Sample records for transport number measurements

  1. Measuring collective transport by defined numbers of processive and nonprocessive kinesin motors

    PubMed Central

    Furuta, Ken’ya; Furuta, Akane; Toyoshima, Yoko Y.; Amino, Misako; Oiwa, Kazuhiro; Kojima, Hiroaki

    2013-01-01

    Intracellular transport is thought to be achieved by teams of motor proteins bound to a cargo. However, the coordination within a team remains poorly understood as a result of the experimental difficulty in controlling the number and composition of motors. Here, we developed an experimental system that links together defined numbers of motors with defined spacing on a DNA scaffold. By using this system, we linked multiple molecules of two different types of kinesin motors, processive kinesin-1 or nonprocessive Ncd (kinesin-14), in vitro. Both types of kinesins markedly increased their processivities with motor number. Remarkably, despite the poor processivity of individual Ncd motors, the coupling of two Ncd motors enables processive movement for more than 1 ?m along microtubules (MTs). This improvement was further enhanced with decreasing spacing between motors. Force measurements revealed that the force generated by groups of Ncd is additive when two to four Ncd motors work together, which is much larger than that generated by single motors. By contrast, the force of multiple kinesin-1s depends only weakly on motor number. Numerical simulations and single-molecule unbinding measurements suggest that this additive nature of the force exerted by Ncd relies on fast MT binding kinetics and the large drag force of individual Ncd motors. These features would enable small groups of Ncd motors to crosslink MTs while rapidly modulating their force by forming clusters. Thus, our experimental system may provide a platform to study the collective behavior of motor proteins from the bottom up. PMID:23267076

  2. Measuring collective transport by defined numbers of processive and nonprocessive kinesin motors.

    PubMed

    Furuta, Ken'ya; Furuta, Akane; Toyoshima, Yoko Y; Amino, Misako; Oiwa, Kazuhiro; Kojima, Hiroaki

    2013-01-01

    Intracellular transport is thought to be achieved by teams of motor proteins bound to a cargo. However, the coordination within a team remains poorly understood as a result of the experimental difficulty in controlling the number and composition of motors. Here, we developed an experimental system that links together defined numbers of motors with defined spacing on a DNA scaffold. By using this system, we linked multiple molecules of two different types of kinesin motors, processive kinesin-1 or nonprocessive Ncd (kinesin-14), in vitro. Both types of kinesins markedly increased their processivities with motor number. Remarkably, despite the poor processivity of individual Ncd motors, the coupling of two Ncd motors enables processive movement for more than 1 ?m along microtubules (MTs). This improvement was further enhanced with decreasing spacing between motors. Force measurements revealed that the force generated by groups of Ncd is additive when two to four Ncd motors work together, which is much larger than that generated by single motors. By contrast, the force of multiple kinesin-1s depends only weakly on motor number. Numerical simulations and single-molecule unbinding measurements suggest that this additive nature of the force exerted by Ncd relies on fast MT binding kinetics and the large drag force of individual Ncd motors. These features would enable small groups of Ncd motors to crosslink MTs while rapidly modulating their force by forming clusters. Thus, our experimental system may provide a platform to study the collective behavior of motor proteins from the bottom up. PMID:23267076

  3. Transport Numbers in Transdermal Iontophoresis

    PubMed Central

    Mudry, Blaise; Guy, Richard H.; Delgado-Charro, M. Begoña

    2006-01-01

    Parameters determining ionic transport numbers in transdermal iontophoresis have been characterized. The transport number of an ion (its ability to carry charge) is key to its iontophoretic delivery or extraction across the skin. Using small inorganic ions, the roles of molar fraction and mobility of the co- and counterions present have been demonstrated. A direct, constant current was applied across mammalian skin in vitro. Cations were anodally delivered from either simple M+Cl? solutions (single-ion case, M+ = sodium, lithium, ammonium, potassium), or binary and quaternary mixtures thereof. Transport numbers were deduced from ion fluxes. In the single-ion case, maximum cationic fluxes directly related to the corresponding ionic aqueous mobilities were found. Addition of co-ions decreased the transport numbers of all cations relative to the single-ion case, the degree of effect depending upon the molar fraction and mobility of the species involved. With chloride as the principal counterion competing to carry current across the skin (the in vivo situation), a maximum limit on the single or collective cation transport number was 0.6–0.8. Overall, these results demonstrate how current flowing across the skin during transdermal iontophoresis is distributed between competing ions, and establish simple rules with which to optimize transdermal iontophoretic transport. PMID:16443654

  4. Measuring public transport accessibility

    Microsoft Academic Search

    Andy Poole

    2003-01-01

    1. Introduction This paper sets out a review of issues connected with measuring accessibility, particularly in appraisal of transport or development schemes. Accessibility in this context is taken to mean ease of access to transport in order to reach key destinations and services. This is an area that has assumed greater importance in overall policy making in recent years; indeed,

  5. Measuring isotropic subsurface light transport.

    PubMed

    Happel, Kathrin; Dörsam, Edgar; Urban, Philipp

    2014-04-21

    Subsurface light transport can affect the visual appearance of materials significantly. Measuring and modeling this phenomenon is crucial for accurately reproducing colors in printing or for rendering translucent objects on displays. In this paper, we propose an apparatus to measure subsurface light transport employing a reference material to cancel out adverse signals that may bias the results. In contrast to other approaches, the setup enables improved focusing on rough surfaces (e.g. uncoated paper). We derive a measurement equation that may be used to deduce the point spread function (PSF) of subsurface light transport. Main contributions are the usage of spectrally-narrowband exchangeable LEDs allowing spectrally-resolved measurements and an approach based on quadratic programming for reconstructing PSFs in the case of isotropic light transport. PMID:24787793

  6. Measurement techniques for transport noise.

    PubMed

    Brambilla, G

    2001-01-01

    The noise front transport systems (roads, railways and aircraft) are increasing more and more both in space and in time and, therefore, they are still the major factor responsible for environmental noise pollution. The population exposed to transport noise is also increasing. and the corresponding health effects on people (i.e. annoyance and sleep disturbance) become more severe. Due to this current situation international and national legislation has been issued and implemented to reduce the harmful effects of such noise. This paper describes the techniques prescribed by recent Italian legislation to measure road, railway and aircraft noise. PMID:11878435

  7. 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

  8. Measures of Planarity: Crossing Number Stephanie Jones

    E-print Network

    Laison, Josh

    Measures of Planarity: Crossing Number Stephanie Jones Willamette University April 17, 2012 Stephanie Jones (Willamette University) Measures of Planarity: Crossing Number April 17, 2012 1 / 17 #12 distinct edges have at most one crossing. Stephanie Jones (Willamette University) Measures of Planarity

  9. 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

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

    NASA Astrophysics Data System (ADS)

    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 (?) of about 6, was confined in a cell with a square cross section of 7.3×7.3cm2 and a height of 9.4 cm. Heat transport was measured for Rayleigh numbers 2×105numbers 0transport, the Nusselt number, at fixed dimensional rotation rate ?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 of 107 to about 109 is roughly 0.29 with a Ro-dependent coefficient or equivalently is also well fit by a combination of power laws of the form aRa1/5+bRa1/3 . 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.

  11. Accurate Nusselt-number measurements at high Rayleigh numbers

    NASA Astrophysics Data System (ADS)

    Xu, Xiaochao; Bajaj, Kapil M. S.; Ahlers, Guenter

    2000-03-01

    Measurements by others(See, e.g., X. Wu and A. Libchaber, Phys. Rev. A 45), 842 (1992); and J.J. Niemela, L. Skrbek, K.R. Sreenivasan, and R.J. Donnelly, preprint. of the Nusselt number N as a function of the Rayleigh number R, when fitted to N = N0 R ^ ?, yielded ? in the range 0.28 to 0.31. Theoretical values based on different models cover a similar range, making it difficult to distinguish between them on the basis of experiment. We made new measurements in a cylindrical cell of aspect ratio ? = d/h = 1 with a diameter d and height h of 87 mm, using acetone. The cell top was optically flat sapphire, and the bottom diamond-machined aluminum. We measured the heat currents which do not pass through the fluid with an evacuated cell. The fluid properties are known extremely well. Thus we hope to have eliminated most systematic errors. The Prandtl number was 4.0 at the mean temperature of 32.0^oC. The heat currents were measured with an accuracy of 0.1%. The temperature differences were from 0.080^circC to 34.00^circC, corresponding to 2.2× 10^7 <= R <= 9.1× 10^9. A preliminary analysis over the range 10^8 < R < 10^10 yielded ?=0.291±0.004 and N_0=0.16. Further experiments over a larger range of R and ? are under way.

  12. Nature's Microfluidic Transporter: Rotational Cytoplasmic Streaming at High Péclet Numbers

    NASA Astrophysics Data System (ADS)

    van de Meent, Jan-Willem; Tuval, Idan; Goldstein, Raymond E.

    2008-10-01

    Cytoplasmic streaming circulates the contents of large eukaryotic cells, often with complex flow geometries. A largely unanswered question is the significance of these flows for molecular transport and mixing. Motivated by “rotational streaming” in Characean algae, we solve the advection-diffusion dynamics of flow in a cylinder with bidirectional helical forcing at the wall. A circulatory flow transverse to the cylinder’s long axis, akin to Dean vortices at finite Reynolds numbers, arises from the chiral geometry. Strongly enhanced lateral transport and longitudinal homogenization occur if the transverse Péclet number is sufficiently large, with scaling laws arising from boundary layers.

  13. Nature's Microfluidic Transporter: Rotational Cytoplasmic Streaming at High Péclet Numbers

    NASA Astrophysics Data System (ADS)

    van de Meent, J. W.; Tuval, I.; Goldstein, R. E.

    2008-11-01

    Cytoplasmic streaming circulates the fluid contents of large eukaryotic cells, often with complex flow geometries. A largely unanswered question is the significance of these flows for molecular transport and mixing. Motivated by ``rotational streaming'' found in Characean algae we solve the Stokesian advection-diffusion dynamics of flow in a cylinder with bi-directional helical forcing at the wall. Transverse to the cylinder's long axis is generated circulatory flow akin to Dean vortices at finite Reynolds numbers. Strongly enhanced lateral transport and longitudinal homogenization occur if the transverse Péclet number is sufficiently large, with scaling laws arising from the effects of boundary layers.

  14. 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.

  15. Project Background Transportation projects can stall for a number of

    E-print Network

    Minnesota, University of

    Project Background Transportation projects can stall for a number of reasons. One reason is that those responsible for the project lack the skills to move beyond conflicts with resource agency staff work on a pilot program aimed at confronting these two causes. The project had these objectives

  16. The Transport Number of Silver Fluoride Using a Pulsating Current

    E-print Network

    Parkhurst, I. P.

    1914-06-05

    THE TRANSPORT NUMBER OP SILVER FLUORIDE USING A PULSATING CURRENT. I. P. PARKHURST. JUNE 5, 1914. BIBLIOGRAPHY E.W.Washburn and S.J.Bates. The Iodine Coulometer and the Value of the Faraday. Trans. Am. Electrochemical Society. Vol. XXII...

  17. Kinesin-1–driven lipid droplets: Consequences of motor copy number for intracellular transport

    PubMed Central

    Shubeita, G. T.; Tran, S. L.; Xu, J.; Vershinin, M.; Cermelli, S.; Cotton, S. L.; Welte, M. A.; Gross, S. P.

    2009-01-01

    Summary The microtubule motor Kinesin-1 plays central roles in intracellular transport. It has been widely assumed that many cellular cargos are moved by multiple Kinesins and that cargos with more motors move faster and for longer distances; concrete evidence, however, is sparse. Here we rigorously test these notions using lipid droplets in Drosophila embryos: We first employ antibody inhibition, genetics, biochemistry, and particle tracking to demonstrate that Kinesin-1 mediates plus-end droplet motion. We then measure how variation in Kinesin-1 expression affects the forces driving individual droplets and estimate the number of Kinesins actively engaged per droplet. Unlike in vitro, increased motor number results neither in longer travel distances nor higher velocities. Our data suggest that cargos in vivo can simultaneously engage multiple Kinesins and that transport properties are largely unaffected by variation in motor number. Apparently, higher-order regulatory mechanisms rather than motor number per se dominate cargo transport in vivo. PMID:19070579

  18. Measurements of classical transport of fast ions

    NASA Astrophysics Data System (ADS)

    Zhao, L.; Heidbrink, W. W.; Boehmer, H.; McWilliams, R.; Leneman, D.; Vincena, S.

    2005-05-01

    To study the fast-ion transport in a well controlled background plasma, a 3-cm diameter rf ion gun launches a pulsed, ˜300eV ribbon shaped argon ion beam parallel to or at 15° to the magnetic field in the Large Plasma Device (LAPD) [W. Gekelman, H. Pfister, Z. Lucky, J. Bamber, D. Leneman, and J. Maggs, Rev. Sci. Instrum. 62, 2875 (1991)] at UCLA. The parallel energy of the beam is measured by a two-grid energy analyzer at two axial locations (z =0.32m and z =6.4m) from the ion gun in LAPD. The calculated ion beam slowing-down time is consistent to within 10% with the prediction of classical Coulomb collision theory using the LAPD plasma parameters measured by a Langmuir probe. To measure cross-field transport, the beam is launched at 15° to the magnetic field. The beam then is focused periodically by the magnetic field to avoid geometrical spreading. The radial beam profile measurements are performed at different axial locations where the ion beam is periodically focused. The measured cross-field transport is in agreement to within 15% with the analytical classical collision theory and the solution to the Fokker-Planck kinetic equation. Collisions with neutrals have a negligible effect on the beam transport measurement but do attenuate the beam current.

  19. Measurements of classical transport of fast ions

    NASA Astrophysics Data System (ADS)

    Zhao, Liangji

    2005-12-01

    Classical transport of a test fast-ion beam is measured in a quiescent plasma. The experiments and the results are reported in this thesis. The ˜300--400 eV, ribbon-shape (0.5 cm x 3.0 cm), pulsed argon ion beam is generated by a 3 cm RF ion gun. The beam is launched at a pitch angle (0°--22°) into a quiescent LAPD (the LArge P&barbelow;lasma ?evice) argon plasma (Te ˜ 0.2 eV), which is confined by a uniform magnetic field (B ˜ 0.8--1 kG). To minimize the disturbance to the plasma, the ion gun system is electrically isolated from the LAPD vacuum chamber by an isolation flange. A two-grid energy analyzer is the main diagnostic to measure beam energy and cross-field 2-D beam profile. The parallel energy of the beam is measured by the energy analyzer at two axial locations (z = 0.32 m and z = 6.4 m) from the ion gun in LAPD. The calculated ion beam slowing-down time (˜0.1--0.3 ms) is consistent to within 10% with the prediction of classical Coulomb collision theory using the LAPD plasma parameters measured by a Langmuir probe. To measure cross-field transport, the beam is launched at 15 degrees to the magnetic field. The beam then is focused periodically by the magnetic field to avoid geometrical spreading. The radial beam profile measurements are performed at different axial locations where the ion beam is periodically focused. The measured cross-field transport coefficient (˜0.05--0.1 m2/Sec.) is in agreement to within 15% with the analytical classical collision theory and the solution to the Fokker-Planck kinetic equation. Collisions with neutrals have a negligible effect on the beam transport measurement but do attenuate the beam current.

  20. Anomalous Transport in Carbonate Rock - Predictions and Quantitative Measures

    NASA Astrophysics Data System (ADS)

    Bijeljic, B.; Blunt, M. J.

    2014-12-01

    Solute transport in rock subsurface is important in a number of applications such as contaminant hydrology, carbon storage and enhanced oil recovery. Carbonate rock contain most of the world's oil reserves and potentially hold a storage capacity for carbon dioxide. Pore structure in carbonate rock introduces an additional complexity in the form of bimodal pore size distributions, which leads to complex anomalous transport behavior and poses a significant challenge for accurate predictions. We present a new modeling concept that simulates flow and transport on micro-CT images containing the information on inter- and intra-grain pore space of carbonate rock. Navier-Stokes equations are solved for flow in the image voxels comprising the pore space, streamline-based simulation is used to account for advection, and diffusion is superimposed by random walk. Firstly, the model is validated against the experimental NMR measurements in the dual porosity beadpack. Furthermore, the model predictions are made for a number of carbonate rock images which are then classified in terms of heterogeneity of the inter- and intra-grain pore space, heterogeneity in the flow field, and the mass transfer characteristics of the porous media. Finally, we demonstrate the predictive capabilities of the model through an analysis that includes a number of probability density functions (PDFs) measures of non-Fickian transport on the micro-CT images.

  1. Nusselt number measurements for turbulent Rayleigh-Bénard convection

    NASA Astrophysics Data System (ADS)

    Ahlers, Guenter; Nikolaenko, Alexei

    2004-03-01

    We present high-precision measurements of the Nusselt number N as a function of the Rayleigh number R for a cylindrical sample of water (Prandtl number = 4.4) of height L = 50 cm and aspect ratio Gamma = D/L = 1 (D is the diameter) over the range 3 x 10^9 < R < 1 x 10^11. Results were obtained with both Aluminum (conductivity lp = 170 W/m K) and Copper (lp = 400 W/m K) top and bottom plates. The results with Aluminum plates fall significantly below those obtained with Copper plates, thus confirming qualitatively the prediction by Verzicco that plates of finite conductivity diminish the heat transport in the fluid. The Nusselt number N_? is estimated by fitting both data sets to an effective powerlaw for N_? multiplied by a correction factor f(X) which depends on the ratio X of the thermal resistance of the fluid to that of the plates as suggested by Verzicco. The result is consistent with the structure of the Grossmann-Lohse (GL) model, but will require an adjustment of the model parameters. Near R = 10^11, the effective exponent ?_eff = 0.325 of N_? almost has reached the asymptotic value 1/3 of the GL model for our Prandtl number.

  2. Survey of Concrete Transport Properties and their Measurement

    E-print Network

    Bentz, Dale P.

    materials, building technology, capillary flow, cement, chloride ions, concentration profiles, concrete. . . Survey of Concrete Transport Properties and their Measurement NicosS. Martys U of concrete. The basic theory and measurement methods are discussed. Emphasis is placed on transport

  3. Measuring and modelling longshore sediment transport

    NASA Astrophysics Data System (ADS)

    Esteves, Luciana S.; Williams, Jon J.; Lisniowski, Maria A.

    2009-06-01

    Field measurements of longshore sediment transport (LST) was undertaken on barred and non-barred beaches composed of fine, medium and coarse sands in Brazil, Denmark and Portugal. Measurements and predictions of vertical suspended sediment concentration profiles ( C-Profiles) and cross-shore hydrodynamic parameters were then combined in a new semi-empirical model for prediction of LST ( LT-MOD). Instantaneous LST predictions from LT-MOD and well-known bulk LST formulae were compared. Tests using LT-MOD to simulate measured changes in shoreline position in southern Brazil for periods of c. two years showed that LT-MOD gave more accurate predictions than existing bulk LST formulae. Results indicate that LT-MOD may have practical utility at sites where access to equipment is limited and where reliable estimates of LST are required over extended periods.

  4. Number and Measurement. Papers from a Research Workshop.

    ERIC Educational Resources Information Center

    Lesh, Richard A., Ed.; Bradbard, David A., Ed.

    Seven papers presented at a research conference on number and measurement are presented in this volume. The first paper provides an overview of research concerning number and measurement, and suggests directions for future research. The second paper discusses the relationships between measurement and number concepts, and psychological and…

  5. 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.

  6. 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.

  7. 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-? (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.

  8. Proposal to the PAC Number Measurement of +

    E-print Network

    Credé, Volker

    framework, one that goes beyond the quasi two-body asumption. Partial wave analyses or other analyses based as longitudinally-polarized frozen-spin target (FROST). We intend to measure three single-polarization observables (Px, Py, Pz) and nine double-polarization observables (Ps, c x , Ps, c y , Ps, c z , Px , Py , Pz

  9. Spatially Resolved Ballistic Optoelectronic Transport Measured by Quantized

    E-print Network

    Ludwig-Maximilians-Universität, München

    Spatially Resolved Ballistic Optoelectronic Transport Measured by Quantized Photocurrent and analyze the ballistic, nonequilibrium flow of photogenerated electrons in a nanoscale circuit. Electron of the electron modes in the QPC. KEYWORDS Ballistic optoelectronic quantum transport, nanoscale electronics Q

  10. Ranking of Intuitionistic Fuzzy Numbers by New Distance Measure

    E-print Network

    Debaroti Das; P. K. De

    2014-10-27

    Ranking of intuitionsitic fuzzy number plays a vital role in decision making and other intuitionistic fuzzy applications. In this paper, we propose a new ranking method of intuitionistic fuzzy number based on distance measure. We first define a distance measure for interval numbers based on Lp metric and further generalize the idea for intuitionistic fuzzy number by forming interval with their respective value and ambiguity indices. Finally, some comparative results are given in tabular form.

  11. Accumulationmode aerosol number concentrations in the Arctic during the ARCTAS aircraft campaign: Longrange transport

    E-print Network

    Jimenez, Jose-Luis

    Accumulationmode aerosol number concentrations in the Arctic during the ARCTAS aircraft campaign of the Troposphere from Aircraft and Satellites (ARCTAS) campaign. We focus on transport from the Asian continent. We find marked contrasts in the number concentration (NLSP), transport efficiency (TEN_LSP, the fraction

  12. Transportation and Greenhouse Gas Emissions: Measurement, Causation and Mitigation

    E-print Network

    Transportation and Greenhouse Gas Emissions: Measurement, Causation and Mitigation Oak Ridge of the transportation sector's contribution to GHG emissions. It can do so by combining (1) the many national passenger of GHG emission rates for transportation activities, and by (3) using our expertise in supply chain

  13. 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...

  14. 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...

  15. Nusselt Number Measurements for Turbulent Rayleigh-Bénard Convection

    NASA Astrophysics Data System (ADS)

    Nikolaenko, Alexei; Ahlers, Guenter

    2003-08-01

    We present high-precision measurements of the Nusselt number N as a function of the Rayleigh number R for a cylindrical sample of water (Prandtl number ?=4.4) of height L?50 cm and aspect ratio ??D/L?1 (D is the diameter) for 3×109?R?6×1010. For R?3×109 the data are consistent with existing results for acetone (?=4.0, R?3×109). There the measurements are also consistent with a model by Grossmann and Lohse (GL). As R increases, the measurements fall below the GL prediction. Near R=6×1010 the prediction is 8% above the data.

  16. A linear-time algorithm for the bottleneck transportation problem with a fixed number of sources

    Microsoft Academic Search

    Dorit S. Hochbaum; Gerhard J. Woeginger

    1999-01-01

    We investigate a special case of the bottleneck transportation problem where the number s of sources is bounded by a constant and not part of the input. For the subcase s=2, a best-possible linear-time algorithm has been derived by Varadarajan [Oper. Res. Lett. 10 (1991) 525–529]. In this note we show that for any fixed number s?1, the bottleneck transportation

  17. Stochastic quantum trajectories in a QND measurement of photon number

    SciTech Connect

    Bukach, A. A., E-mail: a.bukach@dragon.bas-net.by; Kilin, S. Ya. [National Academy of Sciences of Belarus, Stepanov Institute of Physics (Belarus)

    2007-04-15

    An analysis is presented of the time evolution of an optical field during a quantum nondemolition measurement of photon number using the cross-Kerr interaction between the signal and probe fields. It is shown that the signal field state collapses into a Fock state only asymptotically (in the infinite time limit), remaining in a superposition of two Fock states (Fock-state qubit) throughout most of the measurement period. Estimates are obtained both for the time required to measure photon number to the desired accuracy and for the Fock-state qubit lifetime.

  18. Electronic measurement and control of spin transport in silicon

    Microsoft Academic Search

    Ian Appelbaum; Biqin Huang; Douwe J. Monsma

    2007-01-01

    The spin lifetime and diffusion length of electrons are transport parameters that define the scale of coherence in spintronic devices and circuits. As these parameters are many orders of magnitude larger in semiconductors than in metals, semiconductors could be the most suitable for spintronics. So far, spin transport has only been measured in direct-bandgap semiconductors or in combination with magnetic

  19. Transportation control measure: State Implementation Plan guidance (revised final report)

    Microsoft Academic Search

    D. S. Eisinger; E. A. Deakin; L. A. Mahoney; R. E. Morris; R. G. Ireson

    1990-01-01

    The document has been developed for the United States Environmental Protection Agency to summarize current knowledge about transportation control measures (TCMs). The target audience includes transportation and air quality management staff at all government levels. The guidance development effort is motivated by the need to provide post-1987 guidance to attain National Ambient Air Quality Standards (NAAQS). The document provides descriptions

  20. 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.

  1. Performance measurement in transport sector analysis

    Microsoft Academic Search

    Margarita Išoraite

    2004-01-01

    The article analyses the following issues: 1. Performance measurement in literature. The performance measurement has an important role to play in the efficient and effective management of organizations. Kaplan and Johnson highlighted the failure of the financial measures to reflect changes in the competitive circumstances and strategies of modern organizations. Many authors have focused attention on how organizations can design

  2. Nusselt number measurements for turbulent Rayleigh-Bénard convection

    NASA Astrophysics Data System (ADS)

    Nikolaenko, Alexei; Ahlers, Guenter

    2003-11-01

    We present high-precision measurements of the Nusselt number l N as a function of the Rayleigh number R for a cylindrical sample of water (Prandtl number ? = 4.4) of height L ? 50 cm and aspect ratio ? ? D/L ? 1 (D is the diameter) for 3× 10^9 ? R ? 1× 10^11. For R ? 3× 10^9 the data are consistent with existing results for acetone (? = 4.0, R ? 3× 10^9). There the measurements are also consistent with a model by Grossmann and Lohse (GL). As R increases, the measurements fall below the GL prediction. Near R = 10^11 the prediction is 12% above the data. We will discuss the possibility that the difference is caused by the effect of the finite conductivity of the top and bottom plates on the fluid flow, as suggested by Verzicco.

  3. Numerical Upscaling of Transport Through Obstructed Regions Over a Broad Range of Reynolds Numbers

    NASA Astrophysics Data System (ADS)

    Sund, N. L.; Bolster, D.; Mattis, S. A.

    2014-12-01

    While historically flow and transport in porous media has focused on low Reynolds number and Peclet number regimes there are a variety of examples relevant to environmental fluid dynamics where higher Reynolds number flows are important. A common example might include flow and transport through wetlands where plants act as the solid phase of an effective porous medium. In particular, heterogeneity in the flow field due to presence of the solid phases gives rise to complex transport and mixing behaviors that cannot be upscaled at pre-asymptotic times using conventional approaches. We numerically simulate pore-scale flow and transport through obstructed domains over a range of Reynolds numbers from 15 to 280 and then upscale transport. We upscale using a correlated continuous time random walk (correlated CTRW) model, originally introduced in [1]. We then assess the correlated CTRW's ability to predict observables for both asymptotic and pre-asymptotic time scales and compare our results to those of a classical CTRW to determine when velocity correlations must be accounted for. REFERENCES[1] T.L. Borgne, M. Dentz, J. Carrera: Lagrangian statistical model for transport in highly heterogeneous velocity fields, Physical Review Letters 101 (2008) 090601.

  4. 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…

  5. Thermal Transport Measurements of Individual Multiwalled Nanotubes

    Microsoft Academic Search

    P. Kim; L. Shi; A. Majumdar; P. L. McEuen

    2001-01-01

    The thermal conductivity and thermoelectric power of a single carbon nanotube were measured using a microfabricated suspended device. The observed thermal conductivity is more than 3000 W\\/K m at room temperature, which is 2 orders of magnitude higher than the estimation from previous experiments that used macroscopic mat samples. The temperature dependence of the thermal conductivity of nanotubes exhibits a

  6. 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.

  7. 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.

  8. Reynolds Number Effects on Leading Edge Radius Variations of a Supersonic Transport at Transonic Conditions

    NASA Technical Reports Server (NTRS)

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

    2001-01-01

    A computational study focused on leading-edge radius effects and associated Reynolds number sensitivity for a High Speed Civil Transport configuration at transonic conditions was conducted as part of NASA's High Speed Research Program. The primary purposes were to assess the capabilities of computational fluid dynamics to predict Reynolds number effects for a range of leading-edge radius distributions on a second-generation supersonic transport configuration, and to evaluate the potential performance benefits of each at the transonic cruise condition. Five leading-edge radius distributions are described, and the potential performance benefit including the Reynolds number sensitivity for each is presented. Computational results for two leading-edge radius distributions are compared with experimental results acquired in the National Transonic Facility over a broad Reynolds number range.

  9. 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.

  10. Measurement of gas transport properties for chemical vapor infiltration

    SciTech Connect

    Starr, T.L.; Hablutzel, N. [Georgia Inst. of Tech., Atlanta, GA (United States). School of Materials Science and Engineering

    1996-12-01

    In the chemical vapor infiltration (CVI) process for fabricating ceramic matrix composites (CMCs), transport of gas phase reactant into the fiber preform is a critical step. The transport can be driven by pressure or by concentration. This report describes methods for measuring this for CVI preforms and partially infiltrated composites. Results are presented for Nicalon fiber cloth layup preforms and composites, Nextel fiber braid preforms and composites, and a Nicalon fiber 3-D weave composite. The results are consistent with a percolating network model for gas transport in CVI preforms and composites. This model predicts inherent variability in local pore characteristics and transport properties, and therefore, in local densification during processing; this may lead to production of gastight composites.

  11. A device for measuring sonic velocity and compressor Mach number

    NASA Technical Reports Server (NTRS)

    Huber, Paul W; Kantrowitz, Arthur

    1947-01-01

    A device has been developed which measures the velocity of sound in fluids at stagnation and is especially adaptable to turbine and compressor testing for which the constituency of the working fluid may be in doubt. By utilizing the shaft frequency of a rotary compressor, the instrument can also be used to provide a direct measurement of the compressor Mach number (ratio of blade-tip velocity to inlet velocity of sound at stagnation). A Helmholtz resonator is employed in the measurement of the sound velocity. Viscous effects in the orifice of the Helmholtz resonator are shown to be important and can be taken into account with the help of a parameter obtained from Stokes solution of the flow near an oscillating wall. This parameter includes the kinematic viscosity of the fluid and the frequency of sound in the resonator. When these effects are recognized, the resonator can be calibrated to measure velocity of sound or compressor Mach number to an accuracy of better than 0.5 percent.

  12. 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.

  13. Reynolds number measurements in Rayleigh-Benard convection

    NASA Astrophysics Data System (ADS)

    Funfschilling, Denis

    2005-03-01

    We determined the Reynolds number Re in cylindrical cells of aspect ratio ??D/L = 1 (D = diameter, L = height) filled with water at a mean temperature of 40^oC and heated from below for Rayleigh numbers R from 10^9 to 10^11. It is well known that the main flow structure in this system is a collection of hot and cold plumes and an associated large-scale circulation (LSC). We measured the temperature of the cell side-wall as a function of time at eight azimuthal locations on the horizontal mid-plane. The cross-correlation functions of temperatures on opposite sides of the cell indicate that localized hot or cold volumes associated with the LSC survive for a time comparable to the turnover time ? as they follow the LSC. >From maxima of the cross-correlation functions we find ?, and from it the Reynolds number Re?(4L/?)(L/?) (? is the kinematic viscosity), of the LSC. The results are consistent with measurements by others ootnotetextX.-L. Qiu and P. Tong, Phys. Rev. E 66, 026308 (2002). for R 10^ 10 and with the prediction of Grossmann and Lohse footnoteS. Grossmann and D. Lohse, Phys. Rev. E 66, 016305 (2002)..

  14. Creation, Transport and Measurement of Bright Relativistic Electron Beams

    Microsoft Academic Search

    Chad Bennett McKee

    1994-01-01

    This thesis deals with three topics relevant to linac-driven free electron lasers: the creation, transport and measurement of bright relativistic electron beams. Thermionic microwave electron guns produce bright electron beams that are well suited to drive free electron lasers, FELs. The rf fields in the gun cause some of the emitted electrons to reverse direction and strike the cathode. These

  15. EXPLORING SPATIAL AND TEMPORAL PERFORMANCE MEASUREMENT IN METROPOLITAN TRANSPORTATION SAFETY

    E-print Network

    Bertini, Robert L.

    , improving pedestrian and bicycle safety, and improving safety around school zones. Efforts in eachEXPLORING SPATIAL AND TEMPORAL PERFORMANCE MEASUREMENT IN METROPOLITAN TRANSPORTATION SAFETY-0751 USA Tel: +1 503 725 4249, Fax: +1 503 725 5950 E-mail: moest@pdx.edu Abstract: Traffic safety strongly

  16. 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.

  17. LIF Diagnostic for Measuring Beam-Transport Magnetic Fields

    Microsoft Academic Search

    T. G. Jones; W. A. Noonan; P. F. Ottinger

    1996-01-01

    A novel, spatially-resolved diagnostic is being developed to measure magnetic fields associated with intense ion beam propagation through a low-pressure gas, as is envisioned for light ion-driven ICF. The diagnostic technique uses laser-induced fluorescence (LIF) spectroscopy, and can be varied to measure either small or large fields. Small fields, as expected in ballistic transport with solenoidal lens focusing using ~

  18. LIF Diagnostic for Measuring Beam-Transport Magnetic Fields

    Microsoft Academic Search

    T. G. Jones; D. D. Hinshelwood; J. M. Neri; P. F. Ottinger; W. A. Noonan

    1997-01-01

    A novel, spatially-resolved diagnostic is being developed to measure magnetic fields associated with intense ion beam propagation through a low-pressure gas, as is envisioned for light ion-driven ICF. The diagnostic technique uses laser-induced fluorescence (LIF) spectroscopy, and can be varied to measure either small or large fields. Small fields, as expected in ballistic transport with solenoidal lens focusing using ~

  19. Convective heat transport in a rotating fluid layer of infinite Prandtl number: Optimum fields and upper bounds on Nusselt number

    NASA Astrophysics Data System (ADS)

    Vitanov, Nikolay K.

    2003-02-01

    By means of the Howard-Busse method of the optimum theory of turbulence we investigate numerically upper bounds on convective heat transport for the case of infinite fluid layer with stress-free vertical boundaries rotating about a vertical axis. We discuss the case of infinite Prandtl number, 1-? solution of the obtained variational problem and optimum fields possessing internal, intermediate, and boundary layers. We investigate regions of Rayleigh and Taylor numbers R and Ta, where no analytical bounds can be derived, and compare the analytical and numerical bounds for these regions of R and Ta where such comparison is possible. The increasing rotation has a different influence on the rescaled optimum fields of velocity w1, temperature ?1 and the vertical component of the vorticity f1. The increasing Ta for fixed R leads to vanishing of the boundary layers of w1 and ?1. Opposite to this, the increasing Ta leads first to a formation of boundary layers of the field f1 but further increasing the rotation causes vanishing of these boundary layers. We obtain optimum profiles of the horizontal averaged total temperature field which could be used as hints for construction of the background fields when applying Doering-Constantin method to the problems of rotating convection. The wave number ?1 corresponding to the optimum fields follows the asymptotic relationship ?1=(R/5)1/4 for intermediate Rayleigh numbers. However, when R becomes large with respect to Ta, after a transition region, the power law for ?1 becomes close to the power law for the case without rotation. The Nusselt number Nu is close to the nonrotational bound 0.32R1/3 for the case of large R and small Ta. Nu decreases with increasing Taylor number. Thus, the upper bounds reflect the tendency of inhibiting thermal convection by increasing rotation for a fixed Rayleigh number. For the regions of Rayleigh and Taylor numbers where the numerical and asymptotic bounds on Nu can be compared, the numerical bounds are about 70% lower than the asymptotic bounds.

  20. Convective heat transport in a rotating fluid layer of infinite Prandtl number: optimum fields and upper bounds on Nusselt number.

    PubMed

    Vitanov, Nikolay K

    2003-02-01

    By means of the Howard-Busse method of the optimum theory of turbulence we investigate numerically upper bounds on convective heat transport for the case of infinite fluid layer with stress-free vertical boundaries rotating about a vertical axis. We discuss the case of infinite Prandtl number, 1-alpha solution of the obtained variational problem and optimum fields possessing internal, intermediate, and boundary layers. We investigate regions of Rayleigh and Taylor numbers R and Ta, where no analytical bounds can be derived, and compare the analytical and numerical bounds for these regions of R and Ta where such comparison is possible. The increasing rotation has a different influence on the rescaled optimum fields of velocity w(1), temperature theta(1) and the vertical component of the vorticity f(1). The increasing Ta for fixed R leads to vanishing of the boundary layers of w(1) and theta(1). Opposite to this, the increasing Ta leads first to a formation of boundary layers of the field f(1) but further increasing the rotation causes vanishing of these boundary layers. We obtain optimum profiles of the horizontal averaged total temperature field which could be used as hints for construction of the background fields when applying Doering-Constantin method to the problems of rotating convection. The wave number alpha(1) corresponding to the optimum fields follows the asymptotic relationship alpha(1)=(R/5)(1/4) for intermediate Rayleigh numbers. However, when R becomes large with respect to Ta, after a transition region, the power law for alpha(1) becomes close to the power law for the case without rotation. The Nusselt number Nu is close to the nonrotational bound 0.32R(1/3) for the case of large R and small Ta. Nu decreases with increasing Taylor number. Thus, the upper bounds reflect the tendency of inhibiting thermal convection by increasing rotation for a fixed Rayleigh number. For the regions of Rayleigh and Taylor numbers where the numerical and asymptotic bounds on Nu can be compared, the numerical bounds are about 70% lower than the asymptotic bounds. PMID:12636815

  1. Flow Velocity Computation, from Temperature and Number Density Measurements using Spontaneous Raman Scattering, for Supersonic Chemically Reacting Flows.

    NASA Astrophysics Data System (ADS)

    Satish Jeyashekar, Nigil; Seiner, John

    2006-11-01

    The closure problem in chemically reacting turbulent flows would be solved when velocity, temperature and number density (transport variables) are known. The transport variables provide input to momentum, heat and mass transport equations leading to analysis of turbulence-chemistry interaction, providing a pathway to improve combustion efficiency. There are no measurement techniques to determine all three transport variables simultaneously. This paper shows the formulation to compute flow velocity from temperature and number density measurements, made from spontaneous Raman scattering, using kinetic theory of dilute gases coupled with Maxwell-Boltzmann velocity distribution. Temperature and number density measurements are made in a mach 1.5 supersonic air flow with subsonic hydrogen co-flow. Maxwell-Boltzmann distribution can be used to compute the average molecular velocity of each species, which in turn is used to compute the mass-averaged velocity or flow velocity. This formulation was validated by Raman measurements in a laminar adiabatic burner where the computed flow velocities were in good agreement with hot-wire velocity measurements.

  2. Low Reynolds number Couette flow facility for drag measurements

    NASA Astrophysics Data System (ADS)

    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.

  3. Measurement of Water Transport from Saturated Pumice Aggregates to Hardening Cement Paste

    E-print Network

    Bentz, Dale P.

    Measurement of Water Transport from Saturated Pumice Aggregates to Hardening Cement Paste by Pietro-ray absorption showed that considerable transport of water from saturated lightweight aggregates (pumice

  4. PHYSICAL REVIEW B VOLUME 51, NUMBER 23 15 JUNE 1995-I Transport in channels and films with rough surfaces

    E-print Network

    Meyerovich, Alex

    PHYSICAL REVIEW B VOLUME 51, NUMBER 23 15 JUNE 1995-I Transport in channels and films with rough of transport of almost ballistic particles near rough boundaries with an emphasis on thin films and narrow of quantized motion across the film. All the transport coefBcients are expressed via the first two angular

  5. Modeling source contributions to submicron particle number concentrations measured in Rochester, New York

    SciTech Connect

    Ogulei, D.; Hopke, P.K.; Chalupa, D.C.; Utell, M.J. [Clarkson University, Potsdam, NY (United States)

    2007-02-15

    An advanced receptor model was used to elicit source information based on ambient submicron (0.01-0.47 {mu}m) particle number concentrations, gaseous species, and meteorological variables measured at the New York State Department of Environmental Conservation central monitoring site in Rochester, NY. Four seasonal data sets (winter, spring, summer, and fall) were independently investigated. A total of ten different sources were identified, including two traffic factors, two nucleation factors, industrial emissions, residential/commercial heating, secondary nitrate, secondary sulfate, ozone-rich secondary aerosol, and regionally transported aerosol. The resolved sources were generally characterized by similar number modes for either winter, spring, summer or fall. The size distributions for nucleation were dominated by the smallest particles ({lt}10-30 nm) that gradually grew to larger sizes as could be seen by observing the volume profiles. In addition, the nucleation factors were closely linked to traffic rush hours suggesting that cooling of tail-pipe emissions may have induced nucleation activity in the vicinity of the highways. Industrial emissions were dominated by emissions from coal-fired power plants that were located to the northwest of the sampling site. These facilities represent the largest point emission sources of SO{sub 2}, and probably ultrafine ({lt}0.1 {mu}m) or submicron particles, in Rochester. Regionally transported material was characterized by accumulation mode particles. Air parcel back-trajectories showed transport of air masses from the industrial midwest.

  6. Charge transport measurements of vertically aligned carbon nanofibers

    NASA Astrophysics Data System (ADS)

    Zhang, Lan

    2005-07-01

    Vertically aligned carbon nanofibers (VACNFs) have found a variety of electronic applications. To further realize these applications, a good understanding of the charge transport properties is essential. In this work, charge transport properties have been systematically measured for three types of VACNF forests with Ni as catalyst, namely VACNFs grown by direct current PECVD, and inductively coupled PECVD at both normal pressure and low pressure. The structure and composition of these nanofibers have also been investigated in detail prior to the charge transport measurements. Four-probe I-V measurements on individual nanofibers have been enabled by the fabrication of multiple metal ohmic contacts on individual fibers that exhibited resistance of only a few kO. An O2 plasma reactive ion etch method has been used to achieve ohmic contacts between the nanofibers and Ti/Au, Ag/Au, Cd/Au, and Cr/Au electrodes. Direct current VACNFs exhibit linear I-V behavior at room temperature, with a resistivity of approximately 4.2 x 10-3 O·cm. Our measurements are consistent with a dominant transport mechanism of electrons traveling through intergraphitic planes in the dc VACNFs. The resistivity of these fibers is almost independent of temperature, and the contact resistance decreases as temperature increases. Further studies reveal that the 10--15 nm thick graphitic outer layer dominates the charge transport properties of do VACNFs. This is demonstrated by comparison of charge transport properties of as-grown VACNFs and VACNFs with the outer layer partially removed by oxygen plasma reactive ion etch. The linear I-V behavior of the fibers does not vary as this outer layer becomes thinner, but displays a drastic shift to a rectifying behavior when this layer is completely stripped away from some regions of the nanofiber. This shift may be related with the compositional differences in the outer layer and the inner core of the nanofibers. Two-probe charge transport measurements on inductively coupled PECVD grown VACNFs indicate linear I-V behavior, and the resistivity of both types of inductively coupled PECVD grown VACNFs is on the order of 10-3 to 10-4 O·cm.

  7. Number-resolved master equation approach to quantum transport under the self-consistent Born approximation

    NASA Astrophysics Data System (ADS)

    Liu, Yu; Jin, JinShuang; Li, Jun; Li, XinQi; Yan, YiJing

    2013-10-01

    We construct a particle-number ( n)-resolved master equation (ME) approach under the self-consistent Born approximation (SCBA) for quantum transport through mesoscopic systems. The formulation is essentially non-Markovian and incorporates the interplay of the multi-tunneling processes and many-body correlations. The proposed n-SCBA-ME goes beyond the scope of the Born-Markov master equation, being applicable to transport under small bias voltage, in non-Markovian regime and with strong Coulomb correlations. For steady state, it can recover not only the exact result of noninteracting transport under arbitrary voltages, but also the challenging nonequilibrium Kondo effect. Moreover, the n-SCBA-ME approach is efficient for the study of shot noise. We demonstrate the application by a couple of representative examples, including particularly the nonequilibrium Kondo system.

  8. Neutron spectroscopy measurements of tritium beam transport at JET

    NASA Astrophysics Data System (ADS)

    Nocente, M.; Albergante, M.; Eriksson, J.; Conroy, S.; Ericsson, G.; Farina, D.; Hellesen, C.; Källne, J.; Popovichev, S.; Tardocchi, M.; Gorini, G.; contributors, JET-EFDA

    2014-10-01

    A detailed description of the 14 MeV neutron emission in plasmas heated by neutral beam injection has been carried out by coupling Monte Carlo calculations of the neutron emission spectrum with TRANSP modelling of the beam ion energy distributions. The model is used to study tritium beam injection experiments of the JET trace tritium campaign for internal transport barrier (ITB) and H-mode discharges. For ITB discharges, the measured neutron emission spectrum is well described by modelling using as input the beam ion distribution calculated with TRANSP. For H mode discharges the neutron spectrum can be reproduced only if high energy tritons are lost from the plasma, suggesting the possible role of low frequency tearing modes on the beam ions. The presented results are of relevance for tritium beam transport studies in trace tritium experiments and, more generally, for deuterium and tritium transport studies in high power experiments using neutron emission spectroscopy.

  9. 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).

  10. Direct measurement of hole transport dynamics in DNA

    NASA Astrophysics Data System (ADS)

    Lewis, Frederick D.; Liu, Xiaoyang; Liu, Jianqin; Miller, Scott E.; Hayes, Ryan T.; Wasielewski, Michael R.

    2000-07-01

    Our understanding of oxidative damage to double helical DNA and the design of DNA-based devices for molecular electronics is crucially dependent upon elucidation of the mechanism and dynamics of electron and hole transport in DNA. Electrons and holes can migrate from the locus of formation to trap sites, and such migration can occur through either a single-step ``superexchange'' mechanism or a multistep charge transport ``hopping'' mechanism. The rates of single-step charge separation and charge recombination processes are found to decrease rapidly with increasing transfer distances, whereas multistep hole transport processes are only weakly distance dependent. However, the dynamics of hole transport has not yet been directly determined. Here we report spectroscopic measurements of photoinduced electron transfer in synthetic DNA that yield rate constants of ~5×10 7s-1 and 5×10 6s-1, respectively, for the forward and return hole transport from a single guanine base to a double guanine base step across a single adenine. These rates are faster than processes leading to strand cleavage, such as the reaction of guanine cation radical with water, thus permitting holes to migrate over long distances in DNA. However, they are too slow to compete with charge recombination in contact ion pairs, a process which protects DNA from photochemical damage.

  11. LIF Diagnostic for Measuring Beam-Transport Magnetic Fields

    NASA Astrophysics Data System (ADS)

    Jones, T. G.; Noonan, W. A.; Ottinger, P. F.

    1996-11-01

    A novel, spatially-resolved diagnostic is being developed to measure magnetic fields associated with intense ion beam propagation through a low-pressure gas, as is envisioned for light ion-driven ICF. The diagnostic technique uses laser-induced fluorescence (LIF) spectroscopy, and can be varied to measure either small or large fields. Small fields, as expected in ballistic transport with solenoidal lens focusing using ~ 1 Torr gas, produce Zeeman shifts, ? ?_Z, smaller than the transition linewidth, ? ?. High sensitivity to measure these shifts is achieved by a variation on the Babcock technique.^1 Large fields, as expected in self-pinched transport using 10--100 mTorr gas, produce ? ?Z larger than ? ?, which can be measured with a high-resolution spectrometer. Results of proof-of-principle experiments using calibrated B-fields for both the small- and large-field techniques will be presented. Progress in fielding this diagnostic on the Gamble-II accelerator for beam-transport studies will also be presented. This work is supported by DoE through Sandia National Laboratories. ^ NRC-NRL Research Associate. ^ Present address University of Maryland, College Park, MD. ^1 W.A. Noonan, et al., accepted for publication in Rev. Sci. Instrum.

  12. 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 ?. For E < 1 inviscid scaling theory predicts and simulations confirm the large Ra scaling law Nu-1 ? C(1)?(-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(?), is determined by the efficiency of the thermal boundary layers (laminar: 0.28 ? ? ? 0.31, turbulent: ? ~ 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

  13. Reliability as a measure of transportation system performance

    E-print Network

    Jackson, Dena Delise

    2000-01-01

    December 2000 Major Subject: Civil Engineering RELIABILITY AS A MEASURE OF TRANSPORTATION SYSTEM PERFORMANCE A Thesis by DENA DELISE JACKSON Submitted to Texas ASM University in partial fulfillment of the requirements for the degree of MASTER... OF SCIENCE Approved as to style and content by: Mark D. Hickman (Chair of Committee) aurence R. Rilett (Member) Katherine F. Turnbull (Member) . Niedzvvec (Head of Department) December 2000 Major Subject: Civil Engineering ABSTRACT Reliability...

  14. LIF Diagnostic for Measuring Beam-Transport Magnetic Fields

    NASA Astrophysics Data System (ADS)

    Jones, T. G.; Hinshelwood, D. D.; Neri, J. M.; Ottinger, P. F.; Noonan, W. A.

    1997-11-01

    A novel, spatially-resolved diagnostic is being developed to measure magnetic fields associated with intense ion beam propagation through a low-pressure gas, as is envisioned for light ion-driven ICF. The diagnostic technique uses laser-induced fluorescence (LIF) spectroscopy, and can be varied to measure either small or large fields. Small fields, as expected in ballistic transport with solenoidal lens focusing using ~ 1 Torr gas, produce Zeeman shifts, ? ?_Z, smaller than the transition linewidth, ? ?. High sensitivity to measure these shifts is achieved by a variation on the Babcock technique.^1 Large fields, as expected in self-pinched transport using 1--100 mTorr gas, produce ? ?Z larger than ? ?. These ? ?Z will be resolved using an etalon as a narrowband, high-throughput optical filter. Available results from benchtop experiments using calibrated B-fields for both the small- and large-field techniques, and progress in fielding this diagnostic on the Gamble-II accelerator for beam-transport studies will be presented. Work supported by DOE through Sandia National Laboratories. ^ National Research Council Research Associate. ^ Present address University of Maryland, College Park, MD. ^1 W.A. Noonan, et al., Rev. Sci. Instrum. 68, 1032 (1997).

  15. Local measurements of turbulent angular momentum transport in Taylor-Couette flow.

    NASA Astrophysics Data System (ADS)

    Burin, Michael; Schartman, Ethan; Ji, Hantao

    2007-11-01

    We report on velocity fluctuations and the fluctuation-driven radial transport of angular momentum in turbulent wide-gap Taylor-Couette flow (2x10^3< Re <2x10^5). Fluctuation r.m.s. levels and the mean specific angular momentum are found to be nearly constant over radius, in accordance with previous studies featuring narrower gaps. Synchronized dual beam Laser Doppler Velocimetry (2D LDV) is used to directly measure the r-? Reynolds stress component, revealing an approximate power-law scaling in the non-dimensional angular momentum transport: G Re^1.77±0.07. The local exponent between 1.7 and 1.8 confirms previous measurements of torque in similar flows at high Reynolds numbers; its constancy over two decades differs from previous work however, and is attributed to the wide-gap geometry of our apparatus (ratio of cylinder radii ?˜ 0.35). 2D LDV allows for decomposition of the turbulent transport to assess the relative roles of fluctuation intensity and cross-correlation. We find that the increasing transport with Re is solely due to intensifying fluctuations; changes in cross-correlation for these Reynolds numbers are insignificant.

  16. Observation and Measurement of Turbulent Radial Transport in a Dipole

    NASA Astrophysics Data System (ADS)

    Roberts, T. M.; Mauel, M. E.; Senter, A. M.; Singh, D. P.; Worstell, M. W.; Qin, A. Z.

    2011-10-01

    We present results from measurements of turbulent radial in a mechanically supported dipole. A new diagnostic composed of 16 floating potential probes and 15 ion saturation probes alternately placed on a 90 degree arc. By considering the difference in floating potential between two tips, we measure the local electric field. This measurement gives us a measure of the radial particle flux. We propose an active feedback system which attempts to suppress this turbulent radial transport via applying radial electric fields from a equatorial biasing array, as determined by the reference input from the 31-tip array. We also present results from a previously attempted method for observing bulk plasma motion through the imaging of mono- disperse dust particles. By tracking the particle trajectories, we can get measurements of acceleration, and therefore electric fields, in the interior of our plasma. In combining these diagnostics we hope to achieve a better understanding of turbulent transport in a dipole. This work is supported by U.S. DOE Grant DE-FG02-00ER54585.

  17. 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.

  18. Strongly intensive measures for particle number fluctuations: effects of hadronic resonances

    NASA Astrophysics Data System (ADS)

    Begun, Viktor V.; Gorenstein, Mark I.; Grebieszkow, Katarzyna

    2015-07-01

    The strongly intensive measures ? and ? are used to study event-by-event fluctuations of hadron multiplicities in nucleus–nucleus collisions. The effects of resonance decays are investigated using a statistical model and a relativistic transport model. Two specific examples are considered: resonance decays to two positively charged particles (e.g., {{? }++}\\to p+{{? }+}) and to {{? }+}{{? }-} pairs (e.g., {{? }0}\\to {{? }-}+{{? }+}). It is shown that resonance abundances at the chemical freeze-out can be estimated by measuring the fluctuations of the number of stable hadrons. These model results are compared against a full hadronresonance gas analysis within both the grand canonical and canonical ensembles. The ultra-relativistic quantum molecular dynamics (UrQMD) model of nucleus–nucleus collisions is used to illustrate the role of global charge conservation, centrality selection, and limited experimental acceptance.

  19. Millisecond measurement of transport during and after an electroporation pulse.

    PubMed Central

    Prausnitz, M R; Corbett, J D; Gimm, J A; Golan, D E; Langer, R; Weaver, J C

    1995-01-01

    Electroporation involves the application of an electric field pulse that creates transient aqueous pathways in lipid bilayer membranes. Transport through these pathways can occur by different mechanisms during and after a pulse. To determine the time scale of transport and the mechanism(s) by which it occurs, efflux of a fluorescent molecule, calcein, across erythrocyte ghost membranes was measured with a fluorescence microscope photometer with millisecond time resolution during and after electroporation pulses several milliseconds in duration. One of four outcomes was typically observed. Ghosts were: (1) partially emptied of calcein, involving efflux primarily after the pulse; (2) completely emptied of calcein, involving efflux primarily after the pulse; (3) completely emptied of calcein, involving efflux both during and after the pulse; or (4) completely emptied of calcein, involving efflux primarily during the pulse. Partial emptying, involving significant efflux during the pulse, was generally not observed. We conclude that under some conditions transport caused by electroporation occurs predominantly by electrophoresis and/or electroosmosis during a pulse, although under other conditions transport occurs in part or almost completely by diffusion within milliseconds to seconds after a pulse. PMID:7612828

  20. Measurements of Turbulent Transport of Fast Ions in the LAPD

    NASA Astrophysics Data System (ADS)

    Zhang, Y.; Boehmer, H.; Heidbrink, W. W.; McWilliams, R.; Zhao, L.; Carter, T.; Leneman, D.; Vincena, S.

    2004-11-01

    Understanding the spatial transport induced by fluctuations is important to the confinement of magnetized plasmas. The paradox of fast ions being much better confined than thermal ions, i.e. the effective diffusion coefficient of fast ions being much smaller than that of thermal ions, has been observed experimentally [1], explained theoretically [2], and analyzed by simulations [3]. Gyroradius averaging and drift averaging are two predicted effects that are responsible for reduced fast-ion transport. Our goal is to quantitatively confirm these effects and make further exploration by measuring fast-ion transport as a function of gyroradius in the LArge Plasma Device (LAPD) plasma with well-characterized background fluctuations. A 3D gridded analyzer is used to measure the spatial profile of the beam produced by an ion gun launching 500 eV Argon ions [4]. Strong drift wave fluctuations are generated by inserting a disk into the center of the plasma. First results will be presented. [1] W. Heidbrink, G. Sadler, Nucl. Fusion, Vol. 34, p. 535 (1994); [2] P. C. Efthimion et al., Plasma Phys. and Cont. Nucl. Fusion Res., Vol. 1, p. 307 (1988); [3] G. Manfredi, R. Dendy, Phys. Rev. Lett. 76, p. 4360 (1996); [4] H. Boehmer et al. , Rev. Sci. Instrum. , Vol. 75, p. 1013 (2002)

  1. 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.

  2. Separation bubbles at high Reynolds number: Measurement and computation

    NASA Astrophysics Data System (ADS)

    Devenport, William John

    1985-06-01

    Two flows through a sudden expansion in a pipe (an axisymmetric backward facing step) of area ratio 3.56, were studied experimentally. Both flows separated at the step, where the boundary layer was turbulent, and reattached to the pipe wall downstream enclosing a separation bubble. For one of the flows, a centerbody was mounted downstream of the step to provide an annular flow contraction and to impose a strong negative streamwise pressure gradient on the flow in the reattachment region. Both flows were effectively incompressible and of Reynolds number 1.5 x 10(exp 5). Pulsed-wire techniques were used to measure velocity and skin friction. A new pulsed-wire probe was developed to make detailed measurements of velocity in turbulent reversing flow between 0.15 mm and 0.55 mm from a wall. Without the centerbody, the bubble length was 10.7 step heights. For some distance downstream of the step the flow was in some ways similar to a free jet, though the shear layer grew at a slower rate and turbulence intensities were higher than in a jet. With the centerbody, the bubble length was 3.1 step heights. The separated shear layer was strongly curved towards its low-speed side by the centerbody. This had a stabilizing effect on turbulence in the layer. The shear layer approached the wall at a larger angle and was thinner in the reattachment region than it was without the centerbody. In both cases, the near-wall flow upstream of reattachment and in the attachment region was very different to that in a normal attached turbulent boundary layer. An inviscid empirically based computation method for flows with separation bubbles was developed. The flow is computed only on the high-speed side of the time-mean dividing streamline, the position of which is computed by specifying a static-pressure distribution along it. The effects of turbulence in the shear layer are modelled by specifying a distribution of stagnation pressure here, similar to that found in a fully-developed plane mixing layer. Several axisymmetric flows with separation bubbles were computed. The level of agreement with measurements is encouraging.

  3. Field measurements of tracer gas transport by barometric pumping

    SciTech Connect

    Lagus, P.L. [Lagus Applied Technology, San Diego, CA (United States); McKinnis, W.B. [Lawrence Livermore National Lab., Mercury, NV (United States); Hearst, J.R.; Burkhard, N.R.; Smith, C.F. [Lawrence Livermore National Lab., CA (United States)

    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.

  4. Local measurements of turbulent angular momentum transport in circular Couette flow

    NASA Astrophysics Data System (ADS)

    Burin, M. J.; Schartman, E.; Ji, H.

    2010-05-01

    We report on velocity fluctuations and the fluctuation-driven radial transport of angular momentum in turbulent circular Couette flow. Our apparatus is short (cylinder height to gap width ratio ? ~ 2) and of relatively high wall curvature (ratio of cylinder radii ? ~ 0.35). Fluctuation levels and the mean specific angular momentum are found to be roughly constant over radius, in accordance with previous studies featuring narrower gaps. Synchronized dual beam Laser Doppler Velocimetry (2D LDV) is used to directly measure the r - ? Reynolds stress component as a function of Reynolds number ( Re), revealing approximate scalings in the non-dimensional angular momentum transport that confirm previous measurements of torque in similar flows. 2D LDV further allows for a decomposition of the turbulent transport to assess the relative roles of fluctuation intensity and r - ? cross-correlation. We find that the increasing angular momentum transport with Re is due to intensifying absolute fluctuation levels accompanied by a slightly weakening cross-correlation.

  5. Fluorescence measurement of chloride transport in monolayer cultured cells. Mechanisms of chloride transport in fibroblasts.

    PubMed Central

    Chao, A C; Dix, J A; Sellers, M C; Verkman, A S

    1989-01-01

    The methodology has been developed to measure Cl activity and transport in cultured cells grown on a monolayer using the entrapped Cl-sensitive fluorophore 6-methoxy-N-[3-sulfopropyl] quinolinium (SPQ). The method was applied to a renal epithelial cell line, LLC-PKI, and a nonepithelial cell line, Swiss 3T3 fibroblasts. SPQ was nontoxic to cells when present for greater than h in the culture media. To load with SPQ (5 mM), cells were made transiently permeable by exposure to hypotonic buffer (150 mOsm, 4 min). Intracellular fluorescence was monitored continuously by epifluorescence microscopy using low illumination intensity at 360 +/- 5 nm excitation wavelength and photomultiplier detection at greater than 410 nm. Over 60 min at 37 degrees C, there was no photobleaching and less than 10% leakage of SPQ out of cells; intracellular SPQ fluorescence was uniform. SPQ fluorescence was calibrated against intracellular [Cl] using high K solutions containing the ionophores nigericin and tributyltin. The Stern-Volmer constant (Kq) for quenching of intracellular SPQ by Cl was 13 M-1 for fibroblasts and LLC-PKl cells. In the absence of Cl, SPQ lifetime was 26 ns in aqueous solution and 3.7 +/- 0.6 ns in cells, showing that the lower Kq in cells than in free solution (Kq = 118 M-1) was due to SPQ quenching by intracellular anions. To examine Cl transport mechanisms, the time course of intracellular [Cl] was measured in response to rapid Cl addition and removal in the presence of ion or pH gradients. In fibroblasts, three distinct Cl transporting systems were identified: a stilbeneinhibitable Cl/HCO3 exchanger, a furosemide-sensitive Na/K/2Cl cotransporter, and a Ca-regulated Cl conductance. These results establish a direct optical method to measure intracellular [Cl] continuously in cultured cells. Images FIGURE 2 PMID:2482083

  6. Fast device for large transport critical current measurements

    NASA Astrophysics Data System (ADS)

    D'Ovidio, Claudio A.; Esparza, Daniel A.; Malachevsky, Maria T.

    2002-08-01

    In this work we describe some modifications that improve an equipment for the fast measurement of transport critical currents in superconducting materials having a critical current of hundreds of amperes. It is based on the appliance of an electrical current for a very short period of time, rapid enough to preserve the integrity of the current leads and minimize the Joule effect. Power is applied to the wire-sample ensemble and the voltage drop is measured within seconds, with a resolution that can reach the order of 10 nV. The hardware is composed of three parts: the current pulse generator, a low noise-quick response differential voltage amplifier and a PC with a digital to analog converter-analog to digital converter card. The data acquisition is achieved via an Assembler program.

  7. Measurements of Classical Transport of Fast Ions in the LAPD

    NASA Astrophysics Data System (ADS)

    Zhao, L.; Boehmer, H.; Edrich, D.; Heidbrink, W. W.; McWilliams, R.; Zimmerman, D.; Lenenman, D.; Vincena, S.

    2004-11-01

    To study fast ion transport in a well controlled background plasma, a 3cm diameter RF ion gun launches a pulsed, 400 eV ribbon shape argon ion beam in the LArge Plasma Device (LAPD) at UCLA. The beam velocity distribution is calibrated by Laser Induced Fluorescence (LIF) on the Mirror of UCI and the beam energy is also measured by a two-grid energy analyzer at different axial locations (z=0.3-6.0 m) from the source on LAPD. Slowing down of the ion beam is observed when the beam is launched parallel or at 15 degrees to the 0.85 kG magnetic field. Using Langmuir probe measurements of the plasma parameters, the observed energy deceleration rate is consistent with classical Coulomb scattering theory. The radial beam profile is also measured by the energy analyzer when the beam is launched at 15 degrees to the magnetic field. The beam follows the expected helical trajectory and its contour has the shape predicted by Monte Carlo simulations. The diffusion measurements are performed at different axial locations where the ion beam has the same gyro-phase to eliminate the peristaltic effect. The spatial spreading of the beam is compared with classical scattering and neutral scattering theory.

  8. 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.

  9. Bidirectional transepithelial water transport: measurement and governing mechanisms.

    PubMed Central

    Phillips, J E; Wong, L B; Yeates, D B

    1999-01-01

    In the search for the mechanisms whereby water is transported across biological membranes, we hypothesized that in the airways, the hydration of the periciliary fluid layer is regulated by luminal-to-basolateral water transport coupled to active transepithelial sodium transport. The luminal-to-basolateral (JWL-->B) and the basolateral-to-luminal (JWB-->L) transepithelial water fluxes across ovine tracheal epithelia were measured simultaneously. The JWL-->B (6.1 microliter/min/cm2) was larger than JWB-->L (4.5 microliter/min/cm2, p < 0.05, n = 30). The corresponding water diffusional permeabilities were PdL-->B = 1.0 x 10(-4) cm/s and PdB-->L = 7.5 x 10(-5) cm/s. The activation energy (Ea) of JWL-->B (11.6 kcal/mol) was larger than the Ea of JWB-->L (6.5 kcal/mol, p < 0.05, n = 5). Acetylstrophanthidin (100 microM basolateral) reduced JWL-->B from 6.1 to 4.4 microliter/min/cm2 (p < 0. 05, n = 5) and abolished the PD. Amiloride (10 microM luminal) reduced JWL-->B from 5.7 to 3.7 microliter/min/cm2 (p < 0.05, n = 5) and reduced PD by 44%. Neither of these agents significantly changed JWB-->L. These data indicate that in tracheal epithelia under homeostatic conditions, JWB-->L was dominated by diffusion (Ea = 4.6 kcal/mol), whereas approximately 30% of JWL-->B was coupled to the active Na+,K+-ATPase pump (Ea = 27 kcal/mol). PMID:9929488

  10. Numbers

    NSDL National Science Digital Library

    2013-06-14

    The purpose of this video tutorial is to review a couple ways in which we think about numbers. Thinking in terms of street numbers, money in bank accounts, and quantum particles (e.g. Bose-Einstein condensate) is contrasted with focusing on associating numbers with distinguishable manipulatives, as is more familiar in K-8 courses. This video concludes with a reminder that the symbol "infinity" is not, itself, a number.

  11. Creation, Transport and Measurement of Bright Relativistic Electron Beams.

    NASA Astrophysics Data System (ADS)

    McKee, Chad Bennett

    This thesis deals with three topics relevant to linac-driven free electron lasers: the creation, transport and measurement of bright relativistic electron beams. Thermionic microwave electron guns produce bright electron beams that are well suited to drive free electron lasers, FELs. The rf fields in the gun cause some of the emitted electrons to reverse direction and strike the cathode. These back-bombarding electrons heat the cathode limiting both the pulse length and time averaged current. The cathode heating is reduced if a transverse magnetic field is applied across the gun cavity to deflect back-bombarding electrons. We improve the thermionic microwave electron gun by redesigning the deflection magnet to minimize the back-heating power. Computer simulations show that transverse magnetic fields with rapid axial falloffs reduce the back-heating power more than fields that are axially constant. Experiments verify these simulations. The deflection magnet presently installed on the Mark III gun has a slow axial falloff and reduces the back-heating power by 31%. Using the simulation results we design a new deflection magnet having a rapid axial falloff. This magnet has been installed on the NCCU gun and reduces the back-heating power by 63%. Improper transport of the electron beam through the beam line degrades the quality of the electron beam and lowers the performance of the FEL. We propose to improve the beam line commissioning and control procedures on linac -driven FELs by experimentally measuring the transfer matrix of each beam line section. The transfer matrix of a given section is measured by dithering the electron beam, measuring the beam vector before and after the section and inverting the subsequent data matrix. We minimize the beam line errors by minimizing the deviation between the experimentally measured transfer matrix and the design transfer matrix of each beam line section. While not experimentally verified, computer simulations show that this technique can be very effective in bringing the experimental beam line close to its design specifications. The performance of an FEL depends on various characteristics of the electron beam used to drive it. The gain of the laser especially depends on the transverse phase space distribution of the electrons. Previously it has not been possible to measure the details of the transverse phase space distribution of high-energy electron beams with the precision required to predict FEL performance. Standard techniques for measuring the transverse phase space of relativistic electron beams treat the phase space distributions as ellipses and only measure the sigma matrices that define the ellipses. These techniques give no information about the detailed structure of the phase space distributions. We have developed a new technique to measure transverse phase space that combines quadrupole-scanning techniques with tomographic image reconstruction to measure the actual phase space distributions while making no a priori assumptions about the distributions. Using this process, we are able to reconstruct phase space distributions that are not elliptical. Both computer simulations and experiments verify that phase space tomography makes the detailed measurement of the phase space distributions possible at high energies. Detailed reconstructions of the phase space distribution of a 44 MeV electron beam from the Mark III FEL are presented.

  12. 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.

  13. LIF diagnostic for measuring beam transport magnetic fields

    SciTech Connect

    Jones, T.G.; Noonan, W.A.; Ottinger, P.F. [Naval Research Lab., Washington, DC (United States). Plasma Physics Div.

    1997-12-31

    A novel, spatially-resolved, non-intrusive diagnostic is being developed to measure magnetic fields associated with intense ion beam propagation through a low-pressure gas, as is envisioned for light ion-driven ICF. The diagnostic uses laser-induced fluorescence (LIF), and is varied to measure either small or large fields. Small fields (B < 200 G), as expected in ballistic transport with solenoidal lens focusing using 1 Torr gas, produce Zeeman shifts, {Delta}{lambda}{sub z}, smaller than the transition linewidth, {Delta}{lambda}. High sensitivity for the low-B measurement is achieved by a variation on the Babcock technique using LIF spectroscopy. LIF from a J = 1{r_arrow}0 transition in a probe species is viewed parallel to B. In this case {Delta}M=0 fluorescence is not visible, and {Delta}M={+-}1 fluorescence is right- and left-circularly polarized, and can be measured separately using polarization filters. If a narrow-bandwidth pump laser is tuned to a half-maximum point of the unsplit transition line, the B-field shifts one of the {Delta}M={+-}1 absorption transitions into resonance with the laser and shifts the other further out of resonance. For small fields, the difference in the fluorescence signals of the two polarization is proportional to {Delta}{lambda}{sub z} and B. Large fields (B > 200 G), as expected in self-pinched transport using 10 to 100 mTorr gas, produce {Delta}{lambda}{sub z} larger than {Delta}{lambda}. The small-B technique can be adapted to measure large B by adding an etalon to act as a narrow-band optical filter of LIF. The etalon transmission curve then transduces {Delta}{lambda}{sub z} to a change in detected intensity, analogously to the absorption line profile in the small-B technique. Results of proof-of-principle experiments using calibrated B-fields, and plans for fielding the diagnostic on Gamble-II are presented.

  14. Numbers

    NSDL National Science Digital Library

    Jo Edkins

    2006-01-01

    This engaging web site contains information and interactive applets related to various number systems: Egyptian, Babylonian, Chinese, Greek, Roman, Mayan, and Arabic. Users learn the history and structure of each system as well as how to count and write numbers. The site also allows users to explore finger systems, calculating machines, other number bases, and "interesting numbers." A series of pages on data and graphs includes information and activities on gathering, analyzing, graphing and sorting data. (Because the section on the Arabic number system is so extensive, it is cataloged separately as a related resource.)

  15. A Measurement of the Information Value in Transport Processes

    NASA Astrophysics Data System (ADS)

    Wydro, Kornel B.

    The problem of the cost/benefit evaluation at ITS implementation stands for one of the key questions during the system planning. As all the intelligent transport systems are based on the intensive exploitation of information, the question of information value is of a significant meaning. One approaches the problem in a various manners, mostly yet by calculation of the economic effects "post factum". But this method is of low convenience and usefulness, as it may rely mostly on the experience, which brings always some errors resulted by the solutions and circumstances uniqueness. In the paper there are discussed evaluation approaches based on subjective value assessment and probabilistic decision model, in which a value of information is measured as the effect of it influence on decision choice, with considering the probabilities of a given decision circumstances. Obviously, this method have to be applied "ante-factum".

  16. Infrared measuring equipment with a limited number of communication channels

    Microsoft Academic Search

    A. S. Moiseenko; A. P. Orlov; L. Z. Pozin; P. F. Puzyrev; É. Kh. Asatryan

    1973-01-01

    A borehole telemetering equipment was produced in 1965 for investigating thermal fields by means of infrared (heat) radiation detectors. The heat exchange of this equipment's transducers with the surrounding medium was accomplished by means of a contactless radiation method [1, 2, 5]. In designing this equipment there arise several specific problems due to the limitation of the number of communication

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

    PubMed

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

    2013-11-30

    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

  18. 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…

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

    PubMed

    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. PMID:26001981

  20. 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

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

    Microsoft Academic Search

    Dieter Rickenmann; Jens Turowski; Ramon Hegglin; Bruno Fritschi

    2010-01-01

    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

  2. Measuring regional cohesion effects of large-scale transport infrastructure investments - an accessibility approach

    Microsoft Academic Search

    Elena Lopez

    2005-01-01

    Accessibility gains arising from transport infrastructure improvements are one of the key elements boosting a complex process involving transport, land use and regional development effects. The inclusion of the wider socio-economic effects stemming from large-scale transport infrastructure investments is uneven among national evaluation procedures, and there is no commonly accepted methodology to measure them. In addition, there are other effects

  3. 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.

  4. Prediction and measurement of thermal transport across interfaces between isotropic solids and graphitic materials.

    SciTech Connect

    Hopkins, Patrick E.; Norris, Pamela M. (University of Virginia Charlottesville, VA); Smoyer, Justin L. (University of Virginia Charlottesville, VA); Duda, John C. (University of Virginia Charlottesville, VA)

    2010-06-01

    Due to the high intrinsic thermal conductivity of carbon allotropes, there have been many attempts to incorporate such structures into existing thermal abatement technologies. In particular, carbon nanotubes (CNTs) and graphitic materials (i.e., graphite and graphene flakes or stacks) have garnered much interest due to the combination of both their thermal and mechanical properties. However, the introduction of these carbon-based nanostructures into thermal abatement technologies greatly increases the number of interfaces per unit length within the resulting composite systems. Consequently, thermal transport in these systems is governed as much by the interfaces between the constituent materials as it is by the materials themselves. This paper reports the behavior of phononic thermal transport across interfaces between isotropic thin films and graphite substrates. Elastic and inelastic diffusive transport models are formulated to aid in the prediction of conductance at a metal-graphite interface. The temperature dependence of the thermal conductance at Au-graphite interfaces is measured via transient thermoreflectance from 78 to 400 K. It is found that different substrate surface preparations prior to thin film deposition have a significant effect on the conductance of the interface between film and substrate.

  5. 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. [Kavli Institute for Particle Astrophysics and Cosmology, Stanford University, 2575 Sand Hill Road M/S 29, Menlo Park, CA 94025 (United States); Mac Low, Mordecai-Mark, E-mail: jsoishi@stanford.edu, E-mail: mordecai@amnh.org [Department of Astrophysics, American Museum of Natural History, Central Park West at 79th Street, New York, NY 10024 (United States)

    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.

  6. 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.; /KIPAC, Menlo Park; 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.

  7. 41 CFR 102-117.270 - What are agency performance measures for transportation?

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...and set up program performance measures. (b) Examples of performance measurements in transportation would include how well you: (1) Increase the use of electronic commerce; (2) Adopt industry best practices and services to meet...

  8. 41 CFR 102-117.270 - What are agency performance measures for transportation?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...and set up program performance measures. (b) Examples of performance measurements in transportation would include how well you: (1) Increase the use of electronic commerce; (2) Adopt industry best practices and services to meet...

  9. 41 CFR 102-117.270 - What are agency performance measures for transportation?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...and set up program performance measures. (b) Examples of performance measurements in transportation would include how well you: (1) Increase the use of electronic commerce; (2) Adopt industry best practices and services to meet...

  10. 41 CFR 102-117.270 - What are agency performance measures for transportation?

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...and set up program performance measures. (b) Examples of performance measurements in transportation would include how well you: (1) Increase the use of electronic commerce; (2) Adopt industry best practices and services to meet...

  11. 41 CFR 102-117.270 - What are agency performance measures for transportation?

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...and set up program performance measures. (b) Examples of performance measurements in transportation would include how well you: (1) Increase the use of electronic commerce; (2) Adopt industry best practices and services to meet...

  12. VOLUME 60, NUMBER 20 PHYSICAL REVIEW LETTERS 16 MAY 1988 Mass Transport in Propagating Patterns of Convection

    E-print Network

    Moses, Elisha

    of Convection Elisha Moses Department of Physics, Weizmann Institute, Rehovot, Israel and Victor Steinberg observation of convective transport in oscillatory convection of a binary mixture. The results show. PACS numbers: 47.25.Jn Extensive studies of oscillatory convection in binary mixtures have recently

  13. 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.

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

    SciTech Connect

    Portsmouth, J.H. [Westinghouse Hanford Co., Richland, WA (United States)

    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.

  15. Indicators that matter : measuring transportation performance in Ahmedabad

    E-print Network

    Osborne, James Clark, M.C.P. Massachusetts Institute of Technology

    2012-01-01

    In light of the growing challenges of planning for transportation in India, this thesis proposes that a set of indicators, sensitive to local conditions, developed, implemented and managed through a collaborative partnership ...

  16. 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.

  17. Application of electrochemical impedance measurements to corrosion prediction in the space transportation system launch environment

    SciTech Connect

    Calle, L.M. [Randolph-Macon Woman`s College, Lynchburg, VA (United States); MacDowell, L.G. III [NASA Materials Science Lab., Kennedy Space Center, FL (United States)

    1994-12-31

    Electrochemical Impedance Spectroscopy (EIS) measurements were performed to investigate the corrosion resistance of 18 alloys under conditions similar to the Space Transportation System (STS) launch environment. The UNS numbers of the alloys used were: R60702, N06022, N06625, N10276, N06455, N06600, S32950, S32550, N06985, N08020, N08904, N08825, S31603, S31703, S31803, S30403, N10665, and N04400. AC impedance data were gathered for all the alloys at various immersion tunes in aerated 3.55% NaCl-0.1N HCl. This electrolyte provides an environment for the corrosion of the alloys similar to conditions at the launch pad. Polarization resistance values were obtained from the Nyquist plot at each immersion time by curve fitting methods. N06022 showed the highest overall values for R{sub p} while N04400 and N06600 had the lowest overall values.

  18. Predicting the vertical distribution of particle number concentration using the 3-D regional CTM PMCAMx-UF: relevance of high altitude nucleation and transport and cloud properties

    NASA Astrophysics Data System (ADS)

    Baranizadeh, Elham; Murphy, benjamin; Ahlm, Lars; Fountoukis, Christos; Pandis, Spyros; Virtanen, Annele; Lehtinen, Kari; Laaksonen, Ari; Riipinen, Ilona

    2015-04-01

    The three-dimensional chemical transport model PMCAMx-UF was used to predict the aerosol number concentrations (N) over the Europe domain during May 2008. We implemented the more sophisticated approach called Tropospheric Ultra-Violet and Visible (TUV) radiative transfer model (NCAR, 2011) to treat the cloud effect on photolysis rates. The changes in Sulfuric Acid and particles number concentrations anticorrelate at the ground level (and below clouds) while correlate above clouds. This is because updated version of the model including TUV module simulates higher radiation above the clouds resulting in stronger new particle formation in higher altitudes which are eventually transported to lower levels. For example, mean-percent-differences are 9 and -41 % in N3 and H2SO4, respectively, below clouds (cloudy regions with cloud optical depth ? >50 was chosen) and 12 and 210 % above cloud at May 5, 2008 12:00 UTC. The vertical profiles of particle number concentrations were evaluated against the measured data from EUCAARI-LONGREX campaign. Results indicate that the model is slightly overestimating the particles in nucleation mode range over the ground-level altitudes. However, the model shows a significant agreement with the measurements for the N4 (i.e. particles larger than 4 nm) and also N10 over all altitude levels.

  19. Shack Hartmann wave-front measurement with a large F-number plastic microlens array

    E-print Network

    Yoon, Geunyoung

    Shack Hartmann wave-front measurement with a large F-number plastic microlens array Geun Young Yoon, with a constant peak intensity. One can improve the wave-front measurement accuracy by reducing the spot the wave-front sensor gives an appropriate defocus and astigmatism, and the laser wave front is measured

  20. Volume 150, number 5 CHEMICAL PHYSICS LETTERS 23 September 1988 SURFACE TEMPERATURE MEASUREMENT OF DIELECTRIC MATERIALS

    E-print Network

    Zare, Richard N.

    Volume 150, number 5 CHEMICAL PHYSICS LETTERS 23 September 1988 SURFACE TEMPERATURE MEASUREMENT The temperature of a dielectric surface irradiated by a laser pulse can be measured by recording the time report here a new method to measure the tran- sient surface temperature induced by pulsed laser ir

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

    SciTech Connect

    NONE

    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.

  2. Terahertz magneto-transport measurements in underdoped PCCO and comparison with ARPES

    Microsoft Academic Search

    G. S. Jenkins; D. C. Schmadel; P. L. Bach; R. L. Greene; X. Bechamp-Laganiere; G. Roberge; P. Fournier; H. D. Drew

    2009-01-01

    We present magneto-transport measurements performed on underdoped PCCO at THz\\u000afrequencies as a function of temperature and doping. A rapidly decreasing Hall\\u000amass is observed as the doping is reduced consistent with the formation of\\u000asmall electron Fermi pockets. However, both dc and infrared (IR)\\u000amagneto-transport data strongly deviate from the predictions of transport\\u000atheory in the relaxation time approximation

  3. MOBILITY MEASUREMENT IN URBAN TRANSPORTATION (MMUT) RESEARCH PROJECT

    E-print Network

    techniques such as cell phone tracking and global position satellite tracking are being used to gather phone tracking, global position satellite tracking, and on-board navigation devices. Some issues monitoring and transportation planning. These new and emerging data sources include such technologies as cell

  4. Measurement of the Lateral Transport Current Distribution in YBCO Tape

    Microsoft Academic Search

    Pavol Usak; Milan Polak; Pavol Mozola

    2009-01-01

    Hall probe mapping was applied to the self-field of the YBCO superconducting tape with gradually increasing and decreasing transport current. The mapped data of magnetic field component perpendicular to the tape plane were used in inverse calculation of the lateral current distribution across the width of the tape for different current levels. The concept of longitudinal invariance of current distribution

  5. Acoustical and optical backscatter measurements of sediment transport in the 1988 1989 STRESS experiment

    NASA Astrophysics Data System (ADS)

    Lynch, J. F.; Gross, T. F.; Sherwood, C. R.; Irish, J. D.; Brumley, B. H.

    1997-04-01

    During the 1988-1989 Sediment Transport Events on Shelves and Slopes (STRESS) experiment, a 1-MHz acoustic backscatter system (ABSS), deployed in 90 m of water off the California coast measured vertical profiles of suspended sediment concentration from 1.5 to (nominally) 26 meters above bottom (m.a.b.). An 8-week-long time series was obtained, showing major sediment transport events (storms) in late December and early January. Comparison of the acoustics measurements from 1.5 m.a.b. are made with optical backscatter system (OBS) concentration estimates lower in the boundary layer (0.25 m.a.b.). Correlations between ABSS and OBS concentration measurements and the boundary layer forcing functions (waves, currents, and their non-linear interaction) provided a variety of insights into the nature of the sediment transport of the STRESS site. Transport rates and integrated transport are seen to be dominated by the largest storm events.

  6. 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=2098?g/L and REI-SD=2048?g/L) reduced groundwater P concentrations above the Bh horizon by 33% compared to HEI (3090?g/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

  7. 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 ?g/L and REI-SD = 2048 ?g/L) reduced groundwater P concentrations above the Bh horizon by 33% compared to HEI (3090 ?g/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.

  8. 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.

  9. Correlation between oxygen status measures during neonatal air transport

    Microsoft Academic Search

    Susan J. Squire

    1997-01-01

    Introduction: The purpose of this study was to determine the strength of the relationship between arterial oxygen tension (Pao2) and transcutaneous oxygen (Ptco2), and arterial carbon dioxide tension (Paco2) and transcutaneous carbon dioxide (Ptcco2) of premature neonates during fixed-wing air transport.Method: The study admitted 37 randomly selected intubated or nonintubated neonates who received oxygen by mechanical ventilation or face mask

  10. Measuring the evolution of transport protocols in the internet

    Microsoft Academic Search

    Alberto Medina; Mark Allman; Sally Floyd

    2005-01-01

    In this paper we explore the evolution of both the Internet's most heavily used transport protocol, TCP, and the current network environment with respect to how the network's evolution ultimately impacts end-to-end protocols. The traditional end-to-end assumptions about the Internet are increasingly challenged by the introduction of intermediary network elements (middleboxes) that intentionally or unintentionally prevent or alter the behavior

  11. Anharmonic effects on a phonon-number measurement of a quantum-mesoscopic-mechanical oscillator

    SciTech Connect

    Santamore, D.H.; Goan Hsisheng; Milburn, G.J.; Roukes, M.L. [ITAMP, Harvard-Smithsonian Center for Astrophysics, Cambridge, Massachusetts 02138 (United States); Department of Physics, Harvard University, Cambridge, Massachusetts 02138 (United States); Department of Physics, California Institute of Technology, Pasadena, California 91125 (United States); Centre for Quantum Computer Technology, University of New South Wales, Sydney, New South Wales 2052 (Australia); Centre for Quantum Computer Technology, University of Queensland, St. Lucia, Queensland 4072 (Australia); Condensed Matter Physics, California Institute of Technology, Pasadena, California 91125 (United States)

    2004-11-01

    We generalize a proposal for detecting single-phonon transitions in a single nanoelectromechanical system (NEMS) to include the intrinsic anharmonicity of each mechanical oscillator. In this scheme two NEMS oscillators are coupled via a term quadratic in the amplitude of oscillation for each oscillator. One NEMS oscillator is driven and strongly damped and becomes a transducer for phonon number in the other measured oscillator. We derive the conditions for this measurement scheme to be quantum limited and find a condition on the size of the anharmonicity. We also derive the relation between the phase diffusion back-action noise due to number measurement and the localization time for the measured system to enter a phonon-number eigenstate. We relate both these time scales to the strength of the measured signal, which is an induced current proportional to the position of the read-out oscillator.

  12. 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.

  13. 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

  14. Distance-based functional diversity measures and their decomposition: a framework based on Hill numbers.

    PubMed

    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

  15. Transport measurements on magnetically coupled superconductor-2D-electron-gas hybrids

    E-print Network

    Nabben, Reinhard

    Transport measurements on magnetically coupled superconductor-2D-electron-gas hybrids H Scheel, A R measurements on magnetically coupled superconductor-2D-electron-gas hybrids 2 oscillations being a property the electron gas formed in the quantum well. These measurements demonstrate that filamentary and channel vortex

  16. Measurements of the production and transport of helium ash in the TFTR tokamak

    Microsoft Academic Search

    E. J. Synakowski; R. E. Bell; R. V. Budny; C. E. Bush; P. C. Efthimion; B. Grek; D. W. Johnson; L. C. Johnson; B. Leblanc; A. T. Ramsey; G. Taylor

    1995-01-01

    Helium ash production and transport have been measured in TFTR deuterium-tritium plasmas using charge-exchange recombination spectroscopy. The helium ash confinement time, including recycling effects, is 6-10 times the energy confinement time and is compatible with sustained ignition in a reactor. The ash confinement time is dominated by edge pumping rates rather than core transport. The measured evolution of the local

  17. 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.

  18. Estimating the number of frequency hopping interferers using spectral sensing with time and frequency offset measurements

    Microsoft Academic Search

    A. Gok; Shaunak Joshi; John Villasenor; Danijela Cabric

    2009-01-01

    A critical aspect of spectrum sensing involves determining the number and type of transmitters in the band of interest. We present a technique that exploits a combination of temporal and frequency-based analysis to enable significantly more accurate frequency offset measurements than would be possible with frequency domain measurements alone, thus enabling improved RF fingerprinting for frequency hopping devices.

  19. Quantum correlations cannot arise from measurements with limited number of outcomes

    E-print Network

    Matthias Kleinmann; Adan Cabello

    2015-06-02

    There is a tension in quantum theory between the existence of a widely accepted way to axiomatize the theory and the lack of similarly accepted intuitive principles from which the theory can be derived. This tension is present at the very definition of what measurements are admissible. The usual assumption is that all measurements which do not produce negative probabilities are valid measurements, irrespective of how many outcomes the measurement has. Here we show that this assumption is accessible to falsification by particular high-precision Bell-type experiments, which can exclude that all measurements are produced from measurements with a limited number of outcomes and classical measurements. Our analysis reveals that the results of previous experiments provide evidence that nature cannot be explained with the simplest of these modifications in which quantum measurements are limited to two or three outcomes. This supports standard quantum theory versus some natural and almost indistinguishable alternatives. Future experiments can also aim to exclude other alternatives such as quantum measurements with higher number of outcomes and more general non-signaling theories with a limited number of outcomes, possibly imposing universal constraints on the structure of measurements in any physical theory.

  20. Measuring the part worth of the mode of transport in a trip package: An extended Bradley–Terry model for paired-comparison conjoint data

    Microsoft Academic Search

    Reinhold Hatzinger; Josef A. Mazanec

    2007-01-01

    This study measures the travelers' perceived change in utility by accepting one of the modes of transport air, rail, or bus as one component of a packaged city trip. The part-worth values for the trip product elements are expected to depend on a number of traveler characteristics. The predictors hypothesized are city travel experience, general modal preference, socio-economic status, and

  1. 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.

  2. FTEStaff/StudentNumbers University of Bath 2012 Transport Baseline Report Executive Summary

    E-print Network

    Burton, Geoffrey R.

    and the results reported in March 2013. The 2012 Baseline Report summarises current transport conditions Motor cycle Total MovementsSole Occ With Pass TOT 2007 29.7% 7.7% 37.4% 9.9% 45.1% 4.9% 1.9% 0.8% 15 this suggests that there is greater demand for travel to the Campus. Graph 1.2 below takes the modal share data

  3. Resonant Acoustic Measurement of Vapor Phase Transport Phenomenon

    Microsoft Academic Search

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

    2002-01-01

    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

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

    SciTech Connect

    Efthimion, P.C.; Johnson, L.C.; Skinner, C.H. [Princeton Univ., NJ (United States). Plasma Physics Lab.] [and others

    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.

  5. 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).

  6. 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 (u?), 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 u?. 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.

  7. 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.

  8. 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.

  9. 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

    ...2013-07-01 false Test Concentration Ranges, Number of Measurements Required, and...Subpart C of Part 53—Test Concentration Ranges, Number of Measurements Required, and...Specifications Pollutant Concentration range, parts per million (ppm)...

  10. 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

    ...2012-07-01 false Test Concentration Ranges, Number of Measurements Required, and...Subpart C of Part 53—Test Concentration Ranges, Number of Measurements Required, and...Specifications Pollutant Concentration range, parts per million (ppm)...

  11. 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

    ...2014-07-01 false Test Concentration Ranges, Number of Measurements Required, and...Subpart C of Part 53—Test Concentration Ranges, Number of Measurements Required, and...Specifications Pollutant Concentration range, parts per million (ppm)...

  12. 40 CFR Table C-1 to Subpart C of... - Test Concentration Ranges, Number of Measurements Required, and Maximum Discrepancy Specification

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...2010-07-01 2010-07-01 false Test Concentration Ranges, Number of Measurements Required...C-1 to Subpart C of Part 53—Test Concentration Ranges, Number of Measurements Required...Discrepancy Specification Pollutant Concentration range, parts permillion...

  13. Measurement of transference numbers for lithium ion electrolytes via four different methods, a comparative study

    Microsoft Academic Search

    S. Zugmann; M. Fleischmann; M. Amereller; R. M. Gschwind; H. D. Wiemhöfer; H. J. Gores

    2011-01-01

    We report here on comparative measurements of cationic transference numbers of some lithium battery related electrolytes including lithium tetrafluoroborate in propylene carbonate, lithium hexafluorophosphate in blends of ethylene carbonate\\/diethyl carbonate and ethylene carbonate\\/propylene carbonate\\/dimethyl carbonate, as well as lithium difluoromono (oxalate) borate in an ethylene carbonate\\/diethyl carbonate blend via four different methods. Whereas three electrochemical methods yield transference numbers decreasing

  14. Measurement of DNA Copy Number at Microsatellite Loci Using Quantitative PCR Analysis

    Microsoft Academic Search

    David G. Ginzinger; Tony E. Godfrey; Janice Nigro; Dan H. Moore; Seiji Suzuki; Maria G. Pallavicini; Joe W. Gray; Ronald H. Jensen

    2000-01-01

    This report describes the development and validation of quantitative microsatellite analysis (QuMA) for rapid measurement of relative DNA sequence copy number. In QuMA, the copy number of a test locus relative to a pooled reference is assessed using quantitative, real-time PCR am- plification of loci carrying simple sequence repeats. Use of simple sequence repeats is advantageous because of the large

  15. Tabulated pressure measurements on a large subsonic transport model airplane with high bypass ratio, powered, fan jet engines

    NASA Technical Reports Server (NTRS)

    Flechner, S. G.; Patterson, J. C., Jr.

    1972-01-01

    An experimental wind-tunnel investigation to determine the aerodynamic interference and the jet-wake interference associated with the wing, pylon, and high-bypass-ratio, powered, fan-jet model engines has been conducted on a typical high-wing logistics transport airplane configuration. Pressures were measured on the wing and pylons and on the surfaces of the engine fan cowl, turbine cowl, and plug. Combinations of wing, pylons, engines, and flow-through nacelles were tested, and the pressure coefficients are presented in tabular form. Tests were conducted at Mach numbers from 0.700 to 0.825 and angles of attack from -2 to 4 deg.

  16. 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.

  17. In situ measurements of colloid transport and retention using synchrotron X-ray fluorescence

    E-print Network

    Walter, M.Todd

    In situ measurements of colloid transport and retention using synchrotron X-ray fluorescence David] The physics regarding the retention and mobilization of colloids in saturated and unsaturated conditions remains poorly understood, partially because of the inability to measure colloid concentrations in situ

  18. Using a qubit to measure photon number statistics of a driven, thermal oscillator

    E-print Network

    A. A. Clerk; D. Wahyu Utami

    2006-12-09

    We demonstrate theoretically how photon number statistics of a driven, damped oscillator at finite temperature can be extracted by measuring the dephasing spectrum of a two-level system dispersively coupled to the oscillator; we thus extend the work of Dykman (1987) and Gambetta et al. (2006). We carefully consider the fidelity of this scheme-- to what extent does the measurement reflect the initial number statistics of the mode? We also derive analytic results for the dephasing of a qubit by a driven, thermal mode, and compare results obtained at different levels of approximation. Our results have relevance both to experiments in circuit cavity QED, as well as to nano-electromechanical systems.

  19. Noise detection and transport measurements of spin valve systems

    NASA Astrophysics Data System (ADS)

    Guo, Feng

    Electronic noise not only limits the performance of magnetic devices in practical applications but also provides valuable physical insights into these devices. The first part of this thesis discusses how the low frequency noise in magnetic tunnel junctions and giant magnetoresistance devices can be used to understand the fundamental noise sources. Previously, the low frequency noise in these systems has been reported to have an enormously large magnitude when the magnetization switches. This was attributed to magnetic fluctuations. An alternative mechanism of a slow drift in the device resistance is discussed, and we show how it produces noise spectra that are similar to those in previous reports. We conclude that this resistance drift causes a measurement artifact and the low frequency magnetic noise is not present in the measured samples within measurement error. As a second part of the thesis, we discuss a pronounced voltage dependent conductance feature present at nonzero bias in some magnetic tunnel junctions. The presence of this feature depends upon the oxidation condition for creating the barrier, and this effect is found to be interfacial in nature. We describe how the electronic structures and density of states at the barrier interfaces could be responsible for this effect, and possibility of utilizing the conductance measurement to probe the interfacial states.

  20. 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...

  1. 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...

  2. GOODNESS DEFINITION AND GOODNESS MEASURE FOR HIGH SPEED TRANSPORT PROTOCOLS FOR LIGHTWEIGHT NETWORKING APPLICATIONS

    Microsoft Academic Search

    Isil Sebuktekin

    1992-01-01

    Recent advances in optical communications, VLSI, and fiber-optic technologieshave created new horizons for high-speed protocols and applicationsseeking end-to-end data transport at Gb\\/s speeds. In this Ph.D dissertation, anitemized goodness definition consisting of six criteria is presented for evaluationof high speed transport protocols used in lightweight networking applications.Based on this goodness definition, a goodness measure is also defined in thisdissertation to

  3. The association between objectively measured neighbourhood features and walking for transport in mid-aged adults

    Microsoft Academic Search

    Lee-Ann Wilson; Billie Giles-Corti; Gavin Turrell

    2012-01-01

    The aim of this paper is to examine the association between a range of objectively measured neighbourhood features and the likelihood of mid-aged adults walking for transport. Increased walking for transport would bring multiple benefits, including improved population and environmental health. As part of the baseline HABITAT study, 10,745 residents of Brisbane, Australia, aged 40–65 years, from 200 neighbourhoods were

  4. Effects of droplet interactions on droplet transport at intermediate Reynolds numbers

    NASA Technical Reports Server (NTRS)

    Shuen, J. S.

    1986-01-01

    Effects of droplet interactions on drag, evaporation, and combustion of a planar droplet array, oriented perpendicular to the approaching flow, are studied numerically. The three-dimensional Navier-Stokes equations, with variable thermophysical properties, are solved using finite-difference techniques. Parameters investigated include the droplet spacing, droplet Reynolds number, approaching stream oxygen concentration, and fuel type. Results are obtained for the Reynolds number range of 5 to 100, droplet spacing from 2 to 24 diameters, oxygen concentrations of 0.1 and 0.2, and methanol and n-butanol fuels. The calculations show that the gasification rates of interacting droplets decrease as the droplet spacings decrease. The reduction in gasification rates is significant only at small spacings and low Reynolds numbers. For the present array orientation, the effects of interactions on the gasification rates diminish rapidly for Reynolds numbers greater than 10 and spacings greater than 6 droplet diameters. The effects of adjacent droplets on drag are shown to be small.

  5. Effects of droplet interactions on droplet transport at intermediate Reynolds numbers

    NASA Technical Reports Server (NTRS)

    Shuen, Jian-Shun

    1987-01-01

    Effects of droplet interactions on drag, evaporation, and combustion of a planar droplet array, oriented perpendicular to the approaching flow, are studied numerically. The three-dimensional Navier-Stokes equations, with variable thermophysical properties, are solved using finite-difference techniques. Parameters investigated include the droplet spacing, droplet Reynolds number, approaching stream oxygen concentration, and fuel type. Results are obtained for the Reynolds number range of 5 to 100, droplet spacings from 2 to 24 diameters, oxygen concentrations of 0.1 and 0.2, and methanol and n-butanol fuels. The calculations show that the gasification rates of interacting droplets decrease as the droplet spacings decrease. The reduction in gasification rates is significant only at small spacings and low Reynolds numbers. For the present array orientation, the effects of interactions on the gasification rates diminish rapidly for Reynolds numbers greater than 10 and spacings greater than 6 droplet diameters. The effects of adjacent droplets on drag are shown to be small.

  6. Wind tunnel investigation of an oblique wing transport model at mach numbers between 0.6 and 1.4

    NASA Technical Reports Server (NTRS)

    Black, R. L.; Beamish, J. K.; Alexander, W. K.

    1975-01-01

    Models of three practical oblique-wing transport configurations were tested in the NASA Ames 11 foot wind tunnel. The three configurations used a common forward fuselage, wing, and support system but employed different aft fuselage sections simulating alternate propulsion system installations. These included an integrated propulsion system, pylon-mounted nacelles, and clean (no propulsion system) configuration. The tests were conducted over a Mach number range from 0.6 to 1.4 and at sweep angles from 0 to 60 degrees. The nominal unit Reynolds number was 1.83 million per meter and the angle of attack range was -3 to +6 degrees. The models were mounted in the tunnel by means of a lower blade support system. The interference effects of this lower blade and the flow inclination were determined by using an image blade system and testing the configuration in both the upright and inverted positions.

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

    SciTech Connect

    Zhai, Yanhua, E-mail: yanhuazhai@gmail.com, E-mail: jfan@nist.gov; Fan, Jingyun, E-mail: yanhuazhai@gmail.com, E-mail: jfan@nist.gov; Migdall, Alan [Joint Quantum Institute, National Institute of Standards and Technology and University of Maryland, 100 Bureau Drive, Mail Stop 8441, Gaithersburg, Maryland 20899 (United States); Becerra, Francisco E. [Center for Quantum Information and Control, MSC07-4220, University of New Mexico, Albuquerque, New Mexico 87131 (United States)

    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.

  8. 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. [Department of Physics and Astronomy, University of Iowa 203 Van Allen Hall, Iowa City, Iowa, 52245 (United States); Vincena, S. [Department of Physics and Astronomy, University of California Los Angeles 1000 Veteran Avenue, Suite 15-70, Los Angeles, California, 90095-1696 (United States)

    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.

  9. Using a qubit to measure photon number statistics of a driven, thermal oscillator

    Microsoft Academic Search

    Aashish Clerk; Dian Wahyu Utami

    2007-01-01

    We demonstrate theoretically how photon number statistics of a driven, damped oscillator at finite temperature can be extracted by measuring the dephasing spectrum of a two-level system dispersively coupled to the oscillator; previous results only dealt with the purely thermal or zero-temperature driven cases [1][2]. We also consider the fidelity of this scheme-- to what extent does the measurement reflect

  10. Measurement of high-field electron transport in silicon carbide

    Microsoft Academic Search

    Imran A. Khan; James A. Cooper

    2000-01-01

    We report recent measurements of the drift velocity of electrons parallel to the basal plane in 6H and 4H silicon carbide (SiC) as a function of applied electric field. The dependence of the low field mobility and saturated drift velocity on temperature are also reported. The saturated drift velocities at room temperature are approximately 1.9×107 cm\\/s in 6H-SiC and 2.2×107

  11. Experimental evidence of interhemispheric transport from airborne carbon monoxide measurements

    NASA Technical Reports Server (NTRS)

    Newell, R. E.; Gauntner, D. J.

    1979-01-01

    During the period 28-30 October 1977, a Pan American 747-SP aircraft flew around the world with an automated instrument package that included measurements of atmospheric CO made every 4 sec. The flight path extended from San Francisco, over the North Pole to London, south to Capetown, over the South Pole to Auckland, and back to San Francisco. The data collected show large changes with longitude, which are interpreted as direct evidence of interhemispheric mixing. Possible sources for CO are discussed.

  12. Tight Oracle Bounds for Low-rank Matrix Recovery from a Minimal Number of Random Measurements

    E-print Network

    Candes, Emmanuel J.

    Tight Oracle Bounds for Low-rank Matrix Recovery from a Minimal Number of Random Measurements targets: 1) the minimax risk, 2) an `oracle' error that would be available if the column space of the matrix were known, and 3) a more adaptive `oracle' error which would be available with the knowledge

  13. Mahler Measure and Hyperbolic Volumes Junior Number Theory Seminar University of Texas at Austin

    E-print Network

    Lalín, Matilde

    Mahler Measure and Hyperbolic Volumes Junior Number Theory Seminar ­ University of Texas at Austin over wxy is D y-w x-w = D y-w x-w ei . This function has several properties. It is real analytic in C ei + log |a| + log |b| + log |c| log max{|a|, |b|, |c|} not (9) Here stands for the statement

  14. Using cavitation to measure statistics of low-pressure events in large-Reynolds-number turbulence

    E-print Network

    La Porta, Arthur

    Using cavitation to measure statistics of low-pressure events in large-Reynolds-number turbulence A is studied using cavitation. The flow is seeded with microscopic gas bubbles and the hydrostatic pressure is reduced until large negative pressure fluctuations trigger cavitation. Cavitation is detected via light

  15. The number distribution of complex shear modulus of single cells measured by atomic force microscopy

    Microsoft Academic Search

    Shinichiro Hiratsuka; Yusuke Mizutani; Masahiro Tsuchiya; Koichi Kawahara; Hiroshi Tokumoto; Takaharu Okajima

    2009-01-01

    The viscoelastic properties of a large number of mouse fibroblast NIH3T3 cells (n?130) were investigated by combining atomic force microscopy (AFM) with a microarray technique. In the experiments, the cells were arranged and cultured in the wells of a microarray substrate, and a force modulation mode experiment was used to measure the complex shear modulus, G*, of individual cells in

  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. Instrument Development Procedures for Mathematics Measures. Technical Report Number 08-02

    ERIC Educational Resources Information Center

    Jung, Eunju; Liu, Kimy; Ketterlin-Geller, Leanne R.; Tindal, Gerald

    2008-01-01

    The purpose of this study was to develop general outcome measures (GOM) in mathematics so that teachers could focus their instruction on needed prerequisite skills. We describe in detail, the manner in which content-related evidence was established and then present a number of statistical analyses conducted to evaluate the technical adequacy of…

  18. Reynolds number measurements for turbulent Rayleigh-Bénard convection with 0 . 17 < Pr < 0 . 88

    NASA Astrophysics Data System (ADS)

    Hogg, James; Ahlers, Guenter

    2012-11-01

    We report Reynolds-number measurements from space-time cross-correlation functions of shadowgraph images taken of turbulent Rayleigh-Bénard convection in a cylindrical cell of height L = 9 . 5 mm and aspect ratio ? = 10 . 6 . The fluids were pure gases with Prandtl-numbers Pr ~ 0 . 7 and gas mixtures with 0 . 17 <= Pr < 0 . 7 . The Rayleigh-number range was 105 <= Ra <=108 . The elliptic approximation of He and Zhang was used to calculate the mean flow velocity U and the rms fluctuation velocity V. For this system U was close to zero, and the Reynolds number ReV based on V had Ra - and Pr -dependences consistent with the Grossmann-Lohse model. Work supported by NSF grant DMR11-58514.

  19. 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.

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

    SciTech Connect

    Yan, Qiurong, E-mail: yanqiurong@ncu.edu.cn [Department of Electronics Information Engineering, Nanchang University, Nanchang 330031 (China); State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119 (China); Zhao, Baosheng [State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119 (China); Liao, Qinghong; Zhou, Nanrun [Department of Electronics Information Engineering, Nanchang University, Nanchang 330031 (China)

    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.

  1. 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

  2. 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.

  3. 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.

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

    SciTech Connect

    Karnik, U. (Novacor Research and Technology Corp., Calgary, Alberta (Canada))

    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.

  5. Static and dynamic measurements of the Nusselt number in turbulent convection

    NASA Astrophysics Data System (ADS)

    Niemela, J. J.

    2013-07-01

    Measurements of the dimensionless heat transfer rate, or Nusselt number Nu, are typically made by static measurements of the heat flux and the average resulting temperature difference across a horizontal layer of fluid under steady state conditions. Here, we describe a dynamic method that uses the properties of a heat wave generated by sinusoidally modulating the boundary temperatures to calculate the Nusselt number from measured temperature fluctuations in the bulk. A comparison with static methods shows excellent agreement within 2% for Ra ? 109 for cells of aspect ratios 1 and 4, having different heights and for significant variations in frequency and amplitude of the modulation. This excellent agreement breaks down for well-developed turbulent convection at larger Ra ? 1013.

  6. Intervention measures, turning point, and reproduction number for dengue, Singapore, 2005.

    PubMed

    Hsieh, Ying-Hen; Ma, Stefan

    2009-01-01

    The 2005 dengue outbreak in Singapore cumulated in > 14,000 cases and 27 reported dengue deaths. We fit the single-phase Richards model to weekly dengue notification numbers to detect the turning point for the outbreak, which enables us to study the impact of intervention measures relating to the turning point. The results indicate that turning point had most likely occurred in late August or early September, before large-scale intervention measures were implemented. The "initial" reproduction number for the outbreak is estimated to be ~1.89-2.23 (95% confidence interval: 1.15-3.00). One of the lessons learned from the 2003 severe acute respiratory syndrome (SARS) outbreak is that multiple phases of outbreak were observed in some affected countries when efforts to intensify intervention or to sustain vigilance were compromised. Intensive and continuing efforts in the implementation of control measures are essential in reducing further dengue occurrences during any resurgence of dengue. PMID:19141842

  7. Spin transport and precession in graphene measured by nonlocal and three-terminal methods

    SciTech Connect

    Dankert, André, E-mail: andre.dankert@chalmers.se; Kamalakar, Mutta Venkata; Bergsten, Johan; Dash, Saroj P., E-mail: saroj.dash@chalmers.se [Department of Microtechnology and Nanoscience, Chalmers University of Technology, SE-41296 Göteborg (Sweden)

    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.

  8. 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.

  9. Measurements and Modeling of Ionosphere-Plasmasphere Transport

    NASA Astrophysics Data System (ADS)

    Sandel, B. R.; Denton, M. H.

    2005-12-01

    A fundamental aspect of the coupling between Earth's ionosphere and inner magnetosphere is the flow of ionospheric plasma that supplies material to the plasmasphere. Using global observations of the He+ column abundance made by the IMAGE Extreme Ultraviolet Imager, we investigate refilling of the plasmasphere after erosion events associated with geomagnetic storms. To minimize the confounding effects of phenomena other than refilling, we first focus on an usually quiet period of several days beginning on 27~June 2001. Just prior to this time, a moderate erosion event moved the plasmapause inward to L=3--4. During the next 3 days, the plasmasphere refilled so that the plasmaspause moved outward past geosynchronous orbit. For this and other similar study periods, we compare the He+ column abundances inferred from the EUV images with the predictions of the SUPIM model. The model solves the equations of continuity, momentum and energy balance that describe the physical and chemical processes occurring along closed field lines, and output from the model includes the He+ abundance. Comparing the model results to the azimuthally-averaged measurements shows generally good agreement, both in the rates of refilling as a function of radial distance and in the final shape of the radial profile of He+ column abundance. A more-detailed view, including analysis of azimuthal structure in the EUV images, suggests that the refilling rate is not always uniform in azimuth.

  10. Measurement of quasi-ballistic heat transport across nanoscale interfaces using ultrafast coherent soft x-ray beams

    Microsoft Academic Search

    M. Siemens; Q. Li; R. Yang; K. Nelson; E. Anderson; M. Murnane; H. Kapteyn

    2009-01-01

    Understanding heat transport on nanoscale dimensions is important for fundamental advances in nanoscience, as well as for practical applications such as thermal management in nano-electronics, thermoelectric devices, photovoltaics, nanomanufacturing, as well as nanoparticle thermal therapy. Here we report the first time-resolved measurements of heat transport across nanostructured interfaces. We observe the transition from a diffusive to a ballistic thermal transport

  11. Deformation of an elastic body in low Reynolds number transport: Relevance to biofilm deformation and streamer formation

    E-print Network

    Gupta, Nikhil; Mitra, Sushanta K; Kumar, Aloke

    2015-01-01

    In this paper, we obtain analytical results for shear stress distributions inside an elastic body placed in a low Reynolds number transport. The problem definition is inspired by a recent experimental study (Valiei et al., Lab Chip, 2012, 12, 5133-5137) that reports the flow-triggered deformation of bacterial biofilms, formed on cylindrical rigid microposts, into long filamentous structures known as streamers. In our analysis, we consider an elastic body of finite thickness (forming a rim) placed over a rigid cylinder, i.e., we mimic the biofilm structure in the experiment. We consider Oseen flow solution to describe the low Reynolds transport past this cylindrical elastic structure. The stress and strain distributions inside the elastic structure are found to be functions of position, Poisson ratio, initial thickness of the elastic rim and the ratio of the flow-driven shear stress to the shear modulus of the elastic body. More importantly, these analyses, which can be deemed as one of the first formal analys...

  12. The measurement of respiratory electron-transport-system activity in marine zooplankton

    Microsoft Academic Search

    T. G. Owens; F. D. King

    1975-01-01

    A modification of the tetrazolium reduction method (Packard, 1971) for measurement of respiratory electron transport system activity in marine zooplankton is described. A major modification is the addition of Triton X-100 to the reaction mixture to solubilize formazan produced, thus eliminating an organic extraction step and increasing the sensitivity and versatility of the method. The kinetic parameters of the assay

  13. Environmental and Transport Effects on Core Measurements of Water Saturation, Salinity, Wettability, and Hydrocarbon Composition

    E-print Network

    Torres-Verdín, Carlos

    SPE 166154 Environmental and Transport Effects on Core Measurements of Water Saturation, Salinity of Texas at Austin Copyright 2013, Society of Petroleum Engineers This paper was prepared for presentation and core surfacing operations can significantly alter the water saturation, salinity, hydrocarbon

  14. Photosystem I cyclic electron transport: Measurement of ferredoxin-plastoquinone reductase activity

    Microsoft Academic Search

    Robyn E. Cleland; Derek S. Bendall

    1992-01-01

    Absorbance changes of ferredoxin measured at 463 nm in isolated thylakoids were shown to arise from the activity of the enzyme ferredoxin-plastoquinone reductase (FQR) in cyclic electron transport. Under anaerobic conditions in the presence of DCMU and an appropriate concentration of reduced ferredoxin, a light-induced absorbance decrease due to further reduction of Fd was assigned to the oxidation of the

  15. Introduction The discrete case Measures The Euclidean case Gradient flows, optimal transport,

    E-print Network

    Savaré, Giuseppe

    ;Introduction The discrete case Measures The Euclidean case Gaspard Monge (1746-1818) 1781: "La th´eorie des d efficient" way. 42 3 The founding fathers of optimal transport minimize the total cost. Monge assumed by the distance. x d´eblais remblais T y Fig. 3.1. Monge's problem of d´eblais and remblais Nowadays

  16. Using Travel Time Reliability Measures to Improve Regional Transportation Planning and URS Corporation

    E-print Network

    Bertini, Robert L.

    Using Travel Time Reliability Measures to Improve Regional Transportation Planning and Operations revised from original submittal. #12;Lyman and Bertini 2 Abstract. Travel time estimation is of increasing. In fact, the reliability of travel time estimates on a given corridor may be more important for travelers

  17. In situ Magnetotransport Measurements in Ultrathin Bi Films: Evidence for Surface-Bulk Coherent Transport

    E-print Network

    Hasegawa, Shuji

    a single channel transport. For the films thicker than 20 BLs, the behavior changes drastically which can matter physics due to the emergence of gra- phene and topological insulators [1,2]. However properties of Bi [7­10]. However, these measurements were performed in air and it is questionable whether

  18. Transport Properties for Aqueous Sodium Sulfonate Surfactants 2. Intradiffusion Measurements: Influence of the Obstruction Effect

    E-print Network

    Annunziata, Onofrio

    Transport Properties for Aqueous Sodium Sulfonate Surfactants 2. Intradiffusion Measurements@chemna.dichi.unina.it Received July 24, 1998; accepted April 14, 1999 Intradiffusion coefficients of sodium alkylsulfonates [CH3 the computation of the Gouy­Chapman layer thickness from the experimental coefficients has been proposed

  19. Design, implementation, and performance measurement of a native-mode ATM transport layer (extended version)

    Microsoft Academic Search

    Ritesh Ahuja; Srinivasan Keshav; Huzur Saran

    1996-01-01

    We describe the design, implementation, and per- formance measurement of a transport layer targeted specifically for asynchronous transfer mode (ATM) networks. The layer has been built from scratch to minimize overhead in the critical path, provide per-virtual circuit quality of service (QoS) guarantees, and take advantage of ATM adaptation layer 5 functionality. It provides retiable and unreliable data delivery with

  20. 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...

  1. Transportable lidar for the measurement of ozone concentration and flux profiles in the lower troposphere

    Microsoft Academic Search

    Yanzeng Zhao; James N. Howell; R. Michael Hardesty

    1992-01-01

    In many areas of the United States, as well as in other industrial areas (such as Europe), elevated and potentially harmful levels of ozone are being measured during summer. Most of this ozone is photochemically produced. The relatively long lifetime of ozone allows industrially produced ozone to be transported on a hemispheric scale. Since the trends of tropospheric ozone are

  2. Examining injection properties of boreal forest fires using surface and satellite measurements of CO transport

    Microsoft Academic Search

    Edward J. Hyer; Dale J. Allen; Eric S. Kasischke

    2007-01-01

    Boreal forest fires are highly variable in space and time and also have variable vertical injection properties. We compared a University of Maryland Chemistry and Transport Model (UMD-CTM) simulation of boreal forest fire CO in the summer of 2000 to surface observations from the NOAA Cooperative Air Sampling Network and satellite observations of CO from the Measurement of Pollutants in

  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. Comparison of microfluidic digital PCR and conventional quantitative PCR for measuring copy number variation

    PubMed Central

    Whale, Alexandra S.; Huggett, Jim F.; Cowen, Simon; Speirs, Valerie; Shaw, Jacqui; Ellison, Stephen; Foy, Carole A.; Scott, Daniel J.

    2012-01-01

    One of the benefits of Digital PCR (dPCR) is the potential for unparalleled precision enabling smaller fold change measurements. An example of an assessment that could benefit from such improved precision is the measurement of tumour-associated copy number variation (CNV) in the cell free DNA (cfDNA) fraction of patient blood plasma. To investigate the potential precision of dPCR and compare it with the established technique of quantitative PCR (qPCR), we used breast cancer cell lines to investigate HER2 gene amplification and modelled a range of different CNVs. We showed that, with equal experimental replication, dPCR could measure a smaller CNV than qPCR. As dPCR precision is directly dependent upon both the number of replicate measurements and the template concentration, we also developed a method to assist the design of dPCR experiments for measuring CNV. Using an existing model (based on Poisson and binomial distributions) to derive an expression for the variance inherent in dPCR, we produced a power calculation to define the experimental size required to reliably detect a given fold change at a given template concentration. This work will facilitate any future translation of dPCR to key diagnostic applications, such as cancer diagnostics and analysis of cfDNA. PMID:22373922

  5. Measurement of thermal transport using time-resolved thermal wave microscopy

    SciTech Connect

    Marat Khafizov; David H. Hurley

    2011-10-01

    A theoretical and experimental analysis of time-resolved thermal wave microscopy (TRTWM) technique used for thermal wave imaging is presented. TRTWM combines the elements of both frequency and time domain laser based thermoreflectance approaches widely used for thermal wave imaging and measurement of thermal transport. An analytical thermal wave model used for analysis is described and compared to experimental results. Implementation of TRTWM to measure thermal conductivities of materials of interest is demonstrated.

  6. Troposphere-Stratosphere transport in the tropics from CALIPSO lidar aerosols measurements

    Microsoft Academic Search

    J.-P. Vernier; J.-P. Pommereau; A. Garnier; J. Pelon

    2009-01-01

    Troposphere Stratosphere transport in the tropics from CALIPSO lidar aerosols measurements J.P. Vernier, J.P. Pommereau, A. Garnier and J. Pelon CNRS-LATMOS Verrières le Buisson, 91371 France The evolution of the aerosols in the tropical tropopause region is investigated from the CALIOP lidar measurements onboard the CALIPSO satellite. After applying a correction for calibration and appropriate cloud mask, a consistent picture

  7. A directional quantifying Doppler system for measurement of transport velocity of blood.

    PubMed

    De Jong, D A; Megens, P H; De Vlieger, M; Thön, H; Holland, W P

    1975-05-01

    A transcutaneous Doppler device has been developed that measures primarily the directional transport velocity of blood, averaged over the vessel diameter, irrespective of its flow in adjacent vessels. Directional information is obtained by high or low-pass filtering of frequency converted versions of the received Doppler signals, applying low-cost, sharp filters in a superheterodyne system. Upper and lower channel signals are quantified separately to average directional velocity. Linear results from in vitro measurements are obtained. PMID:1138476

  8. Measurement of Automotive Nonvolatile Particle Number Emissions within the European Legislative Framework: A Review

    Microsoft Academic Search

    Barouch Giechaskiel; Athanasios Mamakos; Jon Andersson; Panagiota Dilara; Giorgio Martini; Wolfgang Schindler; Alexander Bergmann

    2012-01-01

    In 2011, the European Commission introduced a limit for nonvolatile particle number (PN) emissions >23 nm from light-duty (LD) vehicles and the stated intent is to implement similar legislation for on-road heavy-duty (HD) engines at the next legislative stage. This paper reviews the recent literature regarding the operation-dependent emission of PN from LD vehicles and HD engines, and the measurement

  9. Measurement of Automotive Non-Volatile Particle Number Emissions within the European Legislative Framework: A Review

    Microsoft Academic Search

    BAROUCH GIECHASKIEL; ATHANASIOS MAMAKOS; JON ANDERSSON; PANAGIOTA DILARA; GIORGIO MARTINI; WOLFGANG SCHINDLER; ALEXANDER BERGMANN

    2012-01-01

    In 2011 the European Commission introduced a limit for non-volatile particle number (PN) emissions >23 nm from light-duty vehicles and the stated intent is to implement similar legislation for on-road heavy-duty engines at the next legislative stage. This paper reviews the recent literature regarding the operation-dependent emission of PN from light-duty vehicles and heavy-duty engines, and the measurement procedure used

  10. 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.

  11. Anion transport heterogeneity detected by flow cytometric measurement of NBD-taurine efflux kinetics.

    PubMed

    Muirhead, K A; Steinfeld, R C; Severski, M C; Knauf, P A

    1984-05-01

    NBD-taurine [N-(7-nitrobenzofuran-4-yl) taurine], a fluorescent substrate for the human erythrocyte anion exchange system, has been used to test the feasibility of making flow cytometric measurements of anion transport in K562 erythroleukemic cells. Cells were preloaded by incubation with 20 microM-2mM NBD-taurine, then diluted 10-30-fold, and efflux was monitored by measuring fluorescence intensity (FL) as a function of time using excitation at 488 nm. The observed rate of decrease in fluorescence was sensitive to temperature and also to phloretin, a compound known to inhibit anion transport and other carrier-mediated transport processes. The coefficient of variation (CV) of the fluorescence distribution increased markedly over the efflux period, suggesting heterogeneity of the K562 population with respect to the rate constant for NBD-taurine efflux. This heterogeneity was also reflected in the upward curvature of a first order plot of log (FLt - FL infinity) versus time. Half-times calculated from initial linear portions of the first-order plots were found to decrease as the loading concentration of NBD-taurine was decreased, as predicted for a saturable transport system. NBD-taurine is not an ideal anion transport substrate for flow cytometric studies. It appears to bind to high-affinity sites within the cells with consequent fluorescence quenching, complicating interpretation of kinetic curves at low concentrations.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:6587962

  12. 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

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

    NASA Astrophysics Data System (ADS)

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

    2015-06-01

    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.

  14. 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

  15. 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. [National Institute of Standards and Technology, Boulder, Colorado 80305 (United States)

    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.

  16. Integrating field measurements and flume experiments for analysing fluvial bedload transport and channel morphodynamics in steep mountain streams

    NASA Astrophysics Data System (ADS)

    Beylich, Achim A.; Laute, Katja; Liermann, Susan

    2013-04-01

    Fluvial bedload transport, temporal storage of material and channel morphodynamics have high importance for sedimentary budgets of steep catchments and steep mountain streams. In addition, headwater catchments and steep mountain streams can be relevant sediment sources for lowland river systems. Since 2004 extended and interdisciplinary field investigations on fluvial bedload transport and channel morphodynamics have been conducted in a number of selected stream segments in supply-limited fluvial systems in the inner Nordfjord (Erdalen and Bødalen drainage basins) in western Norway. A range of different methods and techniques have been used. Field studies in the Erdalen drainage basin (79.5 km2) and the Bødalen drainage basin (60.1 km2) have included (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 channel segments. Additional field studies with impact sensors were carried out in selected transport-limited fluvial systems in the Coast Mountains of British Columbia (Canada) in 2010 and 2011. The field studies have been combined with flume experiments for calibration of field measurements, especially for the calibration of the measurements that have been carried out with impact sensors in Norway and Canada. As a key achievement, the entire range of different bedload component grain sizes can be covered by the applied combination of techniques. The flux of bedload material can be quantified and is related to the spatio-temporal variability of sediment supply / availability within the drainage basins and to temporal sediment storage within the channel systems.

  17. 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).

  18. 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.

  19. High-Reynolds-number flat-plate turbulent boundary layer measurements

    NASA Astrophysics Data System (ADS)

    Winkel, Eric S.; Cutbirth, James M.; Perlin, Marc; Ceccio, Steven L.; Dowling, David R.

    2006-11-01

    A set of experiments was conducted in the U.S. Navy's Large Cavitation Channel (LCC) into the characteristics of a liquid turbulent boundary layer at nearly zero-pressure-gradient. The hydraulically smooth, k^+ < 0.2, flat-plate test model measured 12.9 m in length and 3.05 m in span and was approximately centered in the LCC test section. Data was gathered at flow speeds up to 20 m/s to achieve downstream-distance-based Reynolds numbers up to 220 million. Static pressure, skin-friction, and laser-Doppler velocimetry (LDV) measurements are presented. Static pressure measurements along the plate surface show a mild favorable pressure gradient, less than 2.5% flow acceleration over the model. Skin-friction was measured at six stream-wise positions with 15-cm-diameter, flush-mounted drag-balances. Flow profiles of the mean and second-order turbulence statistics of stream-wise and wall-normal velocity components were measured using two-component LDV. When normalized with the measured skin-friction, mean velocity profiles agree with the accepted law-of-the-wall constants and the total near-wall shear stress approaches unity.

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

    NASA Astrophysics Data System (ADS)

    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 ~?-2/5 if 0.05???20?m-2 [Phys. Rev. Lett.PRLTAO0031-900710.1103/PhysRevLett.74.330 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, Schüller, and Frey [Phys. Rev. EPLEEE81063-651X10.1103/PhysRevE.81.021904 81, 021904 (2010)].

  1. Accurate Measurement of Mitochondrial DNA Deletion Level and Copy Number Differences in Human Skeletal Muscle

    PubMed Central

    Blakely, Emma L.; Haller, Ronald G.; Taylor, Robert W.; Turnbull, Doug M.; Tuppen, Helen A. L.

    2014-01-01

    Accurate and reliable quantification of the abundance of mitochondrial DNA (mtDNA) molecules, both wild-type and those harbouring pathogenic mutations, is important not only for understanding the progression of mtDNA disease but also for evaluating novel therapeutic approaches. A clear understanding of the sensitivity of mtDNA measurement assays under different experimental conditions is therefore critical, however it is routinely lacking for most published mtDNA quantification assays. Here, we comprehensively assess the variability of two quantitative Taqman real-time PCR assays, a widely-applied MT-ND1/MT-ND4 multiplex mtDNA deletion assay and a recently developed MT-ND1/B2M singleplex mtDNA copy number assay, across a range of DNA concentrations and mtDNA deletion/copy number levels. Uniquely, we provide a specific guide detailing necessary numbers of sample and real-time PCR plate replicates for accurately and consistently determining a given difference in mtDNA deletion levels and copy number in homogenate skeletal muscle DNA. PMID:25474153

  2. Measurements Concerning Generation of Rhomboid Rills in Flume Experiments: Froude Number and Sand-Topographic Feature

    NASA Astrophysics Data System (ADS)

    Endo, Noritaka; Takashi, Murakami; Izumi, Norihiro

    2013-03-01

    Rhomboid rills, small sand topographies often observed in the swash zone of beach slopes, are apparently similar but different from rhomboid ripples that have been relatively well researched. Rhomboid rills are composed of thin grooves, while rhomboid ripples are of the tilelike geometry. A recent study showed a difference in the dependence of rhombus angle on the slope gradient between rhomboid rills and rhomboid ripples. In this study, we measured Froude numbers during the generation of rhomboid rills and found that the trend of rhombus angles versus Froude numbers was similar to that in the case of rhomboid ripples. We discuss similarities and dissimilarities between rhomboid rills and rhomboid ripples, showing an open problem.

  3. 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.

  4. Transportable Lidar for the Measurement of Ozone Concentration and Flux Profiles in the Lower Troposphere

    NASA Technical Reports Server (NTRS)

    Zhao, Yanzeng; Howell, James N.; Hardesty, R. Michael

    1992-01-01

    In many areas of the United States, as well as in other industrial areas (such as Europe), elevated and potentially harmful levels of ozone are being measured during summer. Most of this ozone is photochemically produced. The relatively long lifetime of ozone allows industrially produced ozone to be transported on a hemispheric scale. Since the trends of tropospheric ozone are very likely dependent on the source strengths and distributions of the pollutants and the chemical/ transport process involved, a predictive understanding of tropospheric ozone climatology requires a focus on the chemical and transport processes that link regional emissions to hemispheric ozone trends and distributions. Of critical importance to these studies is a satisfactory data base of tropospheric ozone distribution from which global and regional tropospheric ozone climatology can be derived, and the processes controlling tropospheric ozone can be better understood. A transportable lidar for measuring ozone concentration and flux profiles in the lower troposphere is needed. One such system is being developed at the National Oceanic and Atmospheric Administration/Earth Resources Laboratory (NOAA/ERL) Wave Propagation Laboratory (WPL).

  5. Measurements of Peroxy Radicals in Air Masses Undergoing Long Range Transport During ITOP

    NASA Astrophysics Data System (ADS)

    Parker, A. E.; Monks, P. S.; Jacob, M. J.; Green, T. J.; Penkett, S. A.; Methven, J.

    2005-12-01

    The sum of organic peroxy radicals (?RiO2) and HO2 was measured with a dual-channel PEroxy Radical Chemical Amplifier (PERCA) deployed on an aircraft platform (the NERC/UKMO BAe 146-300) during the Intercontinental Transport of Ozone and Precursors (ITOP) campaign held in July/August 2004 based out of Faial, Azores. Peroxy radicals are key intermediates and chain carriers in the gas phase oxidation of volatile organic compounds, and owing to their short lifetime give an indication of in-situ photochemical ozone production. Enhanced levels of peroxy radicals were observed within polluted air masses undergoing long-range transport during ITOP and this work focuses on the importance of in-situ photochemical production and long-range transport in determining the composition of the troposphere remote from the source region. The measurements of peroxy radicals and analyses of their role within photochemically active air masses undergoing transport shall be presented. In particular, an assessment of the photochemical activity of a range of air masses undergoing LRT with different source signatures will be presented.

  6. Truly Random Number Generation Based on Measurement of Phase Noise of Laser

    E-print Network

    Hong Guo; Wenzhuo Tang; Yu Liu; Wei Wei

    2010-01-20

    We present a simple approach to realize truly random number generation based on measurement of the phase noise of a single mode vertical cavity surface emitting laser (VCSEL). The true randomness of the quantum phase noise originates from the spontaneous emission of photons and the random bit generation rate is ultimately limited only by the laser linewidth. With the final bit generation rate of 20 Mbit/s, the physically guaranteed truly random bit sequence passes the three standard random tests. Moreover, for the first time, a {\\it continuously} generated random bit sequence up to 14 Gbit is verified by two additional criteria for its true randomness.

  7. Truly Random Number Generation Based on Measurement of Phase Noise of Laser

    E-print Network

    Guo, Hong; Liu, Yu

    2009-01-01

    A simple approach to realize true random number generation based on measurement of the phase noise of a single mode vertical cavity surface emitting laser is presented. The true randomness of the phase noise originates from the spontaneous emission of photon and the random bit generation rate is only limited by the laser linewidth. The physically guaranteed true randomness of the final random bits passes the three standard random tests and the final random bit generation rate is 20 Mbit/s with an extremely minor bias ($10^{-6}$).

  8. 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.

  9. Measurements of high number densities of ice crystals in the tops of tropical cumulonimbus

    NASA Astrophysics Data System (ADS)

    Knollenberg, R. G.; Kelly, K.; Wilson, J. C.

    1993-05-01

    Imaging and light scattering instruments were used during the January/February 1987 STEP Tropical Experiment at Darwin, Australia, to measure ice crystal size distributions in the tops of tropical cumulonimbus anvils associated with tropical cyclones and related cloud systems. Two light scattering instruments covered particles from 0.1-?m to 78-?m diameter. Particles larger than 50-?m diameter were imaged with a two-dimensional Grey optical array imaging probe. The measurements were made at altitudes ranging from 13 to 18 km at temperatures ranging from -60° to -90°C. Additional measurements made in continental cumulonimbus anvils in the western United States offer a comparative data set. The tropical anvil penetrations revealed surprisingly high concentrations of ice crystals. Number densities were typically greater than 10 cm-3 with up to 100 cm-3 if one includes all particles larger than 0.1 ?m and can approach condensation nuclei in total concentration. In order to explain the high number densities, ice crystal nucleation at altitude is proposed with the freezing of fairly concentrated solution droplets in equilibrium at low relative humidities. Any dilute liquid phase is hypothesized to be transitory with a vanishingly short lifetime and limited to cloud levels nearer -40°C. Homogeneous nucleation of ice involving H2SO4 nuclei is attractive in explaining the high number densities of small ice crystals observed near cloud top at temperatures below -60°C. The tropical size distributions were converted to mass using a spherical equivalent size, while the continental anvil data were treated as crystalline plates. Comparisons of the ice water contents integrated from the mass distributions with total water contents measured with NOAA Lyman-alpha instruments require bulk densities equivalent to solid ice for best agreement. Correlation between the two data sets for a number of flight passes was quite good and was further improved by subtraction of water vapor density values ranging between ice and water saturation. Ice water contents up to 0.07 g m-3 were observed in the tropical anvils with over 0.1 g m-3 in continental anvils. The size distributions in tropical anvils generally reveal mass modes at sizes of 20-40 ?m. With rare exceptions, particles larger than 100 ?m were not observed near the cloud tops. In continental cumulonimbus anvils, much larger plate crystals approaching 1 mm in size account for the majority of the ice water. Most of the ice crystal mass lofted to anvil altitudes falls to lower levels prior to evaporating. The anvils can experience strong radiational heating as well as cooling depending upon lower cloud cover, particle size distribution, and time of day.

  10. Investigation of device imperfection influence on measurement results in beamsplitter-based quantum random number generation schemes

    NASA Astrophysics Data System (ADS)

    Ivanova, A. E.; Chivilikhin, S. A.; Egorov, V. I.; Gleim, A. V.

    2014-10-01

    Quantum random number generation allows acquiring true random numbers which can be used in applications that require a high degree of randomness. This paper assesses the influence of non-ideal scheme parameters on measurement results in two quantum random number generation schemes: based on laser radiation splitting, and using vacuum fluctuations.

  11. 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

    ...2011-07-01 2011-07-01 false Test Concentration Ranges, Number of Measurements Required...C-1 to Subpart C of Part 53—Test Concentration Ranges, Number of Measurements Required...Discrepancy Specifications Pollutant Concentration range, parts per million (ppm)...

  12. The large volume radiometric calorimeter system: A transportable device to measure scrap category plutonium

    SciTech Connect

    Duff, M.F.; Wetzel, J.R.; Breakall, K.L.; Lemming, J.F.

    1987-01-01

    An innovative design concept has been used to design a large volume calorimeter system. The new design permits two measuring cells to fit in a compact, nonevaporative environmental bath. The system is mounted on a cart for transportability. Samples in the power range of 0.50 to 12.0 W can be measured. The calorimeters will receive samples as large as 22.0 cm in diameter by 43.2 cm high, and smaller samples can be measured without lengthening measurement time or increasing measurement error by using specially designed sleeve adapters. This paper describes the design considerations, construction, theory, applications, and performance of the large volume calorimeter system. 2 refs., 5 figs., 1 tab.

  13. Acceleration and support post deformation measurements during surface and tunnel transport of a LHC Short Straight Section

    E-print Network

    Capatina, O; CERN. Geneva. TS Department

    2004-01-01

    This technical note is a complement to the technical note [1]. The former technical note dealt with the experimental modal analysis and the road transport with transport restraints and special suspension. The present note describes the measured accelerations and support post deformations during road transport at reduced speed without end restraints or special suspension. This note also reports the accelerations and support post deformations during handling and tunnel transport with the dedicated tunnel vehicle. The measured accelerations are compared with the specified acceleration limits.

  14. Boundary layer measurements and their implications for sediment transport on the eastern Norwegian Sea continental slope

    Microsoft Academic Search

    Erika E. McPhee; Arthur R. M. Nowell; Richard W. Sternberg

    1998-01-01

    Benthic currents, temperature, salinity, and suspended sediment concentration were measured in 1993–1994 on the Bear Island Fan, at water depths of approximately 1700m, near the wreckage of the Russian nuclear submarine “Komsomolets”. A maximum current speed of 51cm\\/s and a mean speed of approximately 10cm\\/s was recorded. There was a marked seasonal pattern in flow strength, and the net transport

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

    Microsoft Academic Search

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

    1994-01-01

    The evolution of the tritium density profile is inferred from 14.1 MeV t(d,n)alpha and 2.5 MeV d(d,n)He-3 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

  16. Radio wave propagation measurements in tunnel entrance environment for intelligent transportation systems applications

    Microsoft Academic Search

    A. V. B. da Silva; M. Nakagawa

    2001-01-01

    Underground environments are of great interest to intelligent transportation system (ITS) applications, since they occur frequently in both urban and rural situations, and have peculiar propagation characteristics. This investigation includes two of the major fields in ITS applications: road-to-vehicle, and vehicle-to-vehicle communications. Besides that, the propagation measurements presented also focus on the transition effects when moving between the regions outside

  17. Measurements of Peroxy Radicals in Air Masses Undergoing Long Range Transport During ITOP

    Microsoft Academic Search

    A. E. Parker; P. S. Monks; M. J. Jacob; T. J. Green; S. A. Penkett; J. Methven

    2005-01-01

    The sum of organic peroxy radicals (sigmaRiO2) and HO2 was measured with a dual-channel PEroxy Radical Chemical Amplifier (PERCA) deployed on an aircraft platform (the NERC\\/UKMO BAe 146-300) during the Intercontinental Transport of Ozone and Precursors (ITOP) campaign held in July\\/August 2004 based out of Faial, Azores. Peroxy radicals are key intermediates and chain carriers in the gas phase oxidation

  18. Measurement of water transport from saturated pumice aggregates to hardening cement paste

    Microsoft Academic Search

    Pietro Lura; Dale P. Bentz; David A. Lange; Konstantin Kovler; Arnon Bentur; Klaas van Breugel

    2006-01-01

    In internal water curing of High Performance Concrete, it is fundamental to know how and when the water contained in the internal\\u000a curing agent is released into the hydrating cement paste. In this study, X-ray absorption measurements showed that considerable\\u000a transport of water from saturated pumice stone to hydrating cement paste with water\\/cement ratio 0.3 took place in the first

  19. 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.

  20. Dynamics of dispersive photon-number QND measurements in a micromaser

    SciTech Connect

    Kozlovskii, A. V. [Russian Academy of Sciences, Lebedev Physical Institute (Russian Federation)], E-mail: kozlovsk@sci.lebedev.ru

    2007-04-15

    A numerical analysis of dispersive quantum nondemolition measurement of the photon number of a microwave cavity field is presented. Simulations show that a key property of the dispersive atom-field interaction used in Ramsey interferometry is the extremely high sensitivity of the dynamics of atomic and field states to basic parameters of the system. When a monokinetic atomic beam is sent through a microwave cavity, a qualitative change in the field state can be caused by an uncontrollably small deviation of parameters (such as atom path length through the cavity, atom velocity, cavity mode frequency detuning, or atom-field coupling constants). The resulting cavity field can be either in a Fock state or in a super-Poissonian state (characterized by a large photon-number variance). When the atoms have a random velocity spread, the field is squeezed to a Fock state for arbitrary values of the system's parameters. However, this makes detection of Ramsey fringes impossible, because the probability of detecting an atom in the upper or lower electronic state becomes a random quantity almost uniformly distributed over the interval between zero and unity, irrespective of the cavity photon number.

  1. 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

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

    DOEpatents

    McGrail, Bernard P. (Pasco, WA); Martin, Paul F. (Richland, WA); Lindenmeier, Clark W. (Richland, WA)

    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.

  3. Analysis of aircraft and satellite measurements from the intercontinental chemical transport experiment (INTEX-B) to quantify long-range transport of East Asian Sulfur to Canada

    Microsoft Academic Search

    A. van Donkelaar; R. V. Martin; W. R. Leaitch; A. M. MacDonald; T. W. Walker; D. G. Streets; Q. Zang; E. J. Dunlea; J. L. Jimenez; J. E. Dibb; G. Huley; R. Weber; M. O. Andreae

    2008-01-01

    We interpret a suite of satellite, aircraft, and ground-based measurements over the North Pacific Ocean and western North America during April-May 2006 as part of the Intercontinental Chemical Transport Experiment Phase B (INTEX-B) campaign to understand the implications of long-range transport of East Asian emissions to North America. The Canadian component of INTEX-B included 33 vertical profiles from a Cessna

  4. Detection and Correction of Blinking Bias in Image Correlation Transport Measurements of Quantum Dot Tagged Macromolecules

    PubMed Central

    Durisic, Nela; Bachir, Alexia I.; Kolin, David L.; Hebert, Benedict; Lagerholm, B. Christoffer; Grutter, Peter; Wiseman, Paul W.

    2007-01-01

    Semiconductor nanocrystals or quantum dots (QDs) are becoming widely used as fluorescent labels for biological applications. Here we demonstrate that fluorescence fluctuation analysis of their diffusional mobility using temporal image correlation spectroscopy is highly susceptible to systematic errors caused by fluorescence blinking of the nanoparticles. Temporal correlation analysis of fluorescence microscopy image time series of streptavidin-functionalized (CdSe)ZnS QDs freely diffusing in two dimensions shows that the correlation functions are fit well to a commonly used diffusion decay model, but the transport coefficients can have significant systematic errors in the measurements due to blinking. Image correlation measurements of the diffusing QD samples measured at different laser excitation powers and analysis of computer simulated image time series verified that the effect we observe is caused by fluorescence intermittency. We show that reciprocal space image correlation analysis can be used for mobility measurements in the presence of blinking emission because it separates the contributions of fluctuations due to photophysics from those due to transport. We also demonstrate application of the image correlation methods for measurement of the diffusion coefficient of glycosyl phosphatidylinositol-anchored proteins tagged with QDs as imaged on living fibroblasts. PMID:17526586

  5. Prevalence of transportation safety measures portrayed in primetime US television programs and commercials

    PubMed Central

    McGwin, G; Modjarrad, K; Reiland, A; Tanner, S; Rue, L W

    2006-01-01

    Objective To determine the prevalence of transportation related safety behaviors, such as seatbelt and helmet use, in primetime US television programs and commercials. Design Cross sectional study. Setting Top rated television programs and associated commercials from four major US television networks were reviewed for the prevalence of transportation safety related behaviors during a one month period in 2005. Programs were categorized according to the time and network of airing, program type, program rating, and—for commercials—type of product being advertised Subjects Occupants of automobiles, motorcycles, or bicycles in 507 instances in which a transportation scene was aired. Results Seatbelt use was depicted in 62% and 86% of individuals in television program and commercial automobile scenes, respectively. The prevalence of motorcycle helmet use was 47% in television programs and 100% in commercials. Bicycle helmets were used in 9% of television programs and 84% of commercials. The frequency of seatbelt use in programs and commercials varied by television rating and genre but did not differ by network, time of airing, or age of character portrayed. Conclusions The prevalence of safety related behaviors aired on major US networks during primetime slots is higher than previous reports but still much lower than national averages. Commercials, in contrast, portray transportation safety measures with a frequency that exceeds that of US television programs or most national surveys. PMID:17170190

  6. 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.

  7. A transverse emittance and acceptance measurement system in a low-energy beam transport line.

    PubMed

    Kashiwagi, H; Miyawaki, N; Kurashima, S; Okumura, S

    2014-02-01

    A transverse beam emittance and acceptance measurement system has been developed to visualize the relationship between the injected beam emittance and the acceptance of a cyclotron. The system is composed of a steering magnet, two pairs of slits to limit the horizontal and vertical phase-space, a beam intensity detector just behind the slits for the emittance measurement, and a beam intensity detector in the cyclotron for the acceptance measurement. The emittance is obtained by scanning the slits and measuring the beam intensity distribution. The acceptance is obtained by measuring the distribution of relative beam transmission by injecting small emittance beams at various positions in a transverse phase-space using the slits. In the acceptance measurement, the beam from an ion source is deflected to the defined region by the slits using the steering magnet so that measurable acceptance area covers a region outside the injection beam emittance. Measurement tests were carried out under the condition of accelerating a beam of (16)O(6+) from 50.2 keV to 160 MeV. The emittance of the injected beam and the acceptance for accelerating and transporting the beam to the entrance of the extraction deflector were successfully measured. The relationship between the emittance and acceptance is visualized by displaying the results in the same phase-plane. PMID:24593469

  8. A transverse emittance and acceptance measurement system in a low-energy beam transport line

    SciTech Connect

    Kashiwagi, H., E-mail: kashiwagi.hirotsugu@jaea.go.jp; Miyawaki, N.; Kurashima, S.; Okumura, S. [Department of Advanced Radiation Technology, Japan Atomic Energy Agency, 1233 Watanuki, Takasaki, Gunma 370-1292 (Japan)] [Department of Advanced Radiation Technology, Japan Atomic Energy Agency, 1233 Watanuki, Takasaki, Gunma 370-1292 (Japan)

    2014-02-15

    A transverse beam emittance and acceptance measurement system has been developed to visualize the relationship between the injected beam emittance and the acceptance of a cyclotron. The system is composed of a steering magnet, two pairs of slits to limit the horizontal and vertical phase-space, a beam intensity detector just behind the slits for the emittance measurement, and a beam intensity detector in the cyclotron for the acceptance measurement. The emittance is obtained by scanning the slits and measuring the beam intensity distribution. The acceptance is obtained by measuring the distribution of relative beam transmission by injecting small emittance beams at various positions in a transverse phase-space using the slits. In the acceptance measurement, the beam from an ion source is deflected to the defined region by the slits using the steering magnet so that measurable acceptance area covers a region outside the injection beam emittance. Measurement tests were carried out under the condition of accelerating a beam of {sup 16}O{sup 6+} from 50.2 keV to 160 MeV. The emittance of the injected beam and the acceptance for accelerating and transporting the beam to the entrance of the extraction deflector were successfully measured. The relationship between the emittance and acceptance is visualized by displaying the results in the same phase-plane.

  9. 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.

  10. 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.

  11. Measurements of Inertial Limit Alfven Wave Dispersion for Finite Perpendicular Wave Number C. A. Kletzing,1,* D. J. Thuecks,1

    E-print Network

    California at Los Angles, University of

    Measurements of Inertial Limit Alfve´n Wave Dispersion for Finite Perpendicular Wave Number C. A verified the correct E=B ratio for these waves [6,7]. Measurements of Alfve´n waves in the laboratory were temperature was measured with a swept Langmuir probe and found to be 1.9 eV in the region where the waves were

  12. Transportation and lairage environment effects on prevalence, numbers, and diversity of Escherichia coli O157:H7 on hides and carcasses of beef cattle at processing.

    PubMed

    Arthur, Terrance M; Bosilevac, Joseph M; Brichta-Harhay, Dayna M; Guerini, Michael N; Kalchayanand, Norasak; Shackelford, Steven D; Wheeler, Tommy L; Koohmaraie, Mohammad

    2007-02-01

    Hide has been established as the main source of carcass contamination during cattle processing; therefore, it is crucial to minimize the amount of Escherichia coli O157:H7 on cattle hides before slaughter. Several potential sources of E. coli O157: H7 are encountered during transportation and in the lairage environment at beef-processing facilities that could increase the prevalence and numbers of E. coli O157:H7 on the hides of cattle. On three separate occasions, samples were obtained from cattle at the feedlot and again after cattle were stunned and exsanguinated at the processing plant (286 total animals). The prevalence of E. coli O157:H7 on hides increased from 50.3 to 94.4% between the time cattle were loaded onto tractor-trailers at the feedlot and the time hides were removed in the processing plant. Before transport, nine animals had E. coli O157:H7 in high numbers (> 0.4 CFU/cm2) on their hides. When sampled at the slaughter facility, the number of animals with high hide numbers had increased to 70. Overall, only 29% of the E. coli O157:H7 isolates collected postharvest (221 of 764) matched pulsed-field gel electrophoresis types collected before transport. The results of this study indicate that transport to and lairage at processing plants can lead to increases in the prevalence and degree of E. coli O157:H7 contamination on hides and the number of E. coli O157:H7 pulsed-field gel electrophoresis types associated with the animals. More study is needed to confirm the mechanism by which additional E. coli O157:H7 strains contaminate cattle hides during transport and lairage and to design interventions to prevent this contamination. PMID:17340859

  13. 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.

  14. Transport and Measurements of High-Current Electron Beams from X pinches

    SciTech Connect

    Agafonov, Alexey V.; Mingaleev, Albert R.; Romanova, Vera M. [P.N. Lebedev Physical Institute of Russian Academy of Sciences, Moscow 119991 (Russian Federation); Tarakanov, Vladimir P. [Institute for High-Energy Densities of Russian Academy of Sciences, Moscow 125412 (Russian Federation); Shelkovenko, Tatiana A.; Pikuz, Sergey A.; Blesener, Isaac C.; Kusse, Bruce R.; Hammer, David A. [Cornell University, Ithaca, NY 14853 (United States)

    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.

  15. Measurements of Electron Transport in Foils Irradiated with a Picosecond Time Scale Laser Pulse

    SciTech Connect

    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. [Directorate Science and Technology, AWE Aldermaston, Reading RG7 4PR (United Kingdom); Shepherd, R.; Dunn, J.; Chen, H.; Schneider, M.; Brown, G.; Beiersdorfer, P.; Emig, J. [Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, California 94550 (United States)

    2011-05-06

    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{sup 16}-10{sup 19} W/cm{sup 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.

  16. Truly random number generation based on measurement of phase noise of a laser

    NASA Astrophysics Data System (ADS)

    Guo, Hong; Tang, Wenzhuo; Liu, Yu; Wei, Wei

    2010-05-01

    We present a simple approach to realize truly random number generator based on measuring the phase noise of a single-mode vertical cavity surface emitting laser. The true randomness of the quantum phase noise originates from the spontaneous emission of photons and the random bit generation rate is ultimately limited only by the laser linewidth. With the final bit generation rate of 20 Mbit/s, the truly random bit sequence guaranteed by the uncertainty principle of quantum mechanics passes the three standard randomness tests (ENT, Diehard, and NIST Statistical Test Suites). Moreover, a continuously generated random bit sequence, with length up to 14 Gbit, is verified by two additional criteria for its true randomness.

  17. Truly random number generation based on measurement of phase noise of a laser.

    PubMed

    Guo, Hong; Tang, Wenzhuo; Liu, Yu; Wei, Wei

    2010-05-01

    We present a simple approach to realize truly random number generator based on measuring the phase noise of a single-mode vertical cavity surface emitting laser. The true randomness of the quantum phase noise originates from the spontaneous emission of photons and the random bit generation rate is ultimately limited only by the laser linewidth. With the final bit generation rate of 20 Mbit/s, the truly random bit sequence guaranteed by the uncertainty principle of quantum mechanics passes the three standard randomness tests (ENT, Diehard, and NIST Statistical Test Suites). Moreover, a continuously generated random bit sequence, with length up to 14 Gbit, is verified by two additional criteria for its true randomness. PMID:20866215

  18. Measurements of the vortex wakes of a subsonic and supersonic transport model in the 40 by 80 foot wind tunnel

    NASA Technical Reports Server (NTRS)

    Rossow, V. J.; Corsiglia, V. R.; Phillippe, J. J.

    1974-01-01

    The rolling moment induced on aircraft models in the wake of a model of a subsonic transport and of a supersonic transport was measured as a function of angle of attack for several configurations. The tests are described and an analysis of the data is given in this memorandum.

  19. Fluorescence assays for measuring fatty acid binding and transport through membranes.

    PubMed

    Brunaldi, Kellen; Simard, Jeffrey R; Kamp, Frits; Rewal, Charu; Asawakarn, Tanong; O'Shea, Paul; Hamilton, James A

    2007-01-01

    The authors' laboratory has applied a series of different fluorescence assays for monitoring the binding and transport of fatty acids (FA) in model and biological membranes. The authors recently expanded their fluorescent assays for monitoring the adsorption of FA to membranes to a total of three probes that measure different aspects of FA binding: (1) an acrylodan-labeled FA-binding protein, which measures the partitioning of FA between membranes and the aqueous buffer; (2) the naturally occurring fluorescent cis-parinaric acid, which specifically measures the insertion of the FA acyl chain into the hydrophobic core of the phospholipid bilayer, and (3) a fluorescein-labeled phospholipid (N-fluorescein-5-thiocarbomoyl-1,2,dihexadecanoyl-sn-glycero-3-phosphoethanolamine), which specifically measures the arrival of the FA carboxyl at the outer leaflet of the membrane. None of these probes allow the transmembrane movement of FA to the inner leaflet to be measured. FA translocation (flip-flop) is typically measured directly, using a pH-sensitive fluorophore such as 8-hydroxypyrene-1.3.6-trisulfonic acid or 2',7'-bis-(2-carboxyethyl)-5-(and-6)- carboxyfluorescein. These probes detect the release of protons from unionized FA that have diffused through the membrane to the inner leaflet. Because adsorption of FA to the outer leaflet must occur before flip-flop, these probes measure the effects of the combined steps of adsorption and translocation. In this chapter, detailed methods are provided on how to monitor the transport of FA through protein-free model membranes, and some of the fluorescent artifacts that may arise with the use of these probes are addressed. Also, experiments designed to investigate such artifacts, and improve the reliability and interpretation of the data are described. PMID:17951738

  20. 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.

  1. 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 |?xt|˜|?x0|exp[?t(x0)?(t)], where ? (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 ? (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 ?(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.

  2. 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 |?xt|?|?x0|exp[?t(x0)?(t)], where ?(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 ?(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 ????(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

  3. A New Method for Measuring Weak Lensing Magnification With Weighted Number Counts

    E-print Network

    Gillis, Bryan

    2015-01-01

    We present a new 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. This method has equivalent statistical power to the optimally-weighted correlation function method previously employed to measure magnification, but has the potential to be used for purposes such as mass mapping, and is also significantly computationally faster. We present a proof-of-principle test of this method on data from the CFHTLenS, 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-fit 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 ga...

  4. Leroy Apker Award Talk: Transport measurements of a model cuprate superconductor

    NASA Astrophysics Data System (ADS)

    Veit, Michael

    2015-03-01

    High-temperature superconductivity in the cuprates has been the subject of intense research since its discovery in 1986 by J. G. Bednorz and K. A. Müller. The fundamental challenge posed by these materials is that they exhibit strong electronic correlations, giving rise to anomalous properties, such as the observation that the resistivity in optimally hole-doped samples is linear in temperature from the superconducting transition temperature up to very high temperatures. The scope of this work was to explore the phase diagram through transport measurements of a model compound. Specifically, the resistivity, magneto-resistance, Hall effect and thermoelectric power were measured for single-crystal samples of HgBa2CuO4+? (Hg1201). The outcome of these measurements is highly surprising. Despite the complexity of the phase diagram, conventional Fermi-liquid metallic behavior is observed in the pseudogap regime below optimal doping.

  5. Phase-controlled, heterodyne laser-induced transient grating measurements of thermal transport properties in opaque material

    E-print Network

    Johnson, Jeremy A.

    The methodology for a heterodyned laser-induced transient thermal grating technique for non-contact, non-destructive measurements of thermal transport in opaque material is presented. Phase-controlled heterodyne detection ...

  6. 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...

  7. A critical analysis of sketch-planning tools for evaluating the emissions benefits of transportation control measures

    E-print Network

    Crawford, Jason Aaron

    1993-01-01

    -planning tools are now available. The two premier sketch-planning tools used for evaluating transportation control measures are the Systems Applications International (SAI) method and the San Diego Association of Governments (SANDAG) method. Both methods were...

  8. 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.

  9. A critical analysis of sketch-planning tools for evaluating the emissions benefits of transportation control measures 

    E-print Network

    Crawford, Jason Aaron

    1993-01-01

    A CRITICAL ANALYSIS OF SKETCH-PLANNING TOOLS FOR EVALUATING THE EMISSIONS BENEFITS OF TRANSPORTATION CONTROL MEASURES A Thesis by JASON AARON CRAWFORD Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment... of the requirements for the degree of MASTER OF SCIENCE December 1993 Major Subject: Civil Engineering A CRITICAL ANALYSIS OF SKETCH-PLANNING TOOLS FOR EVALUATING THE EMISSIONS BENEFITS OF TRANSPORTATION CONTROL MEASURES A Thesis by JASON AARON CRAWFORD...

  10. Transport measurements across Caco-2 monolayers of different organic and inorganic selenium

    Microsoft Academic Search

    Gerard Leblondel; Yves Mauras; Annie Cailleux; Pierre Allain

    2001-01-01

    The transport and uptake of the most common Se compounds, selenate (SeO\\u000a 4\\u000a 2?\\u000a ), selenite (SeO\\u000a 3\\u000a 2?\\u000a ), selenomethionine, and selenocystine, were investigated using confluent monolayers of Caco-2 cells, a human carcinoma cell\\u000a line. Comparative measurements were performed in the absorptive (apical to basolateral side) and exsorptive (basolateral to\\u000a apical side) directions. Apparent permeability coefficients (P\\u000a app), calculated

  11. Measurement of temperature, density, and particle transport with localized dopants in wire-array Z pinches.

    PubMed

    Jones, B; Deeney, C; McKenney, J L; Ampleford, D J; Coverdale, C A; Lepell, P D; Shelton, K P; Safronova, A S; Kantsyrev, V L; Osborne, G; Sotnikov, V I; Ivanov, V V; Fedin, D; Nalajala, V; Yilmaz, F; Shrestha, I

    2008-03-14

    Axially localized NaF dopants are coated onto Al cylindrical wire arrays in order to act as spectroscopic tracers in the stagnated z-pinch plasma. Non-local-thermodynamic-equilibrium kinetic models fit to Na K-shell lines provide an independent measurement of the density and temperature that is consistent with spectroscopic analysis of K-shell emissions from Al and an alloyed Mg dopant. Axial transport of the Na dopant is observed, enabling quantitative study of instabilities in dense z-pinch plasmas. PMID:18352197

  12. 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

  13. Gold nanoparticles grown inside carbon nanotubes: synthesis and electrical transport measurements.

    PubMed

    Segura, Rodrigo A; Contreras, Claudia; Henriquez, Ricardo; Häberle, Patricio; Acuña, José Javier S; Adrian, Alvaro; Alvarez, Pedro; Hevia, Samuel A

    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. 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.

  15. 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.

  16. 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 constrain

  17. Incorporation of Fine-Grained Sediment Erodibility Measurements into Sediment Transport Modeling, Capitol Lake, Washington

    USGS Publications Warehouse

    Stevens, Andrew W.; Gelfenbaum, Guy; Elias, Edwin; Jones, Craig

    2008-01-01

    Capitol Lake was created in 1951 with the construction of a concrete dam and control gate that prevented salt-water intrusion into the newly formed lake and regulated flow of the Deschutes River into southern Puget Sound. Physical processes associated with the former tidally dominated estuary were altered, and the dam structure itself likely caused an increase in retention of sediment flowing into the lake from the Deschutes River. Several efforts to manage sediment accumulation in the lake, including dredging and the construction of sediment traps upriver, failed to stop the lake from filling with sediment. The Deschutes Estuary Feasibility Study (DEFS) was carried out to evaluate the possibility of removing the dam and restoring estuarine processes as an alternative ongoing lake management. An important component of DEFS was the creation of a hydrodynamic and sediment transport model of the restored Deschutes Estuary. Results from model simulations indicated that estuarine processes would be restored under each of four restoration alternatives, and that over time, the restored estuary would have morphological features similar to the predam estuary. The model also predicted that after dam-removal, a large portion of the sediment eroded from the lake bottom would be deposited near the Port of Olympia and a marina located in lower Budd Inlet seaward of the present dam. The volume of sediment transported downstream was a critical piece of information that managers needed to estimate the total cost of the proposed restoration project. However, the ability of the model to predict the magnitude of sediment transport in general and, in particular, the volume of sediment deposition in the port and marina was limited by a lack of information on the erodibility of fine-grained sediments in Capitol Lake. Cores at several sites throughout Capitol Lake were collected between October 31 and November 1, 2007. The erodibility of sediments in the cores was later determined in the lab with Sedflume, an apparatus for measuring sediment erosion-parameters. In this report, we present results of the characterization of fine-grained sediment erodibility within Capitol Lake. The erodibility data were incorporated into the previously developed hydrodynamic and sediment transport model. Model simulations using the measured erodibility parameters were conducted to provide more robust estimates of the overall magnitudes and spatial patterns of sediment transport resulting from restoration of the Deschutes Estuary.

  18. Transporter

    Microsoft Academic Search

    Keisuke Mitsuoka; Sosuke Miyoshi; Yukio Kato; Yoshihiro Murakami; Rie Utsumi; Yoshiyuki Kubo; Akihiro Noda; Yukio Nakamura; Shintaro Nishimura; Akira Tsuji

    in the tumor-bearing mice, and in mice with inflammatory tissue, wereassessedbyimagingwithapositron planarimagingsystem (PPIS). Tissue distributions of tracer radioactivity were also measured. The expression levels of PEPT1 and PEPT2 (PEPTs) proteins in tumor xenografts and inflammatory tissue were examined by immunohistochemical analysis. The messenger RNA expression levels of PEPTs in 58 available cancer cell lines were quantified by means of real-time

  19. 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.

  20. 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.

  1. 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

  2. Optical analogue for phase-sensitive measurements in quantum-transport experiments

    NASA Astrophysics Data System (ADS)

    Citrin, D. S.

    1999-08-01

    The Aharonov-Bohm effect has recently been employed to measure the quantum-mechanical phase of an electron propagating ballistically through a quantum dot (QD) contained in one arm of the interferometer [Schuster et al., Nature (London) 385, 417 (1997)]. Jauho and Wingreen [Phys. Rev. B 58, 9619 (1998)] have analyzed this geometry under conditions where the QD is modulated harmonically in time as a way to distinguish unambiguously between coherent [e.g., photon-assisted transport] and incoherent processes [e.g., sequential resonant tunneling]. We show that an optical analogue of this experiment exists, namely, the propagation of light through a quantum well in the vicinity of an excitonic resonance subjected to a THz electric field. By carrying out an interferometric experiment, the phase of a transmitted (or reflected) optical beam at a sideband frequency-analogous to the electron's phase-can be measured. These phase shifts can be understood in terms of specific multi-THz-photon processes. The optical experiment affords fundamental insight not ordinarily accessible in transport experiments.

  3. Parallel measurement of conductive and convective thermal transport of micro/nanowires based on Raman mapping

    NASA Astrophysics Data System (ADS)

    Li, Man; Li, Changzheng; Wang, Jianmei; Xiao, Xiangheng; Yue, Yanan

    2015-06-01

    Heat conduction and convection are coupled effects in thermal transport of low-dimensional materials especially at micro/nanoscale. However, the parallel measurement is a challenge due to the limitation of characterization pathways. In this work, we report a method to study conductive and convective thermal transport of micro/nanowires simultaneously by using steady-state Joule-heating and Raman mapping. To examine this method, the carbon nanotubes (CNTs) fiber (36 ?m in diameter) is characterized and its temperature dependence of thermal properties including thermal conductivity and convection coefficient in ambient air is studied. Preliminary results show that thermal conductivity of the CNTs fiber increases from 26 W/m K to 34 W/m K and convection coefficient decreases from 1143 W/m2 K to 1039 W/m2 K with temperature ranging from 312 to 444 K. The convective heat dissipation to the air could be as high as 60% of the total Joule heating power. Uncertainty analysis is performed to reveal that fitting errors can be further reduced by increasing sampling points along the fiber. This method features a fast/convenient way for parallel measurement of both heat conduction and convection of micro/nanowires which is beneficial to comprehensively understanding the coupled effect of micro/nanoscale heat conduction and convection.

  4. Troposphere-Stratosphere transport in the tropics from CALIPSO lidar aerosols measurements

    NASA Astrophysics Data System (ADS)

    Vernier, J.-P.; Pommereau, J.-P.; Garnier, A.; Pelon, J.

    2009-04-01

    Troposphere Stratosphere transport in the tropics from CALIPSO lidar aerosols measurements J.P. Vernier, J.P. Pommereau, A. Garnier and J. Pelon CNRS-LATMOS Verrières le Buisson, 91371 France The evolution of the aerosols in the tropical tropopause region is investigated from the CALIOP lidar measurements onboard the CALIPSO satellite. After applying a correction for calibration and appropriate cloud mask, a consistent picture of the aerosols since the beginning of the mission in June 2006 until present is provided. Most remarkable features are the presence of several volcanic plumes at various levels further lifted by the Brewer-Dobson circulation, and the injection of clean washed-out tropospheric air up to 19-20 km particularly intense during the maximum land convective season in February-March resulting in the cleansing of the Tropical Tropopause Layer (TTL). Most important implications relevant to Troposphere to Stratosphere transport is the suggestion of the existence of a maximum static stability layer at about 19.5 km (450 K, 60 hPa) suggesting a decoupling of the circulation between Holton's "lowermost stratosphere" and "overworld", and the importance at global scale of fast convective overshooting of tropospheric air across the tropopause up to the altitude of the above static layer.

  5. Indoor and outdoor measurements of particle number concentration in near-highway homes.

    PubMed

    Fuller, Christina H; Brugge, Doug; Williams, Paige L; Mittleman, Murray A; Lane, Kevin; Durant, John L; Spengler, John D

    2013-01-01

    Exposure to high levels of traffic-generated particles may pose risks to human health; however, limited measurement has been conducted at homes near highways. The purpose of this study was to characterize differences between indoor and outdoor particle number concentration (PNC) in homes near to and distant from a highway and to identify factors that may affect infiltration. We monitored indoor and outdoor PNC (6-3000 nm) for 1-3 weeks at 18 homes located <1500 m from Interstate-93 (I-93) in Somerville, MA (USA). Median hourly indoor and outdoor PNC pooled over all homes were 5.2 × 10(3) and 5.9 × 10(3) particles/cm(3), respectively; the median ratio of indoor-to-outdoor PNC was 0.95 (5(th)/95th percentile: 0.42/1.75). Homes <100 m from I-93 (n=4) had higher indoor and outdoor PNC compared with homes >1000 m away (n=3). In regression models, a 10% increase in outdoor PNC was associated with an approximately equal (10.8%) increase in indoor PNC. Wind speed and direction, temperature, time of day and weekday were also associated with indoor PNC. Average mean indoor PNC was lower for homes with air conditioners compared with homes without air conditioning. These results may have significance for estimating indoor, personal exposures to traffic-related air pollution. PMID:23321863

  6. AC-transport measurements of ion beam irradiated GaMnAs semiconductors

    NASA Astrophysics Data System (ADS)

    Sinnecker, Elis; Santánna, Marcelo; Rappoport, Tatiana; Mendes, Joaquim; Pires, Mauricio; Penello, Germano; Souza, Deivid; Mello, Sergio; Furdyna, Jacek; Liu, Xinyu

    2013-03-01

    GaMnAs is a diluted magnetic semiconductors in which lattice atoms have been partially substituted by magnetic atoms, thus inserting a local magnetic moment into the lattice. Recently it was shown that ion beam irradiation can be an effective tool to modify the magnetic and electronic properties of Ga1-xMnxAs thin films. We observed that an increase of the structural disorder by irradiation leads to a systematic decrease on the saturation magnetization. Here, we provide further information on the electronic properties of irradiated samples. Measurements of ac-resistivity, magnetoresistance and Hall resistance were performed from 5K to 300K applying a DC magnetic field up to 7T. The results show an interesting frequency dependence of the ac-transport of measured irradiated samples. For the sake of comparison, data on irradiated non-magnetic semiconductor, grown on the same conditions as Ga1-xMnxAs thin films, are provided. GaMnAs is a diluted magnetic semiconductors in which lattice atoms have been partially substituted by magnetic atoms, thus inserting a local magnetic moment into the lattice. Recently it was shown that ion beam irradiation can be an effective tool to modify the magnetic and electronic properties of Ga1-xMnxAs thin films. We observed that an increase of the structural disorder by irradiation leads to a systematic decrease on the saturation magnetization. Here, we provide further information on the electronic properties of irradiated samples. Measurements of ac-resistivity, magnetoresistance and Hall resistance were performed from 5K to 300K applying a DC magnetic field up to 7T. The results show an interesting frequency dependence of the ac-transport of measured irradiated samples. For the sake of comparison, data on irradiated non-magnetic semiconductor, grown on the same conditions as Ga1-xMnxAs thin films, are provided. 00879

  7. 1120 | VOL.9 NO.11 | NOVEMBER2012 | nAture methods measuring complete gene expression profiles for a large number

    E-print Network

    Cai, Long

    selecting a probe subset and learning a predictive model of genome-wide expression from measurements to a large-scale study of immune system variation. Gene expression profiling is commonly used to study the number of measurements grows combinatorially. The financial cost of genome-wide assays in experiments

  8. Time-Domain Thermoreflectance Measurements of Thermal Transport in Amorphous SiC Thin Films

    NASA Astrophysics Data System (ADS)

    Daly, Brian; Hondongwa, Donald; King, Sean

    2010-03-01

    We present ultrafast optical pump-probe measurements of thermal transport in a series of amorphous SiC samples. The samples were grown on Si wafers by plasma enhanced chemical vapor deposition utilizing various combinations of methylsilanes and H2 and He diluent gases. The sample films were well characterized and found to have densities (1.3 -- 2.3 g cm-3) and dielectric constants (4.0 -- 7.2) that spanned a wide range of values. Prior to their measurement, the samples were coated with 40-70 nm of polycrystalline Al. The pump-probe measurements were performed at room temperature using a modelocked Ti:sapphire laser that produced sub-picosecond pulses of a few nJ. The pulses heat the Al coating, causing a transient reflectivity change. As the Al film cools into the SiC film, the reflectivity change can be measured, giving a measure of the thermal effusivity of the SiC film. We then extract values for the thermal conductivity of the SiC films and find that it varies from less than half of the thermal conductivity of amorphous SiO2 for the lower density materials to somewhat larger than amorphous SiO2 for the highest density films.

  9. Eddy-correlation measurements of the resistance to vertical transport of ozone

    SciTech Connect

    Eastman, J.A.

    1983-01-01

    The major objective was to measure the resistance to ozone uptake over a variety of surfaces and under a variety of conditions. These resistance data along with new data on reaction-rate coefficients and the concentration of trace species can be incorporated into increasingly sophisticated models to provide a better understanding of the tropospheric ozone budget. Measurements made over a grass field showed a gradual decrease in the total resistance over an eight-week period in the spring. The data collected under overcast skies and before the grass had begun to turn green, was indicative of ozone destruction by nontranspiring surface material. The average resistance for the eight-week period was 2.3 s/cm. Eddy correlation measurements made over a mature maize crop showed a strong diurnal trend with minimum resistance occurring at midday. The average total resistance, 2.4 s/cm, was nearly the same as that measured over grass; however, the flux was about twice as large as that measured over grass since ozone concentrations were two times higher. Data collected over soybeans showed that the effective bulk-surface resistance was highly correlated to the canopy resistance to water-vapor transport, indicating the important role stomata play in controlling ozone uptake.

  10. Eddy correlation measurements of the resistance to vertical transport of ozone

    SciTech Connect

    Eastman, J.A.

    1983-01-01

    The major objective of this research project was to measure the resistance to ozone uptake over a variety of surfaces and under a variety of conditions. These resistance data along with new data on reaction rate coefficients and the concentration of trace species can be incorporated into increasingly sophisticated models to provide a better understanding of the tropospheric ozone budget. The ozone flux was determined by computing the covariance between the vertical wind speed and the ozone concentration using both analog and digital methods. The vertical wind speed was measured with a vertical propeller anemometer. The ozone concentration was measured with a chemiluminescent detector in which ozone in the ambient air was reacted with an excess of nitric oxide NO. Measurements made over a grass field showed a gradual decrease in the total resistance over an eight-week period in the spring. The average resistance for the eight-week period was 2.3 s/cm. Eddy correlation measurements made over a mature maize crop showed a strong diurnal trend with minimum resistance occurring at midday. The average total resistance was 2.4 s/cm. Data collected over soybeans showed that the effective bulk surface resistance was highly correlated to the canopy resistance to water vapor transport, indicating the important role stomata play in controlling ozone uptake.

  11. A Validation of Eye Movements as a Measure of Elementary School Children's Developing Number Sense

    ERIC Educational Resources Information Center

    Schneider, Michael; Heine, Angela; Thaler, Verena; Torbeyns, Joke; De Smedt, Bert; Verschaffel, Lieven; Jacobs, Arthur M.; Stern, Elsbeth

    2008-01-01

    The number line estimation task captures central aspects of children's developing number sense, that is, their intuitions for numbers and their interrelations. Previous research used children's answer patterns and verbal reports as evidence of how they solve this task. In the present study we investigated to what extent eye movements recorded…

  12. 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.

  13. Rounding of pumice clasts during transport: field measurements and laboratory studies

    NASA Astrophysics Data System (ADS)

    Manga, Michael; Patel, Ameeta; Dufek, Josef

    2010-05-01

    The volcanic clasts in many pyroclastic density currents are notably more round than in corresponding air fall deposits. This rounding has long been interpreted as evidence for comminution and abrasion during transport. Such comminution can be a secondary source of fine ash that in turn can influence the runount distance, deposit sorting, and the volume of ash introduced into the upper atmosphere. Information about ash production during transport should be preserved in the roundness of clasts.?? We performed experimental measurements to determine an empirical relationship between particle roundness (measured in two-dimensions by comparing the ratio of each particle's area and perimeter squared with the equivalent ratio for a sphere) and mass loss caused by particle-particle interactions. We consider, as examples, pumice from four volcanoes: Medicine Lake, California; Lassen, California; Taupo, New Zealand; Mount St Helens, Washington. We find that average sample roundness reaches a maximum value once particles lose between 15 and 60% of their mass. The most texturally homogeneous clasts (Taupo) become the most round. We compare our experimental measurements with the roundness of clasts in one of the May 18, 1980 pyroclastic density current units at Mount St Helens, deposited 4-8 km from the vent. The roundness measurements of these clasts are close to the experimentally determined maximum values, suggesting that a significant amount of ash may have been produced in-situ during transport. For a much smaller deposit from the 1915 Lassen eruption, clast roundness is closer to the value for air-fall pumice and suggests that only a few volume percent of large clasts were comminuted. In neither field deposit do we see a significant change in roundness with increasing distance from the vent. We suggest that this trend is recorded because much of the rounding and ash production occur in proximal regions where the density currents are the most energetic. As a result, all clasts that are deposited have experienced similar amounts of comminution in the proximal region, and similar amounts of abrasion as they settle through the dense, near-bed region prior to final deposition.

  14. Quantitative measurements and modeling of cargo-motor interactions during fast transport in the living axon.

    PubMed

    Seamster, Pamela E; Loewenberg, Michael; Pascal, Jennifer; Chauviere, Arnaud; Gonzales, Aaron; Cristini, Vittorio; Bearer, Elaine L

    2012-10-01

    The kinesins have long been known to drive microtubule-based transport of sub-cellular components, yet the mechanisms of their attachment to cargo remain a mystery. Several different cargo-receptors have been proposed based on their in vitro binding affinities to kinesin-1. Only two of these-phosphatidyl inositol, a negatively charged lipid, and the carboxyl terminus of the amyloid precursor protein (APP-C), a trans-membrane protein-have been reported to mediate motility in living systems. A major question is how these many different cargo, receptors and motors interact to produce the complex choreography of vesicular transport within living cells. Here we describe an experimental assay that identifies cargo-motor receptors by their ability to recruit active motors and drive transport of exogenous cargo towards the synapse in living axons. Cargo is engineered by derivatizing the surface of polystyrene fluorescent nanospheres (100 nm diameter) with charged residues or with synthetic peptides derived from candidate motor receptor proteins, all designed to display a terminal COOH group. After injection into the squid giant axon, particle movements are imaged by laser-scanning confocal time-lapse microscopy. In this report we compare the motility of negatively charged beads with APP-C beads in the presence of glycine-conjugated non-motile beads using new strategies to measure bead movements. The ensuing quantitative analysis of time-lapse digital sequences reveals detailed information about bead movements: instantaneous and maximum velocities, run lengths, pause frequencies and pause durations. These measurements provide parameters for a mathematical model that predicts the spatiotemporal evolution of distribution of the two different types of bead cargo in the axon. The results reveal that negatively charged beads differ from APP-C beads in velocity and dispersion, and predict that at long time points APP-C will achieve greater progress towards the presynaptic terminal. The significance of this data and accompanying model pertains to the role transport plays in neuronal function, connectivity, and survival, and has implications in the pathogenesis of neurological disorders, such as Alzheimer's, Huntington and Parkinson's diseases. PMID:23011729

  15. Quantitative measurements and modeling of cargo–motor interactions during fast transport in the living axon

    PubMed Central

    Seamster, Pamela E; Loewenberg, Michael; Pascal, Jennifer; Chauviere, Arnaud; Gonzales, Aaron; Cristini, Vittorio; Bearer, Elaine L

    2013-01-01

    The kinesins have long been known to drive microtubule-based transport of sub-cellular components, yet the mechanisms of their attachment to cargo remain a mystery. Several different cargo-receptors have been proposed based on their in vitro binding affinities to kinesin-1. Only two of these—phosphatidyl inositol, a negatively charged lipid, and the carboxyl terminus of the amyloid precursor protein (APP-C), a trans-membrane protein—have been reported to mediate motility in living systems. A major question is how these many different cargo, receptors and motors interact to produce the complex choreography of vesicular transport within living cells. Here we describe an experimental assay that identifies cargo–motor receptors by their ability to recruit active motors and drive transport of exogenous cargo towards the synapse in living axons. Cargo is engineered by derivatizing the surface of polystyrene fluorescent nanospheres (100 nm diameter) with charged residues or with synthetic peptides derived from candidate motor receptor proteins, all designed to display a terminal COOH group. After injection into the squid giant axon, particle movements are imaged by laser-scanning confocal time-lapse microscopy. In this report we compare the motility of negatively charged beads with APP-C beads in the presence of glycine-conjugated non-motile beads using new strategies to measure bead movements. The ensuing quantitative analysis of time-lapse digital sequences reveals detailed information about bead movements: instantaneous and maximum velocities, run lengths, pause frequencies and pause durations. These measurements provide parameters for a mathematical model that predicts the spatiotemporal evolution of distribution of the two different types of bead cargo in the axon. The results reveal that negatively charged beads differ from APP-C beads in velocity and dispersion, and predict that at long time points APP-C will achieve greater progress towards the presynaptic terminal. The significance of this data and accompanying model pertains to the role transport plays in neuronal function, connectivity, and survival, and has implications in the pathogenesis of neurological disorders, such as Alzheimer’s, Huntington and Parkinson’s diseases. PMID:23011729

  16. A proposed methodology for measuring public transport accessibility to employment sites in the Auckland CBD

    Microsoft Academic Search

    Mairi Joyce; Roger Dunn

    2009-01-01

    There is currently a global focus to increase the use of alternative modes of transport, particularly the use of Public Transport (PT) with the aim of minimising the economic and environmental costs of traffic congestion. Part of this change is to improve accessibility. If the PT modal share is to be increased, the transport authorities, transport planners and other professionals

  17. Laboratory Measurements of Fluid Transport Properties on Tight Gas Sandstones and Applications

    NASA Astrophysics Data System (ADS)

    Albrecht, Daniel; Reitenbach, Viktor

    2014-05-01

    Deep gas reservoirs are of great interest for the E&P industry. Large areas of such reservoirs have permeabilities below 1 mD. The reservoir rocks in these areas show a strong stress sensitivity of the fluid transport properties and a considerable productivity decline due to changing stress conditions during the production process. For correct modeling and simulation of Tight Gas reservoirs it is important to know the behavior of the fluid transport properties under the changing stress condition the reservoir experiences. In several measurement series the effects of changing overburden and pore pressure on Rotliegend sandstone samples from north German Tight Gas reservoirs have been quantified and used to set up correlation functions. With the correlation functions from the own measurements and additional data and correlations from literature a Rock Data Catalog has been developed as tool to help reservoir engineers with modeling and simulation of such reservoirs. The Rock Data Catalog consists of the Rock Database and the Correlation Module. The Rock Database contains general and petrophysical rock data. The Correlation Module uses this data to generate secondary data of e.g. in-situ capillary and hydraulic rock properties with appropriate correlation functions. Viability of the economic gas production from Tight Gas Reservoirs strongly depends on reservoir quality. Therefore identification of high quality reservoir parts or so called Sweet Spots for placing production wells and planning hydraulic fracturing stimulation, is one of key issues of the tight gas reservoir characterization and evaluation. The data and correlation functions collected in the Rock Data Catalog could also be used to identify Sweet Spots in Tight Gas reservoirs. Several rock parameters and properties, which affect the fluid flow in a reservoir (like lithology, clay content, water saturation, permeability, pore size distribution) can be identified and used to set up a Sweet Spot Index as a measure for the reservoir quality.

  18. Fluorescence measurements of anion transport by the GABA receptor in reconstituted membrane preparations

    SciTech Connect

    Dunn, S.M.J.; Shelman, R.A.; Agey, M.W. (Univ. of Iowa, Iowa City (USA))

    1989-03-21

    A fluorescence assay for measuring the functional properties of the GABA{sub A} receptor in reconstituted membrane vesicles is described. This assay is based on a method previously described to measure monovalent cation transport mediated by the nicotinic acetylcholine receptor in membranes from Torpedo electric organ. The GABA{sub A} receptor has been solubilized from bovine brain membranes and reconstituted into phospholipid vesicles. Influx of chloride or iodide into the vesicles has been measured in stopped-flow experiments by monitoring the fluorescence quench of an anion-sensitive fluorophore trapped within the vesicles. Muscimol, a GABA{sub A} receptor agonist, stimulated a rapid uptake of either chloride or iodide. Stimulation of chloride influx was dependent on the concentration of muscimol, and the midpoint of the dose-response curve occurred at approximately 0.3 {mu}M. Agonist-stimulated uptake was enhanced by diazepam and blocked by desensitization and by the antagonists bicuculline and picrotoxin. These receptor-mediated effects are shown to be qualitatively similar to measurements of {sup 36}Cl{sup {minus}} and {sup 125}I{sup {minus}} efflux using synaptoneurosomes prepared from rat cerebral cortex. The advantages of the fluorescence method in terms of its improved time resolution, sensitivity, and suitability for quantitating GABA{sub A} receptor function are discussed.

  19. Measuring Relevant Properties of Cohesive Sediment Aggregates ("Flocks") for Sediment Transport Modeling

    NASA Astrophysics Data System (ADS)

    Reed, A. H.; Zhang, G.; Tan, X.; Yin, H.; Furukawa, Y.

    2012-12-01

    Improvements to nearshore sediment transport models require increased fidelity and new data on the strength, density, structure and size of cohesive sediment aggregates or "flocs". To facilitate this, we developed new methods to evaluate flocculated sediments and the results that were generated facilitate improved numerical simulations of suspended and bedload sediment transport. Typically, flocs originate as aggregated clumps of clays and organic matter (e.g., biopolymers, humic acids) that chemically bond when they enter saline water, such that the floc particle grows in size until it is often orders of magnitude larger than the constituent particles. This important factor yields settling velocities for flocs that are orders of magnitude faster than that of the primary particles. Our recent work has compared the relationship of biopolymer-clay and clay-clay flocs in laboratory experiments that were conducted on synthetic (i.e., produced in the lab) and natural flocs (i.e., gathered from coastal estuaries). The size, shape and density of flocs directly impact transport properties such as hydrodynamic drag, hindered settling velocity and density, which are further altered by floc compressive and shear strength. Due to an inability to measure these transport and strength properties in situ on individual flocs, settling velocity of individual flocs has often been related to the fractal dimensionality, which is an indication of floc porosity, density and strength. Therefore, this work has correlated settling velocity with fractal dimensionality for both types of flocs in initial studies. Then in order to address the influence of flow velocity and fluid shear stress on floc shape and size, both floc types were entrained in a flow-through particle size analyzer to establish correlations between turbulent flow velocity and floc size modality. The compressive strength of these flocs was addressed directly by subjecting them to high-resolution (50 nN sensitivity) compression tests that provides a determination of the elastic modulus and yield shear strength. These data are requisite components of a sediment transport model that uses the discrete element method (DEM) to determine how particles respond to particle collisions within the water column. To address the influence consolidation of flocs that were deposited on the seafloor, a micro/nano-cone penetrometer was developed. This test uses a mm-sized cone that is coupled to a high-resolution load cell so that the strength of the top few mm of the newly formed seabed can be characterized in terms of bearing capacity and undrained shear strength. This data will be used to drive numerical simulations of cohesive bedload entrainment, transport and resuspension. Ultimately, these assessments will provide realistic and useful data to facilitate and improve various modeling efforts, which simulate and predict suspended sediment and bedload transport in estuarine and nearshore coastal environments where cohesive sediments abound.

  20. Testing the ae \\Lambda scaling of thermal transport models: predicted and measured temperatures in the Tokamak Fusion Test

    E-print Network

    Testing the ae \\Lambda scaling of thermal transport models: predicted and measured temperatures scaling experiments. The DIII­D [J. L. Luxon and L. G. Davis, Fusion Technol. 8, 441 (1985)] L­mode ae the measurement uncertainties. All the theoretical models predict a more favorable ae \\Lambda dependence

  1. [Gene insertion and deletion polymorphism in the serotonin transporter gene and personality traits measured by MMPI].

    PubMed

    Golimbet, V E; Alfimova, M V; Shcherbatykh, T V; Rogaev, E I

    2003-04-01

    Polymorphisms of the serotonin transporter gene are known to be associated with some personality traits measured by means of various psychological inventories. In the present work we attempted to find an association between genetic variants of serotonin transporter (loci VNTR-17 and 5-HTTLPR) and psychological traits scored by the MMPI inventory in 125 mentally healthy donors. No statistically significant differences in personality traits were found between carriers of different VNTR-17 genotypes. At locus 5-HTTLPR, significant between-genotype differences were revealed on the Schizophrenia scale (F = 3.49; P = 0.034) and on the validity scale F (F = 3.24; P = 0.042). The ss genotype carriers had the lowest scores on these scales. The score on the Psychopathic Deviate scale was significantly lower in the carriers of the ss genotype than in the combined group of the carriers of genotypes ll and ls (t = 2.07; P = 0.041). The differences on the validity scale K between the carriers of the ll and ss genotypes were also statistically significant (t = 2.49; P = 0.015). These results suggest that polymorphism of the serotonin transporter gene may be associated with the expression of schizoid traits (namely, social introversion, internal tension, weird thoughts and actions) in mentally healthy individuals. In the context of social adaptation, the personality profile configuration and data of statistical analysis indicate that the carriers of the ss genotype are more inclined to observe social norms than the carriers of the ll and ls genotypes. PMID:12760255

  2. Measurement of quasi-ballistic heat transport across nanoscale interfaces using ultrafast coherent soft x-ray beams

    SciTech Connect

    Siemens, M.; Li, Q.; Yang, R.; Nelson, K.; Anderson, E.; Murnane, M.; Kapteyn, H.

    2009-03-02

    Understanding heat transport on nanoscale dimensions is important for fundamental advances in nanoscience, as well as for practical applications such as thermal management in nano-electronics, thermoelectric devices, photovoltaics, nanomanufacturing, as well as nanoparticle thermal therapy. Here we report the first time-resolved measurements of heat transport across nanostructured interfaces. We observe the transition from a diffusive to a ballistic thermal transport regime, with a corresponding increase in the interface resistivity for line widths smaller than the phonon mean free path in the substrate. Resistivities more than three times higher than the bulk value are measured for the smallest line widths of 65 nm. Our findings are relevant to the modeling and design of heat transport in nanoscale engineered systems, including nanoelectronics, photovoltaics and thermoelectric devices.

  3. 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 ?g m-3 on average (absolute maximum of 6.2 ?g 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.

  4. An Analysis and Review of Measures and Relationships in Space Transportation Affordability

    NASA Technical Reports Server (NTRS)

    Zapata, Edgar; McCleskey, Carey

    2014-01-01

    The affordability of transportation to or from space is of continued interest across numerous and diverse stakeholders in our aerospace industry. Such an important metric as affordability deserves a clear understanding among stakeholders about what is meant by affordability, costs, and related terms, as otherwise it's difficult to see where specific improvements are needed or where to target specific investments. As captured in the famous words of Lewis Carroll, "If you don't know where you are going, any road will get you there". As important as understanding a metric may be, with terms such as costs, prices, specific costs, average costs, marginal costs, etc., it is equally important to understand the relationship among these measures. In turn, these measures intermingle with caveats and factors that introduce more measures in need of a common understanding among stakeholders. These factors include flight rates, capability, and payload. This paper seeks to review the costs of space transportation systems and the relationships among the many factors involved in costs from the points of view of diverse decision makers. A decision maker may have an interest in acquiring a single launch considering the best price (along with other factors in their business case), or an interest in many launches over time. Alternately, a decision maker may have a specific interest in developing a space transportation system that will offer certain prices, or flight rate capability, or both, at a certain up-front cost. The question arises for the later, to reuse or to expend? As it is necessary in thinking about the future to clearly understand the past and the present, this paper will present data and graphics to assist stakeholders in visualizing trends and the current state of affairs in the launch industry. At all times, raw data will be referenced (or made available separately) alongside detailed explanations about the data, so as to avoid the confusion or misleading conclusions that occur more often than not with complex graphs or statements when such context is lacking.

  5. 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...

  6. Wind-Tunnel Measurements of Effect of Dive-Recovery Flaps at Transonic Speeds on Models of a Seaplane and a Transport

    NASA Technical Reports Server (NTRS)

    Heath, Atwood R., Jr.; Ward, Robert J.

    1959-01-01

    The effects of wing-lower-surface dive-recovery flaps on the aero- dynamic characteristics of a transonic seaplane model and a transonic transport model having 40 deg swept wings have been investigated in the Langley 16-foot transonic tunnel. The seaplane model had a wing with an aspect ratio of 5.26, a taper ratio of 0.333, and NACA 63A series airfoil sections streamwise. The transport model had a wing with an aspect ratio of 8, a taper ratio of 0.3, and NACA 65A series airfoil sections perpendicular to the quarter-chord line. The effects of flap deflection, flap longitudinal location, and flap sweep were generally investigated for both horizontal-tail-on and horizontal-tail-off configurations. Model force and moment measurements were made for model angles of attack from -5 deg to 14 deg in the Mach number range from 0.70 to 1.075 at Reynolds numbers of 2.95 x 10(exp 6) to 4.35 x 10(exp 6). With proper longitudinal location, wing-lower-surface dive-recovery flaps produced lift and pitching-moment increments that increased with flap deflection. For the transport model a flap located aft on the wing proved to be more effective than one located more forward., both flaps having the same span and approximately the same deflection. For the seaplane model a high horizontal tail provided added effectiveness for the deflected-flap configuration.

  7. Neither crystalline nor amorphous: measuring disorder in polymers and assessing its effect on charge transport

    NASA Astrophysics Data System (ADS)

    Salleo, Alberto; Rivnay, Jonathan; Noriega, Rodrigo; Toney, Michael

    2012-02-01

    Conjugated polymers displaying high mobility are semicrystalline. Thin films of these materials are comprised of ordered regions (crystallites) and disordered regions. Because of the inherent anisotropy of polymers, the crystallites exhibit varying degrees of disorder in different directions. I will show a quantitative measurement of disorder as applied to these materials, which allows us to quantify a paracrystalline parameter g. This parameter can be used to rank polymers. I will show how g is related to the electronic structure of the polymer and with the presence of electronic traps in particular. By studying the dependence of g on molecular weight we can get to a definition of polymer behavior in an electronic transport sense.

  8. Revealing dissipationless chiral edge channel in magnetic topological insulator via non-local transport measurement

    NASA Astrophysics Data System (ADS)

    Lee, Wei-Li; Kou, Xufeng; Guo, Shih-Ting; Fan, Yabin; Pan, Lei; Lang, Murong; Jiang, Ying; Shao, Qiming; Nie, Tianxiao; Murata, Koichi; Tang, Jianshi; Wang, Yong; He, Liang; Lee, Ting-Kuo; Wang, Kang L.

    2015-03-01

    We observed quantum anomalous Hall effect (QAHE) in our 10-quintuple layer Cr-doped (BiSb)2Te3 film grown by MBE technique. The Hall resistance Rxy attains quantized value of h/e2 (25.8 k ?) as temperature drops below 85 mK. Unlike previous report in a thinner Cr-doped (BiSb)2Te3 film, a finite longitudinal resistance is found in the QAHE regime and remains non-zero up to 15 Tesla suggesting the coexistence of the chiral edge channel and certain dissipative conduction channel. From macroscopic non-local transport measurements with leads separated by few millimeters, we further identify the dissipationless nature of the chiral edge channel associated with the QAHE. Detailed T-dependence and field-dependence of the non-local signals will be presented and discussed.

  9. Low temperature transport measurements on atomically smooth metallic and oxygen deficient strontium titanate

    NASA Astrophysics Data System (ADS)

    Barquist, C. S.; Kwak, I. H.; Bauer, J.; Edmonds, T.; Biswas, A.; Lee, Y.

    2014-12-01

    Atomically smooth, TiO2 terminated SrTiO3 (STO) substrates were prepared using a combination of chemical and thermal annealing treatments. The TiO2 terminated surface was obtained by etching with aqua regia solution and thermal annealing at 1000 °C for 30 min. The subsequent vacuum annealing at 830 °C for 10 min generated an atomically smooth and metallic surface of STO. In this paper, we report low temperature transport measurements down to 50 mK on these samples which clearly exhibit a metallic temperature dependence in the resistance. The samples show no sign of superconductivity down to the lowest temperatures.The Rsquare(T) data provide information on the physical origin of metallic behavior in STO, which might also be relevant to the current research interest in oxide interfaces.

  10. 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.

  11. Earth strain measurements with the transportable laser ranging system: Field techniques and planning

    NASA Technical Reports Server (NTRS)

    Nakamura, Y.; Dorman, H. J.; Cahill, T.

    1982-01-01

    The potential of the transportable laser ranging system for monitoring the ground deformation around satellite ranging stations and other geodetic control points was examined with emphasis on testing the usefulness of the relative alteration technique. The temporal variation of the ratio of the length of each survey line to the mean length of all survey lines in a given area is directly related to the mean shear strain rate for the area. The data from a series of experimental measurements taken over the Los Angeles basin from a TLRS station at Mt. Wilson show that such ratios can be determined to an accuracy of one part in 10 million with a measurement program lasting for three days and without using any corrections for variations in atmospheric conditions. A numerical experiment using a set of hypothetical data indicates that reasonable estimates of the present shear strain rate and the direction of the principal axes in southern California can be deduced from such measurements over an interval of one to two years.

  12. Magnetic field measurements for study of fast electron transport in magnetized HED plasma

    NASA Astrophysics Data System (ADS)

    Sawada, Hiroshi; Griffin, Brandon; Presura, Radu; Haque, Showera; Sentoku, Yasuhiko

    2014-10-01

    Interaction of megagauss magnetic fields with high energy density (HED) plasma is of great interest in the field of magnetized plasma. The field changes fundamental properties of the HED plasma such as thermal and magnetic diffusion. A coupled capability utilizing the 1.0 MA Zebra pulsed power generator and the 50 TW Leopard laser at Nevada Terawatt Facility enables to create such a condition for studies of magnetized plasma properties. We have conducted an experiment to measure magnetic fields generated by a 1.0 MA, 100 ns Zebra pulsed current in stainless steel coils. Using a 532 nm continuous laser from a single longitudinal mode laser system, the temporal change in the magnetic field was measured with the Faraday rotation in F2 glass. The probe laser passing through the 1.5 mm in radius and 1.75 mm thick glass placed in the vicinity of the inductive coils was split with a Glan-Taylor prism to measure vertical and horizontal polarization components with photodiodes. We will present the analysis of the experimental result and a design of a coupled experiment for study of fast electron transport in the magnetized plasma.

  13. Classical and quantum phase transitions revealed using transport and x-ray measurements

    NASA Astrophysics Data System (ADS)

    Banerjee, Arnab

    I present the experimental studies of phase transitions in three different compounds in this thesis. The first one, SrCu2(BO3)2 is a physical realization of the Shastry-Sutherland model where, using precise lattice measurements, we examined the pressure-dependent phase diagram. We found two separate quantum phase transitions in the compound, the first one being a second order transition from a dimer to an intermediate magnetic state, and the second being a first order monoclinic distortion from the intermediate state to a presumed magnetically ordered state. In the second compound, NiS2, using a combination of transport and x-ray diffraction we proved that neither magnetism nor lattice symmetry, but rather electron-electron correlations, plays an active role in the insulator-metal phase transition in pure NiS2 under high pressure. Following this we make an attempt to delve the critical scaling laws using high pressure transport measurements in a helium dilution refrigerator. We observed a resistivity drop of over five orders and an effective of mass enhancement near the critical region. I detail the technical endeavors adopted for leading us to the critical behavior. The third compound, TbTe3, was believed to show only one charge density wave (CDW). We discovered a second CDW, but at a much lower transition temperature to the first one. Our results pointed to bidirectional ordering in TbTe3, a compound that has been otherwise considered a canonical model for one-dimensional CDW physics. The order parameter for this new CDW appears to deviate from standard mean-field behavior. This is only the second rare-earth telluride for which a q-vector has been determined for a second CDW, and the first for which the temperature dependence of that q-vector was characterized.

  14. CALIPSO Measurements of Saharan Dust Properties near Source and Transport Regions

    NASA Astrophysics Data System (ADS)

    Omar, A. H.; Liu, Z.; Tackett, J. L.; Vaughan, M.; Trepte, C. R.; Winker, D. M.

    2014-12-01

    The Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) mission, a collaboration between NASA and Centre National d'Études Spatiales (CNES), was launched in April 2006 to provide vertically resolved measurements of cloud and aerosol distributions. The primary instrument on the CALIPSO satellite is the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP), a near-nadir viewing two-wavelength polarization-sensitive instrument. The unique nature of CALIOP measurements make it quite challenging to validate backscatter profiles, aerosol type, and cloud phase, all of which are used to retrieve extinction and optical depth. We exploit the large data set generated by CALIPSO between 2006 - 2013 to determine a multi-year climatology of the properties of Saharan dust, in particular seasonal optical depths, layer frequencies, and layer heights of Saharan dust gridded in accordance with the Level 3 data products protocol. The data are screened using standard CALIPSO quality assurance flags, cloud aerosol discrimination (CAD) scores, overlying features and layer properties. To evaluate the effects of transport on the morphology, vertical extent and size of Saharan dust layers, we compare probability distribution functions of the layer integrated volume depolarization ratios, geometric depths and integrated attenuated color ratios near the source (Lat 0o to 40o Lon -20o to 20o) to the same distributions in the far field or transport region (Lat 0o to 40o Lon -80o to -20o). To evaluate the uncertainty in the lidar ratios, we compare the values computed from dust layers overlying opaque water clouds, considered nominal, with the constant lidar ratio value used in the CALIOP algorithms for dust. We also explore the effects of noise on the CALIOP retrievals at daytime by comparing the distributions of the properties at daytime to the nighttime distributions.

  15. Aircraft measurements from Fennec: giant particles, optical properties, and effects of transport

    NASA Astrophysics Data System (ADS)

    Ryder, Claire; Rosenberg, Phil; Highwood, Ellie; McQuaid, Jim; Washington, Richard; Sodemann, Harald; Formenti, Paola; Marsham, John; Todd, Martin

    2015-04-01

    During June 2011 and 2012 the Fennec project took place in the Western Sahara desert. Ground based and airborne measurements were taken in remote desert regions of Mali, Mauritania and Algeria. In-situ aircraft measurements of Saharan dust from the 2011 flights will be presented, with size distributions extending to 300 ?m, representing measurements extending further into the coarse mode than previously published for airborne Saharan dust. A significant coarse mode was present in the size distribution measurements with effective diameter (deff) from 2.3 to 19.4 ?m and coarse mode volume median diameter (dvc) from 5.8 to 45.3 ?m. The mean size distribution had a larger relative proportion of coarse mode particles than previous aircraft measurements with significant contribution from the 'giant mode' - particles larger than 38 microns. Properties of dust size distribution and optical properties will be presented in relation to dust age since uplift and altitude. Vertical distributions of dust over desert (for both fresh and aged dust events) and the Eastern Atlantic Ocean from 42 aircraft profiles will be presented, demonstrating how size distributions and optical properties change during the early stages of the dust lifecycle. Size distributions show a loss of 60 to 90% of particles larger than 30 microns 12 h after uplift. Single scattering albedo increases from 0.92 to 0.94 to 0.95 between fresh, aged, and Eastern Atlantic dust profiles. Finally the impact of transport and changing optical properties on the radiative effect of dust will be examined.

  16. Entanglement entropy and Schmidt number as measures of delocalization of $?$ clusters in one-dimensional nuclear systems

    E-print Network

    Yoshiko Kanada-En'yo

    2015-01-27

    We calculated the von Neumann entanglement entropy and the Schmidt number of one dimentional (1D) cluster states and showed that these are useful measures to estimate entanglement caused by delocalization of clusters. We analyze system size dependence of these entanglement measures in the linear-chain $n\\alpha$ states given by Tohsaki-Horiuchi-Schuck-R\\"opke wave functions for 1D cluster gas states. We show that the Schmidt number is an almost equivalent measures to the von Neumann entanglement entropy when the delocalization of clusters occurs in the entire system but it shows different behaviors in a partially delocalized state containing localized clusters and delocalized ones. It means that the R\\'enyi-2 entanglement entropy, which relates to the Schmidt number, is found to be almost equivalent to the von Neumann entanglement entropy for the full delocalized cluster system but it is less sensitive to the partially delocalized cluster system than the von Neumann entanglement entropy. We also propose a new entanglement measure which has a generalized form of the Schmidt number. Sensitivity of these measures of entanglement to the delocalization of clusters in low-density regions was discussed.

  17. A comprehensive study of extended tetrathiafulvalene cruciform molecules for molecular electronics: synthesis and electrical transport measurements.

    PubMed

    Parker, Christian R; Leary, Edmund; Frisenda, Riccardo; Wei, Zhongming; Jennum, Karsten S; Glibstrup, Emil; Abrahamsen, Peter Bæch; Santella, Marco; Christensen, Mikkel A; Della Pia, Eduardo Antonio; Li, Tao; Gonzalez, Maria Teresa; Jiang, Xingbin; Morsing, Thorbjørn J; Rubio-Bollinger, Gabino; Laursen, Bo W; Nørgaard, Kasper; van der Zant, Herre; Agrait, Nicolas; Nielsen, Mogens Brøndsted

    2014-11-26

    Cruciform-like molecules with two orthogonally placed ?-conjugated systems have in recent years attracted significant interest for their potential use as molecular wires in molecular electronics. Here we present synthetic protocols for a large selection of cruciform molecules based on oligo(phenyleneethynylene) (OPE) and tetrathiafulvalene (TTF) scaffolds, end-capped with acetyl-protected thiolates as electrode anchoring groups. The molecules were subjected to a comprehensive study of their conducting properties as well as their photophysical and electrochemical properties in solution. The complex nature of the molecules and their possible binding in different configurations in junctions called for different techniques of conductance measurements: (1) conducting-probe atomic force microscopy (CP-AFM) measurements on self-assembled monolayers (SAMs), (2) mechanically controlled break-junction (MCBJ) measurements, and (3) scanning tunneling microscopy break-junction (STM-BJ) measurements. The CP-AFM measurements showed structure-property relationships from SAMs of series of OPE3 and OPE5 cruciform molecules; the conductance of the SAM increased with the number of dithiafulvene (DTF) units (0, 1, 2) along the wire, and it increased when substituting two arylethynyl end groups of the OPE3 backbone with two DTF units. The MCBJ and STM-BJ studies on single molecules both showed that DTFs decreased the junction formation probability, but, in contrast, no significant influence on the single-molecule conductance was observed. We suggest that the origins of the difference between SAM and single-molecule measurements lie in the nature of the molecule-electrode interface as well as in effects arising from molecular packing in the SAMs. This comprehensive study shows that for complex molecules care should be taken when directly comparing single-molecule measurements and measurements of SAMs and solid-state devices thereof. PMID:25375316

  18. Simultaneous measurement of cosmology and intrinsic alignments using joint cosmic shear and galaxy number density correlations

    Microsoft Academic Search

    Benjamin Joachimi; S. L. Bridle

    2010-01-01

    Aims: Cosmic shear is a powerful method to constrain cosmology, provided that any systematic effects are under control. The intrinsic alignment of galaxies is expected to severely bias parameter estimates if not taken into account. We explore the potential of a joint analysis of tomographic galaxy ellipticity, galaxy number density, and ellipticity-number density cross-correlations to simultaneously constrain cosmology and self-calibrate

  19. 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. [Los Alamos National Lab., NM (United States). Electronics Materials and Device Research Group

    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.

  20. Correlated biofilm imaging, transport and metabolism measurements via combined nuclear magnetic resonance and confocal microscopy.

    PubMed

    McLean, Jeffrey S; Ona, Ositadinma N; Majors, Paul D

    2008-02-01

    Bacterial biofilms are complex, three-dimensional communities found nearly everywhere in nature and are also associated with many human diseases. Detailed metabolic information is critical to understand and exploit beneficial biofilms as well as combat antibiotic-resistant, disease-associated forms. However, most current techniques used to measure temporal and spatial metabolite profiles in these delicate structures are invasive or destructive. Here, we describe imaging, transport and metabolite measurement methods and their correlation for live, non-invasive monitoring of biofilm processes. This novel combination of measurements is enabled by the use of an integrated nuclear magnetic resonance (NMR) and confocal laser scanning microscope (CLSM). NMR methods provide macroscopic structure, metabolic pathway and rate data, spatially resolved metabolite concentrations and water diffusion profiles within the biofilm. In particular, current depth-resolved spectroscopy methods are applied to detect metabolites in 140-190 nl volumes within biofilms of the dissimilatory metal-reducing bacterium Shewanella oneidensis strain MR-1 and the oral bacterium implicated in caries disease, Streptococcus mutans strain UA159. The perfused sample chamber also contains a transparent optical window allowing for the collection of complementary fluorescence information using a unique, in-magnet CLSM. In this example, the entire three-dimensional biofilm structure was imaged using magnetic resonance imaging. This was then correlated to a fluorescent CLSM image by employing a green fluorescent protein reporter construct of S. oneidensis. Non-invasive techniques such as described here, which enable measurements of dynamic metabolic processes, especially in a depth-resolved fashion, are expected to advance our understanding of processes occurring within biofilm communities. PMID:18253132

  1. Correlated biofilm imaging, transport and metabolism measurements via combined nuclear magnetic resonance and confocal microscopy

    PubMed Central

    McLean, Jeffrey S; Ona, Ositadinma N; Majors, Paul D

    2015-01-01

    Bacterial biofilms are complex, three-dimensional communities found nearly everywhere in nature and are also associated with many human diseases. Detailed metabolic information is critical to understand and exploit beneficial biofilms as well as combat antibiotic-resistant, disease-associated forms. However, most current techniques used to measure temporal and spatial metabolite profiles in these delicate structures are invasive or destructive. Here, we describe imaging, transport and metabolite measurement methods and their correlation for live, non-invasive monitoring of biofilm processes. This novel combination of measurements is enabled by the use of an integrated nuclear magnetic resonance (NMR) and confocal laser scanning microscope (CLSM). NMR methods provide macroscopic structure, metabolic pathway and rate data, spatially resolved metabolite concentrations and water diffusion profiles within the biofilm. In particular, current depth-resolved spectroscopy methods are applied to detect metabolites in 140–190 nl volumes within biofilms of the dissimilatory metal-reducing bacterium Shewanella oneidensis strain MR-1 and the oral bacterium implicated in caries disease, Streptococcus mutans strain UA159. The perfused sample chamber also contains a transparent optical window allowing for the collection of complementary fluorescence information using a unique, in-magnet CLSM. In this example, the entire three-dimensional biofilm structure was imaged using magnetic resonance imaging. This was then correlated to a fluorescent CLSM image by employing a green fluorescent protein reporter construct of S. oneidensis. Non-invasive techniques such as described here, which enable measurements of dynamic metabolic processes, especially in a depth-resolved fashion, are expected to advance our understanding of processes occurring within biofilm communities. PMID:18253132

  2. Nature's Microfluidic Transporter: Rotational Cytoplasmic Streaming at High Peclet Numbers Jan-Willem van de Meent,1

    E-print Network

    Goldstein, Raymond E.

    transverse to the cylinder's long axis, akin to Dean vortices at finite Reynolds numbers, arises from by the tonoplast membrane, which regulates the exchange of metabolites with the vacuole [12]. Shear generated

  3. Measuring and modeling of a three-dimensional tracer transport in a planted soil column

    NASA Astrophysics Data System (ADS)

    Schroeder, N.; Javaux, M.; Haber-Pohlmeier, S.; Pohlmeier, A. J.; Huber, K.; Vereecken, H.; Vanderborght, J.

    2013-12-01

    Water flow from soil to root is driven by the plant transpiration and an important component of the hydrological cycle. The model R-SWMS combines three-dimensional (3D) water flow and solute transport in soil with a detailed description of root structure in three dimensions [1,2]. This model offers the possibility to calculate root water and solute uptake and flow within the roots, which enables explicit studies with respect to the distribution of water and solutes around the roots as well as local processes at the root-soil interface. In this study, we compared measured data from a tracer experiment using Magnetic Resonance Imaging (MRI) with simulations in order to assess the distribution and magnitude of the water uptake of a young lupine plant. An aqueous solution of the Gadolinium-complex (Gd-DTPA2-) was chosen as a tracer, as it behaves conservatively and is ideally suited for MRI. Water flow in the soil towards the roots can thus be visualized by following the change in tracer concentrations over time. The data were obtained by MRI, providing high resolution 3D images of the tracer distribution and root architecture structures by using a spin echo pulse sequence, which is strongly T1- weighted to be tracer sensitive [3], and T2 -weighted for root imaging [4]. This experimental setup was simulated using the 3D high-resolution numerical model R-SWMS. The comparison between MRI data and the simulations showed extensive effects of root architecture parameters on solute spreading. Although the results of our study showed the strength of combining non-invasive measurements and 3D modeling of solute and water flow in soil-root systems, where the derivation of plant hydraulic parameters such as axial and radial root conductivities is possible, current limitations were found with respect to MRI measurements and process description. [1] Javaux, M., T. Schröder, J. Vanderborght, and H. Vereecken (2008), Use of a Three-Dimensional Detailed Modeling Approach for Predicting Root Water Uptake, Vadose Zone Journal, 7(3), 1079-1079. [2] Schröder, N., M. Javaux, J. Vanderborght, B. Steffen, and H. Vereecken (2012), Effect of Root Water and Solute Uptake on Apparent Soil Dispersivity: A Simulation Study, Vadose Zone Journal, 11(3). [3 ]Haber-Pohlmeier, S., Bechtold, M., Stapf, S., and Pohlmeier, A. (2010). Water Flow Monitored by Tracer Transport in Natural Porous Media Using Magnetic Resonance Imaging. Vadose Zone Journal (9),835-845. [4] Stingaciu, L. R., Schulz, H., Pohlmeier, A., Behnke, S., Zilken, H., Vereecken, H., and Javaux, M. (2013). In Situ Root System Architecture Extraction from Magnetic Resonance Imaging for Application to Water Uptake Modeling. Vadose Zone Journal.

  4. Phase averaged measurements of the coherent structure of a Mach number 0.6 jet 

    E-print Network

    Emami, Saied

    1983-01-01

    , phase averaged measurements of the axial mass velocity, radial velocity, and the product of the two 'nave been made. These measurements yield information about the percent of the total fluctuations contained in the coherent structure. These measured... of St = 0. 474. The radial velocity fluctuations had a lower amolitude for both the full wave and chase averaged fluctuations compared to the axial mass velocity fluctuation. The Reynold's stresses tended to decay faster in amplitude than the axial...

  5. Transport Property Measurements in Doped Bi2Te3 Single Crystals Obtained via Zone Melting Method

    NASA Astrophysics Data System (ADS)

    Jariwala, Bhakti; Shah, Dimple; Ravindra, N. M.

    2015-06-01

    Single crystals of Se- and Fe-doped Bi2Te3 have been synthesized via the zone melting method. Energy-dispersive x-ray and x-ray powder diffraction analyses have been carried out to identify the constituent elements and determine the lattice parameters of the grown crystals. Surface topological features of the as-grown single crystals have been studied. The transport properties of doped stoichiometric Bi2Te3 single crystals have been studied by measuring the thermoelectric power and electrical conductivity in the temperature range from 303 K to 473 K. The thermoelectric power, S, effective mass, scattering parameter, and Fermi energy have been calculated from thermoelectric power measurements. The temperature dependence of the electrical conductivity, ?, shows that the dopants in the crystals are thermally activated. All the crystals exhibit semiconducting behavior as confirmed by the temperature dependence of ? and S. The effective mass of electrons and the effective density of states have been determined and are reported for Bi2Te3- x Se x (0 ? x ? 0.3) and Bi2- y Fe y Te3 (0 ? y ? 0.3).

  6. Transport measurement of Andreev bound states in a Kondo-correlated quantum dot.

    PubMed

    Kim, Bum-Kyu; Ahn, Ye-Hwan; Kim, Ju-Jin; Choi, Mahn-Soo; Bae, Myung-Ho; Kang, Kicheon; Lim, Jong Soo; López, Rosa; Kim, Nam

    2013-02-15

    We report nonequilibrium transport measurements of gate-tunable Andreev bound states in a carbon nanotube quantum dot coupled to two superconducting leads. In particular, we observe clear features of two types of Kondo ridges, which can be understood in terms of the interplay between the Kondo effect and superconductivity. In the first type (type I), the coupling is strong and the Kondo effect is dominant. Levels of the Andreev bound states display anticrossing in the middle of the ridge. On the other hand, crossing of the two Andreev bound states is shown in the second type (type II) together with the 0-? transition of the Josephson junction. Our scenario is well understood in terms of only a single dimensionless parameter, k(B)T(K)(min)/?, where T(K)(min) and ? are the minimum Kondo temperature of a ridge and the superconducting order parameter, respectively. Our observation is consistent with measurements of the critical current, and is supported by numerical renormalization group calculations. PMID:25166391

  7. 4He sample probe for combined microwave and dc transport measurements

    NASA Astrophysics Data System (ADS)

    Dobrovolskiy, Oleksandr V.; Franke, Jörg; Huth, Michael

    2015-03-01

    Combined microwave and dc electrical transport measurements at low temperatures represent a valuable experimental method in many research areas. In particular, when samples are conventional superconductors, a typical experiment requires a combination of helium temperatures, a wide range of magnetic fields, and the utilization of coaxial lines along with the usual dc wiring. We report on the general design features and the microwave performance of a custom-made low-temperature sample probe, with a measurement bandwidth tested from dc to 20 GHz. Equipped with six coaxial cables, a heater, Hall and temperature sensors, the probe fits into a ?32 mm shaft. We present our setup, analyze its microwave performance, and describe two representative experiments enabled by this system. The proposed setup will be essential for a systematic study of the dc and ac response of the vortex dynamics in nanopatterned superconductors subject to combined dc and microwave stimuli. Besides, it will be valuable for the investigation of a broad class of nonlinear stochastic systems where a combination of dc and high-frequency ac driving in a wide temperature range is necessary.

  8. Correlated Biofilm Imaging, Transport and Metabolism Measurements via Combined Nuclear Magnetic Resonance and Confocal Microscopy

    SciTech Connect

    Mclean, Jeffrey S.; Ona, Ositadinma; Majors, Paul D.

    2008-02-18

    Bacterial biofilms are complex, three-dimensional, communities that are found nearly everywhere in nature1 and are being recognized as the cause of treatment-resistant infections1 2. Advanced methods are required to characterize their collective and spatial patterns of metabolism however most techniques are invasive or destructive. Here we describe the use of a combined confocal laser scanning microscopy (CLSM) and nuclear magnetic resonance (NMR) microscopy system to monitor structure, mass transport, and metabolism in active biofilms. Non-invasive NMR methods provide macroscopic structure along with spatially-resolved metabolite profiles and diffusion measurements. CLSM enables monitoring of cells by fluorescent protein reporters to investigate biofilm structure and gene expression concurrently. A planar sample chamber design facilitates depth-resolved measurements on 140 nL sample volumes under laminar flow conditions. The techniques and approaches described here are applicable to environmental and medically relevant microbial communities, thus providing key metabolic information for promoting beneficial biofilms and treating associated diseases.

  9. Energy transport in short-pulse-laser-heated targets measured using extreme ultraviolet laser backlighting.

    PubMed

    Wilson, L A; Tallents, G J; Pasley, J; Whittaker, D S; Rose, S J; Guilbaud, O; Cassou, K; Kazamias, S; Daboussi, S; Pittman, M; Delmas, O; Demailly, J; Neveu, O; Ros, D

    2012-08-01

    The accurate characterization of thermal electron transport and the determination of heating by suprathermal electrons in laser driven solid targets are both issues of great importance to the current experiments being performed at the National Ignition Facility, which aims to achieve thermonuclear fusion ignition using lasers. Ionization, induced by electronic heat conduction, can cause the opacity of a material to drop significantly once bound-free photoionization is no longer energetically possible. We show that this drop in opacity enables measurements of the transmission of extreme ultraviolet (EUV) laser pulses at 13.9 nm to act as a signature of the heating of thin (50 nm) iron layers with a 50-nm thick parylene-N (CH) overlay irradiated by 35-fs pulses at irradiance 3×10(16) Wcm(-2). Comparing EUV transmission measurements at different times after irradiation to fluid code simulations shows that the target is instantaneously heated by hot electrons (with approximately 10% of the laser energy), followed by thermal conduction with a flux limiter of ?0.05. PMID:23005868

  10. Energy transport in short-pulse-laser-heated targets measured using extreme ultraviolet laser backlighting

    NASA Astrophysics Data System (ADS)

    Wilson, L. A.; Tallents, G. J.; Pasley, J.; Whittaker, D. S.; Rose, S. J.; Guilbaud, O.; Cassou, K.; Kazamias, S.; Daboussi, S.; Pittman, M.; Delmas, O.; Demailly, J.; Neveu, O.; Ros, D.

    2012-08-01

    The accurate characterization of thermal electron transport and the determination of heating by suprathermal electrons in laser driven solid targets are both issues of great importance to the current experiments being performed at the National Ignition Facility, which aims to achieve thermonuclear fusion ignition using lasers. Ionization, induced by electronic heat conduction, can cause the opacity of a material to drop significantly once bound-free photoionization is no longer energetically possible. We show that this drop in opacity enables measurements of the transmission of extreme ultraviolet (EUV) laser pulses at 13.9 nm to act as a signature of the heating of thin (50 nm) iron layers with a 50-nm thick parylene-N (CH) overlay irradiated by 35-fs pulses at irradiance 3×1016 Wcm-2. Comparing EUV transmission measurements at different times after irradiation to fluid code simulations shows that the target is instantaneously heated by hot electrons (with approximately 10% of the laser energy), followed by thermal conduction with a flux limiter of ?0.05.

  11. Major transport mechanisms of pyrethroids in residential settings and effects of mitigation measures.

    PubMed

    Davidson, Paul C; Jones, Russell L; Harbourt, Christopher M; Hendley, Paul; Goodwin, Gregory E; Slizy, Bradley A

    2014-01-01

    The major pathways for transport of pyrethroids were determined in runoff studies conducted at a full-scale test facility in central California, USA. The 6 replicate house lots were typical of front lawns and house fronts of California residential developments and consisted of stucco walls, garage doors, driveways, and residential lawn irrigation sprinkler systems. Each of the 6 lots also included a rainfall simulator to generate artificial rainfall events. Different pyrethroids were applied to 5 surfaces—driveway, garage door and adjacent walls, lawn, lawn perimeter (grass near the house walls), and house walls above grass. The volume of runoff water from each house lot was measured, sampled, and analyzed to determine the amount of pyrethroid mass lost from each surface. Applications to 3 of the house lots were made using the application practices typically used prior to recent label changes, and applications were made to the other 3 house lots according to the revised application procedures. Results from the house lots using the historic application procedures showed that losses of the compounds applied to the driveway and garage door (including the adjacent walls) were 99.75% of total measured runoff losses. The greatest losses were associated with significant rainfall events rather than lawn irrigation events. However, runoff losses were 40 times less using the revised application procedures recently specified on pyrethroid labels. PMID:24105831

  12. 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…

  13. A participatory approach to the identification of measures of number sense in children prior to school entry

    Microsoft Academic Search

    Sally Howell; Coral Kemp

    2009-01-01

    The research reported in this paper used a modified Delphi procedure in an attempt to establish a consensus on tasks proposed to assess components of number sense identified as essential for early mathematics success by a broad range of academics with expertise in the area of early mathematics. Tasks included as measures of these components were based on assessment tasks

  14. Nonintrusive electron number density measurements in the plume of a 1 kW arcjet using a modern microwave interferometer

    Microsoft Academic Search

    Shawn G. Ohler; Brian E. Gilchrist; Alec D. Gallimore

    1995-01-01

    Reported is the use of a microwave interferometric technique for making nonintrusive measurements of plasma electron number density in the plume of a space electric propulsion thruster. The technique is capable of providing good sensitivity and accuracy as well as resolution using modern microwave network analyzer technology. Density profiles were obtained throughout the plume of a 1 kW hydrogen arcjet

  15. Anharmonic effects on a phonon-number measurement of a quantum-mesoscopic-mechanical D. H. Santamore

    E-print Network

    Roukes, Michael L.

    of oscillation for each oscillator. One NEMS oscillator is driven and strongly damped and becomes a transducerAnharmonic effects on a phonon-number measurement of a quantum-mesoscopic-mechanical oscillator D mechanical oscillator. In this scheme two NEMS oscillators are coupled via a term quadratic in the amplitude

  16. Grant Title: AERA-ETS FELLOWSHIP PROGRAM IN MEASUREMENT AND EDUCATION RESEARCH Funding Opportunity Number: N/A

    E-print Network

    Farritor, Shane

    Grant Title: AERA-ETS FELLOWSHIP PROGRAM IN MEASUREMENT AND EDUCATION RESEARCH Funding Opportunity Number: N/A Agency/Department: American Educational Research Association (AERA) in collaboration Educational Research Association (AERA) and Educational Testing Service (ETS) announce the AERA-ETS Fellowship

  17. The basic reproductive number of Ebola and the effects of public health measures: the cases of Congo and Uganda

    Microsoft Academic Search

    Gerardo Chowell; Nick W. Hengartner; Carlos Castillo-Chavez; Paul W. Fenimore; J. M. Hyman

    2004-01-01

    Despite improved control measures, Ebola remains a serious public health risk in African regions where recurrent outbreaks have been observed since the initial epidemic in 1976. Using epidemic modeling and data from two well-documented Ebola outbreaks (Congo 1995 and Uganda 2000), we estimate the number of secondary cases generated by an index case in the absence of control interventions R0.

  18. Measurement of Large-Scale Sediment Transport Dynamics Using Multibeam Sonar

    NASA Astrophysics Data System (ADS)

    Simmons, S. M.; Parsons, D. R.; Best, J. L.; Malzone, C.; Keevil, G.

    2007-12-01

    Multibeam Echo-Sounder (MBES) sonar systems have developed rapidly over recent decades and are now routinely deployed to provide high-resolution object detection and bathymetric surveying in a range of aquatic environments, from the deep-sea to lakes and rivers. MBES systems were developed for bottom-detection and measurement of bed morphology, and have previously discarded the received acoustic back-scatter from the water column after the bottom-detection algorithms have been performed. However, modern data handling and storage technologies have facilitated the logging of this large quantity of acoustic intensity and phase information, and commercial MBES systems are now available that provide this capability. This paper develops a novel methodology to exploit this logging capability to quantify the concentration and dynamics of suspended sediment within the water column. This development provides a multi-purpose tool for the holistic surveying of sediment transport by imaging suspended sediment concentration, associated coherent flow structures and providing concurrent high-resolution bathymetry. This paper presents methods of data analysis and results obtained from deployment of the RESON SeaBat 8125 and 7125 MBES systems in the field and during testing in a controlled environment. The field results were obtained from sites on the Paraná river, Argentina, with the aim of examining the dynamics of suspended sediment transport over dune bedforms and in the region of flow mixing between large rivers of significantly different suspended sediment concentration. Controlled testing was performed in a former ship dry-dock by creating flows density currents of known suspended sediment concentration with different types and mixes of sediment. The results demonstrate the capability of the RESON MBES systems to successfully resolve the contrast in suspended sediment concentration, and hence the spatio-temporal monitoring of the associated coherent flow structures. The results demonstrate the ability of MBES systems to obtain large sets of data across a two-dimensional swath: this enables the real-time monitoring of suspended sediment transport and related flow processes on a scale previously unrealisable with single-beam acoustic back-scatter systems.

  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

    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 ?-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. 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 ?-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

  1. Characterization of long-range transported Saharan dust across the Atlantic Ocean; dual-wavelength lidar measurements during SALTRACE

    NASA Astrophysics Data System (ADS)

    Gross, Silke; Freudenthaler, Volker; Schäfler, Andreas; Schepanski, Kerstin; Heinold, Bernd; Toledano, Carlos; Wiegner, Matthias; Weinzierl, Bernadett

    2015-04-01

    Mineral dust is a major component of the atmospheric aerosol load which main source region is the Saharan desert. Dust layers can be transported over thousands of kilometers and thus they cannot be considered as regional phenomenon. During long-range transport the particles are influenced by aging and mixing processes altering the microphysical and thus the optical properties of Saharan dust. But the influence of long-range transport on the particle properties and their effect on the Earth's radiation budget is still not well understood. To study aging processes of transported Saharan dust as well as the microphysical, optical and radiative properties of long-range transported dust the Saharan Aerosol Long-range Transport and Aerosol-Cloud-Interaction Experiment (SALTRACE) took place at Barbados in June and July 2013. SALTRACE was designed as closure study combining ground-based and airborne lidar and in-situ measurements with Satellite observations, long-term measurements at Barbados, and model calculations. During SALTRACE four main dust events occurred with column integrated AOD of up to 0.6. The vertical aerosol distribution was characterized by a three layer structure consisting of a marine dominated boundary layer, a highly variable mixing layer often affected by clouds, and a Saharan dust layer in heights between 2 km and 3.5 km in some cases even up to 5 km. We will present first results of the ground-based measurements with the dual-wavelength lidar system POLIS of the Meteorological Institute of the Ludwig-Maximilians Universität, München. In particular we will investigate measurements of the particle linear depolarization ratio and the lidar ratio of the different aerosol layers. We compare our findings with results of the Saharan Mineral Dust Experiment (SAMUM) studying Saharan dust close to the source region in Morocco and at the beginning of the long-range transport on the Cape Verde Islands. In addition, we assess the influence of long-range transport on the optical properties of Saharan dust by combining lidar measurements with analyses of active dust source regions and processes during dust transport.

  2. Performance Measurement for Public Services in Academic and Research Libraries. Occasional Paper Number #9.

    ERIC Educational Resources Information Center

    Cronin, Mary J.

    This paper defines performance measurement as the clarification of objectives and standards, identification of key activities, data collection and analysis, and formative evaluation of services. It then examines some of the factors involved in using performance measurement to evaluate public services activities, and analyzes performance…

  3. 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

  4. Rounding of pumice clasts during transport: field measurements and laboratory studies

    NASA Astrophysics Data System (ADS)

    Manga, Michael; Patel, Ameeta; Dufek, Josef

    2011-04-01

    Volcanic clasts in many pyroclastic density current deposits are notably more round than their counterparts in corresponding fall deposits. This increase in roundness and sphericity reflects different degrees of comminution, abrasion and breakup during transport. We performed experimental measurements to determine an empirical relationship between particle shape and mass loss caused by particle-particle interactions. We consider, as examples, pumice from four volcanoes: Medicine Lake, California; Lassen, California; Taupo, New Zealand; Mount St Helens, Washington. We find that average sample roundness reaches a maximum value once particles lose between 15% and 60% of their mass. The most texturally homogeneous clasts (Taupo) become the most round. Crystal-rich pumice abrades more slowly than crystal-free pumice of similar density. Abrasion rates also decrease with time as particles become less angular. We compare our experimental measurements with the shapes of clasts in one of the May 18, 1980 pyroclastic density current units at Mount St Helens, deposited 4-8 km from the vent. The measured roundness of these clasts is close to the experimentally determined maximum value. For a much smaller deposit from the 1915 Lassen eruption, clast roundness is closer to the value for pumice in fall deposits and suggests that only a few volume percent of material was removed from large clasts. In neither field deposit do we see a significant change in roundness with increasing distance from the vent. We suggest that this trend is recorded because much of the rounding and ash production occur in proximal regions where the density currents are the most energetic. As a result, all clasts that are deposited have experienced similar amounts of comminution in the proximal region, and similar amounts of abrasion as they settle through the dense, near-bed region prior to final deposition.

  5. Measuring the similarity of target volume delineations independent of the number of observers

    NASA Astrophysics Data System (ADS)

    Kouwenhoven, Erik; Giezen, Marina; Struikmans, Henk

    2009-05-01

    The variability of target delineations is a topic of interest in radiotherapy. The similarity of delineations is often quantified by use of a conformity index (CI) defined as the ratio of common to encompassing volume. Several forms of CI are in use, but no consensus exists on how to calculate the CI for more than two delineations. This study proposes a generalization of the CI applicable to any number of delineations. The generalization of the CI was developed, unbiased with respect to the number of delineations. Numerical values were calculated for clinical and theoretical cases, and differences with other forms of CI were considered. A simple expression could be derived, applicable to any number of delineations, and is equivalent to the known CI for two delineations. The use of this index is advised, although another frequently used index obtained from averaging the CI between all possible pairs of delineations results in minor differences. The use of the third generalization for the CI which is based upon the volume common to all delineations shows a clear dependence upon the number of delineations and is discouraged.

  6. Measuring the similarity of target volume delineations independent of the number of observers.

    PubMed

    Kouwenhoven, Erik; Giezen, Marina; Struikmans, Henk

    2009-05-01

    The variability of target delineations is a topic of interest in radiotherapy. The similarity of delineations is often quantified by use of a conformity index (CI) defined as the ratio of common to encompassing volume. Several forms of CI are in use, but no consensus exists on how to calculate the CI for more than two delineations. This study proposes a generalization of the CI applicable to any number of delineations. The generalization of the CI was developed, unbiased with respect to the number of delineations. Numerical values were calculated for clinical and theoretical cases, and differences with other forms of CI were considered. A simple expression could be derived, applicable to any number of delineations, and is equivalent to the known CI for two delineations. The use of this index is advised, although another frequently used index obtained from averaging the CI between all possible pairs of delineations results in minor differences. The use of the third generalization for the CI which is based upon the volume common to all delineations shows a clear dependence upon the number of delineations and is discouraged. PMID:19384002

  7. 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.

  8. Outline of experimental schemes for measurements of thermophysical and transport properties in warm dense matter at GSI and FAIR

    NASA Astrophysics Data System (ADS)

    Tauschwitz, Anna; Basko, Mikhail; Efremov, Vladimir; Iosilevskiy, Igor; Jacoby, Joachim; Maruhn, Joachim; Neumayer, Paul; Novikov, Vladimir; Tauschwitz, Andreas; Rosmej, Frank

    2010-08-01

    Different experimental schemes for investigation of warm dense matter produced with intense energetic ion beams are presented. The described target configurations allow direct measurements of thermophysical and transport properties of warm dense matter without hydrodynamic recalculations. The presented experiments will be realized at the current GSI synchrotron SIS-18 and the future FAIR facility in the framework of the WDM-collaboration.

  9. Use of high-temperature gas-tight electrochemical cells to measure electronic transport and thermodynamics in metal oxides

    Microsoft Academic Search

    J. H. Park; B. Ma; E. T. Park

    1997-01-01

    By using a gas-tight electrochemical cell, the authors can perform high-temperature coulometric titration and measure electronic transport properties to determine the electronic defect structure of metal oxides. This technique reduces the time and expense required for conventional thermogravimetric measurements. The components of the gas-tight coulometric titration cell are an oxygen sensor, Pt\\/yttria stabilized zirconia (YSZ)\\/Pt, and an encapsulated metal oxide

  10. Performance of british university psychology departments as measured by number of publications in BPS journals

    Microsoft Academic Search

    Andrew M. Colman; Sonya P. Grant; Emma Henderson

    1992-01-01

    The aim of this investigation was to gauge the comparative research performance of university departments of psychology in\\u000a Britain. The performance indicator was the number of publications per departmental staff member in the journals of the British\\u000a Psychological Society (BPS) during the seven-year period 1983–1989. The contents of these journals were thoroughly searched,\\u000a and articles written by members of university

  11. Repeatability of measures of inflammatory cell number in bronchial biopsies in atopic asthma

    Microsoft Academic Search

    J. K. Sont; L. N. A. Willems; C. E. Evertse; R. Hooijer; P. J. Sterk

    1997-01-01

    Airway pathology is increasingly considered to be a major outcome in asthma research. The aim of this study was to examine the intra-observer, with- in-section and between-biopsy repeatability, together with the implications for sta- tistical power of a computerized quantitative analysis of inflammatory cell numbers in the lamina propria in bronchial biopsy specimens from atopic asthmatic subjects. Thirty six atopic

  12. Simultaneous measurement of cosmology and intrinsic alignments using joint cosmic shear and galaxy number density correlations

    NASA Astrophysics Data System (ADS)

    Joachimi, B.; Bridle, S. L.

    2010-11-01

    Aims: Cosmic shear is a powerful method to constrain cosmology, provided that any systematic effects are under control. The intrinsic alignment of galaxies is expected to severely bias parameter estimates if not taken into account. We explore the potential of a joint analysis of tomographic galaxy ellipticity, galaxy number density, and ellipticity-number density cross-correlations to simultaneously constrain cosmology and self-calibrate unknown intrinsic alignment and galaxy bias contributions. Methods: We treat intrinsic alignments and galaxy biasing as free functions of scale and redshift and marginalise over the resulting parameter sets. Constraints on cosmology are calculated by combining the likelihoods from all two-point correlations between galaxy ellipticity and galaxy number density. The information required for these calculations is already available in a standard cosmic shear data set. We include contributions to these functions from cosmic shear, intrinsic alignments, galaxy clustering and magnification effects. Results: In a Fisher matrix analysis we compare our constraints with those from cosmic shear alone in the absence of intrinsic alignments. For a potential future large area survey, such as Euclid, the extra information from the additional correlation functions can make up for the additional free parameters in the intrinsic alignment and galaxy bias terms, depending on the flexibility in the models. For example, the dark energy task force figure of merit is recovered even when more than 100 free parameters are marginalised over. We find that the redshift quality requirements are similar to those calculated in the absence of intrinsic alignments.

  13. SEM technique for imaging and measuring electronic transport in nanocomposites based on electric field induced contrast

    DOEpatents

    Jesse, Stephen (Knoxville, TN) [Knoxville, TN; Geohegan, David B. (Knoxville, TN) [Knoxville, TN; Guillorn, Michael (Brooktondale, NY) [Brooktondale, NY

    2009-02-17

    Methods and apparatus are described for SEM imaging and measuring electronic transport in nanocomposites based on electric field induced contrast. A method includes mounting a sample onto a sample holder, the sample including a sample material; wire bonding leads from the sample holder onto the sample; placing the sample holder in a vacuum chamber of a scanning electron microscope; connecting leads from the sample holder to a power source located outside the vacuum chamber; controlling secondary electron emission from the sample by applying a predetermined voltage to the sample through the leads; and generating an image of the secondary electron emission from the sample. An apparatus includes a sample holder for a scanning electron microscope having an electrical interconnect and leads on top of the sample holder electrically connected to the electrical interconnect; a power source and a controller connected to the electrical interconnect for applying voltage to the sample holder to control the secondary electron emission from a sample mounted on the sample holder; and a computer coupled to a secondary electron detector to generate images of the secondary electron emission from the sample.

  14. High CO2 emissions through porous media: Transport mechanisms and implications for flux measurement and fractionation

    USGS Publications Warehouse

    Evans, William C.; Sorey, M.L.; Kennedy, B.M.; Stonestrom, D.A.; Rogie, J.D.; Shuster, D.L.

    2001-01-01

    Diffuse emissions of CO2 are known to be large around some volcanoes and hydrothermal areas. Accumulation-chamber measurements of CO2 flux are increasingly used to estimate the total magmatic or metamorphic CO2 released from such areas. To assess the performance of accumulation chamber systems at fluxes one to three orders of magnitude higher than normally encountered in soil respiration studies, a test system was constructed in the laboratory where known fluxes could be maintained through dry sand. Steady-state gas concentration profiles and fractionation effects observed in the 30-cm sand column nearly match those predicted by the Stefan-Maxwell equations, indicating that the test system was functioning successfully as a uniform porous medium. Eight groups of investigators tested their accumulation chamber equipment, all configured with continuous infrared gas analyzers (IRGA), in this system. Over a flux range of ~ 200-12,000 g m-2 day-1, 90% of their 203 flux measurements were 0-25% lower than the imposed flux with a mean difference of - 12.5%. Although this difference would seem to be within the range of acceptability for many geologic investigations, some potential sources for larger errors were discovered. A steady-state pressure gradient of -20 Pa/m was measured in the sand column at a flux of 11,200 g m-2 day-1. The derived permeability (50 darcies) was used in the dusty-gas model (DGM) of transport to quantify various diffusive and viscous flux components. These calculations were used to demonstrate that accumulation chambers, in addition to reducing the underlying diffusive gradient, severely disrupt the steady-state pressure gradient. The resultant diversion of the net gas flow is probably responsible for the systematically low flux measurements. It was also shown that the fractionating effects of a viscous CO2 efflux against a diffusive influx of air will have a major impact on some important geochemical indicators, such as N2/Ar, ??15N-N2, and 4He/22Ne. Published by Elsevier Science B.V.

  15. Reversing the weak measurement of an arbitrary field with finite photon number 

    E-print Network

    Sun, Qingqing; Al-Amri, M.; Zubairy, M. Suhail.

    2009-01-01

    ,m=0nmax #1;nme?#1;n+m#2;#2;t#6;n#7;#8;m#6; according to the quantum trajectory theory, where 2#2; is the photon decay rate in the cavity and t is the duration of the measurement. Here we ignore all the normalization con- stants for simplicity until... the end of the derivation. For finite time this measurement is not sharp since any Fock compo- nent could give null result. To reverse the weak measure- ment, we need to swap the components symmetrically to #5;n,m=0nmax #1;nme?#1;n+m#2;#2;t#6;N?n#7...

  16. New gauge fields from extension of space time parallel transport of vector spaces to the underlying number systems.

    SciTech Connect

    Benioff, P. (Physics)

    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.

  17. Improving stratospheric transport trend analysis based on SF6 and CO2 measurements

    NASA Astrophysics Data System (ADS)

    Ray, Eric A.; Moore, Fred L.; Rosenlof, Karen H.; Davis, Sean M.; Sweeney, Colm; Tans, Pieter; Wang, Tao; Elkins, James W.; Bönisch, Harald; Engel, Andreas; Sugawara, Satoshi; Nakazawa, T.; Aoki, S.

    2014-12-01

    In this study we reexamine nearly four decades of in situ balloon-based stratospheric observations of SF6 and CO2 with an idealized model and reanalysis products. We use new techniques to account for the spatial and temporal inhomogeneity of the sparse balloon profiles and to calculate stratospheric mean ages of air more consistently from the observations with the idealized model. By doing so we are able to more clearly show and account for the variability of mean age of air throughout the bulk of the depth of the stratosphere. From an idealized model guided by the observations, we identify variability in the mean age due to the seasonal cycle of stratospheric transport, the quasi-biennial oscillation in tropical zonal winds, major volcanic eruptions, and linear trends that vary significantly with altitude. We calculate a negative mean age trend in the lowest 5 km of the stratosphere that agrees within uncertainties with a trend calculated from a set of chemistry climate model mean ages in this layer. The mean age trends reverse sign in the middle and upper stratosphere and are in agreement with a previous positive trend estimate using the same observational data set, although we have substantially reduced the uncertainty on the trend. Our analysis shows that a long time series of in situ profile measurements of trace gases such as SF6 and CO2 can be a unique and useful indicator of stratospheric circulation variability on a range of time scales and an important contributor to help validate the stratospheric portion of global chemistry climate models. However, with only SF6 and CO2 measurements, the competing effects on mean age between mean circulation and mixing (tropical entrainment) are not uniquely separable.

  18. Promoter methylation of serotonin transporter gene is associated with obesity measures: a monozygotic twin study

    PubMed Central

    Zhao, J; Goldberg, J; Vaccarino, V

    2013-01-01

    Objective: Epigenetic mechanisms are increasingly being recognized as an important factor for obesity. The serotonin transporter gene (SLC6A4) has a critical role in regulating food intake, body weight and energy balance. This study examines the potential association between SLC6A4 promoter methylation and obesity measures in a monozygotic (MZ) twin sample. Methods: We studied 84 MZ twin pairs drawn from the Vietnam Era Twin Registry. Obesity measures include body mass index (BMI), body weight, waist circumference (WC) and waist-hip ratio (WHR). The SLC6A4 promoter methylation profile in peripheral blood leukocytes was quantified by bisulfite pyrosequencing. The association between methylation variation and obesity parameters was examined by mixed-model regression and matched pair analysis, adjusting for age, smoking, alcohol consumption, physical activity and total daily energy intake. Multiple testing was controlled using the adjusted false discovery rate (q-value). Results: Mean methylation level was positively correlated with BMI (r=0.29; P=0.0002), body weight (r=0.31; P<0.0001) and WC (r=0.20; P=0.009), but not WHR. Intra-pair differences in mean methylation were significantly correlated with intra-pair differences in BMI, body weight and WC, but not WHR. On average, a 1% increase in mean methylation was associated with 0.33?kg?m?2 increase in BMI (95% CI: 0.02–0.65; P=0.03), 1.16?kg increase in body weight (95% CI, 0.16–2.16; P=0.02) and 0.78?cm increase in WC (95% CI, 0.05–1.50; P=0.03) after controlling for potential confounders. Conclusions: SLC6A4 promoter hypermethylation is significantly associated with an increased prevalence of obesity within a MZ twin study. PMID:22290534

  19. PHYSICAL REVIEW A VOLUME 51, NUMBER 2 FEBRUARY 1995 Dynamics of quantum collapse in energy measurements

    E-print Network

    Presilla, Carlo

    measurements Ubaldo Tambini Dipartimento di Fisica, Universita di Ferrara, and Istituto Nazionale di Fisica Nucleare, Sezione di Ferrara, Vha ParaChao 12, Ferrara, Italy $/100 Carlo Presilla Dipartimento di Fisica, Universita di Roma "La Sapienza, "and Istituto Nazionale di Fisica Nucleare, Sezione di Roma, Piazzale A

  20. VOLUME 15, NUMBER 2, 2005 LINCOLN LABORATORY JOURNAL New Measures of Effectiveness for Human Language Technology

    E-print Network

    by the Defense Advanced Research Projects Agency and the Defense Language Institute under Air Force Contract FA project involving Lincoln Laboratory, the MIT Department of Brain and Cognitive Sciences, and the Defense for Human Language Technology New Measures of Effectiveness for Human Language Technology n Research

  1. Beyond mobile number portability: measuring consumer preferences for service portability in Japan's mobile phone market

    Microsoft Academic Search

    Takanori Ida

    2012-01-01

    Japan's mobile phone market has been oligopolized by three incumbents who are seeking vertically integrated business models, which may prevent competitors from using platform layers to provide original services. We conduct two types of conjoint analysis to measure consumer stated preferences and draw two main conclusions from the analyses. First, the average consumer is willing to pay more than JPY

  2. Beyond mobile number portability: measuring consumer preferences for service portability in Japan's mobile phone market

    Microsoft Academic Search

    Takanori Ida

    2011-01-01

    Japan's mobile phone market has been oligopolized by three incumbents who are seeking vertically integrated business models, which may prevent competitors from using platform layers to provide original services. We conduct two types of conjoint analysis to measure consumer stated preferences and draw two main conclusions from the analyses. First, the average consumer is willing to pay more than JPY

  3. Daytime Image Measurement and Reconstruction for Space Situational Awareness Applications (Paper ID number 4231324)

    Microsoft Academic Search

    M. Roggemann; D. Douglas; E. Therkildsen; D. Archambeault; R. Maeda; D. Schultz; B. Wheeler

    2010-01-01

    An operational technology for imaging satellites during the daytime hours would vastly increase the ability of optical space situational awareness (SSA) systems to gather information about satellites. During the day the atmospheric seeing is generally worse than in terminator, and the contribution of sky background noise to the image measurement is significant. We have developed a straightforward model for estimating

  4. WIND Measurements of Proton and Alpha Particle Flow and Number Density J. T. Steinberg

    E-print Network

    Richardson, John

    for investigating the interplanetary edium. The solar wind experiment (SWE) on WIND e e includes 2 Faraday cup-alpha particle differential flow can s a be determined. We present early SWE Faraday cup result nd compare proton detectors for measuring th nergy/charge spectrum of solar wind protons and alpha f t particles. The Faraday

  5. A procedure for detecting the number of signal components in a radar measurement

    Microsoft Academic Search

    Pinyuen Chen; Michael C. Wicks

    2000-01-01

    This paper uses statistical selection theory to detect the multiplicity of the smallest eigenvalue of the covariance matrix, computed using measured multichannel multipulse radar data. We propose a selection procedure to estimate the multiplicity and value of the smallest eigenvalue(s). We derive the probability of a correct selection, P(CS), and the least favorable configuration (LFC) for our procedures. Under the

  6. Ion Doppler Spectroscopy, Far Infrared Interferometry and Measuring the Lundquist Number on HIT-SI

    Microsoft Academic Search

    R. G. O'Neill; R. J. Smith; A. J. Redd; C. Akcay; R. A. Hosn; T. R. Jarboe; M. Nagata

    2006-01-01

    Ion Doppler Spectroscopy (IDS) is used to measure ion velocity and temperature on HIT-SI. The spectrometer uses a 16 channel photo multiplier to track temperature and velocity continuously through the discharge. The spectrometer can view into the HIT-SI injector region as well as into the equilibrium region. Temperature and velocity data will be presented. A tangentially viewing far infrared (FIR)

  7. Spatially resolved in situ measurements of the transport of organic molecules in a polycrystalline nanoporous membrane

    E-print Network

    Nair, Sankar

    of photoacoustic signal generation from a heterogeneous membrane, allows extraction of concentration profiles. This capability would constitute a powerful way of studying membrane transport, providing a completely transport and converted into a thermoacoustic signal originating from a cumulative region of the sample down to a certain

  8. Pesticide Transport with Runoff from Fairway Turf: Measured Compared to Modeled

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pesticides applied to turf grass have been detected in surface waters raising concerns of their affect on water quality and interest in their source, hydrological transport and use of models to predict transport. TurfPQ, a pesticide runoff model for turf grass, was evaluated to determine its ability...

  9. The measurable heat flux that accompanies active transport Dick Bedeauxw and Signe Kjelstrupw

    E-print Network

    Kjelstrup, Signe

    that the chemical reaction as well as the ion transports are activated, and that the enzyme has a temperature by a temperature drop. A prescription has been given for how to determine transport coefficients on the mesocopic in biological systems has been described in several ways. Most common is to picture the various enzyme states

  10. Effect of sidewall conductance on heat-transport measurements for turbulent Rayleigh-Benard convection

    E-print Network

    Fygenson, Deborah Kuchnir

    -Be´nard convection Guenter Ahlers Department of Physics and iQUEST, University of California, Santa Barbara transport in Rayleigh-Be´nard convection the correction for the sidewall conductance is usually neglected convection of a fluid heated from below is the global heat transport of the system 1 , as expressed

  11. Nanopore Unitary Permeability Measured by Electrochemical and Optical Single Transporter Recording

    Microsoft Academic Search

    Roland Hemmler; Guido Böse; Richard Wagner; Reiner Peters

    2005-01-01

    For the analysis of membrane transport processes two single molecule methods are available that differ profoundly in data acquisition principle, achievable information, and application range: the widely employed electrical single channel recording and the more recently established optical single transporter recording. In this study dense arrays of microscopic horizontal bilayer membranes between 0.8?m and 50?m in diameter were created in

  12. Measures to Increase the Number of Mammary Artery Coronary Artery Anastomoses

    PubMed Central

    Tector, Alfred J.; Schmahl, Terence M.; Canino, Vincent R.

    1986-01-01

    Patients with single internal mammary artery (IMA) grafts along with saphenous vein grafts have been found to have fewer coronary events and longer survival after operation. To reduce bypass graft failure from intimal hyperplasia and atherosclerosis, as well as to improve results, three or more IMA grafts were placed in 215 patients from October 1982 through May 1985. Careful planning helped in bypassing the maximum number of coronary artery obstructions with arterial conduits. By using bilateral IMA grafts, sequential, and Y grafts, the number of IMA coronary artery anastomoses increases and the need for saphenous vein grafts decreases. Meticulous dissection and preparation of the entire IMA and proper construction of the anastomosis are essentials for these procedures to be successful. Two of the 215 patients died early and four died late. Ninety-five percent of the postoperative stress tests were negative and 92% of the 39 IMA grafts visualized in 13 patients studied postoperatively were patent. We found this to be a safe, challenging procedure that improved late bypass conduit success and prolonged survival. Images PMID:15226842

  13. 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

  14. Electron number density measurement by ruby laser interferometry in a CO2 laser-induced gas breakdown plasma

    Microsoft Academic Search

    T. K. Chu; L. C. Johnson; J. J. Schuss

    1977-01-01

    A pulsed ruby laser beam with 3 nsec full width at half magnitude is used to obtain space- and time-resolved, two-dimensional interferometic measurements of electron number density in CO laser produced plasma in hydrogen near the focal spot. The focal plane of the CO laser is arranged to be at the exit of a free-expansion jet, with the beam incident

  15. Tracking an unknown time-varying number of speakers using TDOA measurements: a random finite set approach

    Microsoft Academic Search

    Wing-Kin Ma; Ba-Ngu Vo; Sumeetpal S. Singh; Adrian J. Baddeley

    2006-01-01

    Speaker location estimation techniques based on time-difference-of-arrival (TDOA) measurements have attracted much attention recently. Many existing localization ideas assume that only one speaker is active at a time. In this paper, we focus on a more realistic assumption that the number of active speakers is unknown and time-varying. Such an assumption results in a more complex localization problem, and we

  16. Time-Resolved Measurements of Electron Number Density and Collision Frequency Using Microwave Attenuation and Phase Shift

    Microsoft Academic Search

    Mostofa Howlader; Yunqiang Yang; J. Reece Roth

    2003-01-01

    Microwave interferometry is a well-established non-perturbing plasma diagnostic technique. Compared with other diagnostic techniques, it is more robust and reliable in experimental applications. We describe an extended microwave interferometry technique to characterize the time-resolved electron number density and collision frequency of a fluorescent light tube plasma. This technique is based on a modern vector network analyzer and measures the attenuation

  17. Tomographic Particle Image Velocimetry Measurements of a High Reynolds Number Turbulent Boundary Layer

    NASA Astrophysics Data System (ADS)

    Atkinson, Callum; Stanislas, Michel; Soria, Julio

    2009-11-01

    Streamwise/wall-parallel volumes in the buffer region of a turbulent boundary layer at Re? =7800 and 11800 are measured using a 4 camera (2048 x 2048 px) tomographic particle image velocimetry (Tomo-PIV) system in the turbulent boundary layer wind tunnel at the Laboratoire de M'ecanique de Lille (LML). Measurement volumes of 1200 x 180 x 1200 pixels are achieved, the large boundary layer provided by this tunnel (?˜ 0.3 m) resulting in volumes of 470^+ x 70^+ x 470^+ and 920^+ x 140^+ x 920^+ wall units, respectively. The quality of the data acquired by this technique is assessed based on the mean velocity profile, velocity fluctuations, velocity power spectrum and the fluctuating divergence. Streaks and streamwise vortices are examined and an attempt is made to classify the flow using the invariants of the full velocity gradient tensor.

  18. An association between a dopamine transporter gene (SLC6A3) haplotype and ADHD symptom measures in nonclinical adults.

    PubMed

    Tong, Janette H S; Cummins, Tarrant D R; Johnson, Beth P; McKinley, Leigh-Anne; Pickering, Hayley E; Fanning, Peter; Stefanac, Nicole R; Newman, Daniel P; Hawi, Ziarih; Bellgrove, Mark A

    2015-03-01

    Previous genetic studies have postulated that attention deficit hyperactivity disorder (ADHD) should be regarded as the extreme end of a set of behavioural traits that can be continuously measured in the general population. The current study adopted a quantitative trait approach to examine the relationship between dopamine gene variants and self-reported ADHD symptoms in 517 nonclinical adults. Although genetic associations with variants of both the dopamine transporter (DAT1; SLC6A3) and D4 receptor (DRD4) genes have been reliably reported in children, results in adults are less consistent. We probed two potentially functional variable number of tandem repeat (VNTR) polymorphisms in the 3'UTR and intron 8 of DAT1, the 10-repeat and 6-repeat alleles of which respectively form a haplotype (10/6 DAT1 haplotype) that is associated with childhood ADHD. We also genotyped the exon 3 VNTR of DRD4, the 7-repeat allele of which is also an established risk factor for childhood ADHD. Permutation analysis showed an influence of the 10/6 DAT1 haplotype on both CAARS-G and CAARS-H (DSM-IV ADHD Symptoms Total and ADHD Index respectively), such that ADHD symptom scores increased with each additional copy of the 10/6 DAT1 haplotype. This result survived corrections for multiple comparisons both at the level of genotype and phenotype. A nominal association with CAARS-G was also found for the 7-repeat allele of the DRD4 VNTR however this did not survive multiple comparison correction. Our results provide further support for the influence of variation in the 10/6 DAT1 haplotype and individual differences in ADHD symptoms in adults. PMID:25656223

  19. Measured and modelled water transport in the Odra Estuary for the flood period July/August 1997

    NASA Astrophysics Data System (ADS)

    Rosenthal, W.; Wolf, T.; Witte, G.; Buchholz, W.; Rybaczok, P.

    1998-06-01

    The Szczecin Lagoon is an inshore water close to the Baltic Sea which can be subdivided into two major basins — the Kleines Haff in the western part of the lagoon and the Zalew Wielki (Großes Haff) in the eastern part. The lagoon has an area of A ? 685 km2 and an average depth D of ? 3.8 m. It drains into the Baltic Sea via three outlets — Peenestrom, Swina Strait and Dziwna. In summer 1997 one of the most severe floods ever recorded was running down the river. When this flood reached the lagoon, a monitoring network consisting of three fixed platforms already established delivered continous data recordings about environmental and water quality parameters. In addition, the research vessel Ludwig Prandtl was on a permanent cruise within the Zalew Wielki in order to complete the information delivered by the fixed measurement platforms. Recordings of conductivity taken by the fixed stations indicate a different behaviour of the two parts of the lagoon regarding water quality parameters. Whereas the flood water spread very quickly throughout the Zalew Wielki, the Kleines Haff was affected only with a remarkable time delay. Differences in water quality could be observed even by eye, showing clearly distinguishable colors in the different parts of the lagoon. ADCP measurements along different transects recorded by a ship-mounted current profiler gave valuable information about water exchange rates. For instance, the Odra river inflow had maximum discharge rates of about Q = 3000 m3/s. Discharge rates of the Swina Strait and Old Swina were also obtained. A three-dimensional hydrodynamical model (TRIM3D) was run in order to investigate the impact of the flood on the lagoon. The model was implemented on a grid with a spatial resolution ýx = 250 m giving a total number of 85000 grid points. Numerical simulations reproduced water level time series within the lagoon and gave good agreement between modelled and measured discharge rates. Transport paths and impact of the flood water body could be traced by use of this model.

  20. Entanglement entropy and Schmidt number as measures of delocalization of $\\alpha$ clusters in one-dimensional nuclear systems

    E-print Network

    Kanada-En'yo, Yoshiko

    2015-01-01

    We calculated the von Neumann entanglement entropy and the Schmidt number of one dimentional (1D) cluster states and showed that these are useful measures to estimate entanglement caused by delocalization of clusters. We analyze system size dependence of these entanglement measures in the linear-chain $n\\alpha$ states given by Tohsaki-Horiuchi-Schuck-R\\"opke wave functions for 1D cluster gas states. We show that the Schmidt number is an almost equivalent measures to the von Neumann entanglement entropy when the delocalization of clusters occurs in the entire system but it shows different behaviors in a partially delocalized state containing localized clusters and delocalized ones. It means that the R\\'enyi-2 entanglement entropy, which relates to the Schmidt number, is found to be almost equivalent to the von Neumann entanglement entropy for the full delocalized cluster system but it is less sensitive to the partially delocalized cluster system than the von Neumann entanglement entropy. We also propose a new ...

  1. Planar concentration and velocity measurements of a shock-accelerated gas curtain at multiple Mach numbers

    Microsoft Academic Search

    Greg Orlicz; B. J. Balakumar; Kathy Prestridge; Chris Tomkins

    2007-01-01

    Concentration and velocity measurements are obtained in a shock-accelerated gas curtain for three values of the incident shock strength: Ma = 1.2, 1.5, and 2.0. Qualitative PLIF images yield planar concentration maps at approximately 12 times to capture the evolution of the transitioning curtain, from which mixing widths are estimated as a function of time. The concentration results are complemented

  2. Visual stimulus parameters seriously compromise the measurement of approximate number system acuity and comparative effects between adults and children

    PubMed Central

    Sz?cs, Dénes; Nobes, Alison; Devine, Amy; Gabriel, Florence C.; Gebuis, Titia

    2013-01-01

    It has been suggested that a simple non-symbolic magnitude comparison task is sufficient to measure the acuity of a putative Approximate Number System (ANS). A proposed measure of the ANS, the so-called “internal Weber fraction” (w), would provide a clear measure of ANS acuity. However, ANS studies have never presented adequate evidence that visual stimulus parameters did not compromise measurements of w to such extent that w is actually driven by visual instead of numerical processes. We therefore investigated this question by testing non-symbolic magnitude discrimination in seven-year-old children and adults. We manipulated/controlled visual parameters in a more stringent manner than usual. As a consequence of these controls, in some trials numerical cues correlated positively with number while in others they correlated negatively with number. This congruency effect strongly correlated with w, which means that congruency effects were probably driving effects in w. Consequently, in both adults and children congruency had a major impact on the fit of the model underlying the computation of w. Furthermore, children showed larger congruency effects than adults. This suggests that ANS tasks are seriously compromised by the visual stimulus parameters, which cannot be controlled. Hence, they are not pure measures of the ANS and some putative w or ratio effect differences between children and adults in previous ANS studies may be due to the differential influence of the visual stimulus parameters in children and adults. In addition, because the resolution of congruency effects relies on inhibitory (interference suppression) function, some previous ANS findings were probably influenced by the developmental state of inhibitory processes especially when comparing children with developmental dyscalculia and typically developing children. PMID:23882245

  3. Insights into Stratospheric Chemistry and Transport from Ultra-fast Measurements in Rocket Plumes

    NASA Astrophysics Data System (ADS)

    Toohey, D.; Avallone, L.; Gates, A.; Thornton, B.; Richard, E.; Kelly, K.

    2001-12-01

    Fast-response measurements of reactive chlorine (Cl+ClO), carbon dioxide (CO2), ozone (O3) and methane (CH4) were obtained on a number of flights of the WB-57 aircraft into the plumes of rockets. These measurements occurred during the RISO and ACCENT missions in the plumes of the following rockets: Delta (May 1998 and April 1999), Atlas (June 1998 and April 1999), Athena (September 1999) and Space Shuttle (September 2000). These observations have provided a solid foundation for assessing the immediate post-launch impact of rocket exhaust on atmospheric ozone abundances. In addition, the time evolution of these species traces out the complex photochemistry of inorganic chlorine in the lower stratosphere in a way that allows us to examine the rates of key reactions that are important in the background stratosphere. The highly non-linear behavior of Cl and ClO at near-zero abundances of O3 as the plume ages and mixes with ambient air provides a unique window on small-scale (tens of meters) dynamical processes. In this talk we highlight the key observations that provide insight into important stratospheric photochemical and dynamical processes.

  4. Transportable distance measurement system based on superheterodyne interferometry using two phase-locked frequency-doubled Nd:YAG lasers.

    PubMed

    Azouigui, S; Badr, T; Wallerand, J-P; Himbert, M; Salgado, J; Juncar, P

    2010-05-01

    We describe a transportable distance measurement system based on synthetic wavelength interferometry. Two frequency-doubled Nd:yttrium aluminum garnet lasers at 532 nm are used to generate a synthetic wavelength of approximately 2.5 cm. A nonpolarizing interferometric system has been set up to eliminate polarization cross-talk issue. A superheterodyne detection was performed to measure the synthetic phase and to determine absolute distances. The capability to achieve fringe interpolation of 2pi/5600 has been demonstrated and an agreement in distance measurement at the 4 microm level has been achieved, compared to an optical interferometric 3 m long displacement bench. PMID:20515129

  5. 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.

  6. 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 disti

  7. Equation of state and transport property measurements of warm dense matter.

    SciTech Connect

    Knudson, Marcus D.; Desjarlais, Michael Paul

    2009-10-01

    Location of the liquid-vapor critical point (c.p.) is one of the key features of equation of state models used in simulating high energy density physics and pulsed power experiments. For example, material behavior in the location of the vapor dome is critical in determining how and when coronal plasmas form in expanding wires. Transport properties, such as conductivity and opacity, can vary an order of magnitude depending on whether the state of the material is inside or outside of the vapor dome. Due to the difficulty in experimentally producing states near the vapor dome, for all but a few materials, such as Cesium and Mercury, the uncertainty in the location of the c.p. is of order 100%. These states of interest can be produced on Z through high-velocity shock and release experiments. For example, it is estimated that release adiabats from {approx}1000 GPa in aluminum would skirt the vapor dome allowing estimates of the c.p. to be made. This is within the reach of Z experiments (flyer plate velocity of {approx}30 km/s). Recent high-fidelity EOS models and hydrocode simulations suggest that the dynamic two-phase flow behavior observed in initial scoping experiments can be reproduced, providing a link between theory and experiment. Experimental identification of the c.p. in aluminum would represent the first measurement of its kind in a dynamic experiment. Furthermore, once the c.p. has been experimentally determined it should be possible to probe the electrical conductivity, opacity, reflectivity, etc. of the material near the vapor dome, using a variety of diagnostics. We propose a combined experimental and theoretical investigation with the initial emphasis on aluminum.

  8. Optical measurements of soot size and number density in a complex flow, swirl-stabilized combustor

    SciTech Connect

    Samuelsen, G.S.; Wood, C.P.; Jackson, T.A.

    1984-01-01

    In-flame optical measurements of soot particulates in a turbulent, recirculating (i.e., complex flow) model laboratory combustor are described. A nonintrusive optical probe based on large angle (60 deg, 20 deg) intensity ratio scattering was used to yield a point measurement of particulate in the size range of 0.08 to 0.38 micrometers. The performance of the optical technique was evaluated, and an exploratory assessment of the spatial distribution of soot was conducted with attention to fuel molecular structure, fuel loading, and a smoke-suppressant additive (ferrocene). Isooctane and mixtures of isooctane with various ring and aromatic compounds blended to yield the smoke point of a JP-8 stock were prevaporized and introduced through a hollow cone nozzle. The addition of ring compounds to the base isooctane substantially changed the distribution of soot and increased the overall emission by 300%. The production of soot was substantially reduced by a decrease in fuel loading, and marginally reduced or not affected by the additive depending on fuel structure. The optical technique is a potentially powerful tool for providing the experimental evidence necessary to understand the processes of soot formation and burnout in complex flows typical of gas turbine combustors. However, scanning electron micrographs of extracted sample established that the technique is limited to the large particle wing of the soot size distribution, and optical and electronic processing can induce biasing and uncertainties which must be understood and controlled before the potential of the technique can be fulfilled.

  9. Dust transport over the eastern Mediterranean derived from Total Ozone Mapping Spectrometer, Aerosol Robotic Network, and surface measurements

    NASA Astrophysics Data System (ADS)

    Kalivitis, N.; Gerasopoulos, E.; Vrekoussis, M.; Kouvarakis, G.; Kubilay, N.; Hatzianastassiou, N.; Vardavas, I.; Mihalopoulos, N.

    2007-02-01

    Multiyear surface PM10 measurements performed on Crete Island, Greece, have been used in conjunction with satellite (Total Ozone Mapping Spectrometer (TOMS)) and ground-based remote sensing measurements (Aerosol Robotic Network (AERONET)) to enhance our understanding of the evolution of mineral dust events over the eastern Mediterranean. An analysis of southerly air masses at altitudes of 1000 and 3000 m over a 5 year period (2000-2005), showed that dust can potentially arrive over Crete, either simultaneously in the lower free troposphere and inside the boundary layer (vertical extended transport (VET)) or initially into the free troposphere with the heavier particles gradually being scavenged inside the boundary layer (free troposphere transport (FTT)). Both pathways present significant seasonal variations but on an annual basis contribute almost equally to the dust transport in the area. During VET the aerosol index (AI) derived from TOMS was significantly correlated with surface PM10, and in general AI was found to be adequate for the characterization of dust loadings over the eastern Mediterranean on a climatological basis. A significant covariance between PM10 and AOT was observed during VET as well, indicating that AOT levels from AERONET may be estimated by PM10 levels at the surface. Surface measurements are thus crucial for the validation of remote sensing measurements and hence are a powerful tool for the investigation of the impact of aerosols on climate.

  10. 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.

  11. Methodological aspects to be considered when measuring the approximate number system (ANS) – a research review

    PubMed Central

    Dietrich, Julia F.; Huber, Stefan; Nuerk, Hans-Christoph

    2015-01-01

    According to a dominant view, the approximate number system (ANS) is the foundation of symbolic math abilities. Due to the importance of math abilities for education and career, a lot of research focuses on the investigation of the ANS and its relationship with math performance. However, the results are inconsistent. This might be caused by studies differing greatly regarding the operationalization of the ANS (i.e., tasks, dependent variables). Moreover, many methodological aspects vary from one study to the next. In the present review, we discuss commonly used ANS tasks and dependent variables regarding their theoretical foundation and psychometric features. We argue that the inconsistent findings concerning the relationship between ANS acuity and math performance may be partially explained by differences in reliability. Furthermore, this review summarizes methodological aspects of ANS tasks having important impacts on the results, including stimulus range, visual controls, presentation duration of the stimuli and feedback. Based on this review, we give methodological recommendations on how to assess the ANS most reliably and most validly. All important methodological aspects to be considered when designing an ANS task or comparing results of different studies are summarized in two practical checklists. PMID:25852612

  12. Measurements of the transport gap in semiconducting multiwalled carbon nanotubes with varying diameter and length

    NASA Astrophysics Data System (ADS)

    Mtsuko, D.; Koshio, A.; Yudasaka, M.; Iijima, S.; Ahlskog, M.

    2015-05-01

    Low temperature transport in multiwalled carbon nanotubes (MWNTs) has been studied at different diameters and lengths, within 2 -10 nm , and 0.3 -3.5 ? m , respectively. In a majority of the samples, semiconductivity showed up as a transport gap in the gate voltage controlled conduction, but metallic MWNTs are found in all diameters. The transport gap is seen to be quantitatively determined by a diameter dependent band gap, and length dependent localization of charge carriers. The band gap of semiconducting MWNTs is estimated to be smaller than that extrapolated from the conventional expression applicable to semiconducting single wall carbon nanotubes. The results constitute a systematical study on size dependent transport and especially of semiconductivity in MWNTs.

  13. Measuring total longshore sediment transport with a LISST instrumented mini-sled. 

    E-print Network

    Huchzermeyer, Erick Karl

    2006-04-12

    A surf zone sediment transport study was conducted in Jamaica Beach, Texas, using new oceanographic equipment. A mini-sled was constructed and outfitted with an instrument package that consisted of two velocimeters, one current profiler, three OBS...

  14. Direct measurements of transport and water properties through the Bering Strait

    Microsoft Academic Search

    A. T. Roach; K. Aagaard; C. H. Pease; S. A. Salo; T. Weingartner; V. Pavlov; M. Kulakov

    1995-01-01

    Four years of temperature, salinity, and velocity data enable a direct computation of volume transport and a temporal description of water properties exchanged through the Bering Strait. The mean volume transport over the 4-year period (September 1990 through September 1994) is 0.83 Sv northward with a weekly standard deviation of 0.66 Sv. The maximum error in this mean estimate is

  15. Measurement of Cross-field Transport in a Magnetized Plasma Device

    SciTech Connect

    Oldenbuerger, S.; Lemoine, N.; Brochard, F.; Bonhomme, G. [Laboratoire de Physique des Milieux Ionises, Nancy Universite, BP 239, F-54506 Vandoeuvre-les-Nancy Cedex (France)

    2008-03-19

    Methods for the characterization of radial convective transport in magnetized plasma devices are depicted. Perspectives for the investigation of transport using the linear low-beta plasma device Mirabelle are presented. The utility of time resolved data analysis, using the wavelet transform of the signals, is demonstrated. These techniques are illustrated by their application to experimental data from the Mirabelle device and from the Castor tokamak.

  16. Wind tunnel measurement of boundary-layer response to sediment transport

    Microsoft Academic Search

    Cheryl McKenna Neuman; Marianne Maljaars

    1997-01-01

    This paper presents an empirical analysis of theboundary-layer response to sediment transport in awind tunnel with working section 0.7 × 0.76 × 12.5 m.With equilibrium transport, both the boundary-layer depth anddisplacement thickness increase relativeto clean air. The logarithmic expression of the Lawof the Wall provides a good description of thevelocity profile within the lower 20% of theboundary-layer depth, at least.

  17. Lateral subsurface stormflow and solute transport in a forested hillslope: A combined measurement and modeling approach

    NASA Astrophysics Data System (ADS)

    Laine-Kaulio, Hanne; Backnäs, Soile; Karvonen, Tuomo; Koivusalo, Harri; McDonnell, Jeffrey J.

    2014-10-01

    Preferential flow dominates water movement and solute transport in boreal forest hillslopes. However, only a few model applications to date have accounted for preferential flow at forest sites. Here we present a parallel and coupled simulation of flow and transport processes in the preferential flow domain and soil matrix of a forested hillslope section in Kangaslampi, Finland, using a new, three-dimensional, physically based dual-permeability model. Our aim is to simulate lateral subsurface stormflow and solute transport at the slope during a chloride tracer experiment, and to investigate the role of preferential flow in the tracer transport. The model was able to mimic the observed tracer transport during tracer irrigation, but overestimated the dilution velocity of the tracer plume in the highly conductive soil horizons near the soil surface after changing the irrigation to tracer-free water. According to the model, 140 times more chloride was transported downslope in the preferential flow domain than in the soil matrix during the tracer irrigation. The simulations showed, together with reference simulations with a traditional one pore domain model, that a two pore domain approach was required to simulate the observed flow and transport event. The event was characterized by the transmissivity feedback phenomenon and controlled by preferential flow mechanisms, in particular by lateral by-pass flow. According to our results, accounting for the slow-flow and fast-flow domains of soil, as well as the water and solute exchange between the domains, is essential for a successful simulation of flow and solute transport in preferential flow dominated hillslopes.

  18. Electroweak precision measurements in supersymmetric models with a U(1) R lepton number

    NASA Astrophysics Data System (ADS)

    Beauchesne, Hugues; Grégoire, Thomas

    2014-05-01

    As experimental constraints on the parameter space of the MSSM and close variations thereof become stronger, the motivation to explore supersymmetric models that challenge some of the standard assumptions of the MSSM also become stronger. For example, models where the gauginos are Dirac instead of Majorana have recently received more attention. Beside allowing for a supersoft SUSY breaking mechanism where the gauginos only provide finite threshold corrections to scalar masses, the cross section for the production of a squark pairs is reduced. In addition, Dirac gauginos can be used to build models that possess a U(1)R symmetry. This symmetry can then be identified with a lepton number, leading to models that are quite different from conventional scenarios. The sneutrinos in these models can acquire a vev and give mass to the leptons and the down-type squark. The phenomenology is novel, combining signatures that are typical of R-parity violating scenarios with signatures arising from leptoquarks. Correspondingly the constraints from electroweak precision data are also different. In these models, one of the leptons mixes with gauginos and superpotential Yukawa couplings can contribute to EWPM at tree level. In addition, lepton universality is broken. In this paper we adapt the operators analysis of Han and Skiba [1] to include the relevant violation of lepton universality, and do a global fit of the model to electroweak precision data, including all relevant tree-level and loop-level effects. We obtain bounds on the vev of the sneutrino and on the superpotential couplings of the model.

  19. Photocharge Transport and Recombination Measurements in Amorphous Silicon Films and Solar Cells by Photoconductive Frequency Mixing: Annual Subcontract Report, 20 April 1999 - 19 April 2000

    SciTech Connect

    Braunstein, R.; Kathwinkel, A.; Sheng, S. R. (University of California/Los Angeles)

    2001-08-29

    This report describes research focused on improving the individual component cells from which the multijunction devices are fabricated. The Mid-Bandgap and Metastability subteam and the Low-Bandgap subteam have the responsibility to develop appropriate materials for the respective layer of the triple-junction solar cell. To this end, it is necessary to characterize the materials that are prepared for the appropriate layer to optimize the devices and to develop an understanding of the conditions responsible for light-induced degradation so as to develop means to mitigate the degradation. Using the photomixing technique, UCLA was able to determine the mobility and lifetime separately of a number of semiconductor materials. We have established that different kinetics of degradation occur for mobility and lifetime. We have found that the drift mobility is electric-field dependent, and we developed a model for the charge transport through long-range potential fluctuations that enable a determination of the range and the depth of these fluctuations for material in the annealed and light-soaked states. UCLA has continued to provide transport parameters for the Mid-Gap, Metastability, and Low-Band teams. The materials studied were prepared by various deposition techniques. In phase II of this program, we investigated in detail the charge-transport properties by photomixing of a-Si:H, {mu}c-Si:H and a-SiGe:H alloy films prepared by hot-wire chemical vapor deposition (HWCVD) and plasma-enhanced chemical vapor deposition (PECVD) techniques, particularly under the conditions of high deposition rate and the transition from amorphous to microcrystalline state. Photomixing experiments were initiated to compare intrinsic film properties and device performance, and to study the impact of the changed contact geometry on the results of our photomixing measurements. We also attempted to employ the photomixing technique to measure the drift mobility of the transparent conducting oxide. Following our previous measurements of the transport parameters under hydrostatic pressure, we initiated the hydrostatic pressure dependence of small-angle X-ray scattering measurements to find the origin of the inelastic effect. Time-resolved photo- and thermoelectric effects (TTE) were used to simultaneously determine the thermal diffusivity, carrier lifetime, carrier mobility, and trap-level density in crystalline and amorphous Si (a-Si:H) and Si/Ge (a-Si/Ge:H) samples.

  20. 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

  1. 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.

  2. 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.

  3. VOLUME 87, NUMBER 18 P H Y S I C A L R E V I E W L E T T E R S 29 OCTOBER 2001 Electronic Transport in Metal Nanocrystal Arrays: The Effect

    E-print Network

    Jaeger, Heinrich M.

    ,6­8]. Us- ing newly developed self-assembly techniques, we have fabricated large highly ordered monolayers the impact of structural disorder on electronic transport in gold nanocrystal monolayers. Arrays ranging from of dodecanethiol-ligated gold nanocrystals on substrates with in-plane electrodes. Transport measurements

  4. Development of an urban inventory for road transport emissions of NO 2 and comparison with estimates derived from ambient measurements

    Microsoft Academic Search

    David C. Carslaw; Sean D. Beevers

    2005-01-01

    A primary nitrogen dioxide (NO2) emissions inventory has been developed for road transport sources in London based on recent exhaust emissions measurements of nitrogen oxides (NOX=NO+NO2) and NO2 from a range of vehicle types and technologies. The emissions inventory estimate of the mean primary volumetric NO2:NOX ratio (NO2 fraction) on road links in London was 10.2%. The emissions inventory highlights

  5. EVALUATION OF EUROPEAN ROAD TRANSPORT EMISSION MODELS AGAINST ON-ROAD EMISSION DATA AS MEASURED BY OPTICAL REMOTE SENSING

    Microsoft Academic Search

    Åke Sjödin; Martin Jerksjö

    A major on-road remote sensing emission measurement campaign was carried out in 2007 in Göteborg, Sweden, in order to provide on-road emission data for an evaluation of the three major road transport emission models in Europe, i.e. the COPERT 4 model, the Handbook of Emission Factors (HBEFA 2.1), and the recently developed ARTEMIS Road Model. The University of Denver's latest

  6. Measurements of classical transport of fast ions L. Zhao, W. W. Heidbrink, H. Boehmer, and R. McWilliams

    E-print Network

    Heidbrink, William W.

    -ion transport in a well controlled background plasma, a 3-cm diameter rf ion gun launches a pulsed, 300 e 1991 at UCLA. The parallel energy of the beam is measured by a two-grid energy analyzer at two axial locations z=0.32 m and z=6.4 m from the ion gun in LAPD. The calculated ion beam slowing-down time

  7. Comparing the results of bed load transport equations to field measurements in an Alpine river

    NASA Astrophysics Data System (ADS)

    Rascher, E.; Baewert, H.; Schmidt, K.-H.; Morche, D.

    2012-04-01

    Transport processes play a decisive role in fluvial systems when sediment is carried from source to sink. In a mountain river reach the morphologic development is basically determined by the bed load transport. Attempts to observe bed load entrainment and movement directly in the field are often complicated through difficulties in spatial and temporal variability and a necessary field effort. For this reason the development of sediment transport equations has a long history. A variety of such formulae has appeared since the first "modern" equation of DU BOYS (1879) was presented. Each of them is based on one of the following approaches: shear stress, stream discharge, stochastic function for sediment movement or stream power. Many of these equations have been developed on the basis of flume data or field data sets from specific river reaches. Therefore a critical consideration of their application to other natural streams is essential. A lack of available field data is undoubtedly the cause for a deficiency of such testing. (GOMEZ & CHURCH 1989; HABERSACK & LARONNE 2002; MARTIN 2003) In this study a selection of sediment transport equations is tested against data sets of 50 field observations from the Partnach River, in the Reintal Valley, Germany, in the years 2008-2011. At the outlet of this alpine catchment the channel bed is characterized by a gradient of 2 % and a median grain size of 24 mm. Bed load samples were taken using the Helley-Smith sampler at flow rates ranging from 1.0 - 5.9 m3/s. According to these data evaluations performance and feasibility of transport equations for field applications are checked. Up to now the results between observed and calculated transport rates show a large scatter of more than several orders of magnitude. This underlines the statements from GOMEZ AND CHURCH (1989) that most equations under/over predict transport rates if the basic requirements (steady flow, equilibrium load), which are usually assumed, are not fulfilled.

  8. Quantitative Measurements of Bedform Transport Rates and Sand Sheet Character in the Lower Mississippi River

    NASA Astrophysics Data System (ADS)

    Nittrouer, J. A.; Allison, M. A.; Campanella, R.

    2005-05-01

    Channel sand volume and downstream flux in the Mississippi River have important implications for proposed mitigation projects (dredging and pipelines) that seek to utilize this resource for replenishing neighboring barrier islands and restoring Louisiana's deteriorating wetlands. This study quantifies bedform migration-induced sand flux through the lower river on daily and seasonal timescales, and evaluates the sedimentary character of the bedload component. Observations and measurements were conducted along three study grids (Audubon Park, English Turn and Venice) over a range of river discharges between April 2003 and January 2005. Two multibeam bathymetric profiles of the study grids were conducted 24 h apart to document bedform migration, and stratigraphy and thickness of the sand layer were confirmed by CHIRP seismic profiling. Downstream transport is evaluated from bed elevation changes for a 1 m grid after correcting for river stage, and utilized to calculate bedload sand fluxes for larger, averaged grid cells after visual examination confirmed dunes had migrated <1 wavelength. Algorithms were formulated to remove spurious grid cells created by vessel motion, navigation and swath-matching errors. Initial data analysis indicates flux rates conform to expected trends: values are proportional to river discharge and are higher in the channel thalweg of straight reaches relative to shallower water. Bedform size also increases with river discharge and spatial changes in flux rates; height ranges from <1 m to 10 m, and wavelength from 10 m to 100 m. Seasonal trends in sand sheet thickness are evident, particularly in deeper meander reaches, where aggradation occurs at low flow and scour is observed during high flow. At highest discharges observed (35,000 m3/sec), bedform troughs bottom out on exposed relict fluvio-deltaic strata that the river has incised (i.e., sediment starved). A spatially uniform grab sampling effort (250 samples) provided grain size data of the active sand sheet for the lower 135 km of the river. A downstream trend of decreasing grain size (2.6 to 2.0 ?) is likely due to the finest sand fraction leaving suspension and becoming bedload as river gradient and velocity progressively decrease. Locally, grain size increases in the deepest portions of the channel as a result of enhanced flow scouring the fine and medium sand fraction.

  9. Measurements of the Shear Alfven Wave Dispersion for Finite Perpendicular Wave Number C. A. Kletzing,* S. R. Bounds, and J. Martin-Hiner

    E-print Network

    California at Los Angles, University of

    Measurements of the Shear Alfve´n Wave Dispersion for Finite Perpendicular Wave Number C. A for the regime in which VA ' VTe. By measuring the parallel phase velocity of the waves, the measurements can for these waves has been derived by several authors, direct experimental measurements to verify the dispersion

  10. Measurement of steady-state minority-carrier transport parameters in heavily doped n-type silicon

    NASA Technical Reports Server (NTRS)

    Del Alamo, Jesus A.; Swanson, Richard M.

    1987-01-01

    The relevant hole transport and recombination parameters in heavily doped n-type silicon under steady state are the hole diffusion length and the product of the hole diffusion coefficient times the hole equilibrium concentration. These parameters have measured in phosphorus-doped silicon grown by epitaxy throughout nearly two orders of magnitude of doping level. Both parameters are found to be strong functions of donor concentration. The equilibrium hole concentration can be deduced from the measurement. A rigid shrinkage of the forbidden gap appears as the dominant heavy doping mechanism in phosphorus-doped silicon.

  11. Opportunities for Air Pollutant and Greenhouse Gas Emission Reduction through Local Transport Planning

    Microsoft Academic Search

    F. Ruth Wood; Melissa Burgan; Steve Dorling; Rachel Warren

    2007-01-01

    This paper has three main objectives: firstly, to provide quantitative information on the potential greenhouse gas and air pollutant emissions reductions resulting from a number of future road transport scenarios; secondly, to illustrate the emission reduction measures available to local transport planners; and thirdly, to highlight the potential for these measures to be integrated into strategies that deliver other transport

  12. Time-Resolved Fluorescence Quenching Measurements of the Aggregation Numbers of Normal Sodium Alkyl Sulfate Micelles Well above the Critical Micelle Concentrations

    E-print Network

    Bales, Barney

    , because most of the interesting uses of micelles occur at finite micelle concentrations. For sodiumTime-Resolved Fluorescence Quenching Measurements of the Aggregation Numbers of Normal Sodium Alkyl, 1998 The aggregation numbers, NA, of normal sodium alkyl sulfate micelles were measured by time

  13. Using a qubit to measure photon-number statistics of a driven thermal oscillator A. A. Clerk and D. Wahyu Utami

    E-print Network

    Clerk, Aashish

    theoretically how photon-number statistics of a driven damped oscillator at finite tempera- ture canUsing a qubit to measure photon-number statistics of a driven thermal oscillator A. A. Clerk and D be extracted by measuring the dephasing spectrum of a two-level system dispersively coupled to the oscillator

  14. Direct Measurement of Room-Temperature Nondiffusive Thermal Transport Over Micron Distances in a Silicon Membrane

    NASA Astrophysics Data System (ADS)

    Johnson, Jeremy A.; Maznev, A. A.; Cuffe, John; Eliason, Jeffrey K.; Minnich, Austin J.; Kehoe, Timothy; Torres, Clivia M. Sotomayor; Chen, Gang; Nelson, Keith A.

    2013-01-01

    The “textbook” phonon mean free path of heat carrying phonons in silicon at room temperature is ˜40nm. However, a large contribution to the thermal conductivity comes from low-frequency phonons with much longer mean free paths. We present a simple experiment demonstrating that room-temperature thermal transport in Si significantly deviates from the diffusion model already at micron distances. Absorption of crossed laser pulses in a freestanding silicon membrane sets up a sinusoidal temperature profile that is monitored via diffraction of a probe laser beam. By changing the period of the thermal grating we vary the heat transport distance within the range ˜1-10?m. At small distances, we observe a reduction in the effective thermal conductivity indicating a transition from the diffusive to the ballistic transport regime for the low-frequency part of the phonon spectrum.

  15. Improvement of analysis precision upon the atomic number and electron density measurement by the dual x-ray CT

    NASA Astrophysics Data System (ADS)

    Imura, Yukino; Morii, Hisashi; Koike, Akifumi; Okunoyama, Takaharu; Neo, Yoichiro; Mimura, Hidenori; Aoki, Toru

    2010-08-01

    To identify the factor impairing the material identification parameters, which is provided by the dual-energy X-ray computed tomography method using a conventional X-ray tube and a CdTe detector, linear attenuation coefficient was measured by the radioactivity of radio isotopes and compared with theoretical figure. In our study, the atomic number and the electron density is calculated from the linear attenuation coefficient obtained in CT measurement by 64-channel CdTe line detector. To estimate accuracy of CdTe line sensor, it is needed to obtain the linear attenuation coefficient accurately. Using a single detector, the linear attenuation coefficient is verified for accuracy. The energy resolution of CdTe detectors and the method of reconstruction are discussed.

  16. 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

  17. Measurements of wind friction speeds over lava surfaces and assessment of sediment transport

    NASA Technical Reports Server (NTRS)

    Greeley, Ronald; Iversen, James D.

    1987-01-01

    Wind velocity profiles were obtained over alluvial plains, lava flows, and a cinder cone in the Mojave Desert to determine the wind shear and the potential for particle transport. It was found that aerodynamic roughness for winds increases nearly a factor of 5 as flow crosses from the alluvium to the lava surface, resulting in wind shear that is 21 percent greater. Thus, wind erosion and sand flux may be substantially enhanced over the lava field. Moreover, wind flow turbulence is enhanced in the wake of the cinder cone, which also increases erosion and sediment transportation by the wind.

  18. Measurement of Moisture Transport in the Membrane-Based Enthalpy Exchanger

    NASA Astrophysics Data System (ADS)

    Novotný, P.; Nguyen, V.; Dvo?ák, V.

    2013-04-01

    Application of moisture membrane system can increase the efficiency of the HVAC system where the latent heat load is responsible for a large fraction of total energy. The moisture transfer mechanisms in membranes were studied on our experimental device, which supplied dry air and humid air in two regime.The dry air and humid air were delivered to membrane-based enthalpy exchanger with two contraflow cavities separated by the examined membrane. Nine types of hydrophilic membranes were compared by efficiency of moisture transport during isothermal humidity transport for flow velocity from 0.5 to 4 ms-1

  19. Measurement of water transport during freezing in mammalian liver tissue: Part II--The use of differential scanning calorimetry.

    PubMed

    Devireddy, R V; Bischof, J C

    1998-10-01

    There is currently a need for experimental techniques to assay the biophysical response (water transport or intracellular ice formation, IIF) during freezing in the cells of whole tissue slices. These data are important in understanding and optimizing biomedical applications of freezing, particularly in cryosurgery. This study presents a new technique using a Differential Scanning Calorimeter (DSC) to obtain dynamic and quantitative water transport data in whole tissue slices during freezing. Sprague-Dawley rat liver tissue was chosen as our model system. The DSC was used to monitor quantitatively the heat released by water transported from the unfrozen cell cytoplasm to the partially frozen vascular/extracellular space at 5 degrees C/min. This technique was previously described for use in a single cell suspension system (Devireddy, et al. 1998). A model of water transport was fit to the DSC data using a nonlinear regression curve-fitting technique, which assumes that the rat liver tissue behaves as a two-compartment Krogh cylinder model. The biophysical parameters of water transport for rat liver tissue at 5 degrees C/min were obtained as Lpg = 3.16 x 10(-13) m3/Ns (1.9 microns/min-atm), ELp = 265 kJ/mole (63.4 kcal/mole), respectively. These results compare favorably to water transport parameters in whole liver tissue reported in the first part of this study obtained using a freeze substitution (FS) microscopy technique (Pazhayannur and Bischof, 1997). The DSC technique is shown to be a fast, quantitative, and reproducible technique to measure dynamic water transport in tissue systems. However, there are several limitations to the DSC technique: (a) a priori knowledge that the biophysical response is in fact water transport, (b) the technique cannot be used due to machine limitations at cooling rates greater than 40 degrees C/min, and (c) the tissue geometric dimensions (the Krogh model dimensions) and the osmotically inactive cell volumes Vb, must be determined by low-temperature microscopy techniques. PMID:10412432

  20. Contact-induced charge contributions to non-local spin transport measurements in Co/MgO/graphene devices

    NASA Astrophysics Data System (ADS)

    Volmer, Frank; Drögeler, Marc; Pohlmann, Tobias; Güntherodt, Gernot; Stampfer, Christoph; Beschoten, Bernd

    2015-06-01

    Recently, it has been shown that oxide barriers in graphene-based non-local spin-valve structures can be the bottleneck for spin transport. The barriers may cause spin dephasing during or right after electrical spin injection which limits spin transport parameters such as the spin lifetime of the whole device. An important task is to characterize the quality of the oxide barriers of both spin injection and detection contacts in a fabricated device. To address this issue, we discuss the influence of spatially inhomogeneous oxide barriers and especially conducting pinholes within the barriers on the background signal in non-local measurements of graphene/MgO/Co spin-valve devices. By both simulations and reference measurements on devices with non-ferromagnetic electrodes, we demonstrate that the background signal can be caused by an inhomogeneous current flow through the oxide barriers. As a main result, we demonstrate the existence of charge accumulation besides the actual spin accumulation signal in non-local voltage measurements, which can be explained by a redistribution of charge carriers by a perpendicular magnetic field similar to the classical Hall effect. Furthermore, we present systematic studies of the phase of the low frequency non-local ac voltage signal which is measured in non-local spin measurements when applying ac lock-in techniques. This phase has so far widely been neglected in the analysis of non-local spin transport. We demonstrate that this phase is another hallmark of the homogeneity of the MgO spin injection and detection barriers. We link backgate dependent changes of the phase to the interplay between the capacitance of the oxide barrier and the quantum capacitance of graphene.

  1. 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

  2. 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.

  3. Alterations in mitochondrial DNA copy number and the activities of electron transport chain complexes and pyruvate dehydrogenase in the frontal cortex from subjects with autism

    PubMed Central

    Gu, F; Chauhan, V; Kaur, K; Brown, W T; LaFauci, G; Wegiel, J; Chauhan, A

    2013-01-01

    Autism is a neurodevelopmental disorder associated with social deficits and behavioral abnormalities. Recent evidence suggests that mitochondrial dysfunction and oxidative stress may contribute to the etiology of autism. This is the first study to compare the activities of mitochondrial electron transport chain (ETC) complexes (I–V) and pyruvate dehydrogenase (PDH), as well as mitochondrial DNA (mtDNA) copy number in the frontal cortex tissues from autistic and age-matched control subjects. The activities of complexes I, V and PDH were most affected in autism (n=14) being significantly reduced by 31%, 36% and 35%, respectively. When 99% confidence interval (CI) of control group was taken as a reference range, impaired activities of complexes I, III and V were observed in 43%, 29% and 43% of autistic subjects, respectively. Reduced activities of all five ETC complexes were observed in 14% of autistic cases, and the activities of multiple complexes were decreased in 29% of autistic subjects. These results suggest that defects in complexes I and III (sites of mitochondrial free radical generation) and complex V (adenosine triphosphate synthase) are more prevalent in autism. PDH activity was also reduced in 57% of autistic subjects. The ratios of mtDNA of three mitochondrial genes ND1, ND4 and Cyt B (that encode for subunits of complexes I and III) to nuclear DNA were significantly increased in autism, suggesting a higher mtDNA copy number in autism. Compared with the 95% CI of the control group, 44% of autistic children showed higher copy numbers of all three mitochondrial genes examined. Furthermore, ND4 and Cyt B deletions were observed in 44% and 33% of autistic children, respectively. This study indicates that autism is associated with mitochondrial dysfunction in the brain. PMID:24002085

  4. Electron transport measurements of Schottky barrier inhomogeneities L. E. Calvet,a)

    E-print Network

    Reed, Mark

    on applied bias Va , 0 is the barrier height, and E00 is the reduced energy and related to Vg by E00 Vg q 2 nonmonotonicities in the low-temperature current versus gate voltage characteristics of PtSi/Si Schottky Barrier of the heterojunction. We thus demonstrate barrier height variations in electron transport through a relatively large

  5. Determination of wave growth from measured distribution functions and transport theory

    Microsoft Academic Search

    C. T. Dum; E. Marsch; W. Pilipp

    1980-01-01

    A stability analysis which directly uses particle distribution functions determined from experiments or transport theory, rather than model distributions, is carried out. The features of distribution functions relevant to whistlers, ion cyclotron waves, including their low-frequency extensions for propagation along the magnetic field, and to ion-acoustic waves are analyzed in detail. The dependence of wave growth on the precise shape

  6. Marine transportation of irradiated nuclear fuel, plutonium and radioactive wastes: the continuing debate on regulatory measures

    Microsoft Academic Search

    J. Wonham; C. M. Davies; V. G. Asimakopoulos; B. S. Tselentis

    2000-01-01

    The prospect that the maritime transportation of irradiated nuclear fuel (INF), plutonium and radioactive wastes can be expected to continue for the foreseeable future, together with widely expressed concern that an accident may occur to a ship carrying such cargo, has meant that regulatory safeguards have come under intense scrutiny in recent years. The paper describes the actions taken by

  7. The impact of automotive transportation on the environment and legislative measures for its control

    Microsoft Academic Search

    J. C. D. Blaine

    1972-01-01

    The central theme of this article relates to the legislative steps taken by the Government of the United States and its promulgation and enforcement of environmental quality standards in response to the nationwide concern with respect to the detrimental impact of automotive transportation upon the environment. Three aspects of this degrading impact are covered: pollution of the atmosphere by emissions

  8. Eddy-Induced Heat Transport in the Subtropical North Pacific from Argo, TMI, and Altimetry Measurements

    E-print Network

    Qiu, Bo

    . By analyzing historical moored in situ current meter and temperature records, Wunsch (1999) noted that eddy-core eddies tilt west- ward with decreasing depth. With the vertical shear of the mean zonal flow in tEddy-Induced Heat Transport in the Subtropical North Pacific from Argo, TMI, and Altimetry

  9. Implementing Innovatory Transport Measures: What Local Authorities in the UK Say About Their Problems and Requirements

    Microsoft Academic Search

    Angela Hull

    There is a growing emphasis on the need to secure an integrated transport system that both serves the needs of the economy and that contributes to a wider sustainability agenda which includes prudent use of natural resources and equitable access to jobs and facilities. Although the UK government has not set specific targets for emission reduction or accessibility for the

  10. Test-Retest Reliability of a Survey to Measure Transport-Related Physical Activity in Adults

    ERIC Educational Resources Information Center

    Badland, Hannah; Schofield, Grant

    2006-01-01

    The present research details test-retest reliability of a newly developed, telephone-administered TPA survey for adults. This instrument examines barriers, perceptions, and current travel behaviors to place of work/study and local convenience shops. Demonstrated test-retest reliability of the Active Friendly Environments-Transport-Related Physical…

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

    Microsoft Academic Search

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

    2010-01-01

    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

  12. Bio-plasma physics: Measuring Ion Transport Across Cell membranes with Plasmas

    NASA Astrophysics Data System (ADS)

    Gimmell, Jennifer; Sriram, Aditi; Gershman, Sophia; Post-Zwicker, Andrew

    2002-10-01

    A recent theoretical publication in the American Journal of Physics [1] investigates a mathematical model of plasma double layers, and their applicability to understanding ion transport across cell membranes. Cell membranes have selective permeability to the transport of different charged particles, similar to ion and electron movement across a double layer in a plasma. An existing voltage difference between the cells internal cytoplasm and the external bio-plasma causes a double layer to form between the cytoplasm and the bio-plasma. We present our design of a plasma created in a vessel with two distinct cross sections, similar to the model mentioned in the paper. When two plasmas of different cross sectional areas are considered, a double layer in the plasma forms on the interface between the two separate volumes. We use a Langmuir probe to evaluate plasma parameters such as electric potential, electric field, and charge density in the areas inside and surrounding the plasma double layer. These are used to show the similarity between charge transport across a plasma double layer, and ion transport across a cell membrane. [1] M. Uehara, K. K. Sakane, H.S. Maciel and W.I. Urruchi, "Physics and Biology: Bio-plasma physics," Am. J. Phys. 68 (5), 450-455 (2000).

  13. Semiquantitative RT-PCR measurement of gene expression in rat tissues including a correction for varying cell size and number

    PubMed Central

    Romero, Maria del Mar; Grasa, Maria del Mar; Esteve, Montserrat; Fernández-López, José Antonio; Alemany, Marià

    2007-01-01

    Background Current methodology of gene expression analysis limits the possibilities of comparison between cells/tissues of organs in which cell size and/or number changes as a consequence of the study (e.g. starvation). A method relating the abundance of specific mRNA copies per cell may allow direct comparison or different organs and/or changing physiological conditions. Methods With a number of selected genes, we analysed the relationship of the number of bases and the fluorescence recorded at a present level using cDNA standards. A lineal relationship was found between the final number of bases and the length of the transcript. The constants of this equation and those of the relationship between fluorescence and number of bases in cDNA were determined and a general equation linking the length of the transcript and the initial number of copies of mRNA was deduced for a given pre-established fluorescence setting. This allowed the calculation of the concentration of the corresponding mRNAs per g of tissue. The inclusion of tissue RNA and the DNA content per cell, allowed the calculation of the mRNA copies per cell. Results The application of this procedure to six genes: Arbp, cyclophilin, ChREBP, T4 deiodinase 2, acetyl-CoA carboxylase 1 and IRS-1, in liver and retroperitoneal adipose tissue of food-restricted rats allowed precise measures of their changes irrespective of the shrinking of the tissue, the loss of cells or changes in cell size, factors that deeply complicate the comparison between changing tissue conditions. The percentage results obtained with the present methods were essentially the same obtained with the delta-delta procedure and with individual cDNA standard curve quantitative RT-PCR estimation. Conclusion The method presented allows the comparison (i.e. as copies of mRNA per cell) between different genes and tissues, establishing the degree of abundance of the different molecular species tested. PMID:18039356

  14. Resolving the Impact of Biological Processes on DNAPL Transport in Unsaturated Porous Media through Nuclear Magnetic Resonance Relaxation Time Measurements

    SciTech Connect

    Hertzog, Russel; Geesey, Gill G.; White, Timothy A.; Ho, Clifford K.; Straley, Christian; Bryar, Traci R.; Seymour, Joseph; Codd, Sarah L.; Oram, Libbie

    2003-06-01

    This research leads to a better understanding of how physical and biological properties of porous media influence water and dense non-aqueous phase liquid (DNAPL) distribution under saturated and unsaturated conditions. Knowing how environmental properties affect DNAPL solvent flow in the subsurface is essential for developing models of flow and transport that are needed for designing remediation and long-term stewardship strategies. This project investigates the capability and limitations of low-field nuclear magnetic resonance (NMR) relaxation decay-rate measurements for determining environmental properties affecting DNAPL solvent flow in the subsurface. For in-situ subsurface environmental applications, lowfield proton NMR measurements are preferred to the conventional high-field techniques commonly used to obtain chemical shift data, because the low field measurements are much less degraded by the magnetic susceptibility variations between the rock grains and the pore fluid s that significantly interfere with the high-field NMR measurements. Our research scope includes determining whether DNAPLs exist in water-wet or solvent-wet environments, the pore-size distribution of the soils containing DNAPLs, and the impact of biological processes on their transport mechanisms in porous media. Knowledge of the in situ flow properties and pore distributions of organic contaminants are critical to understanding where and when these fluids will enter subsurface aquifers.

  15. Development of micro-four-point probe in a scanning tunneling microscope for in situ electrical transport measurement

    NASA Astrophysics Data System (ADS)

    Ge, Jian-Feng; Liu, Zhi-Long; Gao, Chun-Lei; Qian, Dong; Liu, Canhua; Jia, Jin-Feng

    2015-05-01

    Electrons at surface may behave differently from those in bulk of a material. Multi-functional tools are essential in comprehensive studies on a crystal surface. Here, we developed an in situ microscopic four-point probe (4PP) transport measurement system on the basis of a scanning tunneling microscope (STM). In particular, convenient replacement between STM tips and micro-4PPs enables systematic investigations of surface morphology, electronic structure, and electrical transport property of a same sample surface. Performances of the instrument are demonstrated with high-quality STM images, tunneling spectra, and low-noise electrical I-V characteristic curves of a single-layer FeSe film grown on a conductive SrTiO3 surface.

  16. Development of micro-four-point probe in a scanning tunneling microscope for in situ electrical transport measurement.

    PubMed

    Ge, Jian-Feng; Liu, Zhi-Long; Gao, Chun-Lei; Qian, Dong; Liu, Canhua; Jia, Jin-Feng

    2015-05-01

    Electrons at surface may behave differently from those in bulk of a material. Multi-functional tools are essential in comprehensive studies on a crystal surface. Here, we developed an in situ microscopic four-point probe (4PP) transport measurement system on the basis of a scanning tunneling microscope (STM). In particular, convenient replacement between STM tips and micro-4PPs enables systematic investigations of surface morphology, electronic structure, and electrical transport property of a same sample surface. Performances of the instrument are demonstrated with high-quality STM images, tunneling spectra, and low-noise electrical I-V characteristic curves of a single-layer FeSe film grown on a conductive SrTiO3 surface. PMID:26026532

  17. 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.

    2015-06-01

    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.

  18. Advances in the measurement and computation of thermal phonon transport properties

    NASA Astrophysics Data System (ADS)

    Minnich, A. J.

    2015-02-01

    Heat conduction by phonons is a ubiquitous process that incorporates a wide range of physics and plays an essential role in applications ranging from space power generation to LED lighting. Heat conduction has been studied for over two hundred years, yet many of the microscopic details have remained unknown in most crystalline solids, including which phonon–phonon interactions are primarily responsible for thermal resistance and how heat is distributed among the broad thermal spectrum. This lack of knowledge was the result of limitations on the available tools to study heat conduction. However, recent advances in both computation and experiment are enabling an unprecedented microscopic view of thermal transport by phonons in both bulk and nanostructured crystals, from the level of atomic bonding to mesoscopic transport in complex devices. In this topical review, we examine these techniques and the microscopic insights gained into the science and engineering of heat conduction.

  19. Prediction of ceramic stereolithography resin sensitivity from theory and measurement of diffusive photon transport

    Microsoft Academic Search

    K. C. Wu; K. F. Seefeldt; M. J. Solomon; J. W. Halloran

    2005-01-01

    A general, quantitative relationship between the photon-transport mean free path (l*) and resin sensitivity (DP) in multiple-scattering alumina\\/monomer suspensions formulated for ceramic stereolithography is presented and experimentally demonstrated. A Mie-theory-based computational method with structure factor contributions to determine l* was developed. Planar-source diffuse transmittance experiments were performed on monodisperse and bimodal polystyrene\\/water and alumina\\/monomer systems to validate this computational tool.

  20. Investigation of VOC Transport in Soil Vapors due to Wind Effects using Models and Measurement

    NASA Astrophysics Data System (ADS)

    Pennell, K. G.; Roghani, M.; Shirazi, E.; Willett, E.

    2014-12-01

    For the past several years, vapor intrusion of volatile organic compounds (VOCs) that emanate from hazardous waste sites has been gaining attention due to adverse health effects and regulatory action. Most studies of VOC vapor intrusion suggest that diffusion is the dominant contaminant transport mechanism, while advection is only considered important near contaminant entry points (i.e. building cracks). This conceptual framework is accurate when above-ground surface features do not promote air flow into (or out of) the ground surface. Recent research related to air flow in the atmospheric boundary layer (ABL) due to wind effects around buildings suggests a need for better understanding how advective transport processes can impact contaminant profiles and vapor intrusion exposure risks. In this study, a numerical model using COMSOL Multiphysics was developed to account for parameters affecting the transport of VOCs from the subsurface into buildings by considering wind effects in the ABL. Model simulations are compared to preliminary laboratory and field data to evaluate the relative importance of wind induced pressure gradients, soil permeability, soil porosity, and soil effective diffusivity on vapor intrusion entry rates. The major goal of this research is to develop an improved conceptual understanding of the vapor intrusion process so that remediation efforts can be better designed and implemented.

  1. Understanding charge transport in vacuum deposited Schottky organic solar cells with microsecond transient photocurrent measurements

    NASA Astrophysics Data System (ADS)

    Sutty, Sibi; Williams, Graeme; Aziz, Hany

    2014-10-01

    Schottky-junction organic solar cells have been a topic of intense research in recent times due to their surprisingly high performance. Some aspects of their device physics are well understood but charge transport in neat-C60 and donor-doped Schottky junction OSCs has not been studied in detail so far. In this study, charge transport in neat-C60 OSCs is examined by studying the performance of these OSCs as a function of C60 active layer thickness. Surprisingly, the fillfactor of the neat-C60 Schottky OSC does not degrade for layer thicknesses between 20 nm - 80 nm indicating that charge transport is not an issue. However, the short-circuit current decreases significantly due to a reduction in the builtin voltage. The dissociation of excitons formed in C60 aggregates is preferentially reduced. Devices with thicker C60 layers and consequently, higher C60 aggregation, were found to have greater recombination. Finally, charge mobility in C60 films with aggregates is found to be lower than charge mobility in films with little to no aggregation.

  2. Ocean Waves Measurement and Analysis, Fifth International Symposium WAVES 2005, 3rd-7th, July, 2005. Madrid, Spain Paper number: 197

    E-print Network

    Grilli, Stéphan T.

    Ocean Waves Measurement and Analysis, Fifth International Symposium WAVES 2005, 3rd-7th, July, 2005. Madrid, Spain Paper number: 197 #12;Ocean Waves Measurement and Analysis, Fifth International Symposium International Symposium WAVES 2005, 3rd-7th, July, 2005. Madrid, Spain #12;Ocean Waves Measurement and Analysis

  3. Maerz, N. H., and McKenna, S., 1999. Mobile highway inventory and measurement system. Transportation Research Record No. 1690, pp. 135-142.

    E-print Network

    Maerz, Norbert H.

    Maerz, N. H., and McKenna, S., 1999. Mobile highway inventory and measurement system. Transportation Research Record No. 1690, pp. 135-142. Surveyor® : MOBILE HIGHWAY INVENTORY AND MEASUREMENT SYSTEM@roadware.com. ABSTRACT Surveyor is a mobile highway data collection system designed to collect measurement data about

  4. Atomic Number and Electron Density Measurement Using a Conventional X-ray Tube and a CdTe Detector

    NASA Astrophysics Data System (ADS)

    Zou, Wenjuan; Nakashima, Takuya; Onishi, Yoshiaki; Koike, Akifumi; Shinomiya, Bunji; Morii, Hisashi; Neo, Yoichiro; Mimura, Hidenori; Aoki, Toru

    2008-09-01

    In order to apply the dual-energy technique to material identification, a new computed tomography scanning system was proposed using a conventional X-ray tube and a CdTe detector. This system can provide information of projection data at two distinct energy bands for scanned materials. After introducing an approximation, the measured projection data were reconstructed to obtain the distributions of the X-ray linear attenuation coefficients of the materials at two different energies. Then, the corresponding atomic number and electron density can be derived with the dual-energy X-ray computed tomography (DXCT) method adopted. By comparing the obtained results with theoretical ones, the feasibility of using this system for identifying low-Z materials was demonstrated in this study.

  5. Thermal Transport Characteristics of Human Skin Measured In Vivo Using Ultrathin Conformal Arrays of Thermal Sensors and Actuators

    PubMed Central

    Webb, R. Chad; Pielak, Rafal M.; Bastien, Philippe; Ayers, Joshua; Niittynen, Juha; Kurniawan, Jonas; Manco, Megan; Lin, Athena; Cho, Nam Heon; Malyrchuk, Viktor; Balooch, Guive; Rogers, John A.

    2015-01-01

    Measurements of the thermal transport properties of the skin can reveal changes in physical and chemical states of relevance to dermatological health, skin structure and activity, thermoregulation and other aspects of human physiology. Existing methods for in vivo evaluations demand complex systems for laser heating and infrared thermography, or they require rigid, invasive probes; neither can apply to arbitrary regions of the body, offers modes for rapid spatial mapping, or enables continuous monitoring outside of laboratory settings. Here we describe human clinical studies using mechanically soft arrays of thermal actuators and sensors that laminate onto the skin to provide rapid, quantitative in vivo determination of both the thermal conductivity and thermal diffusivity, in a completely non-invasive manner. Comprehensive analysis of measurements on six different body locations of each of twenty-five human subjects reveal systematic variations and directional anisotropies in the characteristics, with correlations to the thicknesses of the epidermis (EP) and stratum corneum (SC) determined by optical coherence tomography, and to the water content assessed by electrical impedance based measurements. Multivariate statistical analysis establishes four distinct locations across the body that exhibit different physical properties: heel, cheek, palm, and wrist/volar forearm/dorsal forearm. The data also demonstrate that thermal transport correlates negatively with SC and EP thickness and positively with water content, with a strength of correlation that varies from region to region, e.g., stronger in the palmar than in the follicular regions. PMID:25658947

  6. Wind Tunnel Measured Effects on a Twin-Engine Short-Haul Transport Caused by Simulated Ice Accretions

    NASA Technical Reports Server (NTRS)

    Reehorst, Andrew; Potapczuk, Mark; Ratvasky, Thomas; Laflin, Brenda Gile

    1996-01-01

    A series of wind tunnel tests were conducted to assess the effects of leading edge ice contamination upon the performance of a short-haul transport. The wind tunnel test was conducted in the NASA Langley 14 by 22 foot facility. The test article was a 1/8 scale twin-engine short-haul jet transport model. Two separate leading edge ice contamination configurations were tested in addition to the uncontaminated baseline configuration. Several aircraft configurations were examined including various flap and slat deflections, with and without landing gear. Data gathered included force measurements via an internal six-component force balance, pressure measurements through 700 electronically scanned wing pressure ports, and wing surface flow visualization measurements. The artificial ice contamination caused significant performance degradation and caused visible changes demonstrated by the flow visualization. The data presented here is just a portion of the data gathered. A more complete data report is planned for publication as a NASA Technical Memorandum and data supplement.

  7. Thermal transport characteristics of human skin measured in vivo using ultrathin conformal arrays of thermal sensors and actuators.

    PubMed

    Webb, R Chad; Pielak, Rafal M; Bastien, Philippe; Ayers, Joshua; Niittynen, Juha; Kurniawan, Jonas; Manco, Megan; Lin, Athena; Cho, Nam Heon; Malyrchuk, Viktor; Balooch, Guive; Rogers, John A

    2015-01-01

    Measurements of the thermal transport properties of the skin can reveal changes in physical and chemical states of relevance to dermatological health, skin structure and activity, thermoregulation and other aspects of human physiology. Existing methods for in vivo evaluations demand complex systems for laser heating and infrared thermography, or they require rigid, invasive probes; neither can apply to arbitrary regions of the body, offers modes for rapid spatial mapping, or enables continuous monitoring outside of laboratory settings. Here we describe human clinical studies using mechanically soft arrays of thermal actuators and sensors that laminate onto the skin to provide rapid, quantitative in vivo determination of both the thermal conductivity and thermal diffusivity, in a completely non-invasive manner. Comprehensive analysis of measurements on six different body locations of each of twenty-five human subjects reveal systematic variations and directional anisotropies in the characteristics, with correlations to the thicknesses of the epidermis (EP) and stratum corneum (SC) determined by optical coherence tomography, and to the water content assessed by electrical impedance based measurements. Multivariate statistical analysis establishes four distinct locations across the body that exhibit different physical properties: heel, cheek, palm, and wrist/volar forearm/dorsal forearm. The data also demonstrate that thermal transport correlates negatively with SC and EP thickness and positively with water content, with a strength of correlation that varies from region to region, e.g., stronger in the palmar than in the follicular regions. PMID:25658947

  8. Three-dimensional shape measurement system applied to superficial inspection of non-metallic pipes for the hydrocarbons transport

    NASA Astrophysics Data System (ADS)

    Arciniegas, Javier R.; González, Andrés. L.; Quintero, L. A.; Contreras, Carlos R.; Meneses, Jaime E.

    2014-05-01

    Three-dimensional shape measurement is a subject that consistently produces high scientific interest and provides information for medical, industrial and investigative applications, among others. In this paper, it is proposed to implement a three-dimensional (3D) reconstruction system for applications in superficial inspection of non-metallic pipes for the hydrocarbons transport. The system is formed by a CCD camera, a video-projector and a laptop and it is based on fringe projection technique. System functionality is evidenced by evaluating the quality of three-dimensional reconstructions obtained, which allow observing the failures and defects on the study object surface.

  9. Note: Adhesive stamp electrodes using spider silk masks for electronic transport measurements of supra-micron sized samples

    NASA Astrophysics Data System (ADS)

    Steven, E.; Jobiliong, E.; Eugenio, P. M.; Brooks, J. S.

    2012-04-01

    A procedure for fabricating adhesive stamp electrodes based on gold coated adhesive tape used to measure electronic transport properties of supra-micron samples in the lateral range 10-100 ?m and thickness >1 ?m is described. The electrodes can be patterned with a ˜4 ?m separation by metal deposition through a mask using Nephila clavipes spider dragline silk fibers. Ohmic contact is made by adhesive lamination of a sample onto the patterned electrodes. The performance of the electrodes with temperature and magnetic field is demonstrated for the quasi-one-dimensional organic conductor (TMTSF)2PF6 and single crystal graphite, respectively.

  10. Low-Speed Stability-and-Control and Ground-Effects Measurements on the Industry Reference High Speed Civil Transport

    NASA Technical Reports Server (NTRS)

    Kemmerly, Guy T.; Campbell, Bryan A.; Banks, Daniel W.; Yaros, Steven F.

    1999-01-01

    As a part of a national effort to develop an economically feasible High Speed Civil Transport (HSCT), a single configuration has been accepted as the testing baseline by the organizations working in the High Speed Research (HSR) program. The configuration is based on a design developed by the Boeing Company and is referred to as the Reference H (Ref H). The data contained in this report are low-speed stability-and-control and ground-effect measurements obtained on a 0.06 scale model of the Ref H in a subsonic tunnel.

  11. Beam measurements on the H- source and Low Energy Beam Transport system for the Spallation Neutron Source

    SciTech Connect

    Thomae, R.; Gough, R.; Keller, R.; Leung, K.N.; Schenkel, T.; Aleksandrov, A.; Stockli, M.; Welton, R.

    2001-09-01

    The ion source and Low Energy Beam Transport section of the front-end systems presently being built by Berkeley Lab are required to provide 50 mA of H - beam current at 6% duty factor (1 ms pulses at 60 Hz) with a normalized rms emittance of less than 0.20 p-mm-mrad. Experimental results, including emittance, chopping, and steering measurements, on the performance of the ion source and LEBT system operated at the demanded beam parameters will be discussed.

  12. Note: adhesive stamp electrodes using spider silk masks for electronic transport measurements of supra-micron sized samples.

    PubMed

    Steven, E; Jobiliong, E; Eugenio, P M; Brooks, J S

    2012-04-01

    A procedure for fabricating adhesive stamp electrodes based on gold coated adhesive tape used to measure electronic transport properties of supra-micron samples in the lateral range 10-100 ?m and thickness >1 ?m is described. The electrodes can be patterned with a ~4 ?m separation by metal deposition through a mask using Nephila clavipes spider dragline silk fibers. Ohmic contact is made by adhesive lamination of a sample onto the patterned electrodes. The performance of the electrodes with temperature and magnetic field is demonstrated for the quasi-one-dimensional organic conductor (TMTSF)(2)PF(6) and single crystal graphite, respectively. PMID:22559592

  13. Calorimetric AC loss measurement of MgB2 superconducting tape in an alternating transport current and direct magnetic field

    NASA Astrophysics Data System (ADS)

    See, K. W.; Xu, X.; Horvat, J.; Cook, C. D.; Dou, S. X.

    2012-11-01

    Applications of MgB2 superconductors in electrical engineering have been widely reported, and various studies have been made to define their alternating current (AC) losses. However, studies on the transport losses with an applied transverse DC magnetic field have not been conducted, even though this is one of the favored conditions in applications of practical MgB2 tapes. Methods and techniques used to characterize and measure these losses have so far been grouped into ‘electrical’ and ‘calorimetric’ approaches with external conditions set to resemble the application conditions. In this paper, we present a new approach to mounting the sample and employ the calorimetric method to accurately determine the losses in the concurrent application of AC transport current and DC magnetic fields that are likely to be experienced in practical devices such as generators and motors. This technique provides great simplification compared to the pickup coil and lock-in amplifier methods and is applied to a long length (˜10 cm) superconducting tape. The AC loss data at 20 and 30 K will be presented in an applied transport current of 50 Hz under external DC magnetic fields. The results are found to be higher than the theoretical predictions because of the metallic fraction of the tape that contributes quite significantly to the total losses. The data, however, will allow minimization of losses in practical MgB2 coils and will be used in the verification of numerical coil models.

  14. Impurity transport measurements in beam heated low-confinement mode discharges in the National Spherical Torus Experiment

    NASA Astrophysics Data System (ADS)

    Stutman, D.; Finkenthal, M.; Bell, R. E.; Kaye, S. M.; LeBlanc, B. P.; Menard, J. E.; Synakowski, E. J.; Darrow, D. S.; Soukhanovskii, V.; Bourdelle, C.

    2003-11-01

    Impurity injection experiments were performed in the National Spherical Torus Experiment [NSTX, M. Ono et al., Nucl. Fusion 40, 557 (2000)] for a first assessment of low-Z impurity transport in a low field, low-aspect ratio device. Short neon puffs were injected in beam heated, co-rotating L-mode (low confinement) discharges and the radial penetration of the successive neon charge states has been monitored with arrays of filtered ultrasoft x-ray diodes. Time-dependent modeling of the neon emissivity in several spectral bands indicates a core diffusion coefficient in the neoclassical range (<1 m2/s) in these strongly rotating plasmas, consistent with the low thermal ion transport inferred from the power balance analysis. By contrast, due to the large Larmor radii in NSTX turbulent diffusion would reach tens of m2/s if tokamak-like instability growth rates were assumed. The much lower experimental diffusivity then suggests that turbulent ion transport must be largely suppressed in the NSTX core. It is not yet clear in what measure this is due to the large E×B flow shear characteristic of beam heated NSTX discharges, or to the long wavelength instability growth rates being intrinsically low in the NSTX core, as recently predicted.

  15. Metal-molecule contacts and charge transport across monomolecular layers: measurement and theory.

    PubMed

    Kushmerick, J G; Holt, D B; Yang, J C; Naciri, J; Moore, M H; Shashidhar, R

    2002-08-19

    Charge transport studies across molecular length scales under symmetric and asymmetric metal-molecule contact conditions using a simple crossed-wire tunnel junction technique are presented. It is demonstrated that oligo(phenylene ethynylene), a conjugated organic molecule, acts like a molecular wire under symmetric contact conditions, but exhibits characteristics of a molecular diode when the connections are asymmetric. To understand this behavior, we have calculated current-voltage (I-V) characteristics using extended Huckel theory coupled with a Green's function approach. The experimentally observed I-V characteristics are in excellent qualitative agreement with the theory. PMID:12190491

  16. In situ optical measurement of charge transport dynamics in organic photovoltaics.

    PubMed

    Chow, Philip C Y; Bayliss, Sam L; Lakhwani, Girish; Greenham, Neil C; Friend, Richard H

    2015-02-11

    We present a novel experimental approach which allows extraction of both spatial and temporal information on charge dynamics in organic solar cells. Using the wavelength dependence of the photonic structure in these devices, we monitor the change in spatial overlap between the photogenerated hole distribution and the optical probe profile as a function of time. In a model system we find evidence for a buildup of the photogenerated hole population close to the hole-extracting electrode on a nanosecond time scale and show that this can limit charge transport through space-charge effects under operating conditions. PMID:25585168

  17. Intracellular Drug Concentrations and Transporters: Measurement, Modeling, and Implications for the Liver

    PubMed Central

    Chu, X; Korzekwa, K; Elsby, R; Fenner, K; Galetin, A; Lai, Y; Matsson, P; Moss, A; Nagar, S; Rosania, GR; Bai, JPF; Polli, JW; Sugiyama, Y; Brouwer, KLR

    2013-01-01

    Intracellular concentrations of drugs and metabolites are often important determinants of efficacy, toxicity, and drug interactions. Hepatic drug distribution can be affected by many factors, including physicochemical properties, uptake/efflux transporters, protein binding, organelle sequestration, and metabolism. This white paper highlights determinants of hepatocyte drug/metabolite concentrations and provides an update on model systems, methods, and modeling/simulation approaches used to quantitatively assess hepatocellular concentrations of molecules. The critical scientific gaps and future research directions in this field are discussed. PMID:23588320

  18. The use of strontium-87/strontium-86 ratios to measure atmospheric transport into forested watersheds.

    PubMed

    Graustein, W C; Armstrong, R L

    1983-01-21

    Strontium-87/strontium-86 ratios indicate the sources of strontium in samples of natural waters, vegetation, and soil material taken from watersheds in the Sangre de Cristo Mountains of New Mexico. More than 75 percent of the strontium in the vegetation is ultimately derived from atmospheric transport and less than 25 percent from the weathering of the underlying rock. Much of the airborne strontium enters the watersheds by impacting on coniferous foliage, but deciduous foliage apparently traps little, if any, strontium-bearing aerosol. The strontium and presumably other nutrients are continuously recycled in a nearly closed system consisting of upper soil horizons, forest litter, and the standing crop of vegetation. PMID:17798277

  19. Assimilation of IASI satellite CO fields into a global chemistry transport model for validation against aircraft measurements

    NASA Astrophysics Data System (ADS)

    Klonecki, A.; Pommier, M.; Clerbaux, C.; Ancellet, G.; Cammas, J.-P.; Coheur, P.-F.; Cozic, A.; Diskin, G. S.; Hadji-Lazaro, J.; Hauglustaine, D. A.; Hurtmans, D.; Khattatov, B.; Lamarque, J.-F.; Law, K. S.; Nedelec, P.; Paris, J.-D.; Podolske, J. R.; Prunet, P.; Schlager, H.; Szopa, S.; Turquety, S.

    2012-05-01

    This work evaluates the IASI CO product against independent in-situ aircraft data from the MOZAIC program and the POLARCAT aircraft campaign. The validation is carried out by analysing the impact of assimilation of eight months of IASI CO columns retrieved for the period of May to December 2008 into the global chemistry transport model LMDz-INCA. A modelling system based on a sub-optimal Kalman filter was developed and a specific treatment that takes into account the representativeness of observations at the scale of the model grid is applied to the IASI CO columns and associated errors before their assimilation in the model. Comparisons of the assimilated CO profiles with in situ CO measurements indicate that the assimilation leads to a considerable improvement of the model simulations in the middle troposphere as compared with a control run with no assimilation. Model biases in the simulation of background values are reduced and improvement in the simulation of very high concentrations is observed. The improvement is due to the transport by the model of the information present in the IASI CO retrievals. Our analysis also shows the impact of assimilation of CO on the representation of transport into the Arctic region during the POLARCAT summer campaign. A considerable increase in CO mixing ratios over the Asian source region was observed when assimilation was used leading to much higher values of CO during the cross-pole transport episode. These higher values are in good agreement with data from the POLARCAT flights that sampled this plume.

  20. Individual Differences in Non-verbal Number Discrimination Correlate with Event-related Potentials and Measures of Probabilistic Reasoning

    PubMed Central

    Paulsen, David J.; Woldorff, Marty G.; Brannon, Elizabeth M.

    2010-01-01

    The current study investigated the neural activity patterns associated with numerical sensitivity in adults. Event-related potentials (ERPs) were recorded while adults observed sequentially presented display arrays (S1 and S2) of non-symbolic numerical stimuli (dots) and made same/different judgments of these stimuli by pressing a button only when numerosities were the same (target trials). The main goals were to contrast the effects of numerical distance (close, medium, and far) and change direction (increasing, decreasing) between S1 and S2, both in terms of behavior and brain activity, and to examine the influence of individual differences in numeracy on the effects of these manipulations. Neural effects of distance were found to be significant between 360–600 ms after the onset of S2 (greater negativity-wave activity for closer numerical distances), while direction effects were found between 320–440ms (greater negativity for decreasing direction). ERP change-direction effects did not interact with numerical distance, suggesting that the two types of information are processed independently. Importantly, subjects’ behavioral Weber fractions (w) for the same/different discrimination task correlated with distance-related ERP-activity amplitudes. Moreover, w also correlated with a separate objective measure of mathematical ability. Results thus draw a clear link between brain and behavior measures of number discrimination, while also providing support for the relationship between non-verbal magnitude discrimination and symbolic numerical processing. PMID:20817003

  1. Probing Energy Levels of Large Array Quantum Dot Superlattice by Electronic Transport Measurement

    NASA Astrophysics Data System (ADS)

    Bisri, S. Z.; Degoli, E.; Spallanzani, N.; Krishnan, G.; Kooi, B.; Ghica, C.; Yarema, M.; Protesescu, L.; Heiss, W.; Kovalenko, M.; Pulci, O.; Ossicini, S.; Iwasa, Y.; Loi, M. A.

    2015-03-01

    Colloidal quantum dot superlattice (CQDS) emerges as new type of hybrid solids allowing easy fabrication of devices that exploits the quantum confinement properties of individual QD. This materials displays peculiar characters, making investigation of their transport properties nontrivial. Besides the bandgap variations, 0D nature of QD lead to the formation of discrete energy subbands. These subbands are crucial for multiple exciton generation (for efficient solar cell), thermoelectric material and multistate transistor. Full understanding of the CQDS energy level structure is vital to use them in complex devices. Here we show a powerful method to determine the CQDS electronic energy levels from their intrinsic charge transport characteristics. Via the use of ambipolar transistors with CQDS as active materials and gated using highly capacitive ionic liquid gating, Fermi energy can be largely tuned. It can access energy levels beyond QD's HOMO & LUMO. Ability to probe not only the bandgap, but also the discrete energy level from large assembly of QD at room temperature suggests the formation of energy minibands in this system.

  2. Combined aerosol in-situ measurements during the SALTRACE field experiment for the investigation of Saharan mineral dust microphysical and CCN properties and their spatial-temporal evolution during trans-Atlantic long-range transport

    NASA Astrophysics Data System (ADS)

    Walser, Adrian; Dollner, Maximilian; Sauer, Daniel; Weinzierl, Bernadett

    2015-04-01

    The Saharan Aerosol Long-range Transport and Aerosol-Cloud-Interaction Experiment (SALTRACE) was a field experiment conducted in June/July 2013, which aimed to investigate the transport and modification of Saharan mineral dust from the Sahara across the Atlantic Ocean to the Caribbean. In addition to ground-based measurements and satellite remote sensing, the DLR Falcon research aircraft was equipped with a number of aerosol in-situ instruments to gain direct information on the properties of airborne aerosol such as size distributions, microphysical, optical and cloud-condensation nuclei (CCN) properties. For the first time, several outbreaks of Saharan dust were probed with the same airborne instrumentation on both sides of the Atlantic. During transport, various processes may take place that modify the aerosol composition. Dry and wet deposition lead to a size-dependent aerosol removal. In case of wet deposition, the removal additionally depends on the particle's ability to act as CCN. Processes in the aqueous phase in subsequently re-evaporating cloud droplets can further alter microphysical and CCN properties of re-released particles. All resulting changes in the size distribution and particle properties impact the radiative feedback and CCN activity of the aged aerosol. This study aims to use combined airborne in-situ measurements to retrieve and compare vertically resolved aerosol size distributions, microphysical and CCN properties for both, short-range transported Saharan dust in the Cape Verde region and long-range transported dust in the Caribbean. We use this data to investigate the influence of long-range transport and associated processes on those properties. We will present vertical profiles of size-resolved aerosol concentrations and volatile fractions as well as CCN activated fractions and draw conclusions for aerosol mixing state, CCN activation diameters and particle hygroscopicities. We will discuss differences in vertical profiles and variabilities between the Cape Verde region and the Caribbean and possible reasons.

  3. Assessment of Quality Assurance Measures for Radioactive Material Transport Packages not Requiring Competent Authority Design Approval - 13282

    SciTech Connect

    Komann, Steffen; Groeke, Carsten; Droste, Bernhard [BAM Federal Institute for Materials Research and Testing, Unter den Eichen 44-46, 12203 Berlin (Germany)] [BAM Federal Institute for Materials Research and Testing, Unter den Eichen 44-46, 12203 Berlin (Germany)

    2013-07-01

    The majority of transports of radioactive materials are carried out in packages which don't need a package design approval by a competent authority. Low-active radioactive materials are transported in such packages e.g. in the medical and pharmaceutical industry and in the nuclear industry as well. Decommissioning of NPP's leads to a strong demand for packages to transport low and middle active radioactive waste. According to IAEA regulations the 'non-competent authority approved package types' are the Excepted Packages and the Industrial Packages of Type IP-1, IP-2 and IP-3 and packages of Type A. For these types of packages an assessment by the competent authority is required for the quality assurance measures for the design, manufacture, testing, documentation, use, maintenance and inspection (IAEA SSR 6, Chap. 306). In general a compliance audit of the manufacturer of the packaging is required during this assessment procedure. Their regulatory level in the IAEA regulations is not comparable with the 'regulatory density' for packages requiring competent authority package design approval. Practices in different countries lead to different approaches within the assessment of the quality assurance measures in the management system as well as in the quality assurance program of a special package design. To use the package or packaging in a safe manner and in compliance with the regulations a management system for each phase of the life of the package or packaging is necessary. The relevant IAEA-SSR6 chap. 801 requires documentary verification by the consignor concerning package compliance with the requirements. (authors)

  4. Measuring Molecular Motor Forces In Vivo: Implications for Tug-of-War Models of Bidirectional Transport

    E-print Network

    Texas at Austin. University of

    Measuring Molecular Motor Forces In Vivo: Implications for Tug-of-War Models of Bidirectional ATP hydrolysis to generate force and haul cargoes along cytoskeletal filaments. Thus, measuring the force motors generate amounts to directly probing their function. We report on optical trapping

  5. Measurement of the direct particle transport through stochastic media using neutron resonance transmission analysis

    NASA Astrophysics Data System (ADS)

    Becker, Bjorn; Kopecky, Stefan; Harada, Hideo; Schillebeeckx, Peter

    2014-04-01

    A measurement of the uncollided neutron flux passing through a sample containing a stochastic mixture of tungsten and sulfur grains has been performed using neutron resonance transmission analysis in the 3-200eV energy region. The impact of the heterogeneous characteristic of the sample is shown, based on a comparison of the measurement with a calculated transmission spectrum of a homogeneous sample, which was verified by a measurement with a homogeneous metallic disc. By using a single strong resonance of tungsten, the particle self-shielding factor between 0.2-0.9 was directly measured. The experimental data have been compared with model calculations using the Markovian Levermore-Pomraning model. The measured transmission has been used to determine the effective characteristic chord length and volume fraction of the tungsten grains within the sample.

  6. Measuring Ligand-Dependent Transport in Nanopatterned PbS Colloidal Quantum Dot Arrays Using Charge Sensing.

    PubMed

    Ray, Nirat; Staley, Neal E; Grinolds, Darcy D W; Bawendi, Moungi G; Kastner, Marc A

    2015-07-01

    Colloidal quantum dot arrays with long organic ligands have better packing order than those with short ligands but are highly resistive, making low-bias conductance measurements impossible with conventional two-probe techniques. We use an integrated charge sensor to study transport in weakly coupled arrays in the low-bias regime, and we nanopattern the arrays to minimize packing disorder. We present the temperature and field dependence of the resistance for nanopatterned oleic-acid and n-butylamine-capped PbS arrays, measuring resistances as high as 10(18) ?. We find that the conduction mechanism changes from nearest neighbor hopping in oleic-acid-capped PbS dots to Mott's variable range hopping in n-butylamine capped PbS dots. Our results can be understood in terms of a change in the interdot coupling strength or a change in density of trap states and highlight the importance of the capping ligand on charge transport through colloidal quantum dot arrays. PMID:26044997

  7. Four-dimensional data assimilation experiments with International Consortium for Atmospheric Research on Transport and Transformation ozone measurements

    NASA Astrophysics Data System (ADS)

    Chai, Tianfeng; Carmichael, Gregory R.; Tang, Youhua; Sandu, Adrian; Hardesty, Michael; Pilewskie, Peter; Whitlow, Sallie; Browell, Edward V.; Avery, Melody A.; NéDéLec, Philippe; Merrill, John T.; Thompson, Anne M.; Williams, Eric

    2007-06-01

    Ozone measurements by various platforms during the International Consortium for Atmospheric Research on Transport and Transformation (ICARTT) operations in the summer of 2004 are assimilated into the STEM regional chemical transport model (CTM). Under the four-dimensional variational data assimilation (4D-Var) framework, the model forecast (background) error covariance matrix is constructed using both the so-called NMC (National Meteorological Center, now National Centers for Environmental Prediction) method and the observational (Hollingworth-Lönnberg) method. The inversion of the covariance matrix is implemented using truncated singular value decomposition (TSVD) approach. The TSVD approach is numerically stable even with severely ill conditioned vertical correlation covariance matrix and large horizontal correlation distances. Ozone observations by different platforms (aircraft, surface, and ozonesondes) are first assimilated separately. The impacts of the various measurements are evaluated on their ability to improve the predictions, defined as the information content of the observations under the current framework. In the end, all observations are assimilated into the CTM. The final analysis matches well with observations from all platforms. Assessed with all the observations throughout the boundary layer and midtroposphere, the model bias is reduced from 11.3 ppbv for the base case to -1.5 ppbv. A reduction of 10.3 ppbv in root mean square error is also seen. In addition, the potential of improving air quality forecasts by chemical data assimilation is demonstrated. The effect of assimilating ozone observations on model predictions of other species is also shown.

  8. Temporal and spatial effects of ablation plume on number density distribution of droplets in an aerosol measured by laser-induced breakdown

    SciTech Connect

    Yashiro, H.; Kakehata, M. [Electronics and Photonics Research Institute (ESPRIT), National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Umezono, Tsukuba, Ibaraki 305-8568 (Japan)

    2013-05-07

    We proposed and experimentally demonstrated a novel method of evaluating the number density of droplets in an aerosol by laser-induced breakdown. The number density of droplets is evaluated from the volume in which the laser intensity exceeds the breakdown threshold intensity for droplets, and the number of droplets in this volume, which is evaluated by the experimentally observed breakdown probability. This measurement method requires a large number of laser shots for not only precise measurement but also highly temporally and spatially resolved density distribution in aerosol. Laser ablation plumes ejected from liquid droplets generated by breakdown disturb the density around the measurement points. Therefore, the recovery time of the density determines the maximum repetition rate of the probe laser irradiating a fixed point. The expansion range of the ablation plume determines the minimum distance at which the measurement points are unaffected by a neighboring breakdown when multiple laser beams are simultaneously irradiated. These laser irradiation procedures enable the measurement of the number density distribution of droplets in an aerosol at a large number of points within a short measurement time.

  9. Prediction of ceramic stereolithography resin sensitivity from theory and measurement of diffusive photon transport

    NASA Astrophysics Data System (ADS)

    Wu, K. C.; Seefeldt, K. F.; Solomon, M. J.; Halloran, J. W.

    2005-07-01

    A general, quantitative relationship between the photon-transport mean free path (l*) and resin sensitivity (DP) in multiple-scattering alumina/monomer suspensions formulated for ceramic stereolithography is presented and experimentally demonstrated. A Mie-theory-based computational method with structure factor contributions to determine l* was developed. Planar-source diffuse transmittance experiments were performed on monodisperse and bimodal polystyrene/water and alumina/monomer systems to validate this computational tool. The experimental data support the application of this l* calculation method to concentrated suspensions composed of nonaggregating particles of moderately aspherical shape and log-normal size distribution. The values of DP are shown to be approximately five times that of l* in the tested ceramic stereolithography suspensions.

  10. Transport measurements of negative refractive behavior in ballistic graphene hetero junctions

    NASA Astrophysics Data System (ADS)

    Lee, Gil-Ho; Park, Geon-Hyoung; Kim, Minsoo; Lee, Jae Hyeong; Lee, Hu-Jong

    2015-03-01

    We investigated the electronic current refraction at p-n junctions (PNJs) in ballistic monolayer graphene. Given a peculiar band structure of the graphene, the transmission of electrons through a PNJ is predicted to be similar to the optical refraction at the boundary of metamaterials with negative refractive index. In consequence, electrons waves injected at a point in one side of a junction can be refocused into a single point in the other side of the junction, which demonstrates Veselago lensing for the electrons. By adopting high-yield dry-transfer technique, we fabricated fully ballistic graphene devices encapsulated by hexagonal boron nitrides with a local top gate. We will present the signatures of negative refractive transport behavior of electrons in PNJs and also discuss about the electronic current focusing in p-n-p heterojunctions in terms of Veselago lensing.

  11. Low-altitude wind measurements from wide-body jet transports

    NASA Technical Reports Server (NTRS)

    Dunham, R. E., Jr.

    1982-01-01

    For a 2-week period in the spring of 1977, data were collected onboard wide-body jet transports for the determination of winds and wind shear during landings and take-offs. The data represent about 640 take-offs or landings at 14 airports in Europe and the United States. Analysis of the wind-shear data indicates that shears of a given value are equally likely to occur at any altitude in the lower 1400-ft section of the atmosphere. Analysis of the data indicates that low shears (plus or minus .033 knot/per ft) have a 67-percent chance of occurrence during a landing or take-off, while higher values (plus or minus 0.15 knot/per ft) have a 0.5-percent chance of occurrence. A determination of the duration of a given shear was not made.

  12. Prediction of ceramic stereolithography resin sensitivity from theory and measurement of diffusive photon transport

    SciTech Connect

    Wu, K.C.; Seefeldt, K.F.; Solomon, M.J.; Halloran, J.W. [Department of Materials Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109 (United States); Department of Chemical Engineering, University of Michigan, Ann Arbor, Michigan 48109 (United States); Department of Materials Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109 (United States)

    2005-07-15

    A general, quantitative relationship between the photon-transport mean free path (l*) and resin sensitivity (D{sub P}) in multiple-scattering alumina/monomer suspensions formulated for ceramic stereolithography is presented and experimentally demonstrated. A Mie-theory-based computational method with structure factor contributions to determine l* was developed. Planar-source diffuse transmittance experiments were performed on monodisperse and bimodal polystyrene/water and alumina/monomer systems to validate this computational tool. The experimental data support the application of this l* calculation method to concentrated suspensions composed of nonaggregating particles of moderately aspherical shape and log-normal size distribution. The values of D{sub P} are shown to be approximately five times that of l* in the tested ceramic stereolithography suspensions.

  13. Thermal transport in CO2 laser irradiated fused silica: In situ measurements and analysis

    Microsoft Academic Search

    Steven T. Yang; Manyalibo J. Matthews; Selim Elhadj; Vaughn G. Draggoo; Scott E. Bisson

    2009-01-01

    In situ spatial and temporal temperature measurements of pristine fused silica surfaces heated with a 10.6 ?mCO2 laser were obtained using an infrared radiation thermometer based on a mercury cadmium telluride camera. Laser spot sizes ranged from 250 to 1000 ?m diameter with peak axial irradiance levels of 0.13–16 kW\\/cm2. For temperatures below 2800 K, the measured steady-state surface temperature

  14. Thermal transport in CO2 laser irradiated fused silica: In situ measurements and analysis

    Microsoft Academic Search

    Steven T. Yang; Manyalibo J. Matthews; Selim Elhadj; Vaughn G. Draggoo; Scott E. Bisson

    2009-01-01

    In situ spatial and temporal temperature measurements of pristine fused silica surfaces heated with a 10.6 mum CO2 laser were obtained using an infrared radiation thermometer based on a mercury cadmium telluride camera. Laser spot sizes ranged from 250 to 1000 mum diameter with peak axial irradiance levels of 0.13-16 kW\\/cm2. For temperatures below 2800 K, the measured steady-state surface

  15. Measurements of the effect of a magnetic field on the transport of linear momentum in nitrogen

    E-print Network

    Larchez, Mark Edward

    1968-01-01

    thermocouple gauge that, hac been calibrated against a YicLeod gauge. The lead weighting was increased and redistributed anc the microscope mountec directly on the apparatus in order to reduce problems from ex- ternal vibrations. Additional magnets were... is measured by observing fiducial marks on the quartz support rod with a 50x micrometer micro- scope having moveable crosshairs. In orner to obtain accurate values it is necessary to measure the change in ceflection as the magnetic field is switchec...

  16. Effects of unstirred layers or transport number discontinuities on the transient and steady-state current-voltage relationships of membranes.

    PubMed

    Macdonald, R C

    1976-10-01

    The effects of current-induced electrolyte accumulation and depletion on the electrical properties of a two-layered membrane system have been examined. The membrane consisted of a charged, ion permselective layer and an uncharged, non-selective layer. The model was designed to reveal the properties of membranes possessing long pores with ionic charges at one end or of ion-selective membranes bounded by highly unstirred aqueous layers. Electrolyte concentration profiles in the inert layer and their time-dependent changes were obtained from solutions of the diffusion equation under the condition of constant current. The profiles were then used to calculate the voltage developed across the membrane at various times after the current is switched on. The theoretical results are presented in the form of i-V curves with reduced coordinates that can be used to obtain time-current-voltage relationships for membranes of the type considered having any thickness of the non-selective layer and bathed in any concentration of any 1:1 electrolyte. Experimental results on a model composite membrane were in good agreement with calculations that assume that ion transport occurs only under the influence of electrical potential and concentration gradients, suggesting that in such systems, the combined effects of convection, osmosis, electro-osmosis, and concentration-dependence of diffusion coefficients, activity coefficients, and transference numbers are small. Voltage fluctuations in the form of periodic spikes were observed experimentally at the limiting current density (the current density at which the electrolyte concentration at one surface of the selective layer goes to 0). These phenomena were not seen when the current was in the direction leading to accumulation of electrolyte in the non-selective (unstirred) layer. Such composite membranes can exhibit S-shaped and N-shaped i-V curves under ramp-voltage and ramp-current clamps, respectively. PMID:971431

  17. Removing Traffic Emissions from CO2 Time Series Measured at a Tall Tower Using on-Road Measurements and WRF-Stilt Transport Modeling

    NASA Astrophysics Data System (ADS)

    Schmidt, A.; Rella, C.; Goeckede, M.; Hanson, C. V.; Yang, Z.; Law, B. E.

    2014-12-01

    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 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 from 9.8 to 12 ppm, depending on the height above the surface, during summer 2012.

  18. Heat Transfer and Pressure Drop Measurement for Square Channels with V-shape Ribs at High Reynolds Numbers

    E-print Network

    Alkhamis, Nawaf Yahya

    2010-10-12

    enhancement decreases when the Reynolds number increases. The friction factor is found to be independent of The Reynolds number. The thermal performance decreases when the Reynolds number increases. Correlations for the Nusselt number and the friction... scholarship to study at Texas A&M University. v NOMENCLATURE C p Specific Heat D Hydraulic Diameter e Rib Height f Fanning Friction Factor F Thermal Performance f 0 Friction Factor Corresponding to Smooth...

  19. Triaxial creep measurements on rock salt from the Jennings dome, Louisiana, borehole LA-1, core {number_sign}8

    SciTech Connect

    Wawersik, W.R.; Zimmerer, D.J.

    1994-05-01

    Tejas Power Company requested that facilities in the Rock Mechanics Laboratory at Sandia National Laboratories be used to assess the time-dependent properties of rock salt from the Jennings dome in Acadia Parish, Louisiana. Nominally 2.5-inch diameter slat core from borehole LA-1, core 8 (depth 3924.8 to 3837.8 ft; 1196.8--1197.1 m) was provided to accomplish two tasks: (1) Using the smallest possible number of experiments, evaluate the tendency of Jennings salt to undergo time-dependent deformation (creep) under constant applied stresses, and compare the creep of Jennings salt with creep data for rock salt from other locations. (2) Assess the applicability of published laboratory-derived creep properties for rock salt from several bedded and domal sites in finite element analyses concerning the design of new gas storage caverns in the Jennings dome. The characterization of Jennings salt followed the same strategy that was applied in earlier laboratory experiments on core from the Moss Bluff dome near Houston, Texas. This report summarizes the relevant details of five creep experiments on a sample from depth 3927.5 ft, the results obtained, and how these results compared with laboratory creep measurements gathered on rock salt from other locations including the West Hackberry, Bryan Mound and Moss Bluff domes. The report also considers the estimates of specific creep parameters commonly used in numerical engineering design analyses.

  20. Measurements of Free-Space Oscillating Pressures Near Propellers at Flight Mach Numbers to 0.72

    NASA Technical Reports Server (NTRS)

    Kurbjun, Max C; Vogeley, Arthur W

    1958-01-01

    In the course of a short flight program initiated to check the theory of Garrick and Watkins (NACA rep. 1198), a series of measurements at three stations were made of the oscillating pressures near a tapered-blade plan-form propeller and rectangular-blade plan form propeller at flight Mach numbers up to 0.72. In contradiction to the results for the propeller studied in NACA rep. 1198, the oscillating pressures in the plane ahead of the propeller were found to be higher than those immediately behind the propeller. Factors such as variation in torque and thrust distribution, since the blades of the present investigation were operating above their design forward speed, may account for this contradiction. The effect of blade plan form shows that a tapered-blade plan-form propeller will produce lower sound-pressure levels than a rectangular-blade plan-form propeller for the low blade-passage harmonics (the frequencies where structural considerations are important) and produce higher sound-pressure levels for the higher blade-passage harmonics (frequencies where passenger comfort is important).

  1. Resolving the Impact of Biological Processes on DNAPL Transport in Unsaturated Porous Media Through Nuclear Magnetic Resonance Relaxation Time Measurements

    NASA Astrophysics Data System (ADS)

    Hertzog, R. C.; Geesey, G.; White, T.; Oram, L.; Seymour, J.; Codd, S.; Straley, C.; Bryar, T.

    2003-12-01

    This research leads to a better understanding of how physical and biological properties of porous media influence water and dense non-aqueous phase liquid (DNAPL) distributions under saturated and unsaturated conditions. Knowing how environmental properties affect DNAPL solvent flow in the subsurface is essential for developing models of flow and transport needed for designing remediation and long-term stewardship strategies. We investigate the capability and limitations of low-field nuclear magnetic resonance (NMR) relaxation decay-rate measurements for determining environmental properties affecting DNAPL solvent flow in the subsurface. For in-situ subsurface environmental applications, low-field proton NMR measurements are preferred to conventional high-field techniques commonly used to obtain chemical shift data, because low field measurements are much less degraded by magnetic susceptibility variations between rock grains and pore fluids that significantly interfere with high-field NMR measurements. The research scope includes discriminating DNAPLs in water-wet or solvent-wet environments and the impact of biological processes on their transport mechanisms in porous media. Knowledge of the in situ flow properties and pore distributions of organic contaminants are critical to understanding where and when these fluids will enter subsurface aquifers. Experiments determined that commonly found subsurface DNAPLs containing hydrogen, such as trichloroethylene and dichloroethylene, are detectable and distinguished from water in soils. Related experiments concern the effects of bacterial accumulation in saturated and unsaturated porous media on water and DNAPL pore-size distributions. These include synthetic bio-film matrix as a surrogate bio-film and sand, biological agents to grow biofilms, and multiple pore sizes to determine if bio-films prefer certain pore-size ranges. NMR microscopy focused on imaging a single biofilm in a 1 mm capillary reactor. This system serves as a model for a single large anisotropic pore of a porous media and allows for determination of T2, spin-spin magnetic relaxation behavior within the biofilm. Measurement and analysis protocols along with packing and saturating protocols are evaluated. The anticipated outcome of this research will establish the utility of proton NMR laboratory and field measurements for elucidating flow properties in different porous media, detecting microbiological influence on DNAPLs, and DNAPL pore-fluid partitions under saturated and unsaturated conditions.

  2. Cold core transformer for overload AC transport measurement of high- Tc tapes

    NASA Astrophysics Data System (ADS)

    Šouc, Ján; Gömöry, Fedor; Melišek, Tibor; Tebano, Riccardo

    2002-08-01

    A toroidal 500 VA transformer was developed and constructed for AC-losses measurement of HTC superconducting tapes. Cold ferromagnetic core system with copper primary and superconducting Bi-2223/Ag tape secondary winding, part of which consists of the measured sample, was chosen. Advantages of such system, immersed in LN 2 bath, is its simplicity, compact design and elimination of the additional heat entering through current leads. On the other hand it was necessary to develop a compensation system, which works without moving parts immersed in LN 2. We suggest a new approach to the measurement of the AC-losses for long tapes. AC-losses in the primary winding as well as in the ferromagnetic core and the secondary winding were determined with the help of appropriate voltage taps and pick-up coils.

  3. Characterization of aluminum oxide tunnel barriers by combining transport measurements and transmission electron microscopy imaging

    SciTech Connect

    Aref, T.; Averin, A.; Nguyend, H. Q.; Pekola, J. P. [Low Temperature Laboratory (OVLL), Aalto University School of Science, P.O. Box 13500, 00076 Aalto (Finland); Dijken, S. van; Yao, L. D. [NanoSpin, Department of Applied Physics, Aalto University School of Science, P.O. Box 15100, FI-00076 Aalto (Finland); Ferring, A. [Kirchhoff-Institute for Physics, Heidelberg University, Im Neuenheimer Feld 227, D-69120 Heidelberg (Germany); Koberidze, M.; Nieminen, R. M. [COMP/Department of Applied Physics, Aalto University School of Science, P.O. Box 11100, FI-00076 Aalto, Espoo (Finland); Maisi, V. F., E-mail: ville.maisi@gmail.com [Low Temperature Laboratory (OVLL), Aalto University School of Science, P.O. Box 13500, 00076 Aalto (Finland); Centre for Metrology and Accreditation (MIKES), P.O. Box 9, 02151 Espoo (Finland)

    2014-08-21

    We present two approaches for studying the uniformity of a tunnel barrier. The first approach is based on measuring single-electron and two-electron tunneling in a hybrid single-electron transistor. Our measurements indicate that the effective area of a conduction channel is about one order of magnitude larger than predicted by theoretical calculations. With the second method, transmission electron microscopy, we demonstrate that variations in the barrier thickness are a plausible explanation for the larger effective area and an enhancement of higher order tunneling processes.

  4. Laser-Induced Fluorescence Measurements of Translational Temperature and Relative Cycle Number by use of Optically Pumped Trace-Sodium Vapor

    NASA Technical Reports Server (NTRS)

    Dobson, Chris C.

    1998-01-01

    Sodium fluorescence induced by a narrow bandwidth tunable laser has been used to measure temperature, pressure, axial velocity and species concentrations in wind tunnels, rocket engine exhausts and the upper atmosphere. Optical pumping of the ground states of the sodium, however, can radically alter the shape of the laser induced fluorescence excitation spectrum, complicating such measurements. Here a straightforward extension of rate equations originally proposed to account for the features of the pumped spectrum is to make temperature measurements from spectra taken in pumped vapor. Also determined from the spectrum is the relative fluorescence cycle number, which has application to measurement of diffusion rate and transverse flow velocity. The accuracy of both the temperature and cycle-number measurements is comparable with that of temperature measurements made in the absence of pumping.

  5. Laser-induced fluorescence measurements of translational temperature and relative cycle number by use of optically pumped trace-sodium vapor.

    PubMed

    Dobson, C C

    1999-06-20

    Sodium fluorescence induced by a narrow-bandwidth tunable laser has been used to measure temperature, pressure, axial velocity, and species concentrations in wind tunnels, rocket engine exhausts, and the upper atmosphere. Optical pumping of the ground states of the sodium, however, can radically alter the shape of the laser-induced fluorescence excitation spectrum, complicating such measurements. Here a straightforward extension of rate equations originally proposed to account for the features of the pumped spectrum is used to make temperature measurements from spectra taken in pumped vapor. Also determined from the spectrum is the relative fluorescence cycle number, which has application to measurement of diffusion rate and transverse flow velocity. The accuracy of both the temperature and the cycle-number measurements is comparable with that of temperature measurements made in the absence of pumping. PMID:18320000

  6. Laser-Induced Fluorescence Measurements of Translational Temperature and Relative Cycle Number by use of Optically Pumped Trace-Sodium Vapor

    NASA Technical Reports Server (NTRS)

    Dobson, Chris C.

    1999-01-01

    Sodium fluorescence induced by a narrow-bandwidth tunable laser has been used to measure temperature, pressure, axial velocity, and species concentrations in wind tunnels, rocket engine exhausts, and the upper atmosphere. Optical pumping of the ground states of the sodium, however, can radically alter the shape of the laser-induced fluorescence excitation spectrum, complicating such measurements. Here a straightforward extension of rate equations originally proposed to account for the features of the pumped spectrum is used to make temperature measurements from spectra taken in pumped vapor. Also determined from the spectrum is the relative fluorescence cycle number, which has application to measurement of diffusion rate and transverse flow velocity, The accuracy of both the temperature and the cycle-number measurements is comparable with that of temperature measurements made in the absence of pumping.

  7. Alaska OCS socioeconomic studies program. Technical report number 65. Beaufort Sea transportation systems anlaysis: transportation baseline update and forecast of conditions without the planned lease sale, Beaufort Sea (71). Final technical report

    Microsoft Academic Search

    Eakland

    1981-01-01

    This report updates information on transportation systems contained in the environmental impact statement for the joint Federal-State Beaufort Sea lease sale in 1979. The updated information is intended to provide Bureau of Land Management Outer Continental Shelf staff with base data to which transportation demands for sale 71 can be added.

  8. Comparison between experimental measurements and calculated transport simulation for electron dose distributions inside homogeneous phantoms.

    PubMed

    Borrell-Carbonell, A; Patau, J P; Terrissol, M; Tronc, D

    1980-03-01

    Comparison is made between dosimetric results measured on electron beams delivered by the three medical accelerators Sagittaire, Saturne and Neptune built by CGR MeV with the results simulated by a Monte Carlo method. In depth, the differences are small for moderate energies with scanned electron beams. In the penumbra region, the differences are small in all cases. PMID:7361334

  9. Application of the Stochastic Transport Theory of Neutron and Photon Coupled Fields to Noise Analysis Measurements

    Microsoft Academic Search

    J. L. Muñoz-Cobo; Y. Rugama

    2003-01-01

    The behavior of neutrons and gamma rays in a nuclear reactor or configuration of fissile material can be represented as a stochastic process. The observation of this stochastic process is usually achieved by measuring the fluctuations of the neutron and gamma ray population in the system. The formalism developed in the article (Muñoz Cobo, J. L., Perez, R., Valentine, T.,

  10. UARS/MLS Cloud Ice Measurements: Implications for H2O Transport near the Tropopause

    E-print Network

    Sherwood, Steven

    /Microwave Limb Sounder (UARS/MLS) 203-GHz radiance measurements at tangent pressures between 200 and 46 h clear-sky cases. Unlike infrared/visible cloud observa- tions, the 203-GHz radiances can penetrate most, California Institute of Technology, MS 183-701, 4800 Oak Grove Drive, Pasadena, CA 91109. E-mail: Dong

  11. Mean field limit for bosons with compact kernels interactions by Wigner measures transportation

    SciTech Connect

    Liard, Quentin, E-mail: quentin.liard@univ-rennes1.fr; Pawilowski, Boris, E-mail: boris.pawilowski@univ-rennes1.fr [IRMAR, Université de Rennes I, Campus de Beaulieu, 35042 Rennes Cedex (France)

    2014-09-15

    We consider a class of many-body Hamiltonians composed of a free (kinetic) part and a multi-particle (potential) interaction with a compactness assumption on the latter part. We investigate the mean field limit of such quantum systems following the Wigner measures approach. We prove in particular the propagation of these measures along the flow of a nonlinear (Hartree) field equation. This enhances and complements some previous results of the same type shown in Z. Ammari and F. Nier and Fröhlich et al. [“Mean field limit for bosons and propagation of Wigner measures,” J. Math. Phys. 50(4), 042107 (2009); Z. Ammari and F. Nier and Fröhlich et al., “Mean field propagation of Wigner measures and BBGKY hierarchies for general bosonic states,” J. Math. Pures Appl. 95(6), 585–626 (2011); Z. Ammari and F. Nier and Fröhlich et al., “Mean-field- and classical limit of many-body Schrödinger dynamics for bosons,” Commun. Math. Phys. 271(3), 681–697 (2007)].

  12. Optical analogue for phase-sensitive measurements in quantum-transport experiments

    Microsoft Academic Search

    D. S. Citrin

    1999-01-01

    The Aharonov-Bohm effect has recently been employed to measure the quantum-mechanical phase of an electron propagating ballistically through a quantum dot (QD) contained in one arm of the interferometer [Schuster et al., Nature (London) 385, 417 (1997)]. Jauho and Wingreen [Phys. Rev. B 58, 9619 (1998)] have analyzed this geometry under conditions where the QD is modulated harmonically in time

  13. Monge-Kantorovitch Measure Transportation and Monge-Ampère Equation on Wiener Space

    Microsoft Academic Search

    D. Feyel; A. S. Üstünel

    2004-01-01

    Let ( W,µ, H) be an abstract Wiener space assume two ? i, i=1,2 probabilities on ( W,B( W)). We give some conditions for the Wasserstein distance between ? 1 and ? 2 with respect to the Cameron-Martin space to be finite, where the infimum is taken on the set of probability measures ß on W× W whose first and

  14. MRI measurement of blood-brain barrier transport with a rapid acquisition refocused echo (RARE) method.

    PubMed

    Walton, Jeffrey H; Ng, Kit Fai; Anderson, Steven E; Rutledge, John C

    2015-08-01

    Dynamic Contrast Enhanced (DCE) MRI is increasingly being used to assess changes in capillary permeability. Most quantitative techniques used to measure capillary permeability are based on the Fick equation that requires measurement of signal reflecting both plasma and tissue concentrations of the solute being tested. To date, most Magnetic Resonance Imaging (MRI) methods for acquiring appropriate data quickly rely on gradient recalled echo (GRE) type acquisitions, which work well in clinical low field settings. However, acquiring this type of data on high field small animal preclinical MRIs is problematic due to geometrical distortions from susceptibility mismatch. This problem can be exacerbated when using small animal models to measure blood brain barrier (BBB) permeability, where precise sampling from the superior sagittal sinus (SSS) is commonly used to determine the plasma concentration of the contrast agent. Here we present results demonstrating that a standard saturation recovery rapid acquisition refocused echo (RARE) method is capable of acquiring T1 maps with good spatial and temporal resolution for Patlak analysis (Patlak, 1983) to assess changes in BBB Gd-DTPA permeability following middle cerebral artery occlusion with reperfusion in the rat. This method limits known problems with magnetic susceptibility mismatch and may thus allow greater accuracy in BBB permeability measurement in small animals. PMID:25998382

  15. Correcting acoustic Doppler current profiler discharge measurements biased by sediment transport

    USGS Publications Warehouse

    Mueller, D.S.; Wagner, C.R.

    2007-01-01

    A negative bias in discharge measurements made with an acoustic Doppler current profiler (ADCP) is attributed to the movement of sediment on or near the streambed, and is an issue widely acknowledged by the scientific community. The integration of a differentially corrected global positioning system (DGPS) to track the movement of the ADCP can be used to avoid the systematic bias associated with a moving bed. DGPS, however, cannot provide consistently accurate positions because of multipath errors and satellite signal reception problems on waterways with dense tree canopy along the banks, in deep valleys or canyons, and near bridges. An alternative method of correcting for the moving-bed bias, based on the closure error resulting from a two-way crossing of the river, is presented. The uncertainty in the mean moving-bed velocity measured by the loop method is shown to be approximately 0.6cm/s. For the 13 field measurements presented, the loop method resulted in corrected discharges that were within 5% of discharges measured utilizing DGPS to compensate for moving-bed conditions. ?? 2007 ASCE.

  16. Differential interferometry for measurement of density fluctuations and fluctuation-induced transport (invited)

    Microsoft Academic Search

    L. Lin; W. X. Ding; D. L. Brower; W. F. Bergerson; T. F. Yates

    2010-01-01

    Differential interferometry employs two parallel laser beams with a small spatial offset (less than beam width) and frequency difference (1-2 MHz) using common optics and a single mixer for a heterodyne detection. The differential approach allows measurement of the electron density gradient, its fluctuations, as well as the equilibrium density distribution. This novel interferometry technique is immune to fringe skip

  17. Differential interferometry for measurement of density fluctuations and fluctuation-induced transport (invited)

    Microsoft Academic Search

    L. Lin; W. X. Ding; D. L. Brower; W. F. Bergerson; T. F. Yates

    2010-01-01

    Differential interferometry employs two parallel laser beams with a small spatial offset (less than beam width) and frequency difference (1–2 MHz) using common optics and a single mixer for a heterodyne detection. The differential approach allows measurement of the electron density gradient, its fluctuations, as well as the equilibrium density distribution. This novel interferometry technique is immune to fringe skip

  18. MEASUREMENT AND PREDICTION OF PHOSPHORUS TRANSPORT FROM SWINE MANURE AT THE WATERSHED SCALE

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Livestock production facilities are coming under increased scrutiny with regard to runoff of phosphorus (P) from fields receiving animal manures. The objective of this study was to measure and simulate how swine manure management affects P export from a watershed with intensive swine production. St...

  19. Aerosol transport and dispersion measurements in the near surface boundary layer

    NASA Astrophysics Data System (ADS)

    Hiscox, April Lynn

    The studies presented in this dissertation present new techniques for measuring aerosols in the atmosphere, and the application of these techniques to three different aerosol sources. A methodology for measuring dispersion parameters based on lidar images, which can be used as an efficient way to remotely monitor time variations of plume dispersion parameters, is presented. Lidar images of a smoke plume cross-section over a forest canopy during nighttime conditions are analyzed to estimate vertical dispersion parameters and vertical meander of the plume centerline in the near field. Dispersion parameters 60 meters downwind are found to have a median value of 2.31 meters. Measurements of these parameters have not previously been made outside the restraints of a wind tunnel experiment. A second technique to measure in-plume concentrations based on single wavelength lidar images is also presented. A field study of aerial spray movement and dispersion was used to determine in-plume spray concentrations of very fine droplets applied during calm, stable atmospheric conditions. Supporting meteorology and air turbulence measurements were made simultaneously with 3-D sonic anemometers. The amount of spray material remaining in the air decreased rapidly for 1--2 minutes, and thereafter remained nearly constant and drifted as a definable plume with the slight air currents. Finally, these two techniques are applied to measure near-field spatial dynamics, spread and concentrations of dust plumes emitted during tilling and harvesting of an irrigated cotton field. Combined lidar images are used to form three-dimensional plumes. Plume dynamics and suspended aerosol concentrations are found. Dust plume dynamics varied with atmospheric stability. In particular, plume maximum height was significantly lower during stable conditions. Plume tracking indicated little change in plume cross-sectional area with height under unstable conditions and plume movement depended on wind speed and direction. Horizontal spread rate of the plumes, determined from lidar measured Gaussian dispersion parameters, was less than expected by a factor of seven. Thus, in-plume downwind concentrations were higher than expected. Vertical dispersion was dependent on the rise of "cells" of sensible heat rising from the soil surface.

  20. Understanding the transportation process of tropospheric air entering the stratosphere from direct vertical air motion measurements over Gadanki and Kototabang

    NASA Astrophysics Data System (ADS)

    Narayana Rao, T.; Uma, K. N.; Narayana Rao, D.; Fukao, S.

    2008-08-01

    Long-term measurements of vertical air velocity (w) obtained with VHF wind profilers are utilized to study mean w features as a function of season at two key geographical locations. It is observed that the magnitude of w is always larger than the error/bias contributed by various contaminators. The seasonal mean w profiles at Gadanki and Kototabang show descending (ascending) motion below (above) 8-10 km in most of the seasons. The magnitude of w observed at the above locations is larger than those obtained from radiative budget estimations. The height of wind reversal seems to have a seasonal dependence at Gadanki. Present observations suggest the transportation of air from near surface to the stratosphere is a two-step process: a rapid ascent from the surface to the middle-upper troposphere in convective turrets, and a gentle ascent into the stratosphere. Also, the convection requires to reach an altitude of 10 km, at least at the above locations, and thereafter the prevailing ascent transports the air into the stratosphere.