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1

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

PubMed

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

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

2013-01-01

2

Probe ion diffusivity measurements in salt-in-polymer electrolytes: Stokes radii and the transport number problem  

Microsoft Academic Search

In order to explore the factors which distinguish ionic motions in salt-in-polymer electrolytes from those in molecular and aqueous solvents, self-diffusivity measurements of cations and anions have been made utilizing the electrochemical technique of chronoamperometry. Stokes` law radii have been calculated using both the macroscopic and microscopic solvent viscosities and found to differ greatly from the crystal radii. The friction

M. G. McLin; C. A. Angell

1996-01-01

3

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

4

CONFINEMENT IN THE RFP: LUNDQUIST NUMBER SCALING, PLASMA FLOW, AND REDUCED TRANSPORT  

E-print Network

1 CONFINEMENT IN THE RFP: LUNDQUIST NUMBER SCALING, PLASMA FLOW, AND REDUCED TRANSPORT G. Fiksel,1 heat and particle transport in the reversed field pinch (RFP) result primarily from large RFP development issues. We report measurements of the Lundquist number scaling (S-scaling) of magnetic

Wisconsin at Madison, University of

5

Off-Design Reynolds Number Effects for a Supersonic Transport  

NASA Technical Reports Server (NTRS)

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

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

2005-01-01

6

Suspended-sediment transport measurement  

USGS Publications Warehouse

Of the two operationally defined phases of fluvial-sediment transport – suspended load and bedload – collection of suspended-load data is the more common. This is a reflection of a number of factors including the general predominance of suspended load over bedload in mass transport and the greater difficulty and costs associated with collecting bedload data. Acquisition of suspended-sediment data for sediment-transport computations requires collection of water-sediment samples that represent, or can be reliably adjusted to represent, the mean discharge-weighted concentration and particle-size distribution in a cross section at the time of sample collection. Analytical results from a sufficient number of representative samples obtained with concurrent water-discharge values are needed to compute suspended-sediment discharge for the period of interest.

Gray, John R.

2007-01-01

7

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. PMID:20980309

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

2010-01-01

8

Particle Measurement Methods. Number Concentrations. One common method used to measure number concentrations  

E-print Network

. Pulses are counter by an electronic counter and summed over some period of time. Number concentration canParticle Measurement Methods. Number Concentrations. One common method used to measure number concentrations of all ambient particles is the Condensation Particle Counter (CPC, also called Condensation

Weber, Rodney

9

Absolute number concentration measurement of submicrometer particles  

SciTech Connect

Condensation nuclei in the atmosphere are known to be an important factor in the development of clouds, the occurrence of rainfall, and the formation of particulate air pollutions that can cause undesirable effects on man and his environment. Condensation nuclei are invisible and numerous, and their number concentration has become the characteristic of interest and has been widely studied since the development of the first condensation nuclei counter by Aitken in 1888. A conventional nuclei counter employs the so-called condensation technique which enables the minute nuclei to grow, in a supersaturated environment, to ..mu..m-sized droplets; the number concentration of the visible droplets is then measured. Since each nucleus grows to a droplet, the number concentration of droplets and nuclei remains the same. The number of droplets is measured by (1) direct observation with a microscope (direct counter), (2) counting from photographs of the droplets (photographic counter), (3) suitably calibrated light transmission (or scattering) measurement (relative photoelectric counter). Most of the widely-used counters are relative counters in which the instrument reading must be calibrated against a direct or photographic counter. A new condensation nuclei counter is described which is designed to have the following advantages over the widely-used counters: (a) It provides an absolute concentration measurement. (b) Even a small random fluctuation of nuclei concentration can immediately be detected.

Chen, T.H.B.

1982-01-01

10

Baryon Number Transport in a Cosmic QCD-Phase Transition  

E-print Network

We investigate the transport of baryon number across phase boundaries in a putative first order QCD-phase transition. Two independent phenomenological models are employed to estimate the baryon penetrability at the phase boundary: chromoelectric flux tube models; and an analogy to baryon-baryon coalescence in nuclear physics. Our analysis indicates that baryon transport across phase boundaries may be order of magnitude more efficient than other work has suggested. We discuss the substantial uncertainties involved in estimating baryon penetrability at phase boundaries.

K. Jedamzik; G. M. Fuller

1994-08-24

11

Comparative determination of effective transport numbers in solid lithium electrolytes  

NASA Astrophysics Data System (ADS)

A comparison of the effective transport numbers t+ of the lithium cation in immobilized liquid electrolytes, obtained by mixing molar solutions of LiClO 4 in propylene carbonate with varying amounts and types of highly-dispersed pyrogenic silica is presented. The results vary from 0.1 to 0.4 as determined by (i) a.c. complex impedance spectroscopy; (ii) isothermal transient ionic current method; (iii) steady-state current method, and (iv) Tubandt method. Main object of this study was to evaluate the value of the four methods as simple, practiclly useful measn to check effective cationic transport numbers of ionic conductors without extensive ion aggregation.

Fritz, H. P.; Kuhn, A.

12

VOLUME 82, NUMBER 24 P H Y S I C A L R E V I E W L E T T E R S 14 JUNE 1999 Measurement of Cross-Magnetic-Field Heat Transport in a Pure Ion Plasma  

E-print Network

measure col- lisional heat transport in a quiescent pure ion plasma. Direct Coulomb collisions betweenVOLUME 82, NUMBER 24 P H Y S I C A L R E V I E W L E T T E R S 14 JUNE 1999 Measurement of Cross-Magnetic-Field Heat Transport in a Pure Ion Plasma E. M. Hollmann, F. Anderegg, and C. F. Driscoll Physics Department

California at San Diego, University of

13

Love number can be hard to measure  

NASA Astrophysics Data System (ADS)

The waveform phase for a neutron star binary can be split into point-particle terms and finite-size terms (characterized by the Love number) that account for equation-of-state effects. The latter first enter at fifth post-Newtonian (5PN) order (i.e., proportional to the tenth power of the orbital velocity), but the former are only known completely to 3.5PN order, with higher-order terms only known to leading order in the mass ratio. We here find that not including point-particle terms at 4PN order to leading and first order in the mass ratio in the template model can severely deteriorate our ability to measure the equation of state. This problem can be solved if one uses numerical waveforms once their own systematic errors are under control.

Yagi, Kent; Yunes, Nicolás

2014-01-01

14

Sediment transport measurements: Chapter 5  

USGS Publications Warehouse

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

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

2008-01-01

15

Low Peclet number mass and momentum transport in microcavities  

NASA Astrophysics Data System (ADS)

For the informed design of microfluidic devices, it is important to understand transport phenomena at the microscale. This letter outlines an analytically driven approach to the design of rectangular microcavities extending perpendicular to a perfusion microchannel for applications that may include microfluidic cell culture devices. We present equations to estimate the transition from advection- to diffusion-dominant transport inside cavities as a function of the geometry and flow conditions. We also estimate the time required for molecules, such as nutrients or drugs, to travel from the microchannel to a given length into the cavity. These analytical predictions can facilitate the rational design of microfluidic devices to optimize and maintain long-term, low Peclet number environments with minimal fluid shear stress.

Yew, A. G.; Pinero, D.; Hsieh, A. H.; Atencia, J.

2013-02-01

16

The Transport Number of Silver Fluoride Using a Pulsating Current  

E-print Network

solution. + — A 6 C p i gu I Pass one faraday of electricity through the cell. If X is the transport number, the follow- ing changes take place in A* 1 equivalent of Ag+ formed from anode. (1 - X) equivalents of Ag4" pass to B. X equivalents of NOj...-* enter from B. Iri B. (1 - X) equivalents of Ag^ ~ enter from A. (1 - X) equivalents of Ag4" pass to C. X equivalents of N03~enter from C. X equivalents of N03~pass to A. In 0. (1 - X) equivalents of Ag+ enter from B. 1 equivalent of Ag...

Parkhurst, I. P.

1914-06-05

17

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

Microsoft Academic Search

The closure problem in chemically reacting turbulent flows would be solved when velocity, temperature and number density (transport variables) are known. The transport variables provide input to momentum, heat and mass transport equations leading to analysis of turbulence-chemistry interaction, providing a pathway to improve combustion efficiency. There are no measurement techniques to determine all three transport variables simultaneously. This paper

Nigil Satish Jeyashekar; John Seiner

2006-01-01

18

SALEM NUMBERS, PISOT NUMBERS, MAHLER MEASURE AND GRAPHS JAMES MCKEE AND CHRIS SMYTH  

E-print Network

SALEM NUMBERS, PISOT NUMBERS, MAHLER MEASURE AND GRAPHS JAMES MCKEE AND CHRIS SMYTH ABSTRACT. We use graphs to define sets of Salem and Pisot numbers, and prove that the union of these sets is closed, supporting a conjecture of Boyd that the set of all Salem and Pisot numbers is closed. We find all trees

Smyth, Chris

19

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

20

Ranking of Intuitionistic Fuzzy Numbers by New Distance Measure  

E-print Network

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

Debaroti Das; P. K. De

2014-10-27

21

40 CFR 51.213 - Transportation control measures.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 false Transportation control measures. 51.213 Section 51... § 51.213 Transportation control measures. (a) The plan must...implementing transportation control measures. (b) In the case...

2010-07-01

22

40 CFR 51.213 - Transportation control measures.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 false Transportation control measures. 51.213 Section 51... § 51.213 Transportation control measures. (a) The plan must...implementing transportation control measures. (b) In the case...

2013-07-01

23

40 CFR 51.213 - Transportation control measures.  

Code of Federal Regulations, 2011 CFR

...2011-07-01 false Transportation control measures. 51.213 Section 51... § 51.213 Transportation control measures. (a) The plan must...implementing transportation control measures. (b) In the case...

2011-07-01

24

40 CFR 51.213 - Transportation control measures.  

Code of Federal Regulations, 2012 CFR

...2012-07-01 false Transportation control measures. 51.213 Section 51... § 51.213 Transportation control measures. (a) The plan must...implementing transportation control measures. (b) In the case...

2012-07-01

25

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

NASA Astrophysics Data System (ADS)

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

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

2014-01-01

26

Quantum nondemolition measurement of small photon numbers using stored light  

NASA Astrophysics Data System (ADS)

We propose a scheme for realizing a quantum nondemolition (QND) measurement of a small number of optical photons. Our scheme has two stages: First, we couple a propagating light pulse with fixed photon number to a trapped cold atomic gas within a cavity, such that the pulse is stored within a collective polariton mode. Second, a small-photon-number measurement is engineered by monitoring the cavity-transmission spectrum. Since the polariton mode profile is preserved during the process of detecting the spectrum, photon-number QND measurements could be achieved by retrieving the light pulse from the polariton mode. We also discuss a method which uses QND measurements to generate small-photon Fock states.

Liang, L.; Lin, G. W.; Hao, Y. M.; Niu, Y. P.; Gong, S. Q.

2014-11-01

27

On Measurements, Numbers and p-Adic Mathematical Physics  

E-print Network

In this short paper I consider relation between measurements, numbers and p-adic mathematical physics. p-Adic numbers are not result of measurements, but nevertheless they play significant role in description of some systems and phenomena. We illustrate their ability for applications referring to some sectors of p-adic mathematical physics and related topics, in particular, to string theory and the genetic code.

Branko Dragovich

2012-05-23

28

Transportable calorimeter measurements of highly enriched uranium  

SciTech Connect

A sensitive calorimeter has been combined with a small temperature-controlled water bath to compose a transportable system that is capable of measuring multikilogram quantities of highly enriched uranium (HEU). The sample chamber size, 5 in. in diameter by 10 in. high, is large enough to hold sufficient HEU metal or high-grade scrap to provide a measurable thermal signal. Calorimetric measurements performed on well-characterized material indicate that the thermal power generated by 93% {sup 235}U samples with 1.0% {sup 234}U can be measured with a precision of about 1% (1 sigma) for 4-kg samples. The transportable system consists of a twin-bridge calorimeter installed inside a 55-gal. stainless steel drum filled with water with heating and cooling supplied by a removable thermoelectric module attached to the side. Isotopic measurements using high-resolution gamma-ray measurements of the HEU samples and analysis with the FRAM code were used to determine the isotopic ratios and specific power of the samples. This information was used to transform the measured thermal power into grams of HEU. Because no physical standards are required, this system could be used for the verification of plutonium, {sup 238}Pu heat sources, or large quantities of metal or other high-grade matrix forms of HEU.

Rudy, C.; Bracken, D.S.; Staples, P.; Carrillo, L.

1997-11-01

29

Diagnostics for Radial Electron Thermal Transport Measurements  

NASA Astrophysics Data System (ADS)

Production and identification of electron temperature gradient (ETG) mode have been successfully demonstrated in a basic experiment in Columbia Linear Machine CLM [1]. ETG mode was excited by heating electrons of the core plasma. For local measurement of radial electron thermal transport we use miniature langmuir probes with special resolution < 1mm and frequency response > 2MHz. Triple probes will be used to measure local temperature fluctuations. For significant improvement of the frequency response of the triple probe we used a capacitive probe as a single probe and used capacitive coupling of double probe's positive tip with the measuring circuit. Then cross- correlation of the electron temperature fluctuations and potential fluctuations will yield local thermal flux. A non-local measurement scheme based on a variation of perturbative transport method is attempted. Here we modulate (at ˜ 20-50kHz) the accelerating bias voltage which produces the electron heating. The resulting modulated Te in the plasma core will be conducted / convected to the plasma edge, where it will be measured by a triple probe. [1] X. Wei, V. Sokolov and A.K. Sen, Bulletin of 49th APS DPP, p.110, 2007.

Sokolov, Vladimir; Wei, Xiao; Sen, Amiya K.

2008-11-01

30

VOLUME 87, NUMBER 21 P H Y S I C A L R E V I E W L E T T E R S 19 NOVEMBER 2001 Thermal Transport Measurements of Individual Multiwalled Nanotubes  

E-print Network

structures were fabricated on a silicon nitride/silicon oxide/silicon multilayer by electron beam film resistor, fabricated by electron beam lithography, serves as a heater to increase the temperature) The thermal conductivity and thermoelectric power of a single carbon nanotube were measured using

Kim, Philip

31

Statistical measures and magic numbers in metal clusters  

NASA Astrophysics Data System (ADS)

In this work, a shell model for metal clusters up to 220 valence electrons is used to obtain the fractional occupation probabilities of the electronic orbitals. Then, the calculation of a statistical measure of complexity and the Fisher-Shannon information is carried out. An increase of both magnitudes with the number of valence electrons is observed. The shell structure is reflected by the behavior of the statistical complexity. The magic numbers are indicated by the Fisher-Shannon information. So, as in the case of atomic nuclei, the study of statistical indicators also unveil the existence of magic numbers in metal clusters.

Sañudo, Jaime; López-Ruiz, Ricardo

2011-04-01

32

Dopamine transporter, gender, and number of sexual partners among young adults  

Microsoft Academic Search

The dopamine transporter gene (DAT1) codes for a dopamine transporter protein, which limits the level and duration of dopamine receptor activation. The DAT1 gene is a strong candidate gene for reward-seeking behavior. This article reports compelling evidence for the association between the 40 bp variable number of tandem repeats in the DAT1 gene and the self-reported number of sexual partners

Guang Guo; Yuying Tong; Cui-Wei Xie; Leslie A Lange; G Guo

2007-01-01

33

Heating from Continuous Number Density Measurements in Optical Lattices  

E-print Network

We explore the effects of continuous number density measurement on atoms in an optical lattice. By integrating a master equation for quantum observables, we calculate how single particle correlations decay. We consider weakly- and strongly- interacting bosons and noninteracting fermions. Even in the Mott regime, such measurements destroy correlations and increase the average energy, as long as some hopping is allowed. We explore the role of spatial resolution, and find that the heating rate is proportional to the amount of information gained from such measurements.

Yariv Yanay; Erich J. Mueller

2014-05-19

34

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

35

Optical measurement techniques for high Reynolds number train investigations  

NASA Astrophysics Data System (ADS)

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 part of the German Dutch wind tunnel association (DNW). The adaptation and application of three optical measurement techniques for such high Reynolds number investigations is described in the article. The optical methods are: Particle Image Velocimetry for the measurement of velocity fields, Background Oriented Schlieren technique for density gradient measurements, and a white light Digital Speckle Photography technique for model deformation monitoring.

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

2006-04-01

36

Intensive statistical complexity measure of pseudorandom number generators  

NASA Astrophysics Data System (ADS)

A Statistical Complexity measure has been recently proposed to quantify the performance of chaotic Pseudorandom number generators (PRNG) (Physica A 354 (2005) 281). Here we revisit this quantifier and introduce two important improvements: (i) consideration of an intensive statistical complexity (Physica A 334 (2004) 119), and (ii) following the prescription of Brand and Pompe (Phys. Rev. Lett. 88 (2002) 174102-1) in evaluating the probability distribution associated with the PRNG. The ensuing new measure is applied to a very well-tested PRNG advanced by Marsaglia.

Larrondo, H. A.; González, C. M.; Martín, M. T.; Plastino, A.; Rosso, O. A.

2005-10-01

37

Entanglement, number fluctuations and optimized interferometric phase measurement  

NASA Astrophysics Data System (ADS)

We derive a phase-entanglement criterion for two bosonic modes that is immune to number fluctuations, using the generalized Moore-Penrose inverse to normalize the phase-quadrature operator. We also obtain a phase-squeezing criterion that is immune to number fluctuations using similar techniques. These are used to obtain an operational definition of relative phase-measurement sensitivity via the analysis of phase measurement in interferometry. We show that these criteria are proportional to the enhanced phase-measurement sensitivity. The phase-entanglement criterion is the hallmark of a new type of quantum-squeezing, namely planar quantum-squeezing. This has the property that it squeezes simultaneously two orthogonal spin directions, which is possible owing to the fact that the SU(2) group that describes spin symmetry has a three-dimensional parameter space of higher dimension than the group for photonic quadratures. A practical advantage of planar quantum-squeezing is that, unlike conventional spin-squeezing, it allows noise reduction over all phase angles simultaneously. The application of this type of squeezing is to the quantum measurement of an unknown phase. We show that a completely unknown phase requires two orthogonal measurements and that with planar quantum-squeezing it is possible to reduce the measurement uncertainty independently of the unknown phase value. This is a different type of squeezing compared to the usual spin-squeezing interferometric criterion, which is applicable only when the measured phase is already known to a good approximation or can be measured iteratively. As an example, we calculate the phase entanglement of the ground state of a two-well, coupled Bose-Einstein condensate, similarly to recent experiments. This system demonstrates planar squeezing in both the attractive and the repulsive interaction regime.

He, Q. Y.; Vaughan, T. G.; Drummond, P. D.; Reid, M. D.

2012-09-01

38

A device for measuring sonic velocity and compressor Mach number  

NASA Technical Reports Server (NTRS)

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

Huber, Paul W; Kantrowitz, Arthur

1947-01-01

39

MEASURING THE ANS IN CHILDREN Measuring the Approximate Number System in children: Exploring the  

E-print Network

MEASURING THE ANS IN CHILDREN 1 Measuring the Approximate Number System in children: Exploring the relationships among different tasks THE ANS IN CHILDREN 2 Abstract Research has demonstrated that children

Inglis, Matthew

40

Integrating Sustainable Transport Measures into the Clean Development Mechanism  

Microsoft Academic Search

While the number of projects under the Clean Development Mechanism (CDM) is expanding rapidly, there currently are relatively few transport projects in the global CDM portfolio. This article examines existing CDM transport projects and explores whether sectoral approaches to the CDM may provide a better framework for transport than the current project?based CDM. We ask: Would a sectoral approach to

Bettina Wittneben; Daniel Bongardt; Holger Dalkmann; Wolfgang Sterk; Christian Baatz

2009-01-01

41

Spatially Resolved Ballistic Optoelectronic Transport Measured by Quantized  

E-print Network

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

Ludwig-Maximilians-Universität, München

42

Numbers  

NSDL National Science Digital Library

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

Edkins, Jo

2006-01-01

43

Flow Visualization of Low Prandtl Number Fluids using Electrochemical Measurements  

NASA Technical Reports Server (NTRS)

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

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

2003-01-01

44

Slow potential changes due to transport number effects in cells with unstirred membrane invaginations or dendrites  

Microsoft Academic Search

Summary Many neurones are extremely invaginated and possess branching processes, axons and dendrites. In general, they are surrounded by a restricted diffusion space. Many of these cells exhibit large, slow potential changes during the passage of current across their membranes. Whenever currents cross membranes separating aqueous solutions, differences in transport numbers of the major permeant ions give rise to local

Peter H. Barry

1984-01-01

45

Measured Local Heat Transport in Turbulent Rayleigh-Benard Convection X.-D. Shang,1  

E-print Network

Measured Local Heat Transport in Turbulent Rayleigh-Be´nard Convection X.-D. Shang,1 X.-L. Qiu,2 P of the measured Nusselt number (nor- malized heat flux), Nu(Ra,Pr), as a function of the two experimental control of the convection cell. Direct measurements of the local convective heat flux, therefore, become essential

Tong, Penger

46

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...

47

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...

48

Using Transportation Distances for Measuring Melodic Similarity  

E-print Network

) and the Proportional Transportation Distance (PTD), a pseudo­metric for weighted point sets which is based on the EMD. A comparison of our experiment results with earlier work shows that by using weighted point sets and the EMD/PTD also used a modified version of it, the Proportional Transportation Distance (PTD), which was proposed

Utrecht, Universiteit

49

Using Transportation Distances for Measuring Melodic Similarity  

E-print Network

) and the Proportional Transportation Distance (PTD), a pseudo-metric for weighted point sets which is based on the EMD. A comparison of our experiment results with earlier work shows that by using weighted point sets and the EMD/PTD also used a modified version of it, the Proportional Transportation Distance (PTD), which was proposed

Veltkamp, Remco

50

Transportation in reverse logistics enterprise: a comprehensive performance measurement methodology  

Microsoft Academic Search

Transportation in reverse logistics (RL) plays a significant role and has impact on overall RL performance. Efficiency, effectiveness and impact are the distinct components of RL transportation. Balancing these components requires the implementation of an effective performance measurement (PM) system. The perspectives of balanced scorecard have been used where enterprises can link their performance to their transportation practices, which do

Mohammed N. Shaik; Walid Abdul-Kader

2011-01-01

51

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

SciTech Connect

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

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

2007-02-15

52

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

53

Electrical transport measurements of individual bismuth nanowires and carbon nanotubes  

NASA Astrophysics Data System (ADS)

Nanostructures are defined by reducing dimensions. When the reduced size of materials is comparable to the Fermi wavelength, quantum size effect occurs. Dimensionality plays a critical role in determining the electronic properties of materials, because the density of states of materials is quite different. Nanowires have attracted much attention recently due to their fundamental interest and potential applications. A number of materials have been tried. Among them, bismuth has unique properties. Bismuth has the smallest effective mass as small as 0.001me. This small effective mass of Bi nanowires allows one to observe the quantum confinement effect easily. Also Bi nanowires are good candidates for a low-dimensional transport study due to long mean free path. Because of these remarkable properties of Bi nanowires, many efforts have been made to study Bi nanowires. However, because bismuth is extremely sensitive to the oxide, it is very difficult to make a reliable device. So far, array measurements of Bi nanowires have been reported. The study is focused on the synthesis and electric transport measurements of individual Bi nanowires. Bi nanowires are synthesized by electrodeposition using either anodic aluminum oxide (AAO) templates or commercially available track etched polycarbonate membranes (PCTE). The desired nanowire has a heterostructure of Au - Bi - Au. Au wires on both sides serve as contact electrodes with Bi. To extract nanowires from PCTE or AAO, several attempts have been made. Devices consisting of single Bi nanowires grown by hydrothermal method are fabricated and electrical measurements have been carried out after in-situ deposition of Pt electrodes. The temperature dependence of resistance of majority of nanowires increases with decreasing temperature, showing polycrystalline nature of nanowires. However, some nanowires show resistance peaks at low temperature, suggesting quantum size effect (QSE). Magnetoresistance (MR) has also been measured. We have also studied electric transport measurements of carbon nanotubes grown in AAO templates. These vertically grown carbon nanotubes (CNTs) are useful for field emission device. In addition, ultra-density vertical CNT transistor arrays have also been proposed based on these nanotube structures. To realize these interesting electronic applications, a detailed understanding of the electronic transport properties of the nanotubes is needed. In particular, nanotubes grown in the AAO templates are known to possess significant amount of structural disorder. It is thus important to elucidate the effect of disorder on the electronic properties of these nanotubes. Electrical transport measurements of individual carbon nanotubes are studied, The four-terminal resistance at room temperature scales linearly with the nanotube length indicating diffusive nature of transport. The conductance shows an exp[(-1/T)1/3] dependence on temperature T, suggesting that two-dimensional variable-range hopping is the dominant conduction mechanism. The maximum current density carried by these nanotubes is on the order of 106 A/cm 2.

Jang, Wan Young

54

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

55

Adaptive Quantum Nondemolition Measurement of a Photon Number  

NASA Astrophysics Data System (ADS)

In many quantum measurements, information is acquired incrementally by the successive interaction of meters with the measured system. Adaptive measurements minimize the use of resources (meters) by adjusting the measurement settings according to available information. We demonstrate an adaptive measurement for nondestructive photon counting in a cavity, based on Ramsey interferometry for Rydberg atoms interacting with the field. Tuning the interferometer in real time, we speed up the measurement by up to 45%. Such adaptive methods are promising for quantum metrology, state preparation, and feedback.

Peaudecerf, B.; Rybarczyk, T.; Gerlich, S.; Gleyzes, S.; Raimond, J. M.; Haroche, S.; Dotsenko, I.; Brune, M.

2014-02-01

56

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

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

57

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

SciTech Connect

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

Lynn Lowry; Beverly Tai

1995-03-01

58

Estimate of the number of urea transport sites in erythrocyte ghosts using a hydrophobic mercurial  

Microsoft Academic Search

In this paper a variety of mercurials, including a pCMB-nitroxide analogue, were used to study urea transport in human red cell ghosts. It was determined that the rate of inhibition for pCMBS, pCMB, pCMB-nitroxide, and chlormerodrin extended over four orders of magnitude consistent with their measured oil\\/water partition coefficients. From these results, we concluded that a significant hydrophobic barrier limits

Lidia M. Mannuzzu; Mario M. Moronne; Robert I. Macey

1993-01-01

59

NON-INTRUSIVE MASS FLOW MEASUREMENTS IN PNEUMATIC TRANSPORT  

Microsoft Academic Search

On-line measurements in pneumatic transport systems are a complex task. Several techniques are available for measuring different kinds of flow, however, only some of them are suitable for gas\\/solid systems. This paper describes major techniques used nowadays: capacitive, ultrasonic and microwave. Descriptions of the measuring principle of each technique as well as an overview of the research work reported in

C. Arakaki; A. Ghaderi; B. K. Datta; B. Lie

2006-01-01

60

THE MAHLER MEASURE OF ALGEBRAIC NUMBERS: CHRIS SMYTH  

E-print Network

, house of algebraic integer . 322 #12;Chris Smyth 323 the Mahler measure of the minimal polynomial P. Re- lated results on the maximum modulus of the conjugates (`house') of an algebraic integer are also

Smyth, Chris

61

Measuring the number of lamellar body particles in amniotic fluid.  

PubMed

We describe a method for determining the number and size distribution of lamellar bodies and compare the results prospectively with other tests for fetal lung maturity: lecithin-sphingomyelin ratio (L/S), phosphatidylglycerol, and fluorescence polarization. The technique uses an electronic particle counter calibrated for a size range of 1.7-7.3 fL. The number of lamellar bodies in amniotic fluid samples varied from 3800-166,000 particles per microliter and correlated strongly with L/S ratio (r = 0.75; N = 144) and fluorescence polarization (r = -0.78; N = 165). Amniotic fluid samples stored for up to 10 days at 4C had stable lamellar body counts (within +/- 11%). Longer storage tended to decrease the counts. Addition of more than 1% (v/v) whole blood significantly decreased the lamellar body counts. This technique shows promise for the rapid assessment of fetal lung maturity. PMID:2300359

Ashwood, E R; Oldroyd, R G; Palmer, S E

1990-02-01

62

Monitoring quantum transport: Backaction and measurement correlations  

NASA Astrophysics Data System (ADS)

We investigate a tunnel contact coupled to a double quantum dot (DQD) and employed as a charge monitor for the latter. We consider both the classical limit and the quantum regime. In the classical case, we derive measurement correlations from conditional probabilities, yielding quantitative statements about the parameter regime in which the detection scheme works well. Moreover, we demonstrate that not only the DQD occupation but also the corresponding current may strongly correlate with the detector current. The quantum-mechanical solution, obtained with a Bloch-Redfield master equation, shows that the backaction of the measurement tends to localize the DQD electrons, and thus significantly reduces the DQD current. Moreover, it provides the effective parameters of the classical treatment. It turns out that already the classical description is adequate for most operating regimes.

Hussein, Robert; Gómez-García, Jorge; Kohler, Sigmund

2014-10-01

63

A rain splash transport equation assimilating field and laboratory measurements  

NASA Astrophysics Data System (ADS)

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

Dunne, Thomas; Malmon, Daniel V.; Mudd, Simon M.

2010-03-01

64

Measurement of magnetic fluctuation induced energy transport  

SciTech Connect

The local electron energy flux produced by magnetic fluctuations has been measured directly in the MST reversed field pinch (over the radial range r/a > 0.75). The flux, produced by electrons traveling parallel to a fluctuating magnetic field, is obtained from correlation between the fluctuations in the parallel heat flux and the radial magnetic field. The fluctuation induced flux is large (100 kW/cm{sup 2}) in the ``core`` (r/a < 0.85) and small (< 10--30 kW/cm{sup 2}) in the edge.

Fiksel, G.; Prager, S.C.; Shen, W.; Stoneking, M.

1993-11-01

65

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

Code of Federal Regulations, 2011 CFR

...from temporal transportation control measures for CFFVs. 88.307-94...from temporal transportation control measures for CFFVs. (a) States...304-94(c) from transportation control measures (TCMs) existing...

2011-07-01

66

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

Code of Federal Regulations, 2013 CFR

...from temporal transportation control measures for CFFVs. 88.307-94...from temporal transportation control measures for CFFVs. (a) States...304-94(c) from transportation control measures (TCMs) existing...

2013-07-01

67

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

...from temporal transportation control measures for CFFVs. 88.307-94...from temporal transportation control measures for CFFVs. (a) States...304-94(c) from transportation control measures (TCMs) existing...

2014-07-01

68

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

Code of Federal Regulations, 2012 CFR

...from temporal transportation control measures for CFFVs. 88.307-94...from temporal transportation control measures for CFFVs. (a) States...304-94(c) from transportation control measures (TCMs) existing...

2012-07-01

69

Gasificaton Transport: A Multiphase CFD Approach & Measurements  

SciTech Connect

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

Dimitri Gidaspow; Veeraya Jiradilok; Mayank Kashyap; Benjapon Chalermsinsuwan

2009-02-14

70

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

71

Measured Energy Transport in the MST Reversed-Field Pinch  

NASA Astrophysics Data System (ADS)

Profile measurements in standard and improved confinement (Pulsed Poloidal Current Drive) plasmas have been made in the MST using recently installed or upgraded diagnostics. Estimates of electron thermal diffusivities based upon a diagonal transport relationship indicate a 5 fold reduction in core transport during PPCD. New profile information has been obtained from the following diagnostics: Te from Thomson scattering, majority Ti from Rutherford scattering, ne and nH from coupled FIR interferometry and H_? arrays. Using equilibrium reconstructions, profiles are mapped onto magnetic flux coordinates, and thermodynamic fluxes (?, q) and forces (nablan, nablaT) are estimated for energy and particle transport. Profile measurements are compared with theoretical models based on magnetic field stochasticity (such as those of Rechester-Rosenbluth and Harvey.)

Biewer, T. M.; Anderson, J. K.; Chapman, B. E.; Reardon, J. C.; den Hartog, D. J.; Fiksel, G.; Prager, S. C.; Forest, C. B.; Terry, S. D.; Lanier, N. E.

2000-10-01

72

Prandtl-number Dependence of Heat Transport in Turbulent Rayleigh-Bénard Convection  

NASA Astrophysics Data System (ADS)

We present measurements of the Nusselt number \\cal N as a function of the Rayleigh number R and the Prandtl number ? in cylindrical cells with aspect ratios ? ? D/d = 3.0, 2.0,1.0, and 0.5 (D is the diameter and d the height). We used acetone, methanol, ethanol, and 2-propanol with Prandtl numbers ? = 4.0, 6.5, 14.2, and 34.1 respectively for 10^6 alt R alt 3 × 10^10. At constant R we find that \\cal N(R,?) changes with ? by no more than two percent. The results disagree with the prediction(B. Castaing et al., J. Fluid Mech. 204), 1 (1989); B.I. Shraiman and E.D. Siggia, Phys. Rev. A 42, 3650 (1990) \\cal N = a ?-1/7 R^2/7 which yields a decrease of \\cal N at constant R by 26% over our range of ?. They also disagree with the prediction \\cal N = a ?-1/12 R^1/4 + b ?-1/7 R^3/7 of Grossmann and Lohse(S. Grossmann and D. Lohse, J. Fluid Mech. 407), 27 (2000) for ? agt 2, which, at constant R, implies a decrease by 20% over our ?-range.

Ahlers, Guenter; Xu, Xiaochao

2000-11-01

73

Measurement of the radiative transport properties of reticulated alumina foams  

SciTech Connect

This paper presents a method for determining radiative transport properties of reticulated materials. The method has both experimental and analytical components. A polar nephelometer is used to measure the scattering profile of a sample of the reticulated material. The results of a Monte Carlo simulation of the experiment are then combined with the experimental results to give the scatter albedo and extinction coefficient. This paper presents the results of using this method to determine the radiative transport properties of four different porosities (10, 20, 30, 65 pores per inch) of cylindrical reticulated alumina samples ranging in thickness form 0.5 inches to 2. 5 inches.

Hale, M.J.; Bohn, M.S.

1992-12-01

74

Neutron spectroscopy measurements of tritium beam transport at JET  

NASA Astrophysics Data System (ADS)

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

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

2014-10-01

75

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

76

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

2011-10-10

77

Capacitance-Voltage Measurement of Transporting Function at Cell Membrane  

NASA Astrophysics Data System (ADS)

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

Sakata, Toshiya; Miyahara, Yuji

78

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

Code of Federal Regulations, 2013 CFR

...Contracts and Property Management Federal Property Management Regulations System (Continued) FEDERAL MANAGEMENT REGULATION TRANSPORTATION 117-TRANSPORTATION MANAGEMENT Performance Measures § 102-117.270 What are agency...

2013-07-01

79

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

Code of Federal Regulations, 2011 CFR

...Contracts and Property Management Federal Property Management Regulations System (Continued) FEDERAL MANAGEMENT REGULATION TRANSPORTATION 117-TRANSPORTATION MANAGEMENT Performance Measures § 102-117.270 What are agency...

2011-01-01

80

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

Code of Federal Regulations, 2012 CFR

...Contracts and Property Management Federal Property Management Regulations System (Continued) FEDERAL MANAGEMENT REGULATION TRANSPORTATION 117-TRANSPORTATION MANAGEMENT Performance Measures § 102-117.270 What are agency...

2012-01-01

81

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

82

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

ERIC Educational Resources Information Center

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

Pickard, Poppy; Alexander, Patricia

83

Review on measurement techniques of transport properties of nanowires  

NASA Astrophysics Data System (ADS)

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

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

2013-11-01

84

Review on measurement techniques of transport properties of nanowires.  

PubMed

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

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

2013-12-01

85

Measurement of the change in the number of ultrafine bubbles through pressurization  

NASA Astrophysics Data System (ADS)

The present study deals with, for the first time, a measurement of the number of bubbles of submicron in size before and after pressurization. Measurement of ultrafine bubbles of submicron size was conducted and it was clarified that greater number of submicron sized bubbles existed before the pressurization in comparison with that after the pressurization. The application of high pressure of gas for its dissolution into water and the ambient-pressure reduction has a possibility to increase the number of ultrafine bubbles.

Tuziuti, T.; Yasui, K.; Kanematsu, Wataru

2014-08-01

86

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

Microsoft Academic Search

The objective of this study was to determine if platelet 5-HT transporter (5-HTT) sites vary as a function of aggression, and\\/or impulsiveness, and differ as a function of Intermittent Explosive Disorder (IED). Accordingly, the number of platelet 5-HTT sites was assessed in 100 personality disordered (PD) individuals with varying degrees of aggressiveness. The number of platelet 5-HTT sites was assessed

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

2010-01-01

87

Volume 16I, number I CHEMICAL PHYSICS LETTERS 1SeDtember 1989 DISPERSIVE ELECTRONIC EXCITATION TRANSPORT IN POLYMERIC SOLIDS  

E-print Network

Volume 16I, number I CHEMICAL PHYSICS LETTERS 1SeDtember 1989 DISPERSIVE ELECTRONIC EXCITATION TRANSPORT IN POLYMERIC SOLIDS AT AND NEAR ROOM TEMPERATURE Alan D. STEIN, Kristen A. PETERSON ' and M in a polymeric solid as a function of excitation wavelength between 300 and 50 K. The characteristicsofthe

Fayer, Michael D.

88

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

89

Measuring hot plasma transport coefficients with stripped cluster galaxies  

NASA Astrophysics Data System (ADS)

Cluster galaxies are gas-stripped during their motion through the cluster gas. Thermal conductivity and viscosity of the hot gas -or plasma- in and around these galaxies affect the stripping mechanisms, and in particular the multiphase nature of the tails of stripped gas and star formation in tails of the spirals. However, the effective transport coefficients are still ill-constrained. Current deep X-ray observations of stripped nearby cluster ellipticals show the details of the plasma flows around them. We aim at measuring the effective plasma transport coefficients by means of one-to-one comparisons to viscous hydro-simulations tailored to each galaxy. We report first evidence for a highly suppressed viscosity around Virgo and Fornax cluster ellipticals and discuss future observations.

Roediger, Elke

2014-08-01

90

Low Reynolds number scalar transport enhancement in viscous and non-Newtonian fluids  

Microsoft Academic Search

Enhancement of heat and\\/or mass transfer via turbulence is often not feasible for highly viscous, non-Newtonian or shear sensitive fluids. One alternative to improve transport within such materials is chaotic advection, whereby Lagrangian chaos occurs within regular (non-turbulent) flows [J.M. Ottino, The Kinematics of Mixing: Stretching, Chaos and Transport, Cambridge University Press, Cambridge, 1989]. Complex interactions between chaotic advection and

D. R. Lester; M. Rudman; G. Metcalfe

2009-01-01

91

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

E-print Network

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

Zare, Richard N.

92

Measuring Relative Atom Number Fluctuations in Coherently Split Quantum Degenerate Gases  

NASA Astrophysics Data System (ADS)

We report on direct measurements of atom number fluctuations in a double-well Bose Einstein condensate (BEC) system. A single BEC is dynamically and coherently split into two halves -- left (L) and right (R). This is accomplished by deforming a single 3-dimensional harmonic magnetic trap into a double-well trap by combining static and time-varying radio-frequency magnetic fields on an atom chip. Fluctuations in the relative atom number Nr = NR - NL in repeated trials are evaluated against the shot-noise preduction of binomial statistics. We determine the atom number statistics of the splitting process by directly measuring the atom numbers in the left and right wells after splitting, and the fluctuations in the relative atom number in successive repetitions of the experiment using time-of-flight absorption imaging. We will discuss possible extensions of this method to measurements of splitting statistics using a degenerate Fermi gas.

Extavour, Marcius H. T.; McKeever, Jason; Leblanc, Lindsay J.; Jervis, Dylan; Stummer, Alan; Schumm, Thorsten; Thywissen, Joseph H.

2008-05-01

93

Measurements of thermal transport in low stress silicon nitride films  

NASA Astrophysics Data System (ADS)

We have measured the thermal conductance, G, of ?1 ?m thick low stress silicon nitride membranes over the temperature range, 0.064 K, G is independent of surface condition indicating that the thermal transport is determined by bulk scattering. For T<4 K, scattering from membrane surfaces becomes significant. Membranes which have submicron sized Ag particles glued to the surface or are micromachined into narrow strips have a G that is reduced by a factor as large as 5 compared with that of clean, solid membranes with the same ratio of cross section to length.

Holmes, W.; Gildemeister, J. M.; Richards, P. L.; Kotsubo, V.

1998-05-01

94

Measuring Trans-Atlantic aerosol transport from Africa  

NASA Astrophysics Data System (ADS)

An estimated three billion metric tons of mineral aerosols are injected into the troposphere annually from the Saharan desert [Prospero et al., 1996]. Additionally, smoke from biomass burning sites in the savanna grasslands in sub-Saharan Africa contribute significant quantities of smaller-sized aerosols [e.g., Hobbs, 2000]. These windswept aerosols from the African continent are responsible for a variety of climate, health, and environmental impacts on both global and regional scales that span the Western Hemisphere. Unfortunately in situ measurements of aerosol evolution and transport across the Atlantic are difficult to obtain, and satellite remote sensing of aerosols can be challenging.

Morris, Vernon; Clemente-Colón, Pablo; Nalli, Nicholas R.; Joseph, Everette; Armstrong, Roy A.; Detrés, Yasmin; Goldberg, Mitchell D.; Minnett, Peter J.; Lumpkin, Rick

2006-12-01

95

Direct Schmidt number measurement of high-gain parametric down conversion  

E-print Network

In this work we estimate the transverse Schmidt number for the bipartite bright squeezed vacuum state by means of second-order intensity correlation function measurement. Assuming that the number of modes is equal in both beams we determine the Schmidt number considering only one of the subsystems. The obtained results demonstrate that this approach is equally efficient over the whole propagation of the state from the near field to the far field regions of its emitter.

I. V. Dyakonov; P. R. Sharapova; T. Sh. Iskhakov; G. Leuchs

2014-05-23

96

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

NASA Technical Reports Server (NTRS)

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

Herring, G. C.

2008-01-01

97

Field measurements of tracer gas transport by barometric pumping  

SciTech Connect

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

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

1994-07-28

98

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

99

Measuring transport AC losses in YBCO-coated conductor coils  

NASA Astrophysics Data System (ADS)

Several AC power applications of YBCO-coated conductors (CCs) involve superconducting tapes wound in coils. In such a configuration the superconducting tape is arranged as closely packed turns, which strongly interact due to the generated magnetic field. This has a strong influence on the AC losses, which are different from those of an isolated tape, and need to be precisely quantified in order to predict and reduce the refrigeration requirements of applications. In this paper we experimentally evaluate the transport AC losses in a pancake coil composed of 25 turns of superconducting tape. We describe in detail the measuring technique utilized, pointing out the issues in this kind of measurement. We also present preliminary results of AC loss computation by finite-element modelling.

Grilli, F.; Ashworth, Stephen P.

2007-08-01

100

Direct Measurement of Impurity Transport in a Field Reversed Configuration  

NASA Astrophysics Data System (ADS)

An optical tomography system has been developed and implemented in the Flux Coil Generated Field Reversed Configuration (FCG-FRC) at Tri Alpha Energy. Sixteen chords view ˜35% of the FRC at the mid-plane. The chords are arranged in two identical fans of eight chords each. To measure transport of an impurity species, argon, an FRC is generated using either Nitrogen or Deuterium as the primary species. A puff valve is activated prior to the shot such that the argon begins to bleed in to the vacuum chamber as the FRC is formed. The gas is puffed at the optimal location for tomographic reconstruction. Each chord is collimated to illuminate a fiber optic cable which is fed to an array of photomultiplier tubes which are fitted with neutral density and band pass filters to allow the appropriate amount of light from the emitting, singly ionized, argon at 434.8 nm to be measured. Using a preliminary assumption that density of argon is proportional to light intensity gathered data have been used to reconstruct density profiles. These profiles often peak near the field null. The data are being analyzed to determine diffusive and convective transport coefficients.

Roche, T.; Bolte, N.; Heidbrink, W. W.; McWilliams, R.; Wessel, F.

2011-11-01

101

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

NASA Astrophysics Data System (ADS)

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

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

2012-01-01

102

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

PubMed

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

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

2012-01-30

103

Bidirectional transepithelial water transport: measurement and governing mechanisms.  

PubMed Central

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

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

1999-01-01

104

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

NASA Astrophysics Data System (ADS)

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

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

2012-04-01

105

Progress with Molecular Mixing Measurements & High Atwood Number Experiments at Texas A&M University  

NASA Astrophysics Data System (ADS)

Current progress with high Schmidt number molecular mixing measurements in a small Atwood number water channel facility is reported. In the experiments, the pH of the heavy (salt) and light (fresh) water streams is controlled by adding acid or alkali to each stream. As the two streams molecularly mix, the chemical reaction between the acid and alkali is marked by a phenolphthalein chemical indicator, which is imaged under backlit conditions. The current high Schmidt number (˜700) experiments have resulted in low measures of molecular mixing as compared with previous experiments and simulations at moderate Schmidt numbers. In addition, progress with measurements at high Atwood numbers (˜0.6) in a gas channel facility using helium and air is also reported. Instantaneous velocity and density measurements inside the mixing layer are obtained using a novel combined hot-wire / cold-wire anemometry technique, where temperature is used as a fluid marker. This technique provides detailed simultaneous velocity and density measurements which allows for determination of velocity and density variances, velocity-density cross-correlations, and their spectra.

Andrews, Malcolm J.; Kraft, Wayne N.; Mueschke, Nicholas J.

2007-11-01

106

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

NASA Technical Reports Server (NTRS)

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

Cole, Gregory M.; Mueller, Thomas J.

1990-01-01

107

Measurements of thermal transport in low stress silicon nitride films  

SciTech Connect

We have measured the thermal conductance, G, of {approx}1 {mu}m thick low stress silicon nitride membranes over the temperature range, 0.06{lt}T{lt}6 K, as a function of surface condition. For T{gt}4 K, G is independent of surface condition indicating that the thermal transport is determined by bulk scattering. For T{lt}4 K, scattering from membrane surfaces becomes significant. Membranes which have submicron sized Ag particles glued to the surface or are micromachined into narrow strips have a G that is reduced by a factor as large as 5 compared with that of clean, solid membranes with the same ratio of cross section to length. {copyright} {ital 1998 American Institute of Physics.}

Holmes, W.; Gildemeister, J.M.; Richards, P.L. [Physics Department, University of California, Berkeley, California94720 (United States)] [Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California94720 (United States)] [Physics Department, University of California, Berkeley, California94720 (United States); Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California94720 (United States); Kotsubo, V. [Conductus, Inc., Sunnyvale, California94440 (United States)] [Conductus, Inc., Sunnyvale, California94440 (United States)

1998-05-01

108

The Evaluation Measure of Text Clustering for the Variable Number of Clusters  

Microsoft Academic Search

This study proposes an innovative measure for evaluating the performance of text clustering. In using K-means algorithm and\\u000a Kohonen Networks for text clustering, the number clusters is fixed initially by configuring it as their parameter, while in\\u000a using single pass algorithm for text clustering, the number of clusters is not predictable. Using labeled documents, the result\\u000a of text clustering using

Taeho Jo; Malrey Lee

2007-01-01

109

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

110

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

NASA Technical Reports Server (NTRS)

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

Jovic, Srba; Driver, David M.

1994-01-01

111

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

SciTech Connect

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

Bianchi, J.C.

1993-03-01

112

Direct Measurements of Eddy Transport and Thermal Dispersion in a High Porosity Matrix  

NASA Technical Reports Server (NTRS)

Thermal losses from the hot end to the cold end of a Stirling cycle regenerator due to thermal dispersion through the regenerator matrix may significantly degrade the performance of the machine. Because of poor access to the void spaces within the porous medium, no direct measurements of thermal dispersion have been made and dispersion models have been derived indirectly. This is done by measuring the overall thermal performance of the regenerator and subtracting off the energy transfer caused by molecular conduction and advected enthalpy flows computed from volume-averaged fluid velocity and temperature. In the current program, a large-scale porous matrix consisting of stacked wire screens with a porosity of 90% is installed in a flow rig which is operated in a Reynolds number range that represents Stirling engine regenerator flow. Experiments are conducted to measure turbulent transport of momentum at the exit phase using hot-wires. The relationship of such turbulent transport terms to the thermal dispersion term in the volumetric-averaged energy equation for the regenerator matrix is developed and the measurements are used to determine cross-stream thermal dispersion. A dispersion model based upon the measurements is proposed and compared with models documented in the literature.

Niu, Yi; Simon, David; Gedeon, David

2004-01-01

113

Measurements of Sediment Transport in the Western Adriatic Sea  

NASA Astrophysics Data System (ADS)

Instrumented bottom tripods were deployed at two depths (10 and 20 m) off the mouth of the Chienti River in the western Adriatic Sea from November 2002 to May 2003 as part of the EuroSTRATAFORM Po and Apennine Sediment Transport and Accumulation (PASTA) Experiment. Waves, currents, and proxies for suspended-sediment concentrations were measured with upward-looking acoustic Doppler current meters, downward looking pulse-coherent acoustic Doppler profilers, single-point acoustic Doppler velocimeters, and acoustic and optical backscatter sensors. Flow was dominated by the western Adriatic coastal current (WACC) during the experiment. Mean southward alongshore velocity 2 m below the surface was 0.10 m/s at the 10-m site and 0.23 m/s at the 20-m site, and flow was modulated by tides, winds, and fluctuating riverflow. The largest waves (3 m significant height) were generated by winds from the southeast during a Sirocco event in late November that generated one of the few episodes of sustained northward flow and sediment transport. Most of the time, however, sediment resuspension and transport was dominated by Bora events, when downwelling-favorable winds from the northeast generated waves that resuspended sediment and simultaneously enhanced southward flow in the WACC. Mean flow near the bottom was slightly offshore at the 20-m site (0.01 m/s at 3 m above the bottom), but there was no significant correlation between downwelling and wave-induced resuspension, and cross-shelf sediment fluxes were small. The combination of persistent southward flow with low rates of cross-shelf leakage makes the WACC an efficient conduit for sediment past the Chienti region. If these observations are representative of typical winter conditions along the entire western Adriatic, they may help explain the enigmatic development of Holocene shelf-edge clinoforms that have formed hundreds of kilometers south of the Po River, which provides most of the sediment to the Adriatic Sea. Future data analysis and modeling is planned to investigate the mechanism(s) that apparently limit(s) sediment leakage from the WACC.

Sherwood, C. R.; Hill, P. S.

2003-12-01

114

Chemical data assimilation of Transport and Chemical Evolution over the Pacific (TRACE-P) aircraft measurements  

NASA Astrophysics Data System (ADS)

In this paper, the four-dimensional variational (4D-Var) technique is applied to assimilate aircraft measurements during the Transport and Chemical Evolution over the Pacific (TRACE-P) field experiment into a chemical transport model, Sulfur Transport Eulerian Model, version 2K1 (STEM-2K1). Whether data assimilation would produce better analyzed fields is examined. It is found that assimilating ozone observations from one of two independent flights improves model prediction of the other flight ozone measurements, which are withheld as validation data. The adjusted initial fields after only assimilating the total reactive nitrogen (NOy) observations lead to better predictions of NO, NO2, and PAN, based on their agreement with the withheld measurements. One experiment simultaneously assimilating the observations of O3, NO, NO2, HNO3, PAN, and RNO3 demonstrates that the model is able to match those measurements well by changing the initial fields. In addition, the model predictions of NOy improve significantly after assimilating the aforementioned multiple observation species, which are independent of the withheld NOy measurements. In the paper, we also show that the key species whose initial mixing ratios would significantly affect the agreement between model and measurements can be identified using adjoint sensitivity analysis. Such information can be used to reduce the number of control variables in the 4D-Var data assimilation. To speed up the optimization process in the 4D-Var, we enforce the concentration upper bounds through the limited memory-Broyden-Fletcher-Goldfarb-Shanno-B (L-BFGS-B) algorithm, and this proves to be effective.

Chai, Tianfeng; Carmichael, Gregory R.; Sandu, Adrian; Tang, Youhua; Daescu, Dacian N.

2006-01-01

115

Measurement of two-mode squeezing with photon number resolving multi-pixel detectors  

E-print Network

The measurement of the two-mode squeezed vacuum generated in an optical parametric amplifier (OPA) was performed with photon number resolving Multi-Pixel Photon Counters (MPPCs). Implementation of the MPPCs allows for the observation of noise reduction in a broad dynamic range of the OPA gain, which is inaccessible with standard single photon avalanche photodetectors.

Dmitry A. Kalashnikov; Si-Hui Tan; Timur Sh. Iskhakov; Maria V. Chekhova; Leonid A. Krivitsky

2012-05-14

116

Non-Intrusive mach number measurement in a supersonic hydrogen fluoride laser  

Microsoft Academic Search

An experimental technique has been developed to directly measure flow velocity and Mach number in a supersonic hydrogen fluoride laser. The technique uses a tunable diode laser source to probe the laser cavity at an angle to the flow creating a Doppler shifted lineshape. The amount of Doppler shift can be related to the flow velocity. The diode laser was

Charles F Wisniewski; Kevin B Hewett; Gerald C Manke II; C Randall Truman; Gordon D Hager

2003-01-01

117

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

PubMed

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

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

2014-10-01

118

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

NASA Astrophysics Data System (ADS)

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

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

2014-10-01

119

Spatial profile measurement of electron number densities and analyte line intensities in an inductively coupled plasma  

NASA Astrophysics Data System (ADS)

A versatile instrument for spatial profile measurement has been developed and applied to the measurement of electron number densities and analyte emission intensities in an inductively coupled plasma (ICP). A precise Y-Z stage on which the ICP source was mounted was set on a rail-based optical bench. By translating the ICP source with a precision of ± 0.01 mm, the H ? Stark broadening and analyte line intensities were measured with the use of a silicon intensified target (SIT) and a photomultiplier (PMT). Micro-computer assisted data acquisition allowed it to measure a large number of emission profiles in a short period. The ease of acquisition enabled to build up complete contour maps of electron number densities, Ca neutral atom (Ca I) and Ca ion (Ca II) line intensities, and intensity ratios of the Ca II and Ca I lines. The maximum electron number density was 4 × 10 15 cm -3 occurring low in the plasma and 5 mm off axis. In a contour map of the electron number densities a hollow region was found low in the plasma, and the distribution pattern looked like a deep "trench". Along the central channel of the ICP, the peak position of Ca II emission occurred higher than that of Ca I emission, and the spatial distribution of Ca II emission was wider and taller than that of Ca I emission. It has been verified that Ca I is emitted mainly at the region where the electron number density is less than 1 × 10 14 cm -3.

Furuta, N.; Nojiri, Y.; Fuwa, K.

120

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

PubMed

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

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

2014-05-01

121

Measuring Quantum Correlations using Lossy Photon-Number-Resolving Detectors with Saturation  

E-print Network

The variance of difference of photocounts is an established measure of quantum correlations for quantum states of light. It enables us to discriminate between the classical correlation of a two-mode coherent state and the quantum correlation of a twin-beam state. We study the effect of loss and saturation of the photon-number-resolving detector on the measurement of the variance of difference of photocounts. An analytic function is derived for this variance, both for the coherent and the twin-beam states. It is found that the variance of difference of photocounts is no longer a reliable entanglement measure in the non-linear regime of the detector response but it remains useful in some range of values of average photon numbers of the incident light. We also quantify the linear regime of the detector with saturation which will be useful for calibration of the detector quantum efficiency.

Si-Hui Tan; Leonid A. Krivitsky; Berthold-Georg Englert

2012-10-30

122

A simple method to measure the thickness and order number of a wave plate  

NASA Astrophysics Data System (ADS)

Thickness and order number are important parameters for a wave plate in optical experiments. However, the encapsulation of the wave plate makes its thickness difficult to measure directly. In this paper, we propose an indirect measurement method to obtain the thickness and order number of a uniaxial crystal wave plate. With this method only the maximum and minimum values of the optical power of the transmitted light through the wave plate are measured in the experiment by rotating the wave plate around its optical axis. This simple method is easy to realize in the college physics laboratory, and it is also of importance for students to further understand the underlying physics of the wave plates.

Hu, Yichuan; Yi, Zhenglei; Yang, Hujiang; Xiao, Jinghua

2013-09-01

123

PERFORMANCE MEASUREMENT OF MONTE CARLO PHOTON TRANSPORT ON PARALLEL MACHINES  

E-print Network

particle transport is an inherently parallel (or embarrassingly parallel) computational method that has there is also interest to explore multithreaded architectures to improve parallel performance of scientific

Majumdar, Amit

124

Thermal Transport Measurements of Low Stress Silicon Nitride Membranes  

NASA Astrophysics Data System (ADS)

We have measured the thermal conductance, G_m, of low stress silicon nitride membranes of thicknesses tm < 1? m at temperatures 0.06 < T < 6K and with variable surface conditions. Since the phonon mean free paths, estimated from Gm and the specific heat are larger than t_m, phonon surface scattering is expected to be important. For T>4K, Gm is independent of surface condition so the thermal transport is determined by bulk diffusion and is consistent with other amorphous materials. For T<4K, we find that Gm is well described by a model that accounts for both surface and bulk scattering. For T<0.2K, for solid membranes with clean surfaces, phonon surface scattering is specular and the theoretical calculation of Gm fits our data with no free parameters. For T<4K, values of Gm for membranes with sub-micron sized Ag particles glued to the surface and membranes micromachined into radial spokes are reduced by factors of up to 5. This work was supported in part by the Director, Office of Energy Research, Office of Basic Energy Sciences, Materials Sciences Division of the U.S. Department of Energy under Contract No. DE-AC03-76SF00098.

Holmes, W.; Gildemeister, J. M.; Richards, P. L.; Kotsubo, V.

1998-03-01

125

A transportable hemispherical illumination system for making reflectance factor measurements  

NASA Technical Reports Server (NTRS)

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

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

1987-01-01

126

Transport and STM measurements of HCI modified materials  

NASA Astrophysics Data System (ADS)

While more than a decade of work has provided glimpses into the physics of highly charged ion (HCI) neutralization on surfaces, two prominent objectives remain unfulfilled: (1) a unified, quantitative model for separating the kinetic energy response of a wide range of materials classes from the effects of HCIs' potential energy effects and (2) insertion of HCI technology(s) as a cost-effective processing tool in a high-volume market sector. The National Institute of Standards and Technology (NIST) electron beam ion trap (EBIT) facility has recently incorporated tools for preparing clean, atomically flat surfaces of single crystals from gold to tungsten to silicon and for depositing and patterning thin films that range from high resistivity oxides to transition metals like cobalt and nickel. Current activities are focused on utilizing this unique capability to simultaneously address both of the objectives above by employing technologically important magnetic multi-layer systems to perform transport measurements that provide new insight into the fundamental processes that occur during HCI-surface neutralization. Specifically, we are producing Magnetic Tunnel Junctions (MTJs) critical to both magnetic devices and incorporating HCIs in the processing recipe to adjust critical electronic properties that are currently inhibiting their advancement. In return, the electrical response of the tunnel junction to the HCI processing provides a novel approach to performing ensemble measurements of HCI-surface interactions. By varying the construction of the tunnel junction, critical tests of the role of electron density, densities of states and electronic structure in the HCI-surface charge exchange can be performed.

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

2007-03-01

127

Detailed noise measurements on the SR-7A propeller: Tone behavior with helical tip Mach number  

NASA Technical Reports Server (NTRS)

Detailed noise measurements were taken on the SR-7A propeller to investigate the behavior of the noise with helical tip Mach number and then to level off as Mach number was increased further. This behavior was further investigated by obtaining detailed pressure-time histories of data. The pressure-time histories indicate that a portion of the primary pressure pulse is progressively cancelled by a secondary pulse which results in the noise leveling off as the helical tip Mach number is increased. This second pulse appears to originate on the same blade as the primary pulse and is in some way connected to the blade itself. This leaves open the possibility of redesigning the blade to improve the cancellation; thereby, the propeller noise is reduced.

Dittmar, James H.; Hall, David G.

1991-01-01

128

Using a qubit to measure photon-number statistics of a driven thermal oscillator  

NASA Astrophysics Data System (ADS)

We demonstrate theoretically how photon-number statistics of a driven damped oscillator at finite temperature can be extracted by measuring the dephasing spectrum of a two-level system dispersively coupled to the oscillator; we thus extend the work of M. I. Dykman and M. A. Krivoglaz [Sov. Phys. Solid State 29, 210 (1987)] and J. Gambetta [Phys. Rev. A 74, 042318 (2006)]. We carefully consider the fidelity of this scheme—to what extent does the measurement reflect the initial number statistics of the mode? We also derive analytic results for the dephasing of a qubit by a driven thermal mode, and compare results obtained at different levels of approximation. Our results have relevance both to experiments in circuit cavity QED, as well as to nanoelectromechanical systems.

Clerk, A. A.; Utami, D. Wahyu

2007-04-01

129

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

Microsoft Academic Search

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

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

2012-01-01

130

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

131

Indicators that matter : measuring transportation performance in Ahmedabad  

E-print Network

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

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

2012-01-01

132

Progress With the Velocity and Density Measurements in High Atwood Number Rayleigh-Taylor Mixing  

NASA Astrophysics Data System (ADS)

A statistically steady gas channel experiment is used to study the non-equilibrium development of high Atwood number Rayleigh-Taylor mixing. Two gas streams, one containing air-helium mixture and the other air, flow parallel to each other separated by a thin splitter plate. The streams meet at the end of a splitter plate leading to the formation of an unstable interface and initiation of buoyancy driven mixing. This set up is statistically steady in space and allows for long data collection times. Here, we describe initial validation work to measure the self similar evolution of mixing at density differences (At ˜ 0.05). In addition we also present velocity and density measurements at density differences of At ˜ 0.25. The facility is being currently used for studying the evolution of the mix at large density differences up to At ˜ 0.75. Diagnostics include a Constant Temperature (CT) as well as a Constant current (CC) Hot Wire anemometer and a high resolution digital image analysis. Analysis of measured data is used to explain the structure of mixing as it develops to a self-similar regime. The purpose of this paper is to describe the progress made in the High Atwood number facility and present the initial validation results as well as density and velocity measurements using the diagnostics described above.

Banerjee, Arindam

2005-11-01

133

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.

134

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

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

135

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

NASA Astrophysics Data System (ADS)

The molecular motor gliding assay, in which a microtubule or other filament moves across a surface coated with motors, has provided much insight into how molecular motors work. The kinesin-microtubule system is also a strong candidate for the job of nanoparticle transporter in nanotechnology devices. In most cases, several motors transport each filament. Each motor serves both to bind the microtubule to a stationary surface and to propel the microtubule along the surface. By applying a uniform transverse force of 4-19 pN to a superparamagnetic bead attached to the trailing end of the microtubule, we have measured the distance d between binding points (motors). The average value of d was determined as a function of motor surface density ?. The measurements agree well with the scaling model of Duke, Holy, and Liebler, which predicts that ~?-2/5 if 0.05???20?m-2 [Phys. Rev. Lett.PRLTAO0031-900710.1103/PhysRevLett.74.330 74, 330 (1995)]. The distribution of d fits an extension of the model. The radius of curvature of a microtubule bent at a binding point by the force of the magnetic bead was ?1 ?m, 5000-fold smaller than the radius of curvature of microtubules subjected only to thermal forces. This is evidence that at these points of high bending stress, generated by the force on the magnetic bead, the microtubule is in the more flexible state of a two-state model of microtubule bending proposed by Heussinger, Schüller, and Frey [Phys. Rev. EPLEEE81063-651X10.1103/PhysRevE.81.021904 81, 021904 (2010)].

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

2011-01-01

136

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

NASA Technical Reports Server (NTRS)

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

Whiteman, D.

1988-01-01

137

Simple and versatile molecular method of copy-number measurement using cloned competitors.  

PubMed

Variations and alterations of copy numbers (CNVs and CNAs) carry disease susceptibility and drug responsiveness implications. Although there are many molecular methods to measure copy numbers, sensitivity, reproducibility, cost, and time issues remain. In the present study, we were able to solve those problems utilizing our modified real competitive PCR method with cloned competitors (mrcPCR). First, the mrcPCR for ERBB2 copy number was established, and the results were comparable to current standard methods but with a shorter assay time and a lower cost. Second, the mrcPCR assays for 24 drug-target genes were established, and the results in a panel of NCI-60 cells were comparable to those from real-time PCR and microarray. Third, the mrcPCR results for FCGR3A and the FCGR3B CNVs were comparable to those by the paralog ratio test (PRT), but without PRT's limitations. These results suggest that mrcPCR is comparable to the currently available standard or the most sensitive methods. In addition, mrcPCR would be invaluable for measurement of CNVs in genes with variants of similar structures, because combination of the other methods is not necessary, along with its other advantages such as short assay time, small sample amount requirement, and applicability to all sequences and genes. PMID:23936009

Kim, Hyun-Kyoung; Hwang, Hai-Li; Park, Seong-Yeol; Lee, Kwang Man; Park, Won Cheol; Kim, Han-Seong; Um, Tae-Hyun; Hong, Young Jun; Lee, Jin Kyung; Joo, Sun-Young; Seoh, Ju-Young; Song, Yeong-Wook; Kim, Soo-Youl; Kim, Yong-Nyun; Hong, Kyeong-Man

2013-01-01

138

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

NASA Technical Reports Server (NTRS)

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

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

2001-01-01

139

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

140

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

NASA Astrophysics Data System (ADS)

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

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

2009-02-01

141

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

NASA Astrophysics Data System (ADS)

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

Beylich, Achim A.; Laute, Katja

2014-08-01

142

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

E-print Network

Reversing the weak measurement of an arbitrary field with finite photon number Qingqing Sun,1,* M. Al-Amri,2 and M. Suhail Zubairy1 1Department of Physics and Institute of Quantum Studies, Texas A&M University, College Station, Texas 77843, USA 2...; Level structure in step #1;II#2;. The classical field is #16;? polarized. #1;c#2; The profiles of the fields required for the adiabatic passages. #1;d#2; The system diagram. SUN, AL-AMRI, AND ZUBAIRY PHYSICAL REVIEW A 80, 033838 #1;2009#2; 033838...

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

2009-01-01

143

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

NASA Astrophysics Data System (ADS)

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

Sakurai, Hiromu; Ehara, Kensei

2011-02-01

144

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

NASA Technical Reports Server (NTRS)

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

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

1972-01-01

145

TRANSPORTATION-RELATED VOLATILE HYDROCARBON SOURCE PROFILES MEASURED IN ATLANTA  

EPA Science Inventory

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

146

MOBILITY MEASUREMENT IN URBAN TRANSPORTATION (MMUT) RESEARCH PROJECT  

E-print Network

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

147

Measure of Diffusion Model Error for Thermal Radiation Transport  

E-print Network

of the diffusion model error called the diffusion model error source (DME source). When this DME source is added to the diffusion equation, the transport solution for the angular-integrated intensity is obtained. In contrast to the variable-Eddington tensor, our...

Kumar, Akansha

2013-04-19

148

Well Measured Developing Indicators for Comprehensive and Sustainable Transport Planning  

Microsoft Academic Search

This paper provides guidance on the selection of indicators for comprehensive and sustainable transportation planning. It discusses the concept of sustainability and the role of indicators in planning, describes factors to consider when selecting indicators, identifies potential problems with conventional indicators, describes examples of indicators and indicator sets, and provides recommendations for selecting indicators for use in a particular situation.

Todd Litman

2005-01-01

149

Time-dependent measurements over membrane plates at low Reynolds number  

NASA Astrophysics Data System (ADS)

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

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

2010-11-01

150

Field wind erosion measurements with Big Spring Number Eight (BSNE) and Modified Wilson and Cook (MWAC) samplers  

NASA Astrophysics Data System (ADS)

The aim of this study was to compare the horizontal mass flux (HMF) of Aeolian sediment obtained from field wind erosion measurements with the Modified Wilson and Cook (MWAC) and Big Spring Number Eight (BSNE) and to analyze the effectiveness of exponential, power, logarithmic and rational equations to calculate the horizontal mass transport (HMT) for each sampler type. With this purpose wind erosion was measured on fine sandy loam soil in 10 erosion events between December 4, 2008 and July 1, 2009. The relative efficiency of the MWAC related to BSNE (RE W/B, quotient between the HMF of MWAC and the HMF of BSNE multiplied by 100) was 247% while RE W/B obtained from the absolute efficiency of the BSNE (85% to 95%) and MWAC (44% to 120%) found in previous studies, was between 51% and 141%. The RE W/B increased with height, as a consequence of the wind speed increase and particle size decrease, which reduces the efficiency of the BSNE while the efficiency of the MWAC remains constant. Depending on the equation used, the HMT of MWAC was from 2.1 to 2.53 times higher than the HMT of BSNE indicating that if the HMF is corrected by the RE W/B, found in this study, the HMT obtained with the MWAC and BSNE is similar. The HMT obtained from exponential equations was 16% higher than the power equation and, 62% and 11% lower than logarithmic and rational equations respectively. In spite of this, the HMT obtained with different equations presented a good relationship with each other (p < 0.05), indicating that the HMT can be corrected and compared between equations. This study shows that the HMF and HMT data obtained from field measurements with the BSNE and MWAC are different. Nevertheless, comparable measurements of wind erosion can be obtained with both samplers taking into account the relative efficiency and the relationship between equations found in this study.

Mendez, Mariano J.; Funk, Roger; Buschiazzo, Daniel E.

2011-06-01

151

Evolution of particle number distribution near roadways— Part I: analysis of aerosol dynamics and its implications for engine emission measurement  

Microsoft Academic Search

Abstract Studies have suggested,that aerosol number,concentrations,maybe,better correlated to health effects than mass concentrations,so that the high particle number,concentrations,in the vicinityof freeway s raise concerns,regarding adverse health effects on people living there. Thus, it is important to understand how particles transport and transform near roadways for regulatory purposes. Driven by different mixing forces, exhaust dilution near roadways usually experiences two,distinct dilution

K. Max Zhang; Anthonys. Wexler

152

Measurement and modeling of phosphorous transport in shallow groundwater environments  

NASA Astrophysics Data System (ADS)

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

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

2014-08-01

153

Measured transonic unsteady pressures on an energy efficient transport wing with oscillating control surfaces  

NASA Technical Reports Server (NTRS)

Highlight results are presented from subsonic and transonic pressure measurement studies conducted in the Langley Transonic Dynamics Tunnel on a supercritical wing model representative of an energy efficient transport design. Steady- and unsteady-pressure data were acquired on the upper and lower wing surface at an off-design Mach number of 0.60 and at the design Mach number of 0.78, for a Reynolds number of 2.2 x 10(6) (based on the wing average chord). The model configuration consisted of a sidewall-Mounted half-body fuselage and a semi-span wing with an aspect ratio of 10.76, a leading-edge sweepback angle of 28.8 degrees, and supercritical airfoil sections. The wing is instrumented with 252 static pressure orifices and 164 dynamic pressure gages. Model test variables included wing angle of attack, control-surface mean deflection angle, control-surface oscillating deflection angle and frequency, and phasing between oscillating leading-edge and trailing-edge controls when used together.

Cazier, F. W., Jr.; Watson, J. J.; Doggett, R. V., Jr.; Sandford, M. C.; Ricketts, R. H.

1981-01-01

154

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

NASA Technical Reports Server (NTRS)

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

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

2000-01-01

155

Measurement of phloem transport rates by an indicator-dilution technique. [Triticum aestivum L  

SciTech Connect

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 {sup 32}PO{sub 4} transport in pulse-labeling experiments. Specific activities (i.e. {sup 32}P 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 CO{sub 2} 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 wheat peduncle and should be useful for other systems as well.

Fisher, D.B. (Washington State Univ., Pullman (USA))

1990-10-01

156

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

157

Fluorescent contacts measure the coordination number and entropy of a 3D jammed emulsion packing  

E-print Network

Jammed matter is by definition impenetrable to light, rendering the characterization of the 3D geometry difficult. Confocal microscopy of a dyed, refractive index matched emulsion nevertheless allows one to image the jammed system. Here we explain the origin of the mechanism of enhanced fluorescence at the contacts of jammed emulsion droplets in terms of a blue-shifted fluorescence emission band due to the change in the polarity of the interfacial environment. We then use this information to determine the contact network in the emulsion, which models a frictionless jammed system. This enables the experimental determination of the average coordination number, $$ giving the theoretically predicted value of $ \\approx 6$. Furthermore, the method enables the experimental measurement of the entropy of the packing from the network of contacts.

J. Brujic; G. Marty; C. Song; C. Briscoe; H. A. Makse

2006-05-31

158

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

SciTech Connect

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

Malcolm J. Andrews, Ph.D.

2004-12-14

159

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

2012-11-01

160

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

NASA Astrophysics Data System (ADS)

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

Nazé, Pierre; Venegeroles, Roberto

2014-10-01

161

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

NASA Astrophysics Data System (ADS)

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

Kore, Prashant S.; Pawar, Pravina P.

2014-05-01

162

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

PubMed

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

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

2011-04-11

163

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

Microsoft Academic Search

Numerical simulation on the Air Data Sensor System (ADS), which measures the flow angles and Mach number using the surface pressures on a nose cone, was conducted in this study. The effect of the half cone angle on the flow angle and Mach number measurement was investigated. As a result, we found that a large half cone angle achieves a

2010-01-01

164

Molybdate transport in a chemically complex aquifer: Field measurements compared with solute-transport model predictions  

USGS Publications Warehouse

A natural-gradient tracer test was conducted in an unconfined sand and gravel aquifer on Cape Cod, Massachusetts. Molybdate was included in the injectate to study the effects of variable groundwater chemistry on its aqueous distribution and to evaluate the reliability of laboratory experiments for identifying and quantifying reactions that control the transport of reactive solutes in groundwater. Transport of molybdate in this aquifer was controlled by adsorption. The amount adsorbed varied with aqueous chemistry that changed with depth as freshwater recharge mixed with a plume of sewage-contaminated groundwater. Molybdate adsorption was strongest near the water table where pH (5.7) and the concentration of the competing solutes phosphate (2.3 micromolar) and sulfate (86 micromolar) were low. Adsorption of molybdate decreased with depth as pH increased to 6.5, phosphate increased to 40 micromolar, and sulfate increased to 340 micromolar. A one-site diffuse-layer surface-complexation model and a two-site diffuse-layer surface-complexation model were used to simulate adsorption. Reactions and equilibrium constants for both models were determined in laboratory experiments and used in the reactive-transport model PHAST to simulate the two-dimensional transport of molybdate during the tracer test. No geochemical parameters were adjusted in the simulation to improve the fit between model and field data. Both models simulated the travel distance of the molybdate cloud to within 10% during the 2-year tracer test; however, the two-site diffuse-layer model more accurately simulated the molybdate concentration distribution within the cloud.

Stollenwerk, K. G.

1998-01-01

165

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

2012-11-01

166

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

Code of Federal Regulations, 2010 CFR

...from transportation control measures (TCMs...plan which restrict vehicle usage based primarily...temporal element is secondary to some other control element and, in...does not include access to high occupancy vehicle (HOV) lanes,...

2010-07-01

167

Pilot workload in the air transport environment : measurement, theory, and the influence of air traffic control  

E-print Network

The operating environment of an air transport crew is characterized by multiple interrupting tasks, these tasks being composed of a mixture of purely physical control and purely mental planning processes. Measurement of ...

Katz, Jeffrey G.

1980-01-01

168

Measurement of electronic transport through 1G0 gold contacts under laser irradiation.  

PubMed

Metal quantum point contacts (MQPCs) with dimensions comparable to the de Broglie wavelength of conducting electrons reveal ballistic transport of electrons and quantized conductance in units of G(0) = 2e(2)/h. We measure the transport properties of 1G(0) Au contacts under laser irradiation. The observed enhancement of conductance appears to be wavelength-dependent, while thermal effects on conductance are determined to be negligible. For wavelengths that are not absorbed by Au, the results are consistent with a photoassisted transport mechanism in which conductance depends both on the electronic structure of the leads and on the interaction of the transporting electrons with oscillating electric fields originating from excitation of local plasmons. For wavelengths absorbed by Au, photoinduced mechanism is suggested to be the dominant transport mechanism. The results demonstrate optical control of ballistic transport in MQPCs and are also important for future interpretation of light effects on the conductance of single-molecule junctions. PMID:19317478

Ittah, Naomi; Noy, Gilad; Yutsis, Ilan; Selzer, Yoram

2009-04-01

169

Air transport flight parameter measurements program - Concepts and benefits  

NASA Technical Reports Server (NTRS)

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

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

1980-01-01

170

Monitoring electrostatic flow noise for mass flow and mean velocity measurement in pneumatic transport  

Microsoft Academic Search

This paper presents experimental results of research on the electrostatic, non-contact measurement of the mass flow rate and mean flow velocity of solids in pneumatic transport lines. We also describe a microprocessor-based system, based on the measurement method, that had been built to be installed in industrial installations. The system permits rapid mass flow rate and mean flow velocity measurements

Juliusz B. Gajewski

1996-01-01

171

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

E-print Network

The measurable heat flux that accompanies active transport by Ca2+ -ATPase Dick Bedeauxw and Signe how the measurable heat flux and the heat production under isothermal conditions, as well of measurements, that the heat production in active trans- port is significant and varies. These authors studied

Kjelstrup, Signe

172

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

E-print Network

Effect of sidewall conductance on heat-transport measurements for turbulent Rayleigh, California 93106 Received 31 July 2000; published 27 December 2000 For measurements of turbulent heat or based on measurements or estimates for the empty cell. It is argued that the lateral thermal coupling

Fygenson, Deborah Kuchnir

173

Reliability as a measure of transportation system performance  

E-print Network

This investigation involved a comparative analysis to assess the quantitative and qualitative characteristics of seven previously proposed methods of measuring travel time reliability. For each method, reliability was calculated using a l2-week...

Jackson, Dena Delise

2012-06-07

174

Thermal Transport Measurement of Silicon-Germanium Nanowires  

E-print Network

???????????????????..??..6 CHAPTER II THERMAL CONDUCTIVITY MEASUREMENT FOR ONE DIMENSIONAL NANOMATERIALS??????.??....8 2.1 Batch-fabricated micro-device for thermal conductivity measurement.8 2.2 Sample preparation of SiGe nanowire..????....???????..9 2.3 Experimental... 5 SEM image of SiGe nanowire which was successfully bridged between the two membranes. Low thermal contact resistance is achieved using FIB(focused ion beam)????????.??... 11 FIGURE 6 Schematic diagram of the experimental setup for thermal...

Gwak, Yunki

2010-10-12

175

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

SciTech Connect

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

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

2010-10-28

176

[Simulation of strangulation findings by postmortem rescue and transport measures].  

PubMed

Improper rescue or transportation of a corpse by gripping the neck or using a sling can cause traumatization that might erroneously suggest strangulation in subsequent autopsy. On the basis of 3 observations, postmortal damages which, at first sight, had seemed suspicious are presented and discussed. In the first case a drowned person's neck showed a dried skin line simulating a strangulation by ligature. The 2nd case dealt with a male person who had died ventricumbent in consequence of an apoplectic cerebral haemorrhage, and who had been lifted by embracing the neck shortly after death; at the post-mortem examination, massive blood extravasations were found in the cervical musculature. In the 3rd case, a strap was slung around the neck of a male epileptic--subsequently found to have served for carrying a saxophone. Both great hornes of the thyroid cartilage were fractured. Inquiry revealed that the undertakers had used the sling to hoist the corpse in which changes due to decomposition had already developed. PMID:2818521

Zollinger, U; Pollak, S

1989-01-01

177

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

PubMed

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

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

2013-01-01

178

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

179

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

NASA Astrophysics Data System (ADS)

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

2012-05-01

180

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

181

A rigorous bound on the vertical transport of heat in Rayleigh-Bénard convection at infinite Prandtl number with mixed thermal boundary conditions  

NASA Astrophysics Data System (ADS)

A rigorous upper bound on the Nusselt number is derived for infinite Prandtl number Rayleigh-Bénard convection for a fluid constrained between no-slip, mixed thermal vertical boundaries. The result suggests that the thermal boundary condition does not affect the qualitative nature of the heat transport. The bound is obtained with the use of a nonlinear, stably stratified background temperature profile in the bulk, notwithstanding the lack of boundary control of the temperature due to the Robin boundary conditions.

Whitehead, Jared P.; Wittenberg, Ralf W.

2014-09-01

182

Continuous measurements of bedload transport rates in a small glacial river catchment in the summer season (Spitsbergen)  

NASA Astrophysics Data System (ADS)

The study on bedload transport was conducted on the gravel-bed Scott River catchment with a glacial alimentation regime, located in the NW part of the Wedel Jarlsberg Land (Spitsbergen) with subpolar climatic conditions. In the melt season of 2010, bedload transport rate was continuously monitored at 24-hour intervals by means of four River Bedload Trap devices aligned across the width of the channel. The maximum bedload transport rate varied strongly at portions of the cross section from 16 to 152 kg m- 1 d- 1 in cross-profile I (c-p I) and 4 to 125 kg m- 1 d- 1 in cross-profile II (c-p II). The maximum channel-mean bedload transport rate (qa) amounted to 54 kg m- 1 d- 1 (c-p I) and 35 kg m- 1 d- 1 (c-p II). Mean daily bedload discharge (Qb) was estimated at a level of 97 kg day- 1 (c-p I) and 35 kg m- 1 d- 1 (c-p II), and the total bedload yield was determined at approx. 4345 kg in the measurement period (2086 kg — c-p I; 2203 kg — c-p II from 13.07 to 10.08). The analysis of the relationship between channel-mean bedload transport rate and water velocity or shear stress revealed a significant value of the correlation coefficient (R2 = 0.6). Discharge and rate of bedload transport were dependent on the weather and number of days with flood discharge. Approx. 58% of the entire discharged bedload was transported during 3 violent ablation-precipitation floods. Bedload grain size distribution was right-skewed and showed moderate sorting.

Kociuba, Waldemar; Janicki, Grzegorz

2014-05-01

183

Implications of an Uncertainty and Sensitivity Analysis for SARS' Basic Reproductive Number for General Public Health Measures  

E-print Network

consider the outbreak in Hong Kong. The value 2061! = . means that the mean time to diagnose an infectedImplications of an Uncertainty and Sensitivity Analysis for SARS' Basic Reproductive Number for General Public Health Measures Appendix I: Local Sensitivity Analysis of the Basic Reproductive Number G

Chowell, Gerardo

184

Volume 152, number 4,s CHEMICAL PHYSICS LETTERS 18 November 1988 NON-INTRUSIVE MEASUREMENT OF AXIAL ELECTRIC FIELDS  

E-print Network

Volume 152, number 4,s CHEMICAL PHYSICS LETTERS 18 November 1988 NON-INTRUSIVE MEASUREMENT OF AXIAL ) 419 #12;volume 152. number 4.5 CHEMICAL PHYSICS LETTERS I8 November 198X determining the axial electri ELECTRIC FIELDS IN LOW-PRESSURE GLOW DISCHARGES BY VELOCITY MODULATION LASER SPECTROSCOPY Michael B

Cohen, Ronald C.

185

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

SciTech Connect

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

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

2005-05-31

186

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

NASA Astrophysics Data System (ADS)

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

Boucher, Vincent; Dumoulin, Jean

2014-05-01

187

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

PubMed

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

Errard-Lalande, G; Halimi, A

2005-04-01

188

Using High Time Resolution Aerosol and Number Size Distribution Measurements to Estimate Atmospheric Extinction  

Microsoft Academic Search

Rocky Mountain National Park is experiencing reduced visibility and changes in ecosystem function due to increasing levels of oxidized and reduced nitrogen. The Rocky Mountain Atmospheric Nitrogen and Sulfur (Ro-MANS) study was initiated to better understand the origins of sulfur and nitrogen species as well as the complex chemistry occurring during transport from source to receptor. As part of the

William C. Malm; Gavin R. McMeeking; Sonia M. Kreidenweis; Ezra Levin; Christian M. Carrico; Derek E. Day; Jeffrey L. Collett Jr; Taehyoung Lee; Amy P. Sullivan; Suresh Raja; Charles McDade; Ann Dillner; Hege Indresand; Jeffrey Collett; Marc Pitchford; Richard Poirot; Bret Schichtel; Patricia Brewer; Tom Moore; Mark Green; Shobha Kondragunta; Pubu Ciren; Chuanyu Xu; Delbert Eatough; Robert Farber; Marco Rodriguez; Michael Barna

2009-01-01

189

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

Code of Federal Regulations, 2012 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,...

2012-01-01

190

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,...

2013-07-01

191

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

Code of Federal Regulations, 2011 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,...

2011-01-01

192

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

Code of Federal Regulations, 2010 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,...

2010-07-01

193

Macroscale lattice-Boltzmann methods for low Peclet number solute and heat transport in heterogeneous porous media  

Microsoft Academic Search

This paper introduces new methods for simulating subsurface solute and heat transport in heterogeneous media using large-scale lattice-Boltzmann models capable of representing both macroscopically averaged porous media and open channel flows. Previous examples of macroscopically averaged lattice-Boltzmann models for solute and heat transport are only applicable to homogeneous media. Here, we extend these models to properly account for heterogeneous pore-space

S. D. C. Walsh; M. O. Saar

2010-01-01

194

Measurements and heat-flux transport modelling in a heated cylinder wake  

Microsoft Academic Search

Hot-wire measurements of velocity and temperature fluctuations have been made in the self-preserving turbulent wake region of a heated cylinder. Second order statistics including Reynolds fluxes, ui?, are determined along with relevant triple correlations appearing in the Reynolds stress and Reynolds flux transport equations. The primary aim with these measurements is to study different modelling levels for passive scalar quantities.

Petra M. Wikström; Magnus Hallbäck; Arne V. Johansson

1998-01-01

195

Electron Heat Transport Measured in a Stochastic Magnetic Field T. M. Biewer,* C. B. Forest,  

E-print Network

Electron Heat Transport Measured in a Stochastic Magnetic Field T. M. Biewer,* C. B. Forest, J. K where magnetic islands overlap and field lines are stochastic. The measurements show that (1 are small, the magnetic field lines break into chains of magnetic islands at mode-rational sur- faces where

Biewer, Theodore

196

Resonant Acoustic Measurement of Vapor Phase Transport Phenomenon  

NASA Astrophysics Data System (ADS)

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

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

2002-12-01

197

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

NASA Technical Reports Server (NTRS)

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

Igoe, William B.

1991-01-01

198

PROBLEMS IN THE MEASUREMENT OF EDUCATIONAL TELEVISION CONSUMPTION, PRELIMINARY REPORT NUMBER 4--EDUCATIONAL TELEVISION PROJECT.  

ERIC Educational Resources Information Center

THE SPECIFIC PROBLEM OF THIS REPORT WAS TO EXPLORE THE INSTANCE OF MEASUREMENT ERROR ASSOCIATED WITH COMMONLY USED MEASURES OF EDUCATIONAL TELEVISION (ETV) CONSUMPTION BY VIEWERS. THE AMOUNT OF RESPONDENT MISREPRESENTATION THAT MAY BE INVOLVED IN THE USE OF A PARTICULAR MEASUREMENT TECHNIQUE AND THE REASONS WHY IT OCCURS WERE STUDIED. IN ORDER TO…

MEISSNER, MARTIN

199

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

200

Testing Observational Tracers of Turbulence with Numerical Simulations: Measuring the Sonic Mach Number in Molecular Clouds  

NASA Astrophysics Data System (ADS)

Astrophysical simulations provide a unique opportunity to test and verify observational diagnostics of the physics of the interstellar medium. In these proceedings, we highlight how s imulations of MHD turbulence can increase the accuracy and understanding of observational tracers of important plasma parameters, such as the sonic Mach number, in molecular clouds. For this purpose we analyze MHD simulations which include post-processing to take radiative transfer effects of 13CO emission and absorption into account. We find very good agreement between the linewidth estimated sonic Mach number and the actual sonic Mach number of the simulations for optically thin 13CO. However, we find that opacity broadening causes Ms to be overestimated by a factor of ? 1.16–1.3 when calculated from optically thick 13CO lines. We also find that there is a dependency on the magnetic field: super-Alfvénic turbulence shows increased line broadening as compared with sub-Alfvénic turbulence for all values of optical depth for the line of sight perpendicular to an magnetic field. These results have implications for the observationally derived sonic Mach number–density standard deviation (??/) relationship, ?2?/=b2M s2, and the related column density standard deviation (?N/(N)) sonic Mach number relationship, which we briefly discuss. The turbulence sonic Mach number is an important parameter of star formation models and the results highlighted in these proceedings provide researchers with increased understanding of these parameters derived from observations.

Burkhart, B.; Lazarian, A.; Correia, C.; Ossenkopf, V.; Stutzki, J.; de Medeiros, J. R.

2014-09-01

201

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

PubMed Central

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.

2013-01-01

202

Transportation  

Microsoft Academic Search

India, a country over one billion population has been facing serious difficulty of urban congestion and traffic jams since 1970's in her major cities. Public transport system in Mumbai has been overworking three times its capacity. Public transport system in Delhi, Colcutta and Chennai is also under strain. Elevated railway and underground railway could be options to support overworked surface

Makarand Gulawani

203

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

204

Nitrite transport in chloroplast inner envelope vesicles. I. Direct measurement of proton-linked transport  

SciTech Connect

Chloroplast inner envelope membrane vesicles that are loaded with the pH-sensitive fluorophore, pyranine, show rapid internal acidification when nitrite is added. Acidification is dependent upon {Delta}pH, with the inside of vesicles being alkaline with respect to the outside. The rate of vesicle acidification was directly proportional to the concentration of nitrite that was added and the imposed pH difference across the membrane. In contrast, added nitrate had no effect on vesicle acidification. Nitrite also caused acidification of asolectin vesicles that were prepared by extrusion were approximately the same size, allowing them to be compared when the final extent of acidification, measured after the pH gradient had collapsed, was similar. The rate of nitrite-dependent acidification was similar in these two preparations at any single nitrite concentration. These results indicate that nitrite movement occurs by rapid diffusion across membranes as nitrous acid, and this movement is dependent on a proton gradient across the lipid bilayer. Under conditions approximating these in vivo, the rate of diffusion of nitrous acid far exceeds that of nitrite reduction within chloroplasts. 26 refs., 5 figs., 1 tab.

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

1996-11-01

205

Measuring and modelling the local-scale spatio-temporal variation of urban particle number size distributions and black carbon  

NASA Astrophysics Data System (ADS)

Mobile measurements were performed to study the spatio-temporal variation of particle number size distributions (NSD) in the range 11 < Dp < 365 nm as well as total particle number and black carbon concentrations in Braunschweig, Germany during the winter and summer period 2012/2013. The study area of about 1 km2 consisted of six different outdoor microenvironments (ME) that were classified according to different traffic intensities and dominant land use types along the measurement route. Highest averaged total number concentrations measured at roadside (RO) were 2.5 × 104 pt cm-3 (with a maximum of 7.6 × 104 pt cm-3) during winter and about 1.2 × 104 pt cm-3 on average during the summer campaign. Measurement spots which are more distant to traffic were characterised by lower concentrations of 1.6 × 104 pt cm-3 and 9.0 × 103 pt cm-3 during winter and summer, respectively. Black carbon (BC) concentrations were also clearly related to traffic emissions and resulted in concentrations of 2.8 ?g m-3 on average (absolute maximum of 6.2 ?g m-3) at RO-sites. The concentrations of particles and BC in the different ME (aggregated from the single measurement spots) documented the concentration of both metrics to be a function of distance of the measurement to fresh traffic emissions. A multiple regression based model was established to identify significant parameters which can be used to model the microscale variation of particle NSD in the outdoor ME. Two models with different numbers of input parameters were calculated. The first contained all measured parameters as input, the second only a reduced number consisting of TNC, BC and wind speed. Both models worked convincingly, even the approach with the limited number of input parameters. The average size integrated (TNC) deviation to observed data in all ME during both seasons was <13%. The best agreement between model and observations is given for the near-traffic ME.

Ruths, Matthias; von Bismarck-Osten, Clemens; Weber, Stephan

2014-10-01

206

The Influence of Atmospheric Transport Regimes on Polychlorinated Biphenyl (PCB) Concentrations Measured at Zeppelin  

NASA Astrophysics Data System (ADS)

Polychlorinated biphenyls (PCBs) are persistent organic pollutants (POPs) of exclusively anthropogenic origin. PCBs are toxic, bioaccumulative and have a great potential of long-range transport. PCBs have been banned globally under the Stockholm convention on POPs since 2004. We analysed times series of 21 PCB congeners ranging from PCB 18 to PCB 187 that have been measured at Zeppelin (Spitsbergen) since 1993. Although primary PCB emissions have been steadily reduced, a strong decreasing trend is not observed in the PCB concentrations in the Arctic. In order to investigate the influence of atmospheric transport on the PCB concentrations and to identify the potential source regions of the PCBs, we calculated footprints for the Zeppelin measurement site using the Lagrangian Particle Dispersion Model FLEXPART. Footprints can be interpreted as potential source regions where PCBs may have been picked up. Based on various statistical analyses of the footprints (cluster analysis, k-medoid, silhouette), we identified the prevailing transport regimes for Zeppelin which were represented by 5 different clusters. Cluster 1 and 3 belong to transport regimes with highest residence times over Europe (cluster 1) and North-America (cluster 3); both transport regimes dominantly occur from late fall to early spring. Clusters 2 and 4 represent air masses with surface contact predominantly over the Atlantic Ocean (cluster 2), only occurring during the summer months, and the Arctic Ocean (cluster 4) mainly observed in spring and autumn, but also in summer. Cluster 5 is representative of air originating from the Pacific ocean and eastern Asia; this transport regime occurs mainly in spring and fall. We grouped the PCB concentrations measured at Zeppelin according to the 5 different clusters and calculated the median for each cluster and PCB congener. The median for medium to heavier PCBs is highest for cluster 1 and 3, which represent transport regimes over the continent, suggesting that emissions of the respective PCBs dominantly occur over land. However, for the lighter congeners (PCB-18-PCB-47) the highest median concentration corresponds to cluster 2 and the lowest to cluster 3 and 5. The high concentration of the lighter congeners resulting from the transport over the ocean, represented by clusters 2 and to some extent 4, cannot be explained by primary PCB emissions. Also the use of a temperature-dependent primary PCB emission inventory did not resolve this apparent contradiction between high PCB concentrations and a transport regime under which Zeppelin does not receive air from the continents. Our data therefore suggest that in addition to atmospheric transport regimes and primary PCB emissions, also other factors such as secondary emissions from the ocean and/or from soils strongly influence the concentrations of lighter PCBs measured at Zeppelin.

Ubl, S.; Scheringer, M.; Hungerbuehler, K.

2013-12-01

207

Understanding the effects of the number of pyrazines and their positions on charge-transport properties in silylethynylated N-heteropentacenes.  

PubMed

The charge-transport properties of a series of silylethynylated N-heteropentacenes (TIPS-PEN-xN; x = 2, 4) were systematically investigated using Marcus electron-transfer theory coupled with kinetic Monte Carlo simulations. Electronic structure calculations showed that introducing more pyrazine rings decreases the energy levels of the lowest unoccupied molecular orbitals (LUMOs) and should aid electron transfer. The number and the positions of the pyrazine rings greatly influence the molecular packing in crystals and hence the intermolecular electronic coupling. Furthermore, the introduction of internal (rather than external) pyrazine rings leads to a better charge-transport network. Transport parameters evaluated from the hopping and band-like models both demonstrate that, among the TIPS-PEN-xN molecules, B-TIPS-PEN-4N-which has two internal pyrazine rings-is the most promising n-type material. PMID:25367043

Zhang, Shou-Feng; Chen, Xian-Kai; Fan, Jian-Xun; Guo, Jing-Fu; Ren, Ai-Min; Li, Yu-Wei

2014-11-01

208

Volume 134. number I CHEMICAL PHYSICS LETTERS 13 February 1987 STIMULATED RADIATIVE DISSOCIATION AND GAIN MEASUREMENTS  

E-print Network

been demonstrated in electron-beam-pumped high-pressure gas cells [ 31. We have performed gain. The analogy to the four-level laser is also appropri- ate for gas phase and liquid phase xenon chloride measurements in both solid and liquid xenon, the liquid xenon measurements will be reported in the subsequent

Apkarian, V. Ara

209

Use of Subharmonically Pumped SIS Mixer with High Harmonics Number for Phase and Amplitude Antenna Measurements  

Microsoft Academic Search

For the ALMA Interferometer and FIRST Mission a means of measuring accurately the phase and amplitude of horns and other antenna structure in the submillimeter bands is required to ensure good alignment and high coupling efficiencies to the telescopes. This paper gives a means for making these measurements by using a SIS junction as a sub harmonically pumped mixer. The

A. Baryshev; M. Carter; R. Hesper; S. J. Wijnholds; W. Jellema; T. Zijlstra

2002-01-01

210

Measuring Institutional Capacity. Recent Practices in Monitoring and Evaluation Tips, Number 15.  

ERIC Educational Resources Information Center

This document provides information for managers in the U. S. Agency for International Development on measuring institutional capacity, including some tools that measure the capacity of an entire organization as well as others that look at individual components or functions of an organization. The paper defines and discusses capacity assessment in…

Lessik, Alan; Michener, Victoria

211

An integrated approach for measuring copy number variation at the FCGR3 (CD16) locus  

PubMed Central

Copy number variation (CNV) is an important source of genomic diversity in humans, and influences disease susceptibility. The immunoglobulin-receptor genes FCGR3A and FCGR3B on chromosome 1q23.3 show CNV, and CNV of the FCGR3B gene is associated with glomerulonephritis in systemic lupus erythematosus and organ-specific autoimmunity. Large-scale case-control association studies of CNV require technologies that are amenable to high-throughput analysis with low error rates. Here we propose an integrated suite of five assays, four of them duplexed to reduce DNA usage, that assays for copy number variation at FCGR3A and FCGR3B, and genotype the polymorphic neutrophil antigen HNA1. We show how a maximum-likelihood approach to combining the results from these five assays allows estimation of statistical confidence for each individual copy number, and therefore an appropriate significance threshold to be set, controlling the error rate. This approach results in a high-throughput copy number genotyping system, with demonstrable precision and accuracy, that can be applied to large case-control cohort studies. We demonstrate Mendelian inheritance of this CNV, variation in frequency between Europeans and East Asians, and a lack of strong association between the CNV and flanking SNP genotypes, with important consequences for genome-wide association studies. PMID:19143032

Hollox, Edward J.; Detering, Jan-Christoph; Dehnugara, Tushna

2013-01-01

212

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

213

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

ERIC Educational Resources Information Center

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

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

2008-01-01

214

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

NASA Astrophysics Data System (ADS)

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

Kouwenhoven, Erik; Giezen, Marina; Struikmans, Henk

2009-05-01

215

The Measurement and Application of Transport Properties of Ion Swarms in Gases.  

NASA Astrophysics Data System (ADS)

The drift velocities, mobilities, and longitudinal diffusion coefficients of the ion-gas combinations Tl('+) in He, Ne, Ar, and O(,2), Cl('-) in N(,2) and NO('+) in N(,2) were measured at constant room temperature as a function of E/N, where E is the electric field strength and N is the number density of the neutral gas. T measured mobilities of Tl('+) in Ar were used to determine the ion-neutral interaction potential. The measured mobilities of Cl(' -) in N(,2) were used to determine an effective ion-neutral interaction potential. Cross sections for momentum transfer were calculated as a function of ion-neutral collision energy in the center-of-mass frame from the directly determined ion-neutral interaction potentials for the Tl('+) in Ar and Cl('-) in N(,2) gas combinations. The data taken as a function of E/N were obtained in a low pressure drift tube mass spectrometer. For this study the Tl('+) ions were obtained by thermionic emission from a specially coated filament while the Cl('-) and NO('+) ions were generated by electron bombardment of trace gases. Arrival time histograms were built up for the mass-selected ions. From the histograms, the average arrival times, drift velocities, and hence, mobilities were calculated. Longitudinal diffusion coefficients were determined by fitting theoretical curves to the measured arrival time histograms. The interaction potentials were determined from the measured mobilities by an iterative-inversion scheme. The ion mobilities and longitudinal diffusion coefficients were measured over as wide and E/N range as possible as follows: Tl('+) in He (6 - 70 Td), Tl('+) in Ne (7 - 81 Td), Tl('+) in Ar (10 - 369 Td) Tl('+) in O(,2) (20 - 229 Td), Cl('-) in N(,2) (8 - 264 Td), and NO('+) in N(,2) (5 - 307 Td). The longitudinal diffusion coefficients were compared to those given by the generalized Einstein relations given by Waldman and Mason's three-temperature theory. Using the Viehland-Mason kinetic theory for gaseous ion transport, the experimental mobilities of Tl('+) in Ar and Cl('-) in N(,2) were related to the omega integrals. Initial theoretical 4-6-n type potentials were used in an iterative process until a good match between the experimental and theoretical mobilities was obtained. The values of the potentials as a function of ion-molecule separation distance were tabulated. The tabulated potentials were used to calculate diffusion cross sections over the range of center -of-mass frame collision energy of .00145 - 408 eV for the Tl('+)-Ar and Cl('-)-N(,2) ion-gas systems. The relevance of ion transport data to the applications of magnetospheric-ionospheric coupling, incoherent radar backscattering, and extremely low frequency (ELF) radio propogation was discussed.

Holleman, Franklin Benton

216

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

217

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

NASA Technical Reports Server (NTRS)

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

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

1978-01-01

218

Measurement of dose enhancement close to high atomic number media using optical fibre thermoluminescence dosimeters  

NASA Astrophysics Data System (ADS)

Present interest concerns development of a system to measure photoelectron-enhanced dose close to a tissue interface using analogue gold-coated doped silica-fibre thermoluminescence detectors and an X-ray set operating at 250 kVp. Study is made of the dose enhancement factor for various thicknesses of gold; measurements at a total gold thickness of 160 nm (accounting for incident and exiting photons) produces a mean measured dose enhancement factor of 1.33±0.01 To verify results, simulations of the experimental setup have been performed.

Alalawi, Amani I.; Hugtenburg, R. P.; Abdul Rahman, A. T.; Barry, M. A.; Nisbet, A.; Alzimami, Khalid S.; Bradley, D. A.

2014-02-01

219

Measurement of electron spin transport in graphene on 6H-silicon carbide(0001)  

NASA Astrophysics Data System (ADS)

The focus of this thesis is to demonstrate the potential of wafer scale graphene spintronics. Graphene is a single atomic layer of sp 2-bonded carbon atoms that has high carrier mobilities, making it a desirable material for future nanoscale electronic devices. The vision of spintronics is to utilize the spin of the electron to produce novel high-speed low power consuming devices. Materials with long spin relaxation times and spin diffusion lengths are needed to realize these goals. Graphene is an ideal material as it meets these requirements and is amenable to planar device geometries. In this thesis, spin transport in wafer scale epitaxial graphene grown on the silicon face of silicon carbide is demonstrated. Non-local Hanle spin precession measurement devices were fabricated using graphene with and without a hafnium oxide interface layer between the ferromagnetic metal and graphene. The structural properties of the devices were investigated with Raman spectroscopy, x-ray photoelectric spectroscopy, Rutherford backscattering spectroscopy, scanning electron microscopy, atomic force microscopy, and transmission electron microscopy. The electrical properties of the graphene were measured utilizing Hall transport measurements. The magnetic properties of the contacts were investigated with vibrating sample magnetometery. The processes developed to fabricate the Hanle measurement devices are presented as well. A custom Hanle measurement setup was developed and utilized for the Hanle spin precession measurements. Spin precession is observed in the epitaxial graphene on silicon carbide, with improved spin transport properties with the utilization of a hafnium oxide barrier between the ferromagnetic contacts and graphene. The charge transport and spin transport properties are compared to determine the relevant spin relaxation mechanism in the devices. These results demonstrate that graphene has great potential for wafer scale production of future spintronic devices.

Abel, Joseph

220

Extending the Capabilities of Single Particle Mass Spectrometry: I. Measurements of Aerosol Number Concentration, Size Distribution, and Asphericity  

SciTech Connect

Single particle mass spectrometers have traditionally been deployed to measure the size and composition of individual particles at relatively slow sampling rates that are determined by the rate at which the ionization lasers can fire and/or mass spectra can be recorded. To take advantage of the fact that under most conditions SPLAT can detect and size particles at much higher rates we developed a dual data acquisition mode, in which particle number concentrations, size distributions, and asphericity parameters are measured at a particle concentration determined rate, all the while the instrument generates and records mass-spectra at an operator set rate. We show that with this approach particle number concentration and asphericity parameters are measured with 1 sec resolution and particle vacuum aerodynamic size distributions are measured with 10 sec to 60 sec resolution. SPLAT measured particle number concentrations are in perfect agreement with the PCASP. Particle asphericity parameters are based on measured particle beam divergence. We illustrate the effect that high particle concentrations can have on the measured size distributions and develop a method to remove these effects and correct the size distributions.

Vaden, Timothy D.; Imre, D.; Beranek, Josef; Zelenyuk, Alla

2011-01-04

221

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

222

Measuring effects of voluntary attention: A comparison among predictive arrow, colour, and number cues.  

PubMed

The Posner cueing paradigm is one of the most widely used paradigms in attention research. Importantly, when employing it, it is critical to understand which type of orienting a cue triggers. It has been suggested that large effects elicited by predictive arrow cues reflect an interaction of involuntary and voluntary orienting. This conclusion is based on comparisons of cueing effects of predictive arrows, nonpredictive arrows (involuntary orienting), and predictive numbers (voluntary orienting). Experiment 1 investigated whether this conclusion is restricted to comparisons with number cues and showed similar results to those of previous studies, but now for comparisons to predictive colour cues, indicating that the earlier conclusion can be generalized. Experiment 2 assessed whether the size of a cueing effect is related to the ease of deriving direction information from a cue, based on the rationale that effects for arrows may be larger, because it may be easier to process direction information given by symbols such as arrows than that given by other cues. Indeed, direction information is derived faster and more accurately from arrows than from colour and number cues in a direction judgement task, and cueing effects are larger for arrows than for the other cues. Importantly though, performance in the two tasks is not correlated. Hence, the large cueing effects of arrows are not a result of the ease of information processing, but of the types of orienting that the arrows elicit. PMID:24697668

Olk, Bettina; Tsankova, Elena; Petca, A Raisa; Wilhelm, Adalbert F X

2014-10-01

223

UARS/MLS Cloud Ice Measurements: Implications for H2O Transport near the Tropopause  

E-print Network

to ice (RHi) at 100 hPa during both the dry (January­ March) and moist (July­September) periods. 1UARS/MLS Cloud Ice Measurements: Implications for H2O Transport near the Tropopause D. L. WU AND W ice clouds and are sensitive to ice crystals of convective origin. Rough ice water content (IWC

Sherwood, Steven

224

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...

225

MEASUREMENT OF TRANSPORT PROPERTIES FOR THE DRIED LAYER OF COFFEE SOLUTION UNDERGOING FREEZE DRYING  

Microsoft Academic Search

A mathematical model has developed to determine the thermal conductivity and permeability for the dried layer of liquid sample undergoing sublimation dehydration. A microcomputer-based automatic measurement system has developed for the data acquisition as well as determination of these transport properties applying the drying data to the model. Aqueous solutions of 29-45 % soluble coffee solid were freeze dried under

Yasuyuki Sagara; Jum-ichi Ichiba

1994-01-01

226

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.

227

Oxygen transport in zeolite Y measured by quenching of encapsulated tris(bipyridyl)ruthenium  

E-print Network

reserved. Keywords: Oxygen sensor; Zeolite diffusion; Zeolite confinement 1. Introduction The microporousOxygen transport in zeolite Y measured by quenching of encapsulated tris(bpy)2þ 3 ) by oxygen. Oxygen saturated solutions of Ru(bpy)2þ 3 typically show about 70% quenching (I0=I

Dutta, Prabir K.

228

WELFARE MEASURES TO REFLECT HOME LOCATION OPTIONS WHEN1 TRANSPORTATION SYSTEMS ARE MODIFIED2  

E-print Network

and scenario43 extensions are feasible, which may highlight other key factors for regional welfare analysis44 new-highway impacts: opportunities for15 welfare analysis and credit-based congestion pricing 1 WELFARE MEASURES TO REFLECT HOME LOCATION OPTIONS WHEN1 TRANSPORTATION SYSTEMS

Kockelman, Kara M.

229

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

E-print Network

Eddy-Induced Heat Transport in the Subtropical North Pacific from Argo, TMI, and Altimetry Measurements BO QIU AND SHUIMING CHEN Department of Oceanography, University of Hawaii at Manoa, Honolulu, Hawaii (Manuscript received 16 April 2004, in final form 18 August 2004) ABSTRACT Basin-scale heat

Qiu, Bo

230

Fast modeling of borehole neutron porosity measurements with a new spatial transport-diffusion approximation  

E-print Network

diffusion solution is im- plemented for nonmultiplying systems in 2D and 3D cylindrical coordinatesFast modeling of borehole neutron porosity measurements with a new spatial transport-diffusion)-derived spatial flux sensitivity functions (FSFs) and diffusion flux-difference (DFD) approximations. The method

Torres-Verdín, Carlos

231

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...

232

Thermoelectric and Magnetothermoelectric Transport Measurements of Graphene Yuri M. Zuev,1  

E-print Network

Thermoelectric and Magnetothermoelectric Transport Measurements of Graphene Yuri M. Zuev,1 Willy, USA (Received 7 December 2008; published 6 March 2009) The conductance and thermoelectric power (TEP of thermal and thermoelectric prop- erties of this two-dimensional material [2­8], only an indirect

Kim, Philip

233

An automated system for measuring the mass flowrate of powders in transport lines  

NASA Astrophysics Data System (ADS)

A new automated particle transport (APT) system has been developed for studying the dissemination of bulk powders into deagglomerated aerosols. It consists of a 1.12-inch ID transport line with a spout-fluidized bed feeder. The particles are transported from an aerated annulus into the transport line and collected in a closed can or bag filter. Two separate feed lines supply the air necessary to operate the transport line and aerate the particles in order that they flow smoothly into the transport line. An IBM PC AT computer clone equipped with a data translation DT 2806 multifunction input-output board and A to D and D to A modules (DTX 311 and 328) is used for both control and data acquisition. A fluid mechanical model of the flow has been developed and the APT system will be used to verify it. Experiments will be conducted to measure the choking velocity, drag coefficient, fluid and particle flowrates, and pressure distribution in the line.

Littman, Howard; Morgan, Morris B., III; Prapas, Demetrios K.; Rubel, Glen O.

1990-08-01

234

GIS measured environmental correlates of active school transport: A systematic review of 14 studies  

Microsoft Academic Search

Background  Emerging frameworks to examine active school transportation (AST) commonly emphasize the built environment (BE) as having\\u000a an influence on travel mode decisions. Objective measures of BE attributes have been recommended for advancing knowledge about\\u000a the influence of the BE on school travel mode choice. An updated systematic review on the relationships between GIS-measured\\u000a BE attributes and AST is required to

Bonny Yee-Man Wong; Guy Faulkner; Ron Buliung

2011-01-01

235

Measurements of the effect of a magnetic field on the transport of linear momentum in nitrogen  

E-print Network

Introduction II Related Work The Senftleben Effect The Scott Effect III Experimental Method: Apparatus and Procedure IV Measurements and Results 14 Bibliography 22 LIST OF FIGURES 1. Schematic of Apparatus 2. Approach to Saturation 3. New Data... and Senftleben Effect 19 20 4. New Data, Senftleben Effect, and Scott Effect 21 LIST OF TABLES 1. Set of Representative Data 12 CHAPTER I INTRODUCTION Measurements have been made of the effect of a magnet1c field on momentum transport 1n gaseous nitrogen...

Larchez, Mark Edward

2012-06-07

236

Measurement of thermal transport using time-resolved thermal wave microscopy  

SciTech Connect

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

Marat Khafizov; David H. Hurley

2011-10-01

237

Development of high speed continuous transport critical current measurement system for long piece of HTS conductor  

NASA Astrophysics Data System (ADS)

In case of long pieces of HTS conductor, their critical current measurement is an important process for the conductor manufacturer and the customer, however, it is very time consuming process. Conventional critical current measurement is carried out by ‘four probe method’, which increase the transport current and measure the voltage between the fixed voltage taps. Therefore, it consists of conductor moving and measuring process. To speed up the measuring process, longer distance between voltage taps is required. In this case, the measured critical current is averaged and small defects, which can be very crucial for thermal stability, cannot be found. Therefore, the limitation of the voltage tap length should be carefully decided considering the cooling environment. Another non-contact or indirect method is to measure the screening effect of magnetic field and converting the field signal to the critical current, which is called as hall probe method. This process is known as a very efficient way to find local defects and estimate the distribution of the critical current, however, it contains inevitable error and noise because it should measure the small magnetic field signals. This paper describes a new critical current measurement system, which have similar hardware structure of conventional ‘four probe method’. However, it is much faster than other systems using fast feedback control of the transport current while the conductor is continuously moving with high speed. The measured results are compared with the conventional method and hall probe method.

Kim, Seokho; Park, Minwon; Yu, In-Keun; Kim, Gyeong-Hun; Ha, Hong-Su; Sim, Kideok; Oh, Sang-Soo; Moon, Seung-Hyun

2013-01-01

238

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

239

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

PubMed

Sea level measurements from tide gauges at Miami, Florida, and Cat Cay, Bahamas, and bottom pressure measurements from a water depth of 50 meters off Jupiter, Florida, and a water depth of 10 meters off Memory Rock, Bahamas, were correlated with 81 concurrent direct volume transport observations in the Straits of Florida. Daily-averaged sea level from either gauge on the Bahamian side of the Straits was poorly correlated with transport. Bottom pressure off Jupiter had a linear coefficient of determination ofr(2) = 0.93, and Miami sea level, when adjusted for weather effects, had r(2) = 0.74; the standard errors of estimating transports were +/- 1.2 x 10(6) and +/- 1.9 x 10(6) cubic meters per second, respectively. A linear multivariate regression, which combined bottom pressure, weather, and the submarine cable observations between Jupiter and the Bahamas, had r(2) = 0.94 with a standard error of estimating transport of +/- 1.1 x 10(6) cubic meters per second. These results suggest that a combination of easily obtained observations is sufficient to adequatelv monitor the daily volume transport fluctuations of the Florida Current. PMID:17742102

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

1985-01-18

240

Measurement of carrier transport and recombination parameter in heavily doped silicon  

NASA Technical Reports Server (NTRS)

The minority carrier transport and recombination parameters in heavily doped bulk silicon were measured. Both Si:P and Si:B with bulk dopings from 10 to the 17th and 10 to the 20th power/cu cm were studied. It is shown that three parameters characterize transport in bulk heavily doped Si: the minority carrier lifetime tau, the minority carrier mobility mu, and the equilibrium minority carrier density of n sub 0 and p sub 0 (in p-type and n-type Si respectively.) However, dc current-voltage measurements can never measure all three of these parameters, and some ac or time-transient experiment is required to obtain the values of these parameters as a function of dopant density. Using both dc electrical measurements on bipolar transitors with heavily doped base regions and transients optical measurements on heavily doped bulk and epitaxially grown samples, lifetime, mobility, and bandgap narrowing were measured as a function of both p and n type dopant densities. Best fits of minority carrier mobility, bandgap narrowing and lifetime as a function of doping density (in the heavily doped range) were constructed to allow accurate modeling of minority carrier transport in heavily doped Si.

Swanson, Richard M.

1986-01-01

241

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

NASA Technical Reports Server (NTRS)

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

Dixon, C. E.

1967-01-01

242

Application of Number Needed to Treat (NNT) as a Measure of Treatment Effect in Respiratory Medicine  

Microsoft Academic Search

measures that are objective, have clinical relevance, and are easily interpreted. Relative risk is often used to summarize treatment comparisons, but does not account for variations in baseline risk profiles and does not convey information on absolute sizes of treatment effects. Absolute risk reduction gives this information, but the data are dimensionless and abstract, and lack a direct connection with

Mario Cazzola

2006-01-01

243

Nusselt Number Measurements for Turbulent Rayleigh-Benard Convection Alexei Nikolaenko and Guenter Ahlers  

E-print Network

life which provokes fasci- nation for the nonspecialist. Last, but not least, it is one for this phenomenon [1­3,5­7]. Over time several models have been proposed to explain the depen- dence of N:78 109. Here we present new measurements for ' 4:4 which extend to the heretofore unexplored range near

Fygenson, Deborah Kuchnir

244

Measurement of the copy number of the master quorum-sensing regulator of a bacterial cell  

E-print Network

, Princeton, NJ 08544, USA, Howard Hughes Medical Institute, Chevy Chase, MD 20815, USA ABSTRACT Quorum is unchanged. Analyzing these changes statistically, we have determined that N = 80-135 dimers at low cell. By applying binomial distribution analysis to the partitioning errors of the proteins measured at cell

Ong, N. P.

245

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

246

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

Microsoft Academic Search

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

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

2004-01-01

247

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

248

84Unit Conversions Energy, Power, Flux Energy is measured in a number of ways depending on what property is being  

E-print Network

kilowatt- hour (1 kWh)? Problem 4 ­ How many ergs of energy are collected from a solar panel on a roof, if the sunlight provides a flux of 300 Joules/sec/meter 2 , the solar panels have an area of 27 square feet84Unit Conversions ­ Energy, Power, Flux Energy is measured in a number of ways depending on what

249

The Basic Reproductive Number of Ebola and the Effects of Public Health Measures: The Cases of Congo and Uganda  

Microsoft Academic Search

Despite improved control measures, Ebola remains a serious public health risk in African regions where recurrent outbreaks have been observed since the initial epidemic in 1976. Using epidemic modeling and data from two well-documented Ebola outbreaks (Congo 1995 and Uganda 2000), we estimate the number of secondary cases generated by an index case in the absence of control interventions ($R_0$).

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

2005-01-01

250

Effect of number of electrodes, electrode displacement, and RMS measurement noise on the localization accuracy of ECG inverse problem  

Microsoft Academic Search

The effect of the number of electrodes, electrode displacement and RMS measurement noise was evaluated using an anatomically-detailed computer model of the thorax as a volume conductor. The body surface potential distributions due to cardiac dipole sources were calculated by applying five different electrode montages: the eight electrodes representing the independent leads of the standard 12-lead electrocardiogram (ECG), a modified

H. G. Puurtinen; J. Hyttinen; P. Laarne; N. Takano; J. Malmivuo

2001-01-01

251

Characterization of the transport properties of channel delta-doped structures by light-modulated Shubnikov-de Haas measurements  

NASA Technical Reports Server (NTRS)

The transport properties of channel delta-doped quantum well structures were characterized by conventional Hall effect and light-modulated Shubnikov-de Haas (SdH) effect measurements. The large number of carriers that become available due to the delta-doping of the channel, leads to an apparent degeneracy in the well. As a result of this degeneracy, the carrier mobility remains constant as a function of temperature from 300 K down to 1.4 K. The large amount of impurity scattering, associated with the overlap of the charge carriers and the dopants, resulted in low carrier mobilities and restricted the observation of the oscillatory magneto-resistance used to characterize the two-dimensional electron gas (2DEG) by conventional SdH measurements. By light-modulating the carriers, we were able to observe the SdH oscillation at low magnetic fields, below 1.4 tesla, and derive a value for the quantum scattering time. Our results for the ratio of the transport and quantum scattering times are lower than those previously measured for similar structures using much higher magnetic fields.

Mena, R. A.; Schacham, S. E.; Haugland, E. J.; Alterovitz, S. A.; Young, P. G.; Bibyk, S. B.; Ringel, S. A.

1995-01-01

252

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

SciTech Connect

We measured spin-transport in nonferromagnetic (NM) metallic multilayers from the contribution to damping due to spin pumping from a ferromagnetic Co{sub 90}Fe{sub 10} thin film. The multilayer stack consisted of NM{sub 1}/NM{sub 2}/Co{sub 90}Fe{sub 10}(2 nm)/NM{sub 2}/NM{sub 3} with varying NM materials and thicknesses. Using conventional theory for one-dimensional diffusive spin transport in metals, we show that the effective damping due to spin pumping can be strongly affected by the spin transport properties of each NM in the multilayer, which permits the use of damping measurements to accurately determine the spin transport properties of the various NM layers in the full five-layer stack. We find that due to its high electrical resistivity, amorphous Ta is a poor spin conductor, in spite of a short spin-diffusion length of 1.0 nm, and that Pt is an excellent spin conductor by virtue of its low electrical resistivity and a spin diffusion length of only 0.5 nm. Spin Hall effect measurements may have underestimated the spin Hall angle in Pt by assuming a much longer spin diffusion length.

Boone, C. T.; Nembach, Hans T.; Shaw, Justin M.; Silva, T. J. [National Institute of Standards and Technology, Boulder, Colorado 80305 (United States)

2013-04-21

253

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

254

Precise measurement of particle-wall hydrodynamic interactions at low Reynolds number using laser interferometry  

NASA Astrophysics Data System (ADS)

The motion of a spherical particle (with radius 1 to 6 mm) in a viscous fluid is measured using laser interferometry. The typical sensitivity on the measured displacement of the sphere is of the order of 50 nm. The particle is moving on the axis of a closed cylinder. The hydrodynamic interactions between the particle and the walls of the cylinder are compared with the theoretical result of Sano (1987) valid for a very small sphere. The agreement is excellent for the smallest sphere used in the experiment. The experiment also agrees with the result from the theory of lubrication when the sphere is close to a plane end wall. The effect of the particle roughness appears at small distances. Laser interferometry appears to be a useful tool to study particle-wall hydrodynamic interactions when the geometry is cumbersome.

Lecoq, N.; Feuillebois, F.; Anthore, N.; Anthore, R.; Bostel, F.; Petipas, C.

1993-01-01

255

Precise measurement of particle-wall hydrodynamic interactions at low Reynolds number using laser interferometry  

NASA Astrophysics Data System (ADS)

The motion of a spherical particle (with radius 1 to 6 mm) in a viscous fluid is measured using laser interferometry. The typical sensitivity on the measured displacement of the sphere is of the order of 50 nm. The particle is moving on the axis of a closed cylinder. The hydrodynamic interactions between the particle and the walls of the cylinder are compared with the theoretical result of Sano [J. Phys. Soc. Jpn. 56, 2713 (1987)] valid for a very small sphere. The agreement is excellent for the smallest sphere used in the experiment. The experiment also agrees with the result from the theory of lubrication when the sphere is close to a plane end wall. The effect of the particle roughness appears at small distances. Laser interferometry appears as a useful tool to study particle-wall hydrodynamic interactions when the geometry is cumbersome.

Lecoq, N.; Feuillebois, F.; Anthore, N.; Anthore, R.; Bostel, F.; Petipas, C.

1993-01-01

256

Controlling and measuring quantum transport of heat in trapped-ion crystals  

E-print Network

Measuring heat flow through nanoscale systems poses formidable practical difficulties as there is no `ampere meter' for heat. We propose to overcome this problem by realizing heat transport through a chain of trapped ions. Laser cooling the chain edges to different temperatures induces a current of local vibrations (vibrons). We show how to efficiently control and measure this current, including fluctuations, by coupling vibrons to internal ion states. This demonstrates that ion crystals provide a suitable platform for studying quantum transport, e.g., through thermal analogues of quantum wires and quantum dots. Notably, ion crystals may give access to measurements of the elusive large fluctuations of bosonic currents and the onset of Fourier's law. These results are supported by numerical simulations for a realistic implementation with specific ions and system parameters.

A. Bermudez; M. Bruderer; M. B. Plenio

2013-03-29

257

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

NASA Technical Reports Server (NTRS)

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.

1992-01-01

258

Measurement of three-dimensional coherent fluid structure in high Reynolds number turbulent boundary layers  

E-print Network

- tion approach [Scarano & Riethmuller, 2000; Scarano, 2002], the normalised median outlier test [Westerweel & Scarano, 2005], lessons regarding the accu- racy of different interrogation techniques [Piirto et al., 2005] and the selection of optimal sub... measurement technique must have a larger ’dynamic range’ to fully resolve the flow. Tomographic PIV is currently limited in spatial dy- namic range (which is also linked to the spatial and temporal resolution) due to a high degree of noise. Results also...

Clark, Thomas Henry

2012-07-03

259

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. PMID:23964256

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

2013-01-01

260

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

E-print Network

the existence of mass transfer in the direction of propagation of nonlinear traveling waves (TW) as well that the two previously observed oscillatory states differ in mass transfer. In linear counterpropagating waves. The relevant control parameters are then the Rayleigh number, which is the nondimensional temperature dif

Moses, Elisha

261

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

262

WIND measurements of proton and alpha particle flow and number density  

NASA Technical Reports Server (NTRS)

We propose to review measurements of the solar wind proton and alpha particle flow velocities and densities made since launch with the WIND SWE instrument. The SWE Faraday cup ion sensors are designed to be able to determine accurately flow vector directions, and thus can be used to detect proton-alpha particle differential flow. Instances of differential flow, and the solar wind features with which they are associated will be discussed. Additionally, the variability of the percentage of alpha particles as a fraction of the total solar wind ion density will be presented.

Steinberg, J. T.; Lazarus, A. J.; Ogilvie, J. T.; Lepping, R.; Byrnes, J.; Chornay, D.; Keller, J.; Torbert, R. B.; Bodet, D.; Needell, G. J.

1995-01-01

263

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

264

Phase Averaged Measurements of the Coherent Structure of a Mach Number 0.6 Jet. M.S. Thesis  

NASA Technical Reports Server (NTRS)

The existence of a large scale structure in a Mach number 0.6, axisymmetric jet of cold air was proven. In order to further characterize the coherent structure, phase averaged measurements of the axial mass velocity, radial velocity, and the product of the two were made. These measurements yield information about the percent of the total fluctuations contained in the coherent structure. These measured values were compared to the total fluctuation levels for each quantity and the result expressed as a percent of the total fluctuation level contained in the organized structure at a given frequency. These measurements were performed for five frequencies (St=0.16, 0.32, 0.474, 0.95, and 1.26). All of the phase averaged measurements required that the jet be artificially excited.

Emami, S.

1983-01-01

265

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

SciTech Connect

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

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

1984-01-01

266

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

SciTech Connect

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

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

1984-01-01

267

Cryogenic wind tunnel technology. A way to measurement at higher Reynolds numbers  

NASA Technical Reports Server (NTRS)

The goals, design, problems, and value of cryogenic transonic wind tunnels being developed in Europe are discussed. The disadvantages inherent in low-Reynolds-number (Re) wind tunnel simulations of aircraft flight at high Re are reviewed, and the cryogenic tunnel is shown to be the most practical method to achieve high Re. The design proposed for the European Transonic Wind tunnel (ETW) is presented: parameters include cross section. DISPLAY 83A46484/2 = 4 sq m, operating pressure = 5 bar, temperature = 110-120 K, maximum Re = 40 x 10 to the 6th, liquid N2 consumption = 40,000 metric tons/year, and power = 39,5 MW. The smaller Cologne subsonic tunnel being adapted to cryogenic use for preliminary studies is described. Problems of configuration, materials, and liquid N2 evaporation and handling and the research underway to solve them are outlined. The benefits to be gained by the construction of these costly installations are seen more in applied aerodynamics than in basic research in fluid physics. The need for parallel development of both high Re tunnels and computers capable of performing high-Re numerical analysis is stressed.

Beck, J. W.

1984-01-01

268

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

269

PIV Velocity Measurements from Rayleigh-Taylor Mixing at Small Atwood Number  

NASA Astrophysics Data System (ADS)

Velocity measurements with a PIV system were made from a Rayleigh-Taylor mix layer which is statistically stationary in an Eulerian frame. The mixing layer was comprised of two streams of water with the cold water above the hot, and the mixing layer evolving downstream from a splitter plate. Two 120mJ Nd: YAG lasers illuminated ~ 10 micron hollow silvered glass beads of density ~ 1.1 gm/cm^3 with a light sheet parallel to the stream velocity. Images of the particles were acquired through a CCD camera at a rate of 30 frames per second, and displacement vectors were determined with a particle tracking technique. The entire mixing channel was mapped with the velocity components parallel and normal to the pressure gradient, and velocity fluctuation correlations were made from an ensemble of 1200 images from each experiment.

Wilson, Peter; Andrews, Malcolm

2000-11-01

270

Boundary layer, skin friction, and boattail pressure measurements from the YF-12 airplane at Mach numbers up to 3  

NASA Technical Reports Server (NTRS)

In-flight measurements of boundary layer and skin friction data were made on YF-12 airplanes for Mach numbers between 2.0 and 3.0. Boattail pressures were also obtained for Mach numbers between 0.7 and 3.0 with Reynolds numbers up to four hundred million. Boundary layer data measured along the lower fuselage centerline indicate local displacement and momentum thicknesses can be much larger than predicted. Skin friction coefficients measured at two of five lower fuselage stations were significantly less than predicted by flat plate theory. The presence of large differences between measured boattail pressure drag and values calculated by a potential flow solution indicates the presence of vortex effects on the upper boattail surface. At both subsonic and supersonic speeds, pressure drag on the longer of two boattail configurations was equal to or less than the pressure drag on the shorter configuration. At subsonic and transonic speeds, the difference in the drag coefficient was on the order of 0.0008 to 0.0010. In the supersonic cruise range, the difference in the drag coefficient was on the order of 0.002. Boattail drag coefficients are based on wing reference area.

Fisher, D. F.

1978-01-01

271

Determination of car on-road black carbon and particle number emission factors and comparison between mobile and stationary measurements  

NASA Astrophysics Data System (ADS)

We have used two methods for measuring emission factors (EF) in real driving conditions on five cars in a controlled environment: the stationary method, where the investigated vehicle drives by the stationary measurement platform and the composition of the plume is measured; and the chasing method, where a mobile measurement platform drives behind the investigated vehicle. We measured EF of black carbon and particle number concentration. The stationary method was tested for repeatability at different speeds and on a slope. The chasing method was tested on a test track and compared to the portable emission measurement system. We further developed the data processing algorithm for both methods, trying to improve consistency, determine the plume duration, limit the background influence and facilitate automatic processing of measurements. The comparison of emission factors determined by the two methods showed good agreement. EFs of a single car measured with either method have a specific distribution with a characteristic value and a long tail of super emissions. Measuring EFs at different speeds or slopes did not significantly influence the EFs of different cars, hence we propose a new description of vehicle emissions that is not related to kinematic or engine parameters, rather we describe the vehicle EF with a characteristic value and a "super emission" tail.

Ježek, I.; Drinovec, L.; Ferrero, L.; Carriero, M.; Mo?nik, G.

2014-06-01

272

Evolution of particle number distribution near roadways—Part I: analysis of aerosol dynamics and its implications for engine emission measurement  

Microsoft Academic Search

Studies have suggested that aerosol number concentrations may be better correlated to health effects than mass concentrations so that the high particle number concentrations in the vicinity of freeways raise concerns regarding adverse health effects on people living there. Thus, it is important to understand how particles transport and transform near roadways for regulatory purposes. Driven by different mixing forces,

K. Max Zhanga; Anthony S. Wexler

2004-01-01

273

High-Reynolds Number Active Blowing Semi-Span Force Measurement System Development  

NASA Technical Reports Server (NTRS)

Recent wind-tunnel tests at the NASA Langley Research Center National Transonic Facility utilized high-pressure bellows to route air to the model for evaluating aircraft circulation control. The introduction of these bellows within the Sidewall Model Support System significantly impacted the performance of the external sidewall mounted semi-span balance. As a result of this impact on the semi-span balance measurement performance, it became apparent that a new capability needed to be built into the National Transonic Facility s infrastructure to allow for performing pressure tare calibrations on the balance in order to properly characterize its performance under the influence of static bellows pressure tare loads and bellows thermal effects. The objective of this study was to design both mechanical calibration hardware and an experimental calibration design that can be employed at the facility in order to efficiently and precisely perform the necessary loadings in order to characterize the semi-span balance under the influence of multiple calibration factors (balance forces/moments and bellows pressure/temperature). Using statistical design of experiments, an experimental design was developed allowing for strategically characterizing the behavior of the semi-span balance for use in circulation control and propulsion-type flow control testing at the National Transonic Facility.

Lynn, Keith C.; Rhew, Ray D.; Acheson, Michael J.; Jones, Gregory S.; Milholen, William E.; Goodliff, Scott L.

2012-01-01

274

Modification of DNA towards high conductance and transport measurements with mechanically controllable break junction electrodes  

NASA Astrophysics Data System (ADS)

The DNA molecule is proposed to be used as building block for molecular electronic devices by virtue of its unique recognition and self-assembling properties. However, electron transport properties of DNA are still not well established mainly because poor binding between DNA and gold electrodes. Here, we synthesized new DNA samples with terminal bases modified with a thiol group on its C5 atom and protected with Me3Si for better binding with gold electrodes and better conductivity because of better electron overlap. Its transport properties were measured with mechanically controlled break junction. Conductance with a current of 700 nA in 0.25V were obtained, which is higher than most of the former reports. We also measured conductance through DNA G-quadruple instead of double-stranded structure., which shows a more stable conductance when the distance between electrodes reversibly varied over a several nm.

Liu, Shoupeng; Bornemann, Benjamin; Weisbrod, Samuel; Tang, Zhuo; Marx, Andreas; Erbe, Artur; Scheer, Elke

2011-03-01

275

Full-Scale Measurements of Motions and Stresses on a 1600-t Jacket During Transportation  

Microsoft Academic Search

This paper presents the results of full scale measurements performed on a 1600-t jacket during its transportation on board a 7500-t towed barge along the Northeast coast of Brazil showing a comprehensive set of motion variables, forces and stresses on sea-fastening system. The response of kinematic variables and forces on the sea-fastening elements due to the wave action are correlated

C. P. Pesce; Danton Nunes; Mario Rubio; Toshi Tachibana; Arney Marques

1983-01-01

276

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

277

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

Microsoft Academic Search

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

Chris H. Hugenholtz; Thomas E. Barchyn

2011-01-01

278

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

279

Two-path transport measurements with bias dependence on a triple quantum dot  

SciTech Connect

We present transport measurements on a lateral triple quantum dot with a star-like geometry and one lead attached to each dot. The system is studied in a regime close to established quadruple points, where all three dots are in resonance. The specific sample structure allows us to apply two different bias voltages to the two source leads and thus to study the influence between the paths with serial double dots.

Kotzian, M.; Rogge, M. C.; Haug, R. J. [Institut für Festkörperphysik, Leibniz Universität Hannover, Appelstr. 2, 30167 Hannover (Germany)

2013-12-04

280

Measurement and Improved Understanding of Vertical Transport and the Evaluation of these Processes in Mesoscale Models  

SciTech Connect

The NCAR effort is primarily focused on the analysis of a diverse suite of measurements taken at the southern end of the Salt Lake City Valley within the Jordan Narrows. These measurements include wind profiler, surface, lidar, radiosonde, multi-layered tether-sonde and sodar measurements. We are also collaborating with other VTMX investigators through linking our measurements within the Jordan Narrows with their investigations. The instrumentation was provided to interested VTMX investigators and was used extensively. Thus the NCAR data set played a large role in the results of the overall experiment. Our work under this proposal includes analysis of the observations, mesoscale modeling efforts in support of our VTMX analysis and general instrumentation development aimed at improving the measurement of vertical transport and mixing under stable conditions. This report is subdivided by research objectives.

David Parsons, James Pinto, William Brown, Stephen Cohn, Bruce Morley

2007-02-13

281

Turbulence measurement in a reacting and non-reacting shear layer at a high subsonic Mach number  

NASA Technical Reports Server (NTRS)

The results of two component velocity and turbulence measurements are presented which were obtained on a planar reacting shear layer burning hydrogen. Quantitative LDV and temperature measurements are presented with and without chemical reaction within the shear layer at a velocity ratio of 0.34 and a high speed Mach number of 0.7. The comparison showed that the reacting shear layer grew faster than that without reaction. Using a reduced width coordinate, the reacting and non-reacting profiles were very similar. The peak turbulence for both cases was 20 percent.

Chang, C. T.; Marek, C. J.; Wey, C.; Jones, R. A.; Smith, M. J.

1993-01-01

282

Mobile measurements of aerosol number and volume size distributions in an Alpine valley: Influence of traffic versus wood burning  

NASA Astrophysics Data System (ADS)

The spatial variability of highly time resolved size distributions was investigated in a narrow valley which provides the opportunity to study the impact of different sources on ambient particle concentrations during summer and winter time. The measurements were performed with a Fast Mobility Particle Sizer (FMPS) from TSI, Inc. on a mobile laboratory in Southern Switzerland. The results indicate enhanced number concentrations (between 150 000 and 500 000 cm -3) along the busy highway A2 which is the main transit route through the Swiss Alps connecting the northern and southern part of Switzerland. Especially the nanoparticles with diameters lower than 30 nm showed strongly increased number concentrations on the highway both in summer and winter. In winter time, high aerosol volume concentrations (PM 0.3) were found in villages where wood burning is often used for heating purposes. Both traffic and wood burning were found to be important sources for particulate mass which accumulates during temperature inversions in winter time. Traffic was the dominant and wood burning a minor source for the nanoparticle number concentration. This is important regarding health impacts and its attribution to different sources because wood burning might contribute most to particulate mass whereas at the same time and place traffic contributes most to particulate number. In addition, during summer time volatility measurements were performed with the FMPS showing that the nucleation mode prevalently seen on the highway was removed by more than 95% by thermal treatment.

Weimer, S.; Mohr, C.; Richter, R.; Keller, J.; Mohr, M.; Prévôt, A. S. H.; Baltensperger, U.

283

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

284

Cosmic-ray abundances of elements with atomic number 26 less than or equal to 40 measured on HEAO 3  

NASA Technical Reports Server (NTRS)

Individual elements in the cosmic radiation of even atomic number (Z) in the interval 26-40 have been resolved and their relative abundances measured. The results are inconsistent with a cosmic-ray source whose composition in this charge interval is dominated by r-process nucleosynthesis. The ratios of cosmic-ray source abundances to solar system abundances in this interval follow the same general correlation with first ionization potential as for the lighter elements, although there are deviations in detail.

Binns, W. R.; Fickle, R. K.; Waddington, C. J.; Garrard, T. L.; Stone, E. C.; Israel, M. H.; Klarmann, J.

1981-01-01

285

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

Microsoft Academic Search

Despite improved control measures, Ebola remains a serious public health risk in African regions where recurrent outbreaks have been observed since the initial epidemic in 1976: Using epidemic modeling and data from two well-documented Ebola outbreaks (Congo 1995 and Uganda 2000), we estimate the number of secondary cases generated by an index case in the absence of control interventions ðR0Þ:

G. Chowell; N. W. Hengartnerb; C. Castillo-Chavez; P. W. Fenimorea

286

Dose and linear energy transfer spectral measurements for the supersonic transport program  

NASA Technical Reports Server (NTRS)

The purpose of the package, called the high altitude radiation instrumentation system (HARIS), is to measure the radiation hazard to supersonic transport passengers from solar and galactic cosmic rays. The HARIS includes gaseous linear energy transfer spectrometer, a tissue equivalent ionization chamber, and a geiger meuller tube. The HARIS is flown on RB-57F aircraft at 60,000 feet. Data from the HARIS are reduced to give rad and rem dose rates measured by the package during the flights. Results presented include ambient data obtained on background flights, altitude comparison data, and solar flare data.

Philbrick, R. B.

1972-01-01

287

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

DOEpatents

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

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

1999-01-01

288

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. PMID:15717054

Bickel, Ulrich

2005-01-01

289

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

PubMed Central

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

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

2006-01-01

290

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

291

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

PubMed

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

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

2014-02-01

292

Evolution of particle number distribution near roadways—Part I: analysis of aerosol dynamics and its implications for engine emission measurement  

NASA Astrophysics Data System (ADS)

Studies have suggested that aerosol number concentrations may be better correlated to health effects than mass concentrations so that the high particle number concentrations in the vicinity of freeways raise concerns regarding adverse health effects on people living there. Thus, it is important to understand how particles transport and transform near roadways for regulatory purposes. Driven by different mixing forces, exhaust dilution near roadways usually experiences two distinct dilution stages after being emitted—'tailpipe-to-road' and 'road-to-ambient'. The first stage dilution is induced by traffic-generated turbulence and the dilution ratio usually reaches up to about 1000:1 in around 1-3 s; the second stage dilution is mainly dependent on atmospheric turbulence, the additional dilution ratio is usually about 10:1, and the process usually lasts around 3-10 min. The aerosol dynamical processes, such as nucleation, condensation and coagulation were qualitatively investigated in the first stage. For the second stage, condensation and dilution were the major mechanisms in altering aerosol size distribution, while coagulation and deposition play minor roles. Based on the analysis, a modeling structure for a mechanistic roadway air quality model is proposed. Our study also indicates that in order to simulate the first stage, 'in-tailpipe' measurement of aerosol size distribution and condensable material concentrations in their original phase states is necessary. The implications for dilution tunnel design are discussed.

Zhang, K. Max; Wexler, Anthony S.

293

Describing and compensating gas transport dynamics for accurate instantaneous emission measurement  

NASA Astrophysics Data System (ADS)

Instantaneous emission measurements on chassis dynamometers and engine test benches are becoming increasingly usual for car-makers and for environmental emission factor measurement and calculation, since much more information about the formation conditions can be extracted than from the regulated bag measurements (integral values). The common exhaust gas analysers for the "regulated pollutants" (carbon monoxide, total hydrocarbons, nitrogen oxide, carbon dioxide) allow measurement at a rate of one to ten samples per second. This gives the impression of having after-the-catalyst emission information with that chronological precision. It has been shown in recent years, however, that beside the reaction time of the analysers, the dynamics of gas transport in both the exhaust system of the car and the measurement system last significantly longer than 1 s. This paper focuses on the compensation of all these dynamics convoluting the emission signals. Most analysers show linear and time-invariant reaction dynamics. Transport dynamics can basically be split into two phenomena: a pure time delay accounting for the transport of the gas downstream and a dynamic signal deformation since the gas is mixed by turbulence along the way. This causes emission peaks to occur which are smaller in height and longer in time at the sensors than they are after the catalyst. These dynamics can be modelled using differential equations. Both mixing dynamics and time delay are constant for modelling a raw gas analyser system, since the flow in that system is constant. In the exhaust system of the car, however, the parameters depend on the exhaust volume flow. For gasoline cars, the variation in overall transport time may be more than 6 s. It is shown in this paper how all these processes can be described by invertible mathematical models with the focus on the more complex case of the car's exhaust system. Inversion means that the sharp emission signal at the catalyst out location can be reconstructed from a flattened emission signal at the sensor. In this modelling, special focus is put on finding an easy parameterisation for different cars. The process of finding these compensators consists of first describing the process by differential equations of appropriate order and parameterising them, resulting in low pass systems. The following step of inverting these systems results automatically in high pass systems. These kinds of systems, however, amplify measurement noise, thus they need signal filters to smooth their output.

Weilenmann, Martin; Soltic, Patrik; Ajtay, Delia

294

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

295

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

296

Measurements of electron transport in foils irradiated with a picosecond time scale laser pulse.  

PubMed

The heating of solid foils by a picosecond time scale laser pulse has been studied by using x-ray emission spectroscopy. The target material was plastic foil with a buried layer of a spectroscopic tracer material. The laser pulse length was either 0.5 or 2 ps, which resulted in a laser irradiance that varied over the range 10(16)-10(19) W/cm(2). Time-resolved measurements of the buried layer emission spectra using an ultrafast x-ray streak camera were used to infer the density and temperature conditions as a function of laser parameters and depth of the buried layer. Comparison of the data to different models of electron transport showed that they are consistent with a model of electron transport that predicts the bulk of the target heating is due to return currents. PMID:21635097

Brown, C R D; Hoarty, D J; James, S F; Swatton, D; Hughes, S J; Morton, J W; Guymer, T M; Hill, M P; Chapman, D A; Andrew, J E; Comley, A J; Shepherd, R; Dunn, J; Chen, H; Schneider, M; Brown, G; Beiersdorfer, P; Emig, J

2011-05-01

297

Radicals and Reservoirs in the GMI Chemistry and Transport Model: Comparison to Measurements  

NASA Technical Reports Server (NTRS)

We have used a three-dimensional chemistry and transport model (CTM), developed under the Global Modeling Initiative (GMI), to carry out two simulations of the composition of the stratosphere under changing halogen loading for 1995 through 2030. The two simulations differ only in that one uses meteorological fields from a general circulation model while the other uses meteorological fields from a data assimilation system. A single year's winds and temperatures are repeated for each 36-year simulation. We compare results from these two simulations with an extensive collection of data from satellite and ground-based measurements for 1993-2000. Comparisons of simulated fields with observations of radical and reservoir species for some of the major ozone-destroying compounds are of similar quality for both simulations. Differences in the upper stratosphere, caused by transport of total reactive nitrogen and methane, impact the balance among the ozone loss processes and the sensitivity of the two simulations to the change in composition.

Douglass, Anne R.; Stolarski, Richard S.; Strahan, Susan E.; Connell, Peter S.

2004-01-01

298

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

NASA Astrophysics Data System (ADS)

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 1016-1019W/cm2. 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.; Shepherd, R.; Dunn, J.; Chen, H.; Schneider, M.; Brown, G.; Beiersdorfer, P.; Emig, J.

2011-05-01

299

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

PubMed

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. PMID:18315313

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

2008-02-01

300

Analytical interpretation of nondiffusive phonon transport in thermoreflectance thermal conductivity measurements  

NASA Astrophysics Data System (ADS)

We derive an analytical solution to the Boltzmann transport equation (BTE) to relate nondiffusive thermal conductivity measurements by thermoreflectance techniques to the bulk thermal conductivity accumulation function, which quantifies cumulative contributions to thermal conductivity from different mean free path energy carriers (here, phonons). Our solution incorporates two experimentally defined length scales: thermal penetration depth and heating laser spot radius. We identify two thermal resistances based on the predicted spatial temperature and heat flux profiles. The first resistance is associated with the interaction between energy carriers and the surface of the solution domain. The second resistance accounts for transport of energy carriers through the solution domain and is affected by the experimentally defined length scales. Comparison of the BTE result with that from conventional heat diffusion theory enables a mapping of mean-free-path-specific contributions to the measured thermal conductivity based on the experimental length scales. In general, the measured thermal conductivity will be influenced by the smaller of the two length scales and the surface properties of the system. The result is used to compare nondiffusive thermal conductivity measurements of silicon with first-principles-based calculations of its thermal conductivity accumulation function.

Regner, K. T.; McGaughey, A. J. H.; Malen, J. A.

2014-08-01

301

Membrane transport mechanisms probed by capacitance measurements with megahertz voltage clamp.  

PubMed Central

We have used capacitance measurements with a 1-microsecond voltage clamp technique to probe electrogenic ion-transporter interactions in giant excised membrane patches. The hydrophobic ion dipicrylamine was used to test model predictions for a simple charge-moving reaction. The voltage and frequency dependencies of the apparent dipicrylamine-induced capacitance, monitored by 1-mV sinusoidal perturbations, correspond to single charges moving across 76% of the membrane field at a rate of 9500 s-1 at 0 mV. For the cardiac Na,K pump, the combined presence of cytoplasmic ATP and sodium induces an increase of apparent membrane capacitance which requires the presence of extracellular sodium. The dependencies of capacitance changes on frequency, voltage, ATP, and sodium verify that phosphorylation enables a slow, 300- to 900-s-1, pump transition (the E1-E2 conformational change), which in turn enables fast, electrogenic, extracellular sodium binding reactions. For the GAT1 (gamma-aminobutyric acid,Na,Cl) cotransporter, expressed in Xenopus oocyte membrane, we find that chloride binding from the cytoplasmic side, and probably sodium binding from the extracellular side, results in a decrease of membrane capacitance monitored with 1- to 50-kHz perturbation frequencies. Evidently, ion binding by the GAT1 transporter suppresses an intrinsic fast charge movement which may originate from a mobility of charged residues of the transporter binding sites. The results demonstrate that fast capacitance measurements can provide new insight into electrogenic processes closely associated with ion binding by membrane transporters. Images Fig. 2 Fig. 3 Fig. 4 PMID:7479969

Lu, C C; Kabakov, A; Markin, V S; Mager, S; Frazier, G A; Hilgemann, D W

1995-01-01

302

Controlling and Measuring Quantum Transport of Heat in Trapped-Ion Crystals  

NASA Astrophysics Data System (ADS)

Measuring heat flow through nanoscale devices poses formidable practical difficulties as there is no “ampere meter” for heat. We propose to overcome this problem in a chain of trapped ions, where laser cooling the chain edges to different temperatures induces a heat current of local vibrations (vibrons). We show how to efficiently control and measure this current, including fluctuations, by coupling vibrons to internal ion states. This demonstrates that ion crystals provide an ideal platform for studying quantum transport, e.g., through thermal analogues of quantum wires and quantum dots. Notably, ion crystals may give access to measurements of the elusive bosonic fluctuations in heat currents and the onset of Fourier’s law. Our results are strongly supported by numerical simulations for a realistic implementation with specific ions and system parameters.

Bermudez, A.; Bruderer, M.; Plenio, M. B.

2013-07-01

303

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

304

Electron density and transport in top-gated graphene nanoribbon devices: First-principles Green function algorithms for systems containing a large number of atoms  

NASA Astrophysics Data System (ADS)

The recent fabrication of graphene nanoribbon (GNR) field-effect transistors poses a challenge for first-principles modeling of carbon nanoelectronics due to many thousand atoms present in the device. The state of the art quantum transport algorithms, based on the nonequilibrium Green function formalism combined with the density-functional theory (NEGF-DFT), were originally developed to calculate self-consistent electron density in equilibrium and at finite bias voltage (as a prerequisite to obtain conductance or current-voltage characteristics, respectively) for small molecules attached to metallic electrodes where only a few hundred atoms are typically simulated. Here we introduce combination of two numerically efficient algorithms which make it possible to extend the NEGF-DFT framework to device simulations involving large number of atoms. Our first algorithm offers an alternative to the usual evaluation of the equilibrium part of electron density via numerical contour integration of the retarded Green function in the upper complex half-plane. It is based on the replacement of the Fermi function f(E) with an analytic function f˜(E) coinciding with f(E) inside the integration range along the real axis, but decaying exponentially in the upper complex half-plane. Although f˜(E) has infinite number of poles, whose positions and residues are determined analytically, only a finite number of those poles have non-negligible residues. We also discuss how this algorithm can be extended to compute the nonequilibrium contribution to electron density, thereby evading cumbersome real-axis integration (within the bias voltage window) of NEGFs which is very difficult to converge for systems with large number of atoms while maintaining current conservation. Our second algorithm combines the recursive formulas with the geometrical partitioning of an arbitrary multiterminal device into nonuniform segments in order to reduce the computational complexity of the retarded Green function evaluation by extracting only its submatrices required for electron density and transmission function. We illustrate fusion of these two algorithms into the NEGF-DFT-type code by computing charge transfer, charge redistribution and conductance in zigzag- GNR?variable -width-armchair- GNR?zigzag -GNR two-terminal device covered with a gate electrode made of graphene layer as well. The total number of carbon and edge-passivating hydrogen atoms within the simulated central region of this device is ?7000 . Our self-consistent modeling of the gate voltage effect suggests that rather large gate voltage ?3eV might be required to shift the band gap of the proposed AGNR interconnect and switch the transport from insulating into the regime of a single open conducting channel.

Areshkin, Denis A.; Nikoli?, Branislav K.

2010-04-01

305

Removing traffic emissions from CO2 time series measured at a tall tower using mobile measurements and transport modeling  

NASA Astrophysics Data System (ADS)

In recent years, measurements of atmospheric carbon dioxide with high precision and accuracy have become increasingly important for climate change research, in particular to inform terrestrial biosphere models. Anthropogenic carbon dioxide emissions from fossil fuel burning have long been recognized to contribute a significant portion of the carbon dioxide in the atmosphere. Here, we present an approach to remove the traffic related carbon dioxide emissions from mole fractions measured at a tall tower by using the corresponding carbon monoxide measurements in combination with footprint analyses and transport modeling. This technique improves the suitability of the CO2 data to be used in inverse modeling approaches of atmosphere-biosphere exchange that do not account for non-biotic portions of CO2. In our study region in Oregon, road traffic emissions are the biggest source of anthropogenic carbon dioxide and carbon monoxide. A three-day mobile campaign covering 1700 km of roads in northwestern Oregon was performed during summer of 2012 using a laser-based Cavity Ring-Down Spectrometer. The mobile measurements incorporated different roads including main highways, urban streets, and back-roads, largely within the typical footprint of a tall CO/CO2 observation tower in Oregon's Willamette Valley. For the first time, traffic related CO:CO2 emission ratios were measured directly at the sources during an on-road campaign under a variety of different driving conditions. An average emission ratio of 7.43 (±1.80) ppb CO per ppm CO2 was obtained for the study region and applied to separate the traffic related portion of CO2 from the mole fraction time series. The road traffic related portion of the CO2 mole fractions measured at the tower site reached maximum values ranging from 9.8 to 12 ppm, depending on the height above the surface, during summer 2012.

Schmidt, Andres; Rella, Chris W.; Göckede, Mathias; Hanson, Chad; Yang, Zhenlin; Law, Beverly E.

2014-11-01

306

Berekening van Atmosferisch Transport van Organische Stoffen: Methoden en Achtergronden (Measurement of Atmospheric Transport of Organic Compounds: Methods and Background).  

National Technical Information Service (NTIS)

Emission of pollutants, followed by their atmospheric transport and deposition, is one of the various routes which lead to exposure of man and the environment. Ambient concentration levels and deposition loads can be predicted by the use of atmospheric tr...

H. Noordijk, F. A. A. M. de Leeuw

1991-01-01

307

A Transport Analysis of In Situ Airborne Ozone Measurements from the 2011 DISCOVER-AQ Campaign  

NASA Astrophysics Data System (ADS)

Baltimore and Washington are currently designated as nonattainment areas with respect to the 2008 EPA National Ambient Air Quality Standard (NAAQS) for 8-hour Ozone (O3). Tropospheric O3 is the dominant component of summertime photochemical smog, and at high levels, has deleterious effects on human health, ecosystems, and materials. The University of Maryland (UMD) Regional Atmospheric Measurement Modeling and Prediction Program (RAMMPP) strives to improve understanding of air quality in the Mid-Atlantic States and to elucidate contributions of pollutants such as O3 from regional transport versus local sources through a combination of modeling and in situ measurements. The NASA Deriving Information on Surface Conditions from Column and Vertically Resolved Observations Relevant to Air Quality (DISCOVER-AQ) project investigates the connection between column measurements and surface conditions to explore the potential of remote sensing observations in diagnosing air quality at ground level where pollutants can affect human health. During the 2011 DISCOVER-AQ field campaign, in situ airborne measurements of trace gases and aerosols were performed along the Interstate 95 corridor between Baltimore and Washington from the NASA P3B aircraft. To augment this data and provide regional context, measurements of trace gases and aerosols were also performed by the RAMMPP Cessna 402B aircraft over nearby airports in Maryland and Virginia. This work presents an analysis of O3 measurements made by the Ultraviolet (UV) Photometric Ambient O3 Analyzer on the RAMMPP Cessna 402B and by the NCAR 4-Channel Chemiluminescence instrument on the NASA P3B. In this analysis, spatial and temporal patterns of O3 data are examined within the context of forward and backward trajectories calculated from 12-km North American Mesoscale (NAM) meteorological data using the NOAA Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) Model and from a high resolution Weather Research and Forecasting (WRF) model simulation in order to discern O3 resulting from regional transport versus O3 generated photochemically from local pollution sources. During the summer 2011 DISCOVER-AQ field campaign, both aircraft flew on eight overlapping dates. From the spirals performed on those flight days, over 15 cases have been identified where measurements of O3 were performed with one aircraft upwind of the other, based on forward and backward trajectory data. Analysis of these cases indicates that regional transport of O3 is enhanced up to 10% on average by local photochemical O3 production.

Arkinson, H. L.; Brent, L. C.; He, H.; Loughner, C.; Stehr, J. W.; Weinheimer, A. J.; Dickerson, R. R.

2013-12-01

308

Fringe pattern photobleaching, a new method for the measurement of transport coefficients of biological macromolecules.  

PubMed Central

The conventional method of studying mass transport in membranes by spot photobleaching and then following the recovery of fluorescence has disadvantages. Among them, the need for a high density of fluorescent molecules, the measurement of the beam profile, and a knowledge of the photobleaching processes are of a crucial importance. The application of a planar fringe pattern of light both for the bleaching and the monitoring of the fluorescent molecules solves these three major difficulties. Brownian diffusion coefficients and flow velocities can be measured independently and are averaged over the whole fringe pattern volume. These transport coefficients are explored over the wide range of experimentally accessible distances (from an interfringe spacing 0.5-50 micron). The quantification of the mobile and immobile components is further simplified by scanning the fringe pattern and detecting only a modulated fluorescence recovery signal. The fringe pattern photobleaching method is particularly adapted to the measurements of diffusion coefficients and flow velocity of membrane components, as well as of cytoplasmic proteins. The theoretical results and the test experiments with fluorescent bovine serum albumin are described. PMID:6821332

Davoust, J; Devaux, P F; Leger, L

1982-01-01

309

A nu-space for ICS: characterization and application to measure protein transport in live cells  

PubMed Central

We introduce a new generalized theoretical framework for image correlation spectroscopy (ICS). Using this framework, we extend the ICS method in time-frequency (?, nu) space to map molecular flow of fluorescently tagged proteins in individual living cells. Even in the presence of a dominant immobile population of fluorescent molecules, nu-space ICS (nICS) provides an unbiased velocity measurement, as well as the diffusion coefficient of the flow, without requiring filtering. We also develop and characterize a tunable frequency-filter for STICS that allows quantification of the density, the diffusion coefficient and the velocity of biased diffusion. We show that the techniques are accurate over a wide range of parameter space in computer simulation. We then characterize the retrograde flow of adhesion proteins (?6- and ?L?2-GFP integrins and mCherry-paxillin) in CHO.B2 cells plated on laminin and ICAM ligands respectively. STICS with a tunable frequency filter, in conjunction with nICS, measures two new transport parameters, the density and transport bias coefficient (a measure of the diffusive character of a flow/biased diffusion), showing that molecular flow in this cell system has a significant diffusive component. Our results suggest that the integrinligand interaction, along with the internal myosin-motor generated force, varies for different integrin-ligand pairs, consistent with previous results. PMID:24223019

Potvin-Trottier, Laurent; Chen, Lingfeng; Horwitz, Alan Rick; Wiseman, Paul W.

2013-01-01

310

Photocharge transport and recombination measurements in amorphous silicon films and solar cells by photoconductive frequency mixing: Annual subcontract report, 20 April 1998--19 April 1999  

SciTech Connect

In the present phase of the program, the transport parameters of a number of amorphous semiconductors prepared by a number of techniques were determined by the photoconductive frequency mixing technique. This technique enabled the authors to determine the drift mobility, md, and the photomixing lifetime, t. The technique is based on the idea of heterodyne detection for photoconductors. When two similarly polarized monochromatic optical beams of slightly different frequencies are incident upon a photoconductor, the generation rate of electron-hole pairs will produce a photocurrent, when a dc-bias is applied, which will contain components resulting from the square of the sum of the individual incident fields. Consequently, a photocurrent will be produced, which will consist of a direct current and a microwave current corresponding to the beat frequency. These two currents allow a separate determination of the drift mobility and the photomixing lifetime of the photogenerated carriers. In the present work, the longitudinal modes of a He-Ne laser were employed to generate a beat frequency of 252 MHz; all the measurements were performed at this frequency for the data indicated in the accompanying figures. The following topics were explored: Measurements of the charge transport parameters of homogeneous a-SiGe:H alloys produced by NREL employing the hot-wire technique; The change in the charge transport parameters in the transition from hydrogenated amorphous silicon to microcrystalline silicon for material produced by NREL and MVSystems; The improvement in instrumentation of the photomixing measurements; Measurements of the hydrostatic dependency of the transport parameters of amorphous silicon; and Preliminary photomixing measurements on p-i-n devices.

Braunstein, R.; Kattwinkel, A.; Liebe, J.; Sun, G.

2000-02-28

311

Measurement of Temperature, Density, and Particle Transport with Localized Dopants in Wire-Array Z Pinches  

NASA Astrophysics Data System (ADS)

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

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

2008-03-01

312

Modelling of turbulent impurity transport in fusion edge plasmas using measured and calculated ionization cross sections  

E-print Network

Turbulent transport of trace impurities impurities in the edge and scrape-off-layer of tokamak fusion plasmas is modelled by three dimensional electromagnetic gyrofluid computations including evolution of plasma profile gradients. The source function of impurity ions is dynamically computed from pre-determined measured and calculated electron impact ionization cross section data. The simulations describe the generation and further passive turbulent E-cross-B advection of the impurities by intermittent fluctuations and coherent filamentary structures (blobs) across the scrape-off-layer.

Kendl, Alexander

2014-01-01

313

Glucose transport carrier of human erythrocytes. Radiation target size measurement based on flux inactivation  

SciTech Connect

Intact human erythrocytes frozen in the presence of cryoprotective reagents and irradiated with an electron beam retained their diffusion barrier to L-glucose. The carrier-mediated flux of D-glucose, on the other hand, was inactivated as a simple exponential function of the radiation dose. Classical target size analysis of this data yielded a molecular size of 185,000 daltons for the carrier. This represents the first measurement of the functional size of a transport protein based directly on flux inactivation.

Cuppoletti, J.; Jung, C.Y.; Green, F.A.

1981-02-10

314

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

315

Measurement of Temperature, Density, and Particle Transport with Localized Dopants in Wire-Array Z Pinches  

SciTech Connect

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

Jones, B.; Deeney, C.; McKenney, J. L.; Ampleford, D. J.; Coverdale, C. A. [Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States); LePell, P. D.; Shelton, K. P. [Ktech Corp., Albuquerque, New Mexico 87123 (United States); Safronova, A. S.; Kantsyrev, V. L.; Osborne, G.; Sotnikov, V. I.; Ivanov, V. V.; Fedin, D.; Nalajala, V.; Yilmaz, F.; Shrestha, I. [University of Nevada, Reno, Nevada 89557 (United States)

2008-03-14

316

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

PubMed

The hybrid structures composed of gold nanoparticles and carbon nanotubes were prepared using porous alumina membranes as templates. Carbon nanotubes were synthesized inside the pores of these templates by the non-catalytic decomposition of acetylene. The inner cavity of the supported tubes was used as nanoreactors to grow gold particles by impregnation with a gold salt, followed by a calcination-reduction process. The samples were characterized by transmission electron microscopy and X-ray energy dispersion spectroscopy techniques. The resulting hybrid products are mainly encapsulated gold nanoparticles with different shapes and dimensions depending on the concentration of the gold precursor and the impregnation procedure. In order to understand the electronic transport mechanisms in these nanostructures, their conductance was measured as a function of temperature. The samples exhibit a 'non-metallic' temperature dependence where the dominant electron transport mechanism is 1D hopping. Depending on the impregnation procedure, the inclusion of gold nanoparticles inside the CNTs can introduce significant changes in the structure of the tubes and the mechanisms for electronic transport. The electrical resistance of these hybrid structures was monitored under different gas atmospheres at ambient pressure. Using this hybrid nanostructures, small amounts of acetylene and hydrogen were detected with an increased sensibility compared with pristine carbon nanotubes. Although the sensitivity of these hybrid nanostructures is rather low compared to alternative sensing elements, their response is remarkably fast under changing gas atmospheres. PMID:24910571

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

2014-01-01

317

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

NASA Astrophysics Data System (ADS)

The hybrid structures composed of gold nanoparticles and carbon nanotubes were prepared using porous alumina membranes as templates. Carbon nanotubes were synthesized inside the pores of these templates by the non-catalytic decomposition of acetylene. The inner cavity of the supported tubes was used as nanoreactors to grow gold particles by impregnation with a gold salt, followed by a calcination-reduction process. The samples were characterized by transmission electron microscopy and X-ray energy dispersion spectroscopy techniques. The resulting hybrid products are mainly encapsulated gold nanoparticles with different shapes and dimensions depending on the concentration of the gold precursor and the impregnation procedure. In order to understand the electronic transport mechanisms in these nanostructures, their conductance was measured as a function of temperature. The samples exhibit a `non-metallic' temperature dependence where the dominant electron transport mechanism is 1D hopping. Depending on the impregnation procedure, the inclusion of gold nanoparticles inside the CNTs can introduce significant changes in the structure of the tubes and the mechanisms for electronic transport. The electrical resistance of these hybrid structures was monitored under different gas atmospheres at ambient pressure. Using this hybrid nanostructures, small amounts of acetylene and hydrogen were detected with an increased sensibility compared with pristine carbon nanotubes. Although the sensitivity of these hybrid nanostructures is rather low compared to alternative sensing elements, their response is remarkably fast under changing gas atmospheres.

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

2014-05-01

318

Measurement of absolute CO number densities in CH3F/O2 plasmas by optical emission self-actinometry  

NASA Astrophysics Data System (ADS)

CH3F/O2 inductively coupled plasmas at 10 mTorr were investigated using optical emission spectroscopy. A ‘self-actinometry’ method was developed to measure the absolute number density of CO that formed in reactions following dissociation of CH3F and O2 in the plasma. In this method, small amounts of CO were added to the plasma, leading to small increases in the CO emission intensity. By carefully accounting for small perturbations to the plasma electron density and/or electron energy distribution, and by showing that very little of the CO added to the plasma was decomposed by electron impact or other reactions, it was possible to derive absolute number densities for the CO content of the plasma. With equal fractions (0.50) of CH3F and O2 in the feed gas, the CO mole fraction as a function of plasma power saturated at a value of 0.20-0.25. As O2 in the feed gas was varied at a constant power of 100 W, the CO mole fraction went through a maximum of about 0.25 near an O2 feed gas fraction of 0.5. The relative CO number densities determined by ‘standard’ actinometry followed the same functional dependence as the absolute mole fractions determined by self-actinometry, aided by the fact that electron temperature did not change appreciably with power or feed gas composition.

Karakas, Erdinc; Kaler, Sanbir; Lou, Qiaowei; Donnelly, Vincent M.; Economou, Demetre J.

2014-02-01

319

Surplus Bid Cell Number  

E-print Network

Surplus Bid Form Name: Cell Number: Email Address: Fax Number: Item Number: Item Description: Bid the internal section below) Phone Number: FOR DALHOUSIE INTERNAL BID USE ONLY Department: Account Number (for costs associated with transportation of items from its current location. · All sales are final

Brownstone, Rob

320

On measurements and their quality. Paper 4: verbal anchors and the number of response options in rating scales.  

PubMed

This is the last in a short series of papers on measurement theory and practice with particular relevance to intervention research in nursing, midwifery, and healthcare. Understanding how it is that people respond to the questions posed by researchers is fundamental to progress in the social and health sciences. For decades methodologists in psychology, marketing, education, and survey research have studied this issue. In this paper I review this diverse empirical literature to synthesize basic principles for creating rating scales which can reduce measurement error and increase the quality of resulting data. After introducing a theoretical framework known as the cognitive aspects of survey methods (CASM), I review the fundamentals of psychological scaling theory and discuss how it has been used to study the meanings of verbal response options and provide an illustration of how the quality of measurements may be influenced by our choice of the verbal phrases we present as response options. Next, I review the research on the optimal number of response options to use in various measurement situations and how verbal and numeric anchors can combine to influence data quality. Finally, I summarize the issues covered and present recommendations for best practice when creating and using rating scales in research. PMID:24125584

Beckstead, Jason W

2014-05-01

321

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

PubMed

Despite improved control measures, Ebola remains a serious public health risk in African regions where recurrent outbreaks have been observed since the initial epidemic in 1976. Using epidemic modeling and data from two well-documented Ebola outbreaks (Congo 1995 and Uganda 2000), we estimate the number of secondary cases generated by an index case in the absence of control interventions R0. Our estimate of R0 is 1.83 (SD 0.06) for Congo (1995) and 1.34 (SD 0.03) for Uganda (2000). We model the course of the outbreaks via an SEIR (susceptible-exposed-infectious-removed) epidemic model that includes a smooth transition in the transmission rate after control interventions are put in place. We perform an uncertainty analysis of the basic reproductive number R0 to quantify its sensitivity to other disease-related parameters. We also analyse the sensitivity of the final epidemic size to the time interventions begin and provide a distribution for the final epidemic size. The control measures implemented during these two outbreaks (including education and contact tracing followed by quarantine) reduce the final epidemic size by a factor of 2 relative the final size with a 2-week delay in their implementation. PMID:15178190

Chowell, G; Hengartner, N W; Castillo-Chavez, C; Fenimore, P W; Hyman, J M

2004-07-01

322

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...

323

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

E-print Network

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

Johnson, Jeremy A.

324

Pilot Study on Rugged Fiber Optic Brillouin Sensors for Large-Strain Measurements to Ensure the Safety of Transportation Structures.  

National Technical Information Service (NTIS)

Brillouin-scattering Optical Time Domain Reflectometry (BOTDR) is a viable technology for simultaneous, distributed strain and temperature measurements for miles-long transportation structures. It is a promising tool to ensure the smooth operation and saf...

G. Chen, H. Xiao, Y. Huang, Z. Zhou

2012-01-01

325

Transporter  

Microsoft Academic Search

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

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

326

Bedload transport formulae calibration using a single measurement: testing high and low  

NASA Astrophysics Data System (ADS)

Due to the difficulty in accurately predicting bedload transport using traditional equations, bedload samples are often collected in the field and used to calibrate predictions. However, sampling bedload is time consuming and expensive. In lieu of conducting an exhaustive sampling campaign in the field, some researchers have recommended collecting one to three low flow samples in the field. This work addresses the question of whether a single bedload measurement near bankfull is more successful at calibrating a predictive equation than a low flow measurement. The Pagosa Good/Fair, Wilcock Surface-based Two Fraction, and Barry et al. General Power Equation formulae are compared using a single calibration point at low flow and then another at bankfull discharge. The comparison is conducted using 2,500 measurements from a database of a total of 8,000 available measurements. The results show that a measurement at bankfull is a better predictor than a low flow measurement, but acceptable results at low flow are provided by the Pagosa and Barry formulae. This work also recommends that sampling methodology be a consideration for formula selection. In other words, certain formulae work better for Helley-Smith samplers while others are better suited for data collected in net or pit traps. For example, the predictive curve produced by the Pagosa and Barry formulae better fit Helley-Smith data than the Wilcock, which is recommended for data collected in net or pit traps.

Hinton, D. D.; Hotchkiss, R. H.

2012-12-01

327

Identifying fire plumes in the Arctic with tropospheric FTIR measurements and transport models  

NASA Astrophysics Data System (ADS)

We investigate Arctic tropospheric composition using ground-based Fourier Transform Infrared (FTIR) solar absorption spectra, recorded at the Polar Environment Atmospheric Research Laboratory (PEARL, Eureka, Nunavut, Canada, 80°5' N, 86°42' W) and at Thule (Greenland, 76°53' N, -68°74' W) from 2008 to 2012. The target species: carbon monoxide (CO), hydrogen cyanide (HCN), ethane (C2H6), acetylene (C2H2), formic acid (HCOOH), and formaldehyde (H2CO) are emitted by biomass burning and can be transported from mid-latitudes to the Arctic. By detecting simultaneous enhancements of three biomass burning tracers (HCN, CO, and C2H6), ten and eight fire events are identified at Eureka and Thule, respectively, within the five-year FTIR timeseries. Analyses of Hybrid Single Particle Lagrangian Integrated Trajectory Model (HYSPLIT) back-trajectories coupled with Moderate Resolution Imaging Spectroradiometer (MODIS) fire hot spot data, Stochastic Time-Inverted Lagrangian Transport model (STILT) footprints, and Ozone Monitoring Instrument (OMI) UV aerosol index maps are used to attribute burning source regions and travel time durations of the plumes. By taking into account the effect of aging of the smoke plumes, measured FTIR enhancement ratios were corrected to obtain emission ratios and equivalent emission factors. The means of emission factors for extratropical forest estimated with the two FTIR datasets are 0.39 ± 0.15 g kg-1 for HCN, 1.23 ± 0.49 g kg-1 for C2H6, 0.34 ± 0.16 g kg-1 for C2H2, 2.13 ± 0.92 g kg-1 for HCOOH, and 3.14 ± 1.28 g kg-1 for CH3OH. To improve our knowledge concerning the dynamical and chemical processes associated with Arctic pollution from fires, the two sets of FTIR measurements were compared to the Model for Ozone and Related chemical Tracers, version 4 (MOZART-4). Seasonal cycles and day-to-day variabilities were compared to assess the ability of the model to reproduce emissions from fires and their transport. Good agreement in winter confirms that transport is well implemented in the model. For C2H6, however, the lower wintertime concentration estimated by the model as compared to the FTIR observations highlight an underestimation of its emission. Results show that modelled and measured total columns are correlated (linear correlation coefficient r > 0.6 for all gases except for H2CO at Eureka and HCOOH at Thule), but suggest a~general underestimation of the concentrations in the model for all seven tropospheric species in the high Arctic.

Viatte, C.; Strong, K.; Hannigan, J.; Nussbaumer, E.; Emmons, L.; Conway, S.; Paton-Walsh, C.; Hartley, J.; Benmergui, J.; Lin, J.

2014-10-01

328

Epithelial barrier and ion transport in coeliac sprue: electrical measurements on intestinal aspiration biopsy specimens.  

PubMed Central

Epithelial barrier function and ion transport was studied in coeliac sprue using a miniaturised Ussing device for measurements on diagnostic aspiration biopsy specimens from the jejunum of untreated or gluten free nourished sprue patients, or from healthy controls. Pure epithelial resistance (Re) indicating epithelial barrier function was determined by transmural alternating current impedance analysis. It was reduced by 56% in acute sprue mean (SEM) (9 (1) omega.cm2) compared with controls (20(2) omega.cm2). In gluten free nourished sprue patients Re was only partly recovered (15 (1) omega.cm2). Subepithelial resistance (Rsub) was also changed from 28 (1) omega.cm2- in control to 17 (1) omega.cm2 in acute sprue because of the change in mucosal architecture, but was unchanged in gluten free nourished sprue patients (29 (4) omega.cm2). In acute sprue, unidirectional Na+ and Cl- fluxes were increased in both directions as a consequence of the decreased resistance. However, short circuit current (ISC) as well as Na+ and Cl- net fluxes were not significantly different from control. Subsequently, the electrogenic Cl- secretory system was investigated. After maximal stimulation with theophylline and prostaglandin E1, a Cl(-)-dependent increase in ISC was obtained in the sprue mucosa and control jejunum. It showed saturation characteristics and was blockable by serosal bumetanide. When compared with control, neither Km nor Vmax of this electrogenic Cl- secretion was significantly changed in coeliac sprue. In conclusion, a miniaturised Ussing device was used for transport measurements on intestinal biopsy specimens. In acute coeliac disease, the epithelial barrier of the jejunum was seriously disturbed. The active electrogenic Cl- secretory transport system was present in the sprue mucosa, but was not activated in the Ussing chamber in vitro when compared with control jejunum. PMID:8537047

Schulzke, J D; Schulzke, I; Fromm, M; Riecken, E O

1995-01-01

329

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

2011-01-01

330

Monitoring of magnetization processes in GaMnAs ferromagnetic film by electrical transport measurement  

NASA Astrophysics Data System (ADS)

The transport measurement technique has been adapted to investigate the magnetization processes of GaMnAs ferromagnetic semiconductor film. While the planar Hall resistance (PHR) reached different values at 3 K in each attempt for zero field cooling (ZFC) process, it always ended the same value in the field cooling (FC) process. This indicates that the GaMnAs film in the absence of magnetic field magnetized randomly among four magnetic easy axes along <1 0 0> directions without preference of specific direction, while the presence of the magnetic field provides preference of the magnetization to specific direction. The PHR measured with and without external magnetic field in the heating process also showed significantly different behavior, which originate from the temperature dependence of magnetic anisotropy in the GaMnAs film.

Shin, D. Y.; Lee, Sanghoon; Liu, X.; Furdyna, J. K.

2009-01-01

331

Rapid Measurement of Molecular Transport and Interaction inside Living Cells Using Single Plane Illumination  

PubMed Central

The ability to measure biomolecular dynamics within cells and tissues is very important to understand fundamental physiological processes including cell adhesion, signalling, movement, division or metabolism. Usually, such information is obtained using particle tracking methods or single point fluctuation spectroscopy. We show that image mean square displacement analysis, applied to single plane illumination microscopy data, is a faster and more efficient way of unravelling rapid, three-dimensional molecular transport and interaction within living cells. From a stack of camera images recorded in seconds, the type of dynamics such as free diffusion, flow or binding can be identified and quantified without being limited by current camera frame rates. Also, light exposure levels are very low and the image mean square displacement method does not require calibration of the microscope point spread function. To demonstrate the advantages of our approach, we quantified the dynamics of several different proteins in the cyto- and nucleoplasm of living cells. For example, from a single measurement, we were able to determine the diffusion coefficient of free clathrin molecules as well as the transport velocity of clathrin-coated vesicles involved in endocytosis. Used in conjunction with dual view detection, we further show how protein-protein interactions can be quantified. PMID:25394360

Hedde, Per Niklas; Stakic, Milka; Gratton, Enrico

2014-01-01

332

SO2 measurements at a high altitude site in the central Himalayas: Role of regional transport  

NASA Astrophysics Data System (ADS)

Continuous measurements of a climatically important acidic gas, SO2, were made over Nainital (29.37°N, 79.45°E; 1958 m amsl), a regionally representative site in the central Himalayas, for the first time during 2009-2011. Unlike many other sites, the SO2 levels over Nainital are higher during pre-monsoon (345 pptv) compared to winter (71 pptv). High values during pre-monsoon are attributed to the transport of air masses from regions viz. Indo-Gangetic Plain (IGP), northern India and north-East Pakistan, which are dotted with numerous industries and power plants, where coal burning occurs. Transport from the polluted regions is evinced from good correlations of SO2 with wind speed, NOy and UV aerosol index during these periods. Daytime elevations in SO2 levels, influenced by 'valley winds' and boundary layer evolution, is a persistent feature at Nainital. SO2 levels are very much lower during monsoon compared to pre-monsoon, due to oxidation losses and wet scavenging. Despite this, SO2/NOy slopes are high (>0.4) both during pre-monsoon and monsoon, indicating impacts of point sources. The SO2 levels during winter are lower as the measurement site is cut off from the plains due to boundary layer dynamics. Further, the SO2 levels during winter nights are the lowest (lesser than 50 pptv) and resemble free tropospheric conditions.

Naja, Manish; Mallik, Chinmay; Sarangi, Tapaswini; Sheel, Varun; Lal, Shyam

2014-12-01

333

X-ray and neutron reflectivity measurements of moisture transport through model multilayered barrier films for flexible displays  

NASA Astrophysics Data System (ADS)

One encapsulation approach to extend the lifetime of flexible organic light-emitting diode (OLED) devices uses inorganic Al2O3-polymer multilayer barrier films. However, a recent theoretical examination of multilayer barriers indicated that the barriers should not be effective for OLED applications, despite empirical evidence of success. It was suggested that a long-lived transient process in the transport of water molecules through multilayer films is responsible for its practical success, but has not been directly observed experimentally. X-ray reflectivity (XR) and neutron reflectivity measurements are used to measure permeation rates and structural changes in model barrier films upon exposure to water vapor. A film consisting of a stack of an undercured organic and the typical inorganic phases was found to barely swell [(7±5)Å] after an 11-d exposure to moisture [60 °C, 100% relative humidity (RH)]. Current measurements of ultralow moisture permeation assume that 10 d is sufficient for the equilibrium measurement, but XR data show that a stack of three dyad layers may require as many as 500 d (>12000h) to reach equilibrium. Barriers with a high number of defects in the inorganic phase reached equilibrium after 6 d of exposure to moisture (60 °C, 100% RH). Over this time scale, water breakthrough at each layer can be observed from XR. Neutron reflectivity measurements with deuterated water show an accumulation of water near the aluminum oxide/polymer interface. This interface behaves similar to a desiccant, where the permeation of water through the barrier is retarded by the strong adsorption of water to aluminum oxide. This internal desiccant effect of the multilayered structure is clearly delineated and appears to be responsible for the long-term transient behavior of these barrier materials.

Vogt, Bryan D.; Lee, Hae-Jeong; Prabhu, Vivek M.; DeLongchamp, Dean M.; Lin, Eric K.; Wu, Wen-li; Satija, Sushil K.

2005-06-01

334

ICET - International Collaboration on Experiments in Turbulence: Coordinated Measurements in High Reynolds Number Turbulent Boundary Layers from Three Wind Tunnels  

NASA Astrophysics Data System (ADS)

Zero pressure gradient (ZPG) boundary layers are one of the canonical, wall-bounded, turbulent flows that have been the focus of experimental and analytical investigations for several decades. Over the past few years, four groups have focused on systematic comparison between several measurement techniques and three facilities. Two closed return wind tunnels with ZPG boundary layers developed on a plate suspended near the mid-height of the test section (at KTH and IIT), and an open return facility with a large and long test section and a boundary layer developing along its floor (at the University of Melbourne), are used for these coordinated efforts. The development length of the boundary layers and the free-stream velocity in the three facilities range from 5.5 to 22 m, and from 10 to 60 m/s, respectively. Various arrangements for adjustable test section ceilings are employed to generate ZPG boundary layers over the range of momentum thickness Reynolds numbers from 11,000 to 70,000. Oil film interferometry (OFI) is employed to directly measure the wall shear stress, and various sizes of Pitot probes and types of hot-wire sensors are used to measure wall-normal velocity profiles at different locations and free-stream velocities. Mean velocity, turbulence statistics and integral parameters are examined.

Nagib, H.; Smits, A.; Marusic, I.; Alfredsson, P. H.

2009-11-01

335

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

NASA Astrophysics Data System (ADS)

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

Manga, Michael; Patel, Ameeta; Dufek, Josef

2010-05-01

336

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

PubMed

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

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

2012-10-01

337

Confined Nonthermal Alpha Distribution and Transport Measurements in D-T Plasmas on Tftr  

NASA Astrophysics Data System (ADS)

A high sensitivity diagnostic system has been developed to provide the first observation of confined nonthermal alpha particles produced in a reactor-grade deuterium-tritium (D-T) fusion plasma. These absolutely calibrated measurements of the energy distribution and spatial profiles have allowed testing of fast alpha slowing -down models and determination of fast alpha cross-field transport. The new alpha-CHERS diagnostic is a charge exchange recombination spectroscopy (CHERS) system specifically designed to observe the Doppler-shifted n = 4-3 transition of He^{+1} near lambda_{o } = 468.6 nm. The intensity of the fast alpha spectral feature is less than 1% of the bremsstrahlung continuum background, and its measurement requires greater than 100 times more light throughput than previous CHERS diagnostics. The required sensitivity is achieved with high throughput optics and high-quantum-efficiency, high -dynamic-range low-noise detectors. Analysis techniques are developed to allow extraction of the photon-noise-limited alpha signal from the continuum background and impurity emissions. These results demonstrate the small signal extraction methods required for active beam spectroscopy measurements of ion temperature, impurity density, plasma rotation, and current density in large, high-density plasmas in future reactors such as ITER. Spatial, temporal and energy-resolved measurements of the alpha distribution for E_{alpha }<=q 0.7 MeV have been obtained in D -T plasmas on the Tokamak Fusion Test Reactor (TFTR). During a sawtooth-free discharge, the measured alpha energy spectrum is in good agreement with that predicted on the basis of neoclassical transport. Time-resolved measurements during the alpha thermalization period after alpha source turn -off show decay of the distribution function to lower energies consistent with the classical slowing-down time of about 0.5 sec. Radial profiles are best characterized by a slowing -down alpha distribution subject to neoclassical plus a small anomalous cross-field diffusion with an effective anomalous diffusion coefficient in the range D _{alpha,a} = 0.00 -0.03 m^2/s, well below the previous upper limit of 0.1 m^2/s determined from fast ion measurements. In addition, sawtooth redistribution of core alphas is observed.

McKee, George Raymond, Jr.

338

The Degree of Segmental Aneuploidy Measured by Total Copy Number Abnormalities Predicts Survival and Recurrence in Superficial Gastroesophageal Adenocarcinoma  

PubMed Central

Background Prognostic biomarkers are needed for superficial gastroesophageal adenocarcinoma (EAC) to predict clinical outcomes and select therapy. Although recurrent mutations have been characterized in EAC, little is known about their clinical and prognostic significance. Aneuploidy is predictive of clinical outcome in many malignancies but has not been evaluated in superficial EAC. Methods We quantified copy number changes in 41 superficial EAC using Affymetrix SNP 6.0 arrays. We identified recurrent chromosomal gains and losses and calculated the total copy number abnormality (CNA) count for each tumor as a measure of aneuploidy. We correlated CNA count with overall survival and time to first recurrence in univariate and multivariate analyses. Results Recurrent segmental gains and losses involved multiple genes, including: HER2, EGFR, MET, CDK6, KRAS (recurrent gains); and FHIT, WWOX, CDKN2A/B, SMAD4, RUNX1 (recurrent losses). There was a 40-fold variation in CNA count across all cases. Tumors with the lowest and highest quartile CNA count had significantly better overall survival (p?=?0.032) and time to first recurrence (p?=?0.010) compared to those with intermediate CNA counts. These associations persisted when controlling for other prognostic variables. Significance SNP arrays facilitate the assessment of recurrent chromosomal gain and loss and allow high resolution, quantitative assessment of segmental aneuploidy (total CNA count). The non-monotonic association of segmental aneuploidy with survival has been described in other tumors. The degree of aneuploidy is a promising prognostic biomarker in a potentially curable form of EAC. PMID:24454681

Davison, Jon M.; Yee, Melissa; Krill-Burger, J. Michael; Lyons-Weiler, Maureen A.; Kelly, Lori A.; Sciulli, Christin M.; Nason, Katie S.; Luketich, James D.; Michalopoulos, George K.; LaFramboise, William A.

2014-01-01

339

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. PMID:23383111

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

2013-01-01

340

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. PMID:24002085

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

2013-01-01

341

Automated pressure probe for measurement of water transport properties of higher plant cells  

NASA Astrophysics Data System (ADS)

A computer-assisted instrument was constructed to measure the fundamental physical properties that regulate water transport at the cell level in plants. With this automated pressure probe, we measure a cell's hydrostatic pressure by inserting an oil-filled glass capillary into the cell. The capillary is connected to a pressure sensor and to a plunger controlled by a stepper motor. At the capillary tip an interface forms between the cell sap and oil. The image of this interface is directed through a microscope to a video camera. The interface position is detected by a video processor sampling at 60 Hz and is regulated by a microcomputer which advances or retracts the plunger at rates up to 280 steps per second. To determine the hydraulic conductance of cell membranes, the computer carries out pressure-relaxation and pressure-clamp experiments. Pressure is recorded with a resolution of 0.02 bar and is regulated in pressure-clamp experiments at ±0.02 bar. The instrument measures the cell volumetric elastic modulus by injecting or removing small volumes from the cell while simultaneously measuring cell turgor pressure. This system was tested on the cells of pea seedlings and proved superior to the previous techniques, especially for pressure-clamp experiments and volumetric elastic modulus determinations.

Cosgrove, Daniel J.; Durachko, Daniel M.

1986-10-01

342

Rotating Disk Electrode Voltammetric Measurements of Serotonin Transporter Kinetics in Synaptosomes  

PubMed Central

Altered serotonin (5-HT) signaling is implicated in several neuropsychiatric disorders, including depression, anxiety, obsessive-compulsive disorder, and autism. The 5-HT transporter (SERT) modulates 5-HT neurotransmission strength and duration. This is the first study using rotating disk electrode voltammetry (RDEV) to measure 5-HT clearance. SERT kinetics were measured in whole brain synaptosomes. Uptake kinetics of exogenous 5-HT were measured using glassy carbon electrodes rotated in 500 uL glass chambers containing synaptosomes from SERT-knockout (?/?), heterozygous (+/?), or wild-type (+/+) mice. RDEV detected 5-HT concentrations of 5 nM and higher. Initial velocities were kinetically resolved with Km and Vmax values of 99 ± 35 standard error of regression (SER) nM and 181 ± 11 SER fmol / (s x mg protein), respectively in wild-type synaptosomes. The method enables control over drug and chemical concentrations, facilitating interpretation of results. Results are compared in detail to other techniques used to measure SERT kinetics, including tritium labeled assays, chronoamperometry, and fast scan cyclic voltammetry. RDEV exhibits decreased 5-HT detection limits, decreased vulnerability to 5-HT oxidation products that reduce electrode sensitivity, and also overcomes diffusion limitations via forced convection by providing a continuous, kinetically resolved signal. Finally, RDEV distinguishes functional differences between genotypes, notably, between wild-type and heterozygous mice, an experimental problem with other experimental approaches. PMID:20713085

Hagan, Catherine E.; Neumaier, John F.; Schenk, James O.

2010-01-01

343

Surface transport in the Northeastern Adriatic Sea from FSLE analysis of HF radar measurements  

NASA Astrophysics Data System (ADS)

This study focuses on the surface transport in the Northeastern Adriatic Sea and the related hydrodynamic connectivity with the Gulf of Trieste (GoT) under calm or typical wind conditions: Bora (from the NE) and Sirocco (from the SE). The surface transport in the area has been investigated by evaluating the Finite-Size Lyapunov Exponents (FSLE) on the current field measured by the High Frequency (HF) coastal radar network. FSLE allow us to estimate Lagrangian Coherent Structures (LCSs), which provide information on the transport patterns associated with the flow and identify regions characterized by different dynamics. This work includes the development and set-up of the FSLE algorithm applied for the first time to the specific Adriatic area considered. The FSLE analysis during calm wind reveals an attractive LCS crossing the GoT entrance, marking the convergence between the Northern Adriatic and the outflowing gulf waters. During Bora episodes this attractive LCS is displaced westward with respect to the calm wind case, indicating that Bora drives an extended coherent outflow from the GoT. On the other hand, Sirocco wind piles up the water along the northern end of the basin. In this area an attractive LCS is found, extending mainly in the SW-NE direction. The sirocco-induced inflow of Adriatic waters in the GoT is mainly driven along its northern (Italian) side, as evidenced by the orientation of the LCS. Under Sirocco condition, as in the Bora case, there is no barrier in front of the gulf. No relevant LCSs are observed in the southern radar coverage area except for Bora cases, when a repulsive LCS develops in front of the Istrian coast separating water masses to the North and the South of it.

Berta, Maristella; Ursella, Laura; Nencioli, Francesco; Doglioli, Andrea M.; Petrenko, Anne A.; Cosoli, Simone

2014-04-01

344

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

NASA Technical Reports Server (NTRS)

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

Zapata, Edgar; McCleskey, Carey

2014-01-01

345

Transport Measurements on NEODYMIUM(1.85) CERIUM(.15) Copper OXYGEN(4-DELTA) Thin Films  

NASA Astrophysics Data System (ADS)

This work describes the synthesis and the study of the transport properties of thin films of Nd _{1.85}Ce_{.15 }CuO_{4-delta} carried out respectively at the IBM T. J. Watson Research Center in collaboration with Dr. A. Gupta, and at the Francis Bitter National Magnet Laboratory under the direction of Dr. P. M. Tedrow. The thin films were prepared by laser ablation of a stoichiometric target on heated substrates in a reactive ambient. The influence of the deposition parameters was studied, and the use of a nitreous oxide ambient was found to yield a clear improvement of the sample quality. The transport properties of the films were measured at low temperatures and in high magnetic fields. Non superconducting samples showed a strong, highly anisotropic, negative magnetoresistance that is consistent with two dimensional weak-localization. Superconducting samples show two dimensional fluctuation effects above T_{c}. The theory of fluctuations in a magnetic field was used to extract the position of H_{c2} (in the perpendicular direction) in the broad and almost featureless resistive transition, and the extracted values were fit to the theory of dirty superconductors. The angular dependence of the resistive transition was studied close to T _{c} and found to be somewhat better described by a two-dimensional model. (Copies available exclusively from MIT Libraries, Rm. 14-0551, Cambridge, MA 02139-4307. Ph. 617-253-5668; Fax 617-253-1690.).

Kussmaul, Andreas

1992-01-01

346

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] [Johns Hopkins Univ., Baltimore, MD (United States). Dept. of Biology

1998-12-01

347

Transport critical current measurements on a Cu-substituted BaFe2As2 superconductor  

NASA Astrophysics Data System (ADS)

The critical current density Jc is a crucial parameter to establish the actual technological potential of a superconducting (SC) material. Furthermore, being proportional to the SC gap parameter, it can reveal important information about the microscopic nature of the SC state in a given material. The FeAs-based class of SC materials has been a focus of intense scientific investigation lately, but direct investigation of Jc by transport measurements is rather scarce in literature. For these materials, it is very interesting to map Jc as a function of their distinct SC tuning parameters such as applied pressure and chemical substitution. In this work, detailed investigation of the field, temperature, and pressure dependences of transport critical current density Jc for Cu-substituted BaFe2As2 single crystals is reported. In this particular material, Cu-substitution has a strong magnetic pair breaking effect. However, with increasing pressure, this sample shows an almost twofold increase of Tc, from 3.2 K to 6.9 K, which is followed by an increase in Jc. These observations are discussed considering the presence of magnetic pinning centers in the Fe-As plane, which, in principle, could suggest effective routes to increase Jc in the this class of materials.

Garitezi, T. M.; Rosa, P. F. S.; Adriano, C.; Pagliuso, P. G.

2014-05-01

348

Advanced Transport Delay Compensation Algorithms: Results of Delay Measurement and Piloted Performance Tests  

NASA Technical Reports Server (NTRS)

This report summarizes the results of delay measurement and piloted performance tests that were conducted to assess the effectiveness of the adaptive compensator and the state space compensator for alleviating the phase distortion of transport delay in the visual system in the VMS at the NASA Langley Research Center. Piloted simulation tests were conducted to assess the effectiveness of two novel compensators in comparison to the McFarland predictor and the baseline system with no compensation. Thirteen pilots with heterogeneous flight experience executed straight-in and offset approaches, at various delay configurations, on a flight simulator where different predictors were applied to compensate for transport delay. The glideslope and touchdown errors, power spectral density of the pilot control inputs, NASA Task Load Index, and Cooper-Harper rating of the handling qualities were employed for the analyses. The overall analyses show that the adaptive predictor results in slightly poorer compensation for short added delay (up to 48 ms) and better compensation for long added delay (up to 192 ms) than the McFarland compensator. The analyses also show that the state space predictor is fairly superior for short delay and significantly superior for long delay than the McFarland compensator.

Guo, Liwen; Cardullo, Frank M.; Kelly, Lon C.

2007-01-01

349

GIS measured environmental correlates of active school transport: A systematic review of 14 studies  

PubMed Central

Background Emerging frameworks to examine active school transportation (AST) commonly emphasize the built environment (BE) as having an influence on travel mode decisions. Objective measures of BE attributes have been recommended for advancing knowledge about the influence of the BE on school travel mode choice. An updated systematic review on the relationships between GIS-measured BE attributes and AST is required to inform future research in this area. The objectives of this review are: i) to examine and summarize the relationships between objectively measured BE features and AST in children and adolescents and ii) to critically discuss GIS methodologies used in this context. Methods Six electronic databases, and websites were systematically searched, and reference lists were searched and screened to identify studies examining AST in students aged five to 18 and reporting GIS as an environmental measurement tool. Fourteen cross-sectional studies were identified. The analyses were classified in terms of density, diversity, and design and further differentiated by the measures used or environmental condition examined. Results Only distance was consistently found to be negatively associated with AST. Consistent findings of positive or negative associations were not found for land use mix, residential density, and intersection density. Potential modifiers of any relationship between these attributes and AST included age, school travel mode, route direction (e.g., to/from school), and trip-end (home or school). Methodological limitations included inconsistencies in geocoding, selection of study sites, buffer methods and the shape of zones (Modifiable Areal Unit Problem [MAUP]), the quality of road and pedestrian infrastructure data, and school route estimation. Conclusions The inconsistent use of spatial concepts limits the ability to draw conclusions about the relationship between objectively measured environmental attributes and AST. Future research should explore standardizing buffer size, assess the quality of street network datasets and, if necessary, customize existing datasets, and explore further attributes linked to safety. PMID:21545750

2011-01-01

350

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

PubMed Central

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

2004-01-01

351

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

2004-09-01

352

Opacity and transport measurements reveal that dilute plasma models of sonoluminescence are not valid.  

PubMed

A strong interaction between a nanosecond laser and a 70 ?m radius sonoluminescing plasma is achieved. The overall response of the system results in a factor of 2 increase in temperature as determined by its spectrum. Images of the interaction reveal that light energy is absorbed and trapped in a region smaller than the sonoluminescence emitting region of the bubble for over 100 ns. We interpret this opacity and transport measurement as demonstrating that sonoluminescencing bubbles can be 1000 times more opaque than what follows from the Saha equation of statistical mechanics in the ideal plasma limit. To address this discrepancy, we suggest that the effects of strong Coulomb interactions are an essential component of a first principles theory of sonoluminescence. PMID:22463411

Khalid, Shahzad; Kappus, Brian; Weninger, Keith; Putterman, Seth

2012-03-01

353

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)] [CRISMAT ISMRA Centre National de la Recherche Scientifique, 6 Bd Mal Juin, 14050 Caen (France)

1996-12-01

354

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

355

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 YBa2Cu3O(7-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

356

Spectroscopic density and temperature measurements and modelling of a discharge plasma for neutralized ion-beam transport  

Microsoft Academic Search

High-current discharge channels are ideally suited for the focusing and transport of intense charged particle beams. The azimuthal magnetic field provides a strong focusing force, which acts symmetrically towards the discharge axis. A sufficiently dense and hot plasma can also neutralize the beam current and space charge of very intense ion beams, relevant to a number of future applications. In

C. Niemann; F. B. Rosmej; A. Tauschwitz; S. Neff; D. Penache; R. Birkner; C. Constantin; R. Knobloch; R. Presura; D. H. H. Hoffmann; S. S. Yu; R. W. Lee

2003-01-01

357

Transport into retina measured by short vascular perfusion in the rat.  

PubMed Central

1. The short duration cerebrovascular perfusion method for measuring permeability of the blood-brain barrier has been adapted to measuring transport into the retina. 2. The method has been characterized on the one hand by comparing uptakes of radiotracers during HCO3(-)-buffered saline perfusion with those occurring after intravenous bolus injection of radioisotopes, and on the other by comparing uptake into retina with the uptake into frontal cerebral cortex. The mean permeability-surface area (PS) products (ml s-1 g-1) for [14C]urea and [14C]thiourea in the perfused retina were 1.2 +/- 0.26 x 10(-3) and 2.1 +/- 0.01 x 10(-3) respectively. The intravenous injection method gave comparable values for [14C]urea and [14C]thiourea of 1.6 +/- 0.28 x 10(-3) and 3.24 +/- 0.55 x 10(-3). The rates of uptake of the hydrophilic solutes were 2- to 7-fold greater than in brain. 3. Retinal and choroidal capillary perfusion fluid flow rates were measured using a diffusible flow marker ([14C]diazepam) and a particulate indicator (15 microns cerium141-labelled microspheres). Results using both flow markers confirmed that both capillary networks supplying the retina were being adequately perfused. PMID:8308748

Gratton, J A; Lightman, S L; Bradbury, M W

1993-01-01

358

Effect of sampling time on measured gravel bed load transport rates in a coarse-bedded stream  

NASA Astrophysics Data System (ADS)

This study empirically quantified the effect of sampling time on measured transport rates and fitted rating curves based on results obtained from bed load traps deployed for 2, 10, and 60 min in a coarse-bedded stream. As expected for a skewed distribution of transport rates, 2 min deployment underpredicted transport rates obtained from 10 and 60 min deployment by factors of 2 and 3 at moderate flows (50-70% Qbkf). At near-bank-full flow the underprediction by 2 min versus 10 min sampling increased to a factor of 5, while transport rates collected during 60 min deployments were reduced because of overfilled bags. At flows near incipient gravel motion, 2 min sampling overpredicted transport rates obtained by 10 and 60 min deployment by factors of 2.7 and 3.4. The overprediction is attributed to computational effects arising mainly from the lowest measurable transport rate for each sampling time. Rating curves fitted to transport rates from 2 min sampling were significantly less steep than those for longer deployment times. However, sampling time explains only a small degree of the large difference between rating curves from bed load traps and a Helley-Smith sampler (2 min sampling).

Bunte, Kristin; Abt, Steven R.

2005-11-01

359

The importance of transport model uncertainties for the estimation of CO2 sources and sinks using satellite measurements  

Microsoft Academic Search

This study presents a synthetic model intercomparison to investigate the importance of transport model errors for estimating the sources and sinks of CO2 using satellite measurements. The experiments were designed for testing the potential performance of the proposed CO2 lidar A-SCOPE, but also apply to other space borne missions that monitor total column CO2. The participating transport models IFS, LMDZ,

S. Houweling; I. Aben; F.-M. Breon; F. Chevallier; N. M. Deutscher; R. Engelen; C. Gerbig; D. W. T. Griffith; K. Hungershoefer; R. Macatangay; J. Marshall; J. Notholt; W. Peters; S. Serrar

2010-01-01

360

Transport and seismoelectric properties of porous permeable rock : numerical modeling and laboratory measurements  

E-print Network

The objective of this thesis is to better understand the transport and seismoelectric (SE) properties of porous permeable rock. Accurate information of rock transport properties, together with pore geometry, can aid us to ...

Zhan, Xin, Ph. D. Massachusetts Institute of Technology

2010-01-01

361

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

PubMed

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

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

2014-11-26

362

Measurements of mesophyll conductance, photosynthetic electron transport and alternative electron sinks of field grown wheat leaves  

Microsoft Academic Search

Photosynthetic electron transport drives the carbon reduction cycle, the carbon oxidation cycle, and any alternative electron sinks such as nitrogen reduction. A chlorophyll fluorescence— based method allows estimation of the total electron transport rate while a gas-exchange-based method can provide estimates of the electron transport needed for the carbon reduction cycle and, if the CO2 partial pressure inside the chloroplast

Francesco L oreto l; Giorgio Di Marco; Domenico Tricoli; Thomas D. Sharkey

1994-01-01

363

Ocean Waves Measurement and Analysis, Fifth International Symposium WAVES 2005, 3rd-7th, July, 2005. Madrid, Spain Paper number: 197  

E-print Network

Ocean Waves Measurement and Analysis, Fifth International Symposium WAVES 2005, 3rd-7th, July, 2005. Madrid, Spain Paper number: 197 #12;Ocean Waves Measurement and Analysis, Fifth International Symposium WAVES 2005, 3rd-7th, July, 2005. Madrid, Spain #12;Ocean Waves Measurement and Analysis, Fifth

Grilli, Stéphan T.

364

Measurements of Free-Space Oscillating Pressures Near Propellers at Flight Mach Numbers to 0.72  

NASA Technical Reports Server (NTRS)

In the course of a short flight program initiated to check the theory of Garrick and Watkins (NACA rep. 1198), a series of measurements at three stations were made of the oscillating pressures near a tapered-blade plan-form propeller and rectangular-blade plan form propeller at flight Mach numbers up to 0.72. In contradiction to the results for the propeller studied in NACA rep. 1198, the oscillating pressures in the plane ahead of the propeller were found to be higher than those immediately behind the propeller. Factors such as variation in torque and thrust distribution, since the blades of the present investigation were operating above their design forward speed, may account for this contradiction. The effect of blade plan form shows that a tapered-blade plan-form propeller will produce lower sound-pressure levels than a rectangular-blade plan-form propeller for the low blade-passage harmonics (the frequencies where structural considerations are important) and produce higher sound-pressure levels for the higher blade-passage harmonics (frequencies where passenger comfort is important).

Kurbjun, Max C; Vogeley, Arthur W

1958-01-01

365

Integration of field measurements and reactive transport modelling to evaluate contaminant transport at a sulfide mine tailings impoundment.  

PubMed

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. PMID:16844261

Brookfield, A E; Blowes, D W; Mayer, K U

2006-11-20

366

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

367

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

NASA Technical Reports Server (NTRS)

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

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

1959-01-01

368

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

PubMed

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

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

2008-02-01

369

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

370

Kelvin probe microscopy and electronic transport measurements in reduced graphene oxide chemical sensors  

NASA Astrophysics Data System (ADS)

Reduced graphene oxide (RGO) is an electronically hybrid material that displays remarkable chemical sensing properties. Here, we present a quantitative analysis of the chemical gating effects in RGO-based chemical sensors. The gas sensing devices are patterned in a field-effect transistor geometry, by dielectrophoretic assembly of RGO platelets between gold electrodes deposited on SiO2/Si substrates. We show that these sensors display highly selective and reversible responses to the measured analytes, as well as fast response and recovery times (tens of seconds). We use combined electronic transport/Kelvin probe microscopy measurements to quantify the amount of charge transferred to RGO due to chemical doping when the device is exposed to electron-acceptor (acetone) and electron-donor (ammonia) analytes. We demonstrate that this method allows us to obtain high-resolution maps of the surface potential and local charge distribution both before and after chemical doping, to identify local gate-susceptible areas on the RGO surface, and to directly extract the contact resistance between the RGO and the metallic electrodes. The method presented is general, suggesting that these results have important implications for building graphene and other nanomaterial-based chemical sensors.

Kehayias, Christopher E.; MacNaughton, Samuel; Sonkusale, Sameer; Staii, Cristian

2013-06-01

371

Kelvin probe microscopy and electronic transport measurements in reduced graphene oxide chemical sensors.  

PubMed

Reduced graphene oxide (RGO) is an electronically hybrid material that displays remarkable chemical sensing properties. Here, we present a quantitative analysis of the chemical gating effects in RGO-based chemical sensors. The gas sensing devices are patterned in a field-effect transistor geometry, by dielectrophoretic assembly of RGO platelets between gold electrodes deposited on SiO2/Si substrates. We show that these sensors display highly selective and reversible responses to the measured analytes, as well as fast response and recovery times (tens of seconds). We use combined electronic transport/Kelvin probe microscopy measurements to quantify the amount of charge transferred to RGO due to chemical doping when the device is exposed to electron-acceptor (acetone) and electron-donor (ammonia) analytes. We demonstrate that this method allows us to obtain high-resolution maps of the surface potential and local charge distribution both before and after chemical doping, to identify local gate-susceptible areas on the RGO surface, and to directly extract the contact resistance between the RGO and the metallic electrodes. The method presented is general, suggesting that these results have important implications for building graphene and other nanomaterial-based chemical sensors. PMID:23703020

Kehayias, Christopher E; MacNaughton, Samuel; Sonkusale, Sameer; Staii, Cristian

2013-06-21

372

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

373

Low velocity boron micro-pellet injector for edge and core impurity transport measurements  

SciTech Connect

A simple low velocity boron micro-pellet injector has been under development for Current Drive Experiment Upgrade (CDX-U) spherical torus edge and core impurity transport measurements, and wall conditioning. The injector consists of 16 barrels on a rotatable turret. Each barrel can be loaded with boron powder particles of diameters ranging from 1 to 40 {mu}m diameter in amounts ranging from less than 0.25 mg to more than 2 mg. A selected barrel is manually rotated into firing position using a vacuum precision rotary/linear motion feedthrough. A piezoelectric valve gas feed system triggered by CDX-U discharge timing is used to control H{sub 2} or D{sub 2} propellant gas at a cylinder pressure of 5.8{times}10{sup {minus}3thinsp} Pa (40 psi) or less. The injector barrel-to-CDX-U plasma edge distance is 0.47 m. Initial low mass injections of neutral boron beams were performed into CDX-U plasmas at a velocity of 23 m/s. Measurements were obtained with a filtered gated charge coupled device TV camera, bolometry, visible spectroscopy, and ultrasoft x-ray diagnostics. This work is in support of the present CDX-U research program and possible applications on National Spherical Torus Experiment. {copyright} {ital 1999 American Institute of Physics.}

Kugel, H.W.; Gorman, J.; Kaita, R.; Munsat, T. [Princeton Plasma Physics Laboratory, Princeton University, Princeton, New Jersey 08543 (United States)] [Princeton Plasma Physics Laboratory, Princeton University, Princeton, New Jersey 08543 (United States); Stutman, D. [Department of Physics and Astronomy, Johns Hopkins University, Baltimore, Maryland 21218 (United States)] [Department of Physics and Astronomy, Johns Hopkins University, Baltimore, Maryland 21218 (United States)

1999-01-01

374

Application of acoustic doppler current profilers for measuring three-dimensional flow fields and as a surrogate measurement of bedload transport  

USGS Publications Warehouse

Acoustic Doppler current profilers (ADCPs) have been in use in the riverine environment for nearly 20 years. Their application primarily has been focused on the measurement of streamflow discharge. ADCPs emit high-frequency sound pulses and receive reflected sound echoes from sediment particles in the water column. The Doppler shift between transmitted and return signals is resolved into a velocity component that is measured in three dimensions by simultaneously transmitting four independent acoustical pulses. To measure the absolute velocity magnitude and direction in the water column, the velocity magnitude and direction of the instrument must also be computed. Typically this is accomplished by ensonifying the streambed with an acoustical pulse that also provides a depth measurement for each of the four acoustic beams. Sediment transport on or near the streambed will bias these measurements and requires external positioning such as a differentially corrected Global Positioning Systems (GPS). Although the influence of hydraulic structures such as spur dikes and bridge piers is typically only measured and described in one or two dimensions, the use of differentially corrected GPS with ADCPs provides a fully three-dimensional measurement of the magnitude and direction of the water column at such structures. The measurement of these flow disturbances in a field setting also captures the natural pulsations of river flow that cannot be easily quantified or modeled by numerical simulations or flumes. Several examples of measured three-dimensional flow conditions at bridge sites throughout Alaska are presented. The bias introduced to the bottom-track measurement is being investigated as a surrogate measurement of bedload transport. By fixing the position of the ADCP for a known period of time the apparent velocity of the streambed at that position can be determined. Initial results and comparison to traditionally measured bedload values are presented. These initial results and those by other researchers are helping to determine a direction for further research of noncontact measurements of sediment transport. Copyright ASCE 2005.

Conaway, J.S.

2005-01-01

375

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

NASA Astrophysics Data System (ADS)

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

Manga, Michael; Patel, Ameeta; Dufek, Josef

2011-04-01

376

From computing with numbers to computing with words-from manipulation of measurements to manipulation of perceptions  

NASA Astrophysics Data System (ADS)

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 which 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 which 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 underachivements 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, or CTP for short, is based on the methodology of computing with words (CW). In CTP, words play the role of labels of perceptions and, more generally, perceptions are expressed as propositions in a natural language. CW-based techniques are employed to translate propositions expressed in a natural language into what is called the Generalized Constraint Language (GCL). In this language, the meaning of a proposition is expressed as a generalized constraint, X isr R, where X is the constrained variable, R is the constraining relation and isr is a variable copula in which r is a variable whose value defines the way in which R constrains X. Among the basic types of constraints are: possibilistic, veristic, probabilistic, random set, Pawlak singing then the emphasis is put on the action aspect, while if we want to say that the singing is loud then the emphasis is on the sound, which is treated as a thing since one hears it. The crucial point is that one seems to be forced to make such a distinction, as assists the determination of structure, but the origin of this distinction is probably related to the different ways actions and objects are represented

Zadeh, Lotfi A.

2001-06-01

377

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

378

TRANSPORTATION TRANSPORTATION  

E-print Network

TEXASTRANS TEXAS TRANSPORTATION HALL HONOR OF HALL HONOR OF TEXASTRAN HALL HONOR OF TEXASTRAN HALL HONOR OF Inductees #12;2 TEXAS TRANSPORTATION HALL HONOR OF L NOR OF Texas is recognized as having one in supporting the economic development of the state and in providing Texans a high quality of life. The creation

379

Measurements of Aerodynamic Heat Transfer and Boundary-Layer Transition on a 15 deg. Cone in Free Flight at Supersonic Mach Numbers up to 5.2  

NASA Technical Reports Server (NTRS)

Measurements of aerodynamic heat transfer have been made at several stations on the 15 deg total-angle conical nose of a rocket-propelled model in free flight at Mach numbers up to 5.2. Data are presented for a range of local Mach number just outside the boundary layer from 1.40 to 4.65 and a range of local Reynolds number from 3.8 x 10(exp 6) to 46.5 x 10(exp 6), based on length from the nose tip to a measurement station. Laminar, transitional, and turbulent heat-transfer coefficients were measured. The laminar data were in agreement with laminar theory for cones, and the turbulent data agreed well with turbulent theory for cones using Reynolds number based on length from the nose tip. At a nearly constant ratio of wall to local static temperature of 1.2 the Reynolds number of transition increased from 14 x 10(exp 6) to 30 x 10(exp 6) as Mach number increased from 1.4 to 2.9 and then decreased to 17 x 10(exp 6) as Mach number increased to 3.7. At Mach numbers near 3.5, transition Reynolds numbers appeared to be independent of skin temperature at skin temperatures very cold with respect to adiabatic wall temperature. The transition Reynolds number was 17.7 x 10(exp 6) at a condition of Mach number and ratio of wall to local static temperature near that for which three-dimensional disturbance theory has been evaluated and has predicted laminar boundary-layer stability to very high Reynolds numbers (approximately 10(exp 12)).

Rumsey, Charles B.; Lee, Dorothy B.

1961-01-01

380

Simultaneous measurement of extracellular dopamine and dopamine transporter occupancy by cocaine analogs in squirrel monkeys  

PubMed Central

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 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; Stehouwer, Jeffrey; Goodman, Mark M.; Votaw, John R.; Carroll, F. I.; Howell, Leonard L.

2014-01-01

381

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

DOEpatents

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

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

2009-02-17

382

Transport measurements of UF/sub 5/ using a precision analysis for U/sup +4/  

SciTech Connect

Transport measurements of lower valent uranium halides require precise determinations of both total U and U/sup +4/. Dissolution of product from a nickel tube while maintaining the oxidation state of the uranium is required prior to determination of both total U and U/sup +4/ by a modified Davies-Gray analysis. Uranium/sup +4/ in the presence of U/sup +6/ can be easily titrated with standard dichromate and an overall precision of +-0.02 mg, at least between 4 and 80 mg in 100 ml of H/sub 3/PO/sub 4/. A sharp, rapid end-point is obtained by the addition of ferric ion, in addition to the vanadyl sulfate normally used as a catalyst. Nickel ion does not interfere, at least to levels of 4 mg/ml. (Al, Nb, V, Si, and Mn do not normally interfere with the Davies-Gray determination of total U, but have not been investigated).

Jarabek, R.J.

1984-04-02

383

Photon-number distributions of twin beams generated in spontaneous parametric down-conversion and measured by an intensified CCD camera  

NASA Astrophysics Data System (ADS)

The measurement of photon-number statistics of fields composed of photon pairs, generated in spontaneous parametric down-conversion and detected by an intensified charge-coupled device (iCCD) camera, is described. Final quantum detection efficiencies, electronic noises, finite numbers of detector pixels, transverse intensity spatial profiles of the detected beams, as well as losses of single photons from a pair are taken into account in a developed general theory of photon-number detection. The measured data provided by an iCCD camera with single-photon detection sensitivity are analyzed along the developed theory. Joint signal-idler photon-number distributions are recovered using the reconstruction method based on the principle of maximum likelihood. The range of applicability of the method is discussed. The reconstructed joint signal-idler photon-number distribution is compared with that obtained by a method that uses superposition of signal and noise and minimizes photoelectron entropy. Statistics of the reconstructed fields are identified to be multimode Gaussian. Elements of the measured as well as the reconstructed joint signal-idler photon-number distributions violate classical inequalities. Sub-shot-noise correlations in the difference of the signal and idler photon numbers as well as partial suppression of odd elements in the distribution of the sum of signal and idler photon numbers are observed.

Pe?ina, Jan, Jr.; Hamar, Martin; Michálek, Václav; Haderka, Ond?ej

2012-02-01

384

Photon-number distributions of twin beams generated in spontaneous parametric down-conversion and measured by an intensified CCD camera  

E-print Network

The measurement of photon-number statistics of fields composed of photon pairs, generated in spontaneous parametric down-conversion and detected by an intensified CCD camera is described. Final quantum detection efficiencies, electronic noises, finite numbers of detector pixels, transverse intensity spatial profiles of the detected beams as well as losses of single photons from a pair are taken into account in a developed general theory of photon-number detection. The measured data provided by an iCCD camera with single-photon detection sensitivity are analyzed along the developed theory. Joint signal-idler photon-number distributions are recovered using the reconstruction method based on the principle of maximum likelihood. The range of applicability of the method is discussed. The reconstructed joint signal-idler photon-number distribution is compared with that obtained by a method that uses superposition of signal and noise and minimizes photoelectron entropy. Statistics of the reconstructed fields are identified to be multi-mode Gaussian. Elements of the measured as well as the reconstructed joint signal-idler photon-number distributions violate classical inequalities. Sub-shot-noise correlations in the difference of the signal and idler photon numbers as well as partial suppression of odd elements in the distribution of the sum of signal and idler photon numbers are observed.

Jan Perina Jr; Ondrej Haderka; Martin Hamar; Vaclav Michalek

2012-02-07

385

Measurement of fuel mixing and transport processes in gas turbine combustion  

NASA Astrophysics Data System (ADS)

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 have been developed, but not all have been applied to practical systems either under scaled or under actual conditions. With respect to gaseous mixing processes, planar laser-induced fluorescence (PLIF) based on acetone is now starting to be successfully applied to actual systems and conditions. In spray-fired systems, the need to discriminate between phases leads to considerable complication in delineating fuel-air mixing. Methods that focus on the discrete phase have successfully provided details relative to the droplets. These include phase Doppler interferometry (PDI), which is becoming ubiquitous in application to practical devices and under practical conditions. PDI is typically being applied to quantify droplet sizes, although the volume flux, which is relevant to fuel-air mixing, in practical systems is also being reported. In addition, PLIF strategies that focus upon the behaviour of the droplets are now being developed. However, PLIF strategies that can discriminate between phases either in the fuel or with respect to the liquid fuel and combustion air are also being developed. In terms of characterizing the vector fields associated with the mixing process, laser anemometry (LA), although it is tedious to apply, has proven reliable even in the presence of droplets. Newer methods such as DPIV and FRS have seen only limited application in practical systems but appear promising. In terms of scalar fields, LIF and PLIF have also been applied successfully to these systems, and examples of the measurements of concentrations of various radical species such as OH are found throughout the literature.

McDonell, V. G.; Samuelsen, G. S.

2000-07-01

386

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

USGS Publications Warehouse

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

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

2001-01-01

387

Addressing Sustainability in Transportation Systems: Definitions, Indicators, and Metrics  

Microsoft Academic Search

Addressing the sustainability of transportation systems is an important activity as evidenced by a growing number of initiatives around the world to define and measure sustainability in transportation planning and infrastructure provision. This paper reviews major initiatives in North America, Europe, and Oceania. The purpose is to characterize the emergent thinking on what constitutes transportation sustainability and how to measure

Christy Mihyeon Jeon; Adjo Amekudzi

2005-01-01

388

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

389

New Measurements of the Li, Be, and B Isotopes as a Test of Cosmic Ray Transport Models  

NASA Technical Reports Server (NTRS)

Precise measurements of predominantly secondary cosmic-ray Li, Be, and B together with current well-measured production cross-sections for these isotopes help to improve our understanding of galactic cosmic ray propagation models. The Cosmic Ray Isotope Spectrometer (CRIS) on ACE has been measuring isotopic composition of cosmic rays since 1997 with high statistical precision. We present the isotopic abundances from CRIS and discuss these observations in the context of cosmic-ray transport models and previous cosmic-ray measurements.

deNolfo, Georgia A.; Yanasak, N. E.; Binns, W. R.; Cummings, A. C.; Davis, A. J.; George, J. S.; Hink, P. L.; Israel, M. H.; Leske, R. A.; Mewaldt, R. A.

2003-01-01

390

Transport spin polarization in SrRuO3 measured through point-contact Andreev reflection P. Raychaudhuri,1,2  

E-print Network

Transport spin polarization in SrRuO3 measured through point-contact Andreev reflection P of the 4d itinerant ferromagnet SrRuO3 in the ballistic limit of transport. The degree of transport spin oxide ferromagnets have complicated band structures with several bands crossing the Fermi surface

Raychaudhuri, Pratap

391

Measuring and predicting the transport of actinides and fission product contaminants in unsaturated prairie soil  

NASA Astrophysics Data System (ADS)

Soil samples have been taken in 2001 from the area of a 1951 release from an underground storage tank of 6.7 L of an aqueous solution of irradiated uranium (360 GBq). A simulation of the dispersion of the actinides and fission products was conducted in the laboratory using irradiated natural uranium, non-irradiated natural uranium and metal standards dissolved in acidic aqueous solutions and added to soil columns containing uncontaminated prairie soil. The lab soil columns were allowed 12 to 14 months for contaminant transport. Soil samples were analyzed using gamma-ray spectroscopy, neutron activation analysis (NAA) and liquid scintillation counting (LSC) to determine the elemental concentrations of U, Cs and Sr. Diffusion coefficients from the 50 year soil samples and the lab soil samples were determined. The measured diffusion coefficients from the field samples were 3.0 x 10-4 cm2 s-1 (Cs-137), 1.8 x 10-5 cm2 s-1 (U-238) and 2.6 x 10-3 cm2 s-1 (Sr-90) and the values determined from lab simulation were 5 x 10-6 cm 2 s-1 (Cs-137), 3 x 10-5 cm2 s-1 (U-238) and 1.9 x 10-5 cm 2 s-1 (Sr-90). The differences between the sets of diffusion coefficients can be attributed to differences in retardation effects, weather effects and changes in the soil characteristics when transporting, such as porosity. The analytical work showed that Cs-137 content of soil can be determined effectively using gamma-ray spectroscopy; U-238 content can be measured using NAA; and Sr-90 content can be measured using LSC. For non- and low-radioactive species, it was shown that both flame atomic absorption spectrometry (FAAS) and inductively-coupled plasma-mass spectrometry (ICP-MS) gave comparable results for Sr, Cs and Sm, with the average values ranging from 0.5 to 4.5 ppm of each other. The U-238 content results from NAA and from ICP-MS showed general agreement with an average difference of 81.3 ppm on samples having concentrations up to 988.2 ppm. The difference may have been due to matrix interference. It was determined through finite element modeling that 250 years after the 1951 release, the soil concentration of the three contaminant of U-238, Sr-90 and Cs-137 will be less than their respective soil clearance level values and therefore will not pose a long term environmental hazard. The fastest nuclide to reach the water table, at a depth of 45 m below the surface, at Suffield Site 27 was calculated to be Sr-90 after a period of 15,000 years. Therefore, it is not necessary to remove the subsurface soil at Site 27 for site decontamination but it is recommended that a "no-digging" policy, except for scientific research, be enforced at this site.

Sims, D. J.

392

A Comparison of Rome Observatory Sunspot Area and Sunspot Number Determinations With International Measures, 1958-1998  

NASA Technical Reports Server (NTRS)

Two changes in recording the sunspot record have occurred in recent years. First, in 1976, the longer-than-100-yr daily photographic record of the Royal Greenwich Observatory (RGO), used for determination of numbers and positions of sunspot groups and sunspot areas ended, and second, at the end of 1980, after more than 130 years, Zurich s Swiss Federal Observatory stopped providing daily sunspot numbers. To extend the sunspot record beyond 1976, use of United States Air Force/National Oceanic and Atmospheric Administration (USAF/NOAA) sunspot drawing observations from the Solar Optical Observing Network began in 1977, and the combined record of sunspot activity from RGO/USAF/NOAA was made accessible at http://science.nasa.gov/ssl/PAD/SOLAR/greenwch.htm. Also, in 1981, the task of providing daily sunspot numbers was taken up by the Royal Observatory of Belgium s Solar Influences and Data analysis Center, and the combined Zurich/International sunspot number database was made available at http://sidc.oma.be/index.php3. In this study, Rome Observatory 1958-1998 photographic records of sunspot areas, numbers of groups, and derived sunspot numbers are compared against same-day international values to determine relative behaviors and to evaluate whether any potential changes might have been introduced in the overall sunspot record, due to the aforementioned changes.

Wilson, Robert M.; Hathaway, David H.

2005-01-01

393

Measurements of Local Heat Transfer and Pressure on Six 2-Inch-Diameter Blunt Bodies at a Mach Number of 4.95 and at Reynolds Numbers Per Foot up to 81 x 10(exp 6)  

NASA Technical Reports Server (NTRS)

Measurements of the local heat transfer and pressure distribution have been made on six 2-inch-diameter, blunt, axially symmetric bodies in the Langley gas dynamics laboratory at a Mach number of 4.95 and at Reynolds numbers per foot up to 81 x 10(exp 6). During the investigation laminar flow was observed over a hemispherical-nosed body having a surface finish from 10 to 20 microinches at the highest test Reynolds number per foot (for this configuration) of 77.4 x 10(exp 6). Though it was repeatedly possible to measure completely laminar flow at this Reynolds number for the hemisphere, it was not possible to observe completely laminar flow on the flat-nosed body for similar conditions. The significance of this phenomenon is obscured by the observation that the effects of particle impacts on the surface in causing roughness were more pronounced on the flat-nosed body. For engineering purposes, a method developed by M. Richard Dennison while employed by Lockheed Aircraft Corporation appears to be a reasonable procedure for estimating turbulent heat transfer provided transition occurs at a forward location on the body. For rearward-transition locations, the method is much poorer for the hemispherical nose than for the flat nose. The pressures measured on the hemisphere agreed very well with those of the modified Newtonian theory, whereas the pressures on all other bodies, except on the flat-nosed body, were bracketed by modified Newtonian theory both with and without centrifugal forces. For the hemisphere, the stagnation-point velocity gradient agreed very well with Newtonian theory. The stagnation-point velocity gradient for the flat- nosed model was 0.31 of the value for the hemispherical-nosed model. If a Newtonian type of flow is assumed, the ratio 0.31 will be independent of Much number and real-gas effects.

Cooper, Morton; Mayo, Edward E.

1959-01-01

394

Structures and properties of sulfonated ionomers probed by transport and mechanical measurements: The role of solute activity  

NASA Astrophysics Data System (ADS)

This work is focused on advancing the understanding of the structures and properties of sulfonated ionomer membranes in the context of Polymer Electrolyte Membrane Fuel Cell applications by transport and mechanical measurements. Transport and mechanical properties are two critical elements of ionomer membranes that govern the performance and longevity of fuel cells. Additionally, transport and mechanical property measurements can also provide valuable information about the structure of the ionomer membranes. It is essential to develop a comprehensive understanding of them under well controlled environmental conditions. The mechanism of water transport through Nafion membranes was found to be governed by water diffusivity, swelling of the hydrophilic phase and the interfacial transport across membrane/vapor interface. A transport model incorporating these parameters was developed and successfully employed to resolve water activity profiles in the membrane and make quantitative predictions under steady state and dynamic conditions. Experimental results of diffusivity, volume of mixing and tortuosity also provided hints about the hydration shell structure around in the hydrophilic domains of Nafion. The alcohol sorption and transport was found to be qualitatively similar to the behavior of water and the quantitative differences were attributed to the difference in molecular size. The transport of alcohol water mixtures through Nafion displayed significant non-ideality which was connected to the abnormal swelling and incomplete mixing within the hydrophilic domains. The mechanical properties of several perfluoro-sulfonated ionomer (PFSI) membranes were studied as functions of temperature and solute activity. The thermal transition found between 60-100°C was described as an order-disorder transition of the ionic clusters. Water and other polar solutes were found to plasticize PFSI below the transition but stiffen PFSI above the transition. The stiffening effect was attributed to polar solute induced re-clustering of the ionic domains. Two hydrocarbon model ionomer SPS and SPEEK were studied to further understand the structural-property relationships of ionomers. Water sorption and proton conductivity were enhanced with increasing ion content but water content was independent of ion content and proton conductivity scaled with hydrophilic volume fraction. Water transport was dependent on diffusion and interfacial transport, both of which were affected by the size and shape of the hydrophilic domains.

Zhao, Qiao

395

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

396

Quantum dissipation theory and applications to quantum transport and quantum measurement in mesoscopic systems  

NASA Astrophysics Data System (ADS)

The thesis comprises two major themes of quantum statistical dynamics. One is the development of quantum dissipation theory (QDT). It covers the establishment of some basic relations of quantum statistical dynamics, the construction of several nonequivalent complete second-order formulations, and the development of exact QDT. Another is related to the applications of quantum statistical dynamics to a variety of research fields. In particular, unconventional but novel theories of the electron transfer in Debye solvents, quantum transport, and quantum measurement are developed on the basis of QDT formulations. The thesis is organized as follows. In Chapter 1, we present some background knowledge in relation to the aforementioned two themes of this thesis. The key quantity in QDT is the reduced density operator rho(t) ? trBrho T(t); i.e., the partial trace of the total system and bath composite rhoT(t) over the bath degrees of freedom. QDT governs the evolution of reduced density operator, where the effects of bath are treated in a quantum statistical manner. In principle, the reduced density operator contains all dynamics information of interest. However, the conventional quantum transport theory is formulated in terms of nonequilibrium Green's function. The newly emerging field of quantum measurement in relation to quantum information and quantum computing does exploit a sort of QDT formalism. Besides the background of the relevant theoretical development, some representative experiments on molecular nanojunctions are also briefly discussed. In chapter 2, we outline some basic (including new) relations that highlight several important issues on QDT. The content includes the background of nonequilibrium quantum statistical mechanics, the general description of the total composite Hamiltonian with stochastic system-bath interaction, a novel parameterization scheme for bath correlation functions, a newly developed exact theory of driven Brownian oscillator (DBO) systems, and its closely related solvation mode transformation of system-bath coupling Hamiltonian in general. The exact QDT of DBO systems is also used to clarify the validity of conventional QDT formulations that involve Markovian approximation. In Chapter 3, we develop three nonequivalent but all complete second-order QDT (CS-QDT) formulations. Two of them are of the conventional prescriptions in terms of time-local dissipation and memory kernel, respectively. The third one is called the correlated driving-dissipation equations of motion (CODDE). This novel CS-QDT combines the merits of the former two for its advantages in both the application and numerical implementation aspects. Also highlighted is the importance of correlated driving-dissipation effects on the dynamics of the reduced system. In Chapter 4, we construct an exact QDT formalism via the calculus on path integrals. The new theory aims at the efficient evaluation of non-Markovian dissipation beyond the weak system-bath interaction regime in the presence of time-dependent external field. By adopting exponential-like expansions for bath correlation function, hierarchical equations of motion formalism and continued fraction Liouville-space Green's function formalism are established. The latter will soon be used together with the Dyson equation technique for an efficient evaluation of non-perturbative reduced density matrix dynamics. The interplay between system-bath interaction strength, non-Markovian property, and the required level of hierarchy is also studied with the aid of simple spin-boson systems, together with the three proposed schemes to truncate the infinite hierarchy. In Chapter 5, we develop a nonperturbative theory of electron transfer (ET) in Debye solvents. The resulting exact and analytical rate expression is constructed on the basis of the aforementioned continued fraction Liouville-space Green's function formalism, together with the Dyson equation technique. Not only does it recover the celebrated Marcus' inversion and Kramers' turnover behaviors, the new theory also shows some disti

Cui, Ping

397

Measurement of Turbulence Decorrelation during Transport Barrier Evolution in a High Temperature Fusion Plasma  

SciTech Connect

A low power polychromatic beam of microwaves is used to diagnose the behavior of turbulent fluctuations in the core of the JT-60U tokamak during the evolution of the internal transport barrier. A continuous reduction in the size of turbulent structures is observed concomitant with the reduction of the density scale length during the evolution of the internal transport barrier. The density correlation length decreases to the order of the ion gyroradius, in contrast to the much longer scale lengths observed earlier in the discharge, while the density fluctuation level remain similar to the level before transport barrier formation.

R. Nazikian; K. Shinohara; G.J. Kramer; E. Valeo; K. Hill; T.S. Hahm; G. Rewoldt; S. Ide; Y. Koide; Y. Oyama; H. Shirai; W. Tang

2005-03-29

398

Aerosol Transport Questions Arising From Micro Pulse Lidar Measurements During MILAGRO  

NASA Astrophysics Data System (ADS)

A Micro Pulse Lidar (MPL) was operated by Argonne National Laboratory at the Universidad de Tecámac site (T1) during the MILAGRO field campaign in March 2006 in the environs of Mexico City. Located approximately 40 km north of the urban center of Mexico City, the T1 site was expected to observe the transport and evolution of aerosols as they moved out of the urban area on predominantly south winds. Because of the collocation of numerous other remote and in-situ sensors of aerosols, winds, temperatures and moisture. The MPL, operating at 0.527 microns, provides estimates of scattering in 15 m range (height) intervals, averaged over 10 sec between 200 m and (characteristically) 15 km, from which extinction profiles through and above the mixed layer can be calculated, mixed layer heights and evolution obtained and stratification and modification of aerosols observed. During the MILAGRO field campaign the growth of the mixed layer during daytime and the stratification of the atmosphere and subsequent aerosol layering were typical of previous campaigns and agreed well with structure observed by radar wind profiler, sodar, and radiosonde profiles. However, on many evenings very near sunset (1800 LT), a marked decrease in apparent aerosol concentration was observed through much of the depth of the mixed layer that persisted for 1-2 hours. Aerosol concentrations calculated with the CMAQ model coupled with MM5 wind fields will be evaluated with measured vertical profiles. Estimates of local radiative forcing for this site will be generated using MPL data set and model results.

Kotamarthi, R.; Coulter, R.; Pekour, M.

2007-12-01

399

Direct measurements of the ozone formation potential from dairy cattle emissions using a transportable smog chamber  

NASA Astrophysics Data System (ADS)

Tropospheric ozone continues to be an air pollution problem in the United States, particularly in California, Texas, and across the eastern seaboard. The obvious sources of ozone precursors have been largely controlled over the past several decades, leading to the critical examination of secondary sources. In particular, California has new air quality rules addressing agricultural sources of ozone precursors, including dairy farms. Some recent estimates predict that dairy cattle are second only to on-road vehicles as a leading source of ozone precursor emissions in California's San Joaquin Valley. The objective of this work was to directly measure the ozone formation potential from dairy housing. A transportable "smog" chamber was constructed and validated using organic gases known to be present in dairy emissions. The ozone formation potential of emissions from eight non-lactating dairy cows and their fresh waste was then directly evaluated in the field at a completely enclosed cow corral on the campus of the University of California, Davis. The results demonstrate that the majority of the ozone formation is explained by ethanol (EtOH) in the emissions from the dairy cows, not by acetone as previously thought. Ozone formation potential is generally small, with <20 ppb of ozone produced under typical conditions when EtOH concentrations were ˜200 ppb and NO x concentrations were ˜50 ppb. The results match our current understanding of atmospheric ozone formation potential, ruling out the possibility of unknown organic compounds in dairy emissions with significant ozone formation potential. Simulations carried out with a modified form of the Caltech Atmospheric Chemistry Mechanism verify that actual ozone formation from dairy emissions is much lower than what would be predicted using the current regulatory profiles. Based on these results, the ozone formation potential of emissions from dairy cattle in California seems to be lower than previously estimated.

Howard, Cody J.; Yang, Wenli; Green, Peter G.; Mitloehner, Frank; Malkina, Irina L.; Flocchini, Robert G.; Kleeman, Michael J.

400

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

SciTech Connect

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

Knudson, Marcus D.; Desjarlais, Michael Paul

2009-10-01

401

An in situ method to measure the longitudinal and transverse dispersion coefficients of solute transport in soil  

NASA Astrophysics Data System (ADS)

SummaryThe knowledge of hydraulic conductivity and solute transport parameters of top-soil is important in a variety of fields and their measurement has been an interest in both theory and practice. In this paper we present an in situ method to measure the longitudinal and transverse dispersion coefficients of solute movement by modifying the double-ring infiltrometer into a triple-ring infiltrometer. Water flow in the apparatus is controlled in one dimension and solute movement in three dimensions. The solute transport parameters can be measured simultaneously with the hydraulic conductivity. Analytical solutions are derived to describe the solute movement, and field experiment was carried out to calculate the solute parameters in homogeneous soil using a simple method developed based on the analytical solutions. Simulating results using these estimated parameters predict the observed breakthrough curves reasonably well.

Zhang, Xiaoxian; Qi, Xuebin; Zhou, Xinguo; Pang, Hongbin

2006-09-01

402

Toward exact number: young children use one-to-one correspondence to measure set identity but not numerical equality.  

PubMed

Exact integer concepts are fundamental to a wide array of human activities, but their origins are obscure. Some have proposed that children are endowed with a system of natural number concepts, whereas others have argued that children construct these concepts by mastering verbal counting or other numeric symbols. This debate remains unresolved, because it is difficult to test children's mastery of the logic of integer concepts without using symbols to enumerate large sets, and the symbols themselves could be a source of difficulty for children. Here, we introduce a new method, focusing on large quantities and avoiding the use of words or other symbols for numbers, to study children's understanding of an essential property underlying integer concepts: the relation of exact numerical equality. Children aged 32-36 months, who possessed no symbols for exact numbers beyond 4, were given one-to-one correspondence cues to help them track a set of puppets, and their enumeration of the set was assessed by a non-verbal manual search task. Children used one-to-one correspondence relations to reconstruct exact quantities in sets of 5 or 6 objects, as long as the elements forming the sets remained the same individuals. In contrast, they failed to track exact quantities when one element was added, removed, or substituted for another. These results suggest an alternative to both nativist and symbol-based constructivist theories of the development of natural number concepts: Before learning symbols for exact numbers, children have a partial understanding of the properties of exact numbers. PMID:24680885

Izard, Véronique; Streri, Arlette; Spelke, Elizabeth S

2014-07-01

403

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

E-print Network

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

Huchzermeyer, Erick Karl

2006-04-12

404

Physica E 34 (2006) 355358 Dynamics of nuclear spins appearing in transport measurements of an  

E-print Network

nonlinear transport between spin polarized edge channels is studied. The observed hysteresis of the I2V be calculated using the Landauer­Bu¨ ttiker multichannel formulae [5]. Assum- ing the absence of backscattering

Hohls, Frank

405

MIT commuter common : measuring and improving the transportation footprint of an urban institution  

E-print Network

This thesis develops a system for observing, visualizing, and understanding transportation behavior at the scale of an urban institution's entire population. In particular, the Massachusetts institute of Technology (MIT) ...

Winder, James Ira

2013-01-01