to winter monsoon that brought polluted air masses from China, and larger traffic emission amount during the winter season. New particle formation (NPF) events were found to occur on 12.3% of the total measurement days in Seoul when classified with a subjective method. NPF frequency varied seasonally, with the maximum in spring. The second CSEOF mode was found to represent NPF events. A way to identify NPF event days by the CSEOF method was proposed and generally performed well but with some exceptions. The favorable conditions for NPF events in Seoul were found to be low RH, low condensation sink, and low cloud cover, which is consistent with some previous studies. Lastly, the relative contribution of NPF to ultrafine aerosol in Seoul was estimated to be ~32%.

  10. First Measurements of Neutral Atmospheric Cluster and 12 nm Particle Number Size Distributions During Nucleation Events

    SciTech Connect

    Jiang, J.; Kuang, C.; Zhao, J.; Chen, M.; Eisele, F. L.; Scheckman, J.; Williams, B. J.; McMurry, P. H.

    2011-02-01

    Recent observations throughout the atmosphere have shown that nucleation occurs frequently (Kulmala et al. 2004). Modeling studies and observations have shown that nucleated particles contribute significantly to concentrations of cloud condensation nuclei (Spracklen et al. 2008), thereby affecting climate (IPCC 2007). Size-resolved measurements extending down to molecular dimensions can provide information on processes that lead to nucleation and would enable development and verification of theories for particle nucleation and growth in the atmosphere and other aerosol systems. This article describes measurements of the complete number size distribution, spanning the size range from vapor molecules and molecular clusters to submicrometer particles, during atmospheric nucleation events. The measurements used two new instruments, the cluster chemical ionization mass spectrometer (Cluster CIMS) and the DEG SMPS. The Cluster CIMS measures neutral molecular clusters from 50 to 900 amu. The DEG SMPS is a scanning mobility particle spectrometer (SMPS) equipped with a diethylene glycol (DEG)-based condensation particle counter (CPC) capable of 1.1 nm mobility diameter particle detection, and overlapping the sizes detected by the Cluster CIMS (Iida et al. 2009; Jiang et al. 2011). The Cluster CIMS distinguishes neutral clusters from ions formed by ion-induced clustering by varying the reaction time for ions with the sampled air (Zhao et al. 2010). It distinguishes clusters from high molecular weight gases by measuring the incremental signal at a specified mass detected during nucleation events. The clusters that were measured in this study contain sulfuric acid, which is known to participate in atmospheric nucleation (Kuang et al. 2008).

  11. Compensation of the exhaust gas transport dynamics for accurate instantaneous emission measurements.

    PubMed

    Ajtay, Delia; Weilenmann, Martin

    2004-10-01

    Instantaneous emission models of vehicles describe the amount of emitted pollutants as a function of the driving state of the car. Emission measurements of chassis dynamometer tests with high time resolution are necessary for the development of such models. However, the dynamics of gas transport in both the exhaust system of the car and the measurement line last significantly longer than 1 s. In a simplified approach, the transport dynamics can be divided into two parts: a perfect time delay, corresponding to a piston-like transport of the exhaust gas, and a dynamic part, corresponding to the mixing of gases by turbulence along the way. This determines the occurrence of emission peaks that are longer in time and lower in height at the analyzer than they actually are in the vehicle at their location of formation. It is shown here how the sharp emission signals at their location of formation can be reconstructed from the flattened emission signals recorded at the analyzer by using signal theory approaches. A comparison between the reconstructions quality when using the raw or the dilution analyzer system is also given. PMID:15506210

  12. First Measurements of Edge Transport Driven by the Shoelace Antenna on Alcator C-Mod

    NASA Astrophysics Data System (ADS)

    Golfinopoulos, T.; Labombard, B.; Parker, R. R.; Burke, W. M.; Hughes, J. W.; Brunner, D. F.; Davis, E. M.; Ennever, P. C.; Granetz, R. S.; Greenwald, M. J.; Irby, J. H.; Leccacorvi, R.; Marmar, E. S.; Parkin, W. C.; Porkolab, M.; Terry, J. L.; Vieira, R. F.; Wolfe, S. M.; Wukitch, S. J.; Alcator C-Mod Team

    2015-11-01

    The Shoelace antenna is a unique device designed to couple to the Quasi-Coherent Mode (QCM, k⊥ ~ 1 . 5 cm-1, 50 < f < 200 kHz) and Weakly-Coherent Mode (WCM, k⊥ ~ 1 . 5 cm-1, 200 < f < 500 kHz), continuous edge fluctuations that sustain high-performance confinement regimes by exhausting impurities. The antenna is used to explore whether modes like the QCM and WCM may be exploited to actively regulate edge transport. In initial experiments, the antenna excited a resonance at the QCM frequency and phase velocity, but transport measurements were unavailable. A subsequent redesign of the winding pitch allows the antenna to be field-aligned while mapping magnetically to the Mirror Langmuir Probe (MLP) on the last-closed flux surface. This has enabled the first measurements of edge transport induced by the antenna-driven fluctuation, which has been further enhanced by quadrupling the antenna source power. This work was supported by U.S. Department of Energy award DE-FC02-99ER54512, using Alcator C-Mod, a DOE SC User Facility.

  13. Measuring Phonon Mean Free Path Distributions by Probing Quasiballistic Phonon Transport in Grating Nanostructures.

    PubMed

    Zeng, Lingping; Collins, Kimberlee C; Hu, Yongjie; Luckyanova, Maria N; Maznev, Alexei A; Huberman, Samuel; Chiloyan, Vazrik; Zhou, Jiawei; Huang, Xiaopeng; Nelson, Keith A; Chen, Gang

    2015-01-01

    Heat conduction in semiconductors and dielectrics depends upon their phonon mean free paths that describe the average travelling distance between two consecutive phonon scattering events. Nondiffusive phonon transport is being exploited to extract phonon mean free path distributions. Here, we describe an implementation of a nanoscale thermal conductivity spectroscopy technique that allows for the study of mean free path distributions in optically absorbing materials with relatively simple fabrication and a straightforward analysis scheme. We pattern 1D metallic grating of various line widths but fixed gap size on sample surfaces. The metal lines serve as both heaters and thermometers in time-domain thermoreflectance measurements and simultaneously act as wire-grid polarizers that protect the underlying substrate from direct optical excitation and heating. We demonstrate the viability of this technique by studying length-dependent thermal conductivities of silicon at various temperatures. The thermal conductivities measured with different metal line widths are analyzed using suppression functions calculated from the Boltzmann transport equation to extract the phonon mean free path distributions with no calibration required. This table-top ultrafast thermal transport spectroscopy technique enables the study of mean free path spectra in a wide range of technologically important materials. PMID:26612032

  14. Measuring phonon mean free path distributions by probing quasiballistic phonon transport in grating nanostructures

    DOE PAGESBeta

    Zeng, Lingping; Collins, Kimberlee C.; Hu, Yongjie; Luckyanova, Maria N.; Maznev, Alexei A.; Huberman, Samuel; Chiloyan, Vazrik; Zhou, Jiawei; Huang, Xiaopeng; Nelson, Keith A.; et al

    2015-11-27

    Heat conduction in semiconductors and dielectrics depends upon their phonon mean free paths that describe the average travelling distance between two consecutive phonon scattering events. Nondiffusive phonon transport is being exploited to extract phonon mean free path distributions. Here, we describe an implementation of a nanoscale thermal conductivity spectroscopy technique that allows for the study of mean free path distributions in optically absorbing materials with relatively simple fabrication and a straightforward analysis scheme. We pattern 1D metallic grating of various line widths but fixed gap size on sample surfaces. The metal lines serve as both heaters and thermometers in time-domainmore » thermoreflectance measurements and simultaneously act as wiregrid polarizers that protect the underlying substrate from direct optical excitation and heating. We demonstrate the viability of this technique by studying length-dependent thermal conductivities of silicon at various temperatures. The thermal conductivities measured with different metal line widths are analyzed using suppression functions calculated from the Boltzmann transport equation to extract the phonon mean free path distributions with no calibration required. Furthermore, this table-top ultrafast thermal transport spectroscopy technique enables the study of mean free path spectra in a wide range of technologically important materials.« less

  15. Transport of mineral dust derived from airborne wind lidar measurements during SALTRACE

    NASA Astrophysics Data System (ADS)

    Chouza, Fernando; Reitebuch, Oliver; Groß, Silke; Rahm, Stephan; Freudenthaler, Volker; Toledano, Carlos; Weinzierl, Bernadett

    2015-04-01

    During the SALTRACE field experiment conducted between the 10 of June and the 15 of July 2013, the transport and properties of Saharan dust were characterized by a 2-µm Doppler wind lidar (DWL) deployed on the DLR Falcon 20 research aircraft. Unlike aerosol lidars, the DLW is able to simultaneously measure wind fields and -by means of an adequate calibration- aerosol optical properties, which is more adequate for aerosol transport studies. The retrieved horizontal and vertical wind speed provide a direct observation of dust long range transport mechanisms across the Atlantic (e.g. by the African easterly jet) from Western Africa to the Caribbean. Vertical wind observations revealed the structure of island induced lee waves in the Cape Verde and Barbados regions. A novel method for the calibration of DWLs based on simultaneous measurements with a ground-based aerosol lidar and sun photometer was developed. After being calibrated, the system is able to retrieve quantitative aerosol backscatter and extinction coefficients, which is usually not obtained from coherent lidars. Results from the validation with a ground-based aerosol lidar in Barbados and the CALIPSO satellite instrument will be discussed.

  16. Measuring Phonon Mean Free Path Distributions by Probing Quasiballistic Phonon Transport in Grating Nanostructures

    NASA Astrophysics Data System (ADS)

    Zeng, Lingping; Collins, Kimberlee C.; Hu, Yongjie; Luckyanova, Maria N.; Maznev, Alexei A.; Huberman, Samuel; Chiloyan, Vazrik; Zhou, Jiawei; Huang, Xiaopeng; Nelson, Keith A.; Chen, Gang

    2015-11-01

    Heat conduction in semiconductors and dielectrics depends upon their phonon mean free paths that describe the average travelling distance between two consecutive phonon scattering events. Nondiffusive phonon transport is being exploited to extract phonon mean free path distributions. Here, we describe an implementation of a nanoscale thermal conductivity spectroscopy technique that allows for the study of mean free path distributions in optically absorbing materials with relatively simple fabrication and a straightforward analysis scheme. We pattern 1D metallic grating of various line widths but fixed gap size on sample surfaces. The metal lines serve as both heaters and thermometers in time-domain thermoreflectance measurements and simultaneously act as wire-grid polarizers that protect the underlying substrate from direct optical excitation and heating. We demonstrate the viability of this technique by studying length-dependent thermal conductivities of silicon at various temperatures. The thermal conductivities measured with different metal line widths are analyzed using suppression functions calculated from the Boltzmann transport equation to extract the phonon mean free path distributions with no calibration required. This table-top ultrafast thermal transport spectroscopy technique enables the study of mean free path spectra in a wide range of technologically important materials.

  17. Measuring Phonon Mean Free Path Distributions by Probing Quasiballistic Phonon Transport in Grating Nanostructures

    PubMed Central

    Zeng, Lingping; Collins, Kimberlee C.; Hu, Yongjie; Luckyanova, Maria N.; Maznev, Alexei A.; Huberman, Samuel; Chiloyan, Vazrik; Zhou, Jiawei; Huang, Xiaopeng; Nelson, Keith A.; Chen, Gang

    2015-01-01

    Heat conduction in semiconductors and dielectrics depends upon their phonon mean free paths that describe the average travelling distance between two consecutive phonon scattering events. Nondiffusive phonon transport is being exploited to extract phonon mean free path distributions. Here, we describe an implementation of a nanoscale thermal conductivity spectroscopy technique that allows for the study of mean free path distributions in optically absorbing materials with relatively simple fabrication and a straightforward analysis scheme. We pattern 1D metallic grating of various line widths but fixed gap size on sample surfaces. The metal lines serve as both heaters and thermometers in time-domain thermoreflectance measurements and simultaneously act as wire-grid polarizers that protect the underlying substrate from direct optical excitation and heating. We demonstrate the viability of this technique by studying length-dependent thermal conductivities of silicon at various temperatures. The thermal conductivities measured with different metal line widths are analyzed using suppression functions calculated from the Boltzmann transport equation to extract the phonon mean free path distributions with no calibration required. This table-top ultrafast thermal transport spectroscopy technique enables the study of mean free path spectra in a wide range of technologically important materials. PMID:26612032

  18. Measuring phonon mean free path distributions by probing quasiballistic phonon transport in grating nanostructures

    SciTech Connect

    Zeng, Lingping; Collins, Kimberlee C.; Hu, Yongjie; Luckyanova, Maria N.; Maznev, Alexei A.; Huberman, Samuel; Chiloyan, Vazrik; Zhou, Jiawei; Huang, Xiaopeng; Nelson, Keith A.; Chen, Gang

    2015-11-27

    Heat conduction in semiconductors and dielectrics depends upon their phonon mean free paths that describe the average travelling distance between two consecutive phonon scattering events. Nondiffusive phonon transport is being exploited to extract phonon mean free path distributions. Here, we describe an implementation of a nanoscale thermal conductivity spectroscopy technique that allows for the study of mean free path distributions in optically absorbing materials with relatively simple fabrication and a straightforward analysis scheme. We pattern 1D metallic grating of various line widths but fixed gap size on sample surfaces. The metal lines serve as both heaters and thermometers in time-domain thermoreflectance measurements and simultaneously act as wiregrid polarizers that protect the underlying substrate from direct optical excitation and heating. We demonstrate the viability of this technique by studying length-dependent thermal conductivities of silicon at various temperatures. The thermal conductivities measured with different metal line widths are analyzed using suppression functions calculated from the Boltzmann transport equation to extract the phonon mean free path distributions with no calibration required. Furthermore, this table-top ultrafast thermal transport spectroscopy technique enables the study of mean free path spectra in a wide range of technologically important materials.

  19. Describing and compensating gas transport dynamics for accurate instantaneous emission measurement

    NASA Astrophysics Data System (ADS)

    Weilenmann, Martin; Soltic, Patrik; Ajtay, Delia

    Instantaneous emission measurements on chassis dynamometers and engine test benches are becoming increasingly usual for car-makers and for environmental emission factor measurement and calculation, since much more information about the formation conditions can be extracted than from the regulated bag measurements (integral values). The common exhaust gas analysers for the "regulated pollutants" (carbon monoxide, total hydrocarbons, nitrogen oxide, carbon dioxide) allow measurement at a rate of one to ten samples per second. This gives the impression of having after-the-catalyst emission information with that chronological precision. It has been shown in recent years, however, that beside the reaction time of the analysers, the dynamics of gas transport in both the exhaust system of the car and the measurement system last significantly longer than 1 s. This paper focuses on the compensation of all these dynamics convoluting the emission signals. Most analysers show linear and time-invariant reaction dynamics. Transport dynamics can basically be split into two phenomena: a pure time delay accounting for the transport of the gas downstream and a dynamic signal deformation since the gas is mixed by turbulence along the way. This causes emission peaks to occur which are smaller in height and longer in time at the sensors than they are after the catalyst. These dynamics can be modelled using differential equations. Both mixing dynamics and time delay are constant for modelling a raw gas analyser system, since the flow in that system is constant. In the exhaust system of the car, however, the parameters depend on the exhaust volume flow. For gasoline cars, the variation in overall transport time may be more than 6 s. It is shown in this paper how all these processes can be described by invertible mathematical models with the focus on the more complex case of the car's exhaust system. Inversion means that the sharp emission signal at the catalyst out location can be reconstructed from a flattened emission signal at the sensor. In this modelling, special focus is put on finding an easy parameterisation for different cars. The process of finding these compensators consists of first describing the process by differential equations of appropriate order and parameterising them, resulting in low pass systems. The following step of inverting these systems results automatically in high pass systems. These kinds of systems, however, amplify measurement noise, thus they need signal filters to smooth their output.

  20. Measuring charge transport in nanopatterned PbS colloidal quantum dots using charge sensing

    NASA Astrophysics Data System (ADS)

    Ray, Nirat; Staley, Neal E.; Wanger, Darcy D.; Bawendi, Moungi G.; Kastner, Marc A.

    2014-03-01

    Colloidal quantum dots (CQDs) can self-assemble from solution into close-packed arrays, where the motion of electrons is expected to be correlated due to long-range coulomb interactions. In order to study electron transport in these arrays, measurement of conductance around zero bias is required. Devices fabricated using CQDs, however, tend to be highly resistive (owing to large tunnel barriers from the organic ligands), and techniques to increase the conductance, such as annealing, often lead to large scale cracking. We nanopattern PbS CQDs, using electron beam lithography and a liftoff process, adjacent to a charge sensor. The patterning process helps to eliminate cracking, and improve packing of the dots. By performing a time resolved measurement of charge through the dots, using the sensor, we are able to measure conductance values as low as 10- 19 Ω - 1 with a voltage bias of just 100mV. Our technique also allows us to map out the current voltage characteristics, even at low temperatures where the current becomes immeasurably small. We present the first transport measurements, near zero bias, on nanopatterned PbS quantum dots.

  1. Airborne Measurements in Support of the NASA Atmospheric Carbon and Transport - America (ACT-America) Mission

    NASA Technical Reports Server (NTRS)

    Browell, Edward; Lauvaux, Thomas; McGill, Matt; Miles, Natasha; Obland, Michael; O'Dell, Chris; Yang, Melissa; Meadows, Byron; Davis, Ken; Barrick, John; Chen, Gao; Dobler, Jeremy; Fried, Alan; Lin, Bing; Nehrir, Amin; Sweeney, Colm

    2015-01-01

    NASA announced the research opportunity Earth Venture Suborbital -2 (EVS-2) mission in support of the NASA's science strategic goals and objectives in 2013. Penn State University, NASA Langley Research Center (LaRC), and other academic institutions, government agencies, and industrial companies together formulated and proposed the Atmospheric Carbon and Transport -America (ACT -America) suborbital mission, which was subsequently selected for implementation. The airborne measurements that are part of ACT-America will provide a unique set of remote and in-situ measurements of CO2 over North America at spatial and temporal scales not previously available to the science community and this will greatly enhance our understanding of the carbon cycle. ACT -America will consist of five airborne campaigns, covering all four seasons, to measure regional atmospheric carbon distributions and to evaluate the accuracy of atmospheric transport models used to assess carbon sinks and sources under fair and stormy weather conditions. This coordinated mission will measure atmospheric carbon in the three most important regions of the continental US carbon balance: Northeast, Midwest, and South. Data will be collected using 2 airborne platforms (NASA Wallops' C-130 and NASA Langley's B-200) with both in-situ and lidar instruments, along with instrumented ground towers and under flights of the Orbiting Carbon Observatory (OCO-2) satellite. This presentation provides an overview of the ACT-America instruments, with particular emphasis on the airborne CO2and backscatter lidars, and the, rationale, approach, and anticipated results from this mission.

  2. Viscous flow through slowly expanding or contracting porous walls with low seepage Reynolds number: a model for transport of biological fluids through vessels.

    PubMed

    Dinarvand, Saeed

    2011-10-01

    In this article, the problem of laminar, isothermal, incompressible and viscous flow in a rectangular domain bounded by two moving porous walls, which enable the fluid to enter or exit during successive expansions or contractions, is investigated. The governing non-linear equations and their associated boundary conditions are transformed into a highly non-linear ordinary differential equation. The series solution of the problem is obtained by utilising the homotopy perturbation method. Graphical results are presented to investigate the influence of the non-dimensional wall dilation rate and seepage Reynolds number (Re) on the velocity, normal pressure distribution and wall shear stress. Since the transport of biological fluids through contracting or expanding vessels is characterised by low seepage Res, the current study focuses on the viscous flow driven by small wall contractions and expansions of two weakly permeable walls. PMID:21347910

  3. Radicals and Reservoirs in the GMI Chemistry and Transport Model: Comparison to Measurements

    NASA Technical Reports Server (NTRS)

    Douglass, Anne R.; Stolarski, Richard S.; Strahan, Susan E.; Connell, Peter S.

    2004-01-01

    We have used a three-dimensional chemistry and transport model (CTM), developed under the Global Modeling Initiative (GMI), to carry out two simulations of the composition of the stratosphere under changing halogen loading for 1995 through 2030. The two simulations differ only in that one uses meteorological fields from a general circulation model while the other uses meteorological fields from a data assimilation system. A single year's winds and temperatures are repeated for each 36-year simulation. We compare results from these two simulations with an extensive collection of data from satellite and ground-based measurements for 1993-2000. Comparisons of simulated fields with observations of radical and reservoir species for some of the major ozone-destroying compounds are of similar quality for both simulations. Differences in the upper stratosphere, caused by transport of total reactive nitrogen and methane, impact the balance among the ozone loss processes and the sensitivity of the two simulations to the change in composition.

  4. Measurements of electron transport in foils irradiated with a picosecond time scale laser pulse.

    PubMed

    Brown, C R D; Hoarty, D J; James, S F; Swatton, D; Hughes, S J; Morton, J W; Guymer, T M; Hill, M P; Chapman, D A; Andrew, J E; Comley, A J; Shepherd, R; Dunn, J; Chen, H; Schneider, M; Brown, G; Beiersdorfer, P; Emig, J

    2011-05-01

    The heating of solid foils by a picosecond time scale laser pulse has been studied by using x-ray emission spectroscopy. The target material was plastic foil with a buried layer of a spectroscopic tracer material. The laser pulse length was either 0.5 or 2 ps, which resulted in a laser irradiance that varied over the range 10(16)-10(19) W/cm(2). Time-resolved measurements of the buried layer emission spectra using an ultrafast x-ray streak camera were used to infer the density and temperature conditions as a function of laser parameters and depth of the buried layer. Comparison of the data to different models of electron transport showed that they are consistent with a model of electron transport that predicts the bulk of the target heating is due to return currents. PMID:21635097

  5. Airborne lidar measurements of pollution transport in central and southern California during CalNEX 2010

    NASA Astrophysics Data System (ADS)

    Senff, C. J.; Alvarez, R. J., II; Hardesty, R.; Langford, A. O.; Banta, R. M.; Brewer, A.; Davies, F.; Sandberg, S.; Marchbanks, R.; Weickmann, A.

    2010-12-01

    During the CalNEX experiment from May through July 2010, we co-deployed NOAA’s airborne ozone and aerosol lidar TOPAZ and the University of Leeds scanning Doppler wind lidar on a Twin Otter aircraft. We flew a total of 46 missions over central and southern California, focusing primarily on the Los Angeles Basin and Sacramento areas. The downward-looking lidars provided highly resolved measurements of ozone concentration, aerosol backscatter, and wind speed and direction in the boundary layer and lower free troposphere. We will use the airborne lidar data to characterize transport of ozone and aerosols on regional and local scales. In particular, we will focus on pollutant transport between air basins and the role of flow patterns in complex terrain, such as gap flows and orographic lifting and venting along mountain slopes, on pollutant distribution.

  6. Transport and Measurements of High-Current Electron Beams from X pinches

    SciTech Connect

    Agafonov, Alexey V.; Mingaleev, Albert R.; Romanova, Vera M.; Tarakanov, Vladimir P.; Shelkovenko, Tatiana A.; Pikuz, Sergey A.; Blesener, Isaac C.; Kusse, Bruce R.; Hammer, David A.

    2009-01-21

    Generation of electron beams is an unavoidable property of X-pinches and other pulsed-power-driven pinches of different geometry. Some issues concerning high-current electron beam transport from the X pinch to the diagnostic system and measurements of the beam current by Faraday cups with different geometry's are discussed. Of particular interest is the partially neutralized nature of the beam propagating from the X-pinch to a diagnostic system. Two scenarios of electron beam propagation from X-pinch to Faraday cup are analyzed by means of computer simulation using the PIC-code KARAT. The first is longitudinal neutralization by ions extracted from plasma at an output window of the X-pinch diode; the second is the beam transport through a plasma background between the diode and a diagnostic system.

  7. Aerosol Sources, Absorption, and Intercontinental Transport: Synergies Among Models, Remote Sensing, and Atmospheric Measurements

    NASA Technical Reports Server (NTRS)

    Chin, Mian; Chu, Allen; Levy, Robert; Remer, Lorraine; Kaufman, Yoram; Dubovik, Oleg; Holben, Brent; Eck, Tom; Anderson, Tad; Quinn, Patricia

    2004-01-01

    Aerosol climate forcing is one of the largest uncertainties in assessing the anthropogenic impact on the global climate system. This uncertainty arises from the poorly quantified aerosol sources, especially black carbon emissions, our limited knowledge of aerosol mixing state and optical properties, and the consequences of intercontinental transport of aerosols and their precursors. Here we use a global model GOCART to simulate atmospheric aerosols, including sulfate, black carbon, organic carbon, dust, and sea salt, from anthropogenic, .biomass burning, and natural sources. We compare the model calculated aerosol extinction and absorption with those quantities from the ground-based sun photometer measurements from AERON" at several different wavelengths and the field observations from ACE-Asia, and model calculated total aerosol optical depth and fine mode fractions with the MODIS satellite retrieval. We will also estimate the intercontinental transport of pollution and dust aerosols from their source regions to other areas in different seasons.

  8. Aerosol Sources, Absorption, and Intercontinental Transport: Synergies among Models, Remote Sensing, and Atmospheric Measurements

    NASA Technical Reports Server (NTRS)

    Chin, Mian; Ginoux, Paul; Dubovik, Oleg; Holben, Brent; Kaufman, Yoram; chu, Allen; Anderson, Tad; Quinn, Patricia

    2003-01-01

    Aerosol climate forcing is one of the largest uncertainties in assessing the anthropogenic impact on the global climate system. This uncertainty arises from the poorly quantified aerosol sources, especially black carbon emissions, our limited knowledge of aerosol mixing state and optical properties, and the consequences of intercontinental transport of aerosols and their precursors. Here we use a global model GOCART to simulate atmospheric aerosols, including sulfate, black carbon, organic carbon, dust, and sea salt, from anthropogenic, biomass burning, and natural sources. We compare the model calculated aerosol extinction and absorption with those quantities from the ground-based sun photometer measurements from AERONET at several different wavelengths and the field observations from ACE-Asia, and model calculated total aerosol optical depth and fine mode fractions with the MODIS satellite retrieval. We will also estimate the intercontinental transport of pollution and dust aerosols from their source regions to other areas in different seasons.

  9. Measurement of preheating due to radiation and nonlocal electron heat transport in laser-irradiated targets

    SciTech Connect

    Otani, K.; Shigemori, K.; Kadono, T.; Hironaka, Y.; Nakai, M.; Shiraga, H.; Azechi, H.; Mima, K.; Ozaki, N.; Kimura, T.; Miyanishi, K.; Kodama, R.; Sakaiya, T.; Sunahara, A.

    2010-03-15

    This paper reports an experimental study on preheating of laser-irradiated targets. We performed temperature measurements at the rear surface of laser-irradiated targets under conditions of two different laser wavelengths (0.35 or 0.53 mum) and several intensities (2x10{sup 13}-1x10{sup 14} W/cm{sup 2}) in order to verify an effect of radiation and nonlocal electron heat transport. The preheating temperature was evaluated by observing self-emission, reflectivity, and expansion velocity at the rear surface of planar polyimide foils. The experimental results show that the x-ray radiation is dominant for preheating for 0.35-mum laser irradiation, but contribution of nonlocal electron heat transport is not negligible for 0.53-mum laser irradiation conditions.

  10. Dust and pollution transport on global scales: Aerosol measurements and model predictions

    NASA Astrophysics Data System (ADS)

    Clarke, A. D.; Collins, W. G.; Rasch, P. J.; Kapustin, V. N.; Moore, K.; Howell, S.; Fuelberg, H. E.

    2001-12-01

    Vertical profiles of aerosol and gas phase species were measured on flights near Hawaii on April 9 and 10, 1999, during NASA's Pacific Exploratory Mission (PEM) Tropics B program. These measurements characterized aerosol microphysics, inferred chemistry, optical properties, and gases in several extensive dust and pollution plumes, also detected by satellites, which had 10,000-km trajectories back to sources in Asia. Size-resolved measurements indicative of aerosol sulfate, black carbon, dust, light scattering, and absorption allowed determination of their concentrations and contributions to column aerosol optical depth. A new Chemical Transport Model (CTM) that includes aerosol, meteorological fields, dynamics, gas and particle source emissions, a chemistry component (MATCH), and assimilated satellite data was used to predict aerosol and gas concentrations and the aerosol optical effects along our flight path. Flight measurements confirmed the "river-like" plume structures predicted by the CTM and showed close agreement with the predicted contributions of dust and sulfate to aerosol concentrations and optical properties for this global-scale transport path. Consistency between satellite, model and in situ assessment of aerosol optical depth was found, with noted exceptions, within ˜25%. Both observations and model results confirmed that this aerosol was being entrained into the marine boundary layer between Hawaii and California where it can be expected to modify the type and concentration of cloud condensation nuclei in ways that may alter properties of low-level clouds. These observations document the significance and complexity of long-range aerosol transport and highlight the potential of emerging CTM models to extend observational data and address related issues on global scales.

  11. High conversion of coal to transportation fuels for the future with low HC gas production. Progress report Number 10, January 1--March 31, 1995

    SciTech Connect

    Wiser, W.H.; Oblad, A.G.

    1995-04-01

    An objective of the Department of Energy in funding research in coal liquefaction, is to produce a synthetic crude from coal at a cost lower than $30.00 per barrel (Task A). A second objective is to produce a fuel which is low in aromatics, yet of sufficiently high octane number for use in the gasoline-burning transportation vehicles of today. To meet this second objective, research was proposed for conversion of the highly-aromatic liquid product from coal conversion to a product high in isoparaffins, which compounds in the gasoline range exhibit a high octane number (Task B). Experimental coal liquefaction studies conducted in a batch microreactor have demonstrated potential for high conversions of coal to liquids with low yields of hydrocarbon (HC) gases, hence small consumption of hydrogen in the primary liquefaction step. Ratios of liquids/HC gases as high as 30/1, at liquid yields as high as 82% of the coal by weight, have been achieved. The principal objective of this work is to examine how nearly one may approach these results in a continuous-flow system, at a size sufficient to evaluate the process concept for production of transportation fuels from coal. A continuous-flow reactor system is to be designed, constructed and operated. The system is to be computer-operated for process control and data logging, and is to be fully instrumented. The primary liquid products will be characterized by GC, FTIR, and GC/MS, to determine the types and quantities of the principal components produced under conditions of high liquids production with high ratios of liquids/HC gases. From these analyses, together with GC analyses of the HC gases, hydrogen consumption for the conversion to primary liquids will be calculated. Conversion of the aromatics of this liquid product to isoparaffins will be investigated. Results to date on both tasks are presented.

  12. On the importance of nearbed sediment flux measurements for estimating sediment transport in the surf zone

    NASA Astrophysics Data System (ADS)

    Ogston, Andrea S.; Sternberg, Richard W.

    1995-11-01

    Previous sediment studies in the surf zone typically have computed suspended sediment flux profiles by pairing a single current meter measurement at an elevation of 20 cm or more with measurements of suspended sediment concentration from sensor arrays located at 4-50 cm elevation. This note reports the results of a field experiment in which small impellor current meters were paired with OBS sensors at common elevations of 4, 9 and 19 cm from the bed and across the inner surf zone to obtain concurrent velocity and concentration profiles. The objectives of this experiment were to measure suspended sediment flux profiles within 20 cm of the seabed to determine the magnitude of flux very close to the seabed in comparison to measurements at higher elevation; and to evaluate the errors associated with estimating sediment flux using current meter measurements at only one elevation compared to flux estimates based on velocity profile measurements. Results show that the total sediment flux at z = 4 cm was greater than the flux higher in the water column ( z = 9 and 19 cm) by a factor of at least 2. The flux profiles computed using a single impellor current meter at z = 19 cm and OBS sensors at z = 4, 9 and 19 cm typically were between 0.5 and 2.0 times the flux profiles computed using paired instruments. In one case the estimate of flux direction from the single current meter data predicted transport in the wrong cross shore direction. These results highlight the importance of nearbed measurements of concentration and velocity in estimating sediment transport in the surf zone.

  13. Vertical Transport Processes for Inert and Scavenged Species: TRACE-A Measurements

    NASA Technical Reports Server (NTRS)

    Chatfield, Robert B.; Chan, K. Roland (Technical Monitor)

    1997-01-01

    The TRACE-A mission of the NASA DC-8 aircraft made a large-scale survey of the tropical and subtropical atmosphere in September and October of 1992. Both In-situ measurements of CO (G. Sachsen NASA Langley) and aerosol size (J. Browell group, NASA Langley) provide excellent data sets with which to constrain vertical transport by planetary boundary layer mixing and deep-cloud cumulus convection. Lidar profiles of aerosol-induced scattering and ozone (also by Bremen) are somewhat require more subtle interpretation as tracers, but the vertical information on layering largely compensates for these complexities. The reason this DC-8 dataset is so useful is that very large areas of biomass burning over Africa and South America provide surface sources of appropriate sizes with which to characterize vertical and horizontal motions; the major limitation of our source description is that biomass burning patterns move considerably every few days, and daily burning inventories are a matter of concurrent, intensive research. We use the Penn State / NCAR MM5 model in an assimilation mode on the synoptic and intercontinental scale, and assess the success it shows in vertical transport descriptions. We find that the general level of emissions suggested by the climatological approach (Will. Has, U. of Montana) appears to be approximately correct, possibly a bit low, for this October, 1992, time period. Vertical transport in planetary boundary layer mixing to 5.5 kin was observed and reproduced in our simulations. Furthermore we find evidence that Blackader "transilient" or matrix-transport scheme is needed, but may require some adaptation in our tracer model: CO seems to exhibit very high values at the top of the planetary boundary layer, a process that stretches the eddy-diffusion parameterization. We will report on progress in improving the deep convective transport of carbon monoxide: the Grail scheme as we used it at 100 kin resolution did not transport enough material to the upper troposphere. We expect to be able to attribute this to either parameterization reasons (inadequacy of this parameterization at the large 100km scale) or other reasons. Nevertheless, the qualitative nature of deep transport by clouds shows up well in the simulations. As for scavengable species, the simulations predict tens of micrograms per standard cubic meter of smoke aerosol in the boundary layer. In a straightforward illustration of our simple bulk-mass scavenging parameterization, to one or two micrograms per standard cubic meter of smoke aerosol in the free troposphere just above the source regions: very high concentrations for the free troposphere. We expect to report on comparisons of these predictions to a variety of observations.

  14. Temperature and number density measurement in non-uniform supersonic flowfields undergoing mixing using toluene PLIF thermometry

    NASA Astrophysics Data System (ADS)

    Gamba, Mirko; Miller, Victor A.; Mungal, M. Godfrey; Hanson, Ronald K.

    2015-08-01

    Single-excitation, dual-band-collection toluene planar laser-induced fluorescence (PLIF) is used to measure temperature and number density (or partial pressure) fields in non-uniform supersonic complex flows in the presence of mixing and compressibility. The study provides a quantitative evaluation of the technique in transverse jets in supersonic crossflow (JISCF). It is found that toluene PLIF is highly effective in visualizing the structure of supersonic flows and that temperature can be accurately inferred with acceptable signal-to-noise ratios (of order 30) even when mixing occurs. The technique was applied to several JISCFs that differ by jet fluid properties with resulting different structures. In the presence of compressibility and mixing, it is found that the PLIF signal is non-unique, a feature that is used to identify the mixing region of the transverse jet. Measurement errors due to camera registration errors have also been quantified. Because of the complexity of the flowfield, it is found that minute misalignment (<0.1 pixels) between the two PLIF images can introduce measurable errors on the order of tens of Kelvins and significant errors in temperature gradients.

  15. Gas Transport Parameters for Landfill Final Cover Soil: Measurements and Model Modification by Dry Bulk Density

    NASA Astrophysics Data System (ADS)

    Wickramarachchi, P. N.; Kawamoto, K.; Hamamoto, S.; Nagamori, M.; Moldrup, P.; Komatsu, T.

    2011-12-01

    Landfill sites have been emerging in greenhouse warming scenarios as a significant source of atmospheric methane (CH4). Until recently, landfill management strategies have mainly addressed the problem of preventing groundwater contamination and reduction of leachate generation. Being one of the largest sources of anthropogenic CH4 emission, the final cover system should also be designed for minimizing the greenhouse gases migration into the atmosphere or the areas surrounding the landfill while securing the hydraulic performance. Compared to the intensive research efforts on hydraulic performances of landfill final cover soil, few studies about gas transport characteristics of landfill cover soils have been done. However, recent soil-gas studies implied that the effects of soil physical properties such as bulk density (i.e., compaction level), soil particle size are key parameters to understand landfill gaseous performance. The gas exchange through the final cover soils is controlled by advective and diffusive gas transport. Air permeability (ka) governs the advective gas transport while the soil-gas diffusion coefficient (Dp) governs diffusive gas transport. In this study, the effects of compaction level and particle size fraction effects on ka and Dp for landfill final cover soil was investigated. The disturbed soil samples were taken from landfill final cover in Japan. A compaction tests were performed for the soil samples with two different size fractions (< 35 mm and < 2.0 mm). In the compaction tests at field water content , the soil samples were repacked into soil cores (i.d. 15-cm, length 12-cm, 2120 cm3) at two different compaction levels [(MP):2700 kN/m2 and (SP):600 kN/m2]. After the compaction tests, ka and Dp were measured and then samples were saturated and subsequently drained at different soil-water matric potential of 0.98, 2.94, 9.81, 1235 kPa and with air-dried and oven-dried conditions. Results showed that measured Dp and ka values for the coarser (< 35 mm) fraction became larger than finer (< 2 mm) for the given soil-air content. Further, compaction effort was much significant for ka than Dp for both fractions. We suggest this is because of compaction effects caused to create well-aligned macropore networks that are available for gas transport through the porous material. Then, the famous predictive models, the water induced linear reduction (WLR) model for Dp and the reference point law (RPL) model for ka were modified with reference point measurements (dry conditions) and model parameters and they correlated linearly to dry bulk density values for both fractions of landfill final cover soil.

  16. Noncontact temperature measurements in the microgravity fluids and transport phenomena discipline

    NASA Technical Reports Server (NTRS)

    Salzman, Jack

    1988-01-01

    The program of activities within the Microgravity Fluids and Transport Phenomena Discipline has been structured to enable the systematic pursuit of an increased understanding of low gravity fluid behavior/phenomena in a way which ensures that the results are appropriate to the widest range of applications. This structure is discussed and an overview of some of the activities which are underway is given. Of significance is the fact that in the majority of the current and planned activities, the measurement and, or control of the fluid temperature is a key experiment requirement. In addition, many of the experiments require that the temperature measurement be nonintrusive. A description of these requirements together with the current techniques which are being employed or under study to make these measurements is also discussed.

  17. H{alpha} measurements and neutral particle transport in Heliotron J

    SciTech Connect

    Kobayashi, S.; Yabutani, H.; Nakashima, Y.; Higashizono, Y.; Nagasaki, K.; Mizuuchi, T.; Okada, H.; Sano, F.; Cappa, A.; Kondo, K.; Nakamura, Y.; Suzuki, Y.

    2006-10-15

    A multichannel system of the H{alpha}-line emission detector is developed in order to investigate the neutral particle transport in the Heliotron J plasma. The application of a multianode photomultiplier tube to the filter measurement system enables us to observe the H{alpha} emission profile with 32 chords. The absolute calibration with a standard lamp is performed and the cross-talk between each of the adjoining channels is evaluated to be less than 6%, while the photomultiplier tube has a typical cross-talk of 3% in nominal value. The temporal and spatial profiles of the H{alpha} emission are measured in detail in the plasma breakdown by electron cyclotron heating (ECH). The H{alpha} emission profile in the ECH plasma is calculated by the Monte Carlo simulation using a three-dimensional mesh model. The fueling rates of the wall recycling and the gas puffing are estimated by means of the simulation and the measurement.

  18. Time-of-flight measurements and vertical transport in a high electron-mobility polymer

    NASA Astrophysics Data System (ADS)

    Blakesley, James C.; Schubert, Marcel; Steyrleuthner, Robert; Chen, Zhihua; Facchetti, Antonio; Neher, Dieter

    2011-10-01

    We investigate charge transport in a high-electron mobility polymer, poly(N,N-bis 2-octyldodecyl-naphthalene-1,4,5,8-bis dicarboximide-2,6-diyl-alt-5,5-2,2-bithiophene) [P(NDI2OD-T2), Polyera ActivInk™ N2200]. Time-of-flight measurements reveal electron mobilities approaching those measured in field-effect transistors, the highest ever recorded in a conjugated polymer using this technique. The modest temperature dependence and weak dispersion of the transients indicate low energetic disorder in this material. Steady-state electron-only current measurements reveal a barrier to injection of about 300 meV. We propose that this barrier is located within the P(NDI2OD-T2) film and arises from molecular orientation effects.

  19. Removing traffic emissions from CO2 time series measured at a tall tower using mobile measurements and transport modeling

    NASA Astrophysics Data System (ADS)

    Schmidt, Andres; Rella, Chris W.; Göckede, Mathias; Hanson, Chad; Yang, Zhenlin; Law, Beverly E.

    2014-11-01

    In recent years, measurements of atmospheric carbon dioxide with high precision and accuracy have become increasingly important for climate change research, in particular to inform terrestrial biosphere models. Anthropogenic carbon dioxide emissions from fossil fuel burning have long been recognized to contribute a significant portion of the carbon dioxide in the atmosphere. Here, we present an approach to remove the traffic related carbon dioxide emissions from mole fractions measured at a tall tower by using the corresponding carbon monoxide measurements in combination with footprint analyses and transport modeling. This technique improves the suitability of the CO2 data to be used in inverse modeling approaches of atmosphere-biosphere exchange that do not account for non-biotic portions of CO2. In our study region in Oregon, road traffic emissions are the biggest source of anthropogenic carbon dioxide and carbon monoxide. A three-day mobile campaign covering 1700 km of roads in northwestern Oregon was performed during summer of 2012 using a laser-based Cavity Ring-Down Spectrometer. The mobile measurements incorporated different roads including main highways, urban streets, and back-roads, largely within the typical footprint of a tall CO/CO2 observation tower in Oregon's Willamette Valley. For the first time, traffic related CO:CO2 emission ratios were measured directly at the sources during an on-road campaign under a variety of different driving conditions. An average emission ratio of 7.43 (±1.80) ppb CO per ppm CO2 was obtained for the study region and applied to separate the traffic related portion of CO2 from the mole fraction time series. The road traffic related portion of the CO2 mole fractions measured at the tower site reached maximum values ranging from 9.8 to 12 ppm, depending on the height above the surface, during summer 2012.

  20. PIV measurement of high-Reynolds-number homogeneous and isotropic turbulence in an enclosed flow apparatus with fan agitation

    NASA Astrophysics Data System (ADS)

    Dou, Zhongwang; Pecenak, Zachary K.; Cao, Lujie; Woodward, Scott H.; Liang, Zach; Meng, Hui

    2016-03-01

    Enclosed flow apparatuses with negligible mean flow are emerging as alternatives to wind tunnels for laboratory studies of homogeneous and isotropic turbulence (HIT) with or without aerosol particles, especially in experimental validation of Direct Numerical Simulation (DNS). It is desired that these flow apparatuses generate HIT at high Taylor-microscale Reynolds numbers ({{R}λ} ) and enable accurate measurement of turbulence parameters including kinetic energy dissipation rate and thereby {{R}λ} . We have designed an enclosed, fan-driven, highly symmetric truncated-icosahedron ‘soccer ball’ airflow apparatus that enables particle imaging velocimetry (PIV) and other whole-field flow measurement techniques. To minimize gravity effect on inertial particles and improve isotropy, we chose fans instead of synthetic jets as flow actuators. We developed explicit relations between {{R}λ} and physical as well as operational parameters of enclosed HIT chambers. To experimentally characterize turbulence in this near-zero-mean flow chamber, we devised a new two-scale PIV approach utilizing two independent PIV systems to obtain both high resolution and large field of view. Velocity measurement results show that turbulence in the apparatus achieved high homogeneity and isotropy in a large central region (48 mm diameter) of the chamber. From PIV-measured velocity fields, we obtained turbulence dissipation rates and thereby {{R}λ} by using the second-order velocity structure function. A maximum {{R}λ} of 384 was achieved. Furthermore, experiments confirmed that the root mean square (RMS) velocity increases linearly with fan speed, and {{R}λ} increases with the square root of fan speed. Characterizing turbulence in such apparatus paves the way for further investigation of particle dynamics in particle-laden homogeneous and isotropic turbulence.

  1. Global surface pressure measurements of static and dynamic stall on a wind turbine airfoil at low Reynolds number

    NASA Astrophysics Data System (ADS)

    Disotell, Kevin J.; Nikoueeyan, Pourya; Naughton, Jonathan W.; Gregory, James W.

    2016-05-01

    Recognizing the need for global surface measurement techniques to characterize the time-varying, three-dimensional loading encountered on rotating wind turbine blades, fast-responding pressure-sensitive paint (PSP) has been evaluated for resolving unsteady aerodynamic effects in incompressible flow. Results of a study aimed at demonstrating the laser-based, single-shot PSP technique on a low Reynolds number wind turbine airfoil in static and dynamic stall are reported. PSP was applied to the suction side of a Delft DU97-W-300 airfoil (maximum thickness-to-chord ratio of 30 %) at a chord Reynolds number of 225,000 in the University of Wyoming open-return wind tunnel. Static and dynamic stall behaviors are presented using instantaneous and phase-averaged global pressure maps. In particular, a three-dimensional pressure topology driven by a stall cell pattern is detected near the maximum lift condition on the steady airfoil. Trends in the PSP-measured pressure topology on the steady airfoil were confirmed using surface oil visualization. The dynamic stall case was characterized by a sinusoidal pitching motion with mean angle of 15.7°, amplitude of 11.2°, and reduced frequency of 0.106 based on semichord. PSP images were acquired at selected phase positions, capturing the breakdown of nominally two-dimensional flow near lift stall, development of post-stall suction near the trailing edge, and a highly three-dimensional topology as the flow reattaches. Structural patterns in the surface pressure topologies are considered from the analysis of the individual PSP snapshots, enabled by a laser-based excitation system that achieves sufficient signal-to-noise ratio in the single-shot images. The PSP results are found to be in general agreement with observations about the steady and unsteady stall characteristics expected for the airfoil.

  2. A Transport Analysis of In Situ Airborne Ozone Measurements from the 2011 DISCOVER-AQ Campaign

    NASA Astrophysics Data System (ADS)

    Arkinson, H. L.; Brent, L. C.; He, H.; Loughner, C.; Stehr, J. W.; Weinheimer, A. J.; Dickerson, R. R.

    2013-12-01

    Baltimore and Washington are currently designated as nonattainment areas with respect to the 2008 EPA National Ambient Air Quality Standard (NAAQS) for 8-hour Ozone (O3). Tropospheric O3 is the dominant component of summertime photochemical smog, and at high levels, has deleterious effects on human health, ecosystems, and materials. The University of Maryland (UMD) Regional Atmospheric Measurement Modeling and Prediction Program (RAMMPP) strives to improve understanding of air quality in the Mid-Atlantic States and to elucidate contributions of pollutants such as O3 from regional transport versus local sources through a combination of modeling and in situ measurements. The NASA Deriving Information on Surface Conditions from Column and Vertically Resolved Observations Relevant to Air Quality (DISCOVER-AQ) project investigates the connection between column measurements and surface conditions to explore the potential of remote sensing observations in diagnosing air quality at ground level where pollutants can affect human health. During the 2011 DISCOVER-AQ field campaign, in situ airborne measurements of trace gases and aerosols were performed along the Interstate 95 corridor between Baltimore and Washington from the NASA P3B aircraft. To augment this data and provide regional context, measurements of trace gases and aerosols were also performed by the RAMMPP Cessna 402B aircraft over nearby airports in Maryland and Virginia. This work presents an analysis of O3 measurements made by the Ultraviolet (UV) Photometric Ambient O3 Analyzer on the RAMMPP Cessna 402B and by the NCAR 4-Channel Chemiluminescence instrument on the NASA P3B. In this analysis, spatial and temporal patterns of O3 data are examined within the context of forward and backward trajectories calculated from 12-km North American Mesoscale (NAM) meteorological data using the NOAA Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) Model and from a high resolution Weather Research and Forecasting (WRF) model simulation in order to discern O3 resulting from regional transport versus O3 generated photochemically from local pollution sources. During the summer 2011 DISCOVER-AQ field campaign, both aircraft flew on eight overlapping dates. From the spirals performed on those flight days, over 15 cases have been identified where measurements of O3 were performed with one aircraft upwind of the other, based on forward and backward trajectory data. Analysis of these cases indicates that regional transport of O3 is enhanced up to 10% on average by local photochemical O3 production.

  3. Fringe pattern photobleaching, a new method for the measurement of transport coefficients of biological macromolecules.

    PubMed Central

    Davoust, J; Devaux, P F; Leger, L

    1982-01-01

    The conventional method of studying mass transport in membranes by spot photobleaching and then following the recovery of fluorescence has disadvantages. Among them, the need for a high density of fluorescent molecules, the measurement of the beam profile, and a knowledge of the photobleaching processes are of a crucial importance. The application of a planar fringe pattern of light both for the bleaching and the monitoring of the fluorescent molecules solves these three major difficulties. Brownian diffusion coefficients and flow velocities can be measured independently and are averaged over the whole fringe pattern volume. These transport coefficients are explored over the wide range of experimentally accessible distances (from an interfringe spacing 0.5-50 micron). The quantification of the mobile and immobile components is further simplified by scanning the fringe pattern and detecting only a modulated fluorescence recovery signal. The fringe pattern photobleaching method is particularly adapted to the measurements of diffusion coefficients and flow velocity of membrane components, as well as of cytoplasmic proteins. The theoretical results and the test experiments with fluorescent bovine serum albumin are described. PMID:6821332

  4. Apparatus for measurements of transport properties of thin films under sulfur atmosphere at moderate temperatures

    NASA Astrophysics Data System (ADS)

    Clamagirand, J. M.; Ares, J. R.; Diaz-Chao, P.; Pascual, A.; Ferrer, I. J.; Sánchez, C.

    2015-04-01

    An experimental system able to simultaneously measure the electrical resistance and the thermopower of metallic and semiconducting thin films (with thicknesses from ~nm to ~µm) under sulfur atmosphere from room temperature up to 400 °C and total pressures >0.5-1 mbar is designed and implemented. Calibration tests of the system were performed with palladium foils and films as well as p-type and n-type sulfide semiconducting films: iron disulfide and palladium monosulfide. Uncertainties of measured thermopower and resistance values are less than 10% and 5%, respectively. To check the capability of the system under sulfur atmosphere, in situ measurements of transport properties during sulfuration of palladium films were carried out. During the process, sulfur partial pressure and film temperature are accurately controlled. Apparatus may be used to determine the evolution of transport properties of different metal sulfides during their formation/decomposition processes, opening new pathways to investigate the thermoelectric properties of more complex thin film sulfides.

  5. Turbulent transport measurements in a cold model of GT-burner at realistic flow rates

    NASA Astrophysics Data System (ADS)

    Gobyzov, Oleg; Chikishev, Leonid; Lobasov, Alexey; Sharaborin, Dmitriy; Dulin, Vladimir; Bilsky, Artur; Tsatiashvili, Vakhtang; Avgustinovich, Valery; Markovich, Dmitriy

    2016-03-01

    In the present work simultaneous velocity field and passive admixture concentration field measurements at realistic flow-rates conditions in a non-reacting flow in a model of combustion chamber with an industrial mixing device are reported. In the experiments for safety reasons the real fuel (natural gas) was replaced with neon gas to simulate stratification in a strongly swirling flow. Measurements were performed by means of planar laser-induced fluorescence (PLIF) and particle image velocimetry technique (PIV) at Reynolds number, based on the mean flow rate and nozzle diameter, ≈300 000. Details on experimental technique, features of the experimental setup, images and data preprocessing procedures and results of performed measurements are given in the paper. In addition to the raw velocity and admixture concentration data in-depth evaluation approaches aimed for estimation of turbulent kinetic energy (TKE) components, assessment of turbulent Schmidt number and analysis of the gradient closure hypothesis from experimental data are presented in the paper.

  6. Thermal transport in CO2 laser irradiated fused silica: in situ measurements and analysis

    SciTech Connect

    Yang, S T; Matthews, M J; Elhadj, S; Draggoo, V G; Bisson, S E

    2009-07-07

    In situ spatial and temporal temperature measurements of pristine fused silica surfaces heated with a 10.6 {micro}m CO{sub 2} laser were obtained using an infrared radiation thermometer based on a Mercury Cadmium Telluride (MCT) camera. Laser spot sizes ranged from 250 {micro}m to 1000 {micro}m diameter with peak axial irradiance levels of 0.13 to 16 kW/cm{sup 2}. For temperatures below 2800K, the measured steady-state surface temperature is observed to rise linearly with both increasing beam size and incident laser irradiance. The effective thermal conductivity estimated over this range was approximately 2W/mK, in good agreement with classical calculations based on phonon heat capacities. Similarly, time-dependent temperature measurements up to 2000K yielded thermal diffusivity values which were close to reported values of 7 x 10{sup -7} m{sup 2}/s. Above {approx}2800K, the fused silica surface temperature asymptotically approaches 3100K as laser power is further increased, consistent with the onset of evaporative heat losses near the silica boiling point. These results show that in the laser heating regime studied here, the T{sup 3} temperature dependent thermal conductivity due to radiation transport can be neglected, but at temperatures above 2800K heat transport due to evaporation must be considered. The thermal transport in fused silica up to 2800K, over a range of conditions, can then be adequately described by a linear diffusive heat equation assuming constant thermal properties.

  7. Copy number variation in the ATP-binding cassette transporter ABCC6 gene and ABCC6 pseudogenes in patients with pseudoxanthoma elasticum

    PubMed Central

    Kringen, Marianne K; Stormo, Camilla; Berg, Jens Petter; Terry, Sharon F; Vocke, Christine M; Rizvi, Samar; Hendig, Doris; Piehler, Armin P

    2015-01-01

    Single mutations in the ATP-binding cassette transporter (ABCC6) gene (OMIM 603234) are known to cause the rare autosomal recessive disease pseudoxanthoma elasticum (PXE). Recently, we have found that copy number variations (CNVs) in pseudogenes of the ABCC6 gene are quite common. The aim of this study was to investigate the frequency and possible contribution of CNV in ABCC6 and its pseudogenes in PXE. Genomic DNA from 212 PXE individuals were examined for copy number by pyrosequencing and quantitative polymerase chain reaction (PCR) and compared with healthy individuals. The frequency of PXE individuals with any CNV was higher than in healthy individuals. The majority of variation comprised known and possibly new deletions in the ABCC6 gene and duplications of the ABCC6P1 and ABCC6P2 genes. ABCC6 deletions and ABCC6P2 duplications were not observed in 142 healthy individuals. In conclusion, by pyrosequencing and quantitative PCR, we were able to detect known and possibly new deletions in the ABCC6 gene that may have caused the PXE phenotype. Pyrosequencing may be used in PXE patients who have obtained incomplete genotype from conventional techniques. The frequency of ABCC6P2 pseudogene duplication was more common in PXE patients than healthy individuals and may affect the PXE phenotype. PMID:26029710

  8. Quantum transport measurement of few-layer WTe2 field effect devices

    NASA Astrophysics Data System (ADS)

    Chen, Jianhao; Liu, Xin; Tian, Shibing; Zhang, Chenglong; Jia, Shuang

    2015-03-01

    We have performed systematic quantum transport measurement on field effect devices fabricated from few-layer WTe2 single crystals. We found that the magnetoresistance of few-layer WTe2 could be very different from that of bulk samples, which may arise from the imbalance of electron and hole carriers in the samples. We shall discuss our findings in more details in light of recent progress in our experiment. This work is supported by National Natural Science Foundation of China (11374021 and 11327406); by China Ministry of Science and Technology under Contract # 2014CB920900 and 2013CB921900; and by the Young 1000-Talent Program of China.

  9. Temperature dependent spin transport properties of platinum inferred from spin Hall magnetoresistance measurements

    NASA Astrophysics Data System (ADS)

    Meyer, Sibylle; Althammer, Matthias; Geprägs, Stephan; Opel, Matthias; Gross, Rudolf; Goennenwein, Sebastian T. B.

    2014-06-01

    We study the temperature dependence of the spin Hall magnetoresistance (SMR) in yttrium iron garnet/platinum hybrid structures via magnetization orientation dependent magnetoresistance measurements. Our experiments show a decrease of the SMR magnitude with decreasing temperature. Using the sensitivity of the SMR to the spin transport properties of the normal metal, we interpret our data in terms of a decrease of the spin Hall angle in platinum from 0.11 at room temperature to 0.075 at 10 K, while the spin diffusion length and the spin mixing conductance of the ferrimagnetic insulator/normal metal interface remain almost constant.

  10. Direct, Absolute, and In Situ Measurement of Fast Electron Transport via Cherenkov Emission

    SciTech Connect

    Habara, Hideaki; Ohta, Kazuhide; Tanaka, Kazuo A.; Kumar, G. Ravindra; Krishnamurthy, M.; Kahaly, Subhendu; Mondal, Sudipta; Bhuyan, Manoj Kumar; Rajeev, R.; Zheng Jian

    2010-02-05

    We present direct measurements of the absolute energy distribution of relativistic electrons generated in intense, femtosecond laser interaction with a solid. Cherenkov emission radiated by these electrons in a novel prism target is spectrally dispersed to obtain yield and energy distribution of electrons simultaneously. A crucial advance is the observation of high density electron current as predicted by particle simulations and its transport as it happens inside the target. In addition, the strong sheath potential present at the rear side of the target is inferred from a comparison of the electron spectra derived from Cherenkov light observation with that from a magnet spectrometer.

  11. Temperature dependent spin transport properties of platinum inferred from spin Hall magnetoresistance measurements

    SciTech Connect

    Meyer, Sibylle Althammer, Matthias; Geprägs, Stephan; Opel, Matthias; Goennenwein, Sebastian T. B.; Gross, Rudolf

    2014-06-16

    We study the temperature dependence of the spin Hall magnetoresistance (SMR) in yttrium iron garnet/platinum hybrid structures via magnetization orientation dependent magnetoresistance measurements. Our experiments show a decrease of the SMR magnitude with decreasing temperature. Using the sensitivity of the SMR to the spin transport properties of the normal metal, we interpret our data in terms of a decrease of the spin Hall angle in platinum from 0.11 at room temperature to 0.075 at 10 K, while the spin diffusion length and the spin mixing conductance of the ferrimagnetic insulator/normal metal interface remain almost constant.

  12. Day-to-night transport in the Martian ionosphere: Implications from total electron content measurements

    NASA Astrophysics Data System (ADS)

    Cui, J.; Galand, M.; Yelle, R. V.; Wei, Y.; Zhang, S.-J.

    2015-03-01

    The nightside Martian ionosphere is thought to be contributed by day-to-night transport and electron precipitation, of which the former has not been well studied. In this work, we evaluate the role of day-to-night transport based on the total electron content (TEC) measurements made by the Mars Advanced Radar for Subsurface and Ionospheric Sounding on board Mars Express. This is accomplished by an examination of the variation of nightside TEC in the time domain rather than the traditional solar zenith angle domain. Our analyses here, being constrained to the Northern Hemisphere where the effects of crustal magnetic fields can be neglected, reveal that day-to-night transport serves as the dominant source for the nightside Martian ionosphere from terminator crossing up to time in darkness of ≈5.3 × 103 s, beyond which it is surpassed by electron precipitation. The observations are compared with predictions from a simplified time-dependent ionosphere model. We conclude that the solid body rotation of Mars is insufficient to account for the observed depletion of nightside TEC but the data could be reasonably reproduced by a zonal electron flow velocity of ≈1.9 km s-1.

  13. Gold nanoparticles grown inside carbon nanotubes: synthesis and electrical transport measurements

    PubMed Central

    2014-01-01

    The hybrid structures composed of gold nanoparticles and carbon nanotubes were prepared using porous alumina membranes as templates. Carbon nanotubes were synthesized inside the pores of these templates by the non-catalytic decomposition of acetylene. The inner cavity of the supported tubes was used as nanoreactors to grow gold particles by impregnation with a gold salt, followed by a calcination-reduction process. The samples were characterized by transmission electron microscopy and X-ray energy dispersion spectroscopy techniques. The resulting hybrid products are mainly encapsulated gold nanoparticles with different shapes and dimensions depending on the concentration of the gold precursor and the impregnation procedure. In order to understand the electronic transport mechanisms in these nanostructures, their conductance was measured as a function of temperature. The samples exhibit a ‘non-metallic’ temperature dependence where the dominant electron transport mechanism is 1D hopping. Depending on the impregnation procedure, the inclusion of gold nanoparticles inside the CNTs can introduce significant changes in the structure of the tubes and the mechanisms for electronic transport. The electrical resistance of these hybrid structures was monitored under different gas atmospheres at ambient pressure. Using this hybrid nanostructures, small amounts of acetylene and hydrogen were detected with an increased sensibility compared with pristine carbon nanotubes. Although the sensitivity of these hybrid nanostructures is rather low compared to alternative sensing elements, their response is remarkably fast under changing gas atmospheres. PMID:24910571

  14. Turbulent transport and length scale measurement experiments with comfined coaxial jets

    NASA Technical Reports Server (NTRS)

    Johnson, B. V.; Roback, R.

    1984-01-01

    A three phase experimental study of mixing downstream of swirling and nonswirling confined coaxial jets was conducted to obtain data for the evaluation and improvement of turbulent transport models currently employed in a variety of computational procedures. The present effort was directed toward the acquisition of length scale and dissipation rate data that provide more accurate inlet boundary conditions for the computational procedures and a data base to evaluate the turbulent transport models in the near jet region where recirculation does not occur, and the acquisition of mass and momentum turbulent transport data for a nonswirling flow condition with a blunt inner jet inlet configuration rather than the tapered inner jet inlet. A measurement technique, generally used to obtain approximate integral length and microscales of turbulence and dissipation rates, was computerized. Results showed the dissipation rate varied by 2 1/2 orders of magnitude across the inlet plane, by 2 orders of magnitude 51 mm from the inlet plane, and by 1 order of magnitude at 102 mm from the inlet plane for a nonswirling flow test conditions.

  15. Gold nanoparticles grown inside carbon nanotubes: synthesis and electrical transport measurements

    NASA Astrophysics Data System (ADS)

    Segura, Rodrigo A.; Contreras, Claudia; Henriquez, Ricardo; Häberle, Patricio; Acuña, José Javier S.; Adrian, Alvaro; Alvarez, Pedro; Hevia, Samuel A.

    2014-05-01

    The hybrid structures composed of gold nanoparticles and carbon nanotubes were prepared using porous alumina membranes as templates. Carbon nanotubes were synthesized inside the pores of these templates by the non-catalytic decomposition of acetylene. The inner cavity of the supported tubes was used as nanoreactors to grow gold particles by impregnation with a gold salt, followed by a calcination-reduction process. The samples were characterized by transmission electron microscopy and X-ray energy dispersion spectroscopy techniques. The resulting hybrid products are mainly encapsulated gold nanoparticles with different shapes and dimensions depending on the concentration of the gold precursor and the impregnation procedure. In order to understand the electronic transport mechanisms in these nanostructures, their conductance was measured as a function of temperature. The samples exhibit a `non-metallic' temperature dependence where the dominant electron transport mechanism is 1D hopping. Depending on the impregnation procedure, the inclusion of gold nanoparticles inside the CNTs can introduce significant changes in the structure of the tubes and the mechanisms for electronic transport. The electrical resistance of these hybrid structures was monitored under different gas atmospheres at ambient pressure. Using this hybrid nanostructures, small amounts of acetylene and hydrogen were detected with an increased sensibility compared with pristine carbon nanotubes. Although the sensitivity of these hybrid nanostructures is rather low compared to alternative sensing elements, their response is remarkably fast under changing gas atmospheres.

  16. Measurements of air pollution emission factors for marine transportation in SECA

    NASA Astrophysics Data System (ADS)

    Alföldy, B.; Lööv, J. B.; Lagler, F.; Mellqvist, J.; Berg, N.; Beecken, J.; Weststrate, H.; Duyzer, J.; Bencs, L.; Horemans, B.; Cavalli, F.; Putaud, J.-P.; Janssens-Maenhout, G.; Csordás, A. P.; Van Grieken, R.; Borowiak, A.; Hjorth, J.

    2013-07-01

    The chemical composition of the plumes of seagoing ships was measured during a two week long measurement campaign in the port of Rotterdam, Hoek van Holland The Netherlands, in September 2009. Altogether, 497 ships were monitored and a statistical evaluation of emission factors (g kg-1 fuel) was provided. The concerned main atmospheric components were SO2, NO2, NOx and the aerosol particle number. In addition, the elemental and water-soluble ionic composition of the emitted particulate matter was determined. Emission factors were expressed as a function of ship type, power and crankshaft rotational speed. The average SO2 emission factor was found to be roughly half of what is allowed in sulphur emission control areas (16 vs. 30 g kg-1 fuel), and exceedances of this limit were rarely registered. A significant linear relationship was observed between the SO2 and particle number emission factors. The intercept of the regression line, 4.8 × 1015 (kg fuel)-1, gives the average number of particles formed during the burning of 1 kg zero sulphur content fuel, while the slope, 2 × 1018, provides the average number of particles formed with 1 kg sulphur burnt with the fuel. Water-soluble ionic composition analysis of the aerosol samples from the plumes showed that ~144 g of particulate sulphate was emitted from 1 kg sulphur burnt with the fuel. The mass median diameter of sulphate particles estimated from the measurements was ~42 nm.

  17. Developing a Measure of Traffic Calming Associated with Elementary School Students’ Active Transport

    PubMed Central

    Nicholson, Lisa M.; Turner, Lindsey; Slater, Sandy J.; Abuzayd, Haytham; Chriqui, Jamie F.; Chaloupka, Frank

    2014-01-01

    The objective of this study is to develop a measure of traffic calming with nationally available GIS data from NAVTEQ and to validate the traffic calming index with the percentage of children reported by school administrators as walking or biking to school, using data from a nationally representative sample of elementary schools in 2006-2010. Specific models, with and without correlated errors, examined associations of objective GIS measures of the built environment, nationally available from NAVTEQ, with the latent construct of traffic calming. The best fit model for the latent traffic calming construct was determined to be a five factor model including objective measures of intersection density, count of medians/dividers, count of low mobility streets, count of roundabouts, and count of on-street parking availability, with no correlated errors among items. This construct also proved to be a good fit for the full measurement model when the outcome measure of percentage of students walking or biking to school was added to the model. The traffic calming measure was strongly, significantly, and positively correlated with the percentage of students reported as walking or biking to school. Applicability of results to public health and transportation policies and practices are discussed. PMID:25506255

  18. Development of vacuum ultraviolet absorption spectroscopy system for wide measurement range of number density using a dual-tube inductively coupled plasma light source

    SciTech Connect

    Kuwahara, Akira; Matsui, Makoto; Yamagiwa, Yoshiki

    2012-12-15

    A vacuum ultraviolet absorption spectroscopy system for a wide measurement range of atomic number densities is developed. Dual-tube inductively coupled plasma was used as a light source. The probe beam profile was optimized for the target number density range by changing the mass flow rate of the inner and outer tubes. This system was verified using cold xenon gas. As a result, the measurement number density range was extended from the conventional two orders to five orders of magnitude.

  19. Identifying fire plumes in the Arctic with tropospheric FTIR measurements and transport models

    NASA Astrophysics Data System (ADS)

    Viatte, C.; Strong, K.; Hannigan, J.; Nussbaumer, E.; Emmons, L.; Conway, S.; Paton-Walsh, C.; Hartley, J.; Benmergui, J.; Lin, J.

    2014-10-01

    We investigate Arctic tropospheric composition using ground-based Fourier Transform Infrared (FTIR) solar absorption spectra, recorded at the Polar Environment Atmospheric Research Laboratory (PEARL, Eureka, Nunavut, Canada, 80°5' N, 86°42' W) and at Thule (Greenland, 76°53' N, -68°74' W) from 2008 to 2012. The target species: carbon monoxide (CO), hydrogen cyanide (HCN), ethane (C2H6), acetylene (C2H2), formic acid (HCOOH), and formaldehyde (H2CO) are emitted by biomass burning and can be transported from mid-latitudes to the Arctic. By detecting simultaneous enhancements of three biomass burning tracers (HCN, CO, and C2H6), ten and eight fire events are identified at Eureka and Thule, respectively, within the five-year FTIR timeseries. Analyses of Hybrid Single Particle Lagrangian Integrated Trajectory Model (HYSPLIT) back-trajectories coupled with Moderate Resolution Imaging Spectroradiometer (MODIS) fire hot spot data, Stochastic Time-Inverted Lagrangian Transport model (STILT) footprints, and Ozone Monitoring Instrument (OMI) UV aerosol index maps are used to attribute burning source regions and travel time durations of the plumes. By taking into account the effect of aging of the smoke plumes, measured FTIR enhancement ratios were corrected to obtain emission ratios and equivalent emission factors. The means of emission factors for extratropical forest estimated with the two FTIR datasets are 0.39 ± 0.15 g kg-1 for HCN, 1.23 ± 0.49 g kg-1 for C2H6, 0.34 ± 0.16 g kg-1 for C2H2, 2.13 ± 0.92 g kg-1 for HCOOH, and 3.14 ± 1.28 g kg-1 for CH3OH. To improve our knowledge concerning the dynamical and chemical processes associated with Arctic pollution from fires, the two sets of FTIR measurements were compared to the Model for Ozone and Related chemical Tracers, version 4 (MOZART-4). Seasonal cycles and day-to-day variabilities were compared to assess the ability of the model to reproduce emissions from fires and their transport. Good agreement in winter confirms that transport is well implemented in the model. For C2H6, however, the lower wintertime concentration estimated by the model as compared to the FTIR observations highlight an underestimation of its emission. Results show that modelled and measured total columns are correlated (linear correlation coefficient r > 0.6 for all gases except for H2CO at Eureka and HCOOH at Thule), but suggest a~general underestimation of the concentrations in the model for all seven tropospheric species in the high Arctic.

  20. Identifying fire plumes in the Arctic with tropospheric FTIR measurements and transport models

    NASA Astrophysics Data System (ADS)

    Viatte, C.; Strong, K.; Hannigan, J.; Nussbaumer, E.; Emmons, L. K.; Conway, S.; Paton-Walsh, C.; Hartley, J.; Benmergui, J.; Lin, J.

    2015-03-01

    We investigate Arctic tropospheric composition using ground-based Fourier transform infrared (FTIR) solar absorption spectra, recorded at the Polar Environment Atmospheric Research Laboratory (PEARL, Eureka, Nunavut, Canada, 80°05' N, 86°42' W) and at Thule (Greenland, 76°53' N, -68°74' W) from 2008 to 2012. The target species, carbon monoxide (CO), hydrogen cyanide (HCN), ethane (C2H6), acetylene (C2H2), formic acid (HCOOH), and formaldehyde (H2CO) are emitted by biomass burning and can be transported from mid-latitudes to the Arctic. By detecting simultaneous enhancements of three biomass burning tracers (HCN, CO, and C2H6), ten and eight fire events are identified at Eureka and Thule, respectively, within the 5-year FTIR time series. Analyses of Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model back-trajectories coupled with Moderate Resolution Imaging Spectroradiometer (MODIS) fire hotspot data, Stochastic Time-Inverted Lagrangian Transport (STILT) model footprints, and Ozone Monitoring Instrument (OMI) UV aerosol index maps, are used to attribute burning source regions and travel time durations of the plumes. By taking into account the effect of aging of the smoke plumes, measured FTIR enhancement ratios were corrected to obtain emission ratios and equivalent emission factors. The means of emission factors for extratropical forest estimated with the two FTIR data sets are 0.40 ± 0.21 g kg-1 for HCN, 1.24 ± 0.71 g kg-1 for C2H6, 0.34 ± 0.21 g kg-1 for C2H2, and 2.92 ± 1.30 g kg-1 for HCOOH. The emission factor for CH3OH estimated at Eureka is 3.44 ± 1.68 g kg-1. To improve our knowledge concerning the dynamical and chemical processes associated with Arctic pollution from fires, the two sets of FTIR measurements were compared to the Model for OZone And Related chemical Tracers, version 4 (MOZART-4). Seasonal cycles and day-to-day variabilities were compared to assess the ability of the model to reproduce emissions from fires and their transport. Good agreement in winter confirms that transport is well implemented in the model. For C2H6, however, the lower wintertime concentration estimated by the model as compared to the FTIR observations highlights an underestimation of its emission. Results show that modeled and measured total columns are correlated (linear correlation coefficient r > 0.6 for all gases except for H2CO at Eureka and HCOOH at Thule), but suggest a general underestimation of the concentrations in the model for all seven tropospheric species in the high Arctic.

  1. Photocharge transport and recombination measurements in amorphous silicon films and solar cells by photoconductive frequency mixing: Annual subcontract report, 20 April 1998--19 April 1999

    SciTech Connect

    Braunstein, R.; Kattwinkel, A.; Liebe, J.; Sun, G.

    2000-02-28

    In the present phase of the program, the transport parameters of a number of amorphous semiconductors prepared by a number of techniques were determined by the photoconductive frequency mixing technique. This technique enabled the authors to determine the drift mobility, md, and the photomixing lifetime, t. The technique is based on the idea of heterodyne detection for photoconductors. When two similarly polarized monochromatic optical beams of slightly different frequencies are incident upon a photoconductor, the generation rate of electron-hole pairs will produce a photocurrent, when a dc-bias is applied, which will contain components resulting from the square of the sum of the individual incident fields. Consequently, a photocurrent will be produced, which will consist of a direct current and a microwave current corresponding to the beat frequency. These two currents allow a separate determination of the drift mobility and the photomixing lifetime of the photogenerated carriers. In the present work, the longitudinal modes of a He-Ne laser were employed to generate a beat frequency of 252 MHz; all the measurements were performed at this frequency for the data indicated in the accompanying figures. The following topics were explored: Measurements of the charge transport parameters of homogeneous a-SiGe:H alloys produced by NREL employing the hot-wire technique; The change in the charge transport parameters in the transition from hydrogenated amorphous silicon to microcrystalline silicon for material produced by NREL and MVSystems; The improvement in instrumentation of the photomixing measurements; Measurements of the hydrostatic dependency of the transport parameters of amorphous silicon; and Preliminary photomixing measurements on p-i-n devices.

  2. MIDWEST INTERSTATE SULFUR TRANSFORMATION AND TRANSPORT PROJECT: AERIAL MEASUREMENTS OF URBAN AND POWER PLANT PLUMES, SUMMER 1974

    EPA Science Inventory

    A portion of the research activities of the Midwest Interstate Sulfur Transformation and Transport Project (Project MISTT) during the summer of 1974 is documented. Using a light plane equipped with instruments for measuring air pollutants and meteorological parameters, investigat...

  3. Measurement of the Critical Deposition Velocity in Slurry Transport through a Horizontal Pipe

    SciTech Connect

    Erian, Fadel F.; Furfari, Daniel J.; Kellogg, Michael I.; Park, Walter R.

    2001-03-01

    Critical Deposition Velocity (CDV) is an important design and operational parameter in slurry transport. Almost all existing correlations that are used to predict this parameter have been obtained experimentally from slurry transport tests featuring single solid species in the slurry mixture. No correlations have been obtained to describe this parameter when the slurry mixture contains more than one solid species having a wide range of specific gravities, particle size distributions, and volume concentrations within the overall slurry mixture. There are no physical or empirical bases that can justify the extrapolation or modification of the existing single species correlations to include all these effects. New experiments must be carried out to obtain new correlations that would be suited for these types of slurries, and that would clarify the mechanics of solids deposition as a function of the properties of the various solid species. Our goal in this paper is to describe a robust experimental technique for the accurate determination of the critical deposition velocity associated with the transport of slurries in horizontal or slightly inclined pipes. Because of the relative difficulty encountered during the precise determination of this useful operational parameter, it has been the practice to connect it with some transitional behavior of more easily measurable flow parameters such as the pressure drop along the slurry pipeline. In doing so, the critical deposition velocity loses its unique and precise definition due to the multitude of factors that influence such transitional behaviors. Here, data has been obtained for single species slurries made up of washed garnet and water and flowing through a 1- inch clear pipe. The selected garnet had a narrow particle size distribution with a mean diameter of 100 mm, approximately. The critical deposition velocity was measured for garnet/water slurries of 10, 20, and 30 percent solids concentration by volume.

  4. Evolution of NOx emissions in Europe with focus on road transport control measures

    NASA Astrophysics Data System (ADS)

    Vestreng, V.; Ntziachristos, L.; Semb, A.; Reis, S.; Isaksen, I. S. A.; Tarrasón, L.

    2008-06-01

    European emission trends of nitrogen oxides since 1880 and up to present are presented here and are linked to the evolution of road transport emissions. Road transport has been the dominating source of NOx emissions since 1970, and contributes with 40% to the total emissions in 2005. Five trend regimes have been identified between 1880 and 2005. The first regime (1880-1950) is determined by a slow increase in fuel consumption all over Europe. The second regime (1950-1980) is characterized by a continued steep upward trend in liquid fuel use and by the introduction of the first regulations on road traffic emissions. Reduction in fuel consumption determines the emission trends in the third regime (1980-1990) that is also characterized by important differences between Eastern and Western Europe. Emissions from road traffic continue to grow in Western Europe in this period, and it is argued here that the reason for this continued NOx emission increase is related to early inefficient regulations for NOx in the transport sector. The fourth regime (1990-2000) involves a turning point for road traffic emissions, with a general decrease of emissions in Europe during that decade. It is in this period that we can identify the first emission reductions due to technological abatement in Western Europe. In the fifth regime (2000-2005), the economic recovery in Eastern Europe imposes increased emission from road traffic in this area. Western European emissions are on the other hand decoupled from the fuel consumption, and continue to decrease. The implementation of strict measures to control NOx emissions is demonstrated here to be a main reason for the continued Western European emission reductions. The results indicate that even though the effectiveness of European standards is hampered by a slow vehicle turnover, loopholes in the type-approval testing, and an increase in diesel consumption, the effect of such technical abatement measures is traceable in the evolution of European road traffic emissions over the last 15 years.

  5. Evolution of NOx emissions in Europe with focus on road transport control measures

    NASA Astrophysics Data System (ADS)

    Vestreng, V.; Ntziachristos, L.; Semb, A.; Reis, S.; Isaksen, I. S. A.; Tarrasón, L.

    2009-02-01

    European emission trends of nitrogen oxides since 1880 and up to present are presented here and are linked to the evolution of road transport emissions. Road transport has been the dominating source of NOx emissions since 1970, and contributes with 40% to the total emissions in 2005. Five trend regimes have been identified between 1880 and 2005. The first regime (1880-1950) is determined by a slow increase in fuel consumption all over Europe. The second regime (1950-1980) is characterized by a continued steep upward trend in liquid fuel use and by the introduction of the first regulations on road traffic emissions. Reduction in fuel consumption determines the emission trends in the third regime (1980-1990) that is also characterized by important differences between Eastern and Western Europe. Emissions from road traffic continue to grow in Western Europe in this period, and it is argued here that the reason for this continued NOx emission increase is related to early inefficient regulations for NOx in the transport sector. The fourth regime (1990-2000) involves a turning point for road traffic emissions, with a general decrease of emissions in Europe during that decade. It is in this period that we can identify the first emission reductions due to technological abatement in Western Europe. In the fifth regime (2000-2005), the economic recovery in Eastern Europe imposes increased emission from road traffic in this area. Western European emissions are on the other hand decoupled from the fuel consumption, and continue to decrease. The implementation of strict measures to control NOx emissions is demonstrated here to be a main reason for the continued Western European emission reductions. The results indicate that even though the effectiveness of European standards is hampered by a slow vehicle turnover, loopholes in the type-approval testing, and an increase in diesel consumption, the effect of such technical abatement measures is traceable in the evolution of European road traffic emissions over the last 15 years.

  6. The Australian methane budget: Interpreting surface and train-borne measurements using a chemistry transport model

    NASA Astrophysics Data System (ADS)

    Fraser, Annemarie; Chan Miller, Christopher; Palmer, Paul I.; Deutscher, Nicholas M.; Jones, Nicholas B.; Griffith, David W. T.

    2011-10-01

    We investigate the Australian methane budget from 2005-2008 using the GEOS-Chem 3D chemistry transport model, focusing on the relative contribution of emissions from different sectors and the influence of long-range transport. To evaluate the model, we use in situ surface measurements of methane, methane dry air column average (XCH4) from ground-based Fourier transform spectrometers (FTSs), and train-borne surface concentration measurements from an in situ FTS along the north-south continental transect. We use gravity anomaly data from Gravity Recovery and Climate Experiment to describe the spatial and temporal distribution of wetland emissions and scale it to a prior emission estimate, which better describes observed atmospheric methane variability at tropical latitudes. The clean air sites of Cape Ferguson and Cape Grim are the least affected by local emissions, while Wollongong, located in the populated southeast with regional coal mining, samples the most locally polluted air masses (2.5% of the total air mass versus <1% at other sites). Averaged annually, the largest single source above background of methane at Darwin is long-range transport, mainly from Southeast Asia, accounting for ˜25% of the change in surface concentration above background. At Cape Ferguson and Cape Grim, emissions from ruminant animals are the largest source of methane above background, at approximately 20% and 30%, respectively, of the surface concentration. At Wollongong, emissions from coal mining are the largest source above background representing 60% of the surface concentration. The train data provide an effective way of observing transitions between urban, desert, and tropical landscapes.

  7. Volume transport and mixing of the Faroe Bank Channel overflow from one year of moored measurements

    NASA Astrophysics Data System (ADS)

    Ullgren, J. E.; Darelius, E.; Fer, I.

    2015-10-01

    One-year long time series of current velocity and temperature from ten moorings deployed in the Faroe Bank Channel (FBC) are analysed to describe the structure and variability of the dense overflow plume on daily to seasonal time scales. Mooring arrays are deployed in two sections: located 25 km downstream of the main sill, in the channel that geographically confines the overflow plume at both edges (section C), and 60 km further downstream, over the slope (section S). At section C, the average volume transport of overflow waters (< 3 °C) from the Nordic Seas towards the Iceland Basin is 1.3 ± 0.3 Sv; at Section S, transport of modified overflow water (< 6 °C) is 1.8 ± 0.7 Sv. The volume transport through the slope section is dominated by mesoscale variability at 3-5 day time scale. A simplified view of along-path entrainment of a gravity current is not accurate for the FBC overflow. As the plume proceeds into the stratified ambient water, there is substantial detrainment from the deeper layer (bounded by the 3 °C isotherm), of comparable magnitude to the entrainment into the interfacial layer (between the 3 and 6 °C isotherms). Time series of gradient Richardson number suggests a quiescent plume core capped by turbulent near bottom and interfacial layers in the channel. At section S, in contrast, the entire overflow plume is turbulent. Based on a two-layer heat budget constructed for the overflow, mean diffusivities across the top of the bottom layer, and across the interfacial layer are (30 ± 15) × 10-4 m2 s-1 and (119 ± 43) × 10-4 m2 s-1, respectively.

  8. Volume transport and mixing of the Faroe Bank Channel overflow from one year of moored measurements

    NASA Astrophysics Data System (ADS)

    Ullgren, Jenny E.; Darelius, Elin; Fer, Ilker

    2016-03-01

    One-year long time series of current velocity and temperature from eight moorings deployed in the Faroe Bank Channel (FBC) are analysed to describe the structure and variability of the dense overflow plume on daily to seasonal timescales. Mooring arrays were deployed in two sections: located 25 km downstream of the main sill, in the channel that geographically confines the overflow plume at both edges (section C), and 60 km further downstream, over the slope (section S). At section C, the average volume transport of overflow waters ( < 3 °C) from the Nordic Seas towards the Iceland Basin was 1.3 ± 0.3 Sv; at section S, transport of modified overflow water ( < 6 °C) was 1.7 ± 0.7 Sv. The volume transport through the slope section was dominated by mesoscale variability at 3-5-day timescales. A simplified view of along-path entrainment of a gravity current may not be accurate for the FBC overflow. As the plume proceeds into the stratified ambient water, there is substantial detrainment from the deeper layer (bounded by the 3 °C isotherm), of comparable magnitude to the entrainment into the interfacial layer (between the 3 and 6 °C isotherms). A time series of gradient Richardson numbers suggests a quiescent plume core capped by turbulent near bottom and interfacial layers in the channel. At section S, in contrast, the entire overflow plume is turbulent. Based on a two-layer heat budget constructed for the overflow, time mean vertical diffusivities across the top of the bottom layer and across the interfacial layer were (30 ± 15) × 10-4 and (120 ± 43) × 10-4 m2 s-1, respectively.

  9. Direct electrical transport measurement on a single thermoelectric nanowire embedded in an alumina template.

    PubMed

    Ben Khedim, Meriam; Cagnon, Laurent; Garagnon, Christophe; Serradeil, Valerie; Bourgault, Daniel

    2016-04-28

    Electrical conductivity is a key parameter to increase the performance of thermoelectric materials. However, the measurement of such performance remains complex for 1D structures, involving tedious processing. In this study, we present a non-destructive, rapid and easy approach for the characterization of electrical conductivity of Bi2Te3 based single nanowires. By controlling the nanowire overgrowth, each nanowire emerges in the form of a micrometric hemisphere constituting a unique contact zone for direct nanoprobing. As nanowires need no preliminary preparation and remain in their template during measurement, we avoid oxidation effects and time-consuming processing. Electrical transport results show a low nanowire resistivity for compact nanowires obtained at low overpotential. Such values are comparable to bulk materials and thin films. This method not only confirmed its reliability, but it could also be adopted for other semiconducting or metallic electrodeposited nanowires. PMID:27086560

  10. Comparison of nickel silicide and aluminium ohmic contact metallizations for low-temperature quantum transport measurements

    PubMed Central

    2011-01-01

    We examine nickel silicide as a viable ohmic contact metallization for low-temperature, low-magnetic-field transport measurements of atomic-scale devices in silicon. In particular, we compare a nickel silicide metallization with aluminium, a common ohmic contact for silicon devices. Nickel silicide can be formed at the low temperatures (<400°C) required for maintaining atomic precision placement in donor-based devices, and it avoids the complications found with aluminium contacts which become superconducting at cryogenic measurement temperatures. Importantly, we show that the use of nickel silicide as an ohmic contact at low temperatures does not affect the thermal equilibration of carriers nor contribute to hysteresis in a magnetic field. PMID:21968083

  11. Measurements of radial profiles of He sup 2+ transport coefficients on TFTR (Tokamak Fusion Test Reactor)

    SciTech Connect

    Synakowski, E.J.; Stratton, B.C.; Efthimion, P.C.; Hulse, R.A.; Johnson, D.W.; Mansfield, D.K.; Park, H.; Scott, S.D.; Taylor, G. . Plasma Physics Lab.); Fonck, R.J. . Dept. of Nuclear Engineering and Engineering Physics)

    1990-06-01

    Measurements of the spatial structure of the transport coefficients of He{sup 2+} on the Tokamak Fusion Test Reactor is reported. He{sup 2+} profiles were measured using charge exchange spectroscopy after a helium puff into corotating L-mode plasmas. Modelling shows that the He{sup 2+} diffusivity is about 10 m{sup 2}/s near the plasma edge and drops to below 1 m{sup 2}/s inside of the q = 1 surface. The convective velocity ranges from 1--3 m/s near q = 1 to 20--40 m/s near the edge. The helium diffusivity is on the order of the ion momentum and thermal diffusivity and is greater that than the electron thermal diffusivity. 4 refs., 4 figs.

  12. Electrostatic and magnetic measurements of turbulence and transport in Extrap T2

    NASA Astrophysics Data System (ADS)

    Möller, Anders; Sallander, Eva

    1999-10-01

    Langmuir probe and magnetic pick-up coil measurements are used to study edge turbulence in the Extrap T2 reversed field pinch. Magnetic fluctuations resonant outside the toroidal field reversal surface are observed where previously only