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1

Numerical Simulation of Electron Transport in Electric and Magnetic Fields for Analysis of Electron Temperature and Number Density Profiles Measured in Argon Magnetic Neutral Loop Discharge Plasma  

Microsoft Academic Search

A Monte Carlo simulation of electron transport in electric and magnetic fields was performed to analyze experimental data of the electron temperature Te and electron number density ne measured in a magnetic neutral loop discharge (NLD) plasma driven in Ar at 0.13 Pa. Te and ne in the vicinity of the substrate holder were measured with a triple probe, and

Hirotake Sugawara; Tsuyoshi Osaga; Hideo Tsuboi; Kiyoshi Kuwahara; Seiji Ogata

2010-01-01

2

Measuring public transport accessibility  

Microsoft Academic Search

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,

Andy Poole

2003-01-01

3

Transport number effects in the transverse tubular system and their implications for low frequency impedance measurement of capacitance of skeletal muscle fibers  

Microsoft Academic Search

Summary It has been shown in an earlier paper that the slow transient decrease in conductance, somtimes referred to as “creep”, obtained with small-to-medium hyperpolarizing current or voltage pulses is due to K+ transport number differences across the walls of the transverse tubular system. Using the same basic numerical analysis and the parameters already obtained experimentally in the previous paper

Peter H. Barry

1977-01-01

4

Measuring Distance of Fuzzy Numbers by Trapezoidal Fuzzy Numbers  

NASA Astrophysics Data System (ADS)

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

Hajjari, Tayebeh

2010-11-01

5

Off-Design Reynolds Number Effects for a Supersonic Transport.  

National Technical Information Service (NTIS)

A high Reynolds number wind tunnel test was conducted to assess Reynolds number effects on the aerodynamic performance characteristics of a realistic, second-generation supersonic transport concept. The tests included longitudinal studies at transonic and...

L. R. Owens R. A. Wahls S. M. Rivers

2005-01-01

6

Measurement of number and size distribution of particles emitted from a mid-sized transportation multipoint port fuel injection gasoline engine  

Microsoft Academic Search

This study was carried out to characterize the engine-exhaust particulate emissions from a typical multipoint port fuel injection gasoline engine used in transportation sector. Though gasoline engine showed no visible tail pipe emissions yet its particle concentrations were comparable to mineral diesel, particularly at high engine loads. Average sizes of particles emitted in gasoline exhaust are found to be way

Tarun Gupta; Abhishek Kothari; Dhananjay Kumar Srivastava; Avinash Kumar Agarwal

2010-01-01

7

Transportation control measure information documents  

SciTech Connect

The document, sponsored by the United States Environmental Protection Agency, is intended to provide information on Transportation Control Measures (TCMs) to transportation planning and air quality planning management and staff at all government levels. The document provides descriptions and examples of the TCMs listed in Section 108(f) of the Clean Air Act. Each TCM is described in terms of its objectives, variation in the ways it may be applied, expected transportation and emissions impacts, and other important implementation and policy considerations that State, regional, and local decision-making agencies will face.

Not Available

1992-03-01

8

Phylogenetic diversity measures based on Hill numbers  

PubMed Central

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

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

2010-01-01

9

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

NASA Astrophysics Data System (ADS)

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.

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

2008-10-01

10

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

NASA Astrophysics Data System (ADS)

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.

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

2008-11-01

11

Measurement Corner Mass, Moles and Avogadro's Number  

ERIC Educational Resources Information Center

Discusses and clarifies the confusion arising from the use of the terms "mass,""volume,""matter,""mole," and "Avogadro's number." Suggests three laboratory activities concerning mass, volume, and number of particles in a given volume. (CS)

Todd, Robert M.

1977-01-01

12

Heat transport measurements in turbulent rotating Rayleigh-Bénard convection  

NASA Astrophysics Data System (ADS)

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.

Liu, Yuanming; Ecke, Robert E.

2009-09-01

13

Heat transport measurements in turbulent rotating Rayleigh-Bénard convection.  

PubMed

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

Liu, Yuanming; Ecke, Robert E

2009-09-23

14

Constituent quark scaling violation due to baryon number transport  

NASA Astrophysics Data System (ADS)

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

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

2011-10-01

15

Measuring Argumentative Reasoning: What's behind the Numbers?  

ERIC Educational Resources Information Center

|The aim of this paper is to develop a more thorough, empirically-based understanding of the differences in measurement of written argumentation when alternative scoring frameworks are employed. Reflective compositions of 127 elementary school children were analyzed using analytic and holistic scales. The scales were derived from Argument Schema…

Reznitskaya, Alina; Kuo, Li-jen; Glina, Monica; Anderson, Richard C.

2009-01-01

16

Measuring Argumentative Reasoning: What's behind the Numbers?  

ERIC Educational Resources Information Center

The aim of this paper is to develop a more thorough, empirically-based understanding of the differences in measurement of written argumentation when alternative scoring frameworks are employed. Reflective compositions of 127 elementary school children were analyzed using analytic and holistic scales. The scales were derived from Argument Schema…

Reznitskaya, Alina; Kuo, Li-jen; Glina, Monica; Anderson, Richard C.

2009-01-01

17

Potential effects of public transport planning measures  

Microsoft Academic Search

The privatization of the Dutch public transport system has brought increasing interest in the effects of planning and marketing measures on travelers’ decision making process. For efficiency reasons, Dutch public transport companies want to know in advance the success of different planning and marketing measures. Also local and regional planners want to have more insight into the effects of their

Peter van der Waerden; Harry Timmermans; Mike Bérénos; Ger Vermeulen

2007-01-01

18

Comparison of fuzzy numbers using a fuzzy distance measure  

Microsoft Academic Search

Abstract A new approach for ranking fuzzy numbers based on a distance measure is introduced. A new class of distance measures for interval numbers that takes into account all the points in both intervals is developed -rst, and then it is used to formulate the distance measure for fuzzy numbers. The approach is illustrated by numerical examples, showing that it

Liem Tran; Lucien Duckstein

2002-01-01

19

Measuring capacity flexibility of a transportation system  

Microsoft Academic Search

This paper describes concepts and techniques to measure the flexibility of a transportation system to accommodate changing demands and traffic patterns. Flexibility is increasingly desired as a characteristic of transport systems, particularly in light of changes in supply chains and traffic patterns, and the concern for the vulnerability of the system to both natural disasters and terrorist actions. Two approaches

Edward K. Morlok; David J. Chang

2004-01-01

20

New Transportation and Service Productivity Measures.  

National Technical Information Service (NTIS)

The Bureau of Labor Statistics (BLS) has developed labor productivity measures and related series for two transportation industries - local trucking without storage (SIC 4212) and public warehousing and storage (SIC 422) - and four service industries - ad...

2003-01-01

21

Guidebook for Sustainability Performance Measurement for Transportation Agencies. NCHRP Report 708.  

National Technical Information Service (NTIS)

This guidebook provides state departments of transportation (DOTs) and other transportation agencies with a practical and easy-to-use approach to identify and apply sustainabilityrelated performance measures, some number of which may already be integrated...

J. DeFlorio J. Potter J. Zietsman T. Ramani V. Reeder

2011-01-01

22

Precision measurement of transport components  

SciTech Connect

We report on the methods and results of magnetic measurements of the centers and moments of magnetic focusing elements for the Final Focus Test Beam at SLAC. The magnetic center is located by observing an electromotive force (EMF) generated on a vibrating wire within the magnetic aperture. It is found that the center can be located with a precision of a few microns. The multipole coefficients can also be measured by using a grid of stretched-wire sweeps, and mapping the time-integrated voltage throughout the aperture. By fitting directly to this map, the dipole, quadrupole, and sextupole terms of the magnetic field are extracted. The design fields of quadrupoles and sextupoles can be measured with a precision better than 0.1%, and the resolution of sextupole aberrations of quadrupole magnets is well below design tolerances. This method has been used to process twenty-five quadrupoles and four sextupoles. Results of these measurements are presented.

Tenenbaum, P.; Cobb, J.K.; Jensen, D.R.; Sawyer, D.; Wagner, W.; Walz, H.V.; Williams, S.H.

1993-04-01

23

Teleportation-based number-state manipulation with number-sum measurement  

SciTech Connect

We examine various manipulations of photon number states which can be implemented by teleportation technique with number-sum measurement. The preparations of the Einstein-Podolsky-Rosen resources as well as the number-sum measurement resulting in projection to certain Bell state may be done conditionally with linear optical elements, i.e., beam splitters, phase shifters, and zero-one-photon detectors. Squeezed vacuum states are used as primary entanglement resource, while single-photon sources are not required.

Kitagawa, Akira; Yamamoto, Katsuji [Department of Nuclear Engineering, Kyoto University, Kyoto 606-8501 (Japan)

2003-10-01

24

Local transport measurements on epitaxial graphene  

NASA Astrophysics Data System (ADS)

Growth of large-scale graphene is still accompanied by imperfections. By means of a four-tip scanning tunneling and electron microscope (4-tip STM/SEM), the local structure of graphene grown on SiC(0001) was correlated with scanning electron microscope images and spatially resolved transport measurements. The systematic variation of probe spacings and substrate temperature has clearly revealed two-dimensional transport regimes of Anderson localization as well as of diffusive transport. The detailed analysis of the temperature dependent data demonstrates that the local on-top nano-sized contacts do not induce significant strain to the epitaxial graphene films.

Baringhaus, J.; Edler, F.; Neumann, C.; Stampfer, C.; Forti, S.; Starke, U.; Tegenkamp, C.

2013-09-01

25

Electron transport measurement in locally strained graphene  

NASA Astrophysics Data System (ADS)

Strain engineering is a promising method for controlling electron transport in graphene; Spatial variation of gauge fields produced by non-uniform strain in graphene causes electron scattering, leading to modulation of the electronic state such as band gap formation. We have succeeded in introducing local strain to graphene, by inserting designed dielectric nanostructures between the graphene sheet and its substrate. [1] The transport measurement of strained graphene has revealed that improvement of the mean free path is crucial for clear demonstration of effect of lattice strain on electron transport.[4pt] [1] H. Tomori et al., Appl. Phys. Express 4, 075102 (2011).

Tomori, Hikari; Kanda, Akinobu; Ootuka, Youiti; Karube, Hiromasa; Kanda, Akinobu

2013-03-01

26

Florida Current Volume Transports from Voltage Measurements  

Microsoft Academic Search

The volume transport of the Florida Current is determined from the motionally induced voltage difference between Florida and Grand Bahama Island. Simultaneous measurements of potential differences and of volume transport by velocity profiling have a correlation of 0.97. the calibration factor is 25 ± 0.7 sverdrups per volt, and the root-mean-square discrepancy is 0.7 sverdrup. The induced voltage is about

Jimmy C. Larsen; Thomas B. Sanford

1985-01-01

27

Florida Current volume transports from voltage measurements  

Microsoft Academic Search

The volume transport of the Florida Current is determined from the motionally induced voltage difference between Florida and Grand Bahama Island. Simultaneous measurements of potential differences and of volume transport by velocity profiling have a correlation of 0.97. The calibration factor is 25 +\\/- 0.7 sverdrups per volt, and the root-mean square discrepancy is 0.7 sverdrup. The induced voltage is

J. C. Larsen; T. B. Sanford

1985-01-01

28

Measurement of turbulent Prandtl number in a round jet  

Microsoft Academic Search

A method which combines two non-intrusive imaging techniques, particle tracking velocimetry (PTV) and laser induced fluorescence (LIF), was used to make simultaneous measurements of velocity and concentration in a neutrally buoyant turbulent round jet. The measurements were made at two different Reynolds numbers, 360 and 4210, and a Schmidt number of 1930. The mean velocity, mean concentration, Reynolds stress, and

Kuang-An Chang; Edwin Cowen

2000-01-01

29

Transport measurements across single nanoparticles  

NASA Astrophysics Data System (ADS)

During this last decade, numerous progresses have been obtained in the chemical synthesis of nanoparticle. Various materials (oxides, chalcogenides) known for their peculiar electronic or magnetic properties -- superconductivity, Mott localization, topological protection -- can now be obtained as nanoparticles through chemical synthesis. These new nano-materials are offering a unique opportunity to study the effect of quantum confinement on unconventional electronic orders. To improve the preparation of samples with single nanoparticles trapped within a nanogap, we developed a new method where nanoparticles are projected in-vacuum on chip circuits covered by nanogap spaced electrodes. Continuous current measurements during the projection allow identifying the trapping of a single nanoparticle within the nanogap. We apply the method for trapping single gold nanoparticles, which led to the observation of Coulomb blockade. We also applied the method to magnetite (Fe3O4) nanoparticles, which allows to study the electric field induced insulator to metal transition in only a few nanoparticles.

Yu, Qian; Cui, Limin; Ulysse, Christian; Mottaghizadeh, Alireza; Zimmers, Alexandre; Aubin, Hervé.

2013-03-01

30

Satellite measurements of aerosol mass and transport  

Microsoft Academic Search

Abstract-The aerosol optical thickness over land is derived from satellite measurements,of the radiance of scattered sunlight. These data are used to estimate the columnar,mass density of particulate sulfur on a day with a large amount,of sulfur. The horizontal transport of the particulate sulfur is calculated using wind vectors measured,with rawins. Key w&d index: Satellite observations, aerosol optical thickness air pollution,

ROBERT S. FRASER; YORAM J. KAUFMAN; R. L. MAHONEY

1984-01-01

31

High-accuracy wave-number measurements in molecular iodine.  

PubMed

Absolute wave-number measurements, with an accuracy of 2-11 parts in 10(9), are presented for 27 (127)I(2) hyperfine-structure lines in the range 5763-6563 A. Individual components were resolved by saturation spectroscopy and their wave numbers measured by a comparison with wavelength standards made using a temperature-stabilized Fabry-Perot interferometer. Good consistency is found among the four accepted (127)I(2)wavelength standards. The result of a previous measurement at 6563 A, which was used as the basis for a Rydberg-constant determination, is also confirmed. PMID:19718101

Hlousek, L; Fairbank, W M

1983-06-01

32

Well resolved pipe flow measurements at extreme Reynolds numbers  

NASA Astrophysics Data System (ADS)

Statistics of the streamwise velocity component were measured at Reynolds numbers ranging from Re?=1x10^3 to Re?=1x10^5 in fully-developed pipe flow. Pipes with two different surface finishes were studied, allowing a comparison between high Reynolds numbers turbulence in the hydraulically smooth and rough regimes. For better spatial resolution a nano- scale thermal anemometry probe (NSTAP) was used to acquire the data. The data gives new insight on pipe flow turbulence at extremely high Reynolds numbers, showing no interaction between the inner and the outer layer. The results also show a Reynolds number dependent outer peak in the turbulent fluctuations, which is only evident at very high Reynolds numbers. These extremely high Reynolds numbers reveal that the scaling of the fluctuations is much more similar to that of the mean velocities than previously believed.

Vallikivi, Margit; Hultmark, Marcus; Bailey, Sean; Smits, Alexander

2011-11-01

33

The Schmidt number as a universal entanglement measure  

NASA Astrophysics Data System (ADS)

The class of local invertible operations is defined, and the invariance of entanglement under such operations is established. For the quantification of entanglement, universal entanglement measures are defined, which are invariant under local invertible transformations. They quantify entanglement in a very general sense. It is shown that the Schmidt number is a universal entanglement measure, which is most important for the general amount of entanglement. For special applications, pseudo-measures are defined to quantify the entanglement useful for a certain quantum task. The entanglement quantification is further specified by operational measures, which include the observables accessible by a given experimental setup.

Sperling, J.; Vogel, W.

2011-04-01

34

Calibrating and Measuring Bedload Transport Using a Magnetic Detection System  

NASA Astrophysics Data System (ADS)

One of the problems in bedload transport research is that no measurement technique has been commonly accepted as superior, and there are no standard protocols. There is a need for continuous bedload measurement to adequately resolve patterns in temporal and spatial variability, especially at high transport rates. Magnetic detection systems are a promising method as they can sense the movement of natural stones, and provide high frequency data in both time and space. A number of magnetic systems have been deployed in the field, but they have not been adequately calibrated. This has limited the analysis to counting the number of pulses, and not allowed confident estimations of the true amount of sediment transport, sediment texture or particle velocities. We developed a series of lab and flume experiments to calibrate the BMD system used by Tunnicliffe et al (2000). Experiments were run with both artificial and natural stones to isolate the effects of particle size, velocity and magnetic content (susceptibility and moment) on the shape of the recorded signal. A large number of experiments were conducted to cover wide range of flow conditions, particle sizes, and particle velocities. The results show that the system is sensitive enough to detect particles down to at least 8mm. Using artificial stones we were able to relate the signal amplitude, width and area to particle size, velocity and magnetic content. These results suggest that the magnetic system can be used to estimate transport rates in natural streams. Work is continuing with natural stones both in the laboratory and the field to further develop of the system. Tunnicliffe, J., Gottesfeld, A.S., and Mohamed, M. 2000. High-resolution measurement of bedload transport, Hydrological Processes, 14, 2631-2643.

Rempel, J.; Hassan, M. A.

2004-12-01

35

Measurements of Turbulent Transport of Fast Ions  

NASA Astrophysics Data System (ADS)

Due to gyroradius averaging and drift-orbit averaging, the transport of fast ions by microturbulence is often smaller than for thermal ions. In this experiment, spatial transport of lithium fast ions [1] with gyroradii of 5.9 cm is studied in the LArge Plasma Device (LAPD). The baseline condition is a uniform quiet plasma; in the comparison condition, the cylindrical plasma column is compressed so the helical fast-ion orbits pass through the turbulent edge region (broadband drift-wave fluctuations with density fluctuations of ˜20%) The fast-ion energy and pitch are varied to study drift averaging. Initial observations indicate that changes in parallel energy are more evident than radial transport. Measurements of the fluctuations by triple, swept Langmuir, and B-dot probes are compared with two-fluid simulations by the BOUT code. Calculations of the expected fast-ion transport in the simulated turbulence will be compared with the experimental profiles. [4pt] [1] Y. Zhang et al. , Rev. Sci. Instrum. 78, 013302 (2007).

Zhou, Shu; Boehmer, Heinrich; Heidbrink, William; McWilliams, Roger; Cater, Troy; Popovich, Pavel; Tripathi, Shreekrishna; Vincena, Steve

2009-11-01

36

PMFCT-2D: A transport simulator for various grid Peclet numbers  

SciTech Connect

Solute transport simulation using numerical models is an important and widespread tool for evaluation of clean-up strategies as well as for prediction of future transport. Classical simulation algorithms for advective-dispersive transport usually introduce large numerical errors where concentrations are lowest. In general, numerical errors tend to spread (disperse) the solute more than physical processes alone. For simulations where the Peclet number (Pe) is greater than about 2, numerical dispersion can be very significant and could lead to erroneous conclusions. Recent numerical techniques for simulating advective transport minimize numerical errors and provide much better solutions. One such technique, Flux-Corrected Transport (FCT), can preserve sharp concentration fronts by virtually eliminating numerical dispersion. In general, it has been observed that as more detailed knowledge of subsurface flow fields is obtained, smaller dispersivity values are needed to match observed and simulated data. However, for many numerical codes the use of small dispersivities is not practical, because it requires fine grids to keep the grid Peclet number limited. A general purpose transport code, PMFCT-2D, has been developed, including a fast and efficient FCT algorithm, to simulate advective-dispersive transport in variably saturated, heterogeneous porous media, with nonuniform aquifer thickness in the third dimension. PMFCT-2D can be used to accurately simulate high Peclet number transport, including purely advective transport (Pe = {infinity}), resulting from transient or steady-state flow conditions. The code is easily coupled to any flow simulator via generated velocity, saturation, and cell thickness fields.

Aimo, N.J.; Oostrom, M. [Pacific Northwest National Lab., Richland, WA (United States)

1997-01-01

37

Exemptions to the Fair Labor Standards Act Transportation Sector, Working Paper Number 10.  

National Technical Information Service (NTIS)

The report will become a chapter in the MWSC technical report on Exemptions from the Fair Labor Standards Act. Discussion of 9 exemptions affecting the transportation sector identifies, when available, the number of employers and employees affected, the s...

C. F. Fritsch

1980-01-01

38

Measuring glomerular number and size in perfused kidneys using MRI.  

PubMed

The goal of this work was to nondestructively measure glomerular (and thereby nephron) number in the whole kidney. Variations in the number and size of glomeruli have been linked to many renal and systemic diseases. Here, we develop a robust magnetic resonance imaging (MRI) technique based on injection of cationic ferritin (CF) to produce an accurate measurement of number and size of individual glomeruli. High-field (19 Tesla) gradient-echo MR images of perfused rat kidneys after in vivo intravenous injection of CF showed specific labeling of individual glomeruli with CF throughout the kidney. We developed a three-dimensional image-processing algorithm to count every labeled glomerulus. MRI-based counts yielded 33,786 ± 3,753 labeled glomeruli (n = 5 kidneys). Acid maceration counting of contralateral kidneys yielded an estimate of 30,585 ± 2,053 glomeruli (n = 6 kidneys). Disector/fractionator stereology counting yielded an estimate of 34,963 glomeruli (n = 2). MRI-based measurement of apparent glomerular volume of labeled glomeruli was 4.89 × 10(-4) mm(3) (n = 5) compared with the average stereological measurement of 4.99 × 10(-4) mm(3) (n = 2). The MRI-based technique also yielded the intrarenal distribution of apparent glomerular volume, a measurement previously unobtainable in histology. This work makes it possible to nondestructively measure whole-kidney glomerular number and apparent glomerular volumes to study susceptibility to renal diseases and opens the door to similar in vivo measurements in animals and humans. PMID:21411479

Beeman, Scott C; Zhang, Min; Gubhaju, Lina; Wu, Teresa; Bertram, John F; Frakes, David H; Cherry, Brian R; Bennett, Kevin M

2011-03-16

39

Interactions of Environmental and Safety Measures for Sustainable Road Transportation.  

National Technical Information Service (NTIS)

This study examined interactions of environmental and safety measures for road transportation. The results showed that a vast majority of the examined measures support both policy objectives and thereby contribute effectively to sustainable transportation...

J. Luoma M. Sivak

2011-01-01

40

Developing Sustainable Transportation Performance Measures for ALDOT.  

National Technical Information Service (NTIS)

Sustainable transportation is generally used to refer to transportation that contributes to the sustainable development of the community that owns and uses the system. The Transportation Research Board defines sustainability as: Sustainability is not abou...

H. A. Toutanji K. Leonard M. Anderson

2013-01-01

41

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

NASA Astrophysics Data System (ADS)

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.

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

2013-10-01

42

Viscous boundary layers in high Rayleigh number convection: A new insight from 3d velocity measurements  

NASA Astrophysics Data System (ADS)

The local transport inside the boundary layers in turbulent convection is one of the keys to understand the scaling of the global heat transport with respect to the temperature gradient and the vertical extent of a wall bounded fluid-mechanical system. We report highly resolved 3d-Laser Doppler Velocimetry measurements in a large-scale Rayleigh-B'enard experiment with air at Rayleigh numbers up to 10^12. The measurements were undertaken in the vicinity of the cooling plate in the central axis of the cylindrical sample. They differ from those reported in the paper du Puits et al [Phys. Rev. E 80, 036318 (2009)] in that all three velocity components have been measured simultaneously. In the present communication we will discuss the results of these measurements and compare them with previous ones as well as with theoretical predictions about the mean velocity profile and the fluctuations in non-isothermal shear layers.

Du Puits, Ronald; Li, Ling; Thess, André.

2010-11-01

43

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

SciTech Connect

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

Fuller, T.F.; Newman, J. (California Univ., Berkeley, CA (United States). Dept. of Chemical Engineering)

1992-05-01

44

High Reynolds number thick axisymmetric turbulent boundary layer measurements  

Microsoft Academic Search

Experimental measurements of the wall shear stress and momentum thickness for thick axisymmetric turbulent boundary layers are presented. The use of a full-scale towing tank allowed zero pressure gradient turbulent boundary layers to be developed on cylinders with diameters of 0.61, 0.89, and 2.5 mm and lengths ranging from 30 m to 150 m. Moderate to high Reynolds numbers (10 4Re ?5, 10

K. M. Cipolla; W. L. Keith

2003-01-01

45

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

SciTech Connect

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

Chakraborty, Nilanjan [Engineering Department, University of Liverpool, Brownlow Hill, Liverpool L69 3GH (United Kingdom); Cant, R.S. [Cambridge University Engineering Department, Trumpington Street, Cambridge CB2 1PZ (United Kingdom)

2009-07-15

46

Journal of Transportation and Statistics, Volume 2, Number 2, December 1999.  

National Technical Information Service (NTIS)

Contents: Letter from the Director of the Bureau of Transportation Statistics; Papers in This Issue - The Structure of Public Transit Costs in the Presence of Multiple Serial Correlation; On the Measurement and Valuation of Travel Time Variability Due to ...

1999-01-01

47

Reynolds number measurements in Rayleigh-Benard convection  

NASA Astrophysics Data System (ADS)

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)..

Funfschilling, Denis

2005-03-01

48

Dialysate volume measurements required for determining peritoneal solute transport  

Microsoft Academic Search

Dialysate volume measurements required for determining peritoneal solute transport. Solute transport parameters for the peritoneal membrane have been previously determined using diaiysate volumes measured by the indicator dilution method. Recent work has shown that the indicator dilution volume (IDV) exceeds true diaiysate volume (TV) because the indicator or index solute is lost from the peritoneal cavity. A peritoneal transport model

John K Leypoldt; Andreas H Pust; Ronald P Frigon; Lee W Henderson

1988-01-01

49

Direct measurement of electrical transport through DNA molecules  

NASA Astrophysics Data System (ADS)

Attempts to infer DNA electron transfer from fluorescence quenching measurements on DNA strands doped with donor and acceptor molecules have spurred intense debate over the question of whether or not this important biomolecule is able to conduct electrical charges. More recently, first electrical transport measurements on micrometre-long DNA `ropes', and also on large numbers of DNA molecules in films, have indicated that DNA behaves as a good linear conductor. Here we present measurements of electrical transport through individual 10.4-nm-long, double-stranded poly(G)-poly(C) DNA molecules connected to two metal nanoelectrodes, that indicate, by contrast, large-bandgap semiconducting behaviour. We obtain nonlinear current-voltage curves that exhibit a voltage gap at low applied bias. This is observed in air as well as in vacuum down to cryogenic temperatures. The voltage dependence of the differential conductance exhibits a peak structure, which is suggestive of the charge carrier transport being mediated by the molecular energy bands of DNA.

Porath, Danny; Bezryadin, Alexey; de Vries, Simon; Dekker, Cees

2000-02-01

50

Automatic trajectory measurement of large numbers of crowded objects  

NASA Astrophysics Data System (ADS)

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

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

2013-06-01

51

Effects of Lewis Number on Scalar Dissipation Transport and Its Modeling in Turbulent Premixed Combustion  

Microsoft Academic Search

The effects of Lewis number (Le) on scalar dissipation rate transport of the reaction progress variable have been studied using 3-dimensional DNS data of freely propagating turbulent premixed flames with global Lewis number ranging from 0.34 to 1.2. It has been found that the effects of dilatation rate become increasingly strong with decreasing Le, and is particularly strong for the

N. Chakraborty; N. Swaminathan

2010-01-01

52

Transport and deposition of ellipsoidal fibers in low Reynolds number flows  

Microsoft Academic Search

The motion of elongated, ellipsoidal fibers in low Reynolds number flows was studied using a computational modeling approach. The computer model resolved the coupled translational and rotational motion of fibers in laminar flows. The computational model was applied in a circular duct and the transport and deposition of ellipsoidal fibers with different sizes and aspect ratios were simulated. An experimental

Lin Tian; Goodarz Ahmadi; Zuocheng Wang; Philip K. Hopke

53

Silver and Sodium Ion Transport Numbers into Pyrex from Binary Nitrate Melts.  

National Technical Information Service (NTIS)

The cation transport numbers of sodium and silver ion from mixed melts of the nitrates into a Pyrex membrane at 318C are found to be accurately equal to the corresponding cation mole fractions in the melt over the whole range of compositions. This result ...

A. G. Keenan W. H. Duewer

1968-01-01

54

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

Federal Register 2010, 2011, 2012, 2013

...DEPARTMENT OF TRANSPORTATION Federal Railroad Administration Waiver Petition Docket Numbers FRA-2011-0002, CSX Transportation Railroad, and FRA-2004-17565, Union Pacific Railroad; Public Hearing On February 23,...

2011-07-15

55

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

SciTech Connect

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

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

2007-12-03

56

Measurements of Turbulent Transport of Fast Ions  

Microsoft Academic Search

Due to gyroradius averaging and drift-orbit averaging, the transport of fast ions by microturbulence is often smaller than for thermal ions. In this experiment, spatial transport of lithium fast ions [1] with gyroradii of 5.9 cm is studied in the LArge Plasma Device (LAPD). The baseline condition is a uniform quiet plasma; in the comparison condition, the cylindrical plasma column

Shu Zhou; Heinrich Boehmer; William Heidbrink; Roger McWilliams; Troy Cater; Pavel Popovich; Shreekrishna Tripathi; Steve Vincena

2009-01-01

57

Measurement of Hydrocarbon Transport in Bacteria  

Technology Transfer Automated Retrieval System (TEKTRAN)

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

58

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...

59

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...

60

Measures of International Transport Cost for OECD Countries  

Microsoft Academic Search

This paper presents new estimates of country-specific international transport costs for 21 OECD countries over the period 1973-2005. The methodology is based on direct measures of air, maritime, and road transport costs rather than on cif\\/fob ratios or other balance of payments data employed in previous studies. Transport costs are calculated as costs per kilogramme for each mode of transport

Stephen S. Golub; Brian Tomasik

2008-01-01

61

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

NASA Astrophysics Data System (ADS)

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.

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

2013-10-01

62

PET measurement of glucose membrane transport using labeled analogs: Distinction of transport from metabolic processes  

Microsoft Academic Search

Carrier mediated glucose transport rates across brain capillary and myocardial cell membranes are many times higher than those expected for simple diffusion, and transport regulation can be an important determinant of tissue metabolic status. The authors have investigated the use of glucose analogs and dynamic positron tomography for the non-invasive measurement of unidirectional membrane transport rates. If analog extraction is

J. E. Holden; R. A. Koeppe; S. J. Gatley

1984-01-01

63

Solving a Multi Objective Transportation Problem(MOTP) Under Fuzziness on Using Interval Numbers  

NASA Astrophysics Data System (ADS)

In this paper we present a solution procedure of the Multi Objective Transportation Problem(MOTP) where the coefficients of the objective functions, the source and destination parameters which determined by the decision maker(DM) are symmetric triangular fuzzy numbers. The constraints with interval source and destination parameters have been converted in to deterministic ones. A numerical example is provided to illustrate the approach.

Saraj, Mansour; Mashkoorzadeh, Feryal

2010-09-01

64

Transport processes as manifested in satellite and lidar aerosol measurements  

NASA Astrophysics Data System (ADS)

A large increase in stratospheric aerosol data has become available recently from the SAM II and SAGE satellite sensors and the impetus from increased volcanic perturbations. Six years of SAM II and nearly 3 years of SAGE measurements have been accumulated. The increase in large volcanic eruptions since 1979 has caused an acceleration of new data sets from worldwide lidars and airborne lidar campaigns and from various airborne in situ measurements. The SAM II and SAGE data sets show the tropical stratosphere as a source for background stratospheric aerosols, and midlatitudes as a possible sink. Analyses of SAM II data show that the aerosol within the northern wintertime polar vortex becomes isolated from the outside. Subsidence occurs within the vortex, changing the vertical aerosol distribution over the winter period. SAM II and SAGE data show that the aerosol is transported in the stratosphere from low to high latitudes in wintertime. Entry regions of tropospheric air in the Tropics are also evident in the SAGE data as shown by stratospheric cirrus clouds being formed well above the local tropopause. Nature has provided over the past 5 years a number of large volcanic eruptions which spewed tons of new aerosol into the stratosphere. These eruptions have occurred at various latitudes which allow transport differences to be studied. Satellite and lidar aerosol data will be used to describe the stratospheric motions of aerosols produced after these violet volcanic eruptions.

McCormick, M. P.

1985-12-01

65

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

National Technical Information Service (NTIS)

This paper discusses Reynolds number scaling for aerodynamic parameters including force and wing pressure measurements. A full-span model of the Boeing 777 configuration was tested at transonic conditions in the National Transonic Facility (NTF) at Reynol...

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

2002-01-01

66

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

NASA Astrophysics Data System (ADS)

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

Jeyashekar, Nigil Satish

67

Appropriate burnup measurements for transportation burnup credit.  

National Technical Information Service (NTIS)

This paper addresses two of the measurement specifications used in analyzing spent fuel packages to gain burnup credit. The philosophy and calculation of rejection criteria and measurement accuracy are discussed. Any assembly for which the declared measur...

D. Lancaster E. Fuentes

1997-01-01

68

Optical measurement techniques for high Reynolds number train investigations  

Microsoft Academic Search

This article reports on experimental aerodynamic investigations on a generic high-speed train configuration performed within two different wind tunnels. Both wind tunnels are specialized facilities for high Reynolds number investigations and offer low turbulence levels. The wind tunnels are the cryogenic wind tunnel located in Cologne (KKK) and in the high-pressure wind tunnel located in Göttingen (HDG). Both facilities are

S. Loose; H. Richard; J. Bosbach; M. Thimm; W. Becker; M. Raffel

2006-01-01

69

Interfacing numbers with people: lessons in quality measurement techniques  

Microsoft Academic Search

The Department of Defence (DOD) defines total quality management (TQM) as an integrated approach, in which isolated expertise in one area creates a limited result. The secret of successful TQM is integration of all elements. Some of the most important lessons learned have centered around the issue of interfacing people with numbers. For engineers, data that can translate vague generalities,

Annette Simmons

1994-01-01

70

Infrared measuring equipment with a limited number of communication channels  

Microsoft Academic Search

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

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

1973-01-01

71

Measurement of gas transport properties for chemical vapor infiltration  

Microsoft Academic Search

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

T. L. Starr; N. Hablutzel

1996-01-01

72

Performance measurement in transport sector analysis  

Microsoft Academic Search

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

Margarita Išoraite

2004-01-01

73

Transport coefficients for the shear dynamo problem at small Reynolds numbers  

SciTech Connect

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

Singh, Nishant K. [Raman Research Institute, Sadashivanagar, Bangalore 560 080 (India); Joint Astronomy Programme, Indian Institute of Science, Bangalore 560 012 (India); Sridhar, S. [Raman Research Institute, Sadashivanagar, Bangalore 560 080 (India)

2011-05-15

74

Electron density measurements during ion beam transport on Gamble II  

Microsoft Academic Search

Summary form only given. High-sensitivity laser interferometry was used to measure the electron density created when an intense proton beam (100 kA, 1 MeV, 50 ns) from the Gamble II generator was transported through low-pressure gas as part of a project investigating self-pinched transport (SPT) of intense ion beams. This measurement is non-perturbing and sufficiently quantitative to allow benchmarking of

B. V. Weber; D. D. Hinshelwood; J. M. Neri; P. F. Ottinger; D. V. Rose; S. J. Stephanakis; F. C. Young

1999-01-01

75

The number comb for a soil physical properties dynamic measurement  

NASA Astrophysics Data System (ADS)

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

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

2012-04-01

76

Impedance measurements for photon number resolving Transition-Edge Sensors  

NASA Astrophysics Data System (ADS)

The complex impedance measurement technique is an established method for the characterisation of Transition-Edge Sensors (TES) bolometers and microcalorimeters. In this report this technique is applied at frequencies up to 250kHz to Ti/Pd and Ti/Au Transition-Edge Sensors, in the optical and near-infrared wavelength range, to obtain a complete frequency response in the complex plane. From these measurements we obtain information about the logarithmic temperature sensitivity ?, the logarithmic current sensitivity ? and on the device thermal parameters, heat capacity C, thermal conductance G and the effective response time ? eff. All these parameters provide a reasonable understanding of the two different detectors and a discussion about the main differences is also reported.

Taralli, E.; Portesi, C.; Lolli, L.; Rajteri, M.; Monticone, E.; Novikov, I.; Beyer, J.

2012-02-01

77

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

PubMed

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. Copyright © 2013 John Wiley & Sons, Ltd. PMID:23740818

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

2013-06-05

78

Transported acid aerosols measured in southern Ontario  

NASA Astrophysics Data System (ADS)

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

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

79

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

NASA Astrophysics Data System (ADS)

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

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

80

Thermal Transport Measurements of Individual Multiwalled Nanotubes  

Microsoft Academic Search

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

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

2001-01-01

81

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

Code of Federal Regulations, 2013 CFR

... false What are agency performance measures for transportation? 102-117.270...117-TRANSPORTATION MANAGEMENT Performance Measures § 102-117.270 What are agency performance measures for transportation? (a) Agency...

2013-01-01

82

Transport Measurements on Individual Branched Nanostructures  

NASA Astrophysics Data System (ADS)

We have made electrical measurements on individual branched (``Y-junction") carbon nanotubes. After isolation on silicon substrates and identification via electron microscopy, photo and e-beam lithography were used to deposit metal electrodes (e.g. Au/Ti) onto individual branches of the nanostructures, including 4-probe configurations across a branch point (Y-junction). Various post-processing procedures, such as rapid thermal annealing and electron beam welding, were employed in attempts to improve contact resistances. Four-probe I-V measurements at room temperature yield varied intrinsic conductivity in these nanostructures (resistances between 10^4 and 10^7?). Transmission microscopy reveals a fishbone internal structure, which could be responsible for the low conductance. We also report on the construction of ``divining rod'' cantilevers out of these branched nanotubes, using an etch-well technique, toward potential SPM applications, and on similar attempts using inorganic (e.g. ZnO2) nanowires.

Sun, Yong; Li, Wenzhi; Naughton, M. J.

2005-03-01

83

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

NASA Astrophysics Data System (ADS)

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.

Nawroth, Janna; Dabiri, John

2010-11-01

84

Lessons learned from the jellyfish: Fluid transport at intermediate Reynolds numbers  

NASA Astrophysics Data System (ADS)

Biologically inspired hydrodynamic propulsion and maneuvering strategies promise the advancement of medical implants and novel robotic tools. We have chosen juvenile jellyfish as a model system for investigating fluid dynamics and morphological properties underlying fluid transport by an elastic system 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 a synthetic jellyfish, that is, a rhythmically actuated elastomer capable of generating efficient feeding and propulsion currents. The main challenges here are (1) to derive a body shape and deformation suitable for effective fluid transport under physiological fluid conditions, (2) to understand the mechanical properties of actuator and elastomer to derive a design capable of the desired deformation, (3) to establish adequate 3D kinematics of power and recovery stroke, and (4) to evaluate the performance of the design.

Nawroth, Janna; Dabiri, John

2011-11-01

85

THE MEASUREMENT OF SAND TRANSPORT BY MEANS OF RADIOACTIVE TRACERS  

Microsoft Academic Search

Experiments on the development of a method for measuring the sand ; transport in rivers by means of radioactive tracers are described. In the ; method, the mean velocity is determined from the rate of displacement of th ; centroid of a marked cloud of fluid. The spread of radiodiactive sana was ; measured from a transverse strip of the

M. J. Crickmore; G. H. Lean

1962-01-01

86

The Measurement of Sand Transport by Means of Radioactive Tracers  

Microsoft Academic Search

Experiments are described which have for their object the development of a method of measuring the sand transport in rivers by means of radioactive tracers. The method used is analogous to that which has been used for the measurement of water discharge in which the mean velocity is determined from the rate of displacement of the centroid of a marked

M. J. Crickmore; G. H. Lean

1962-01-01

87

Copy number variations of the ATP-binding cassette transporter ABCC6 gene and its pseudogenes  

PubMed Central

Background The ATP-binding cassette transporter ABCC6 gene is located on chromosome 16 between its two pseudogenes (ABCC6P1 and ABCC6P2). Previously, we have shown that ABCC6P1 is transcribed and affects ABCC6 at the transcriptional level. In this study we aimed to determine copy number variations of ABCC6, ABCC6P1 and ABCC6P2 in different populations. Moreover, we sought to study the transcription pattern of ABCC6 and ABCC6 pseudogenes in 39 different human tissues. Findings Genomic DNA from healthy individuals from five populations, Chinese (n?=?24), Middle East (n?=?20), Mexicans (n?=?24), Caucasians (n?=?50) and Africans (n?=?24), were examined for copy number variations of ABCC6 and its pseudogenes by pyrosequencing and quantitative PCR. Copy number variation of ABCC6 was very rare (2/142; 1.4%). However, one or three copies of ABCC6P1 were relatively common (3% and 8%, respectively). Only one person had a single copy of ABCC6P2 while none had three copies. In Chinese, deletions or duplications of ABCC6P1 were more frequent than in any other population (9/24; 37.5%). The transcription pattern of ABCC6P2 was highly similar to ABCC6 and ABCC6P1, with highest transcription in liver and kidney. Interestingly, the total transcription level of pseudogenes, ABCC6P1?+?ABCC6P2, was higher than ABCC6 in most tissues, including liver and kidney. Conclusions Copy number variations of the ABCC6 pseudogenes are quite common, especially in populations of Chinese ancestry. The expression pattern of ABCC6P2 in 39 human tissues was highly similar to that of ABCC6 and ABCC6P1 suggesting similar regulatory mechanisms for ABCC6 and its pseudogenes.

2012-01-01

88

The effect of the number of parallel DNA molecules on electric charge transport through 'standing DNA'  

NASA Astrophysics Data System (ADS)

We present morphological and electrical characterization of double-stranded DNA (dsDNA) molecules covalently bound to two metal electrodes: an underlying gold surface and a gold nanoparticle (GNP). Conductive atomic force microscope (cAFM) with a metallized tip is used to perform current-voltage (I-V) measurements through dsDNA molecules, connected to GNPs of different diameters 5, 10 and 20 nm. The number of DNA molecules coating the GNP is expected to vary with the surface area of the GNP. This number and the portion of the GNP surface area enabling hybridization of the DNA determine the number of DNA molecules connecting the GNP to the gold surface. The larger the diameter of the GNP the higher the expected number of dsDNA molecules connecting it to the gold surface and thus the expected current. Our results show similar currents for all three GNP sizes, indicating that current flows through the same number of molecules regardless of the diameter of the measured GNP. The measured currents, 220 nA at 2 V, are in accordance with our previous reports (Cohen et al 2005 Proc. Natl Acad. Sci. USA 102 11589-93 Cohen et al 2006 Faraday Discuss. 131 367-76) in which we demonstrated the validity of the experimental system. In particular, for the 5 nm GNP, we conclude that the current possibly flows through two to three molecules, likely only one, and that a single short dsDNA molecule can support at least ~70 nA, and probably 220 nA.

Ullien, Daniela; Cohen, Hezy; Porath, Danny

2007-10-01

89

Measurement of gas transport properties for chemical vapor infiltration  

SciTech Connect

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.

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

1996-12-01

90

Multiphase fluid dynamics and transport processes of low capillary number cavitating flows  

NASA Astrophysics Data System (ADS)

To better understand the multiphase fluid dynamics and associated transport processes of cavitating flows at the capillary number of 0.74 and 0.54, and to validate the numerical results, a combined computational and experimental investigation of flows around a hydrofoil is studied based on flow visualizations and time-resolved interface movement. The computational model is based on a modified RNG k-? model as turbulence closure, along with a vapor-liquid mass transfer model for treating the cavitation process. Overall, favorable agreement between the numerical and experimental results is observed. It is shown that the cavitation structure depends on the interaction of the water-vapor mixture and the vapor among the whole cavitation stage, the interface between the vapor and the two-phase mixture exhibits substantial unsteadiness. And, the adverse motion of the interface relates to pressure and velocity fluctuations inside the cavity. In particular, the velocity in the vapor region is lower than that in the two-phase region.

Li, Xiangbin; Wang, Guoyu; Yu, Zhiyi; Shyy, Wei

2009-04-01

91

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

SciTech Connect

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.

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

2012-02-14

92

Electronic measurement and control of spin transport in silicon  

NASA Astrophysics Data System (ADS)

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 semiconductors, excluding a wide range of non-magnetic semiconductors with indirect bandgaps. Most notable in this group is silicon, Si, which (in addition to its market entrenchment in electronics) has long been predicted a superior semiconductor for spintronics with enhanced lifetime and transport length due to low spin-orbit scattering and lattice inversion symmetry. Despite this promise, a demonstration of coherent spin transport in Si has remained elusive, because most experiments focused on magnetoresistive devices; these methods fail because of a fundamental impedance mismatch between ferromagnetic metal and semiconductor, and measurements are obscured by other magnetoelectronic effects. Here we demonstrate conduction-band spin transport across 10?m undoped Si in a device that operates by spin-dependent ballistic hot-electron filtering through ferromagnetic thin films for both spin injection and spin detection. As it is not based on magnetoresistance, the hot-electron spin injection and spin detection avoids impedance mismatch issues and prevents interference from parasitic effects. The clean collector current shows independent magnetic and electrical control of spin precession, and thus confirms spin coherent drift in the conduction band of silicon.

Appelbaum, Ian; Huang, Biqin; Monsma, Douwe J.

2007-05-01

93

Optical Measurement of Osmotic Water Transport in Cultured Cells  

Microsoft Academic Search

Methodology was developed to measure osmotic water permeability in monolayer cultured cells and applied to examine the proposed role of glucose transporters in the water pathway (1989. Proc. Natl. Acad. Sci. USA. 86:8397-8401). J774 macrophages were grown on glass coverslips and mounted in a channel-type perfusion chamber for rapid fluid exchange without cell detachment. Relative cell volume was measured by

MIRIAM ECHEVARRIA; A. S. VERKMAN

94

Measurement of parallel transport of B+ and Al2+ impurities in a linear He+ plasma  

NASA Astrophysics Data System (ADS)

Laser ablation is used to inject trace quantities (˜1%) of boron or aluminum impurities into steady-state, cylindrical He+ plasmas. The He+ plasmas have an axial flow velocity of about 2 × 103 m/s, corresponding to Mach number M ˜ 0.2. The parallel flow of the resulting B+ or Al2+ impurity ions is measured directly using photomultiplier tubes with line filters. Perpendicular loss of the impurity ions is estimated indirectly from particle conservation. Rapid (<100 ?s) entrainment of B+ in the background flow is observed; Al2+ ions appear to accelerate up to perhaps half the background flow velocity in the same time period. Preliminary comparisons with expected transport rates indicate that the observed parallel transport is ?2-3× faster than expected from classical collisional transport, while perpendicular transport appears slightly slower than expected.

Hollmann, E. M.; Umstadter, K. R.; Doerner, R. P.; Munoz, J.; Nishijima, D.; Pigarov, A. Yu.

2011-08-01

95

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

SciTech Connect

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.

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

1992-12-31

96

Charge transport measurements of vertically aligned carbon nanofibers  

NASA Astrophysics Data System (ADS)

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.

Zhang, Lan

97

Long-Term Options and Forecasts for Transport in Europe - Summary Report. FAST Series Number 8.  

National Technical Information Service (NTIS)

The results of a research project on long-term options and forecasts for transport in Europe are presented in summary form. The project was to identify the major long-term prospects, problems and risks in international transport in Europe, and on this bas...

R. Allport K. Gwilliam

1982-01-01

98

Direct measurement of hole transport dynamics in DNA  

NASA Astrophysics Data System (ADS)

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.

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

2000-07-01

99

Ion energy analyzer for measurement of ion turbulent transport.  

PubMed

For local measurement of radial ion thermal transport, we developed a novel time-resolved gridded ion energy analyzer. The turbulent thermal flux is obtained by correlating fluctuations of ion temperature, plasma density and plasma velocity. The simultaneous measurement of the ion current fluctuations from an ion energy analyzer ?(IEA)(t) and the fluctuation of ion saturation current from a conventional Langmuir probe ?(LP)(t) allow us to determine local fluctuations of ion temperature T(i)(t). To reduce the effect of plasma potential fluctuations in the energy analyzer measurements, we use special a compensative circuit loop. PMID:23126762

Sokolov, V; Sen, A K

2012-10-01

100

LIF Diagnostic for Measuring Beam-Transport Magnetic Fields  

NASA Astrophysics Data System (ADS)

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.

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

1996-11-01

101

Fuzzy risk analysis based on similarity measures of generalized fuzzy numbers  

Microsoft Academic Search

In this paper, we present a new method for fuzzy risk analysis based on similarity measures of generalized fuzzy numbers. Firstly, we present a method called the simple center of gravity method (SCGM) to calculate the center-of-gravity (COG) points of generalized fuzzy numbers. Then, we use the SCGM to propose a new method to measure the degree of similarity between

Shi-Jay Chen; Shyi-Ming Chen

2003-01-01

102

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

SciTech Connect

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.

NONE

1995-08-01

103

LIF Diagnostic for Measuring Beam-Transport Magnetic Fields  

NASA Astrophysics Data System (ADS)

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).

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

1997-11-01

104

Millisecond measurement of transport during and after an electroporation pulse.  

PubMed Central

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.

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

1995-01-01

105

Tiltakspakker for Kollektivtransport 1996-2000. Effekter av Informasjonstiltakene (Public Transport 1996-2000. The Effect of Information Measures).  

National Technical Information Service (NTIS)

T0I has evaluated the effect of the information measures in 11 packages of measures for public transport. Better information leads to passengers traveling more, while poorer information leads to a drop in the number of passengers. The traditional channels...

A. Ruud

2005-01-01

106

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

PubMed

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

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

2003-10-01

107

Continuous phosphorus measurements reveal catchment-scale transport processes.  

NASA Astrophysics Data System (ADS)

A small fraction of the nutrients used for agriculture is transported by rivers and artificial drainage networks to downstream waters. In lakes and coastal seas such as the Baltic Sea and the Gulf of Mexico these nutrients cause large-scale algal blooms and hypoxia and thus are a major environmental hazard. In this presentation we focus on the transport of phosphorus from agricultural fields. An improved understanding of the flow routes and stores of phosphorus within a catchment and of the chemical properties of these phosphorus stores and fluxes are crucial for developing effective remediation and mitigation strategies. In the Hupsel brook agricultural catchment in the Netherlands (6.5 km2), we measured dissolved and total phosphorus every 15 minutes for a 1 year period. Many studies have found that phosphorus is mainly transported adsorbed to sediments and other oxide surfaces. We, however, show for the Hupsel brook catchment that the affinity for phosphorus to bind with particles has a strong seasonality. During the winter season the ratio dissolved versus bound phosphorus is approximately 3:2 (i.e. more dissolved than adsorbed), while during the summer this ratio reduces to 1:5 (i.e. more adsorbed than dissolved), with variations during discharge events. In our presentation we will use the weekly sampling of other ions at several locations within the catchment, chemical analyses of transported sediments and continuous water temperature and discharge records to shed some light on the biological, chemical and physical processes that drive catchment-scale transport of phosphorus for this agricultural stream.

van der Velde, Y.; Rozemeijer, J. C.

2012-04-01

108

Application of flux-corrected transport (FCT) to high Rayleigh number natural convection in a porous medium  

SciTech Connect

A numerical technique designed to solve a wide class of convectively dominated flow problems is applied to natural convective flow in a porous medium at large Rayleigh number. The technique is a finite difference method based on flux-corrected transport (FCT) and possesses four desirable numerical properties: stability, accuracy, monotonicity, and conservation. Steady natural convection is investigated for Rayleigh numbers as large as 10,000. An efficient methodology for obtaining steady state solutions is illustrated. A simulation is performed for transient thermal convection at a Rayleigh number of 2500. Transient natural convection involving both heat and mass transfer is illustrated for a Rayleigh number of 2500, Lewis number of 2, and buoyancy ratio of 0.1. All simulations are performed in a square cavity with heated vertical side walls. 17 refs.

Gross, R.J.; Baer, M.R.; Hickox, C.E.

1986-01-01

109

Nature’s Microfluidic Transporter: Rotational Cytoplasmic Streaming at High Péclet Numbers  

Microsoft Academic Search

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

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

2008-01-01

110

WATER SPRAY AND IMMERSION IN CHEMICAL SANITIZER TO LOWER BACTERIAL NUMBERS ON BROILER TRANSPORT COOP FLOORING  

Technology Transfer Automated Retrieval System (TEKTRAN)

Broiler transport cages become soiled with feces during use. Feces contaminated with Campylobacter can cause cross contamination of flocks that were previously free of this important human pathogen. Because washing and sanitizing cages requires large amounts of water and is not always effective en...

111

Consequences of Motor Copy Number on the Intracellular Transport of Kinesin1Driven Lipid Droplets  

Microsoft Academic Search

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 kine- sins and that cargos with more motors move faster andforlongerdistances;concreteevidence,however, is sparse. Here we rigorously test these notions using lipid droplets in Drosophila embryos. We first employ antibody inhibition, genetics, biochemistry, and parti- cle tracking

George T. Shubeita; Susan L. Tran; Jing Xu; Michael Vershinin; Silvia Cermelli; Sean L. Cotton; Michael A. Welte; Steven P. Gross

2008-01-01

112

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

SciTech Connect

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

Mukaide, Taihei; Watanabe, Masatoshi; Takada, Kazuhiro; Fukuda, Kazunori; Noma, Takashi [Nanomaterials Technology Development Center, Canon Inc., 30-2, Shimomaruko 3-chome, Ohta-ku, Tokyo 146-8501 (Japan); Iida, Atsuo [Photon Factory, Institute of Materials Structure Science, High Energy Accelerator Research Organization, 1-1, Oho Tsukuba, Ibaraki 305-0801 (Japan)

2011-03-14

113

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

NASA Astrophysics Data System (ADS)

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

Polat, Recep; Içelli, Orhan

2010-04-01

114

Prediction of cloud condensation nucleus number concentration using measurements of aerosol size distributions and composition and light scattering enhancement due to humidity  

Microsoft Academic Search

A cloud condensation nucleus (CCN) closure experiment is carried out using data from the Chebogue Point, Nova Scotia, ground site during the International Consortium for Atmospheric Research on Transport and Transformation (ICARTT) field experiment in 2004. The number concentration of CCN at five supersaturations (?0.07% to ?0.5%) is predicted from measurements of aerosol size distribution, composition, and hygroscopic growth and

Barbara Ervens; Michael Cubison; Elisabeth Andrews; Graham Feingold; John A. Ogren; Jose L. Jimenez; Peter DeCarlo; Athanasios Nenes

2007-01-01

115

Prediction of cloud condensation nucleus number concentration using measurements of aerosol size distributions and composition and light scattering enhancement due to humidity  

Microsoft Academic Search

A cloud condensation nucleus (CCN) closure experiment is carried out using data from the Chebogue Point, Nova Scotia, ground site during the International Consortium for Atmospheric Research on Transport and Transformation (ICARTT) field experiment in 2004. The number concentration of CCN at five supersaturations (~0.07% to ~0.5%) is predicted from measurements of aerosol size distribution, composition, and hygroscopic growth and

Barbara Ervens; Michael Cubison; Elisabeth Andrews; Graham Feingold; John A. Ogren; Jose L. Jimenez; Peter DeCarlo; Athanasios Nenes

2007-01-01

116

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

Microsoft Academic Search

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

Gregory M. Cole; Thomas J. Mueller

1990-01-01

117

Some Algebraic Properties And A Distance Measure For Interval-Valued Fuzzy Numbers  

Microsoft Academic Search

In this paper, we generalize results of Wang and Li [Fuzzy Sets and Systems 98 (1998) 331] on interval-valued fuzzy numbers and extend their operations with simple proofs. We also consider some algebraic properties and a distance measure for interval-valued fuzzy numbers.

Dug Hun Hong; Sungho Lee

2002-01-01

118

Maximal entanglement of squeezed vacuum states via swapping with number-phase measurement  

SciTech Connect

We propose a method to refine entanglement via swapping from a pair of squeezed vacuum states by performing the Bell measurement of number sum and phase difference. The resultant states are maximally entangled by adjusting the two squeezing parameters to the same value. We then describe the teleportation of number states by using the entangled states prepared in this way.

Kitagawa, Akira; Yamamoto, Katsuji [Department of Nuclear Engineering, Kyoto University, Kyoto 606-8501 (Japan)

2002-11-01

119

The number of photon counting measurements, the visibility and the intensity  

Microsoft Academic Search

Summary  We calculate, under certain ideal conditions, the number of counting measurements,n\\u000a c, necessary to guarantee a measurement of the visibility of an interference pattern within a specified precision ?, with a\\u000a specified probabilityP\\u000a 0, in a single experimental run. Also we find that if the light intensity for an ideal laser is decreased (or increased), then\\u000a the expected number of

V. Buonomano

1985-01-01

120

Continuous measurement of atom-number moments of a Bose-Einstein condensate by photodetection  

SciTech Connect

We propose a measurement scheme that allows determination of even moments of a Bose-Einstein condensate (BEC) atom number, in a ring cavity, by continuous photodetection of an off-resonant quantized optical field. A fast cavity photocounting process limits the heating of atomic samples with a relatively small number of atoms, being convenient for BECs on microchip scale applications. The measurement back-action introduces a counting-conditioned phase damping, suppressing the condensate typical collapse and revival dynamics.

Prataviera, G.A. [Departamento de Fisica, CCET, Universidade Federal de Sao Carlos, Via Washington Luiz Km 235, Sao Carlos, 13565-905, SP (Brazil); Oliveira, M.C. de [Instituto de Fisica 'Gleb Wataghin', Universidade Estadual de Campinas, 13083-970, Campinas-SP (Brazil)

2004-07-01

121

Electron Temperature Measurements and Energy Transport in SSPX  

NASA Astrophysics Data System (ADS)

Time-resolved measurements (<100 ?s) have been made with a multi-pulse Thomson scattering diagnostic in the SSPX spheromak experiment, to obtain radial electron density and temperature profile during plasma formation and sustainment. In most discharges three regimes are observed with respect to Te and ne evolution. Initially there is a cold (<100 eV) formation phase, followed by a hollow Te profile with maximum temperatures 100-200 eV, and a final heat-up and cool-down phase where we obtain the highest plasma temperatures (350+ eV). The transition from hollow to peaked Te is quite sharp (˜50 ?s) and the recent upgrade to double-pulse Thomson scattering (˜40 ?s between pulses) facilitates capturing this transition. We also present simulations using the CORSICA code where the equilibrium is kept fixed and the discharge is evolved to observe the change in temperature profiles for different transport coefficients. In addition, electron transport and heating will be correlated with measured MHD mode activity. Temperature and density measurements during multi-pulse coaxial gun-current operation will also be presented. * Work performed under the auspices of the US DOE by University of California Lawrence Livermore National Laboratory under contract W--7405--ENG--48.

Hudson, B. F.; Casper, T. A.; Hooper, E. B.; Jayakumar, R. J.; Lodestro, L. L.; McLean, H. S.; Moller, J. M.; Romero-Talamas, C. A.; Wood, R. D.

2007-11-01

122

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

SciTech Connect

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.

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

123

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

SciTech Connect

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 and examples of the most frequently implemented TCMs; institutional guidance such as assessing feasibility, agency responsibilities, and funding; and techniques for monitoring and enforcing TCMs. In addition, the document describes the tools available for evaluating TCM impacts on hydrocarbons, nitrogen oxides, and carbon monoxide emissions. Appendices present approaches to estimate TCM effects on PM-10 emissions; important sources of additional information; implementation experiences in various cities; and rules of thumb to quantitatively evaluate TCM transportation system effects. The information presented demonstrates that there have been significant advances in TCM development over the past decade, and that TCMs are appropriate control options for state implementation plans.

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

1990-09-01

124

Comparison of low Reynolds number k– ? models in simulation of momentum and heat transport under high free stream turbulence  

Microsoft Academic Search

Calculations of the effects of high free stream turbulence (FST) on the transport of momentum and heat in a flat plate turbulent boundary layer are presented. Four well known low Reynolds number k–? models namely Launder–Sharma, K.-Y. Chien, Lam–Bremhorst and Jones–Launder were used in order to investigate specifically their prediction capabilities under high FST conditions (initial FST intensity, Tui >

Ganesh R. Iyer; Savash Yavuzkurt

1999-01-01

125

Electrical transport measurements of a carbon-black-polymer composite  

NASA Astrophysics Data System (ADS)

I have measured simultaneously the resistance and linear expansion of a disordered carbon-black-polymer composite as a function of temperature from 25°C to 180°C. Both the sample resistance and thickness increase monotonically as a function of temperature, with precipitous increases at the polymer melt temperature. The resistance vs. thickness data increase monotonically with no precipitous increases. These results suggest that the electrical conduction mechanism is the same below, during, and above the polymer melt temperature. I have also measured the DC resistivity of these composites as a function of carbon-black concentration at room temperature. The data can be fit to a scaling law, yielding a conductivity critical exponent t = 2.9 +/- 0.1. This value agrees well with the theoretical mean-field value t = 3. This result suggests that the electrical transport is governed by mean-field behavior.

Heaney, Michael B.

1997-02-01

126

Direct measurements of transport properties are essential for site characterization  

SciTech Connect

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

Wright, J. [Pacific Northwest Lab., Richland, WA (United States); Conca, J.L. [Washington State Univ. Tri-Cities, Richland, WA (United States). Environmental Sciences

1994-08-01

127

Local measurements of turbulent angular momentum transport in circular Couette flow  

NASA Astrophysics Data System (ADS)

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.

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

2010-05-01

128

USE OF NEAR-SURFACE TDR MEASUREMENTS TO PREDICT SUBSURFACE SOLUTE TRANSPORT  

Technology Transfer Automated Retrieval System (TEKTRAN)

Successful prediction of the fate and transport of solutes requires accurate transport parameters. We attempt to determine near-surface chemical transport properties and evaluate whether the shallow measurements can be used to predict solute transport in the soil profile. The field TDR (time domai...

129

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

NASA Astrophysics Data System (ADS)

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

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

2011-12-01

130

Measurements of air pollution emission factors for marine transportation  

NASA Astrophysics Data System (ADS)

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

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

2012-12-01

131

Entanglement and Sensitivity in Precision Measurements with States of a Fluctuating Number of Particles  

SciTech Connect

The concepts of separability, entanglement, spin squeezing, and the Heisenberg limit are central in the theory of quantum-enhanced metrology. In the current literature, these are well established only in the case of linear interferometers operating with input quantum states of a known fixed number of particles. This manuscript generalizes these concepts and extends the quantum phase estimation theory by taking into account classical and quantum fluctuations of the particle number. Our analysis concerns most of the current experiments on precision measurements where the number of particles is known only on average.

Hyllus, P.; Smerzi, A. [INO-CNR BEC Center and Dipartimento di Fisica, Universita di Trento, I-38123 Povo (Italy); Pezze, L. [Laboratoire Charles Fabry de l'Institut d'Optique, CNRS and Univ. Paris-Sud, Campus Polytechnique, RD 128, F-91127 Palaiseau cedex (France)

2010-09-17

132

Network-based Accessibility Measures for Vulnerability Analysis of Degradable Transportation Networks  

Microsoft Academic Search

Accessibility is a fundamental concept in transportation analysis and urban planning. Typically, accessibility refers to the ‘ease’ of reaching opportunities for activities and services and can be used to assess the performance of a transportation and urban system. In this paper, we present network-based accessibility measures for assessing vulnerability of degradable transportation networks. The network-based accessibility measures consider the consequence

Anthony Chen; Chao Yang; Sirisak Kongsomsaksakul; Ming Lee

2007-01-01

133

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

Microsoft Academic Search

Emission factors for black carbon (BC) and particle number (PN) were measured from 226 individual heavy-duty (HD) diesel-fueled trucks driving through a 1 km-long California highway tunnel in August 2006. Emission factors were based on concurrent increases in BC, PN, and COB concentrations (measured at 1 Hz) that corresponded to the passage of individual HD trucks. The distributions of BC

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

2009-01-01

134

Velocity measurements in a high-Reynolds-number, momentum-conserving, axisymmetric, turbulent jet  

Microsoft Academic Search

The turbulent flow resulting from a top-hat jet exhausting into a large room was investigated. The Reynolds number based on exit conditions was approximately 10(exp 5). Velocity moments to third order were obtained using flying and stationary hot-wire and burst-mode laser-Doppler anemometry (LDA) techniques. The entire room was fully seeded for the LDA measurements. The measurements are shown to satisfy

Hussein J. Hussein; Steven P. Capp; William K. George

1994-01-01

135

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

NASA Astrophysics Data System (ADS)

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

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

2010-05-01

136

Practical quantum random number generator based on measuring the shot noise of vacuum states  

NASA Astrophysics Data System (ADS)

The shot noise of vacuum states is a kind of quantum noise and is totally random. In this paper a nondeterministic random number generation scheme based on measuring the shot noise of vacuum states is presented and experimentally demonstrated. We use a homodyne detector to measure the shot noise of vacuum states. Considering that the frequency bandwidth of our detector is limited, we derive the optimal sampling rate so that sampling points have the least correlation with each other. We also choose a method to extract random numbers from sampling values, and prove that the influence of classical noise can be avoided with this method so that the detector does not have to be shot-noise limited. The random numbers generated with this scheme have passed ent and diehard tests.

Shen, Yong; Tian, Liang; Zou, Hongxin

2010-06-01

137

Nonlinear Engine Component Fault Diagnosis From a Limited Number of Measurements Using a Combinatorial Approach  

Microsoft Academic Search

A method for diagnosing component faults of jet engines is presented. It uses nonlinear gas path analysis techniques to determine the values of health parameters, with the help of a suitably formulated engine simulation model. The incentive of the method is to achieve the determination of the values of component health indices when a limited number of measured quantities is

A. Stamatis; K. Mathioudakis

2003-01-01

138

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

ERIC Educational Resources Information Center

|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

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

2012-01-01

139

Microphysical and turbulent measurements of the Schmidt number in the vicinity of polar mesosphere summer echoes  

NASA Astrophysics Data System (ADS)

During the ECHO campaign in 1994 neutral and electron density fluctuations were measured together with charged aerosols on the same sounding rocket launched close to a VHF radar detecting polar mesosphere summer echoes (PMSE). For the first time this combination of measurements allows for an independent test of the microphysical and the turbulence interpretations of the Schmidt number (Sc). The Schmidt number characterizes the reduction of the electron diffusivity by charged aerosols, which leads to an enhancement of the electron density fluctuations at small spatial scales. In one of the flights charged aerosols were observed at ˜83-89km together with correlated depletions in electron density (‘biteouts’). We have applied a model of aerosol charging to the measured plasma profiles and determined a mean aerosol radius of ˜8nm and a mean aerosol charge of 1e-. In the microphysical description of electron diffusion these parameters correspond to Sc˜420. Spectral analysis of the electron density fluctuations showed enhancements of spectral densities at small scales suggesting likewise a Schmidt number much larger than unity. Using an energy dissipation rate of 67mW/kg as derived from neutral air turbulence measurements on the same rocket we get from the electron spectra Sc=385 which is in excellent agreement with the microphysical result. Apart from this turbulent layer we observe no significant disturbances in neutral air number densities below ˜87km which confirms earlier indications that processes must exist to create PMSEs which are not directly coupled to neutral air turbulence.

Lübken, Franz-Josef; Rapp, Markus; Blix, Tom; Thrane, Eivind

140

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

ERIC Educational Resources Information Center

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

Rapoport, Amnon

141

An Evaluation of Promotional Tactics and Utility Measurement Methods for Public Transportation Systems.  

National Technical Information Service (NTIS)

The report summarizes work in the third year of a research program that has sought to build on community-researched transportation needs and measure the impact of various marketing strategies for public transportation under carefully controlled conditions...

M. Alpert L. Golden J. Betak J. Story C. S. Davies

1977-01-01

142

Bureau of Transportation Statistics Issue Brief: Airline Travel Since 9/11. Number 13.  

National Technical Information Service (NTIS)

Todays airline industry presents a different picture than it did prior to the events of September 11, 2001 (9/11), with more passengers flying low-cost carriers, fewer empty seats, and a smaller workforce. Airline passenger travel and capacity (measured i...

2005-01-01

143

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

NASA Astrophysics Data System (ADS)

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

Lamminen, Erkki

2011-07-01

144

Feasibility of moiré deflectometry for measuring temperature and electron number density of rocket exhaust plume  

NASA Astrophysics Data System (ADS)

In this research, the feasibility of moiré deflectometry for diagnosing the temperature and the electron number density of rocket exhaust plume is studied. The dependence of the refractive index on the temperature, the pressure, the composition and the probe wavelength is established firstly. Based on which, the theoretical analysis and discussion indicate that it is impossible to achieve the measurement of the electron number density by both one- and two-wavelength moiré deflectometry in the given temperature, pressure and probe wavelength regions. Yet, it may be feasible to measure the temperature distribution of rocket exhaust plume by moiré deflectometry, if the imprecision of the temperature reconstruction is permitted by the practical measuring requirement.

Chen, Yun-Yun; Song, Yang; Li, Zhen-Hua; He, An-Zhi

2010-11-01

145

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

SciTech Connect

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.

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

1994-12-01

146

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

PubMed

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

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

2011-01-28

147

A hybrid Laplace transform finite analytic method for solving transport problems with large Peclet and Courant numbers  

NASA Astrophysics Data System (ADS)

In this study, the authors develop a hybrid Laplace transform finite analytic method (LTFAM) to solve the advection-dispersion equations with large Peclet and Courant numbers. The finite analytic method with a hybrid Laplace transform can incorporate the temporal variable into the numerical scheme and effectively control the numerical dispersion and oscillation at solute sharp fronts. Since the conventional numerical methods use a large amount of time steps to iterate to the specified time, they may lead to an accumulation of computation errors from each iteration step. Instead of using many fine time steps to satisfy the condition of Courant numbers less than 1 for the conventional numerical methods, the LTFAM algorithm uses a one-step approach to compute the solute concentrations at any specified time with stable numerical solutions. The derived LTFAM algorithm is verified with two numerical simulation examples against the analytical solutions. The numerical results of the LTFAM match the analytical solutions very well, especially for solute transport in the advection-dominated cases. The developed algorithm in this paper can save a large amount of simulating time and improve the computational accuracy. Furthermore, because the solutions of the LTFAM for a set of specified times can be obtained separately in the Laplace space, independence of each time step implies that the LTFAM is well-suited for executing on high performance parallel computers. This algorithm facilitates the long-term predictions of contaminant transport in the kilometer-scale field sites.

Wang, Wenke; Dai, Zhenxue; Li, Junting; Zhou, Liling

2012-12-01

148

Simulated and Measured Electron Thermal Transport with Varying Stochasticity in the MST RFP  

NASA Astrophysics Data System (ADS)

Recent results show that the MST RFP exhibits Rechester-Rosenbluth thermal transport only at the sawtooth crash, when the MHD activity peaks. This is in contrast with previous results [Biewer, 2003], which suggested stochastic transport between sawteeth. Results from a new set of first principles simulations using the resistive MHD code DEBS will be presented. The simulations are designed to match experimental conditions as closely as possible. Both Spitzer and neoclassical resistivity models were tried for the case of a fixed, experimentally measured resistivity at a central Lundquist number of 3.8x10^6. The measured electron thermal diffusion, ?e, obtained through power balance is compared to the Rechester-Rosenbluth electron thermal diffusion obtained from DEBS, ?RR = vTe ?Leff b^2/B^2, and the expected thermal diffusion from the field line tracing code MAgnetic Lines (MAL), ?MAL=vTeDmag where Dmag=(?r)^2/(2?l), where the traced magnetic field is also from DEBS. ?RR is generally found to be an order of magnitude larger than ?e except at the sawtooth crash, where the two are in agreement, suggesting that while magnetic fluctuations are always the dominant transport mechanism, the magnetic field is only fully stochastic at the sawtooth crash. This work is supported by the U.S. DOE.

Reusch, J. A.; Anderson, J. K.; den Hartog, D. J.; Ebrahimi, F.; Forest, C. B.; O'Connell, R.; Schnack, D. D.; Stephens, H. D.

2009-11-01

149

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

NASA Astrophysics Data System (ADS)

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

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

2010-05-01

150

Chloride transport across placental microvillous membranes measured by fluorescence  

SciTech Connect

Chloride transport across human placental microvillous vesicle membrane was investigated using the fluorescent probe SPQ (6-methoxy-N(3-sulfopropyl)quinolinium). Chloride influx (J{sub Cl}) was calculated from the initial rate of quenching of intravesicular SPQ fluorescence by chloride. J{sub Cl} measured by SPQ fluorescence was not significantly different from J{sub Cl} measured by uptake of {sup 36}Cl; SPQ did not affect measurements of J{sub Cl}. J{sub Cl} was increased 51% by a 58-mV membrane potential. Voltage-stimulated J{sub Cl} showed a saturable dependence on chloride concentration with a dissociation constant (K{sub d}) of 18 {plus minus} 5 mM and was inhibited by diphenylamine-2-carboxylate with an apparent inhibitory constant of 0.13 {plus minus} 0.03 mM. The activation energy calculated for voltage-stimulated J{sub Cl} was 4.6 {plus minus} 0.6 kcal/mol. J{sub Cl} was also stimulated by a reduction in the external pH from 7.0 to 5.5 (internal pH = 70). pH-stimulated chloride influx was increased by trans-HCO{sub 3} and was inhibited by dihydro-4,4{prime}-diisothiocyano-2,2{prime}-disulfonic stilbene. Uptake of {sup 36}Cl into microvillous vesicles was stimulated by trans-Cl. pH-stimulated J{sub Cl} showed a saturable dependence on chloride with a K{sub d} of 38 {plus minus} 6 mM but was not affected by membrane potential. No evidence was found for Na- or K-coupled chloride cotransport. These findings demonstrate the presence of a saturable chloride conductance and an electroneutral chloride-bicarbonate exchanger in the placental microvillous membrane.

Illsley, N.P.; Glaubensklee, C.; Davis, B.; Verkman, A.S. (Univ. of California, San Francisco (USA))

1988-12-01

151

Entanglement quantification from incomplete measurements: applications using photon-number-resolving weak homodyne detectors  

NASA Astrophysics Data System (ADS)

The certificate of success for a number of important quantum information processing protocols, such as entanglement distillation, is based on the difference in the entanglement content of the system quantum states before and after the protocol. In such cases, effective bounds need to be placed on the entanglement of non-local states consistent with statistics obtained from local measurements. In this paper, we study numerically the ability of a hybrid homodyne detector that combines phase sensitivity and photon-number resolution to set accurate bounds on the entanglement content of two-mode quadrature squeezed states without the need for full state tomography. We show that it is possible to set tight lower bounds on the entanglement of a family of two-mode degaussified states using only a few measurements. This presents a significant improvement over the resource requirements for the experimental demonstration of continuous-variable entanglement distillation, which traditionally relies on full quantum state tomography.

Puentes, Graciana; Datta, Animesh; Feito, Alvaro; Eisert, Jens; Plenio, Martin B.; Walmsley, Ian A.

2010-03-01

152

In situ measurements of effective diameter and effective droplet number concentration  

NASA Astrophysics Data System (ADS)

The effective diameter of cloud droplets is usually derived from measurements of droplet size distribution measured by Particle Measuring Systems (PMS) probes. The disadvantage of this method is that PMS probes have a truncated size range. During the RACE project, an alternative method to measure the effective diameter used a cloud extinction meter and King and Nevzorov hot wire liquid water content and total water content (LWC/TWC) probes installed on the National Research Council (NRC) Twin Otter. The effective diameter was derived from direct in situ measurements of the extinction coefficient (?) and liquid water content (W) as Deff=k1W/?. This method of calculation of Deff is free of problems related to deriving Deff from the truncated particle size distribution. Since measurements of ? and W cover the whole size range of cloud particles, this method gives an accurate value of Deff. This method can also be successfully applied for mixed and ice phase clouds, since the Nevzorov TWC probe provides measurements of total (ice plus liquid) water content. Effective number concentration was calculated as Neff = k2?3/W2. Comparisons of Deff and Neff, calculated by this method, and directly from PMS Forward Scattering Spectrometer Probe (FSSP) spectra, are favorable in the subset of conditions when the FSSP is considered to measure the spectra fully and accurately.

Korolev, Alexei V.; Isaac, George A.; Strapp, J. Walter; Nevzorov, Anatoly N.

1999-02-01

153

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

PubMed Central

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.

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

2012-01-01

154

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

PubMed

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

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

2012-02-28

155

Simultaneous velocity and passive scalar concentration measurements in low Reynolds number neutrally buoyant turbulent round jets  

Microsoft Academic Search

Velocity and scalar concentration characteristics of low Reynolds number (Re) neutrally buoyant turbulent round jets were studied using coupled particle image velocimetry and laser induced fluorescence.\\u000a Experiments were conducted on a jet with a fully developed pipe exit profile at Re = 1,500 and Re = 4,000. Measurements were made in the far field (60 x\\/D Re and the virtual origin is located far from the

G. A. Zarruk; E. A. Cowen

2008-01-01

156

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

Microsoft Academic Search

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

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

2012-01-01

157

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

Microsoft Academic Search

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

Elena Lopez

2005-01-01

158

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

Microsoft Academic Search

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

Dieter Rickenmann; Jens Turowski; Ramon Hegglin; Bruno Fritschi

2010-01-01

159

Direct Measurements of the Outer Membrane Stage of Ferric Enterobactin Transport  

PubMed Central

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

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

2010-01-01

160

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

SciTech Connect

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

Ma, Y.; Doyle, M.; Doeff, M.M.; De Jonghe, L.C.; Newman, J. [Lawrence Berkeley Lab., CA (United States); Fuller, T.F. [International Fuel Cells, South Windsor, CT (United States)

1995-06-01

161

Fuel Conservation Measures: The Transportation Sector. Volume II. Final Report.  

National Technical Information Service (NTIS)

The transportation sector accounts for 25 percent of the energy consumed in the United States and 18 percent of the energy consumed in Texas. Energy consumption in Texas represents 8.9 percent of national consumption. Of the energy used by transportation ...

R. Holder

1975-01-01

162

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

NASA Astrophysics Data System (ADS)

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

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

2013-04-01

163

Comparing Numbers of Drinks: College Students' Reports From Retrospective Summary, Followback, and Prospective Daily Diary Measures*  

PubMed Central

Objective: Retrospective summary, followback (retrospective diaries), and prospective daily diary measures of alcohol use among college students were compared across 29 days. Method: Participants were college students (n = 176; 60.2% female). Similarities in the three web-based reporting methods and both between-persons (i.e., gender, past drinking behavior, fraternity/sorority affiliation, average drinking behavior during the study period) and within-person (i.e., daily number of drinks, weekend days, Halloween, and week of study) predictors of concordance between reports of followback and prospective diaries were analyzed. Results: On prospective diaries, students reported a greater number of maximum drinks (compared with followback only) and a greater number of heavy drinking days in the past 2 weeks (compared with both followback and retrospective summary measures). In followback compared with prospective diaries, students tended to provide inflated accounts of their drinking behavior when reporting about occasions with greater typical drinking (i.e., weekends, Halloween) and deflated accounts of their drinking on their own heavier drinking days, especially if they were affiliated with a fraternity/sorority. Women and students who drank more on average across study days tended to provide deflated estimates of their day-to-day drinking in followback compared with prospective diary. Conclusions: Understanding the concordance and discordance in self-reported alcohol use is an important area for continued research efforts.

Patrick, Megan E.; Lee, Christine M.

2010-01-01

164

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

SciTech Connect

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.

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

165

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

NASA Astrophysics Data System (ADS)

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

Šaši?, O.; de Urquijo, J.; Juárez, A. M.; Dupljanin, S.; Jovanovi?, J.; Hernández-Ávila, J. L.; Basurto, E.; Petrovi?, Z. Lj

2010-06-01

166

Fuel conservation measures: the transportation sector. Volume II. Final report  

Microsoft Academic Search

The transportation sector accounts for 25 percent of the energy consumed in the United States and 18 percent of the energy consumed in Texas. Energy consumption in Texas represents 8.9 percent of national consumption. Of the energy used by transportation in the United States, 6.2 percent is consumed in Texas. Over 7.3 billion gallons of fuel were consumed by the

Holder

1975-01-01

167

A Simulation Study to Evaluate the Impact of the Number of Lesions Measured on Response Assessment  

PubMed Central

The objectives of this study were to evaluate whether the number of lesions that are used to measure tumor burden affects response assessment and inter-rater variability. In order to accomplish this, a simulation study was conducted. Data were generated from a mixed-effects mixture model. Parameter values to input in the model were obtained from analysis of real data. Response assessments based on ten, five, three, two, and one lesion were evaluated. There was little difference between response assessments based on five lesions and response assessments based on ten lesions. When fewer than five lesions were used to assess response, there were notable differences from the ten-lesion based response assessment. Basing response assessment on a small number of lesions tends to overestimate response rates and lead to misclassification of patients’ response status. Therefore, measuring five lesions per patient appears to sufficiently capture patients’ response to therapy. Measuring fewer than five lesions results in loss of information that may adversely affect clinical trial results as well as patient management.

Moskowitz, Chaya S.; Jia, Xiaoyu; Schwartz, Lawrence H.; Gonen, Mithat

2009-01-01

168

Particle number to volume concentration ratios at two measurement sites in Finland  

NASA Astrophysics Data System (ADS)

Past studies have indicated that the aerosol number to volume concentration ratio R, defined as the number concentration of particles larger than a certain cutoff diameter divided by the total particle volume concentration, shows little variability in marine conditions. In this study, aerosol number size distributions from Pallas in northern Finland and from the island of Utö in the Baltic Sea, representing more continental aerosol systems, were analyzed. The data set covered continuous measurements for 20 months at Pallas and 21 months at Utö. The average value and standard deviation of R, calculated from the measured data, were found to be inversely dependent on the cutoff diameter used, dc. The average value of R (in ?m-3) could be expressed as R(dc) = 22,000 × dc-1 + 20 (where dc is in nm) in Pallas and R(dc) = 40,000 × dc-1 - 160 in Utö in dc range 50-200 nm. Also, the relative deviation (standard deviation divided by average value) of R(dc) was found to be dependent on the cutoff diameter. A clear seasonal pattern of the values of R was observed at both sites, and this was found to be related to ambient temperature. The value of R was found to depend on the air mass type at Pallas, but at Utö such dependency was not observed. Besides temperature, R was also analyzed against several meteorological parameters, including global solar radiation, air pressure, relative humidity, and rain. The found dependencies between the number of potential cloud condensation nuclei and particle volume concentration provide tools for developing more accurate empirical parameterizations describing cloud formation in large-scale atmospheric models.

KivekäS, Niku; Kerminen, Veli-Matti; Engler, Christa; Lihavainen, Heikki; Komppula, Mika; Viisanen, Yrjö; Kulmala, Markku

2007-02-01

169

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

SciTech Connect

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

Higgins, Matthew B.

2005-01-01

170

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

NASA Astrophysics Data System (ADS)

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.

Mteri, Hassan H.

171

Improvement of Pulping Uniformity by Measurement of Single Fiber Kappa Number  

SciTech Connect

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.

Richard R. Gustafson; James B. Callis

2001-11-20

172

Generating conditional atomic entanglement by measuring photon number in a single output channel  

SciTech Connect

The polarization analysis of quantized probe light transmitted through an atomic ensemble has been used to prepare entangled collective atomic states. In a 'balanced' detection configuration, where the difference signal from two detection ports is analyzed, the continuous monitoring of a component of the Stokes field vector provides a means for conditional projective measurements on the atomic system. Here, we make use of classical driving fields, in the pulsed regime, and of an 'unbalanced' detection setup (single detector) where the effective photon number of scattered photons is the detected observable. Conditional atomic spin squeezed states and superpositions of such squeezed states can be prepared in this manner.

Genes, C.; Berman, P. R. [Michigan Center for Theoretical Physics, FOCUS Center, and Physics Department, University of Michigan, Ann Arbor, Michigan 48109-1040 (United States)

2006-01-15

173

Cryptographic random number generators for low-power distributed measurement system  

NASA Astrophysics Data System (ADS)

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

Czernik, Pawel; Olszyna, Jakub

2009-06-01

174

Measuring substance velocity in zone of gravitational turbulent gas mixing at low Reynolds numbers  

NASA Astrophysics Data System (ADS)

We have measured the distribution of the velocity of a tracking substance in the zone of the gravitational turbulent mixing of two gases with different densities, which is caused by the development of Rayleigh-Taylor instability in the gravitational field. The velocity field has been studied using a single-component laser Doppler anemometer, which allowed the temporal variation of the moduli of vertical and horizontal components of the tracking substance velocity projection to be determined in unstable mixing systems with the Atwood numbers of 0.23 and 0.83.

Pavlenko, A. V.; Tyaktev, A. A.; Bugaenko, I. L.

2011-06-01

175

Laboratory measurements of the transport of radon gas through concrete samples  

Microsoft Academic Search

Experiments were conducted to measure the transportability of radon gas through common concrete samples which were characterized by their mix proportions, dimensions, porosity, air permeability, and radon gas diffusion coefficient. Several innovative test systems and methods were designed, fabricated, and calibrated to accurately measure these radon gas transport characteristics for concrete and to overcome many of the shortcomings of previously

Kevin J. Renken; Timothy Rosenberg

1995-01-01

176

Aerosol Measurements From Recent Alaskan Volcanic Eruptions: Implications for Volcanic Ash Transport Predictions  

Microsoft Academic Search

Size and time-resolved aerosol compositional measurements conducted during the 2006 Augustine Volcano and 2007 Pavlof Volcano eruptions provide ground-truth information for use in the validation of volcanic ash transport models. These measurements provide quantitative information on the size and concentration of the aerosol, which can be used to test the volcanic aerosol source profiles and transport characteristics used in volcanic

C. F. Cahill; P. G. Rinkleff; J. Dehn; P. Webley; T. A. Cahill; D. E. Barnes

2007-01-01

177

Design and measurement considerations of hairpin resonator probes for determining electron number density in collisional plasmas  

NASA Astrophysics Data System (ADS)

The hairpin resonator probe has been developed in recent years into a sophisticated diagnostic technique capable of measuring spatially resolved electron number densities in sub-Torr discharges. In this paper, we extend the use of this technique to discharges at pressures greater than 1 Torr. In this regime, the effects of electron-neutral collisions become significant and a suitable correction is applied in conjunction with the sheath correction. We also describe elements of hairpin design and coupling that need to be more carefully controlled in order to maximize the range of electron densities that can be detected at higher pressures. Finally, we discuss limitations to the transmission-line model used routinely to interpret hairpin data as they apply to measurements in a nonuniform plasma.

Sands, Brian L.; Siefert, Nicholas S.; Ganguly, Biswa N.

2007-11-01

178

A LabVIEW ® program for determining electron number density from Stark broadening measurements of the hydrogen-beta line  

Microsoft Academic Search

A useful plasma diagnostic is the measurement of electron number density. One way to accomplish such measurements is to determine the contribution to the broadening of a spectral line due to the Stark effect. To simplify and extend such electron density measurements across computer platforms, a program that calculates electron number density from the Stark-broadened hydrogen-beta line has been written

Timothy K. Starn; Norman N. Sesi; Julie A. Horner; Gary M. Hieftje

1995-01-01

179

Measurement of spatio-temporal transport in live cells  

NASA Astrophysics Data System (ADS)

The live cell is a highly dynamical system with complicated biophysical and biochemical processes taking place at diverse spatiotemporal scales. Though it is well known that microtubules and actin filaments play important roles in intracellular transport, their dynamic behavior is not entirely understood. We propose a unified approach to studying transport in live cells. We used Spatial Light Interference Microscopy, a quantitative phase imaging method developed in our laboratory, to extract cell mass distributions over broad spatiotemporal scales. The dispersion relations for this transport dynamics, i.e. frequency bandwidth vs. spatial frequencies, reveal deterministic mass transport at large spatial scales (w˜q) and diffusive transport at small spatial scales (w˜q?2). At submicron scales, we observed a w˜q?3 behavior, which indicates whip-like movements of protein filaments. Further control experiments where both the microtubule and actin polymerization were blocked suggests that essentially actin governs the long spatial scales behavior and microtubules the short scales. This label-free method enables us to access different components of cell dynamics and quantify diffusion coefficients and speed of motor proteins.

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

2010-03-01

180

Dynamics of dispersive photon-number QND measurements in a micromaser  

SciTech Connect

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.

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

2007-04-15

181

Active Transportation Measurement and Benchmarking Development: New Orleans State of Active Transportation Report 2010, Part 1.  

National Technical Information Service (NTIS)

Over the last decade, there has been a surge in bicycle and pedestrian use in communities that have invested in active transportation infrastructure and programming. While these increases show potentially promising trends, many of the cities that have sho...

B. Fields

2012-01-01

182

Performance measurement in the transportation and distribution sector  

Microsoft Academic Search

In the transportation and distribution (T&D) sector, as in many others, it is important to have a good performance in operations. In order to achieve high performance, it is necessary to know which operational factors are critical for success and which are less important. Only then can management focus attention on those factors that have a strong effect on performance.

Karel van Donselaar; Kees Kokke; Martijn Allessie

1998-01-01

183

The Impact of the Turing Number on Quantitative ASAXS Measurements of Ternary Alloys  

NASA Astrophysics Data System (ADS)

During the last ten years, anomalous small-angle x-ray scattering (ASAXS) became a precise quantitative method resolving scattering contributions two or three orders of magnitude smaller compared with the overall small-angle scattering, which are related to the so-called pure-resonant scattering contribution. The technique gives access to the analysis of weak concentration fluctuations in systems undergoing spinodal decomposition, which cannot be resolved by transmission electron microscopy (TEM) images because these systems are to a large degree homogeneous. In addition to the structural information, precise quantitative information about the different chemical concentrations localized in the nanosized structures of ternary alloys are obtained from these scattering contributions. The application of the Gauss elimination algorithm to the vector equation established by ASAXS measurements at three x-ray energies is demonstrated for two ternary alloys, one in the state of spinodal decomposition. The example deals with the quantitative analysis of the resonant invariant (RI-analysis). From the integrals of the pure-resonant scattering contribution, the chemical concentrations in the nanoscaled phases are determined. Moreover the Turing numbers of the vector equation stated by the ASAXS measurement are calculated giving a decisive quantitative measure thereby indicating whether the quantitative parameters obtained from the matrix inversion are significant.

Goerigk, Günter Johannes

2013-01-01

184

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

NASA Astrophysics Data System (ADS)

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.

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

2010-05-01

185

Measuring effective radium concentration with large numbers of samples. Part II--general properties and representativity.  

PubMed

Effective radium concentration EC(Ra), product of radium concentration and radon emanation, is the source term for radon release into the pore space of rocks and the environment. Over a period of three years, we performed more than 6000 radon-222 accumulation experiments in the laboratory with scintillation flasks and SSNTDs and we obtained experimental EC(Ra) values from more than 1570 rock and soil samples. With this method, which allowed the measurement of EC(Ra) from large numbers of samples with sufficient accuracy and uncertainty, as detailed in the companion paper, the dependence of the emanation factor on temperature and moisture content is revisited. In addition, with such a large EC(Ra) dataset, dispersion of EC(Ra) can be studied at sample-scale (cm to dm) and at scarp-scale (m to tens of m). Furthermore, we are able to discuss the representativity of obtained EC(Ra) values at field-scale, and to investigate the spatial variations of EC(Ra) over kilometric scales, within geological formations and across formations and faults. This experimental study opens new perspectives in the understanding of radium geochemistry and illustrates the importance of studying the radon source term with large numbers of samples for the modelling of geological and environmental processes, and also for the assessment of the radon health hazard. PMID:22819630

Girault, Frédéric; Perrier, Frédéric

2012-07-20

186

Time-resolving electron energy analyzer measurements of intense relativistic beam transport  

Microsoft Academic Search

Summary form only given. A time-resolving electron energy (TREE) analyzer has been used to measure a 2-MeV, 20-ns intense relativistic electron beam. Time-resolved energy measurements have been taken immediately downstream of the diode and after a transport region. This provides direct experimental measurement of the effect of the transport region on beam energy and pulse shape. The TREE analyzer consists

D. J. Weidman; M. J. Rhee; R. F. Schneider

1990-01-01

187

Multipoint incremental motor unit number estimation as an outcome measure in ALS  

PubMed Central

Background: Improved outcome measures are necessary to reduce sample size and increase power in amyotrophic lateral sclerosis (ALS) clinical trials. Motor unit number estimation (MUNE) is a potentially attractive tool. MUNE methods previously employed in multicenter trials exhibited excessive variability and were prone to artifact. Objective: To evaluate a modification of standard incremental MUNE in a multicenter natural history study of subjects with ALS. Methods: Fifty healthy subjects were evaluated twice and 71 subjects with ALS were studied repeatedly for up to 500 days. Side and nerve studied was based on clinical examination findings. Nerves were stimulated at 3 specified locations and 3 increments were obtained at each location. Average single motor unit action potential (SMUP) amplitude was calculated by adding the amplitude of the third increment at each location and dividing by 9; SMUP was divided into maximum CMAP amplitude to determine the MUNE. Results: Test-retest variability was 9% in normal subjects. Average MUNE for normal subjects was 225 (±87), and was 41.9 (±39) among subjects with ALS at baseline. Subjects with ALS showed clear decrements over time, with an overage rate of decline of approximately 9% per month. SMUP amplitude increased with time in a fashion consistent with the known pathophysiology of ALS. Conclusion: Multipoint incremental MUNE has a number of attributes that make it attractive as an outcome measure in ALS and other diseases characterized by motor unit loss. It can be rapidly performed on any EMG machine and has repeatability and rates of decline that favorably compare to other previously described methods.

Watson, M.L.; Simionescu, L.; Caress, J.B.; Burns, T.M.; Maragakis, N.J.; Benatar, M.; David, W.S.; Sharma, K.R.; Rutkove, S.B.

2011-01-01

188

A Comparison of Coarse Bedload Transport Measured with Bedload Traps and Helley-Smith Samplers  

Microsoft Academic Search

Gravel bedload transport rates were measured at eight study sites in coarse-bedded Rocky Mountain streams using 4-6 bedload traps deployed across the stream width and a 76 by 76 mm opening Helley Smith sampler. Transport rates obtained from bedload traps increased steeply with flow which resulted in steep and well-defined transport rating curves with exponents of 8 to 16. Gravel

Kristin Bunte; Steven R. Abt; John P. Potyondy; Kurt W. Swingle

2008-01-01

189

Measurement of fusion boundary energy transport during Arc welding  

Microsoft Academic Search

An experimental technique is presented to identify fusion boundary (liquid\\/solid interface) energy transport mechanisms during welding procedures. The gas-tungsten-arc-spot-welding procedure, using a low melting (point specimen material (lead), was chosen to demonstrate the methods. Vaporization energy losses were found to be important during the growth of the fusion boundary. Significant thermal convection was absent within the weld pool for applied

C. S. Landram

1983-01-01

190

Transportable Distance Measurement System for Long-Range Applications  

Microsoft Academic Search

This paper describes a transportable distance mea- surement system based on synthetic wavelength interferometry using two frequency-doubled Nd:YAG lasers. To eliminate polar- ization crosstalk issue, a different system has been set up from those usually described in the literature. Indeed, we propose a system where the different beams are spatially separated instead of being polarization-separated. Furthermore, the superheterodyne detection is

Shéhérazade Azouigui; Thomas Badr; Jean-Pierre Wallerand; Marc Himbert; José-Antonio Salgado; Jean-Paul Senelaer; Frédéric Kwasnik; Patrick Juncar

2011-01-01

191

Transport measurements from in-service undersea telephone cables  

Microsoft Academic Search

The motion of the ocean through the Earth's magnetic field creates a cross-stream voltage proportional to the transport of the stream. These motion-induced voltages have been observed for more than ten years by the use of an abandoned cable spanning the Florida Current. In-service undersea telephone cables, including fiber optic cables with branch lines, can also be used to determine

Jimmy C. Larsen

1991-01-01

192

Evaluation and modeling of the size fractionated aerosol particle number concentration measurements nearby a major road in Helsinki - Part II: Aerosol measurements within the SAPPHIRE project  

Microsoft Academic Search

This study presents an evaluation and modeling exercise of the size fractionated aerosol particle number concentrations measured nearby a major road in Helsinki during 23 August-19 September 2003 and 14 January-11 February 2004. The available information also included electronic traffic counts, on-site meteorological measurements, and urban background particle number size distribution measurement. The ultrafine particle (UFP, diameter<100 nm) number concentrations

T. Hussein; J. Kukkonen; H. Korhonen; M. Pohjola; L. Pirjola; D. Wraith; J. Härkönen; K. Teinilä; I. K. Koponen; A. Karppinen; R. Hillamo; M. Kulmala

2007-01-01

193

A validation of eye movements as a measure of elementary school children's developing number sense  

Microsoft Academic Search

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 during task solution reflect children's use of the number

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

2008-01-01

194

Measuring effective radium concentration with large numbers of samples. Part I--experimental method and uncertainties.  

PubMed

Effective radium concentration EC(Ra), product of radium concentration and radon emanation, is the source term for radon release into the pore space of rocks and the environment. To measure EC(Ra), we have conducted, over a period of three years, more than 5500 radon-222 accumulation experiments in the laboratory with scintillation flasks, and about 700 with integrating solid state nuclear track detectors, leading to experimental values of EC(Ra) for more than 1570 rock and soil samples. Through detailed systematic checks and intercomparison between various repeated experiments, the experimental uncertainty has been assessed, and ranges from 30% (1 ?) for EC(Ra) values smaller than 0.2 Bq kg(-1) to about 8-10% for EC(Ra) values larger than 50 Bq kg(-1). The detection limit, defined as the 90% probability for obtaining a non-zero experimental EC(Ra) value at 68% confidence level, depends on the mass of the sample with respect to the volume of the accumulation volume, and typically varies between 0.04 and 0.09 Bq kg(-1). To measure EC(Ra) from large numbers of samples with sufficient accuracy and uncertainty for our purpose, i.e. for the most natural objects encountered in the environment, the accumulation method with scintillation flask emerged as particularly useful and robust. Properties of EC(Ra) and interpretations inferred from this large data set are presented in the companion paper. PMID:22819081

Girault, Frédéric; Perrier, Frédéric

2012-07-21

195

Turbulence Measurements of a High Reynolds Number Inclined Jet in Crossflow using PIV and FRAP  

NASA Astrophysics Data System (ADS)

The TKE, turbulence intensity and Reynolds shear stress for a jet inclined at 30^o to the freestream with a blowing ratio of 2 and Reynolds numbers, based on hole diameter, (Red) of 30000 are measured using 3-D Stereoscopic PIV and a miniature Fast Response Aerodynamic Probe (FRAP). The Maximum Entropy Method is used to compose a spectrum for variance calculations from PIV data, thereby ameliorating the low sampling rate and systematic noise. The PIV measurements are compared with those from the FRAP and found to be within error estimates. TKE contours indicate that the two main sites of turbulence production are the counter rotating vortex pair and the shearing surface of the jet. It is observed that the turbulence within the vortex pair is higher and dissipates slower than that in the jet shear surface. The eddy diffusivities of momentum in different cardinal directions are also compared and found to have an anistropic distribution. The mechanisms of turbulent mixing in this complex flow and their relevance to turbulence modeling are commented upon.

Aga, Vipluv; Feliciani, Claudio; Chokani, Ndaona; Abhari, Reza

2007-11-01

196

Supplemental Data Consequences of Motor Copy Number on the Intracellular Transport of Kinesin1Driven Lipid Droplets  

Microsoft Academic Search

We find that kinesin-1 is absolutely required for net plus-end transport of droplets and for motion of individual droplets. We performed four independent tests to distinguish if kinesin's role in droplet transport is direct or indirect. First, kinesin-1 is physically present on droplets. Second, acute inhibition of kinesin-1 with antibodies quickly abolishes net plus-end transport. Third, partially functional kinesin-1 results

George T. Shubeita; Susan L. Tran; Jing Xu; Michael Vershinin; Silvia Cermelli; Sean L. Cotton; Michael A. Welte; Steven P. Gross

197

Unified Measurement System with Suction Control for Gas Transport Parameters in Porous Media  

Microsoft Academic Search

Pore geometric parameters including pore size distribution, total and air-filled porosities, pore tortuosity and connectivity strongly influence air flow in porous media, and, thus, characterize gas transport parameters such as gas diffusion coefficient Dp and air permeability ka. In this study, the gas transport parameters were measured for porous media with varying textures under repeated drying and wetting cycles using

K. Kawamoto; M. A. Rouf; S. Hamamoto; T. Sakaki; T. Komatsu; P. Moldrup

2010-01-01

198

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

PubMed

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

Zadeh, L A

2001-04-01

199

Numerical Study of Flow Angles and Mach Number Measurement Using the Surface Pressure of a Supersonic Aircraft with Nose Cone  

NASA Astrophysics Data System (ADS)

Numerical simulation of the flow around an air data sensor (ADS), which measures flow angles and Mach numbers using surface pressures on a nose cone, was conducted in this study. Effects of the half-cone angle on the flow angle and Mach number measurements were investigated. Results show that a large half-cone angle achieves high sensitivity of flow angle measurements. Results further demonstrated that a small half-cone angle achieves high-sensitivity of Mach number measurements. To satisfy these conflicting requests, we proposed the use of bi-conic nose cones with two gradients. High sensitivity was achieved for both flow angle measurements and Mach number measurements using this bi-conic nose cone.

Fukiba, Katsuyoshi; Tsuboi, Nobuyuki; Kobayashi, Hiroaki

200

Direct Measurement of Fast Axonal Organelle Transport in the Sciatic Nerve of Rats Treated with Acrylamide.  

National Technical Information Service (NTIS)

The effects of acrylamide on fast axonal transport have been measured primarily using the indirect methods of isotope or enzyme accumulation. The authors report the first direct evaluation of the effects of subchronic acrylamide dosing (150, 300, or 500 m...

S. Padilla M. B. Atkinson A. C. Breuer

1993-01-01

201

Measurement of Phloem Transport Rates by an Indicator-Dilution Technique 1  

PubMed Central

An indicator-dilution technique for the measurement of flow rates, commonly used by animal physiologists for circulation measurements, was adapted to the measurement of phloem translocation rates in the wheat (Triticum aestivum L.) peduncle. The approach is based on the observation that, during the transport of a given amount of solute, its mean concentration will be inversely proportional to flow rate. For phloem transport in the wheat peduncle, the necessary measurements are (a) the time course of tracer kinetics in the peduncle phloem, (b) the volume of sieve tubes and companion cells in the monitored segment of the peduncle, and (c) the amount of tracer transported past that point. The method was evaluated by in situ monitoring of 32PO4 transport in pulse-labeling experiments. Specific activities (i.e.32P concentrations) of phloem exudate were in good agreement with those calculated from in situ count rates and measured phloem areas. Mass transport rates, calculated from volume flow rates and phloem exudate dry matter content, also agreed well with expected mass transport rates based on measurements of grain growth rate and net CO2 exchange by the ear. The indicator-dilution technique appears to offer good precision and accuracy for short-term measurements of phloem transport rates in the wheast peduncle and should be useful for other systems as well. In contrast to velocities based on time-delay measurements, it is more precise, more accurate, and produces an estimate of mean, rather than maximum, velocity. Also, since only a single detector is required, it can be applied to very short transport paths.

Fisher, Donald B.

1990-01-01

202

IL-7 addition increases spot size and number as measured by T-SPOT.TB (®).  

PubMed

The interferon-gamma (IFN-?) release assay (IGRA) is an in vitro extension of the century-old in vivo tuberculin skin test, better known as the TST. Shortcomings to the TST are multifactorial and include limitations in sensitivity and specificity. IGRAs improve diagnostic specificity by using antigens not found in the Bacille Calmette-Guérin, a vaccine given in most countries. IGRAs capture the IFN-? produced by T cells in response to antigen stimulation. The ELISPOT immediately captures IFN-? produced directly from each cell, resulting in the generation of a cellular "footprint." The dimensions and intensity of the generated footprint indicate the avidity of the secreting cell. We show a further improvement in IGRAs by addition of interleukin-7 (IL-7). IL-7 reduces T-cell apoptosis and stabilizes IFN-? message. In addition to increasing the number of spots in the ELISPOT T-SPOT.TB platform, IL-7 increased IFN-? production per cell as measured by an increase in spot size with no change in spot distribution. PMID:21956514

Feske, Marsha L; Medina, Miguel; Graviss, Edward A; Lewis, Dorothy E

2012-01-01

203

Mahler measure of the Horie unit and Weber's Class Number Problem in the Cyclotomic p-extension of  

NASA Astrophysics Data System (ADS)

Let p be a prime number. It is an interesting problem to consider whether a prime number l divides the class numbers of the intermediate fields of the cyclotomic p-extension of Q. In the case p = 2, R. Okazaki developed a theory for this problem by using Mahler measure. In this paper, we focus on the case p = 3 and show that a prime number l does not divide the class numbers of the intermediate fields of the cyclotomic 33-extension of if l satisfies l?+/-1 mod 27.

Morisawa, Takayuki

2010-07-01

204

Measurements of moisture transport in wood-based materials under ...  

Treesearch

Author: Glass, Samuel V. ... While many studies using common building materials have explored the ... In our experiments, water vapor permeance is measured by sealing a material between two chambers that are independently controlled; ...

205

TRANSPORT  

EPA Science Inventory

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

206

Measuring charge transport in a thin solid film using charge sensing.  

PubMed

We measure charge transport in a hydrogenated amorphous silicon (a-Si:H) thin film using a nanometer scale silicon MOSFET as a charge sensor. This charge detection technique makes possible the measurement of extremely large resistances even in the presence of blocking contacts. At high temperatures, where the resistance of the a-Si:H is not too large, the charge detection measurement agrees with a direct measurement of current. The device geometry allows us to probe both the field effect and dispersive transport in the a-Si:H using charge sensing and to extract the density of states near the Fermi energy. PMID:20178356

Maclean, Kenneth; Mentzel, Tamar S; Kastner, Marc A

2010-03-10

207

Transport and Raman measurements in Graphene: Interaction strength and scattering mechanisms  

NASA Astrophysics Data System (ADS)

Among the most common techniques for characterization of Graphene materials have been electronic transport and Raman measurements, for instance both can be easily tuned by changing the charge carrier density and electronic screening. In each situation the underlying physics is connected to the interactions and relaxation mechanisms in the material. However it is well known that the electronic scattering time does not necessarily describe the broadening observed in Raman measurements. Here we present micro Raman and transport measurements of single layer graphene field effect devices. We discuss interaction and scattering mechanisms and how these are connected in the different measurements.

Remi, Sebastian; Swan, Anna; Goldberg, Bennett

2013-03-01

208

41 CFR 102-118.170 - Will GSA continue to maintain a centralized numbering system for Government transportation...  

Code of Federal Regulations, 2013 CFR

...this system. Write to: General Services Administration Transportation Audit Division (QMCA) Crystal Plaza 4, Room 300 2200 Crystal Drive Arlington, VA 22202 www.gsa.gov/transaudits [65 FR 24569, Apr. 26, 2000,...

2013-01-01

209

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

Microsoft Academic Search

Quorum-sensing is the mechanism by which bacteria communicate and synchronize group behaviors. Quantitative information on parameters such as the copy number of particular quorum-sensing proteins should contribute strongly to understanding how the quorum-sensing network functions. Here, we show that the copy number of the master regulator protein LuxR in Vibrio harveyi can be determined in vivo by exploiting small-number fluctuations of

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

2010-01-01

210

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

SciTech Connect

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

Howard, N. T.; Greenwald, M.; White, A. E.; Reinke, M. L.; Ernst, D.; Podpaly, Y. [MIT-Plasma Science and Fusion Center, Cambridge, Massachusetts 02139 (United States); Mikkelsen, D. R. [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States); Candy, J. [General Atomics, San Diego, California 92186 (United States)

2012-05-15

211

Transportation  

Microsoft Academic Search

This paper presents a strategic-level examination of the transportation industry - an industry vital to national prosperity and security. Because the defense sector relies on commercial transportation for both peacetime activities and for power projection, senior military leaders must understand the global transportation industry and the environment in which the private sector operates. They must also assess the role of

Peter Hall; Mohammed Al-Adwan; Dennis M. Brogan; William J. Flannery; Gregory L. Gardner; Elizabeth J. Gilleo; Robert A. Hall; Peter C. Hunt; Nathan M. Kathir; Timothy M. McKeithen; Evan M. Miller; E. Mlikan; Ruben Perales; Lawrence J. Pleis; Paul M. Smith; Paul Needham; Steve Ditmeyer

1969-01-01

212

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

NASA Astrophysics Data System (ADS)

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

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

2010-08-01

213

Measurement and Analysis of the Noise Radiated by Low Mach Number Centrifugal Blowers.  

NASA Astrophysics Data System (ADS)

An investigation was performed of the broad band, aerodynamically generated noise in low tip-speed Mach number, centrifugal air moving devices. An interdisciplinary experimental approach was taken which involved investigation of the aerodynamic and acoustic fields, and their mutual relationship. The noise generation process was studied using two experimental vehicles: (1) a scale model of a homologous family of centrifugal blowers typical of those used to cool computer and business equipment, and (2) a single blade from a centrifugal blower impeller placed in a known, controllable flow field. The radiation characteristics of the model blower were investigated by measuring the acoustic intensity distribution near the blower inlet and comparing it with the intensity near the inlet to an axial flow fan. Results showed that the centrifugal blower is a distributed, random noise source, unlike an axial fan which exhibited the effects of a coherent, interacting source distribution. Aerodynamic studies of the flow field in the inlet and at the discharge to the rotating impeller were used to assess the mean flow distribution through the impeller blade channels and to identify regions of excessive turbulence near the rotating blade row. Both circumferential and spanwise mean flow nonuniformities were identified along with a region of increased turbulence just downstream of the scroll cutoff. The fluid incidence angle, normally taken as an indicator of blower performance, was estimated from mean flow data as deviating considerably from an ideal impeller design. An investigation of the noise radiated from the single, isolated airfoil was performed using modern correlation and spectral analysis techniques. Radiation from the single blade in flow was characterized using newly developed expressions for the correlation area and the dipole source strength per unit area, and from the relationship between the blade surface pressure and the incident turbulent flow field. Results showed that radiation from the single blade was dominated by the effects of the incident turbulence. Normalized correlations areas of approximately 25% were measured at low frequencies. While the noise generation was more efficient at the trailing edge of the isolated blade, more noise was radiated from the region near the leading edge.

Yeager, David Marvin

214

Pleural Transport Physiology: Insights from Biological Marker Measurements in Transudates  

PubMed Central

Aims: The aim of this study was to evaluate the physicochemical properties of the pleural mesothelial barrier and of the biological markers that facilitate or eliminate the passage of molecules through the pleura. Methods and Material: Pleural fluid samples from sixty-five patients with heart failure were analyzed. The biological markers studied were lactate dehydrogenase (LDH), adenosine deaminase (ADA), interleukin-6 (IL-6), C-reactive protein (CRP), tumor necrosis factor-? (TNF-?), carcinoembryonic antigen (CEA), copper/zinc superoxide dismutase (CuZnSOD), matrix metalloproteinase-2 (MMP-2), -3 (MMP-3), -7(MMP-7), -8 (MMP-8) and -9 (MMP-9). Based on the pleural fluid/serum ratio, these molecules were divided into three groups: a) the LDH-like group with a pleural fluid/serum ratio between 0,4 and 0,8 (LDH, CEA, CuZnSOD, ADA, CRP, MMP-8), b) molecules with a pleural fluid/serum ratio less than 0,4 (MMP-7 and MMP-9) and c) molecules with a pleural fluid/serum ratio equal or above 1 (TNF-?, IL-6, MMP-2 and MMP-3). Results: No correlation between the molecular radius and the pleural fluid to serum ratio of the above biological markers was found. Conclusions: The molecular size is not a major determinant for the passage of molecules through the mesothelial barrier. Several other factors may influence the transport of the above molecules to pleural cavity, such as their charge and shape.

Apostolidou, Eleni; Tsilioni, Irini; Hatzoglou, Chrissi; Molyvdas, Paschalis-Adam; Gourgoulianis I, Konstantinos

2011-01-01

215

Measuring performance of night-time interfacility transport service.  

PubMed

The service reorganization is a part of the healthcare system reform. Some hospitals may not be able to provide all services in a 24-h basis. This evaluation was on all night-time (22 : 00 p.m. to 07 : 00 a.m.) interfacility transport by Alice Ho Miu Ling Hospital emergency department from January 2008 to December 2010, which were in-patients from nonemergency wards. The safety, speed, and performance were analyzed. During the study period, 73 cases were transferred out. Majority of them were having neurosurgical emergency (n=21, 29%) or surgical emergency (n=34, 46%). En-route physiological deteriorations were encountered in 4% (3/73) of cases. The mean acceptance time was 8 min and the team mobilization time was 13 min on average. The total service time ranged from 40 to 115 min. In conclusion, en-route adverse event was not rare. The specialized team can act as a facilitator and coordinator to improve the safety and effectiveness of the whole process. PMID:22027654

Hui, Yuet Yum; Lo, Wendy Yat Lan; Lee, Larry Lap Yip; Chan, Jimmy Tak Shing; Tang, Simon Yiu Hang; Kalinowski, Edward

2012-08-01

216

Multiple-step triangular-pattern phase shifting and the influence of number of steps and pitch on measurement accuracy  

SciTech Connect

We present new extensions of the two-step, triangular-pattern phase-shifting method for different numbers of phase-shifting steps to increase measurement accuracy and to analyze the influence of the number of phase-shifting steps and pitch of the projected triangular intensity-profile pattern on the measurement accuracy. Phase-shifting algorithms to generate the intensity ratio, essential for surface reconstruction, were developed for each measurement method. Experiments determined that higher measurement accuracy can be obtained with a greater number of phase-shifting steps and a lower value of pitch, as long as the pitch is appropriately selected to be divisible by the number of phase-shifting steps and not below an optimal value, where intensity-ratio unwrapping failure would occur.

Jia Peirong; Kofman, Jonathan; English, Chad

2007-06-01

217

Absolute OH Number Density Measurements in Lean Fuel-Air Mixtures Excited by a Repetitively Pulsed Nanosecond Discharge.  

National Technical Information Service (NTIS)

OH Laser Induced Fluorescence (LIF) is used for temperature and absolute OH number density measurements in an atmospheric pressure, near stoichiometric CH4-air flame generated by a Hencken burner. OH rotational temperature is inferred with excitation scan...

C. D. Carter I. V. Adamovich W. R. Lempert Z. Yin

2013-01-01

218

Investigation of carrier transport through silicon wafers by photocurrent measurements  

NASA Astrophysics Data System (ADS)

A model for the minority-carrier diffusion processes which are basic to the operation of light addressable potentiometric sensor (LAPS) devices is demonstrated. Photocurrent measurements as a function of frequency provide an alternative method of measuring bulk minority-carrier lifetime, whose main advantage is to less sensitive to surface recombination. The dependence of the ac photocurrent/frequency curves for the same wafer at different wafer thicknesses was evaluated to verify the consistency of the theoretical model used. The obtained values from the semiconductor bulk and recombination velocity with the photocurrent measurement were compared with those obtained with a noncontact photoconductive decay (PCD) technique. The fundamental dependency of the ac photocurrent amplitude in LAPS devices was characterized on various parameters, namely modulation frequency, semiconductor substrate thickness, and the choice of the side of the device which is illuminated.

Bousse, Luc; Mostarshed, Shahriar; Hafeman, Dean; Sartore, Marco; Adami, Manuela; Nicolini, Claudio

1994-04-01

219

Voltammetric measurements of the transient and steady mass transport effects of ultrasound  

NASA Astrophysics Data System (ADS)

Ultrasound is useful in a variety of industrial and medical processes. Many studies have emphasized the phenomena of cavitation as the primary mechanism for the effects of ultrasound. Ultrasound gives rise to other effects such as acoustic streaming and field induced fluid motion, and these effects also create useful actions. This dissertation focuses upon understanding the basic nature of ultrasound as an interfacial mass transport mechanism. Electrochemistry provides an excellent set of methodologies for studying the interfacial effects of ultrasound. Electrochemical measurements are highly sensitive to mass transport effects at the solid electrode-liquid electrolyte interface. This study employs established techniques that probe mass transport in electrochemical systems, including dual electrode systems such as the ring-disk electrode and the interdigitated array electrode. A chemiluminescent probe molecule, luminol, 3- aminophthalhydrazide, is used to provide visual imaging of the ultrasonic field. This process has been previously used to examine the relative effects of ultrasonic cavitation in a reaction vessel, but the use of this probe molecule in a sonoelectrochemical reaction system is novel. The high transport rates possible with ultrasound enable precise electroanalytical measurements with limits of detection on the order of 10-7 mol/L. It is observed that the characteristically oscillating portion of the current signal in sonoelectrochemical measurements depends on the analyte concentration. This dependence arises from a modulated mass transport effect, and this study makes a heretofore unreported application of this modulation to an electroanalytical measurement. The effects of electrolyte viscosity, ultrasound intensity, and signal filtering on this modulated signal are reported. Cavitation is only one of the factors affecting interfacial mass transport by ultrasound. Collection efficiency and electrochemiluminescence studies show that acoustic streaming is the primary steady force in ultrasonic mass transport. The observed modulation of mass transport by ultrasound demonstrates that the field induced fluid motion generated by ultrasound also affects mass transport to a significant degree.

Cooper, Evan Lloyd

220

Transport measurements on a thin Nb film with square array of nanoscale magnetic dots.  

NASA Astrophysics Data System (ADS)

Transport measurements (R vs. T, R vs. B, and V-I characteristics) were made on a thin Nb film deposited on top of a square array of nanoscale magnetic dots [1]. These measurements established that in many ways this system behaved like a Josephson junction array (JJA). We hypothesized that the stray magnetic field of the dots reduced the superconductivity in the Nb film in such a way as to make the film a superconductor-weaker superconductor-superconductor (S-S-S) JJA. Studies of the VIs in the presence of a radio frequency (rf) signal revealed the appearance of Shapiro steps in the VI's. The voltage location at which the steps occurred follow the Josephson relation Vn=n*N*(h/2)*?, where n=1,2,3, etc, N is the number of junctions along the current direction, and ? is the frequency of the rf signal. Sample provided by Dr. Axel Hoffmann from Argonne National Laboratory and Dr. Ivan K. Schuller from UCSD. [1] J. I. Martin, Y. Jaccard, A. Hoffmann, J. Nogues, J. M. George, J. I. Vicent, and I. K. Schuller, J. Appl. Physics. 84, 411 (1998)

Gómez, Luis B.; Mast, David B.

2002-03-01

221

Time-dependent measurements over membrane plates at low Reynolds number  

Microsoft Academic Search

A segment of low Reynolds number aerodynamic research employs biomimetics for optimization of airfoil shapes to micro air vehicle (MAV) flight. Many of these efforts focus on thin, flexible membrane airfoils inspired by small birds, bats and insects. This design approach, mimicking low Reynolds number flyers (Re < 100,000), has led to improved aerodynamic performance, particularly the mitigation of flow

James Hubner; Kyle Scott; Amory Timpe; Lawrence Ukeiley

2010-01-01

222

STM and transport measurements of highly charged ion modified materials  

Microsoft Academic Search

Careful measurements of highly charged ions (HCIs) colliding with gases and surfaces have provided glimpses of intense electronic interactions, but a comprehensive model for the interaction mechanisms, time scales, and resultant nano-features that bridges materials systems is yet to be realized. At the National Institute of Standards and Technology (NIST) electron beam ion trap (EBIT) facility, new apparatus is now

J. M. Pomeroy; H. Grube; A. C. Perrella; J. D. Gillaspy

2007-01-01

223

Nanopore Unitary Permeability Measured by Electrochemical and Optical Single Transporter Recording  

PubMed Central

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 transparent foils containing either microholes or microcavities. Prototypic protein nanopores were formed in bilayer membranes by addition of Staphylococcus aureus ?-hemolysin (?-HL). Microhole arrays were used to monitor the formation of bilayer membranes and single ?-HL pores by confocal microscopy and electrical recording. Microcavity arrays were used to characterize the formation of bilayer membranes and the flux of fluorescent substrates and inorganic ions through single transporters by confocal microscopy. Thus, the unitary permeability of the ?-HL pore was determined for calcein and Ca2+ ions. The study paves the way for an amalgamation of electrical and optical single transporter recording. Electro-optical single transporter recording could provide so far unresolved kinetic data of a large number of cellular transporters, leading to an extension of the nanopore sensor approach to the single molecule analysis of peptide transport by translocases.

Hemmler, Roland; Bose, Guido; Wagner, Richard; Peters, Reiner

2005-01-01

224

Single molecule detection in nanofluidic digital array enables accurate measurement of DNA copy number  

Microsoft Academic Search

Digital polymerase chain reaction (PCR) is a promising technique for estimating target DNA copy number. PCR solution is distributed\\u000a throughout numerous partitions, and following amplification, target DNA copy number is estimated based on the proportion of\\u000a partitions containing amplified DNA. Here, we identify approaches for obtaining reliable digital PCR data. Single molecule\\u000a amplification efficiency was significantly improved following fragmentation of

Somanath Bhat; Jan Herrmann; Paul Armishaw; Philippe Corbisier; Kerry R. Emslie

2009-01-01

225

Multifunctional heat pulse probe measurements of coupled vadose zone flow and transport  

Microsoft Academic Search

Simultaneous measurement of coupled water, heat, and solute transport in unsaturated porous media is made possible with the multi-functional heat pulse probe (MFHPP). The probe combines a heat pulse technique for estimating soil heat properties, water flux, and water content with a Wenner array measurement of bulk soil electrical conductivity (ECbulk). To evaluate the MFHPP, we conducted controlled steady-state flow

Annette P. Mortensen; Jan W. Hopmans; Yasushi Mori; Jirka Simunek; A. Tuli

2005-01-01

226

Sea level variation as an indicator of Florida current volume transport: comparisons with direct measurements  

Microsoft Academic Search

Sea level measurements from tide gauges at Miami, Florida, and Cat Cay, Bahamas, and bottom pressure measurements from a water depth of 50 meters off Jupiter, Florida, and a water depth of 10 meters off Memory Rock, Bahamas, were correlated with 81 concurrent direct volume transport observations in the Straits of Florida. Daily-averaged sea level from either gauge on the

G. A. Maul; F. Chew; M. Bushnell; D. A. Mayer

1985-01-01

227

Sea Level Variation as an Indicator of Florida Current Volume Transport: Comparisons with Direct Measurements  

Microsoft Academic Search

Sea level measurements from tide gauges at Miami, Florida, and Cat Cay, Bahamas, and bottom pressure measurements from a water depth of 50 meters off Jupiter, Florida, and a water depth of 10 meters off Memory Rock, Bahamas, were correlated with 81 concurrent direct volume transport observations in the Straits of Florida. Daily-averaged sea level from either gauge on the

George A. Maul; Frank Chew; Mark Bushnell; Dennis A. Mayer

1985-01-01

228

Stochastic analysis of concentration measurements in the transport experiment at Twin Lake site  

Microsoft Academic Search

A procedure to identify the parameters characterizing flow and transport in heterogeneous aquifers with the aid of concentration measurements in tracer field experiments is developed. Unlike previous studies, which employed the measured plume spatial moments at different times and their theoretical expressions, we rely here on breakthrough curves and temporal moments in order to analyze the field tests at Chalk

G. Dagan; P. Indelman; G. Moltyaner

1997-01-01

229

Stochastic analysis of concentration measurements in the transport experiment at Twin Lake Site  

Microsoft Academic Search

A procedure to identify the parameters characterizing flow and transport in heterogeneous aquifers with the aid of concentration measurements in tracer field experiments is developed. Unlike previous studies, which employed the measured plume spatial moments at different times and their theoretical expressions, we rely here on breakthrough curves and temporal moments in order to analyze the field tests at Chalk

G. Dagan; P. Indelman; G. Moltyaner

1997-01-01

230

Effect of sidewall conductance on heat-transport measurements for turbulent Rayleigh-Bénard convection  

Microsoft Academic Search

For measurements of turbulent heat transport in Rayleigh-Bénard convection the correction for the sidewall conductance is usually neglected or based on measurements or estimates for the empty cell. It is argued that the lateral thermal coupling between the fluid and the wall can invalidate these approaches, and that corrections based on calculations of the two-dimensional temperature fields are required in

Guenter Ahlers

2001-01-01

231

Electrophoretic NMR measurements of lithium transference numbers in polymer gel electrolytes  

SciTech Connect

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.

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

232

Kinetic Evaluation of [11C]Dihydrotetrabenazine by Dynamic PET: Measurement of Vesicular Monoamine Transporter  

Microsoft Academic Search

(+)-?-[11C]Dihydrotetrabenazine (DTBZ) binds to the vesicular monoamine transporter (VMAT2) located in presynaptic vesicles. The purpose of this work was to evaluate various model configurations for analysis of [11C]DTBZ with the aim of providing the optimal measure of monoamine vesicular transporter density obtainable from a single dynamic PET study. PET studies on seven young normal volunteer subjects, ages 20–35, were performed

R. A. Koeppe; K. A. Frey; T. M. Vander Borght; A. Karlamangla; D. M. Jewett; L. C. Lee; M. R. Kilbourn; D. E. Kuhl

1996-01-01

233

Extending monetary values to broader performance and impact measures: Transportation applications and lessons for other fields.  

PubMed

This article examines recent progress at assigning monetary values to what are normally considered "hard to quantify" benefits of transportation projects. It focuses on three types of impacts - environmental quality, health and wider economic impacts - to examine how transportation project evaluation methods have evolved in recent years and how they compare to methods used for evaluation of non-transportation programs. Examples of recent practice are provided to show how transport agencies are continuing to refine performance measures to include broader impacts in project evaluation. A classification is provided to distinguish direct traveler effects from indirect effects on non-travelers, a step important to maximize coverage and minimize double-counting of impacts. For each type of impact, the paper discusses the range of variation in monetized values and shows that the variation is due less to imprecision in measurement than to fundamental issues about whether to use damage compensation, impact avoidance costs, stated preferences or behavioral valuation perspectives to define those values. Case studies as diverse as Australian roads, Wisconsin energy programs and Appalachian economic development programs are used to show how common methods are evolving among transport and non-transport agencies to improve impact measurement and its use in project evaluation. PMID:19625086

Weisbrod, Glen; Lynch, Teresa; Meyer, Michael

2009-06-26

234

MEASUREMENTS AND COMPUTATIONS OF FUEL DROPLET TRANSPORT IN TURBULENT FLOWS  

SciTech Connect

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

Joseph Katz and Omar Knio

2007-01-10

235

Experimental measurement of efficiency and transport coherence of a cold-atom Brownian motor in optical lattices.  

PubMed

The rectification of noise into directed movement or useful energy is utilized by many different systems. The peculiar nature of the energy source and conceptual differences between such Brownian motor systems makes a characterization of the performance far from straightforward. In this work, where the Brownian motor consists of atoms interacting with dissipative optical lattices, we adopt existing theory and present experimental measurements for both the efficiency and the transport coherence. We achieve up to 0.3% for the efficiency and 0.01 for the Péclet number. PMID:21405800

Zelan, M; Hagman, H; Labaigt, G; Jonsell, S; Dion, C M

2011-02-03

236

WATER SPRAY AND EXTENDED DRY TIME TO LOWER BACTERIAL NUMBERS ON SOILED FLOORING FROM BROILER TRANSPORT CAGES  

Technology Transfer Automated Retrieval System (TEKTRAN)

Broiler transport cages soiled with Campylobacter positive feces have been demonstrated to result in cross contamination of processed broiler carcasses. Washing and sanitizing cage surfaces does not always effectively eliminate bacteria. The objective of this study was to examine drying as a means...

237

Water Spray and Immersion in Chemical Sanitizer to Lower Bacterial Numbers on Broiler Transport Coop Flooring1  

Microsoft Academic Search

SUMMARY Broiler transport coops become soiled with feces during use. When this fecal matter contains Campylobacter, the result can be cross-contamination of subsequent flocks that were previously free of this important human pathogen. Because washing and sanitizing coops requires large amounts of water and is not always effective enough to justify the expense, few broiler companies wash and sanitize dump

M. E. Berrang; J. K. Northcutt

238

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

PubMed

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

Kaufman, J W; Farahmand, K

2005-06-24

239

Lipid droplets purified from Drosophila embryos as an endogenous handle for precise motor transport measurements.  

PubMed

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

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

2013-09-01

240

From Computing with Numbers to Computing with Words - From Manipulation of Measurements to Manipulation of Perceptions  

Microsoft Academic Search

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

Lotfi A. Zadeh

2000-01-01

241

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

ERIC Educational Resources Information Center

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

Ericson, T. J.

1988-01-01

242

Density-of-states effective mass and scattering parameter measurements by transport phenomena in thin films  

NASA Astrophysics Data System (ADS)

A novel machine has been developed to measure transport coefficients in the temperature range of 50-350 K of thin films deposited on electrically insulating substrates. The measured coefficients-resistivity, Hall, Seebeck, and Nernst-are applied to solutions of the Boltzmann transport equation to give information about the film's density-of-states effective mass, the Fermi energy level, and an energy-dependent scattering parameter. The machine is designed to eliminate or compensate for simultaneously occurring transport phenomena that would interfere with the desired measured quantity, while allowing for all four coefficients to be measured on the same sample. An average density-of-states effective mass value of 0.29+/-0.04me was measured on the transparent conductive oxide, cadmium stannate (CTO), over a carrier concentration range of 2-7×1020 cm-3. This effective mass value matched previous results obtained by optical and thermoelectric modeling. The measured scattering parameter indicates that neutral impurities or a mixture of scattering mechanisms may inhibit the transport of carriers in CTO.

Young, D. L.; Coutts, T. J.; Kaydanov, V. I.

2000-02-01

243

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

NASA Astrophysics Data System (ADS)

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

Molero, Francisco; Pujadas, Manuel

2008-10-01

244

Measurement of the transport spin polarization of FeV using point-contact Andreev reflection  

SciTech Connect

The Fe1 xVx alloy system exhibits the lowest known Gilbert relaxation rate of any ferromagnetic metal or binary alloy with G1 435MHz at x1 427% V. Low relaxation rates are of particular interest in modern spin electronic applications involving spin torque. The transport spin polarization of a series of sputtered epitaxial Fe1 xVx samples was measured using point contact Andreev reflection. Values of the transport spin polarization agree well with those measured for pure Fe and are independent of composition. The results indicate that the substitution of up to 50% of V for Fe does not reduce the spin polarization in the alloy.

Bailey, William [Columbia University; Osofsky, Mike [Naval Research Laboratory, Washington, D.C.; Bussman, Konrad [Naval Research Laboratory, Washington, D.C.; Parker, David S [ORNL; Cheng, L [Columbia University

2013-01-01

245

Transport Measurements of Multi-terminal MoS2 Devices  

NASA Astrophysics Data System (ADS)

We report progress on the fabrication and measurement of multi-terminal devices based on few-layer MoS2. By using different contact metal recipes, we describe efforts to significantly decrease contact resistance and gain access to the intrinsic transport properties of MoS2. We measured four-terminal resistance of monolayer, bilayer, and trilayer MoS2 with Ohmic contacts to obtain the intrinsic field-effect mobility of these materials on SiO2 substrates at temperatures down to 4 K. We also probed Hall transport of MoS2 and extracted the temperature dependence of its Hall mobility.

Yang, Y.; Churchill, H. O. H.; Baugher, B. W. H.; Jarillo-Herrero, P.

2013-03-01

246

Use of Acoustic Doppler Instruments for Measuring Discharge in Streams with Appreciable Sediment Transport  

USGS Publications Warehouse

The use of Acoustic Doppler current profilers (ADCP) for measuring discharge in streams with sediment transport was discussed. The studies show that the acoustic frequency of an ADCP in combination with the sediment transport characteristics in a river causes the ADCP bottom-tracking algorithms to detect a moving bottom. A moving bottom causes bottom-tracking-referenced water velocities and discharges to be biased low. The results also show that the use of differential global positioning system (DGPS) data allows accurate measurement of water velocities and discharges in such cases.

Mueller, D. S.

2002-01-01

247

Optical measurement of the gas number density in a Fabry-Perot cavity  

NASA Astrophysics Data System (ADS)

An optical method for measuring the gas density by monitoring the refractive index inside a high-finesse Fabry-Perot cavity is presented. The frequency of a narrow linewidth Er:fiber laser, locked to a mode of the cavity, is measured with the help of an optical frequency comb while the gas density inside the cavity changes. A resolution of 1.4 × 10-6 mol m-3 is achieved in 3 s for nitrogen, which allows measurement of a relative gas density change of 3.4 × 10-8 at atmospheric pressure.

Silander, Isak; Zelan, Martin; Axner, Ove; Arrhén, Fredrik; Pendrill, Leslie; Foltynowicz, Aleksandra

2013-10-01

248

Measurement of atomic number and mass attenuation coefficient in magnesium ferrite  

Microsoft Academic Search

Pure magnesium ferrite sample was prepared by standard ceramic technique and characterized by X-ray diffraction method. XRD pattern revealed that the sample possess single-phase cubic spinel structure. The linear attenuation coefficient (mu), mass attenuation coefficient (mu\\/rho), total atomic cross-section (sigma_{tot}), total electronic cross-section (sigma_{ele}) and the effective atomic number (Z_{eff}) were calculated for pure magnesium ferrite (MgFe_{2}O_{4}). The values of

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

2007-01-01

249

Suspended solids transport: an analysis based on turbidity measurements and event based fully calibrated hydrodynamic models.  

PubMed

Modelling suspended solids transport is a key issue for predicting the pollution load discharged by CSOs. Nonetheless, there is still much debate on the main drivers for suspended solids transport and on the modelling approach to be adopted. Current sewer models provide suspended solids transport models. These models, however, rely upon erosion-deposition criteria developed in fluvial environments, therewith oversimplifying the sewer sediment characteristics. Consequently, the performance of these models is poor from a theoretical point of view. To get an improved understanding of the temporal and spatial variations in suspended solids transport, a measuring network was installed in the sewer system of Loenen in conjunction with a hydraulic measuring network from June through December 2001. During the measuring period, 15 storm events rendered high-quality data on both the hydraulics and the turbidity. For each storm event, a hydrodynamic model was calibrated using the Clemens' method. The conclusion of the paper is that modelling of suspended solids transport has been and will be one of the challenges in the field of urban drainage modelling. A direct relation of either shear stress or flow velocity with turbidity could not be found, likely because of the time varying characteristics of the suspended solids. PMID:16206848

Langeveld, J G; Veldkamp, R G; Clemens, F

2005-01-01

250

Simultaneous measurement of glucose transport and utilization in the human brain  

PubMed Central

Glucose is the primary fuel for brain function, and determining the kinetics of cerebral glucose transport and utilization is critical for quantifying cerebral energy metabolism. The kinetic parameters of cerebral glucose transport, KMt and Vmaxt, in humans have so far been obtained by measuring steady-state brain glucose levels by proton (1H) NMR as a function of plasma glucose levels and fitting steady-state models to these data. Extraction of the kinetic parameters for cerebral glucose transport necessitated assuming a constant cerebral metabolic rate of glucose (CMRglc) obtained from other tracer studies, such as 13C NMR. Here we present new methodology to simultaneously obtain kinetic parameters for glucose transport and utilization in the human brain by fitting both dynamic and steady-state 1H NMR data with a reversible, non-steady-state Michaelis-Menten model. Dynamic data were obtained by measuring brain and plasma glucose time courses during glucose infusions to raise and maintain plasma concentration at ?17 mmol/l for ?2 h in five healthy volunteers. Steady-state brain vs. plasma glucose concentrations were taken from literature and the steady-state portions of data from the five volunteers. In addition to providing simultaneous measurements of glucose transport and utilization and obviating assumptions for constant CMRglc, this methodology does not necessitate infusions of expensive or radioactive tracers. Using this new methodology, we found that the maximum transport capacity for glucose through the blood-brain barrier was nearly twofold higher than maximum cerebral glucose utilization. The glucose transport and utilization parameters were consistent with previously published values for human brain.

Shestov, Alexander A.; Emir, Uzay E.; Kumar, Anjali; Henry, Pierre-Gilles; Seaquist, Elizabeth R.

2011-01-01

251

Detection of excited level population transfer in an MOT through the measurement of trapped atom number  

NASA Astrophysics Data System (ADS)

We study the rubidium magneto-optical trap (MOT) population changes induced by a laser beam interacting with the trapped atoms and resonant with different transitions from both the ground and the excited trap levels. Laser excitation outside the cooling scheme induces losses in the MOT population, while the laser increases the trap population when tuned to transitions linked to the trapping cycle. The experiment is performed with a small number of trapped atoms (100 to 10 000). A discussion of our ability in manipulating the atomic population of different hyperfine states is reported.

Moi, L.; Batignani, G.; Khanbekyan, A.; Khanbekyan, K.; Marinelli, C.; Mariotti, E.; Marmugi, L.; Corradi, L.; Dainelli, A.; Calabrese, R.; Mazzocca, G.; Tomassetti, L.; Minguzzi, P.

2013-01-01

252

Measurement of atomic number and mass attenuation coefficient in magnesium ferrite  

Microsoft Academic Search

Pure magnesium ferrite sample was prepared by standard ceramic technique and characterized by X-ray diffraction method. XRD\\u000a pattern revealed that the sample possess single-phase cubic spinel structure. The linear attenuation coefficient (µ), mass attenuation coefficient (µ\\/?), total atomic cross-section (?\\u000a tot), total electronic cross-section (?\\u000a ele) and the effective atomic number (Z\\u000a eff) were calculated for pure magnesium ferrite (MgFe2O4).

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

2007-01-01

253

Laboratory measurements of the transport of radon gas through concrete samples  

SciTech Connect

Experiments were conducted to measure the transportability of radon gas through common concrete samples which were characterized by their mix proportions, dimensions, porosity, air permeability, and radon gas diffusion coefficient. Several innovative test systems and methods were designed, fabricated, and calibrated to accurately measure these radon gas transport characteristics for concrete and to overcome many of the shortcomings of previously published experimental works. From the experimental results, it was found that diffusion is the dominant transport mechanism by which radon gas moves through an intact concrete slab. It was also shown that indoor radon entry rates can be greatly affected by the type of concrete mix employed. The results of this study can be utilized to improve the present technology of radon-resistant construction techniques for new residential construction. 22 refs., 6 figs., 4 tabs.

Renken, K.J.; Rosenberg, T. [Univ. of Wisconsin, Milwaukee, WI (United States)

1995-06-01

254

Analysis of modulated free-carrier absorption measurement of electronic transport properties of silicon wafers  

NASA Astrophysics Data System (ADS)

Based on a three-dimensional modulated free carrier absorption (MFCA) model, theoretical analysis is performed to investigate the dependences of MFCA amplitude and phase on the electronic transport properties (the carrier lifetime, the carrier diffusivity, and the front surface recombination velocity) at different pump-to-probe separations and different modulation frequencies. The sensitivity of the multi-parameter estimate employing the dependences of the MFCA amplitude and phase on the modulation frequency at several pump-to-probe separations is theoretically compared with that employing the dependences on the pump-to-probe separation measured at several modulation frequencies. Simulation results show that the two approaches have comparable sensitivities to the electronic transport properties of silicon wafers. As for the MFCA experiments, the frequency scan data measured at different pump-to-probe separations have higher signal-to-noise ratios and therefore should be preferable to the simultaneous determination of the multiple transport properties.

Li, Wei; Li, Bincheng

2010-03-01

255

Laboratory measurements of the transport of radon gas through concrete samples.  

PubMed

Experiments were conducted to measure the transportability of radon gas through common concrete samples which were characterized by their mix proportions, dimensions, porosity, air permeability, and radon gas diffusion coefficient. Several innovative test systems and methods were designed, fabricated, and calibrated to accurately measure these radon gas transport characteristics for concrete and to overcome many of the shortcomings of previously published experimental works. From the experimental results, it was found that diffusion is the dominant transport mechanism by which radon gas moves through an intact concrete slab. It was also shown that indoor radon entry rates can be greatly affected by the type of concrete mix employed. The results of this study can be utilized to improve the present technology of radon-resistant construction techniques for new residential construction. PMID:7759258

Renken, K J; Rosenberg, T

1995-06-01

256

Selection of the Number and Positions of Measuring Locations for Electrocardiography  

Microsoft Academic Search

This paper considers how many and which locations on the body surface must be measured (by taking ECGs at these positions) to be able to determine consistently the total-body QRS surface-potential distribution as it varies in time. The answers to these questions have implications about the complexity of models of heart electrical activity in addition to their experimental value. An

Roger C. Barr; Madison S. Spach; G. Scott Herman-Giddens

1971-01-01

257

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

Microsoft Academic Search

A new plastic microlens array, consisting of 900 lenslets, has been developed for the Shack Hartmann wave-front sensor. The individual lens is 300 µm 3 300 µm and has a focal length of 10 mm, which provides the same focal size, 60 µm in diameter, with a constant peak intensity. One can improve the wave-front measurement accuracy by reducing the

Geun Young Yoon; Takahisa Jitsuno; Masahiro Nakatsuka; Sadao Nakai

1996-01-01

258

THE MEASUREMENT OF VOCATIONAL NEEDS. MINNESOTA STUDIES IN VOCATIONAL REHABILITATION, NUMBER 16.  

ERIC Educational Resources Information Center

|TWO QUESTIONNAIRES FOR MEASURING VOCATIONAL NEEDS WERE DEVELOPED. NEED WAS DEFINED AS "NEED FOR SPECIFIED REINFORCING CONDITIONS IN THE WORK ENVIRONMENT." THE N-FACTORS QUESTIONNAIRE (NFQ) CONSISTED OF 48 TWO-RESPONSE CHOICE ITEMS, FOUR ITEMS FOR EACH OF 12 SCALES--ACHIEVEMENT, AUTHORITY, COWORKERS, CREATIVITY AND CHALLENGE, DEPENDENCE,…

WEISS, DAVID J.; AND OTHERS

259

Endwall heat transfer measurements in an annular cascade of nozzle guide vanes at engine representative Reynolds and Mach numbers  

Microsoft Academic Search

Aerodynamic and heat transfer measurements have been made on the hub and casing endwalls of a large (mean diameter 1.1 m) annular cascade of high-pressure nozzle guide vanes. The measurements have been made over a range of engine representative Mach and Reynolds numbers and with large levels of free-stream turbulence intensity. The transient liquid crystal technique has been employed, which

G. D. Lock

1996-01-01

260

Challenges in Measuring and Predicting Medium Term (Weeks to Annual) Aeolian Sediment Transport in Beach-Dune Systems  

NASA Astrophysics Data System (ADS)

Coastal dune budgets depend on sediment input by wind from the beach. Calculation of aeolian transport is thus a primary factor to understand coastal dune evolution and beach-dune coupled dynamics. However, measuring aeolian sediment transport in coastal areas presents fundamental technical and conceptual limitations that make numerical modeling difficult. Wind tunnel experiments isolate and reduce the number of variables to study, which is a necessary procedure to clearly manifest mechanistic relationships between cause and effect. But even with refinement and inclusion of new variables, traditional sediment transport formulas derived from wind tunnel experiments do not usually work well in natural areas. Short-term experiments may include precise instrumentation to obtain high frequency, detail time series of variables involved in aeolian transport, but inferring information at larger scales is problematic without knowledge of the timing and magnitude of particular transport events. There are two primary problems in attempting to predict sediment inputs to coastal dunes over periods of weeks, months or years: 1) to determine an appropriate set of predictive equations that incorporate complexities such as surface moisture content, beach width and the presence of vegetation; and 2) to provide quantitative data on these variables for input into the model at this time scale. Remote sensing techniques and the use of GIS software open the possibility to monitor key parameters regulating sediment transport dynamics at high spatial and temporal resolution over time scales beyond short-term experiments. These were applied at Greenwich Dunes, Prince Edward Island National Park (Canada), in an attempt to measure factors affecting aeolian sediment input to the foredune at a medium scale. Three digital cameras covering different sections of the beach and foredune provide time series on shoreline position, fetch distances, vegetation cover, ice/snow presence, or superficial moisture content. The rectification of oblique images to UTM maps allows to keep the spatial variability of these factors, and thus to perform detailed analysis on their complex evolution. Auxiliary instrumentation such as anemometers, safires, or erosion-deposition pins completes the basic set up. Data is processed using ArcGIS 9.2 and PCI Geomatica 9.1, and managed by an ArcCatalog Geodatabase. The coupling of new technologies (digital imagery) with traditional instrumentation (e.g. anemometers), and the extensive GIS capabilities both in the spatial and temporal domain, permits a new set of questions in aeolian coastal research. The overall goal is to obtain information on what is the frequency and magnitude of transport events at the beach or what are the key parameters regulating them. Challenges remain in improving methodologies to measure sediment transport rates. Ironically enough, we are able to obtain high quality time series on the factors affecting aeolian transport at the beach, but actual transport rates are measured with rather rudimentary techniques or instrumentation not adapted to meso-scale monitoring. This information is needed to test new approaches in modeling and understanding aeolian sediment input from the beach to the foredunes.

Delgado-Fernandez, I.

2009-05-01

261

Improvement of storage, handling, and transportability of fine coal. Quarterly technical progress report number 8, October 1--December 31, 1995  

SciTech Connect

The Mulled Coal process was developed as a means of overcoming the adverse handling characteristics of wet fine coal without thermal drying. The process involves the addition of a low cost, harmless reagent to wet fine coal using off-the-shelf mixing equipment. Based on laboratory- and bench-scale testing, Mulled coal can be stored, shipped, and burned without causing any of the plugging, pasting, carryback and freezing problems normally associated with wet coal. On the other hand, Mulled Coal does not cause the fugitive and airborne dust problems normally associated with thermally dried coal. The objectives of this project are to demonstrate that: the Mulled Coal process, which has been proved to work on a wide range of wet fine coals at bench scale, will work equally well on a continuous basis, producing consistent quality, and at a convincing rate of production in a commercial coal preparation plant; the wet product from a fine coal cleaning circuit can be converted to a solid fuel form for ease of handling and cost savings in storage and rail car transportation; and a wet fine coal product thus converted to a solid fuel form, can be stored, shipped, and burned with conventional fuel handling, transportation, and combustion systems.

NONE

1996-03-15

262

Measured performances on vectorization and multitasking with a Monte Carlo code for neutron transport problems  

Microsoft Academic Search

This paper summarized two improvements of a real production code by using vectorization and multitasking techniques. After a short description of Monte Carlo algorithms employed in our neutron transport problems, we briefly describe the work we have done in order to get a vector code. Vectorization principles will be presented and measured performances on the CRAY 1S, CYBER 205 and

Yves Chauvet

1985-01-01

263

Measurement of pernitric acid, hydrogen chloride, and sulfur dioxide during the Intercontinental Chemical Transportation Experiment campaign  

Microsoft Academic Search

This study presents airborne measurements (0 km < z < 12 km) of HO2NO2, HCl and SO2 using chemical ionization mass spectrometry (CIMS) during the Intercontinental Chemical Transport Experiment (INTEX) field campaign, an intensive study to characterize the chemical composition of the troposphere in the eastern United States, Mexico City, and the North Pacific which is the outflow region of

Sae Wung Kim

2007-01-01

264

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...

265

Time-Resolved Measurements of the Ionization Front in Transport Studies.  

National Technical Information Service (NTIS)

Characterization of the ionization front associated with thermal transport in laser-irradiated CH targets, as measured by x-ray emission from imbedded thin metallic layers, will be discussed. Observations of time-resolved filter spectrometry and time-inte...

R. S. Marjoribanks M. C. Richardson B. Yaakobi O. Barnouin J. Delettrez

1984-01-01

266

DIRECT MEASUREMENT OF FAST AXONAL ORGANELLE TRANSPORT IN THE SCIATIC NERVE OF RATS TREATED WITH ACRYLAMIDE  

EPA Science Inventory

The effects of acrylamide on fast axonal transport have been measured primarily using the indirect methods of isotope or enzyme accumulation. e report the first direct evaluation of the effects of sub-chronic acrylamide dosing (150, 300 or 500 mg/kg total dose) on the fast axonal...

267

Measurements of Combined Axial Mass and Heat Transport in He II.  

ERIC Educational Resources Information Center

|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…

Johnson, Warren W.; Jones, Michael C.

268

Transport and tunnelling measurements in superconducting YNi2B2C  

NASA Astrophysics Data System (ADS)

New transport (resistivity versus temperature) and tunneling (low-temperature STM) measurements are reported on YNi2B2C samples prepared by inductive melting from the pure elements. Estimations of Debye temperature, electron-phonon interaction parameter ?, plasma frequency and superconducting energy gap are given. Normal-state and superconducting data fit in a consistent picture of BCS superconductivity with ?<=1.

Vaglio, R.; Fontana, F.; Andreone, A.; Iavarone, M.; Canepa, F.; Manfrinetti, P.; Palenzona, A.

1995-02-01

269

AC loss measurements of a high critical temperature superconductor transporting sinusoidal or non-sinusoidal current  

Microsoft Academic Search

In electrical engineering, static converters generate harmonics; consequently the losses in the conductors increase. To use High-Tc superconductors for current transportation, it is important to evaluate and to measure their losses. Under the assumption that the superconductor is only exposed to its self-field, Bean's model is used to compute these losses. This work deals with the losses in a cylindrical

B. Douine; J. Leveque; A. Rezzoug

2000-01-01

270

A backward modeling study of intercontinental pollution transport using aircraft measurements  

Microsoft Academic Search

In this paper we present simulations with a Lagrangian particle dispersion model to study the intercontinental transport of pollution from North America during an aircraft measurement campaign over Europe. The model was used for both the flight planning and a detailed source analysis after the campaign, which is described here with examples from two episodes. Forward calculations of emission tracers

A. Stohl; C. Forster; S. Eckhardt; N. Spichtinger; H. Huntrieser; J. Heland; H. Schlager; S. Wilhelm; F. Arnold; O. Cooper

2003-01-01

271

A Backward Modeling Study of Intercontinental Pollution Transport Using Aircraft Measurements  

Microsoft Academic Search

In this paper we present simulations with a Lagrangian particle dispersion model to study the intercontinental transport of pollution from North America during an aircraft measurement campaign over Europe. The model was used for both the flight planning and a detailed source analysis after the campaign, which is described here with examples from two episodes. First, forward calculations of emission

A. Stohl; C. Forster; S. Eckhardt; H. Huntrieser; J. Heland; H. Schlager; H. Aufmhoff; F. Arnold; O. Cooper

2002-01-01

272

Towards a Modal Shift in Freight Transport? A Business Logistics Analysis of Some Policy Measures  

Microsoft Academic Search

This paper analyses the effectiveness of policy measures aimed at triggering a modal shift in the freight transport market. The analysis is based on the inventory?theoretic framework that studies modal choice from a business logistics viewpoint. The crux of the inventory?theoretic approach lies in the fact that explicit attention is paid to all costs in the supply chain that are

Gust Blauwens; Nico Vandaele; Eddy Van de Voorde; Bert Vernimmen; Frank Witlox

2006-01-01

273

Measurement of fuel mixing and transport processes in gas turbine combustion  

Microsoft Academic Search

The measurement techniques for delineating fuel-air mixing and transport in gas turbine combustion, as well as examples of representative results, are provided in this overview. The summary is broken into applications for gaseous fuels and liquid fuels since many diagnostics which are specific to the phase of the fuel have been developed. Many possible methods for assessing the general mixing

V. G. McDonell; G. S. Samuelsen

2000-01-01

274

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

Microsoft Academic Search

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

T. G. Owens; F. D. King

1975-01-01

275

Measurement of atomic number and mass attenuation coefficient in magnesium ferrite  

NASA Astrophysics Data System (ADS)

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

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

2007-05-01

276

Cryptographically secure hardware random number generator dedicated for distributed measurement and control systems  

NASA Astrophysics Data System (ADS)

The chaotic signal generator based on the theory of nonlinear dynamical systems for applications in cryptographically secure distributed measurement and control systems with asymmetric resources is presented. This system was implemented on the basis of the physical chaotic electronic vibration generator in which the resonant circuit is composed of two capacitors, two resistors, coil and transistor, called the Colpitts oscillator. The presented system was designed, programmed and thoroughly tested in the term of cryptographic security in our laboratory, what there is the most important part of this publication. True cryptographic security was tested based on the author's software and the software environment called RDieHarder. The obtained results will be here presented and analyzed in detail with particular reference to the specificity of distributed measurement and control systems with asymmetric resources.

Czernik, Pawel

2012-05-01

277

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

NASA Astrophysics Data System (ADS)

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

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

1992-09-01

278

Techniques for fisheye lens calibration using a minimal number of measurements  

Microsoft Academic Search

A method is discussed describing how different types of Omni-Directional fisheye lenses can be calibrated for use in robotic vision. The technique discussed will allow for full calibration and correction of x,y pixel coordinates while only taking two uncalibrated and one calibrated measurement. These are done by finding the observed x,y coordinates of a calibration target. Any Fisheye lense that

T. Nathan Mundhenk; Michael J. Rivett; Xiaoqun Liao; Ernest L. Hall

2000-01-01

279

NON-LINEAR ENGINE COMPONENT FAULT DIAGNOSIS FROM A LIMITED NUMBER OF MEASUREMENTS USING A COMBINATORIAL APPROACH  

Microsoft Academic Search

A method for diagnosing component faults of jet engines is presented. It uses non-linear gas path analysis techniques to determine the values of health parameters, with the help of a suitably formulated engine simulation model. The incentive of the method is to achieve the determination of the values of component health indices when a limited number of measured quantities is

N. Aretakis; A. Stamatis; Iroon Polytechniou

280

A Participatory Approach to the Identification of Measures of Number Sense in Children Prior to School Entry  

ERIC Educational Resources Information Center

|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…

Howell, Sally; Kemp, Coral

2009-01-01

281

Historical Increase in the Number of Factors Measured by Commercial Tests of Cognitive Ability: Are We Overfactoring?  

ERIC Educational Resources Information Center

|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…

Frazier, Thomas W.; Youngstrom, Eric A.

2007-01-01

282

Characterisation of diesel exhaust particle number and size distributions using mini-dilution tunnel and ejector–diluter measurement techniques  

Microsoft Academic Search

This paper presents the characteristics of diesel exhaust particle number and size distributions. These were measured for different engine load conditions from 10% to 100% of full engine load at a maximum torque of constant speed, using mini-dilution tunnel and sampling (MDTS) and ejector–diluter and sampling (EDS) systems. The exhaust particles sampled were analysed using a scanning mobility particle sizer

C. P. Wong; T. L. Chan; C. W. Leung

2003-01-01

283

Spectroscopic measurements and impurity transport studies on MST Reversed Field Pinch  

NASA Astrophysics Data System (ADS)

The results of impurity transport studies in MST improved confinement pulsed poloidal current drive (PPCD) and standard regimes are presented and discussed. The impurity diffusion coefficient and pinch velocity are obtained through comparing experimental impurity density time evolution and radial profiles with the results of a 1-D impurity transport code. Experimental measurements have been obtained in the past with Charge Exchange Recombination Spectroscopy for several impurity species (C, O, B, Al). In particular previous analysis of fully stripped carbon measurements showed that carbon density decays at the core and radial profile evolves into a stationary hollow shape in PPCD discharges [S Kumar, Plasma Phys. Control. Fusion, 53 (2011) 032001]. Transport code has been applied to carbon, oxygen and boron impurities in order to deduce transport coefficients profiles which lead to the experimental impurities behaviour. Finally these coefficients have been compared with those obtained for RFX-mod Reversed Field Pinch in Quasi-Single Helicity (QSH) and Multiple Helicity (MH) regimes. In RFX-mod the pinch velocity, always directed outwards, features a transport barrier preventing impurities from penetrating into the plasma, especially in QSH regime.

Barbui, Tullio; Carraro, Lorella; Kumar, Santhosh; den Hartog, Daniel; Nornberg, Mark

2012-10-01

284

Sea level variation as an indicator of Florida current volume transport: comparisons with direct measurements  

SciTech Connect

Sea level measurements from tide gauges at Miami, Florida, and Cat Cay, Bahamas, and bottom pressure measurements from a water depth of 50 meters off Jupiter, Florida, and a water depth of 10 meters off Memory Rock, Bahamas, were correlated with 81 concurrent direct volume transport observations in the Straits of Florida. Daily-averaged sea level from either gauge on the Bahamian side of the Straits was poorly correlated with transport. Bottom pressure off Jupiter had a linear coefficient of determination of r/sup 2/ = 0.93, and Miami sea level, when adjusted for weather effects, had r/sup 2/ = 0.74; the standard errors of estimating transports were +/-1.2 x 10/sup 6/ and +/-1.9 x 10/sup 6/ cubic meters per second, respectively. A linear multivariate regression, which combined bottom pressure, weather, and the submarine cable observations between Jupiter and the Bahamas, had r/sup 2/ = 0.94 with a standard error of estimating transport of +/-1.1 x 10/sup 6/ cubic meters per second. These results suggest that a combination of easily obtained observations is sufficient to adequately monitor the daily volume transport fluctuations of the Florida Current. 13 references, 2 figures, 2 tables.

Maul, G.A.; Chew, F.; Bushnell, M.; Mayer, D.A.

1985-01-18

285

Non-invasive tools for measuring metabolism and biophysical analyte transport: self-referencing physiological sensing.  

PubMed

Biophysical phenomena related to cellular biochemistry and transport are spatially and temporally dynamic, and are directly involved in the regulation of physiology at the sub-cellular to tissue spatial scale. Real time monitoring of transmembrane transport provides information about the physiology and viability of cells, tissues, and organisms. Combining information learned from real time transport studies with genomics and proteomics allows us to better understand the functional and mechanistic aspects of cellular and sub-cellular systems. To accomplish this, ultrasensitive sensing technologies are required to probe this functional realm of biological systems with high temporal and spatial resolution. In addition to ongoing research aimed at developing new and enhanced sensors (e.g., increased sensitivity, enhanced analyte selectivity, reduced response time, and novel microfabrication approaches), work over the last few decades has advanced sensor utility through new sensing modalities that extend and enhance the data recorded by sensors. A microsensor technique based on phase sensitive detection of real time biophysical transport is reviewed here. The self-referencing technique converts non-invasive extracellular concentration sensors into dynamic flux sensors for measuring transport from the membrane to the tissue scale. In this tutorial review, we discuss the use of self-referencing micro/nanosensors for measuring physiological activity of living cells/tissues in agricultural, environmental, and biomedical applications comprehensible to any scientist/engineer. PMID:21761069

McLamore, Eric S; Porterfield, D Marshall

2011-07-15

286

Framework for evaluating transportation control measures: Energy, air quality, and mobility tradeoffs. Research report  

SciTech Connect

Transportation planners, engineers, and air quality analysts are increasingly understanding the need for coordinated efforts in providing efficient and effective transportation systems while addressing serious energy and environmental concerns. At present, however, transportation planning and air quality analysis models are rather incompatible. Emissions models require detailed inputs which are not generally provided by transportation planning and analysis tools. Traditionally, transportation planning is comprised of four stages: trip generation, trip distribution, mode choice, and network assignment. In general, a forecast population, auto ownership, employment, and land use are inputs into the stages sequentially. This planning process does not adequately account for the manner in which individuals make travel decisions. The only travel-related decision that can be predicted using this traditional planning method is the mode of travel, while transportation control measures (TCMs), affect trip generation and trip distribution as well as route and mode choice. Variables required for emissions estimation have not routinely been components of transportation planning models. What is needed is a methodology for combining transportation planning and analysis models with emissions factor models for predicting the effectiveness of various TCMs. The application of the macro-framework is demonstrated through analyses of two sample networks. The results show that the effectiveness of a TCM depends on the characteristics of the urban environment in which it is implemented. Failure to analyze the implication of a TCM prior to its implementation may yield results inconsistent with environmental and energy policy objectives. In addition, the results show that the choice of an emissions model is very critical in air quality analysis.

Euritt, M.A.; Qin, J.; Meesomboon, J.; Walton, C.M.

1994-07-01

287

Development of a scanning tunneling potentiometry system for measurement of electronic transport at short length scales  

NASA Astrophysics Data System (ADS)

It is clear that complete understanding of macroscopic properties of materials is impossible without a thorough knowledge of behavior at the smallest length scales. While the past 25 years have witnessed major advances in a variety of techniques that probe the nanoscale properties of matter, electrical transport measurements -- the heart of condensed matter research -- have lagged behind, never progressing beyond bulk measurements. This thesis describes a scanning tunneling potentiometry (STP) system developed to simultaneously map the transport-related electrochemical potential distribution of a biased sample along with its surface topography, extending electronic transport measurements to the nanoscale. Combining a novel sample biasing technique with a continuous current-nulling feedback scheme pushes the noise performance of the measurement to its fundamental limit - the Johnson noise of the STM tunnel junction. The resulting 130 nV voltage sensitivity allows us to spatially resolve local potentials at scales down to 2 nm, while maintaining atomic scale STM imaging, all at scan sizes of up to 15 microns. A mm-range two-dimensional coarse positioning stage and the ability to operate from liquid helium to room temperature with a fast turn-around time greatly expand the versatility of the instrument. Use of carefully selected model materials, combined with excellent topographic and voltage resolution has allowed us to distinguish measurement artifacts caused by surface roughness from true potentiometric features, a major problem in previous STP measurements. The measurements demonstrate that STP can produce physically meaningful results for homogeneous transport as well as non-uniform conduction dominated by material microstructures. Measurements of several physically interesting materials systems are presented as well, revealing new behaviors at the smallest length sales. The results establish scanning tunneling potentiometry as a useful tool for physics and materials science.

Rozler, Michael

288

MEASURING FLOW PARAMETERS OF PARTICULATE AND POWDERY SOLIDS IN INDUSTRIAL TRANSPORTATION PROCESSES  

Microsoft Academic Search

This paper provides an overview of existing technologies to measure flow parameters, such as material velocity and material concentration, in industrial transportation processes of particulate and powdery solids with a focus on pneumatic conveying. Restrictions, advantages and drawbacks of state of the art measurement principles are discussed. We show that capacitance-based sensing with suitable electrode topology allows for non-invasive, low-cost

A. Fuchs; H. Zangl

2008-01-01

289

Measuring acuity of the approximate number system reliably and validly: the evaluation of an adaptive test procedure  

PubMed Central

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.

Lindskog, Marcus; Winman, Anders; Juslin, Peter; Poom, Leo

2013-01-01

290

Measurement of efffective atomic numbers of holmium doped and undoped layered semiconductors via transmission method around the absorption edge  

NASA Astrophysics Data System (ADS)

Effective atomic numbers were measured for InSe and InSe having different Holmium concentrations measured in the energy region 15.746-40.930 keV using a Si(Li) detector. InSe:Holmium(0.0025), InSe:Holmium(0.0050), InSe:Holmium(0.025) InSe:Holmium(0.05) and InSe crystals have been grown by the Bridgman-Stocbarger method. The measured values were compared with the theoretical ones obtained using WinXCom being a Windows version of XCOM on the basis of mixture rule. The objective of this work is to show that there is a relation between effective atomic numbers and doped Ho fractions to InSe.

Ïçelli, Orhan

2009-03-01

291

Phonon-Magnon Interaction in Low Dimensional Quantum Magnets Observed by Dynamic Heat Transport Measurements  

NASA Astrophysics Data System (ADS)

Thirty-five years ago, Sanders and Walton [Phys. Rev. B 15, 1489 (1977)PRBMDO0163-1829] proposed a method to measure the phonon-magnon interaction in antiferromagnets through thermal transport which so far has not been verified experimentally. We show that a dynamical variant of this approach allows direct extraction of the phonon-magnon equilibration time, yielding 400?s for the cuprate spin-ladder system Ca9La5Cu24O41. The present work provides a general method to directly address the spin-phonon interaction by means of dynamical transport experiments.

Montagnese, Matteo; Otter, Marian; Zotos, Xenophon; Fishman, Dmitry A.; Hlubek, Nikolai; Mityashkin, Oleg; Hess, Christian; Saint-Martin, Romuald; Singh, Surjeet; Revcolevschi, Alexandre; van Loosdrecht, Paul H. M.

2013-04-01

292

A transportable magnetic resonance imaging system for in situ measurements of living trees: The Tree Hugger  

NASA Astrophysics Data System (ADS)

This paper presents the design of the 'Tree Hugger', an open access, transportable, 1.1 MHz 1H nuclear magnetic resonance imaging system for the in situ analysis of living trees in the forest. A unique construction employing NdFeB blocks embedded in a reinforced carbon fibre frame is used to achieve access up to 210 mm and to allow the magnet to be transported. The magnet weighs 55 kg. The feasibility of imaging living trees in situ using the 'Tree Hugger' is demonstrated. Correlations are drawn between NMR/MRI measurements and other indicators such as relative humidity, soil moisture and net solar radiation.

Jones, M.; Aptaker, P. S.; Cox, J.; Gardiner, B. A.; McDonald, P. J.

2012-05-01

293

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

NASA Astrophysics Data System (ADS)

We report spatially resolved, quantitative, in situ, nondestructive measurements of the transport of organic molecules through a polycrystalline, anisotropic, nanoporous molecular sieve membrane, with micron-scale resolution. A method based on photoacoustic spectroscopy experiments during permeation through a nanoporous membrane, combined with a physical model of photoacoustic signal generation from a heterogeneous membrane, allows extraction of concentration profiles in situ. In particular, we demonstrate the steady-state concentration profiling of the organic molecules p-xylene and n-hexane during their transport through a nanoporous zeolite silicalite membrane. The implications for elucidating structure-property relationships in membrane materials for separations, catalytic, or nanotechnology applications are discussed.

Oh, Weontae; Nair, Sankar

2005-10-01

294

Spin transport parameters in metallic multilayers determined by ferromagnetic resonance measurements of spin-pumping  

NASA Astrophysics Data System (ADS)

We measured spin-transport in nonferromagnetic (NM) metallic multilayers from the contribution to damping due to spin pumping from a ferromagnetic Co90Fe10 thin film. The multilayer stack consisted of NM1/NM2/Co90Fe10(2 nm)/NM2/NM3 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.

Boone, C. T.; Nembach, Hans T.; Shaw, Justin M.; Silva, T. J.

2013-04-01

295

Identification of Inhibitor Concentrations to Efficiently Screen and Measure Inhibition Ki Values against Solute Carrier Transporters  

PubMed Central

The objective was to identify inhibitor concentrations to efficiently screen and measure inhibition Ki values of solute carrier (SLC) transporters. The intestinal bile acid transporter and its native substrate taurocholate were used as a model system. Inhibition experiments were conducted using 27 compounds. For each compound, the inhibition constant Ki was obtained from the comprehensive inhibition profile, and referred as the reference Ki. Ki values were also estimated from various partial profiles and were compared to the reference Ki. A screening Ki was estimated from one data point and also compared to the reference Ki. Results indicate that Ki can be accurately measured using an inhibitor concentration range of only 0-Ki via five different inhibitor concentrations. Additionally, a screening concentration of 10-fold the substrate affinity Kt for potent inhibitors (Ki < 20Kt) and 100-fold Kt for nonpotent inhibitors (Ki > 20Kt) provided an accurate Ki estimation. Results were validated through inhibition studies of two other SLC transporters. In conclusion, experimental conditions to screen and measure accurate transporter inhibition constant Ki are suggested where a low range of inhibitor concentrations can be used. This approach is advantageous in that minimal compound is needed to perform studies and accommodates compounds with low aqueous solubility.

Zheng, Xiaowan; Polli, James

2010-01-01

296

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

SciTech Connect

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.

Benioff, P. (Physics)

2011-06-01

297

Measurement of a number of indices of hand and movement angles in pianists with overuse disorders.  

PubMed

Abduction angles of the thumb and little finger, hand span, length of thumb, middle finger and little finger were measured using radiographs of the right hand with the thumb and the little finger abducted, in a comparative study of 220 pianists with overuse disorder and 62 unaffected pianists. Overuse disorders included tenosynovitis, lateral and medial epicondylitis, forearm flexor muscle pain, distal tendinitis of the wrist extensors and flexors and intrinsic muscle pain. Hand span or other hand size parameters showed significant differences, while abduction angles showed no difference. The patients' group had smaller hand size than the controls when analyzed for tenosynovitis, epicondylitis and muscle pain. From these results we hypothesize that pianists with small hands tend to hyper-abduct and hyper-extend the thumb to attain greater hand span. Their little finger is also stiffer and the hypothenar muscle and the wrist flexors need greater strength to resist the reaction force in each piano key. PMID:20427408

Sakai, N; Shimawaki, S

2010-04-28

298

Two terminal and four terminal transport measurements in single crystal bismuth nanowires  

NASA Astrophysics Data System (ADS)

Bismuth nanowire arrays with uniform wire diameter and a common crystallographic direction along the nanotube axis have been synthesized in anodic alumina templates with wire diameters in the range 7--200 nm. The effect of n-type doping of the nanowires with Te at various doping concentrations has been investigated theoretically and experimentally as a means to control the position of the Fermi level. Structural characterization of the nanowire arrays are reported as a function of doping concentration and nanowire diameter. Normalized two terminal resistivity and thermopower measurements as a function of temperature have been carried out to study the semimetal-semiconductor transition. To measure the transport properties quantitatively, the bismuth nanowires are removed from their templates and four terminal contacts are made on individual nanowires using e-beam lithography techniques. Four terminal transport measurements on individual nanowires are reported. The experimental results and results of the theoretical modeling will be compared.

Cronin, S.; Lin, Yu-Ming; Black, M. R.; Ying, J. Y.; Dresselhaus, G.; Dresselhaus, M. S.

2000-03-01

299

The relationship between turbulence measurements and transport in different heating regimes in TFTR  

SciTech Connect

The scaling of broad band density fluctuations in the confinement zone of TFTR measured by microwave scattering, beam emission spectroscopy (BES), and reflectometry show a relationship between these fluctuations and energy transport measured from power balance calculations. In L-mode plasmas scattering and BES indicates that the density fluctuation level, {delta}n{sup 2}, in the confinement zone for 0.2 < k{perpendicular}ps < 1.0 depends qualitatively on P{sub aux} and I{sub p} in a way that is consistent with variations in energy transport. Fluctuation levels measured with all systems increase strongly toward the edge in all heating regimes following increases in energy transport coefficients. Measurements using BES have shown that poloidal and radial correlation lengths in the confinement zone of L-mode and supershot plasmas fall in the range of 1 to 2 cm. with a wave structure which has k{sub max} {approx} 1 cm{sup {minus}1} (k{perpendicular}ps {approx} 0.2) in the poloidal direction and k{sub max} approaching zero in the radial direction. A simple estimate of the diffusion coefficient based on a measured radial correlation length and correlation time indicates good agreement with power balance calculations. Similar estimates using reflectometry give radial coherence lengths at 10 to 20 kHz in low density ohmic and supershot plasmas of between I and 2 cm.

Bretz, N.L.; Mazzucato, E.; Nazikian, R.; Paul, S.F.; Hammett, G.; Rewoldt, G.; Tang, W.M.; Zarnstorff, M.C. [Princeton Univ., NJ (United States). Plasma Physics Lab.; Fonck, R.J.; Durst, R.; Cosby, G. [Wisconsin Univ., Madison, WI (United States)

1992-10-01

300

Local Transport Measurements at Mesoscopic Length Scales Using Scanning Tunneling Potentiometry  

NASA Astrophysics Data System (ADS)

Under mesoscopic conditions, the transport potential on a thin film carrying a current is theoretically expected to bear spatial variation due to quantum interference. Scanning tunneling potentiometry is the ideal tool to investigate such variation, by virtue of its high spatial resolution. We report in this Letter the first detailed measurement of transport potential under mesoscopic conditions. Epitaxial graphene at a temperature of 17 K was chosen as the initial system for study because the characteristic transport length scales in this material are relatively large. Tip jumping artifacts are a major possible contribution to systematic errors; and we mitigate such problems by using custom-made slender and sharp tips manufactured by focused ion beam. In our data, we observe residual resistivity dipoles associated with topographical defects, and local peaks and dips in the potential that are not associated with topographical defects.

Wang, Weigang; Munakata, Ko; Rozler, Michael; Beasley, Malcolm R.

2013-06-01

301

Measurements of mean flow and eddy transport over a film cooling surface  

SciTech Connect

Results of an experimental study of the effects of blowing Velocity Ratio (VR = 0.5 and 1.0) and Free-Stream Turbulence Intensity (FSTI = 0.5% and 12%) on turbulent transport over a film-cooling test surface are presented. The surface has a single lateral row of streamwise-oriented holes angled 35{degree} from the surface and separated from one another by three hole diameters. The film cooling flow and mainstream flow are at the same temperature and the film cooling is supplied through long delivery tubes. Velocity, turbulence intensity and eddy transport profiles are presented. The ratios of lateral eddy diffusivity to wall-normal eddy diffusivity values measured in this program (4-15) provide documentation of strong anisotropy of eddy transport in the flow.

Wang, L.; Tsang, H.; Simon, T.; Eckert, E. [Univ. of Minnesota, Minneapolis, MN (United States). Heat Transfer Lab.

1996-05-01

302

Potential of public transit as a transportation control measure: Case studies  

SciTech Connect

This report is the final product of the Clean Air Project of the National Association of Regional Councils/NARC. It documents a nationwide study of transit projects and programs initiated in the wake of the 1990 Clean Air Act Amendments/CAAA and the Intermodal Surface Transportation Efficiency Act of 1991/ISTEA. The study purpose was to assess the experience, limitations, and value of public transit as a potential transportation control measure/TCM, i.e., generates significant air quality benefits by eliminating or reducing emissions from motor vehicles. Four in-depth case studies and six additional projects featured as innovations in transportation are offered as examples investigating the potential of transit as a TCM. These case studies and innovations highlight the efforts of ten metropolitan areas and transit agencies which have succeed in developing and implementing innovative transit strategies.

Sillings, M.

1998-07-01

303

Measurement of Fracture Aperture Fields Using Ttransmitted Light: An Evaluation of Measurement Errors and their Influence on Simulations of Flow and Transport through a Single Fracture  

Microsoft Academic Search

Understanding of single and multi-phase flow and transport in fractures can be greatly enhanced through experimentation in transparent systems (analogs or replicas) where light transmission techniques yield quantitative measurements of aperture, solute concentration, and phase saturation fields. Here we quanti@ aperture field measurement error and demonstrate the influence of this error on the results of flow and transport simulations (hypothesized

Russell L. Detwiler; Robert J. Glass; Scott E. Pringle

1999-01-01

304

Transportation  

Microsoft Academic Search

Looking backward from the city of 1982 to the late 1950's, we are struck by the tremendous progress that has taken place in transportation. The most far-reaching changes have occurred in aviation, but equally important has been the changing urban environment which has provided a setting in which ease of movement has at last become a reality. It is this

Wilfred Owen

1957-01-01

305

Effect of using a cowl when measuring the fiber number concentration by the membrane filter method.  

PubMed

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

Kauffer, Edmond; Eypert-Blaison, Céline

2004-05-01

306

Measurement of black carbon at Syowa station, Antarctica: seasonal variation, transport processes and pathways  

NASA Astrophysics Data System (ADS)

Measurement of black carbon (BC) was carried out at Syowa station Antarctica (69° S, 39° E) from February 2004 until January 2007. The BC concentration at Syowa ranged from below detection to 176 ng m-3 during the measurements. Higher BC concentrations were observed mostly under strong wind (blizzard) conditions due to the approach of a cyclone and blocking event. The BC-rich air masses traveled from the lower troposphere of the Atlantic and Indian Oceans to Syowa (Antarctic coast). During the summer (November-February), the BC concentration showed a diurnal variation together with surface wind speed and increased in the katabatic wind from the Antarctic continent. Considering the low BC source strength in the Antarctic continent, the higher BC concentration in the continental air (katabatic wind) might be caused by long range transport of BC via the free troposphere from mid- and low- latitudes. The seasonal variation of BC at Syowa had a maximum in August, while at the other coastal stations (Halley, Neumayer, and Ferraz) and the continental station (Amundsen-Scott), the maximum occurred in October. This difference may result from different transport pathways and scavenging of BC by precipitation during the transport from the source regions. During the austral summer, long-range transport of BC via the free troposphere is likely to make an important contribution to the ambient BC concentration. The BC transport flux indicated that BC injection into the Antarctic region strongly depended on the frequency of storm (blizzard) conditions. The seasonal variation of BC transport flux increased by 290 mg m-2 month-1 in winter-spring when blizzards frequently occurred, whereas the flux decreased to lower than 50 mg m-2 month-1 in the summer with infrequent blizzards.

Hara, K.; Osada, K.; Yabuki, M.; Hayashi, M.; Yamanouchi, T.; Shiobara, M.; Wada, M.

2008-05-01

307

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

NASA Astrophysics Data System (ADS)

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.

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

2013-04-01

308

Comparison of experimental measurements and gyrokinetic turbulent electron transport models in Alcator C-Mod plasmas  

NASA Astrophysics Data System (ADS)

We present results of core turbulence measurements and associated transport in Alcator C-Mod using phase contrast imaging (PCI) diagnostic. In order to interpret and better understand the measurements we quantitatively compared the results with extensive simulations with the gyrokinetic code GYRO through a synthetic PCI diagnostic. Both L-Mode and H-Mode plasmas were examined. The L-Mode experiments were carried out over the range of densities covering the ``neo-Alcator'' (linear confinement time scaling with density) to the ``saturated ohmic'' regime. The key role played by the ion temperature gradient (ITG) turbulence has been verified by measurements of turbulent wave propagation which was dominantly in the ion diamagnetic direction in the laboratory frame. The absolute fluctuation intensity also agreed with simulation within experimental error. In the saturated ohmic and H-Mode regime where ion transport dominates, the simulated ion and electron thermal diffusivities also agree with experiments after varying the ion temperature gradient or adding ExB shear suppression within experimental uncertainty. However, in the linear ohmic regime where electron transport dominates, GYRO does not agree with experiments, showing significantly larger ion thermal transport and smaller electron thermal transport. Our study shows that although the electron temperature gradient (ETG) mode is unstable, the nonlinear simulation with k??s up to 4 does not raise the electron thermal diffusivity to the experimental level. Further work to explore even higher-k ETG regimes with GYRO is underway and the results will be presented. Work supported by U. S. DOE under DE-FG02-94-ER54235 and DE-FC02-99-ER54512.

Lin, Liang

2009-11-01

309

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

NASA Astrophysics Data System (ADS)

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).

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

1992-07-01

310

In situ measurement of solute transport in the bone lacunar-canalicular system.  

PubMed

Solute transport through the bone lacunar-canalicular system is believed to be essential for osteocyte survival and function but has proved difficult to measure. We report an approach that permits direct measurement of real-time solute movement in intact bones. By using fluorescence recovery after photobleaching, the movement of a vitally injected fluorescent dye (sodium fluorescein) among individual osteocytic lacunae was visualized in situ beneath the periosteal surface of mouse cortical bone at depths up to 50 microm with laser scanning confocal microscopy. Transport was analyzed by using a two-compartment mathematical model of solute diffusion that accounted for the characteristic anatomical features of the lacunar-canalicular system. The diffusion coefficient of fluorescein (376 Da) was determined to be 3.3 +/- 0.6 x 10(-6) cm2/sec, which is 62% of its diffusion coefficient in water and is similar to diffusion coefficients measured for comparably sized molecules in cartilage. The diffusion of fluorescein in bone is also consistent with the presence of an osteocyte pericellular matrix whose structure resembles that proposed for the endothelial glycocalyx [Squire, J. M., Chew, M., Nneji, G., Neal, C., Barry, J. & Michel, C. (2001) J. Struct. Biol. 136, 239-255]. To our knowledge, this is the first instance where the dynamics of molecular movement has been measured directly in the bone lacunar-canalicular system. This in situ imaging approach should also facilitate the analysis of convection-based transport mechanisms in bones of living animals. PMID:16087872

Wang, Liyun; Wang, Yilin; Han, Yuefeng; Henderson, Scott C; Majeska, Robert J; Weinbaum, Sheldon; Schaffler, Mitchell B

2005-08-08

311

In situ measurement of solute transport in the bone lacunar-canalicular system  

PubMed Central

Solute transport through the bone lacunar-canalicular system is believed to be essential for osteocyte survival and function but has proved difficult to measure. We report an approach that permits direct measurement of real-time solute movement in intact bones. By using fluorescence recovery after photobleaching, the movement of a vitally injected fluorescent dye (sodium fluorescein) among individual osteocytic lacunae was visualized in situ beneath the periosteal surface of mouse cortical bone at depths up to 50 ?m with laser scanning confocal microscopy. Transport was analyzed by using a two-compartment mathematical model of solute diffusion that accounted for the characteristic anatomical features of the lacunar-canalicular system. The diffusion coefficient of fluorescein (376 Da) was determined to be 3.3 ± 0.6 × 10-6 cm2/sec, which is 62% of its diffusion coefficient in water and is similar to diffusion coefficients measured for comparably sized molecules in cartilage. The diffusion of fluorescein in bone is also consistent with the presence of an osteocyte pericellular matrix whose structure resembles that proposed for the endothelial glycocalyx [Squire, J. M., Chew, M., Nneji, G., Neal, C., Barry, J. & Michel, C. (2001) J. Struct. Biol. 136, 239–255]. To our knowledge, this is the first instance where the dynamics of molecular movement has been measured directly in the bone lacunar-canalicular system. This in situ imaging approach should also facilitate the analysis of convection-based transport mechanisms in bones of living animals.

Wang, Liyun; Wang, Yilin; Han, Yuefeng; Henderson, Scott C.; Majeska, Robert J.; Weinbaum, Sheldon; Schaffler, Mitchell B.

2005-01-01

312

An estimation of the effective number of electrons contributing to the coordinate measurement with a TPC: II  

NASA Astrophysics Data System (ADS)

For time projection chambers (TPCs) the accuracy in measurement of the track coordinates along the pad-row direction deteriorates with the drift distance (z): ?X2˜D2·z/Neff, where D is the diffusion constant and Neff is the effective number of electrons. Experimentally it has been shown that Neff is smaller than the average number of drift electrons per pad row (). In the previous work we estimated Neff by means of a simple numerical simulation for argon-based gas mixtures, taking into account the diffusion of electrons only in the pad-row direction (Kobayashi, 2006 [1]). The simulation showed that Neff could be as small as ˜ 30% of because of the combined effect of statistical fluctuations in the number of drift electrons (N) and in their multiplication in avalanches. In this paper, we evaluate the influence of the diffusion normal to the pad-row direction on the effective number of electrons. The de-clustering of the drift electrons due to the diffusion makes Neff drift-distance dependent. However, its effect was found to be too small to explain the discrepancy between the values of Neff measured with two TPC prototypes different in size.

Kobayashi, Makoto

2013-11-01

313

A measurement of the muon number in showers using inclined events detected at the Pierre Auger Observatory  

NASA Astrophysics Data System (ADS)

The average muon content of measured showers with zenith angles between 62? and 80? detected at the Pierre Auger Observatory is obtained as a function of shower energy using a reconstruction method specifically designed for inclined showers and the hybrid character of the detector. The reconstruction of inclined showers relies on a comparison between the measured signals at ground and reference patterns at ground level from which an overall normalization factor is obtained. Since inclined showers are dominated by muons this factor gives the relative muon size. It can be calibrated using a subsample of showers simultaneously recorded with the fluorescence detector (FD) and the surface detector (SD) which provides an independent calorimetric measurement of the energy. The muon size obtained for each shower becomes a measurement of the relative number of muons with respect to the reference distributions. The precision of the measurement is assessed using simulated events which are reconstructed using exactly the same procedure. We compare the relative number of muons versus energy as obtained to simulations. Proton simulations with QGSJETII show a factor of 2.13 ± 0.04(stat) ± 0.11(sys) at 1019eV without significant variations in the energy range explored between 4 × 1018eV to 7 × 1019eV. We find that none of the current shower models, neither for proton nor for iron primaries, are able to predict as many muons as are observed.

Rodriguez, G.

2013-06-01

314

Determining the Number of State Psychiatric Hospital Beds by Measuring Quality of Care with Artificial Neural Networks  

Microsoft Academic Search

This study uses a new paradigm to calculate the min imum and the optimum number of involuntary psychi atric beds at a state hospital in Maine with 5538 admissions over a 7-year period. The method measures quality of care (Q) based upon the accuracy of predic tion of length-of-stay for the hospital, and of commu nity length-of-stay for the community,

George E. Davis; Walter E. Lowell; Geoffrey L. Davis

1998-01-01

315

Simultaneous Raman and electrical transport measurements of disordered graphene in situ in ultra-high vacuum  

NASA Astrophysics Data System (ADS)

Resonant Raman scattering in graphene gives unique information about disorder, as the D peak is observed only in the presence of disorder which produces intervalley scattering of the electrons. The nature of disorder in graphene prepared by various techniques and on various substrates of the subject of significant research, with significant attention being paid to scattering by charged impurities; resonant scatterers due to vacancies, chemisorbed impurities, etc.; and non-resonant short-range impurities. In order to study the effect of these types of disorder on graphene's electronic properties and Raman spectra simultaneously, we have developed a facility combining thermal deposition, ion bombardment, electrical transport and micro-Raman measurements in an ultra high vacuum environment. We will discuss the capabilities of this facility and present the results of Raman and electrical transport measurements on controllably disordered graphene.

Tosado, Jacob; Ballarotto, Vince; Cullen, William G.; Fuhrer, Michael S.

2012-02-01

316

Measurement of gas transport through fiber preforms and densified composites for chemical vapor infiltration  

Microsoft Academic Search

Gas transport via pressure-driven permeation or via concentration-driven diffusion is a key step in the chemical vapor infiltration (CVI) process. This paper describes methods for the measurement of these properties 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 three-dimensional (3-D) weave composite. The

T. L. Starr; N. Hablutzel

1998-01-01

317

Measurement of Thermal Transport Properties with an Improved Transient Plane Source Technique  

Microsoft Academic Search

The transient plane source (TPS) technique has been revised with the aim of developing a simple and fast system to measure the thermal transport properties of materials at low temperatures, especially high-Tc superconductors. To ensure reliable results, any new system should be tested with known samples. Fused silica, 0.9% carbon steel (215\\/3), and halide crystals (silver chloride) were studied with

M. Anis-ur-Rehman; A. Maqsood

2003-01-01

318

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

Microsoft Academic Search

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

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

1998-01-01

319

Measurement of Interfacial Area Transport in Oil-water Dispersed Flow by Double-sensor Probe  

Microsoft Academic Search

The double-sensor conductivity probe was designed and applied to measure the distribution and transport characteristics of the oil-water dispersed flow in a vertical upward pipe. Typical radial profiles of interfacial area concentration, oil phase fraction, interfacial velocity, and oil drop Sauter mean diameter were obtained at four axial locations from the test section entrance of z\\/D =8.75, 33.75, 58.5 and

Dongjian Zhao; Xiaowei Hu; Liejin Guo; Ximin Zhang

2007-01-01

320

In situ measurements of advective solute transport in permeable shelf sands  

Microsoft Academic Search

Solute transport rates within the uppermost 2cm of a rippled continental shelf sand deposit, with a mean grain size of 400–500?m and permeabilities of 2.0–2.4×10?11m2, have been measured in situ by detecting the breakthrough of a pulse of iodide after its injection into the bottom water. These tracer experiments were conducted on the USA Middle Atlantic Bight shelf at a

Clare E. Reimers; Hilmar A. Stecher; Gary L. Taghon; Charlotte M. Fuller; Markus Huettel; Antje Rusch; Natacha Ryckelynck; Christian Wild

2004-01-01

321

Electrical transport measurements and electronic structure calculations on doped half-Heusler FeVSb  

Microsoft Academic Search

Structural and electrical transport properties of pure and doped FeVSb half-Heusler phases were investigated from X-ray diffraction, Mossbauer spectroscopy, resistivity and thermopower measurements. The doping elements were Ti, Zr, Mn and Co. Electronic structures calculations of experimental samples were carried out using Korringa-Kohn-Rostoker coherent potential approximation (KKR-CPA) method within the LDA framework. We observed that the room temperature Seebeck coefficient

L. Jodin; J. Tobola; P. Pecheur; H. Scherrer

2001-01-01

322

Airborne High Spectral Resolution Lidar Aerosol Measurements and Comparisons with Transport Models  

Microsoft Academic Search

The NASA Langley Research Center (LaRC) airborne High Spectral Resolution Lidar (HSRL) measured aerosol distributions and optical properties during several field experiments in 2006 and 2007. These experiments include: 1) the joint Megacity Initiative: Local and Global Research Observations (MILAGRO) \\/Megacity Aerosol Experiment in Mexico City (MAX-MEX)\\/Intercontinental Chemical Transport Experiment-B (INTEX B) experiment, 2) the Texas Air Quality Study (TEXAQS)\\/Gulf

R. Ferrare; C. Hostetler; J. Hair; A. Cook; D. Harper; S. Burton; M. Obland; R. Rogers; L. Kleinman; A. Clarke; J. Fast; M. Chin; G. Carmichael; Y. Tang; L. Emmons; B. Pierce; C. Kittaka

2007-01-01

323

Vacuolar Chloride Transport in Mesembryanthemum crystallinum L. Measured Using the Fluorescent Dye Lucigenin  

Microsoft Academic Search

.   To study vacuolar chloride (Cl?) transport in the halophilic plant Mesembryanthemum crystallinum L., Cl? uptake into isolated tonoplast vesicles was measured using the Cl?-sensitive fluorescent dye lucigenin (N,N?-dimethyl-9,9?-bisacridinium dinitrate). Lucigenin was used at excitation and emission wavelengths of 433 nm and 506 nm,\\u000a respectively, and showed a high sensitivity towards Cl?, with a Stern-Volmer constant of 173 m\\u000a \\u000a ?1

F. Wissing; J. A. C. Smith

2000-01-01

324

Sediment transport time measured with U-Series isotopes: Resultsfrom ODP North Atlantic Drill Site 984  

SciTech Connect

High precision uranium isotope measurements of marineclastic sediments are used to measure the transport and storage time ofsediment from source to site of deposition. The approach is demonstratedon fine-grained, late Pleistocene deep-sea sediments from Ocean DrillingProgram Site 984A on the Bjorn Drift in the North Atlantic. The sedimentsare siliciclastic with up to 30 percent carbonate, and dated by sigma 18Oof benthic foraminifera. Nd and Sr isotopes indicate that provenance hasoscillated between a proximal source during the last three interglacialperiods volcanic rocks from Iceland and a distal continental sourceduring glacial periods. An unexpected finding is that the 234U/238Uratios of the silicate portion of the sediment, isolated by leaching withhydrochloric acid, are significantly less than the secular equilibriumvalue and show large and systematic variations that are correlated withglacial cycles and sediment provenance. The 234U depletions are inferredto be due to alpha-recoil loss of234Th, and are used to calculate"comminution ages" of the sediment -- the time elapsed between thegeneration of the small (<_ 50 mu-m) sediment grains in the sourceareas by comminution of bedrock, and the time of deposition on theseafloor. Transport times, the difference between comminution ages anddepositional ages, vary from less than 10 ky to about 300 to 400 ky forthe Site 984A sediments. Long transport times may reflect prior storagein soils, on continental shelves, or elsewhere on the seafloor. Transporttime may also be a measure of bottom current strength. During the mostrecent interglacial periods the detritus from distal continental sourcesis diluted with sediment from Iceland that is rapidly transported to thesite of deposition. The comminution age approach could be used to dateQuaternary non-marine sediments, soils, and atmospheric dust, and may beenhanced by concomitant measurement of 226Ra/230Th, 230Th/234U, andcosmogenic nuclides.

DePaolo, Donald J.; Maher, Kate; Christensen, John N.; McManus,Jerry

2006-06-05

325

IR detector for hydrocarbons concentration measurement in emissions during petroleum and oil products storage and transportation  

NASA Astrophysics Data System (ADS)

A double beam IR detector is developed for light hydrocarbons concentration measurement in emissions from storage vessels during oil and oil products storage and transportation. It was concluded on the basis of chromatogram that main crude losses from evaporation are the share of hydrocarbons light ends from methane to decane. Detector operation is based on spectral transparency measurement in the infrared spectra absorption range. Operational wavelength of infrared radiation makes 3.4 ?m. measurement principle is based on concentration calculation proceed from molecule absorption cross-section, optical path length between light emitted diode and reference and signal photodiodes as well as from value of measured signal transmitted through gaging volume. The novel of offering device is an actual paraffin hydrocarbons concentration measurement in emissions and continuous and automatic environment quality control.

Vasilyev, Andrey O.; Shemanin, Valeriy G.; Chartiy, Pavel V.

2011-09-01

326

Clock-transport synchronisation for neutrino time-of-flight measurements  

NASA Astrophysics Data System (ADS)

A method to synchronise, at the sub-nanosecond level, clocks used for neutrino time-of-flight measurements is proposed. Clocks situated near the neutrino source and target are compared with a moveable clock that is transported between them. The general-relativistic theory of the procedure was tested and verified in an experiment performed by Hafele and Keating in 1972. It is suggested that use of such a synchronisation method may contribute to a precise test of the Sagnac effect—a measured velocity greater than c—for neutrinos of the proposed LBNE beam between Fermilab and the Homestake mine.

Field, J. H.

2012-11-01

327

How to Measure Drug Transport across the Blood-Brain Barrier  

PubMed Central

Summary: The extent to which a substance in the circulation gains access to the CNS needs to be determined for potential neuropharmaceuticals as well as for drug candidates with primary targets in the periphery. Characteristics of the in vivo methods, ranging from classical pharmacokinetic techniques (intravenous administration and tissue sampling) over brain perfusions to microdialysis and imaging techniques, are highlighted. In vivo measurements remain unmatched with respect to sensitivity and for the characterization of carrier-mediated uptake, receptor-mediated transport, and active efflux. Isolated microvessels are valuable tools for molecular characterization of transporters. Endothelial cell culture models of the blood-brain barrier (BBB) are pursued as in vitro systems suitable for screening procedures. Recent applications of conditionally immortalized cell lines indicate that a particular weakness of culture models because of downregulation of BBB-specific transporter systems can be overcome. In silico approaches are being developed with the goal of predicting brain uptake from molecular structure at early stages of drug development. Currently, the predictive capability is limited to passive, diffusional uptake and predominantly relies on few molecular descriptors related to lipophilicity, hydrogen bonding capacity, charge, and molecular weight. A caveat with most present strategies is their reliance on surrogates of BBB transport, like CNS activity/inactivity or brain-to-blood partitioning rather than actual BBB permeability data.

Bickel, Ulrich

2005-01-01

328

Investigating Changes in Flow and Transport Properties due to Bio-clogging of Porous Media from Complex Conductivity Measurements  

NASA Astrophysics Data System (ADS)

Complex conductivity measurements (0.1-1000 Hz) were obtained in flow through sand columns inoculated with Pseudomonas aeruginosa to simulate the effect of bio-clogging on the flow and transport properties of sands. Pressure transducers installed along the side of the columns were used to monitor the changes in hydraulic conductivity. Evidence of bio-clogging was obtained from temporal biomass growth, scanning electron microscope (SEM) observations, and temporal changes in flow rate. After week one of the experiment, the inoculated sand columns showed an increase in the imaginary conductivity component concurrent with a reduction in hydraulic conductivity, a decrease in flow rate and an increase in microbial cell numbers. SEM images showed microbial cells attached to sand grains and polysaccharides joining two or more sand grains together. Analysis of breakthrough curves (BTCs) from dye tracer test conducted at the beginning and the end of the experiment showed a reduction of the porosity and the dispersion coefficient from the initial values by 16% and 50%, respectively. Empirical equations involving formation factor and imaginary conductivity component was used to calculate the hydraulic conductivity. Good agreement was obtained between the calculated hydraulic conductivity from the complex conductivity measurements and the hydraulic conductivity measured along the side of the sand columns. The increase in imaginary conductivity component can be explained by constriction of pores and narrowing of pore throats due to microbial growth and biofilm formation in the sand columns. The results of this study highlights the potential of complex conductivity measurements to validate bioclogging models used to assess the effect of biomass growth on the flow and transport properties of porous media.

Abdel Aal, G.; Atekwana, E. A.

2009-05-01

329

[The number needed to treat as a measure of effect in the treatment of primary immune thrombocytopenia].  

PubMed

In randomized or comparative studies, when the outcomes are binary or dichotomous, the effect of a specific treatment can be reported using the absolute risk reduction (ARR) and the number needed to treat (NNT), which is the reciprocal of the ARR (1/ARR = NNT). The objective of the present study was to realize a review of the different modalities of treatment of primary immune thrombocytopenia (ITP), using as effect measurement the calculation of the ARR and NNT and their confidence intervals (CI 95%). The number needed to harm (NNH) can be calculated with the same formula of NNT, taking in account only the adverse events (CTCAE scale) of the treatment in relation with those in the control group. The results showed the effect of different types of treatment of ITP. The NNT was better in randomized studies than those of inferior design. The NNH calculation showed the safe level of the intervention. It can be observed that age (youth) and no splenectomy condition exhibited some influence in the favorable NNT report. In conclusion, given the advantages of the ARR and the NNT for clinical decision making, it can be suggested that these measurements of effect should also be reported, in addition to other statistical measurements for ITP treatment or any observational study with dichotomous or binary outcomes. PMID:22524105

Vizcaíno, Gilberto; Vizcaíno-Carruyo, Jennifer

2012-03-01

330

Analysis of free carrier absorption measurement of electronic transport properties of silicon wafers  

NASA Astrophysics Data System (ADS)

Sensitivity analysis of electronic transport property measurement of silicon wafers with modulated free carrier absorption (MFCA) technique and multi-parameter fitting procedure is performed. The sensitivity of the multi-parameter estimate employing the dependences of the MFCA amplitude and phase on the pump-probe-beam separation measured at several modulation frequencies covering an appropriate range is theoretically compared with that employing only the dependences of the MFCA amplitude and phase on the modulation frequency. Simulation results show that the dependences of the MFCA amplitude and phase on the pump-probe beam separation are more sensitive to the electronic transport properties of silicon wafers than the frequency dependences. The electronic transport properties of the silicon wafers determined with the two-beam separation dependence are therefore more accurate than that determined with the frequency dependence. Comparative experiments with a silicon wafer are performed and the carrier lifetime, the carrier diffusivity, and the front surface recombination velocity are determined simultaneously and unambiguously with both techniques.

Zhang, X.; Li, B.; Gao, C.

2008-01-01

331

A wide number of trials is required to achieve acceptable reliability for measurement patellar tendon elongation in vivo.  

PubMed

The purpose of the current study was to examine the reproducibility of patellar tendon elongation measurements using brightness-mode ultrasonography (BMU) during isometric knee extension contractions. We hypothesized that the measurement of the patellar tendon elongation during only one maximal voluntary isometric knee extension contractions would not provide reliable results and that a wide number of trials is required to achieve acceptable reliability. Ten participants (eight male and two female) performed 10 isometric knee extension contractions on two separate days (5 trials on each day). Using a modified knee brace, the ultrasound probe was firmly adjusted in the sagittal plane overlying the patellar tendon. The registered ultrasound images were analyzed by three different but equally trained observers. The reproducibility was examined by the calculation of the within-day, between-day and overall coefficient of multiple correlations (wCMC, bCMC and oCMC). The Spearman-Brown prophecy formula was use to estimate the required trials to achieve the desired reliability. The wCMC, bCMC and oCMC were in average 0.824, 0.798 and 0.770, respectively, suggesting a rather moderate reproducibility of patellar tendon elongation measurements. For a high reliability (?0.95) of tendon elongation measurements 5-6 trials are required. Finally, the results revealed an independence of the measurements from days and observers. PMID:22178032

Schulze, Felix; Mersmann, Falk; Bohm, Sebastian; Arampatzis, Adamantios

2011-12-16

332

Measurement of total acid number (TAN) and TAN boiling point distribution in petroleum products by electrospray ionization mass spectrometry.  

PubMed

We report a new method for rapid measurement of total acid number (TAN) and TAN boiling point (BP) distribution for petroleum crude and products. The technology is based on negative ion electrospray ionization mass spectrometry (ESI-MS) for selective ionization of petroleum acid and quantification of acid structures and molecular weight distributions. A chip-based nanoelectrospray system enables microscale (<200 mg) and higher throughput (20 samples/h) measurement. Naphthenic acid structures were assigned based on nominal masses of a set of predefined acid structures. Stearic acid is used as an internal standard to calibrate ESI-MS response factors for quantification purposes. With the use of structure-property correlations, boiling point distributions of TAN values can be calculated from the composition. The rapid measurement of TAN BP distributions by ESI is demonstrated for a series of high-TAN crudes and distillation cuts. TAN values determined by the technique agree well with those by the titration method. The distributed properties compare favorably with those measured by distillation and measurement of TAN of corresponding cuts. PMID:18179248

Qian, Kuangnan; Edwards, Kathleen E; Dechert, Gary J; Jaffe, Stephen B; Green, Larry A; Olmstead, William N

2008-01-08

333

Measurements and modelling of molecular iodine emissions, transport and photodestruction in the coastal region around Roscoff  

NASA Astrophysics Data System (ADS)

Emissions from the dominant six macroalgal species in the coastal regions around Rosccoff, France, have been modelled to support the Reactive Halogens in the Marine Boundary Layer Experiment (RHaMBLE) campaign undertaken in September 2006. A 2-D model was used to explore the relationship between point and line measurements of molecular iodine concentrations, and total regional emissions, based on seaweed I2 emission rates measured in the laboratory. The relatively simple modelling technique has produced modelled point and line data, which compare quantitatively with campaign measurements, and provide a link between emission fields and the different measurement geometries used to quantify atmospheric I2 concentrations during RHaMBLE. During nightime, absolute concentrations in the region of 5 pptv are predicted and measured in the LP-DOAS measurements, with site concentrations predicted and measured up to 40 pptv, compatible with concentrations above Laminariales beds of approximately 2.5 ppbv. Daytime measured concentrations of I2 at site correlate with modelled production and transport processes, however complete recycling of photodissociated I2 is required in the model to quantitatively match measured concentrations. Additional local source terms are suggested to provide a feasible mechanism to account for this discrepancy.Total of I2 emissions over the 100 km2 region around Roscoff are calculated as 1.5×1019 molecules per second during the lowest tides.

Leigh, R. J.; Ball, S. M.; Whitehead, J.; Leblanc, C.; Shillings, A. J. L.; Mahajan, A. S.; Oetjen, H.; Dorsey, J. R.; Gallagher, M.; Jones, R. L.; Plane, J. M. C.; Potin, P.; McFiggans, G.

2009-10-01

334

Airborne lidar measurements of pollution transport in central and southern California during CalNEX 2010  

NASA Astrophysics Data System (ADS)

During the CalNEX experiment from May through July 2010, we co-deployed NOAA’s airborne ozone and aerosol lidar TOPAZ and the University of Leeds scanning Doppler wind lidar on a Twin Otter aircraft. We flew a total of 46 missions over central and southern California, focusing primarily on the Los Angeles Basin and Sacramento areas. The downward-looking lidars provided highly resolved measurements of ozone concentration, aerosol backscatter, and wind speed and direction in the boundary layer and lower free troposphere. We will use the airborne lidar data to characterize transport of ozone and aerosols on regional and local scales. In particular, we will focus on pollutant transport between air basins and the role of flow patterns in complex terrain, such as gap flows and orographic lifting and venting along mountain slopes, on pollutant distribution.

Senff, C. J.; Alvarez, R. J., II; Hardesty, R.; Langford, A. O.; Banta, R. M.; Brewer, A.; Davies, F.; Sandberg, S.; Marchbanks, R.; Weickmann, A.

2010-12-01

335

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

SciTech Connect

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.

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

336

Double-injection current transients as a way of measuring transport in insulating organic films  

NASA Astrophysics Data System (ADS)

We propose a double-injection current transient technique for the study of charge-carrier transport in thin insulating films of low-mobility materials with reduced carrier bimolecular recombination compared to the Langevin type. This experimentally simple technique, allows us to estimate the sum of the faster carrier and the slower carrier mobility's (?f+?s) and the slower carrier mobility (?s). Furthermore, in thin films when the RC current overlaps the injection current transients we propose to estimate these transport parameters using the extracted charge as a function of injection pulse duration. The method is applied on bulk-heterojunction solar cells made from blends of regioregular poly(3-hexylthiophene) and 1-(3-methoxycarbonyl)propyl-1-phenyl-[6,6]-methanofullerene. We have experimentally verified the technique by measuring the charge carrier mobility's and compared them with results obtained using standard time-of-flight and carrier extraction using linearly increasing voltage techniques.

Juška, G.; Genevi?ius, K.; Sliaužys, G.; Pivrikas, A.; Scharber, M.; Österbacka, R.

2007-06-01

337

Magneto-optical setup for in situ strain and transport measurements on superconductors  

NASA Astrophysics Data System (ADS)

A recently developed magneto-optical (MO) imaging setup for investigations on superconductors is reported. The main originality of our setup is its ability to combine both strain and transport measurements in the temperature range of 6-300 K with magneto-optical observations. We give here some theoretical considerations on the cryostat conception, which is a key point of our setup. In particular, the thermal and mechanical aspects are discussed. A detailed description of the MO setup and of the associated strain apparatus is given. Additionally, an example of MO strain and transport study on DyBCO coated conductors is given. Evidence of Luders Bands formation under strain in the Hastelloy® is revealed by the field penetration inside cracks in the DyBCO and MgO layers. A correlation between the damaging morphology and the critical current at 70 K versus strain has been established.

Villaume, A.; Antonevici, A.; Bourgault, D.; Leggeri, J. P.; Porcar, L.; Villard, C.

2008-02-01

338

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

SciTech Connect

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.

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

339

Evaluation and monitoring of transportation control measures. Final research report, September 1991-September 1995  

SciTech Connect

The mandates of the Clean Air Act Amendments (CAAAs) and Intermodal Surface Transportation Efficiency Act (ISTEA) Congestion Mitigation and Air Quality (CMAQ) Improvement Program require the evaluation and monitoring of transportation control measure (TCM) emission impacts. The objective of the research documented herein was to investigate issues related to the evaluation and monitoring of TCM impacts. Researchers reviewed the advantages and limitations of TCM evaluation methods currently available, and identified two critical issues which influence their capabilities and accuracy. The TCM evaluation methods reviewed include the use of comparative empirical data, network-based models, and sketch-planning tools. The structure of TCM monitoring programs was also studied. Monitoring programs are presented for four TCMs: transit plazas, intersection improvements, ridesharing, and park-and-ride lots.

Knapp, K.K.; Rao, K.S.; Crawford, J.A.; Krammes, R.A.

1995-09-01

340

Translating the Overall Equipment Effectiveness Measure From the Lean Manufacturing Paradigm to the Road Freight Transport Industry  

Microsoft Academic Search

Effective performance hinges around what is measured. Many benchmarks have been produced, which measure the effectiveness of discrete elements of road freight transport. However, no one, overall, aggregate measure has been devised, which assesses the total effectiveness of vehi cles for the industry. This paper identifies some of the benefits of establishing such a measure, explores how it could be

Robert Mason; David Simons; Bernard Gardner

341

Comparison of energy transport measurements and computer simulations in a single module prototype for PBFA 2  

NASA Astrophysics Data System (ADS)

The 36-module Particle Beam Fusion Accelerator (PBFA II) is designed to provide a 30 MV pulse, with greater than 150 TW, to a centrally located lithium ion diode. Each module is driven by a 6 MV, 400 kJ Marx generator and uses three water-insulated and switched pulse compression stages followed by a voltage inversion-adder unit. All impedance matching transmissioin-line transformer couples the output pulse from the inversion-adder unit to the central vacuum insulator, plasma erosion switches, and ion diode. The prototype of a single PBFA-II module, called Demon, is being used to test component design, including a mock-up of a section of the vacuum insulator, and to determine overall module operating characteristics. The results of measurements of energy transport efficiencies through the successive pulse compression stages are presented. Results of energy transport measurements on an 18 module, one-fifth scale model, are also compared to the single-line data. A comparison of measured parameters with computer circuit code simulations of the hardware design is also included. Comparisons are used to suggest areas of possible improvements. The measured module output characteristics agree with the code simulations and meet the design requirements for the PBFA-II accelerator.

Neau, E. L.; Seamen, J. F.; Bloomquist, D. D.; Babcock, S. R.; Schneider, L. X.; Sujka, B. R.

342

A Fluorescence Method for Measurement of Glucose Transport in Kidney Cells  

PubMed Central

Abstract Background Diabetes may alter renal glucose reabsorption by sodium (Na+)-dependent glucose transporters (SGLTs). Radiolabeled substrates are commonly used for in vitro measurements of SGLT activity in kidney cells. We optimized a method to measure glucose uptake using a fluorescent substrate, 2-(N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino)-2-deoxyglucose (2-NBDG). Methods Uptake buffers for 2-NBDG were the same as for 14C-labeled ?-methyl-d-glucopyranoside ([14C]AMG). Cell lysis buffer was optimized for fluorescence of 2-NBDG and Hoechst DNA stain. Uptake was performed on cultures of primary mouse kidney cells (PMKCs), the LLC-PK1 proximal tubule cell line, or COS-7 cells transiently overexpressing mouse SGLT1 or SGLT2 by incubating cells at 37°C in buffer containing 50–200??M 2-NBDG. Microscopy was performed to visualize uptake in intact cells, while a fluorescence microplate reader was used to measure intracellular concentration of 2-NBDG ([2-NBDG]i) in cell homogenates. Results Fluorescent cells were observed in cultures of PMKCs and LLC-PK1 cells exposed to 2-NBDG in the presence or absence of Na+. In LLC-PK1 cells, 2-NBDG transport in the presence of Na+ had a maximum rate of 0.05?nmol/min/?g of DNA. In these cells, Na+-independent uptake of 2-NBDG was blocked with the GLUT inhibitor, cytochalasin B. The Na+-dependent uptake of 2-NBDG decreased in response to co-exposure to the SGLT substrate, AMG, and it could be blocked with the SGLT inhibitor, phlorizin. Immunocytochemistry showed overexpression of SGLT1 and SGLT2 in COS-7 cells, in which, in the presence of Na+, [2-NBDG]i was fivefold higher than in controls. Conclusion Glucose transport in cultured kidney cells can be measured with the fluorescence method described in this study.

Blodgett, Amy B.; Kothinti, Rajendra K.; Kamyshko, Ivan; Petering, David H.; Kumar, Suresh

2011-01-01

343

Measuring Molecular Motor Forces In Vivo: Implications for Tug-of-War Models of Bidirectional Transport  

PubMed Central

Molecular motor proteins use the energy released from 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 methodology capable of making precise in vivo stall-force measurements of individual cargoes hauled by molecular motors in their native environment. Despite routine measurement of motor forces in vitro, performing and calibrating such measurements in vivo has been challenging. We describe the methodology recently developed to overcome these difficulties, and used to measure stall forces of both kinesin-1 and cytoplasmic dynein-driven lipid droplets in Drosophila embryos. Critically, by measuring the cargo dynamics in the optical trap, we find that there is memory: it is more likely for a cargo to resume motion in the same direction—rather than reverse direction—after the motors transporting it detach from the microtubule under the force of the optical trap. This suggests that only motors of one polarity are active on the cargo at any instant in time and is not consistent with the tug-of-war models of bidirectional transport where both polarity motors can bind the microtubules at all times. We further use the optical trap to measure in vivo the detachment rates from microtubules of kinesin-1 and dynein-driven lipid droplets. Unlike what is commonly assumed, we find that dynein’s but not kinesin’s detachment time in vivo increases with opposing load. This suggests that dynein’s interaction with microtubules behaves like a catch bond.

Leidel, Christina; Longoria, Rafael A.; Gutierrez, Franciso Marquez; Shubeita, George T.

2012-01-01

344

Dataverktoy for Beregning av Samfunnsokonomisk Nytte av Godstiltak. Forprosjekt. (Software for Cost-Benefit Analysis of Freight Transport Improvement Measures.)  

National Technical Information Service (NTIS)

We have developed a first draft version of a tool to compute the economic benefits of measures to enhance the efficiency of the freight transport system. This is based on results from the Norwegian national model system for freight transport, composed of ...

A. Madslien H. Minken

2011-01-01

345

First Measurements of Neutral Atmospheric Cluster and 1–2 nm Particle Number Size Distributions During Nucleation Events  

SciTech Connect

Recent observations throughout the atmosphere have shown that nucleation occurs frequently (Kulmala et al. 2004). Modeling studies and observations have shown that nucleated particles contribute significantly to concentrations of cloud condensation nuclei (Spracklen et al. 2008), thereby affecting climate (IPCC 2007). Size-resolved measurements extending down to molecular dimensions can provide information on processes that lead to nucleation and would enable development and verification of theories for particle nucleation and growth in the atmosphere and other aerosol systems. This article describes measurements of the complete number size distribution, spanning the size range from vapor molecules and molecular clusters to submicrometer particles, during atmospheric nucleation events. The measurements used two new instruments, the cluster chemical ionization mass spectrometer (Cluster CIMS) and the DEG SMPS. The Cluster CIMS measures neutral molecular clusters from 50 to 900 amu. The DEG SMPS is a scanning mobility particle spectrometer (SMPS) equipped with a diethylene glycol (DEG)-based condensation particle counter (CPC) capable of 1.1 nm mobility diameter particle detection, and overlapping the sizes detected by the Cluster CIMS (Iida et al. 2009; Jiang et al. 2011). The Cluster CIMS distinguishes neutral clusters from ions formed by ion-induced clustering by varying the reaction time for ions with the sampled air (Zhao et al. 2010). It distinguishes clusters from high molecular weight gases by measuring the incremental signal at a specified mass detected during nucleation events. The clusters that were measured in this study contain sulfuric acid, which is known to participate in atmospheric nucleation (Kuang et al. 2008).

Jiang, J.; Kuang, C.; Zhao, J.; Chen, M.; Eisele, F. L.; Scheckman, J.; Williams, B. J.; McMurry, P. H.

2011-02-01

346

Time-of-flight measurements and vertical transport in a high electron-mobility polymer  

NASA Astrophysics Data System (ADS)

We investigate charge transport in a high-electron mobility polymer, poly(N,N-bis 2-octyldodecyl-naphthalene-1,4,5,8-bis dicarboximide-2,6-diyl-alt-5,5-2,2-bithiophene) [P(NDI2OD-T2), Polyera ActivInk™ N2200]. Time-of-flight measurements reveal electron mobilities approaching those measured in field-effect transistors, the highest ever recorded in a conjugated polymer using this technique. The modest temperature dependence and weak dispersion of the transients indicate low energetic disorder in this material. Steady-state electron-only current measurements reveal a barrier to injection of about 300 meV. We propose that this barrier is located within the P(NDI2OD-T2) film and arises from molecular orientation effects.

Blakesley, James C.; Schubert, Marcel; Steyrleuthner, Robert; Chen, Zhihua; Facchetti, Antonio; Neher, Dieter

2011-10-01

347

Active Transportation Measurement and Benchmarking Development: New Orleans State of Active Transportation Report 2010-2011, Part 2.  

National Technical Information Service (NTIS)

Over the last decade, there has been a surge in bicycle and pedestrian use in communities that have invested in active transportation infrastructure and programming. While these increases show potentially promising trends, many of the cities that have sho...

B. Fields

2012-01-01

348

Thermal transport in CO2 laser irradiated fused silica: in situ measurements and analysis  

SciTech Connect

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.

Yang, S T; Matthews, M J; Elhadj, S; Draggoo, V G; Bisson, S E

2009-07-07

349

A digitally configurable measurement platform using audio cards for high-resolution electronic transport studies  

NASA Astrophysics Data System (ADS)

We report on a software-defined digitally configurable measurement platform for determining electronic transport properties in nanostructures with small readout signals. By using a high-resolution audio analog-to-digital/digital-to-analog converter in a digitally compensated bridge configuration we significantly increase the measurement speed compared to established techniques and simultaneously acquire large and small signal characteristics. We characterize the performance (16 bit resolution, 100 dB dynamic range at 192 kS/s) and demonstrate the application of this measurement platform for studying the transport properties of spin-valve nanopillars, a two-terminal device that exhibits giant magnetoresistance and whose resistance can be switched between two levels by applied magnetic fields and by currents applied by the audio card. The high resolution and fast sampling capability permits rapid acquisition of deep statistics on the switching of a spin-valve nanopillar and reduces the time to acquire the basic properties of the device - a state-diagram showing the magnetic configurations as function of applied current and magnetic field - by orders of magnitude.

Gopman, D. B.; Bedau, D.; Kent, A. D.

2012-05-01

350

A digitally configurable measurement platform using audio cards for high-resolution electronic transport studies.  

PubMed

We report on a software-defined digitally configurable measurement platform for determining electronic transport properties in nanostructures with small readout signals. By using a high-resolution audio analog-to-digital/digital-to-analog converter in a digitally compensated bridge configuration we significantly increase the measurement speed compared to established techniques and simultaneously acquire large and small signal characteristics. We characterize the performance (16 bit resolution, 100 dB dynamic range at 192 kS/s) and demonstrate the application of this measurement platform for studying the transport properties of spin-valve nanopillars, a two-terminal device that exhibits giant magnetoresistance and whose resistance can be switched between two levels by applied magnetic fields and by currents applied by the audio card. The high resolution and fast sampling capability permits rapid acquisition of deep statistics on the switching of a spin-valve nanopillar and reduces the time to acquire the basic properties of the device - a state-diagram showing the magnetic configurations as function of applied current and magnetic field - by orders of magnitude. PMID:22667635

Gopman, D B; Bedau, D; Kent, A D

2012-05-01

351

The application of electrical resistance measurements to water transport in lime-masonry systems  

NASA Astrophysics Data System (ADS)

The paper describes an experimental determination of impedance spectroscopy derived resistance measurements to record water transport in lime-masonry systems. It strongly supports the use of Sharp Front theory and Boltzmann's distribution law of statistical thermodynamics to corroborate the data obtained. A novel approach is presented for the application of impedance measurements to the water transport between freshly mixed mortars and clay brick substrates. Once placed, fresh mortar is dewatered by brick and during this time the volume fraction water content of the mortar is reduced. An equation is derived relating this change in water content to the bulk resistance of the mortar. Experimental measurements on hydraulic lime mortars placed in contact with brick prisms confirm the theoretical predictions. Further, the results indicate the time at which dewatering of a mortar bed of given depth is completed. The technique has then potential to be applied for in situ monitoring of dewatering as a means of giving insight into the associated changes in mechanical and chemical properties.

Ball, R. J.; Allen, G. C.; Carter, M. A.; Wilson, M. A.; Ince, C.; El-Turki, A.

2012-03-01

352

Fabrication and transport measurements of stacked double layer topological insulator devices  

NASA Astrophysics Data System (ADS)

A double-layer structure, consisting of two separated two-dimensional electron systems close in proximity, has been an interesting system to study novel ground states and transport properties driven by electron-electron interaction, e.g. Coulomb drag, exciton condensation, and counterflow superfluidity. Recently, topological insulators (TI), such as Bi2Se3 and Bi2Te3, have attracted much attention due to their exotic topologically protected spin-helical and Dirac-particle surface states. Motivated by a recently proposed ``topological exciton condensate'' that may be formed in two interacting TI surfaces, we have fabricated stacking double-layer TI structures and studied their electrical transport properties. Using a polyvinyl alcohol (PVA) based support film and micro-manipulator, double layer TI structures (Bi2Se3/boron nitride/Bi2Se3) were fabricated with exfoliated Bi2Se3 separated by thin boron nitride flakes (˜ 20 nm). We will present results from transport measurements including mutual-gated electrical field effect, Coulomb drag ,and counterflow conductivity.

Wu, Tai-Lung; Hu, Jiuning; Tian, Jifa; Mitkowski, Ireneusz; Chen, Yong P.

2013-03-01

353

Measuring rates of intraflagellar transport along Caenorhabditis elegans sensory cilia using fluorescence microscopy.  

PubMed

Intraflagellar transport (IFT), the kinesin-2 and IFT-dynein-dependent bidirectional movement of multisubunit protein complexes called IFT-particles and associated cargo molecules along ciliary axonemes, is thought to be essential for the assembly and maintenance of virtually all eukaryotic cilia and flagella. Transport assays that allow measurements of the rates of movement of specific, fluorescently tagged, functional components of the IFT machinery, including motors, IFT particle subunits, and putative cargo, were first developed in Caenorhabditis elegans sensory cilia, and they have proved to be an important and valuable tool for dissecting the molecular mechanisms of IFT. We describe how these transport assays are performed in our laboratory and summarize the information that has been obtained by using them concerning the mechanisms of action and regulation of the motors that drive IFT, the composition and organization of the IFT-particles, and the identification of IFT-dynein subunits and ciliary tubulin isotypes as likely cargo proteins of kinesin-2-driven anterograde IFT. PMID:23498746

Brust-Mascher, Ingrid; Ou, Guangshuo; Scholey, Jonathan M

2013-01-01

354

K? fluorescence measurement of relativistic electron transport in the context of fast ignition  

NASA Astrophysics Data System (ADS)

Electron transport within solid targets, irradiated by a high-intensity short-pulse laser, has been measured by imaging K? radiation from high- Z layers (Cu, Ti) buried in low- Z (CH, Al) foils. Although the laser spot is ˜10 ?m [full width at half maximum (FWHM)], the electron beam spreads to ?70 ?m FWHM within <20 ?m of penetration into an Al target then, at depths >100 ?m , diverges with a 40° spreading angle. Monte Carlo and analytic models are compared to our data. We find that a Monte Carlo model with a heuristic model for the electron injection gives a reasonable fit with our data.

Stephens, R. B.; Snavely, R. A.; Aglitskiy, Y.; Amiranoff, F.; Andersen, C.; Batani, D.; Baton, S. D.; Cowan, T.; Freeman, R. R.; Hall, T.; Hatchett, S. P.; Hill, J. M.; Key, M. H.; King, J. A.; Koch, J. A.; Koenig, M.; MacKinnon, A. J.; Lancaster, K. L.; Martinolli, E.; Norreys, P.; Perelli-Cippo, E.; Rabec Le Gloahec, M.; Rousseaux, C.; Santos, J. J.; Scianitti, F.

2004-06-01

355

Direct, Absolute, and In Situ Measurement of Fast Electron Transport via Cherenkov Emission  

SciTech Connect

We present direct measurements of the absolute energy distribution of relativistic electrons generated in intense, femtosecond laser interaction with a solid. Cherenkov emission radiated by these electrons in a novel prism target is spectrally dispersed to obtain yield and energy distribution of electrons simultaneously. A crucial advance is the observation of high density electron current as predicted by particle simulations and its transport as it happens inside the target. In addition, the strong sheath potential present at the rear side of the target is inferred from a comparison of the electron spectra derived from Cherenkov light observation with that from a magnet spectrometer.

Habara, Hideaki; Ohta, Kazuhide; Tanaka, Kazuo A.; Kumar, G. Ravindra; Krishnamurthy, M.; Kahaly, Subhendu; Mondal, Sudipta; Bhuyan, Manoj Kumar; Rajeev, R.; Zheng Jian [Graduate School of Engineering, Osaka University, 2-1 Suita, 565-0871, Osaka (Japan); Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai, 400-005 (India); Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026 (China)

2010-02-05

356

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...

357

Laboratory and field performance of a laser particle counter for measuring aeolian sand transport  

NASA Astrophysics Data System (ADS)

This paper reports the results of laboratory and field tests that evaluate the performance of a new laser particle counter for measuring aeolian sand transport. The Wenglor® model YH03PCT8 ("Wenglor") consists of a laser (655 nm), photo sensor, and switching circuit. When a particle passes through the 0.6 mm diameter, 30 mm long laser beam, the sensor outputs a digital signal. Laboratory tests with medium sand and a vertical gravity flume show that the Wenglor count rate scales approximately linearly with mass flux up to the saturation point of the sensor, after which the count rate decreases despite increasing mass flux. Saturation depends on the diameter and concentration of particles in the airstream and may occur during extreme events in the field. Below saturation sensor performance is relatively consistent; the mean difference between average count rate response was between 50 and 100 counts. Field tests provide a complimentary frame of reference for evaluating the performance of the Wenglor under varying environmental conditions and to gauge its performance with respect to a collocated piezoelectric impact sensor (Sensit H11-B). During 136.5 h of deployment on an active sand dune the relative proportion of time sand transport recorded by two Wenglors was 0.09% and 0.79%, compared to 4.68% by the Sensit H11-B. The weak performance of the Wenglors is attributed to persistent lens contamination from adhesion of sand grains on the sensors after rainfall. However, during dry and windy conditions the Wenglor performance improved substantially; sensors measured a concentration of sand particles in the airstream more than seven times greater than that measured by the Sensit. Between the two Wenglors, the mean absolute count rate difference was 6.16 counts per second, with a standard deviation of 8.53 counts per second. For short-term measurement campaigns in dry conditions, therefore, the Wenglor is relatively consistent and can outperform the Sensit in detecting particles in the airstream. The Sensit, however, is more reliable in detecting particle transport during longer unattended deployments. Two additional field tests show that the sensor is well-suited to the measurement of snow drifting but could be ineffective in dusty settings because of lens contamination. Overall, the main advantages of the Wenglor include (1) insensitivity to particle momentum; (2) low measurement variability; (3) low cost ($210 USD); and perhaps most important of all, (4) a consistent design that will improve comparison of results between investigations. At present, no other particle detector used in aeolian research can claim all these characteristics.

Hugenholtz, Chris H.; Barchyn, Thomas E.

2011-03-01

358

Monte Carlo simulation of time-dependent, transport-limited fluorescent boundary measurements in frequency domain.  

PubMed

Recently, we have presented and experimentally validated a unique numerical solver of the coupled radiative transfer equations (RTEs) for rapidly computing time-dependent excitation and fluorescent light propagation in small animal tomography. Herein, we present a time-dependent Monte Carlo algorithm to validate the forward RTE solver and investigate the impact of physical parameters upon transport-limited measurements in order to best direct the development of the RTE solver for optical tomography. Experimentally, the Monte Carlo simulations for both transport-limited and diffusion-limited propagations are validated using frequency domain photon migration measurements for 1.0%, 0.5%, and 0.2% intralipid solutions containing 1 microM indocyanine green in a 49 cm3 cylindrical phantom corresponding to the small volume employed in small animal tomography. The comparisons between Monte Carlo simulations and the numerical solutions result in mean percent error in amplitude and the phase shift less than 5.0% and 0.7 degrees, respectively, at excitation and emission wavelengths for varying anisotropic factors, lifetimes, and modulation frequencies. Monte Carlo simulations indicate that the accuracy of the forward model is enhanced using (i) suitable source models of photon delivery, (ii) accurate anisotropic factors, and (iii) accurate acceptance angles of collected photons. Monte Carlo simulations also show that the accuracy of the diffusion approximation in the small phantom depends upon (i) the ratio d(phantom)/l(tr), where d(phantom) is the phantom diameter and l(tr) is the transport mean free path; and (ii) the anisotropic factor of the medium. The Monte Carlo simulations validates and guides the future development of an appropriate RTE solver for deployment in small animal optical tomography. PMID:17500461

Pan, Tianshu; Rasmussen, John C; Lee, Jae Hoon; Sevick-Muraca, Eva M

2007-04-01

359

Measurement of the Critical Deposition Velocity in Slurry Transport through a Horizontal Pipe  

SciTech Connect

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.

Erian, Fadel F.; Furfari, Daniel J.; Kellogg, Michael I.; Park, Walter R.

2001-03-01

360

Measurements and modelling of molecular iodine emissions, transport and photodestruction in the coastal region around Roscoff  

NASA Astrophysics Data System (ADS)

Iodine emissions from the dominant six macroalgal species in the coastal regions around Roscoff, France, have been modelled to support the Reactive Halogens in the Marine Boundary Layer Experiment (RHaMBLe) undertaken in September 2006. A two-dimensional model is used to explore the relationship between geographically resolved regional emissions (based on maps of seaweed beds in the area and seaweed I2 emission rates previously measured in the laboratory) and in situ point and line measurements of I2 performed respectively by a broadband cavity ringdown spectroscopy (BBCRDS) instrument sited on the shoreline and a long-path differential optical absorption spectroscopy (LP-DOAS) instrument sampling over an extended light path to an off-shore island. The modelled point and line I2 concentrations compare quantitatively with BBCRDS and LP-DOAS measurements, and provide a link between emission fields and the different measurement geometries used to quantify atmospheric I2 concentrations during RHaMBLe. Total I2 emissions over the 100 km2 region around Roscoff are calculated to be 1.7×1019 molecules per second during the lowest tides. During the night, the model replicates I2 concentrations up to 50 pptv measured along the LP-DOAS instrument's line of sight, and predicts spikes of several hundred pptv in certain conditions. Point I2 concentrations up to 50 pptv are also calculated at the measurement site, in broad agreement with the BBCRDS observations. Daytime measured concentrations of I2 at the site correlate with modelled production and transport processes. However substantial recycling of the photodissociated I2 is required for the model to quantitatively match measured concentrations. This result corroborates previous modelling of iodine and NOx chemistry in the semi-polluted marine boundary layer which proposed a mechanism for recycling I2 via the formation, transport and subsequent reactions of the IONO2 reservoir compound. The methodology presented in this paper provides a tool for linking spatially distinct measurements to inhomogeneous and temporally varying emission fields.

Leigh, R. J.; Ball, S. M.; Whitehead, J.; Leblanc, C.; Shillings, A. J. L.; Mahajan, A. S.; Oetjen, H.; Lee, J. D.; Jones, C. E.; Dorsey, J. R.; Gallagher, M.; Jones, R. L.; Plane, J. M. C.; Potin, P.; McFiggans, G.

2010-12-01

361

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

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

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

2013-09-03

362

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

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.

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

2013-01-01

363

No Effect of Genome-Wide Copy Number Variation on Measures of Intelligence in a New Zealand Birth Cohort  

PubMed Central

Variation in human intelligence is approximately 50% heritable, but understanding of the genes involved is limited. Several forms of genetic variation remain under-studied in relation to intelligence, one of which is copy number variation (CNV). Using single-nucleotide polymorphism (SNP) -based microarrays, we genotyped CNVs genome-wide in a birth cohort of 723 New Zealanders, and correlated them with four intelligence-related phenotypes. We found no significant association for any common CNV after false discovery correction, which is consistent with previous work. In contrast to a previous study, however, we found no effect on any cognitive measure of rare CNV burden, defined as total number of bases inserted or deleted in CNVs rarer than 5%. We discuss possible reasons for this failure to replicate, including interaction between CNV and aging in determining the effects of rare CNVs. While our results suggest that no CNV assayable by SNP chips contributes more than a very small amount to variation in human intelligence, it remains possible that common CNVs in segmental duplication arrays, which are not well covered by SNP chips, are important contributors.

Bagshaw, Andrew T. M.; Horwood, L. John; Liu, Youfang; Fergusson, David M.; Sullivan, Patrick F.; Kennedy, Martin A.

2013-01-01

364

No effect of genome-wide copy number variation on measures of intelligence in a New Zealand birth cohort.  

PubMed

Variation in human intelligence is approximately 50% heritable, but understanding of the genes involved is limited. Several forms of genetic variation remain under-studied in relation to intelligence, one of which is copy number variation (CNV). Using single-nucleotide polymorphism (SNP) -based microarrays, we genotyped CNVs genome-wide in a birth cohort of 723 New Zealanders, and correlated them with four intelligence-related phenotypes. We found no significant association for any common CNV after false discovery correction, which is consistent with previous work. In contrast to a previous study, however, we found no effect on any cognitive measure of rare CNV burden, defined as total number of bases inserted or deleted in CNVs rarer than 5%. We discuss possible reasons for this failure to replicate, including interaction between CNV and aging in determining the effects of rare CNVs. While our results suggest that no CNV assayable by SNP chips contributes more than a very small amount to variation in human intelligence, it remains possible that common CNVs in segmental duplication arrays, which are not well covered by SNP chips, are important contributors. PMID:23383111

Bagshaw, Andrew T M; Horwood, L John; Liu, Youfang; Fergusson, David M; Sullivan, Patrick F; Kennedy, Martin A

2013-01-30

365

Measuring the Rest-Frame UV Properties and the Number Density of Massive Galaxies at 3  

NASA Astrophysics Data System (ADS)

One of the most controversial questions regarding the build-up of the stellar content of the universe is when and how the most massive galaxies formed. Recent studies have found that the number density of the most massive galaxies has evolved little from z=4 to z~1.5, contrary to the predictions from galaxy formation models, with the largest disagreement being at 3measure the number density of massive galaxies at 3

Marchesini, Danilo; Labbe, Ivo; Kriek, Mariska; van Dokkum, Pieter; Brammer, Gabriel; Muzzin, Adam; Bezanson, Rachel; Franx, Marijn; Illingworth, Garth; Lee, Kyoung-Soo; Quadri, Ryan; Rudnick, Greg; Whitaker, Katherine; Williams, Rik

2010-08-01

366

Measurements of air pollution emission factors for marine transportation in SECA  

NASA Astrophysics Data System (ADS)

The chemical composition of the plumes of seagoing ships was measured during a two week long measurement campaign in the port of Rotterdam, Hoek van Holland The Netherlands, in September 2009. Altogether, 497 ships were monitored and a statistical evaluation of emission factors (g kg-1 fuel) was provided. The concerned main atmospheric components were SO2, NO2, NOx and the aerosol particle number. In addition, the elemental and water-soluble ionic composition of the emitted particulate matter was determined. Emission factors were expressed as a function of ship type, power and crankshaft rotational speed. The average SO2 emission factor was found to be roughly half of what is allowed in sulphur emission control areas (16 vs. 30 g kg-1 fuel), and exceedances of this limit were rarely registered. A significant linear relationship was observed between the SO2 and particle number emission factors. The intercept of the regression line, 4.8 × 1015 (kg fuel)-1, gives the average number of particles formed during the burning of 1 kg zero sulphur content fuel, while the slope, 2 × 1018, provides the average number of particles formed with 1 kg sulphur burnt with the fuel. Water-soluble ionic composition analysis of the aerosol samples from the plumes showed that ~144 g of particulate sulphate was emitted from 1 kg sulphur burnt with the fuel. The mass median diameter of sulphate particles estimated from the measurements was ~42 nm.

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

2013-07-01

367

The ESO transportable LGS Unit for measurements of the LGS photon return and other experiments  

NASA Astrophysics Data System (ADS)

Sodium laser guide stars (LGS) are used, or planned to be used, as single or multiple artificial beacons for Adaptive Optics in many present or future large and extremely large telescopes projects. In our opinion, several aspects of the LGS have not been studied systematically and thoroughly enough in the past to ensure optimal system designs. ESO has designed and built, with support from industry, an experimental transportable laser guide star unit, composed of a compact laser based on the ESO narrow-band Raman Fiber Amplifier patented technology, attached to a 30cm launch telescope. Besides field tests of the new laser technology, the purpose of the transportable unit is to conduct field experiments related to LGS and LGS-AO, useful for the optimization of future LGS-AO systems. Among the proposed ones are the validation of ESO LGS return flux simulations as a function of CW and pulsed laser properties, the feasibility of line-of-sight sodium profile measurements via partial CW laser modulation and tests of AO operation with elongated LGS in the EELT geometry configuration. After a description of the WLGSU and its main capabilities, results on the WLGSU commissioning and LGS return flux measurements are presented.

Bonaccini Calia, D.; Guidolin, I.; Friedenauer, A.; Hager, M.; Karpov, V.; Pfrommer, T.; Holzlöhner, R.; Lewis, S.; Hackenberg, W.; Lombardi, G.; Centrone, M.; Pedichini, F.

2012-09-01

368

Probing the edge of a 2DEG by time-resolved transport measurements  

NASA Astrophysics Data System (ADS)

We have studied time-resolved transport in a two-dimensional electron gas in the integer and fractional quantum Hall regime. In samples with a smooth edge and an additional screening electrode, the propagation velocity of high-frequency signals depends on the number and width of the involved edge channels, and thus can be used to obtain an approximate electron density profile. The amplitude of the transmitted signals oscillates with respect to the applied magnetic field with maxima appearing close to integer and fractional bulk filling factors. While the data around filling factor 1/3 are qualitatively similar to those around filling factors 1 and 2, deviations appear around filling factor 2/3. At odd filling factors, signal propagation in partially decoupled edge channels is observed.

Ernst, G.; Zhitenev, N. B.; Haug, R. J.; von Klitzing, K.

1998-01-01

369

Comparison of nickel silicide and aluminium ohmic contact metallizations for low-temperature quantum transport measurements  

PubMed Central

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.

2011-01-01

370

Comparison of nickel silicide and aluminium ohmic contact metallizations for low-temperature quantum transport measurements.  

PubMed

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

Polley, Craig M; Clarke, Warrick R; Simmons, Michelle Y

2011-10-03

371

Aerosol Measurements From Recent Alaskan Volcanic Eruptions: Implications for Volcanic Ash Transport Predictions  

NASA Astrophysics Data System (ADS)

Size and time-resolved aerosol compositional measurements conducted during the 2006 Augustine Volcano and 2007 Pavlof Volcano eruptions provide ground-truth information for use in the validation of volcanic ash transport models. These measurements provide quantitative information on the size and concentration of the aerosol, which can be used to test the volcanic aerosol source profiles and transport characteristics used in volcanic ash transport models. Augustine Volcano is on an island in Cook Inlet in southern Alaska. For the 2006 Augustine Volcano eruption, the size and time-resolved aerosol measurements were made using an eight stage (35-5.0, 5.0-2.5, 2.5-1.15, 1.15- 0.75, 0.75-0.56, 0.56-0.34, 0.34-0.26 and 0.26-0.09 microns in aerodynamic diameter) DRUM aerosol impactor deployed in Homer, approximately 120 km northeast of the volcano. Aerosols from the volcano reached the sampler and showed that the size distribution of the volcanic emissions changed during the course of the eruption. For example, crustal elements were present in high concentrations in the largest size fraction (35-5.0 microns) but low concentrations in a smaller size fraction (0.75-0.56 microns) during the phreatomagmatic explosive events. However, during the magmatic emissions period, the concentrations of these elements in the large size fraction decreased, but greatly increased in the smaller size fraction. Pavlof Volcano is a volcano on the Alaska Peninsula in southwestern Alaska. During the 2007 Pavlof Volcano eruption, a network of four DRUM aerosol impactors was deployed downwind of the volcano in an attempt to characterize the change in aerosol size distribution and composition during transport away from the volcano. The samplers were located at Nelson Lagoon, approximately 80 km northeast of the volcano (eight stage DRUM impactor with a top cut point of approximately 12 microns), Sand Point approximately 90 km east of the volcano (three stage DRUM impactor with aerodynamic diameter size fractions of 2.5-1.15, 1.15-0.34 and 0.34-0.01 microns), Kodiak, approximately 550 km east-northeast of the volcano (three stage DRUM impactor), and Homer, approximately 680 km northeast (three stage DRUM impactor). The aerosol samples collected by the DRUM impactors were analyzed with 90 minute resolution for the entire duration of the six-week sample periods. The collected aerosol was analyzed for mass using a beta-gauge and elemental composition (28 selected elements between sodium and lead) using synchrotron x-ray fluorescence. The results from Pavlof Volcano will be compared to those of Augustine Volcano to determine the variability of aerosol emissions between the two eruptions. The Pavlof Volcano aerosol network will also be used to examine changes in size distribution and composition as the aerosols transport away from the volcano. The information gained from these analyses will be compared to volcanic ash transport model predictions to help quantify the limitations of the models and improve future volcanic ash predictions.

Cahill, C. F.; Rinkleff, P. G.; Dehn, J.; Webley, P.; Cahill, T. A.; Barnes, D. E.

2007-12-01

372

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

SciTech Connect

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.

Eastman, J.A.

1983-01-01

373

Eddy Correlation Measurements of the Resistance to Vertical Transport of Ozone.  

NASA Astrophysics Data System (ADS)

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 F was determined by computing the covariance between the vertical wind speed w and the ozone concentration c using both analog and digital methods, by means of. F = -c'w',. where the overbar represents a temporal average and the prime indicates deviation from the average value of the respective quantities. 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. Data were adjusted to compensate for the inadequate response of the sensors to high frequency fluctuations, delay times caused by physical separation of the sensors and ozone transit through its sampling tube, and air density effects. The total resistance to vertical transport of ozone was computed for sampling periods up to one half -hour long by dividing the average ozone concentration by the vertical flux. 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, indicated ozone destruction by non-transpiring 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.

Eastman, John August

374

Ultrasound field estimation method using a secondary source-array numerically constructed from a limited number of pressure measurements  

PubMed

A new and faster method for the accurate estimation of acoustic fields of underwater ultrasonic transducers was developed, tested experimentally, and compared to previously reported methods. Using a limited number of pressure measurements close to the transducer's face, the method numerically constructs a virtual secondary source-array whose acoustic field is similar to the field generated by the actual transducer (primary source). The measured data are used to obtain the normal particle velocity on the surface of the virtual secondary source-array, which in turn permits the calculation of the forward propagating field using the Rayleigh-Sommerfeld diffraction integral. The method is novel in that it constructs a virtual secondary source-array, thus eliminating the problems associated with obtaining the excitation source of a real transducer; and it is faster because it uses finite differences instead of a matrix inversion to obtain the excitation source. Results showed that predicted ultrasound fields agreed quantitatively and qualitatively with measured fields for three commonly used transducer types: two planar radiators (one circular, 0.5 MHz, 1.9-cm diam.; and one square, 1 MHz, 1.2 cm on a side), and a sharply focused radiator (1.5 MHz, 10-cm diam., 10-cm radius of curvature). The agreements suggest that the secondary source-array method (SSAM) is applicable to a wide range of radiator sizes, shapes, and operating frequencies. The SSAM was also compared to these authors' previous equivalent phased array methods (EPAM) [J. Acoust. Soc. Am. 102, 2734-2741 (1997); and Concentric ring equivalent phased array method (CREPAM), UFFC 46, 830-841 (1999)] which require matrix inversions. The SSAM proved to be much faster and equally or more nearly accurate than the previous methods. PMID:10875371

Fan; Moros; Straube

2000-06-01

375

Mesoscale Backtracking by Means of Atmospheric Transport Modeling of Xenon Plumes Measured by Radionuclide Gas Stations  

NASA Astrophysics Data System (ADS)

The monitoring of atmospheric radioactive xenon concentration is performed for nuclear safety regulatory requirements. It is also planned to be used for the detection of hypothetical nuclear tests in the framework of the Comprehensive nuclear-Test-Ban Treaty (CTBT). In this context, the French Atomic Energy Commission designed a high sensitive and automated fieldable station, named SPALAX, to measure the activity concentrations of xenon isotopes in the atmosphere. SPALAX stations were set up in Western Europe and have been operated quite continuously for three years or more, detecting principally xenon-133 and more scarcely xenon-135, xenon-133m and xenon-131m. There are around 150 nuclear power plants in the European Union, research reactors, reprocessing plants, medical production and application facilities releasing radioactive xenon in normal or incidental operations. A numerical study was carried out aiming to explain the SPALAX measurements. The mesoscale Atmospheric Transport Modelling involves the MM5 suite (PSU- NCAR) to predict the wind fields on nested domains, and FLEXPART, a 3D Lagrangian particle dispersion code, used to simulate the backward transport of xenon plumes detected by the SPALAX. For every event of detection, at least one potential xenon source has a significant efficiency of emission. The identified likely sources are located quite close to the SPALAX stations (some tens of kilometres), or situated farther (a few hundreds of kilometres). A base line of some mBq per cubic meter in xenon-133 is generated by the nuclear power plants. Peaks of xenon-133 ranging from tens to hundreds of mBq per cubic meter originate from a radioisotope production facility. The calculated xenon source terms required to obtain the SPALAX measurements are discussed and seem consistent with realistic emissions from the xenon sources in Western Europe.

Armand, P. P.; Achim, P.; Taffary, T.

2006-12-01

376

Improving measurements of SF6 for the study of atmospheric transport and emissions  

NASA Astrophysics Data System (ADS)

Sulfur hexafluoride (SF6) is a potent greenhouse gas and useful atmospheric tracer. Measurements of SF6 on global and regional scales are necessary to estimate emissions and to verify or examine the performance of atmospheric transport models. Typical precision for common gas chromatographic methods with electron capture detection (GC-ECD) is 1-2 %. A method for improving measurement precision is described. We have modified a common GC-ECD method to achieve measurement precision of 0.5 % or better. Global mean SF6 measurements were used to examine changes in the growth rate of SF6 and corresponding SF6 emissions. Global emissions and mixing ratios from 2000-2008 are consistent with recently published work. More recent observations show a 10 % decline in SF6 emissions in 2008-2009, which seems to coincide with a decrease in world economic output. This decline was short-lived, as the global SF6 growth rate has recently increased to near its 2007-2008 maximum value of 0.30 ± 0.03 pmol mol-1 (ppt) yr-1 (95 % C.L.).

Hall, B. D.; Dutton, G. S.; Mondeel, D. J.; Nance, J. D.; Rigby, M.; Butler, J. H.; Moore, F. L.; Hurst, D. F.; Elkins, J. W.

2011-07-01

377

Association between Proton Magnetic Resonance Spectroscopy Measurements and CAG Repeat Number in Patients with Spinocerebellar Ataxias 2, 3, or 6  

PubMed Central

The aim of this study was to correlate magnetic resonance spectroscopy (MRS) measurements, including that for the N-acetyl aspartate (NAA)/creatine (Cr) ratio in the vermis (denoted V-NAA), right cerebellar hemisphere (R-NAA), and left (L-NAA) cerebellar hemisphere, with the clinical scale for the assessment and rating of ataxia (SARA) score for patients with spinocerebellar ataxia (SCA) types 2, 3, and 6. A total of 24 patients with SCA2, 48 with SCA3, and 16 with SCA6 were recruited; 12 patients with SCA2, 43 with SCA3, and 8 with SCA6 underwent detailed magnetic resonance neuroimaging. Forty-four healthy, age-matched individuals without history of neurologic disease served as control subjects. V-NAA and patient age were used to calculate the predicted age at which a patient with SCA2 or SCA3 would reach an onset V-NAA value. Results showed the following: the NAA/Cr ratio decreased with increasing age in patients with SCA but not in control subjects; the SARA score increased progressively with age and duration of illness; V-NAA showed a better correlation with SARA score than R-NAA in patients with SCA2 or SCA3; the ratio of age to V-NAA correlated well with CAG repeat number; the retrospectively predicted age of onset for SCA2 and SCA3 was consistent with patient-reported age of onset; R-NAA showed a better correlation with SARA score than V-NAA in patients with SCA6; V-NAA and R-NAA correlated with clinical severity (SARA score) in patients with SCA. The correlation between CAG repeat number and age could be expressed as a simple linear function, which might explain previous observations claiming that the greater the CAG repeat number, the earlier the onset of illness and the faster the disease progression. These findings support the use of MRS values to predict age of disease onset and to retrospectively evaluate the actual age of disease onset in SCA.

Wang, Po-Shan; Chen, Hung-Chieh; Wu, Hsiu-Mei; Lirng, Jiing-Feng; Wu, Yu-Te; Soong, Bing-Wen

2012-01-01

378

Direct measurement of calcium transport across chloroplast inner-envelope vesicles  

SciTech Connect

The initial rate of Ca{sup 2+} movement across the inner-envelope membrane of pea (Pisum sativum L.) chloroplasts was directly measured by stopped-flow spectrofluorometry using membrane vesicles loaded with the Ca{sup 2+}-sensitive fluorophore fura-2. Calibration of fura-2 fluorescence was achieved by combining a ratiometric method with Ca{sup 2+}-selective minielectrodes to determine pCa values. The initial rate of Ca{sup 2+} influx in predominantly right-side-out inner-envelope membrane vesicles was greater than that in largely inside-out vesicles. Ca{sup 2+} movement was stimulated by an inwardly directed electrochemical proton gradient across the membrane vesicles, an effect that was diminished by the addition of valinomycin in the presence of K{sup +}. In addition, Ca{sup 2+} was shown to move across the membrane vesicles in the presence of K{sup +} diffusion potential gradient. The potential-stimulated rate of Ca{sup 2+} transport was slightly inhibited by diltiazem and greatly inhibited by ruthenium red. Other pharmacological agents such as LaCl{sub 3}, verapamil, and nifedipine had little or no effect. These results indicate that Ca{sup 2+} transport across the chloroplast inner envelope can occur by a potential-stimulated uniport mechanism.

Roh, M.H.; Shingles, R.; Cleveland, M.J.; McCarty, R.E. [Johns Hopkins Univ., Baltimore, MD (United States). Dept. of Biology

1998-12-01

379

TCP fiber: direct measurement optical transport congestion control for beyond 10 gigabit networks  

NASA Astrophysics Data System (ADS)

Optical or gigabit communication links could currently allow petabytes of data to be transferred to geographically distributed tera-scale computing facilities at beyond 10Gbps rates. While the bandwidth is available in network link technology, transport protocols like TCP/IP and common network host architectures severely limit the attainable throughput over such links. Traditional layering -that is implemented through excessive per-byte (word) memory bandwidth constrained buffer copying- transport processing complexity, combined error and congestion control and trial and error timeout-based approaches result in prohibitively increasing performance degradation as network speeds increase. In this paper we present TCP-Fiber, a TCP version that is based on direct measurements of available and bottleneck link bandwidth and is able to perform decoupled error and congestion control while supporting zero-copy from application to network interface. A key innovation in TCP-Fiber is a variable length "packet train" based method that allows sensing ultra high bandwidth related quantities in a network independent fashion with relaxed requirements to timers and system resources (as related to interrupts, system calls etc). A TCP-Fiber connection is able to fairly send at the full network rate without extensive trial-and-error convergence procedures or waiting on time-out for unacknowledged packets, while maintaining network stability.

Kazantzidis, Matheos

2006-06-01

380

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

SciTech Connect

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.

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

2009-03-02

381

Combining in-situ measurements and altimetry to estimate volume, heat and salt transport variability through the Faroe Shetland Channel  

NASA Astrophysics Data System (ADS)

From 1994 to 2011, instruments measuring ocean currents (ADCPs) have been moored on a section crossing the Faroe-Shetland Channel. Together with CTD (Conductivity Temperature Depth) measurements from regular research vessel occupations, they describe the flow field and water mass structure in the channel. Here, we use these data to calculate the average volume transport and properties of the flow of warm water through the channel from the Atlantic towards the Arctic, termed the Atlantic inflow. We find the average volume transport of this flow to be 2.7 ± 0.5 Sv (1 Sv = 106 m3 s-1) between the shelf edge on the Faroe side and the 150 m isobath on the Shetland side. The average heat transport (relative to 0 °C) was estimated to be 107 ± 21 TW and the average salt import to be 98 ± 20 × 106 kg s-1. Transport values for individual months, based on the ADCP data, include a large level of variability, but can be used to calibrate sea level height data from satellite altimetry. In this way, a time series of volume transport has been generated back to the beginning of satellite altimetry in December 1992. The Atlantic inflow has a seasonal variation in volume transport that peaks around the turn of the year and has an amplitude of 0.7 Sv. The Atlantic inflow has become warmer and more saline since 1994, but no equivalent trend in volume transport was observed.

Berx, B.; Hansen, B.; Østerhus, S.; Larsen, K. M.; Sherwin, T.; Jochumsen, K.

2013-01-01

382

Measurement of anisotropic energy transport in flowing polymers by using a holographic technique.  

PubMed

Almost no experimental data exist to test theories for the nonisothermal flow of complex fluids. To provide quantitative tests for newly proposed theories, we have developed a holographic grating technique to study energy transport in an amorphous polymer melt subject to flow. Polyisobutylene with weight-averaged molecular mass of 85 kDa is sheared at a rate of 10 s(-1), and all nonzero components of the thermal conductivity tensor are measured as a function of time, after cessation. Our results are consistent with proposed generalizations to the energy balance for microstructural fluids, including a generalized Fourier's law for anisotropic media. The data are also consistent with a proposed stress-thermal rule for amorphous polymer melts. Confirmation of the universality of these results would allow numerical modelers to make quantitative predictions for the nonisothermal flow of polymer melts. PMID:15340152

Schieber, Jay D; Venerus, David C; Bush, Kendall; Balasubramanian, Venkat; Smoukov, Stoyan

2004-08-30

383

One-dimensional Brownian-motion model for transport measurements in high-temperature superconductors  

SciTech Connect

Using a one-dimensional model of Brownian motion of vortices over pinning wells, we derive a current-voltage equation assuming a distribution of the effective pinning length. The model describes linear and nonlinear regimes of the {ital E}({ital J}) curves in a single-particle description. Thermally activated flux flow and flux flow define the two limits of the dissipative process, respectively, at very low and high current. The pinning relief is described by pinning well depth and pinning well gradient, respectively, which can be checked by resistive and current-voltage measurements. The model is then applied to a YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} thin film. It provides a phenomenological model of the dissipation induced by transport current. {copyright} {ital 1996 The American Physical Society.}

Goupil, C.; Aouaroun, T.; Thopart, D.; Hamet, J.F.; Simon, C. [CRISMAT ISMRA Centre National de la Recherche Scientifique, 6 Bd Mal Juin, 14050 Caen (France)

1996-12-01

384

Surface doping in T6/PDI-8CN2 heterostructures investigated by transport and photoemission measurements  

NASA Astrophysics Data System (ADS)

In this paper, we discuss the surface doping in sexithiophene (T6) organic field-effect transistors by N,N'-bis (n-octyl)-dicyanoperylenediimide (PDI-8CN2). We show that an accumulation heterojunction is formed at the interface between the organic semiconductors and that the consequent band bending in T6 caused by PDI-8CN2 deposition can be addressed as the cause of the surface doping in T6 transistors. Several evidences of this phenomenon have been furnished both by electrical transport and photoemission measurements, namely, the increase in the conductivity, the shift of the threshold voltage, and the shift of the T6 highest occupied molecular orbital peak towards higher binding energies.

Aversa, L.; Verucchi, R.; Tatti, R.; Di Girolamo, F. V.; Barra, M.; Ciccullo, F.; Cassinese, A.; Iannotta, S.

2012-12-01

385

Volume Transports from moored geostrophic and direct Measurements in the Deep Western Boundary Current east of Abaco, Bahamas  

Microsoft Academic Search

Moored geostrophic measurements are receiving increased attention in oceanic monitoring applications as they yield a horizontally integrated measure of the volume transport. Thus, they provide an inexpensive tool for climate research. Examples of ongoing or planned applications of this technique include the German MOVE experiment in the tropical Atlantic (operating since 2000) and a joint UK\\/US program designed to monitor

T. Kanzow; W. E. Johns; R. Zantopp

2003-01-01

386

The impact of transportation control measures on emission reductions during the 2008 Olympic Games in Beijing, China  

Microsoft Academic Search

Traffic congestion and air pollution were two major challenges for the planners of the 2008 Olympic Games in Beijing. The Beijing municipal government implemented a package of temporary transportation control measures during the event. In this paper, we report the results of a recent research project that investigated the effects of these measures on urban motor vehicle emissions in Beijing.

Yu Zhou; Ye Wu; Liu Yang; Lixin Fu; Kebin He; Shuxiao Wang; Jiming Hao; Jinchuan Chen; Chunyan Li

2010-01-01

387

Twin sample chamber for simultaneous comparative transport measurements in a diamond anvil cell.  

PubMed

In static high pressure experiments, performed within a diamond anvil cell (DAC), several different methods of thermometry may be employed to determine the temperature of the sample. Due to different DAC designs or particular experimental designs or goals, uncertainties in the determination of the temperature of a given sample exist. To overcome the inaccuracy in comparing the temperature dependence of transport properties of different materials at high pressure, we have used a novel design of resistivity measurement in a twin sample chamber built on an insulated gasket in a DAC. In this design, the transport properties of two samples will be measured simultaneously and therefore the two samples will always be in the same relative temperatures. The uncertainties in the temperatures of the two samples will be exactly the same and therefore their relative phase diagram will be compared precisely. The pressures of the chambers can be slightly different and is easily determined by the ruby pieces placed in each chamber. To demonstrate the feasibility of this method we have compared the superconducting properties of two YBa2Cu3O7-x (0 ? x ? 0.65) samples with slightly different superconducting transition temperatures at ambient pressure as a function of pressures up to 11 GPa. The upper limit of the pressure achieved using this design would be lower than single chamber gaskets. The highest achievable pressure, as in a conventional single hole setup, depends upon the thickness of the gasket, the culet size, the size, and symmetry of the sample chamber. For the twin chamber, it also depends upon the separation of the holes from each other as well as from the edge of the culet. PMID:24089867

Schaeffer, Anne Marie J; Deemyad, Shanti

2013-09-01

388

Twin sample chamber for simultaneous comparative transport measurements in a diamond anvil cell  

NASA Astrophysics Data System (ADS)

In static high pressure experiments, performed within a diamond anvil cell (DAC), several different methods of thermometry may be employed to determine the temperature of the sample. Due to different DAC designs or particular experimental designs or goals, uncertainties in the determination of the temperature of a given sample exist. To overcome the inaccuracy in comparing the temperature dependence of transport properties of different materials at high pressure, we have used a novel design of resistivity measurement in a twin sample chamber built on an insulated gasket in a DAC. In this design, the transport properties of two samples will be measured simultaneously and therefore the two samples will always be in the same relative temperatures. The uncertainties in the temperatures of the two samples will be exactly the same and therefore their relative phase diagram will be compared precisely. The pressures of the chambers can be slightly different and is easily determined by the ruby pieces placed in each chamber. To demonstrate the feasibility of this method we have compared the superconducting properties of two YBa2Cu3O7-x (0 <= x <= 0.65) samples with slightly different superconducting transition temperatures at ambient pressure as a function of pressures up to 11 GPa. The upper limit of the pressure achieved using this design would be lower than single chamber gaskets. The highest achievable pressure, as in a conventional single hole setup, depends upon the thickness of the gasket, the culet size, the size, and symmetry of the sample chamber. For the twin chamber, it also depends upon the separation of the holes from each other as well as from the edge of the culet.

Schaeffer, Anne Marie J.; Deemyad, Shanti

2013-09-01

389

Thermal transport across incommensurate phases in potassium selenate: photo-pyroelectric and calorimetric measurements.  

PubMed

The thermal transport properties-thermal diffusivity, thermal conductivity and specific heat capacity-of potassium selenate crystal have been measured through the successive phase transitions, following the photo-pyroelectric thermal wave technique. The variation of thermal conductivity with temperature through the incommensurate (IC) phase of this crystal is measured. The enhancement in thermal conductivity in the IC phase is explained in terms of heat conduction by phase modes, and the maxima in thermal conductivity during transitions is due to enhancement in the phonon mean free path and the corresponding reduction in phonon scattering. The anisotropy in thermal conductivity and its variation with temperature are reported. The variation of the specific heat with temperature through the high temperature structural transition at 745 K is measured, following the differential scanning calorimetric method. By combining the results of photo-pyroelectric thermal wave methods and differential scanning calorimetry, the variation of the specific heat capacity with temperature through all the four phases of K(2)SeO(4) is reported. The results are discussed in terms of phonon mode softening during transitions and phonon scattering by phase modes in the IC phase. PMID:21715826

Philip, J; Manjusha, M V

2008-12-15

390

Photosynthetic electron transport in an anoxygenic photosynthetic bacterium Afifella (Rhodopseudomonas) marina measured using PAM fluorometry.  

PubMed

Blue diode-based pulse amplitude modulation (PAM) technology can be used to measure the photosynthetic electron transport rate (ETR) in a purple nonsulfur anoxygenic photobacterium, Afifella (Rhodopseudomonas) marina. Rhodopseudomonads have a reaction center light harvesting antenna complex containing an RC-2 type bacteriochlorophyll a protein (BChl a RC-2-LH1) which has a blue absorption peak and variable fluorescence similar to PSII. Absorptance of cells filtered onto glass fiber disks was measured using a blue-diode-based absorptance meter (Blue-RAT) so that absolute ETR could be calculated from PAM experiments. Maximum quantum yield (Y) was ?0.6, decreasing exponentially as irradiance increased. ETR vs irradiance (P vs E) curves fitted the waiting-in-line model (ETR = (ETRmax  × E/Eopt ) × exp(1 - E/Eopt )). Maximum ETR (ETRmax ) was ?1000-2000 ?mol e(-)  mg(-1)  BChl a h(-1) . Fe(2+) , bisulfite and thiosulfate act as photosynthetic electron donors. Optimum irradiance was ?100 ?mol m(-2)  s(-1) PPFD even in Afifella grown in sunlight. Quantum efficiencies (?) were ?0.3-0.4 mol e(-)  mol h?(-1) ; or ?11.8 ± 2.9 mol e(-)  mol h?(-1)  m(2)  ?g(-1)  BChl a). An underlying layer of Afifella in a constructed algal/photosynthetic bacterial mat has little effect on the measured ETR of the overlying oxyphotoautotroph (Chlorella). PMID:22978665

Ritchie, Raymond J; Runcie, John W

391

Improving measurements of SF6 for the study of atmospheric transport and emissions  

NASA Astrophysics Data System (ADS)

Sulfur hexafluoride (SF6) is a potent greenhouse gas and useful atmospheric tracer. Measurements of SF6 on global and regional scales are necessary to estimate emissions and to verify or examine the performance of atmospheric transport models. Typical precision for common gas chromatographic methods with electron capture detection (GC-ECD) is 1-2%. We have modified a common GC-ECD method to achieve measurement precision of 0.5% or better. Global mean SF6 measurements were used to examine changes in the growth rate of SF6 and corresponding SF6 emissions. Global emissions and mixing ratios from 2000-2008 are consistent with recently published work. More recent observations show a 10% decline in SF6 emissions in 2008-2009, which seems to coincide with a decrease in world economic output. This decline was short-lived, as the global SF6 growth rate has recently increased to near its 2007-2008 maximum value of 0.30±0.03 pmol mol-1 (ppt) yr-1 (95% C.L.).

Hall, B. D.; Dutton, G. S.; Mondeel, D. J.; Nance, J. D.; Rigby, M.; Butler, J. H.; Moore, F. L.; Hurst, D. F.; Elkins, J. W.

2011-11-01

392

Measurement of Fracture Aperture Fields Using Ttransmitted Light: An Evaluation of Measurement Errors and their Influence on Simulations of Flow and Transport through a Single Fracture  

SciTech Connect

Understanding of single and multi-phase flow and transport in fractures can be greatly enhanced through experimentation in transparent systems (analogs or replicas) where light transmission techniques yield quantitative measurements of aperture, solute concentration, and phase saturation fields. Here we quanti@ aperture field measurement error and demonstrate the influence of this error on the results of flow and transport simulations (hypothesized experimental results) through saturated and partially saturated fractures. find that precision and accuracy can be balanced to greatly improve the technique and We present a measurement protocol to obtain a minimum error field. Simulation results show an increased sensitivity to error as we move from flow to transport and from saturated to partially saturated conditions. Significant sensitivity under partially saturated conditions results in differences in channeling and multiple-peaked breakthrough curves. These results emphasize the critical importance of defining and minimizing error for studies of flow and transpoti in single fractures.

Detwiler, Russell L.; Glass, Robert J.; Pringle, Scott E.

1999-05-06

393

Continuous non-contact measurement of electric charges of solid particles in pipes of pneumatic transport. II. Measuring system and its application  

Microsoft Academic Search

For pt.I see ibid., vol.2, p.1958-63, 1989. A measuring system that enables the electric charges of solid particles in a pneumatic-transport pipe to be conveniently, precisely, reliably, and quickly measured is described. The system is made up of a measuring head comprising a sensing element (metal inductive ring probe), a parallel-to-input capacitor of a high capacitance value, and a preamplifier;

Juliusz B. Gajewski; B. Glod; Ryszard A. Grobelny; W. Kala

1989-01-01

394

Integration of field measurements and reactive transport modelling to evaluate contaminant transport at a sulfide mine tailings impoundment  

NASA Astrophysics Data System (ADS)

Over a decade of field observations including geochemical, mineralogical and hydrological information are available on the generation of acid mine drainage from the Pistol Dam region of the P-area of Inco's tailings impoundment in Copper Cliff, Ontario. This work focuses on the integration and quantitative assessment of this data set using reactive transport modeling. The results of the reactive transport simulations are in general agreement with the field observations; however, exact agreement between the field and simulated results was not the objective of this study, and was not attained. Many factors contribute to the discrepancies between the field observations and simulation results including geochemical and hydrogeological complexities and necessary model simplifications. For example, fluctuating water levels observed at the site were averaged and described using a steady state flow system. In addition, the lack of representative thermodynamic and rate expression data contributed to the discrepancies between observations and simulation results, thus further research into the applicability of laboratory-derived thermodynamic and rate expression data to field conditions could minimize these discrepancies. Despite the discrepancies between the field observations and simulated results, integrating field observations with numerical modelling of the P-area tailings impoundment allowed for a more complete understanding of what affects the complex geochemical reactions.

Brookfield, A. E.; Blowes, D. W.; Mayer, K. U.

2006-11-01

395

Inhalable particulate matter and mitochondrial DNA copy number in highly exposed individuals in Beijing, China: a repeated-measure study  

PubMed Central

Background Mitochondria are both a sensitive target and a primary source of oxidative stress, a key pathway of air particulate matter (PM)-associated diseases. Mitochondrial DNA copy number (MtDNAcn) is a marker of mitochondrial damage and malfunctioning. We evaluated whether ambient PM exposure affects MtDNAcn in a highly-exposed population in Beijing, China. Methods The Beijing Truck Driver Air Pollution Study was conducted shortly before the 2008 Beijing Olympic Games (June 15-July 27, 2008) and included 60 truck drivers and 60 office workers. Personal PM2.5 and elemental carbon (EC, a tracer of traffic particles) were measured during work hours using portable monitors. Post-work blood samples were obtained on two different days. Ambient PM10 was averaged from 27 monitoring stations in Beijing. Blood MtDNAcn was determined by real-time PCR and examined in association with particle levels using mixed-effect models. Results In all participants combined, MtDNAcn was negatively associated with personal EC level measured during work hours (?=?0.059, 95% CI: -0.011; -0.0006, p=0.03); and 5-day (?=?0.017, 95% CI: -0.029;-0.005, p=0.01) and 8-day average ambient PM10 (?=?0.008, 95% CI: -0.043; -0.008, p=0.004) after adjusting for possible confounding factors, including study groups. MtDNAcn was also negatively associated among office workers with EC (?=?0.012, 95% CI: -0.022;-0.002, p=0.02) and 8-day average ambient PM10 (?=?0.030, 95% CI: -0.051;-0.008, p=0.007). Conclusions We observed decreased blood MtDNAcn in association with increased exposure to EC during work hours and recent ambient PM10 exposure. Our results suggest that MtDNAcn may be influenced by particle exposures. Further studies are required to determine the roles of MtDNAcn in the etiology of particle-related diseases.

2013-01-01

396

Apparatus and method for detecting and measuring changes in linear relationships between a number of high frequency signals  

DOEpatents

An electronic measurement circuit is disclosed for high speed comparison of the relative amplitudes of a predetermined number of electrical input signals independent of variations in the magnitude of the sum of the signals. The circuit includes a high speed electronic switch that is operably connected to receive on its respective input terminals one of said electrical input signals and to have its common terminal serve as an input for a variable-gain amplifier-detector circuit that is operably connected to feed its output to a common terminal of a second high speed electronic switch. The respective terminals of the second high speed electronic switch are operably connected to a plurality of integrating sample and hold circuits, which in turn have their outputs connected to a summing logic circuit that is operable to develop first, second and third output voltages, the first output voltage being proportional to a predetermined ratio of sums and differences between the compared input signals, the second output voltage being proportional to a second summed ratio of predetermined sums and differences between said input signals, and the third output voltage being proportional to the sum of signals to the summing logic circuit. A servo system that is operably connected to receive said third output signal and compare it with a reference voltage to develop a slowly varying feedback voltage to control the variable-gain amplifier in said common amplifier-detector circuit in order to make said first and second output signals independent of variations in the magnitude of the sum of said input signals. 2 figures.

Bittner, J.W.; Biscardi, R.W.

1991-03-19

397

Apparatus and method for detecting and measuring changes in linear relationships between a number of high frequency signals  

DOEpatents

An electronic measurement circuit for high speed comparison of the relative amplitudes of a predetermined number of electrical input signals independent of variations in the magnitude of the sum of the signals. The circuit includes a high speed electronic switch that is operably connected to receive on its respective input terminals one of said electrical input signals and to have its common terminal serve as an input for a variable-gain amplifier-detector circuit that is operably connected to feed its output to a common terminal of a second high speed electronic switch. The respective terminals of the second high speed electronic switch are operably connected to a plurality of integrating sample and hold circuits, which in turn have their outputs connected to a summing logic circuit that is operable to develop first, second and third output voltages, the first output voltage being proportional to a predetermined ratio of sums and differences between the compared input signals, the second output voltage being proportional to a second summed ratio of predetermined sums and differences between said input signals, and the third output voltage being proportional to the sum of signals to the summing logic circuit. A servo system that is operably connected to receive said third output signal and compare it with a reference voltage to develop a slowly varying feedback voltage to control the variable-gain amplifier in said common amplifier-detector circuit in order to make said first and second output signals independent of variations in the magnitude of the sum of said input signals.

Bittner, John W. (Shoreham, NY); Biscardi, Richard W. (Ridge, NY)

1991-01-01

398

Measurements of dynamo electric field and momentum transport induced by fluctuations on HIST  

NASA Astrophysics Data System (ADS)

Coaxial Helicity injection (CHI) is an efficient current-drive method used in spheromak and spherical torus (ST) experiments. It is an important issue to investigate dynamo effect to explore CHI current drive mechanisms. To establish the dynamo model with two-fluid Hall effects, we verify the parallel mean-field Ohm's law balance. The spatial profiles of the MHD/Hall dynamo electric fields are measured by using Mach probe and Hall probe involving 3-axis magnetic pick-up coils. The MHD/Hall fluctuation-induced electromotive forces are large enough to sustain the mean toroidal current against the resistive decay. We have measured the electron temperature and the density with great accuracy by using a new electrostatic probe with voltage sweeping. The result shows that the electron temperature is high in the core region and low in the central open flux column (OFC), and the electron density is highest in the OFC region. The Hall dynamo becomes more dominant in a lower density region compared to the MHD dynamo. In addition, the fluctuation-induced Maxwell and Reynolds stresses are calculated to examine the fast radial transport of momentum from the OFC to the core region during the dynamo drive.

Hirono, H.; Hanao, T.; Hyobu, T.; Ito, K.; Matsumoto, K.; Nakayama, T.; Kikuchi, Y.; Fukumoto, N.; Nagata, M.

2012-10-01

399

Thermal transport in thin films measured by time-resolved, grazing incidence x-ray diffraction.  

SciTech Connect

We use depth- and time-resolved x-ray diffraction to study thermal transport across single crystal Bi films grown on sapphire in order to determine the thermal conductivity of the film and the Kapitza conductance of the interface. Ultrafast Ti:sapphire laser pulses were used to heat the films; x-ray diffraction then measured the film's lattice expansion. Use of grazing incidence diffraction geometry provided depth sensitivity, as the x-ray angle of incidence was varied near the critical angle. The shift of the film's Bragg peak position with time was used to determine the film temperature averaged over an x-ray penetration depth that could be selected by choice of the angle of incidence. For films that were thick compared to the laser penetration depth, we observed a large temperature gradient at early times. In this case, measurements with the incident angle near or well above the critical angle were more sensitive to the film conductivity or Kapitza conductance, respectively. For thinner films, however, cooling was dominated by the Kapitza conductance at all accessible time scales.

Walko, D. A.; Sheu, Y.-M.; Trigo, M.; Reis, D. A. (X-Ray Science Division); (Univ. of Michigan,); (SLAC National Accelerator Lab.); (Stanford Univ.)

2011-01-01

400

Comparisons of ground-based total column CO2 measurements and global transport model simulations  

NASA Astrophysics Data System (ADS)

Anthropogenic emissions of greenhouse gases like CO2 and CH4 are important drivers of changes in radiative forcing and therefore climate changes. However, there remain still large uncertainties concerning the estimates of source and sink distributions of these gases to and from the atmosphere and more measurements are needed to adequately assess the problem. In 2004, the Total Carbon Column Observing Network (TCCON) was formed. It consists of ground-based Fourier Transform Spectrometer (FTS) systems all around the world that provide high-resolution near-infrared spectral data . From these spectra, it is possible to retrieve total columns of CO2, CH4, CO and several other trace gases with very high precsion. Currently, TCCON has 20 operational stations. Here, we present comparisons of timeseries of CO2 measured at different TCCON stations with modeled data gained by using the global transport model TM3. The analysis includes statistical parameters like biases, variability and correlation coefficients for both timeseries and their difference over the course of one year. In addition, we show footprints of the different TCCON stations to interpret the results. The footprint is defined as the typical area where air parcels that are observed by the station originate. The calculations were done by adapting the adjoint of the TM3 model to calculate total columns.

Niebling, Sabrina; Burjack, Ina; Feist, Dietrich

2013-04-01

401

Faraday Rotation Measurements in a Laser Initiated Discharge Channel for Ion Beam Transport  

NASA Astrophysics Data System (ADS)

The neutralized beam transport in high-current plasma channels makes them interesting for the final focusing of high-intensity beams in an inertial confinement fusion reactor. The current-density distribution inside the channel is of great interest, since it determines the focusing properties. A Faraday polarimeter is currently under construction for the laser-channel experiment at the Lawrence Berkeley National Laboratory. The setup consists of a high power cw CO2 laser and a detector of two ambient temperature HgCdTe photodetectors working in the half shadow angle principle. Expected peak rotation for 40 kA discharge current is about half a degree. The polarimeter is designed to achieve a sensitivity of 0.01^circ and a contrast of 10-3 with a risetime better than 1 ? s. Tests of the detector - amplifier system will be presented as well as first time- and space-resolved measurements of the rotation. The polarimeter will be used in conjunction with a Michelson interferometer to determine the magnetic field. Measurements will be compared with numerical simulations (CYCLOPS).

Niemann, C.; Ponce, D. M.; Yu, S. S.; Leemans, W.; Fessenden, T. J.; Dahlbacka, G.; Vandersloot, K.; Sharp, W. M.; Tauschwitz, A.

1999-11-01

402

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

SciTech Connect

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.

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

2008-02-18

403

In-situ Resistive Measurements of Graphite Oxide Reduction for Spin-Transport Based Devices  

NASA Astrophysics Data System (ADS)

In this work, the thermal reduction to graphene of single and few-layer graphite oxide (GO) was characterized as a function of time using in-situ, four-point resistivity measurements. GO was produced chemically using a modified Hummer's method and then spray deposited onto an oxidized Si wafer. 100 nm Au with a 5 nm Cr adhesion layer was thermally evaporated onto the randomly dispersed GO, and then defined lithographically into an array of four point probe contact structures. High-temperature probes were used to make contact with the samples in a furnace tube where the GO was heated to 300 C for 30 minutes under forming gas atmosphere (90% N2/10% H2). The measured conductance increased several orders of magnitude as the insulating properties of GO transitioned to the semi-metallic properties of graphene. Graphene and GO were further characterized before and after thermal reduction using atomic force microscopy (AFM) and Raman spectroscopy. We also report on similar experiments using ferromagnetic CoFe contacts for spin-dependent transport experiments.

Jewell, Ira; Huang, Chien-Chih; Smith, Sean; Mason, Ashley; Jander, Albrecht; Conley, John

2010-03-01

404

Induction of nitrate transport in maize roots, and kinetics of influx, measured with nitrogen-13. [Zea mays  

SciTech Connect

Unlike phosphate or potassium transport, uptake of nitrate by roots is induced, in part, by contact with the substrate ion. Plasmalemma influx of {sup 13}N-labeled nitrate in maize roots was studied in relation to induction of the uptake system, and the influence of short-term N starvation. Maize (Zea mays) roots not previously exposed to nitrate had a constitutive transport system (state 1), but influx increased 250% during six hours of contact with 100 micromolar nitrate, by which time the transport mechanism appeared to be fully synthesized (state 2). A three-day period of N starvation prior to induction and measurement of nitrate influx resulted in a greater capacity to transport nitrate than in unstarved controls, but this was fully expressed only if roots were kept in contact with nitrate for the six hours needed for full induction (state 2E). A kinetic analysis indicated a 160% increase in maximum influx in N-starved, induced roots with a small decrease in K{sub m}. The inducible component to nitrate influx was induced only by contact with nitrate. Full expression of the nitrate inducible transport system was dependent upon mRNA synthesis. An inhibitor of cytoplasmic protein synthesis (cycloheximide) eliminated the formation of the transport system while inhibition by chloramphenicol of mitochondrial- or plastid-coded protein synthesis had no effect. Poisoning of membrane-bound proteins effectively disabled both the constitutive and induced transport systems.

Hole, D.J.; Drew, M.C. (Texas A M Univ., College Station (USA)); Emran, A.M. (Univ. of Texas Health Science Center, Houston (USA)); Fares, Y. (Biosystec Inc., College Station, TX (USA))

1990-06-01

405

Evaluation of Alternative Methods to Prepare Porcine Adipocytes for Measurement with an Electronic Particle Number and Size Determination Apparatus1  

Microsoft Academic Search

Experimental investigations with mammalian adipose tissue require a determination of adipocyte number as a basis for expression of meta- bolic and growth data. Determination of cell size is also important in adipose tissue because the fivefold or greater variation in adipocyte diameter in most growing and adult mammals precludes simple deter- mination of cell number to interpret the biological observations.

Tim Fakler; E. O'Brian Smith; Ronald L. McNeel; Harry J. Mersmann

2010-01-01

406

Histological Estimates of Ovariole Number in Honey Bee Queens, Apis mellifera, Reveal Lack of Correlation with other Queen Quality Measures  

PubMed Central

Published estimates of the number of ovarioles found in the ovaries of honey bee, Apis mellifera L. (Hymenoptera: Apidae) queens range from 100 to 180 per ovary. Within the context of a large-scale study designed to assay the overall quality of queens obtained from various commercial sources, a simple histology-based method for accurate determination of ovariole number was developed and then applied to a sample of 75 queens. Although all 10 commercial sources evaluated provided queens with ovariole numbers within the expected range, ovariole number was found to vary significantly across sources. Overall, and within most of the individual samples, there was no correlation of ovariole number with other morphological attributes such as thoracic width, wing length, or wet weight. Queens from two of the sources, however, displayed a significant negative relationship between wet weight and ovariole number. This study provides baseline data on ovariole number in commercial honey bee queens in the United States at a time when honey bee populations are declining; the method described can be used in studies relating ovariole number in queens to egg production and behavior.

Jackson, Jeffrey T.; Tarpy, David R.; Fahrbach, Susan E.

2011-01-01

407

How to Choose the Number of Call Attempts in a Telephone Survey - in the Presence of Nonresponse and Measurement Errors  

Microsoft Academic Search

In telephone surveys, several call attempts are often needed to establish contact with selected individuals. We consider the problem of choosing the maximum number of call attempts to be made to each selected individual before he or she is classified as unavailable. This is an important question since a large number of call attempts makes the data collection costly and

Annica Isaksson; Peter Lundquist; Daniel Thorburn

408

Spin-polarized transport current in n-type codoped ZnO thin films measured by Andreev spectroscopy.  

SciTech Connect

We use point-contact Andreev-reflection measurements to determine the spin polarization of the transport current in pulse laser deposited thin films of ZnO with 1% Al and with and without 2% Mn. Only films with Mn are ferromagnetic and show spin polarization of the transport current of up to 55 {+-} 0.5% at 4.2 K, in sharp contrast to measurements of the nonmagnetic films without Mn where the polarization is consistent with zero. Our results imply strongly that ferromagnetism in these Al-doped ZnO films requires the presence of Mn.

Yates, K. A.; Behan, A. J.; Neal, J. R.; Score, D. S.; Blythe, H. J.; Gehring, G. A.; Heald, S. M.; Branford, W. R.; Cohen, L. F.; Imperial Coll.; Univ. of Sheffield

2009-12-01

409

The Aerothermodynamic Measurement System for Future Experimental and Operational Space Transportation Systems  

NASA Astrophysics Data System (ADS)

In the frame of the German national technology program ASTRA an Aerothermodynamic Measurement System (AMS) was further developed. The system was originally designed and flight-qualified for use in the X-38 re-entry vehicle. The objective of the project was to extend the temperature range for application and the number of physical quantities, which can be measured. In addition the resulting system should be adaptable to a multiplicity of different thermal protection systems. This paper summarizes the most recent status of the new AMS design, development and qualification, including • a brief set of main requirements; • the system variants; • a conceptual system design overview; • the qualification program and test results; • and a look-out to potential applications.

Peters, L.

2005-02-01

410

Laser-based measurements of magnetic fluctuation-induced particle transport and nonlinear mode interactions in the Madison Symmetric Torus reversed-field pinch  

NASA Astrophysics Data System (ADS)

Magnetic fluctuation-induced particle transport and density fluctuations have been investigated in the Madison Symmetric Torus (MST) reversed-filed pinch using a far infrared (FIR) laser based interferometer-polarimetry system. An extensive study focuses on the particle transport and density fluctuations during the sawtooth crash where the stochastic magnetic field is largest. Particle flux arising from the inieraction between density fluctuations and magnetic fluctuations has been measured to be significant at the reversal surface where modes with poloidal mode number m = 0 are resonant. The particle flux is comparable to that measured in the core where m = 1 modes dominate. The origin of density fluctuations has been studied experimentally. It is found that density fluctuations not only result from linear advection but also non-linear three-wave interactions. This is different from the previously reported results that indicated that the edge density fluctuations originate from linear advection. The results reported here reveal that m = 0 modes play an important role in density fluctuations and particle flux. An experiment where m = 0 modes are greatly reduced, by removing the reversal surface from the plasma, indicates that particle flux and density fluctuations are reduced significantly, which further confirms the importance of edge resonant modes in particle transport.

Yates, Travis Fred

411

Transport Measurements of Ohmic and RF-Heated Plasmas in CDX-U  

NASA Astrophysics Data System (ADS)

Multiple aspects of plasma transport in the CDX-U spherical torus (ST) are explored in plasmas with up to 200 kW of auxiliary high-harmonic fast-wave (HHFW) heating. Recent CDX-U diagnostic upgrades include a 12-point Thomson scattering system, a 10-channel bolometer array, a 10-channel multilayer mirror (MLM) array, and a single-chord MOSS spectrometer. A time-resolved electron Bernstein wave (EBW) temperature diagnostic is under development. The focus is largely towards the interplay between ST and RF-heating effects on electron thermal transport and impurity particle transport. Experimental data is integrated using the TRANSP tokamak transport code.

Munsat, T.; Leblanc, B.; Efthimion, P.; Jones, B.; Kaita, R.; Kugel, H.; Majeski, R.; Menard, A.; Post-Zwicker, A.; Rosenberg, J.; Spaleta, G.; Taylor, V.; Soukhanovskii, D.; Stutman, D.; Hoffman, T.; Miller

1999-11-01

412

Importance-Assessing Method with Fuzzy Number-Valued Fuzzy Measures and Discussions on TFNs And TrFNs  

Microsoft Academic Search

The weight is one of the most useful tools to measure the attribute importance when individuals make a decision or evaluate the alternatives. Among the methods which measure the weight, fuzzy measures is are subjective scales for the degrees of fuzziness and widely used to determine the degrees of subjective importance of evaluation items in numerous studies for the time

Ting-Yu Chen; Tai-Chun Ku

2008-01-01

413

Development of a Surface Magneto-Transport Measurement System with Multi-Probes and the In situ Measurement of Bi Nanofilms Prepared on Si(111)7×7  

Microsoft Academic Search

We have developed an independently-driven double probe-stage system that enables in situ magneto-transport measurements on surfaces and ultrathin films, prepared in ultrahigh vacuum. The measurements can be made at temperature down to 7.6 K and under magnetic field up to 7 T. The demonstration of Bi(001) crystal nanofilms on the Si(111)7×7 surface is presented.

Nobuhiro Miyata; Rei Hobara; Hisashi Narita; Toru Hirahara; Shuji Hasegawa; Iwao Matsuda

2011-01-01

414

A time-resolved measurement technique for particulate number density in diesel exhaust using a fast-response flame ionization detector  

Microsoft Academic Search

The fast-response flame ionization detector (FRFID) has been used widely to measure, in real time, the concentration of unburnt hydrocarbons in internal combustion engines. In this study, a FRFID is modified to measure, simultaneously, the concentration of the gaseous hydrocarbons and the number density of soot particulates present in the exhaust of a turbocharged Dl diesel engine. The system is

J. H. Sun; S. H. Chan

1997-01-01

415

In situ measurements of aerosol optical properties and number size distributions in a coastal region of Norway during the summer of 2008  

NASA Astrophysics Data System (ADS)

In situ measurements of aerosol optical properties and particle size distributions were made in the summer of 2008 at the ALOMAR station facility (69°16' N, 16°00' E), located in a rural site in the north of the island of Andøya (Vesterålen archipelago), approximately 300 km north of the Arctic Circle. The extended three-month campaign was part of the POLARCAT Project (Polar Study using Aircraft, Remote Sensing, Surface Measurements and Models, of Climate, Chemistry, Aerosols, and Transport) of the International Polar Year (IPY-2007-2008). Our goal was to characterize the aerosols of this sub-Arctic area, which are frequently transported to the Arctic region. Data from 13 June to 26 August 2008 were available and the statistical data for all instruments were calculated based on the hourly averages. The overall data coverage was approximately 72%. The hourly mean values of the light-scattering coefficient, ?s, and the light-absorption coefficient, ?a, at 550 nm were 5.41 Mm-1 (StD = 3.55 Mm-1) and 0.40 Mm-1 (StD = 0.27 Mm-1), respectively. The scattering/absorption Ångström exponents, ?s,a, were used in a detailed analysis of the variations of the spectral shape of ?s,a. While ?s indicates the presence of two particle sizes corresponding to two types of aerosols, ?a indicates only one type of absorbing aerosol particle. ?a values greater than 1 were not observed. The single-scattering albedo, ?0, ranged from 0.62 to 0.99 (mean = 0.91, StD = 0.05), and the relationships between this parameter and the absorption/scattering coefficients and the Ångström exponents are presented. Any absorption value may lead to the lowest values of ?0, whereas only the lowest scattering values were observed in the lowest range of ?0. For a given absorption value, lower ?0 were observed for smaller ?s. The submicrometer, micrometer and total concentrations of the particles presented hourly mean values of 1277 cm-3 (StD = 1563 cm-3), 1 cm-3 (StD = 1 cm-3) and 2463 cm-3 (StD = 4251 cm-3), respectively, and the modal correlations were also investigated. The optical and microphysical parameters, as well as their relationship with each other, are reported. ?s correlated strongly with the number concentration of accumulation mode particles and more strongly with the micrometer fraction of particles, but weak correlations were observed for the Aitken and nucleation modes. The origins and pathways of the air masses were examined, and based on sector classification, a relationship between the air mass origin, the optical parameters and the size distributions was established. The low values of the optical and microphysical parameters indicate that the predominant regional aerosol is mostly clean and the shape of the size distribution is characterized by bimodal median size distributions. However, the relationships between the air mass origins and the parameters studied allow us to describe two characteristic situations: the one of the northern and western air masses, which were predominantly composed of marine aerosols and presented the lowest optical and microphysical values observed, indicating predominantly non-absorbent and coarser particles; and the one of the eastern and southern air masses, in which continental aerosols were predominant and exhibited higher values for all parameters, indicating the presence of smaller absorbent particles. The north-northeastern air masses presented the strongest Aitken mode, indicating more recently formed particles, and the southeastern air masses presented the strongest accumulation mode (however, the southeastern air masses were the least common, accounting for only 3% of occurrences).

Mogo, S.; Cachorro, V. E.; Lopez, J. F.; Montilla, E.; Torres, B.; Rodríguez, E.; Bennouna, Y.; de Frutos, A. M.

2012-07-01

416

Synthesis and Transport Measurements of Catalyst-Free Topological Insulator Bi2Se3 Nanostructures  

NASA Astrophysics Data System (ADS)

The semiconductor bismuth selenide (Bi2Se3) was predicted to be a topological insulator (TI) with a single Dirac cone, which was observed using Angle-Resolved-Photo-Emission-Spectroscopy in 2008. TI's are materials which exhibit electrically insulating properties in the bulk, but they have metallic surface states. The surface states are topologically protected from perturbations, defects, and impurities. Nano-sized structures might be well suited for the study of surface states because the surface effects are likely to dominate over bulk properties due to the high surface-to-volume ratio. So far, nanowires and nanoribbons of TI s have been synthesized using metal catalysts, such as gold, iron, or nickel. However, it has been found that these catalysts dope the nanostructures, which has the potential to modify their properties. We show catalyst-free growth of nanowires and nanoribbons of Bi2Se3 using the Vapor-Liquid-Solid method. Analysis by EDAX and TEM imaging suggest high purity samples. We have fabricated devices from these nanostructures and present electron transport measurements.

Mlack, Jerome T.; Rahman, Atikur; Johns, Gary L.; Markovic, Nina

2012-02-01

417

Simultaneous measurement of extracellular dopamine and dopamine transporter occupancy by cocaine analogs in squirrel monkeys.  

PubMed

Several classes of drugs bind to the dopamine transporter (DAT) with high affinity, but some are weaker positive reinforcers than cocaine, suggesting that affinity for and occupancy of the DAT is not the only determinant of a drug's reinforcing effectiveness. Other factors such as the rate of onset have been positively and strongly correlated with the reinforcing effects of DAT inhibitors in nonhuman primates. In the current studies, we examined the effects of acute systemic administration of cocaine and three cocaine analogs (RTI-150, RTI-177, and RTI-366) on binding to DAT in squirrel monkey brain using positron emission tomography (PET) neuroimaging. During the PET scan, we also measured drug effects on dopamine (DA) levels in the caudate using in vivo microdialysis. In general, our results suggest a lack of concordance between drug occupancy at DAT and changes in DA levels. These studies also indicate that acute cocaine administration decreases the availability of plasma membrane DAT for binding, even after cocaine is no longer blocking DA uptake as evidence by a return to basal DA levels. PMID:22237864

Kimmel, Heather L; Nye, Jonathon A; Voll, Ronald; Mun, Jiyoung; Stehouwer, Jeffrey; Goodman, Mark M; Votaw, John R; Carroll, F I; Howell, Leonard L

2012-03-16

418

Dopamine transporter genotype predicts behavioural and neural measures of response inhibition.  

PubMed

The ability to inhibit unwanted actions is a heritable executive function that may confer risk to disorders such as attention deficit hyperactivity disorder (ADHD). Converging evidence from pharmacology and cognitive neuroscience suggests that response inhibition is instantiated within frontostriatal circuits of the brain with patterns of activity that are modulated by the catecholamines dopamine and noradrenaline. A total of 405 healthy adult participants performed the stop-signal task, a paradigmatic measure of response inhibition that yields an index of the latency of inhibition, termed the stop-signal reaction time (SSRT). Using this phenotype, we tested for genetic association, performing high-density single-nucleotide polymorphism mapping across the full range of autosomal catecholamine genes. Fifty participants also underwent functional magnetic resonance imaging to establish the impact of associated alleles on brain and behaviour. Allelic variation in polymorphisms of the dopamine transporter gene (SLC6A3: rs37020; rs460000) predicted individual differences in SSRT, after corrections for multiple comparisons. Furthermore, activity in frontal regions (anterior frontal, superior frontal and superior medial gyri) and caudate varied additively with the T-allele of rs37020. The influence of genetic variation in SLC6A3 on the development of frontostriatal inhibition networks may represent a key risk mechanism for disorders of behavioural inhibition. PMID:21876545

Cummins, T D R; Hawi, Z; Hocking, J; Strudwick, M; Hester, R; Garavan, H; Wagner, J; Chambers, C D; Bellgrove, M A

2011-08-30

419

High Quality Nanogap Electrodes for Electronic Transport Measurements of Single Molecules  

NASA Astrophysics Data System (ADS)

Electromigrated metal electrodes and resulting devices have shown great promise in moving towards the realization of single molecule-based electronic devices holding the potential for a wide range of electronic applications. At present, a major concern is that the electronic behavior of such devices may be greatly influenced by residual nanoscale metal particles. We have developed a computer controlled electromigration (CCE) process for creating nanogaps at room temperature which allows us to characterize a bare nanogap before putting a molecule into the nanogap.^1 This is very different from other approaches used in the field where nanogaps are formed at low temperature with molecules already attached to the nanowire by employing a simple ramp up in voltage. Among the bare nanogaps we produced using CCE, tunneling behavior is observed with no indication of transport signatures associated with metal particle formation. Details of molecular measurements utilizing these clean gaps will be discussed. This work was supported by the National Science Foundation (NIRT Grant No. 0304531 and MRSEC award DMR05-20020). ^1D. R. Strachan, D. E. Smith, D. E. Johnston et al., Appl. Phys. Lett. 86 043109 (2005).

Johnston, Danvers E.; Strachan, Douglas R.; Guiton, Beth S.; Davies, Peter K.; Park, Tae Hong; Therien, Michael J.; Johnson, A. T. Charlie

2007-03-01

420

Neutron imaging technique for in situ measurement of water transport gradients within Nafion in polymer electrolyte fuel cells  

Microsoft Academic Search

Water transport is an important consideration in the optimization of polymer electrolyte fuel cell (PEFC) performance, affecting both internal resistance and cathode polarization losses. Novel experiments are described using neutron radiography to measure water gradient profiles within Nafion{reg_sign} in an operating PEFC. Preliminary neutron intensity gradients show qualitative agreement with the expected response of membrane water content to changes in

R. J. Bellows; M. Y. Lin; M. Arif; A. K. Thompson; D. Jacobson

1999-01-01

421

Source evaluation of aerosols measured during the Indian Ocean Experiment using combined chemical transport and back trajectory modeling  

Microsoft Academic Search

This work presents an analysis of aerosol measurements made during the Oceanographic Research Vessel Sagar Kanya cruise of January–March 1999, in the Indian Ocean Experiment intensive field phase (INDOEX-IFP), with regard to the aerosol chemical constituents and identification of source regions of their origin. This is done through a hybrid approach which uses an Eulerian forward transport calculation in a

S. Verma; C. Venkataraman; O. Boucher; S. Ramachandran

2007-01-01

422

Selectivity in vector management: an investigation of the effectiveness of measures used to prevent transport of non-indigenous species  

Microsoft Academic Search

Measures taken to control the spread of non-indigenous species by human vectors may act selectively by providing effective protection against some (but not all) species. Toxic ‘antifouling paints’ are used by boat owners to prevent the development of ‘fouling assemblages’ on the hulls of their boats, which reduce vessel speed and maneuverability. By reducing fouling, these paints also prevent transport

Oliver Floerl; Graeme J. Inglis; Helene M. Marsh

2005-01-01

423

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

NASA Astrophysics Data System (ADS)

Different experimental schemes for investigation of warm dense matter produced with intense energetic ion beams are presented. T