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1

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

PubMed Central

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.

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

2013-01-01

2

Measuring public transport accessibility  

Microsoft Academic Search

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

Andy Poole

2003-01-01

3

Measuring the approximate number system  

Microsoft Academic Search

Recent theories in numerical cognition propose the existence of an approximate number system (ANS) that supports the representation and processing of quantity information without symbols. It has been claimed that this system is present in infants, children, and adults, that it supports learning of symbolic mathematics, and that correctly harnessing the system during tuition will lead to educational benefits. Various

Camilla Gilmore; Nina Attridge; Matthew Inglis

2011-01-01

4

Electrolytic water-transport and ionic transport numbers  

Microsoft Academic Search

This paper gives the results of determinations of the electrolytic water-transport per faraday in the case of copper sulphate solutions of concentrations ranging from normal to 1.8-normal. The parchment diaphragm method has been employed; and difficulties experienced owing to the effect of diaphragm-polarization have been surmounted by adopting a special experimental procedure. The electrolytic water-transport per faraday remains constant with

H C Hepburn

1932-01-01

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

Bone Mass Measurement: What the Numbers Mean  

MedlinePLUS

... Bone Basics Bone Mass Measurement: What the Numbers Mean Publication available in: PDF (168 KB) Español Chinese ( ... Health and Osteoporosis Surgeon General's Report: What It Means to You Informe del Año 2004 del Cirujano ...

7

Measuring isotropic subsurface light transport.  

PubMed

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

Happel, Kathrin; Dörsam, Edgar; Urban, Philipp

2014-04-21

8

Bound on vertical heat transport at large Prandtl number  

NASA Astrophysics Data System (ADS)

We prove a new upper bound on the vertical heat transport in Rayleigh-Bénard convection of the form c Ra( under the assumption that the ratio of Prandtl number over Rayleigh number satisfies {Pr}/{Ra}?c0 where the non-dimensional constant c0 depends on the aspect ratio of the domain only. This new rigorous bound agrees with the (optimal) Ra bound (modulo logarithmic correction) on vertical heat transport for the infinite Prandtl number model for convection due to Constantin and Doering [P. Constantin, C.R. Doering, Infinite Prandtl number convection, J. Stat. Phys. 94 (1) (1999) 159-172] and Doering, Otto and Reznikoff [C.R. Doering, F. Otto, M.G. Reznikoff, Bounds on vertical heat transport for infinite Prandtl number Rayleigh-Bénard convection, J. Fluid Mech. 560 (2006) 229-241]. It also improves a uniform (in Prandtl number) Ra bound for the Nusselt number [P. Constantin, C.R. Doering, Heat transfer in convective turbulence, Nonlinearity 9 (1996) 1049-1060] in the case of large Prandtl number.

Wang, Xiaoming

2008-05-01

9

Reynolds Number Effects on a Supersonic Transport at Transonic Conditions  

NASA Technical Reports Server (NTRS)

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

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

2001-01-01

10

XCVII. Electrolytic water-transport and ionic hydration numbers  

Microsoft Academic Search

A review of the various methods that have been employed to determine the hydration of electrolytic ions in aqueous solution indicates that the most consistent results have been obtained from those methods which are based upon the measurement of the amount of water transported with the ions during electrolysis. The author concludes that the most convenient of the latter methods

H. C. Hepburn

1938-01-01

11

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

12

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

PubMed Central

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

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

2009-01-01

13

Economic Competitiveness: Performance Measures for Transportation.  

National Technical Information Service (NTIS)

The New York State Department of Transportation (NYSDOT) is developing a comprehensive set of measures that link investments in transportation to the general economic performance of the New York State Economy. The agency would like to understand in partic...

J. Berechman J. R. Peters R. E. Paaswell

2008-01-01

14

Skin Friction Measurements at Transonic Mach Numbers.  

National Technical Information Service (NTIS)

The skin friction of a body of revolution was determined from (1) embedded wire gage data and (2) the difference between balance-measured total drag and the integrated pressure force. Additional data were obtained from model mounted Preston tubes and boun...

C. L. Smith

1979-01-01

15

Measuring Argumentative Reasoning: What's behind the Numbers?  

ERIC Educational Resources Information Center

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

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

2009-01-01

16

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

PubMed

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

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

2013-01-01

17

Potential effects of public transport planning measures  

Microsoft Academic Search

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

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

2007-01-01

18

Transungual iontophoresis of lithium and sodium: effect of pH and co-ion competition on cationic transport numbers.  

PubMed

Iontophoresis has been proposed as an alternative method to deliver drugs into and across the nail plate. However, the knowledge about the rules governing transungual iontophoretic transport numbers is still uncomplete. This work investigated the iontophoretic and passive transungual fluxes of sodium and lithium and the effect of pH and co-ion competition on the cations' transport numbers. The objective was to further investigate whether nails show cation permselectivity at physiological pH and to improve our understanding of transport numbers during transungual iontophoresis. The donor solutions comprised the single ion and binary mixtures of the two cations at different pH. Sodium and lithium iontophoretic fluxes showed low inter-nail variability and were significantly greater than passive fluxes. Cationic transport numbers clearly increased as the pH was sequentially raised from 4.0 to 5.0 and then to 7.0, in agreement with a net negative charge of the human nails at physiological pH. Sodium transport number was maximal when the ion was formulated as a single ion (absence of competing co-ions) and decreased as the molar fraction of lithium was increased in the vehicle. The magnitude of the transport numbers measured and their response to changes in the cations' molar fraction and pH in the donor solution were remarkably similar to those observed during the transdermal iontophoresis. The ratio of lithium and sodium transport numbers was directly proportional to their relative concentration ratios; the proportionality constant being remarkably similar in the 4.0-7.0 pH range as well as to the ratio of the cations' aqueous mobilities. Another interesting similarity with transdermal iontophoresis was the existence of a cationic transport number threshold. On the whole, this work provided some key information about nail permselectivity and transungual transport numbers which will assist to formulate efficiently therapeutic compounds to be delivered iontophoretically into and across the nail plate. PMID:20153788

Dutet, Julie; Delgado-Charro, M Begoña

2010-06-01

19

Transportable calorimeter measurements of highly enriched uranium  

Microsoft Academic Search

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

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

1997-01-01

20

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

National Technical Information Service (NTIS)

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

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

2011-01-01

21

Transport measurements across single nanoparticles  

NASA Astrophysics Data System (ADS)

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

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

2013-03-01

22

Heat transport mechanisms of low Mach number turbulent channel flow with spanwise wall oscillation  

Microsoft Academic Search

Large eddy simulation (LES) of low Mach number compressible turbulent channel flow with spanwise wall oscillation (SWO) is\\u000a carried out. The flow field is analyzed with emphases laid on the heat transport as well as its relation with momentum transport.\\u000a When turbulent coherent structures are suppressed by SWO, the turbulent transports are significantly changed, however the\\u000a momentum and heat transports

Jian Fang; Li-Peng Lu; Liang Shao

2010-01-01

23

Measurement of Momentum Transport in Magnetic Turbulence  

NASA Astrophysics Data System (ADS)

Momentum transport in a hot accretion disk must be much faster than allowed by classical dissipation. The leading candidate for this anomalous transport is the magnetorotational instability (MRI), which produces magnetic turbulence [1]. Anomalous momentum transport is also observed in reversed field pinch (RFP) plasmas. Surprisingly, despite ? a few percent in MST plasmas, parallel pressure fluctuations correlated with magnetic fluctuations can produce momentum flux comparable to the radial momentum transport that occurs in magnetic relaxation events (sawteeth), thereby implying that kinetic effects are important for momentum transport in a turbulent magnetic field. This result was obtained using advanced interferometry and polarimetry techniques in the hot MST plasma core. Previous measurements in MST identified that both the Reynolds and Maxwell fluid stresses are also large (and oppositely directed) during these relaxation events. Thus multiple momentum transport mechanisms appear to be active in the RFP. We note that the parallel Maxwell stress is identically the Hall dynamo; the self-consistent coupling of momentum transport and dynamo has also been considered for accretion disks [2]. Supported by US DOE and NSF. [1] S.A. Balbus, J.F. Hawley, Rev. Mod. Phys., 70, 1 (1998). [2] F. Ebrahimi et al., Phys. Rev. Lett. 99, 075003 (2007).

Ding, W. X.; Brower, D. L.; Bergerson, W. F.; Lin, L.; Almagri, A.; Fiksel, G.; den Hartog, D. J.; Reusch, J. A.; Sarff, J. S.

2010-11-01

24

Transference number measurements on a hybrid polymer electrolyte  

Microsoft Academic Search

Two methods were used to measure the transference number of a hybrid polymer electrolyte at different salt concentrations. The hybrid polymer electrolyte was based on a radiation induced cross-linked polyether network with propylene carbonate in an interpenetrating liquid phase and LiAsF6 as electrolyte salt. One method for transference number measurements was based on the Hittorf method, which gave values ranging

Ib I. olsen; Rene Koksbang; Eivind Skou

1995-01-01

25

Determination of. epsilon. ,. beta. ,. alpha. from an arbitrary number of beam size measurements  

SciTech Connect

This note describes how the emittance {epsilon} and the betatron functions {beta} and {alpha} of a beam in an uncoupled high energy linac or transport line are extracted from an arbitrary number ({ge}3) of beam size measurements separated by various betatron phase advances. It is assumed that the beam sizes have no contributions from dispersion, intentional or otherwise.

Seeman, J.

1990-04-23

26

Florida Current volume transports from voltage measurements  

SciTech Connect

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

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

1985-01-18

27

Gefluegelte Raumtransporter: Das Problem der Stufenzahl (Winged Space Transporters: The Problem of the Number of Stages).  

National Technical Information Service (NTIS)

The number of stages and the recoverability of space transportation systems was studied. Comparison of the payload of present carriers with studies of partly reusable systems shows that modern materials and structures can lead to significantly better capa...

R. E. Lo D. M. Wolf

1986-01-01

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

Calibrating and Measuring Bedload Transport Using a Magnetic Detection System  

NASA Astrophysics Data System (ADS)

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

Rempel, J.; Hassan, M. A.

2004-12-01

30

Transport number and current–voltage of a cation exchange membrane equilibrated in aqueous and organic solutions  

Microsoft Academic Search

A physical-chemistry study of a Nafion 117 membrane is undertaken and a correlation between the transport number and current–voltage data of this cation exchange membrane is established. The current–voltage characteristics of the membrane are obtained with the voltamperometric technique, by means of two feed platinised titanium electrodes and two measuring silver–silver chloride electrodes. Previous measurements show that the membrane presents

H. Hamani; R. Bouamrane; M. Kameche; C. Innocent; Z. Derriche

2012-01-01

31

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

32

On the Number of Mather Measures of Lagrangian Systems  

NASA Astrophysics Data System (ADS)

In 1996, Ricardo Ricardo Mañé discovered that Mather measures are in fact the minimizers of a “universal” infinite dimensional linear programming problem. This fundamental result has many applications, of which one of the most important is to the estimates of the generic number of Mather measures. Mañé obtained the first estimation of that sort by using finite dimensional approximations. Recently, we were able, with Gonzalo Contreras, to use this method of finite dimensional approximation in order to solve a conjecture of John Mather concerning the generic number of Mather measures for families of Lagrangian systems. In the present paper we obtain finer results in that direction by applying directly some classical tools of convex analysis to the infinite dimensional problem. We use a notion of countably rectifiable sets of finite codimension in Banach (and Frechet) spaces which may deserve independent interest.

Bernard, Patrick

2010-09-01

33

Heat transport mechanisms of low Mach number turbulent channel flow with spanwise wall oscillation  

NASA Astrophysics Data System (ADS)

Large eddy simulation (LES) of low Mach number compressible turbulent channel flow with spanwise wall oscillation (SWO) is carried out. The flow field is analyzed with emphases laid on the heat transport as well as its relation with momentum transport. When turbulent coherent structures are suppressed by SWO, the turbulent transports are significantly changed, however the momentum and heat transports change in the same manner, which gives the evidence of inherently consistent transport mechanisms between momentum and heat in turbulent boundary layers. The Reynolds analogies of all the flow cases are quite good, which confirms again the fact that the transport mechanisms of momentum and heat are consistent, which gives theoretical support for controlling the wall heat flux control by using the drag reducing techniques.

Fang, Jian; Lu, Li-Peng; Shao, Liang

2010-06-01

34

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

35

Transport number of sodium ions in water-saturated, compacted Na-montmorillonite  

NASA Astrophysics Data System (ADS)

Diffusion of radionuclides in bentonite buffer material has been studied by many researchers. The nuclides in a form of ion diffuse in the bentonite satisfying electro-neutrality. It is important to examine major charge carriers as a possible counter ion for understanding the diffusion behavior in the bentonite. In this study, transport numbers of Na + ions, which are the major exchangeable cations in the sodium montmorillonite, which is the major mineral of bentonite, were experimentally determined as a function of dry density by a moving boundary method, using electromigration and electro-osmosis in the montmorillonite. The transport numbers were determined based on the electromigration of the Na + ions, because the contribution of the electro-osmosis to the migration of the cations is considered to be negligible. The effect of pore water ionic strength in the montmorillonite on the transport number was also examined. It was found that the transport numbers did not depend on the dry density and were nearly equal to 1. Therefore, the Na + ions behave as the predominant charge carrier in the montmorillonite. When salinity was increased up to 0.5 M, the transport numbers decreased down to 0.8. This suggests that the major part of the charge was carried by the Na + ions but the contribution of other ions to the charge carrier increased gradually with increase of the ionic strength.

Higashihara, Tomohiro; Kinoshita, Kumiko; Akagi, Yorimasa; Sato, Seichi; Kozaki, Tamotsu

36

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

37

Estimating the theoretical semivariogram from finite numbers of measurements  

USGS Publications Warehouse

We investigate from a theoretical basis the impacts of the number, location, and correlation among measurement points on the quality of an estimate of the semivariogram. The unbiased nature of the semivariogram estimator ??/(r) is first established for a general random process Z(x). The variance of ??z(r) is then derived as a function of the sampling parameters (the number of measurements and their locations). In applying this function to the case of estimating the semivariograms of the transmissivity and the hydraulic head field, it is shown that the estimation error depends on the number of the data pairs, the correlation among the data pairs (which, in turn, are determined by the form of the underlying semivariogram ??(r)), the relative locations of the data pairs, and the separation distance at which the semivariogram is to be estimated. Thus design of an optimal sampling program for semivariogram estimation should include consideration of each of these factors. Further, the function derived for the variance of ??z(r) is useful in determining the reliability of a semivariogram developed from a previously established sampling design.

Zheng, L.; Silliman, S. E.

2000-01-01

38

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

NASA Astrophysics Data System (ADS)

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

Vitanov, Nikolay K.

2003-02-01

39

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

NASA Technical Reports Server (NTRS)

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

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

2001-01-01

40

Automatic trajectory measurement of large numbers of crowded objects  

NASA Astrophysics Data System (ADS)

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

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

2013-06-01

41

Mass and heat transport in strongly time-dependent thermal convection at infinite prandtl number  

Microsoft Academic Search

We have studied heat and mass transport in two-dimensional, infinite Prandtl number, incompressible thermal convection for a range of Rayleigh numbers (Ra), between 10 and 10, and two different aspect-ratio boxes, between 1·8 and 10. This study has been motivated by recent developments in studying the transition from weak to strong turbulence in thermal convection. We have employed a two-dimensional

Ulrich Hansen; David A. Yuen; Sherri E. Kroening

1992-01-01

42

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

43

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

Code of Federal Regulations, 2013 CFR

...system for Government transportation documents? Yes, GSA will maintain a numbering system for GBLs and GTRs. For commercial TDs, each agency must create a unique numbering system to account for and prevent duplicate numbers. The GSA Audit Division...

2013-07-01

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

Rapid, Portable Voltammetric Techniques for Performing Antioxidant, Total Acid Number (TAN) and Total Base Number (TBN) Measurements.  

National Technical Information Service (NTIS)

This paper describes rapid voltammetric techniques for determining the antioxidant, total acid number (TAN), and total base number (TBN) measurements of a wide variety of oils and fluids. The voltammetric techniques require less than 1 milliliter (mL) of ...

R. E. Kauffman

1996-01-01

46

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

NASA Technical Reports Server (NTRS)

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

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

2001-01-01

47

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

SciTech Connect

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

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

2007-12-03

48

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...

49

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...

50

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

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

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

PubMed

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

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

2012-12-21

53

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

National Technical Information Service (NTIS)

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

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

2002-01-01

54

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

NASA Technical Reports Server (NTRS)

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

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

2002-01-01

55

Cationic transport number and conductivity in thorium dioxide: ThO/sub 2/. [1000 to 1500/sup 0/C  

SciTech Connect

The cationic transport number for thorium dioxide has been determined using thermal expansion measurements coupled with coulometric titration (dilato-coulometry). Polycrystalline ThO/sub 2/ was studied in the temperature range 1000 to 1500/sup 0/C, under oxygen partial pressures ranging from 1 to 10/sup -12/ atm. In air, t/sub Th/ approx. 5 x 10/sup -7/ at 1200/sup 0/C. Values for total conductivity are compared with data obtained by the Nernst--Einstein relation from the self-diffusion coefficient of Th in ThO/sub 2/.

Duclot, M.; Hammou, A.

1978-07-01

56

Mass Transport Measurement in 3D Porous Media for Carbon Sequestration  

NASA Astrophysics Data System (ADS)

To determine the storage potential for carbon sequestration strategies involving porous media, accurate determination of mass transport efficiency is required. We have made accurate measurements of mass transport in geometries similar to those relevant for sequestration, namely a gravitationally stable two layer system where the diffusion interface between the two phases is unstable. We use water and propylene glycol as the fluids in cells with cylindrical geometry. For a range of Rayleigh numbers between 150 and 5000, we find mass transport efficiency that is consistent with steady state thermal heat transport convection in porous media and with 2D mass transport in a Hele-Shaw geometry [1]. A transition from a high mass transport state to a lower mass transport state typically occurs between 4 and 6 convective times and is observed over the full Ra range. 10pt [1] S. Backhaus, K. Turitsyn, and R.E. Ecke, Physical Review Letters 106, 104501 (2011).

Ecke, Robert; Backhaus, Scott; Turitsyn, Konstantin

2011-11-01

57

Transport processes as manifested in satellite and lidar aerosol measurements  

NASA Technical Reports Server (NTRS)

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

Mccormick, M. P.

1985-01-01

58

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

59

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

60

Phase Measurement of Galvanneal Task JPL Task Order Number: RF152 Amendment Number: 543  

Microsoft Academic Search

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

Lynn Lowry; Beverly Tai

1995-01-01

61

Strongly intensive measures for transverse momentum and particle number fluctuations  

NASA Astrophysics Data System (ADS)

Strongly intensive measures ? [PT,N] and ? [PT,N] are used to study the event-by-event fluctuations of the transverse momentum PT and particle multiplicity N in nucleus-nucleus collisions. A special normalization for these fluctuation measures ensures that they are dimensionless and yields a common scale required for a quantitative comparison of fluctuations. In this paper basic properties of the ? [PT,N] and ? [PT,N] measures are tested within different phenomenological models using the Monte Carlo simulations (the so-called fast generators) and analytical solutions. The obtained results are helpful to elucidate the properties of the ? [PT,N] and ? [PT,N] measures.

Gorenstein, Mark I.; Grebieszkow, Katarzyna

2014-03-01

62

Sensitivity of transport aircraft performance and economics to advanced technology and cruise Mach number  

NASA Technical Reports Server (NTRS)

Sensitivity data for advanced technology transports has been systematically collected. This data has been generated in two separate studies. In the first of these, three nominal, or base point, vehicles designed to cruise at Mach numbers .85, .93, and .98, respectively, were defined. The effects on performance and economics of perturbations to basic parameters in the areas of structures, aerodynamics, and propulsion were then determined. In all cases, aircraft were sized to meet the same payload and range as the nominals. This sensitivity data may be used to assess the relative effects of technology changes. The second study was an assessment of the effect of cruise Mach number. Three families of aircraft were investigated in the Mach number range 0.70 to 0.98: straight wing aircraft from 0.70 to 0.80; sweptwing, non-area ruled aircraft from 0.80 to 0.95; and area ruled aircraft from 0.90 to 0.98. At each Mach number, the values of wing loading, aspect ratio, and bypass ratio which resulted in minimum gross takeoff weight were used. As part of the Mach number study, an assessment of the effect of increased fuel costs was made.

Ardema, M. D.

1974-01-01

63

Optical measurement techniques for high Reynolds number train investigations  

Microsoft Academic Search

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

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

2006-01-01

64

Experimental studies of Reynolds number dependence of turbulent mixing and transport  

NASA Astrophysics Data System (ADS)

Predicting turbulent mixing and transport remains a critical problem in industrial flows (combustion chambers, mixers, ventilation systems, etc.) and in the environment (smoke plumes, etc.). The mixing and transport processes are often a strong function of Reynolds number (Re) and yet there is a paucity of information on their Re dependence. We propose experiments of passive scalar mixing in isotropic grid turbulence whereby the Taylor Reynolds number (R(sub lambda)) will be varied from 30 to over 400 (60 less than R(sub l) less than 10,000). We will achieve the high R(sub lambda) by means of an active grid, which consists of grid bars with small wings that rotate and flap in a random way. We propose to study basic statistics (pdf, spectra, etc). of a homogeneous passive scalar (linear mean profile), as well as of an inhomogeneous scalar (passive line source) as a function of Re. There are many problems concerning the nature of the fine scale structure of a scalar (e.g., the existence of derivative skewness, the relation of the scalar spectrum to the velocity spectrum, and the rate of spreading of a contaminant plume), placing the similarity theory developed over the past 40 years in doubt, yet there is no information concerning its Reynolds number dependence in isotropic turbulence. The passive scalar will be temperature, although some experiments will be done using helium (which has a Schmidt number of 0.23). Particular emphasis will be placed on higher order statistics of both the signal and its derivative. Our experiments will be related to theory and modeling and to recent advances in direct numerical simulations. We will also do further work on mixing in a jet (also as a function of Re) and will relate this work to the (shearless) grid turbulence.

Warhaft, Z.

65

Transport coefficients for the shear dynamo problem at small Reynolds numbers  

SciTech Connect

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

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

2011-05-15

66

Numerical upper bounds on convective heat transport in a layer of fluid of finite Prandtl number: Confirmation of Howard's analytical asymptotic single-wave-number bound  

NASA Astrophysics Data System (ADS)

By means of the Howard-Busse method of the optimum theory of turbulence we investigate numerically the upper bounds on the Nusselt number in a heated-from-below horizontal layer of fluid of finite Prandtl number for the case of rigid boundaries. The bounds are obtained by the solutions of the Euler-Lagrange equations of a variational problem possessing up to three wave numbers. The obtained results are compared to the numerical results for the case of fluid layer with stress-free boundaries [N. K. Vitanov and F. H. Busse, ``Upper bounds on heat transport in a horizontal fluid layer with stress-free boundaries,'' ZAMP 48, 310 (1997)] as well as to the numerical and analytical asymptotic results obtained by Howard [``Heat transport by turbulent convection,'' J. Fluid Mech. 17, 405 (1963)], Busse [``On Howard's upper bound for heat transport by turbulent convection,'' J. Fluid Mech. 37, 457 (1969)], and Strauss [``On the upper bounding approach to thermal convection at moderate Rayleigh numbers, II. Rigid boundaries,'' Dyn. Atm. Oceans 1, 77 (1976)]. We show that for low and intermediate Rayleigh numbers the numerical bounds are positioned below the analytical asymptotic bounds obtained by Howard and Busse. For large Rayleigh numbers the numerical bounds tend to approach the analytical asymptotic bounds. We confirm numerically the bound obtained by Howard for the case of one-wave-number solution of the Euler-Lagrange equations. As the region of validity of the results of the analytical asymptotic theory for solutions of the Euler-Lagrange equations with two and three wave numbers lies in the area of very high Rayleigh numbers the values of the second and third wave numbers are different from their analytical asymptotic values for the values of the Rayleigh number reached by the numerical computation.

Vitanov, Nikolay K.

2005-10-01

67

The number comb for a soil physical properties dynamic measurement  

NASA Astrophysics Data System (ADS)

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

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

2012-04-01

68

Index Number Concepts, Measures and Decompositions of Productivity Growth  

Microsoft Academic Search

This paper explores the definitions and properties of total factor productivity growth (TFPG) indexes, focusing especially on the Paasche, Laspeyres, Fisher, Tornqvist, and implicit Tornqvist ones. These indexes can be evaluated from observable price and quantity data, and certain of these are shown to be measures of TFPG concepts and theoretical indexes that have been proposed in the literature. The

W. ERWIN DIEWERT; ALICE O. NAKAMURA

2003-01-01

69

Automatic Skid Number Evaluation Using Texture Laser Measurement  

Microsoft Academic Search

Skid resistance plays a very important role in highway construction, design, management, maintenance, road safety, and environment protection. In the past, evaluation of the skid resistance through the road texture on the highway and in the lab was not efficient, and traffic usually was disrupted. With the advent of the latest non-contact technologies of measurement, especially the use of laser,

Jiabin Xie; Richard Liu; Brian Michalk

2008-01-01

70

Performance Measures and Targets for Transportation Asset Management.  

National Technical Information Service (NTIS)

The two volumes of this report--Volume I, Research Report, and Volume II, Guide for Performance Measure Identification and Target Setting--will help transportation agencies apply the concepts of performance management to their asset management efforts. Vo...

2006-01-01

71

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

NASA Astrophysics Data System (ADS)

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

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

72

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

NASA Astrophysics Data System (ADS)

Biologically inspired hydrodynamic propulsion and maneuvering strategies promise the advancement of medical implants and novel robotic tools. We have chosen juvenile jellyfish as a model system for investigating fluid dynamics and morphological properties underlying fluid transport by an elastic system at intermediate Reynolds numbers. Recently we have described how natural variations in viscous forces are balanced by changes in jellyfish body shape (phenotypic plasticity), to the effect of facilitating efficient body-fluid interaction. Complementing these studies in our live model organisms, we are also engaged in engineering a synthetic jellyfish, that is, a rhythmically actuated elastomer capable of generating efficient feeding and propulsion currents. The main challenges here are (1) to derive a body shape and deformation suitable for effective fluid transport under physiological fluid conditions, (2) to understand the mechanical properties of actuator and elastomer to derive a design capable of the desired deformation, (3) to establish adequate 3D kinematics of power and recovery stroke, and (4) to evaluate the performance of the design.

Nawroth, Janna; Dabiri, John

2011-11-01

73

Transported acid aerosols measured in southern Ontario  

NASA Astrophysics Data System (ADS)

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

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

74

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

75

Transport Measurements on Individual Branched Nanostructures  

NASA Astrophysics Data System (ADS)

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

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

2005-03-01

76

Diagnosing ocean energy transports from earth radiation budget measurements  

NASA Technical Reports Server (NTRS)

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

Sohn, Byung-Ju; Smith, Eric A.

1992-01-01

77

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

78

Transitions in heat transport by turbulent convection at Rayleigh numbers up to 1015  

NASA Astrophysics Data System (ADS)

We describe a pressure vessel for conducting experiments in helium (He), air, nitrogen (N2) or sulfur hexafluoride (SF6) under pressures of up to 19 bars, and facilities for the study of Rayleigh-Bénard convection inside this pressure vessel. The convection cells, known as the high pressure convection facilities (HPCFs), can have interior heights up to L=2.3 m and diameters up to D=1.2 m. Measurements of the Nusselt number Nu for Rayleigh numbers Ra up to Ra*=4×1013 and a Prandtl number Prsime0.8 gave Nu~Ra?eff with ?effsime0.308. At Ra* there was a sharp transition to a new regime. The Nusselt number was continuous at Ra*, but the exponent characterizing its dependence on Ra changed suddenly to ?eff=0.25. Near Ra=Ra**sime3×1014, there was a further change in the Ra-dependence of Nu. A new state with ?effsime0.17 evolved and there was bistability of the ?eff=0.25 and the ?eff=0.17 branches.

Ahlers, Guenter; Funfschilling, Denis; Bodenschatz, Eberhard

2009-12-01

79

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

National Technical Information Service (NTIS)

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 (ATM...

J. H. Portsmouth

1992-01-01

80

Measurements and modeling of turbulent transport in the HSX stellarator  

NASA Astrophysics Data System (ADS)

Measurements of electron cyclotron resonance heated (ECRH) plasmas in HSX demonstrate a reduction in experimental electron thermal diffusivity in the core, consistent with that predicted by neoclassical theory due to quasihelical symmetry. However, the transport across most of the minor radius is anomalous. Because of the low electron collisionality, the trapped electron mode (TEM) instability is predicted to be the dominant turbulent transport mechanism. To assess this possibility, the Weiland model has been used to predict the linear stability and quasi-linear transport of HSX plasmas. This axisymmetric model, evaluated using the local curvature and trapped particle fraction in the outboard, low field, bad curvature region of HSX, is capable of reproducing the experimental transport within an order of magnitude. Localized edge turbulence measurements using Langmuir probes demonstrate the existence of fluctuation amplitudes consistent with mixing length arguments. The scale lengths, density-potential cross phases, and inferred growth rates are also in reasonable quantitative agreement with linear TEM predictions. The TEM growth rates, calculated more accurately for 3D HSX equilibria using the gyrokinetic code GS2, exhibit scaling with collisionality, density and temperature gradients, and trapped particle fraction, similar to that in tokamaks. The Weiland model, with local HSX geometry approximations, is shown to agree within 30% of the GS2 calculations for experimental parameters in HSX. One-dimensional transport simulations have been performed using the Weiland model in addition to neoclassical transport calculations. These simulations predict the energy confinement times within 10% of measured values. The predicted density and electron temperature profiles are in good agreement with measurements outside the inner 30% of the minor radius. The predictions inside this core region are sensitive to the radial electric field through both the neoclassical and anomalous transport models.

Guttenfelder, Walter Allen

81

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

82

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

83

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

84

Measurement of particle transport coefficients on Alcator C-Mod  

SciTech Connect

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

Luke, T.C.T.

1994-10-01

85

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

86

Charge transport measurements of vertically aligned carbon nanofibers  

NASA Astrophysics Data System (ADS)

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

Zhang, Lan

87

Measurements and Modeling of Turbulent Transport in the Tore Supra Tokamak  

SciTech Connect

This paper presents an overview of recent advances in modeling and measurements of turbulence in Tore Supra plasmas. Spatio-temporal properties of turbulence are discussed in relation with transport models. An explanation is proposed for the k{sup -3} decay of wave number spectra, which are observed by using both coherent laser scattering and Doppler reflectometry. Also the interplay between turbulence and flows has been investigated. It is shown that toroidal rotation results from a competition between neoclassical and turbulence flow generation. Finally a new method has been proposed to determine the transport coefficients of impurities. These coefficients are usually well above the neoclassical prediction.

Garbet, X.; Abiteboul, J.; Bourdelle, C.; Clairet, F.; Falchetto, G.; Fenzi, C.; Grandgirard, V.; Guirlet, R.; Hoang, G. T.; Sabot, R.; Sarazin, Y.; Segui, J. L.; Villegas, D. [CEA, IRFM, F-13108 Saint Paul Lez Durance (France); Benkadda, S.; Dubuit, N.; Futatani, S. [International Institute for Fusion Science, CNRS-Universite de Provence, Centre de St. Jerome, Case 321, 13397 Marseille Cedex 20 (France); Casati, A. [Ecole Polytechnique Federale de Lausanne (EPFL), Centre de Recherches en Physique des Plasmas, Association Euratom-Confederation Suisse, CH-1015 Lausanne (Switzerland); Guercan, Oe. D.; Hennequin, P.; Honore, C. [Laboratoire de Physique des Plasmas, CNRS-Ecole Polytechnique, 91128 Palaiseau Cedex (France)

2010-11-23

88

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

SciTech Connect

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

NONE

1995-08-01

89

Worldwide Transportation Directory: Essential Information on Agencies, Staff Contacts, Phone Numbers, and Addresses (1995 Edition).  

National Technical Information Service (NTIS)

The Directory was created to assist transportation data users, policy makers, planners, researchers, information specialists and others in locating essential information contacts and statistical agencies in different countries. It lists, by continent, 1,7...

S. Dresley B. S. Eversole M. A. Rossetti

1995-01-01

90

A rain splash transport equation assimilating field and laboratory measurements  

USGS Publications Warehouse

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

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

2010-01-01

91

Direct measurement of electrical transport through single DNA molecules  

NASA Astrophysics Data System (ADS)

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

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

2009-08-01

92

A method for the estimation of fissile mass by measuring the number of neutron signals within a specific time interval  

NASA Astrophysics Data System (ADS)

This paper presents a new method for fissile mass estimation by passive neutron interrogation. The method uses the stochastic transport equation to express the first three central moments (mean, variance and skewness) for the number of detected neutrons within a given time interval in terms of the fissile mass, the (?,n) rate and the multiplicity factor. Solving these three equations allows estimation of the fissile mass. As the primary validation of the method, it was implemented for several fissile mass measurements, which were conducted by the Nuclear Security Unit of the Joint Research Center (JRC) in Italy and by the Institute of Isotopes in Hungary.

Dubi, C.; Ridnick, T.; Israelashvili, I.; Bagi, J.; Huszti, J.

2012-05-01

93

North Aleutian Basin transportation methodology. Social and economic studies program technical report Number 102. Final report  

SciTech Connect

The principal objective of the report is to develop a methodology to evaluate potential changes in transportation service affected by possible OCS development of the North Aleutian Basin. The methodology consists of a set of forecasting and analysis procedures with associated assumptions about expected future events or activities, plus recommended standards for certain predetermined conditions. For each transportation mode, the methodology seeks to define and evaluate the incremental difference between conditions likely to occur with OCS activities and the conditions likely to occur with the proposed lease sale.

Not Available

1984-11-01

94

Local Transport Measurements on Graphene Using Scanning Tunneling Potentiometry  

NASA Astrophysics Data System (ADS)

Scanning tunneling potentiometry (STP) is a local transport measurement that was demonstrated some time ago, but has only recently been developed in a generally useful form. Near equilibrium, STP measures the electrochemical potential along a sample surface with near nanometer spatial resolution. With our newly developed STP system, we report preliminary results on few-layer graphene at room temperature and 4.2K. Room temperature STP data show a constant drift in the electric properties. At low temperature, however, our data show no such drift. Possible evidence for Landauer resistivity dipoles will be presented. Work supported by the AFOSR.

Wang, Weigang; Munakata, Ko; Rozler, Michael; Kidwingira, Francoise; Beasley, Malcolm

2009-03-01

95

Parallel Monte Carlo Particle Transport and the Quality of Random Number Generators: How Good is Good Enough?  

SciTech Connect

It might be assumed that use of a ''high-quality'' random number generator (RNG), producing a sequence of ''pseudo random'' numbers with a ''long'' repetition period, is crucial for producing unbiased results in Monte Carlo particle transport simulations. While several theoretical and empirical tests have been devised to check the quality (randomness and period) of an RNG, for many applications it is not clear what level of RNG quality is required to produce unbiased results. This paper explores the issue of RNG quality in the context of parallel, Monte Carlo transport simulations in order to determine how ''good'' is ''good enough''. This study employs the MERCURY Monte Carlo code, which incorporates the CNPRNG library for the generation of pseudo-random numbers via linear congruential generator (LCG) algorithms. The paper outlines the usage of random numbers during parallel MERCURY simulations, and then describes the source and criticality transport simulations which comprise the empirical basis of this study. A series of calculations for each test problem in which the quality of the RNG (period of the LCG) is varied provides the empirical basis for determining the minimum repetition period which may be employed without producing a bias in the mean integrated results.

Procassini, R J; Beck, B R

2004-12-07

96

Aperture Antenna Modeling by a Finite Number of Elemental Dipoles From Spherical Field Measurements  

Microsoft Academic Search

A method to determine a distribution of a finite number of elementary dipoles that reproduce the radiation behavior of the antenna under test (AUT) from truncated spherical field measurements is proposed. It is based on the substitution of the actual antenna by a finite number of equivalent infinitesimal dipoles (electric and magnetic), distributed over the antenna aperture. This equivalent set

Mohammed Serhir; Jean-Michel Geffrin; Amélie Litman; Philippe Besnier

2010-01-01

97

k-Space Image Correlation Spectroscopy: A Method for Accurate Transport Measurements Independent of Fluorophore Photophysics  

PubMed Central

We present the theory and application of reciprocal space image correlation spectroscopy (kICS). This technique measures the number density, diffusion coefficient, and velocity of fluorescently labeled macromolecules in a cell membrane imaged on a confocal, two-photon, or total internal reflection fluorescence microscope. In contrast to r-space correlation techniques, we show kICS can recover accurate dynamics even in the presence of complex fluorophore photobleaching and/or “blinking”. Furthermore, these quantities can be calculated without nonlinear curve fitting, or any knowledge of the beam radius of the exciting laser. The number densities calculated by kICS are less sensitive to spatial inhomogeneity of the fluorophore distribution than densities measured using image correlation spectroscopy. We use simulations as a proof-of-principle to show that number densities and transport coefficients can be extracted using this technique. We present calibration measurements with fluorescent microspheres imaged on a confocal microscope, which recover Stokes-Einstein diffusion coefficients, and flow velocities that agree with single particle tracking measurements. We also show the application of kICS to measurements of the transport dynamics of ?5-integrin/enhanced green fluorescent protein constructs in a transfected CHO cell imaged on a total internal reflection fluorescence microscope using charge-coupled device area detection.

Kolin, David L.; Ronis, David; Wiseman, Paul W.

2006-01-01

98

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

Microsoft Academic Search

The flow over a smooth sphere is examined in the Reynolds number range of 5.0 × 104 Re 5 via measurements of the fluctuating forces and particle image velocimetry measurements in a planar cut of the velocity field.\\u000a Comprehensive studies of the statistics and spectra of the forces are presented for a range of subcritical and supercritical\\u000a Reynolds numbers. While the subcritical lateral force

A. K. Norman; B. J. McKeon

99

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

100

Measurements of Turbulent Transport of Fast Ions in the LAPD  

NASA Astrophysics Data System (ADS)

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

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

2004-11-01

101

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

PubMed Central

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

Chiu, Chun-Huo; Chao, Anne

2014-01-01

102

Soliton-collision interferometer for the quantum nondemolition measurement of photon number: numerical results.  

PubMed

Using analytic theory and numerical experiments, we show that a quantum nondemolition measurement of the photon number of optical solitons in a single-mode optical fiber can be made. We describe the soliton-collision interferometer with which we propose to make this measurement and discuss simulations of the performance of this interferometer. PMID:19759769

Sakai, Y; Hawkins, R J; Friberg, S R

1990-02-15

103

Electron Temperature Measurements and Energy Transport in SSPX  

NASA Astrophysics Data System (ADS)

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

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

2007-11-01

104

A Study of the Magnitude of Transportation Noise Generation and Potential Abatement. Volume Ii. Measurement Criterion.  

National Technical Information Service (NTIS)

Evaluations of the effectiveness of transportation noise abatement require the use of a measure which relates individual and community reactions to transportation noise. Previous studies were examined to determine how well various measures predicted respo...

1970-01-01

105

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

NASA Astrophysics Data System (ADS)

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

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

2012-02-01

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

A mixed measure of content on the set of real numbers  

NASA Astrophysics Data System (ADS)

The counting measure applies only on countable subsets of the set of real numbers. On the other hand, the Lebesgue measure applies on any countable union of intervals but ignores countable subsets since it assigns to them a null weight indiscriminately. This paper proposes a measure of content which applies on finite unions of intervals and enables to differentiate finite sets. This measure of content is shown to be a Choquet capacity. Furthermore, extension onto the system of all subsets of the real number set is discussed and ideas for generalization to the multidimensional space are presented. A class of content-based measures of comparison is also suggested, along with a discussion of some of their basic properties.

Diatta, Jean

2003-02-01

108

Plasma sensor for high-bandwidth high Mach number velocity measurements  

Microsoft Academic Search

A working prototype of a miniature 2 MHz a.c. driven, weakly-ionized plasma anemometer for measurements at hypersonic Mach numbers has been developed. This device uses a plasma discharge between two encapsulated electrodes as the primary sensing element. The discharge has demonstrated sensitivity to mean and dynamic mass-flux variations up to Mach number = 1.4 and 200 kHz respectively. In principle,

Eric Matlis; Thomas Corke; Sivaram Gogineni

2004-01-01

109

Skin Friction and Transition Location Measurement on Supersonic Transport Models  

NASA Technical Reports Server (NTRS)

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

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

2000-01-01

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

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

NASA Technical Reports Server (NTRS)

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

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

1999-01-01

112

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

SciTech Connect

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

Kletzing, C. A.; Thuecks, D. J.; Skiff, F.; Bounds, S. R. [Department of Physics and Astronomy, University of Iowa 203 Van Allen Hall, Iowa City, Iowa, 52245 (United States); Vincena, S. [Department of Physics and Astronomy, University of California Los Angeles 1000 Veteran Avenue, Suite 15-70, Los Angeles, California, 90095-1696 (United States)

2010-03-05

113

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

Microsoft Academic Search

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

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

1994-01-01

114

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

PubMed

Quorum-sensing is the mechanism by which bacteria communicate and synchronize group behaviors. Quantitative information on parameters such as the copy number of particular quorum-sensing proteins should contribute strongly to understanding how the quorum-sensing network functions. Here, we show that the copy number of the master regulator protein LuxR in Vibrio harveyi can be determined in vivo by exploiting small-number fluctuations of the protein distribution when cells undergo division. When a cell divides, both its volume and LuxR protein copy number, N, are partitioned with slight asymmetries. We measured the distribution functions describing the partitioning of the protein fluorescence and the cell volume. The fluorescence distribution is found to narrow systematically as the LuxR population increases, whereas the volume partitioning is unchanged. Analyzing these changes statistically, we determined that N = 80-135 dimers at low cell density and 575 dimers at high cell density. In addition, we measured the static distribution of LuxR over a large (3000) clonal population. Combining the static and time-lapse experiments, we determine the magnitude of the Fano factor of the distribution. This technique has broad applicability as a general in vivo technique for measuring protein copy number and burst size. PMID:20441767

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

2010-05-19

115

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

SciTech Connect

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

Shen Yong; Zou Hongxin [Department of Physics, National University of Defense Technology, Changsha 410073 (China); Tian Liang [Department of Physics, National University of Defense Technology, Changsha 410073 (China); College of Optoelectronic Science and Engineering, National University of Defense Technology, Changsha 410073 (China)

2010-06-15

116

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

NASA Astrophysics Data System (ADS)

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

Shen, Yong; Tian, Liang; Zou, Hongxin

2010-06-01

117

Measurement of two-mode squeezing with photon number resolving multipixel detectors.  

PubMed

The measurement of the two-mode squeezed vacuum generated in an optical parametric amplifier (OPA) was performed with photon number resolving multipixel 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. PMID:22825148

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

2012-07-15

118

Vibrational Relaxation Times of a Number of Polyatomic Gases Derived from Measurements of Acoustic Absorption  

Microsoft Academic Search

The authors have described in a previous paper a method for deriving the acoustic absorption coefficient of gases from measurements of the decay time of a cylindrical resonator containing the gas in question. This technique has been applied to determine the relaxational contribution to the absorption at frequencies well below the dispersion region for a number of gases. The information

P. D. Edmonds; J. Lamb

1958-01-01

119

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

ERIC Educational Resources Information Center

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

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

2010-01-01

120

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

ERIC Educational Resources Information Center

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

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

2008-01-01

121

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

NASA Technical Reports Server (NTRS)

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

Lempert, Walter R.

1988-01-01

122

Measurements of turbulent flow in a channel at low Reynolds numbers  

Microsoft Academic Search

Normal and streamwise components of the velocity fields of turbulent flow in a channel at low Reynolds numbers have been measured with laser-Doppler techniques. The experiments duplicate the conditions used in current direct numerical simulations of channel flow, and good, but not exact, agreement is found for single-point moments through fourth order. In order to eliminate LDV velocity bias and

M. A. Niederschulte; R. J. Adrian; T. J. Hanratty

1990-01-01

123

Measurement of DNA copy number at microsatellite loci using quantitative PCR analysis.  

PubMed

This report describes the development and validation of quantitative microsatellite analysis (QuMA) for rapid measurement of relative DNA sequence copy number. In QuMA, the copy number of a test locus relative to a pooled reference is assessed using quantitative, real-time PCR amplification of loci carrying simple sequence repeats. Use of simple sequence repeats is advantageous because of the large numbers that are mapped precisely. In addition, all markers are informative because QuMA does not require that they be polymorphic. The utility of QuMA is demonstrated in assessment of the extent of deletions of chromosome 2 in leukemias arising in radiation-sensitive inbred SJL mice and in analysis of the association of increased copy number of the putative oncogene ZNF217 with reduced survival duration in ovarian cancer patients. PMID:11034080

Ginzinger, D G; Godfrey, T E; Nigro, J; Moore, D H; Suzuki, S; Pallavicini, M G; Gray, J W; Jensen, R H

2000-10-01

124

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

2014-05-28

125

Lidar measurements of Saharan dust transportation over Sofia  

NASA Astrophysics Data System (ADS)

Within the framework of the project "EARLINET-ASOS (European Aerosol Research Lidar Network - Advanced Sustainable Observation System)" Contract No 025991 of European Commission's Framework Program 6 (EC FP6) (http://www.earlinet.org), transportation of Saharan dust over Europe has been observed in the sky over Sofia, during the last week of May, 2008. This phenomena, predicted by the Atmospheric Modeling and Weather Forecasting Group of National Technical University of Athens (NTUA) (http://forecast.uoa.gr/) and the Forecast system of Barcelona Supercomputing Center (BSC) (http://www.bsc.es/projects/ earthscience/DREAM), was interesting with its relatively long-time existence and large scale of propagation over the continent. In this work, we present the results and some comments of the measurements of the atmospheric backscatter coefficient made in Sofia, using aerosol lidar with CuBrvapor laser.

Grigorov, I. V.; Kolarov, G. V.; Stoyanov, D. V.

2008-12-01

126

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

NASA Technical Reports Server (NTRS)

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

Bartlett, D. W.

1975-01-01

127

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

128

Measured field performance of CEBAF beam transport magnets  

NASA Astrophysics Data System (ADS)

The 2200 magnets used in the CEBAF beam transport system have each undergone testing of their magnetic fields. Results of these measurements will be reported. INT Bdl profiles measurements (with a precision of approximately equal to 10(exp -5)) for the 270 major solid-core dipoles used a multi-turn stretched wire with a reference magnet; the range of INT Bdl for a given (1, 2, or 3 m) dipole family was +/-5 x 10(exp -4). The approximately 700 quadrupole magnets' INT B(n)dl (1 less than or equal to n less than or equal to 16, R = R(pole)) values were measured with an accuracy of 0.01% of the quadrupole field component using a multi-turn 'Halbach' bucked coil for 20% of the magnets and a reference magnet for all. They had (INT B(6)dl)/(INT B(2)dl) less than 0.03% R (pole) and (INT B(10)dl)/(INT B(2)dl) less than 0.2% R(pole).

Harwood, Leigh; Karn, Jefferey

1994-07-01

129

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

NASA Technical Reports Server (NTRS)

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

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

1992-01-01

130

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

National Technical Information Service (NTIS)

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

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

1977-01-01

131

Measurement of implanted helium particle transport by a flowing liquid lithium film  

NASA Astrophysics Data System (ADS)

Due to its low atomic number, low sputtering yield, high sputtered ion fraction and excellent thermal properties, liquid lithium has been proposed as a potential candidate for advanced plasma-facing components (PFC). Using a liquid material opens the possibility of a continuously flowing, self-regenerating plasma-facing surface with a small residence time. This would allow such component to handle very high heat loads that are expected. There are, however, multiple unanswered questions regarding how such a liquid PFC would interact with the plasma in the reactor. The issue of particle control is critical, and it can be a factor to determine the feasibility of these advanced concepts. Hydrogen and helium are important in this regard: hydrogen transport by a flowing PFC impacts the reactor fuel recycling regime and tritium inventory; helium transport can help quantify ash removal by the flowing PFC. The flowing liquid-metal retention experiment (FLIRE) was built at the University of Illinois to answer some of the questions regarding particle transport by flowing liquid films exposed to plasmas. Experimental results regarding helium transport by a flowing lithium film after irradiation with an energetic He ion beam are presented in this work. Retained fraction values up to 2% were measured for the experimental conditions, and the retention was found to increase linearly with implanted ion energy. A pure diffusion model was used to describe the helium transport by the Li film, and it was found that such model predicts a diffusion coefficient of (2.8 ± 0.6) × 10 -11 m 2/s, based on the experimental retention measurements. Preliminary evidence of long-term trapping of helium will also be presented.

Nieto, M.; Ruzic, D. N.; Olczak, W.; Stubbers, R.

2006-04-01

132

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

133

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

134

Vacuum chamber pressure effects on thrust measurements of low Reynolds number nozzles  

NASA Technical Reports Server (NTRS)

Tests were conducted to investigate the effect of vacuum facility pressure on the performance of small thruster nozzles. Thrust measurements of two converging-diverging nozzles with an area ratio of 140 and an orifice plate flowing unheated nitrogen and hydrogen were taken over a wide range of vacuum facility pressures and nozzle throat Reynolds numbers. In the Reynolds number range of 2200 to 12 000 there was no discernable viscous effect on thrust below an ambient to total pressure ratio of 1000. In nearly all cases, flow separation occurred at a pressure ratio of about 1000. This was the upper limit for obtaining an accurate thrust measurement for a conical nozzle with an area ratio of 140.

Sovey, J. S.; Penko, P. F.; Grisnik, S. P.; Whalen, M. V.

1985-01-01

135

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

PubMed Central

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

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

2012-01-01

136

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

PubMed

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

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

2012-06-01

137

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

138

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

139

In situ measurements of effective diameter and effective droplet number concentration  

NASA Astrophysics Data System (ADS)

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

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

1999-02-01

140

Higher Reynolds Number Measurements on a Flat-Plate Turbulent Boundary Layer in the NDF  

NASA Astrophysics Data System (ADS)

The recent two experiments of Osterlund and Hites (e.g., see Osterlund, Johansson and Nagib, Phys. Fluids, vol. 12, no. 9, p. 2360, 2000) are extended to Reynolds numbers based on momentum thickness exceeding 50,000. The present measurements are conducted on a flat plate in zero pressure gradient in the National Diagnostic Facility (NDF). As in our previous work, the wall shear stress is directly measured using oil-film interferometry and hot-wire anemometry is used to measure the velocity. Contrary to the recent conclusions of Barenblatt, Chorin and Prostokishin (Phys. Fluids, vol. 12, no. 9, p. 2159, 2000; and JFM, vol. 410, p. 263, 2000), the mean velocity distribution in the overlap region for these higher Reynolds number boundary layers continues to be very accurately described by the Reynolds-number-independent log law. As concluded by us at this meeting last year and in the recent note by Osterlund et al. (Phys. Fluids, vol. 12, no. 1, p. 1, 2000), the values of the log-law coefficients that best represent the data are ? = 0.38 and B = 4.1. We will also briefly comment on asymptotic analyses of turbulent boundary layer and channel flows with an emphasis on the wall region and the various ways of scaling the boundary-layer outer region.

Nagib, Hassan; Christophorou, Chris; Osterlund, Jens; Monkewitz, Peter

2000-11-01

141

Chloride transport across placental microvillous membranes measured by fluorescence  

SciTech Connect

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

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

1988-12-01

142

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

Code of Federal Regulations, 2010 CFR

...270 What are agency performance measures for transportation? (a) Agency performance measures are indicators...customers and doing your job. By tracking performance measures you can...or proven superior ability; (4) Take...

2010-07-01

143

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

Code of Federal Regulations, 2010 CFR

...270 What are agency performance measures for transportation? (a) Agency performance measures are indicators...customers and doing your job. By tracking performance measures you can...or proven superior ability; (4) Take...

2009-07-01

144

Measuring physical activity with pedometers in older adults with intellectual disability: reactivity and number of days.  

PubMed

The minimum number of days of pedometer monitoring needed to estimate valid average weekly step counts and reactivity was investigated for older adults with intellectual disability. Participants (N ?=? 268) with borderline to severe intellectual disability ages 50 years and older were instructed to wear a pedometer for 14 days. The outcome measure was steps per day. Reactivity was investigated with repeated measures analysis of variance, and monitoring frame was assessed by comparing combinations of days with average weekly step counts (with intraclass correlation coefficients [ICCs] and regression analyses). No reactivity was present. Any combination of 4 days resulted in ICCs of 0.96 or higher and 90% of explained variance. The study concludes that any 4 days of wearing a pedometer is sufficient to validly measure physical activity in older adults with intellectual disability. PMID:22861135

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

2012-08-01

145

Transport measurements of InSb nanowires with induced superconductivity  

NASA Astrophysics Data System (ADS)

We report transport measurements of InSb nanowires coupled to both superconducting (NbTiN) and normal (Au) leads. Local gate control allows the nanowire to be configured in three distinct regimes: as a QPC, as a quantum dot strongly coupled to the superconducting lead, and as a quantum dot weakly coupled to both leads. In the QPC regime, we investigate zero-bias anomalies over a wide range of density and magnetic field. In the strongly coupled dot regime, we observe Andreev bound states that split in a magnetic field due to the combination of large g-factor of InSb and large critical magnetic field of NbTiN. The discrete energy levels of the weakly coupled quantum dot are used as a spectroscopic probe of the density of states of induced superconductivity in the nanowire adjacent to the dot. The connection of these results to the search for Majorana fermions in semiconductor nanowires will be discussed. We acknowledge support from Microsoft Station Q.

Churchill, Hugh; Fatemi, Valla; Grove-Rasmussen, Kasper; Deng, Mingtang; Xu, Hongqi; Marcus, Charles

2013-03-01

146

Ozone Measurements and a 3D Chemical Transport Model  

NASA Technical Reports Server (NTRS)

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

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

2004-01-01

147

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

148

Direct Measurements of the Outer Membrane Stage of Ferric Enterobactin Transport  

PubMed Central

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

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

2010-01-01

149

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

150

Simple and Versatile Molecular Method of Copy-Number Measurement Using Cloned Competitors  

PubMed Central

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.

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

151

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

152

Flow disturbance measurements through a constricted tube at moderate Reynolds numbers.  

PubMed

Instantaneous velocities in the field distal to contoured axisymmetric stenoses were measured with a laser Doppler anemometer. Upstream flow conditions were steady and spanned a range of Reynolds numbers from 500 to 2000. Autocorrelation functions and spectra of the velocity were employed to describe the nature of fluid dynamic disturbances. Depending upon the degree of stenosis and the Reynolds number, the flow field contained disturbances of a discrete oscillation frequency, of a turbulent nature, or both. If turbulence was detected in a given experiment, it was always preceded upstream by velocity oscillations at discrete frequency arising from vortex shedding. For mild degrees of stenosis (50% area reduction or less) the intensity of flow disturbances was relatively low until the Reynolds number exceeded 1000, thus highlighting difficulties to be expected in employing flow disturbance detection as a diagnostic tool in the recognition of early atherosclerosis in major arteries. In view of the relatively high noise levels inherent in noninvasive Doppler ultrasound systems employed clinically, it seems unlikely that detection of stenosis of less than 50% area reduction is feasible unless the Reynolds numbers exceed 1000 or unless pulsatility introduces new unsteady flow features beyond those studied here. PMID:6671986

Ahmed, S A; Giddens, D P

1983-01-01

153

Qubit-photon interactions in a cavity: Measurement-induced dephasing and number splitting  

SciTech Connect

We theoretically study measurement-induced dephasing of a superconducting qubit in the circuit QED architecture and compare the results to those obtained experimentally by Schuster et al. [Phys. Rev. Lett. 94, 123602 (2005)]. Strong coupling of the qubit to the resonator leads to a significant ac Stark shift of the qubit transition frequency. As a result, quantum fluctuations in the photon number populating the resonator cause dephasing of the qubit. We find good agreement between the predicted line shape of the qubit spectrum and the experimental results. Furthermore, in the strongly dispersive limit, where the Stark shift per photon is large compared to the cavity decay rate and the qubit linewidth, we predict that the qubit spectrum will be split into multiple peaks, with each peak corresponding to a different number of photons in the cavity.

Gambetta, Jay; Schuster, D. I.; Frunzio, L.; Majer, J.; Devoret, M. H.; Girvin, S. M.; Schoelkopf, R. J. [Department of Applied Physics and Department of Physics, Yale University, New Haven, Connecticut 06520 (United States); Blais, Alexandre [Department of Applied Physics and Department of Physics, Yale University, New Haven, Connecticut 06520 (United States); Departement de Physique et Regroupement Quebecois sur les Materiaux de Pointe, Universite de Sherbrooke, Sherbrooke, Quebec, J1K 2R1 (Canada); Wallraff, A. [Department of Applied Physics and Department of Physics, Yale University, New Haven, Connecticut 06520 (United States); Department of Physics, ETH Zurich, CH-8093 Zurich (Switzerland)

2006-10-15

154

Improvement of Pulping Uniformity by Measurement of Single Fiber Kappa Number  

SciTech Connect

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

Richard R. Gustafson; James B. Callis

2001-11-20

155

Cryptographic random number generators for low-power distributed measurement system  

NASA Astrophysics Data System (ADS)

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

Czernik, Pawel; Olszyna, Jakub

2009-06-01

156

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

NASA Astrophysics Data System (ADS)

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

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

2010-06-01

157

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

Microsoft Academic Search

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

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

1995-01-01

158

The effective number density of galaxies for weak lensing measurements in the LSST project  

NASA Astrophysics Data System (ADS)

Future weak lensing surveys potentially hold the highest statistical power for constraining cosmological parameters compared to other cosmological probes. The statistical power of a weak lensing survey is determined by the sky coverage, the inverse of the noise in shear measurements and the galaxy number density. The combination of the latter two factors is often expressed in terms of neff - the `effective number density of galaxies used for weak lensing measurements'. In this work, we estimate neff for the Large Synoptic Survey Telescope (LSST) project, the most powerful ground-based lensing survey planned for the next two decades. We investigate how the following factors affect the resulting neff of the survey with detailed simulations: (1) survey time, (2) shear measurement algorithm, (3) algorithm for combining multiple exposures, (4) inclusion of data from multiple filter bands, (5) redshift distribution of the galaxies and (6) masking and blending. For the first time, we quantify in a general weak lensing analysis pipeline the sensitivity of neff to the above factors. We find that with current weak lensing algorithms, expected distributions of observing parameters, and all lensing data (r and i band, covering 18 000 degree2 of sky) for LSST, neff ? 37 arcmin-2 before considering blending and masking, neff ? 31 arcmin-2 when rejecting seriously blended galaxies and neff ? 26 arcmin-2 when considering an additional 15 per cent loss of galaxies due to masking. With future improvements in weak lensing algorithms, these values could be expected to increase by up to 20 per cent. Throughout the paper, we also stress the ways in which neff depends on our ability to understand and control systematic effects in the measurements.

Chang, C.; Jarvis, M.; Jain, B.; Kahn, S. M.; Kirkby, D.; Connolly, A.; Krughoff, S.; Peng, E.-H.; Peterson, J. R.

2013-09-01

159

A novel technique for measuring variations in DNA copy-number: competitive genomic polymerase chain reaction  

PubMed Central

Background Changes in genomic copy number occur in many human diseases including cancer. Characterization of these changes is important for both basic understanding and diagnosis of these diseases. Microarrays have recently become the standard technique and are commercially available. However, it is useful to have an affordable technique to complement them. Results We describe a novel polymerase chain reaction (PCR)-based technique, termed competitive genomic PCR (CGP). The main characteristic of CGP is that different adaptors are added to the sample and control genomic DNAs after appropriate restriction enzyme digestion. These adaptor-supplemented DNAs are subjected to competitive PCR using an adaptor-primer and a locus-specific primer. The amplified products are then separated according to size differences between the adaptors. CGP eliminates the tedious steps inherent in quantitative PCR and achieves moderate throughput. Assays with different X chromosome numbers showed that it can provide accurate quantification. High-resolution analysis of neuroblastoma cell lines around the MYCN locus revealed novel junctions for amplification, which were not detected by a commercial array. Conclusion CGP is a moderate throughput technique for analyzing changes in genomic copy numbers. Because CGP can measure any genomic locus using PCR primers, it is especially useful for detailed analysis of a genomic region of interest.

Iwao-Koizumi, Kyoko; Maekawa, Kazunori; Nakamura, Yohko; Saito, Sakae; Kawamoto, Shoko; Nakagawara, Akira; Kato, Kikuya

2007-01-01

160

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

161

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.

162

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

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

163

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

164

Measuring post-disaster transportation system performance: the 1995 Kobe earthquake in comparative perspective  

Microsoft Academic Search

Recent earthquake disasters have caused major damage to transportation networks, leading to significant economic disruption. While this suggests the need to evaluate total system performance in transportation risk assessment, in addition to examining the vulnerability of individual components such as bridges, no appropriate measures currently exist. This paper develops post-disaster system performance measures and applies them to the urban rail

Stephanie E. Chang; Nobuoto Nojima

2001-01-01

165

Transport Characteristics From MultiComponent Approach in Magnetotail Plasma Measurements  

Microsoft Academic Search

Plasma measurements in the Earth's magnetotail have revealed occasional existence of multiple plasma components. It is uncertain whether the bulk plasma moments computed can truly represent the transport properties in such occasions. In this work, we examine the influence on the transport of plasma, magnetic field, and energy by the presence of multiple plasma components in Geotail plasma measurements. We

A. T. Lui; T. Hori; G. Ueno; T. Mukai

2004-01-01

166

Ab Initio Calculations for Helium: A Standard for Transport Property Measurements  

NASA Astrophysics Data System (ADS)

For helium, the accuracy of calculated transport properties and virial coefficients based on an accurate ab initio potential now exceeds that of the best measurements. The ab initio results should be used to calibrate measuring apparatus.

Aziz, Ronald A.; Janzen, Alec R.; Moldover, Michael R.

1995-02-01

167

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

168

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

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

169

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

170

Noninvasive Neutron Scattering Measurements Reveal Slower Cholesterol Transport in Model Lipid Membranes  

PubMed Central

Proper cholesterol transport is essential to healthy cellular activity and any abnormality can lead to several fatal diseases. However, complete understandings of cholesterol homeostasis in the cell remains elusive, partly due to the wide variability in reported values for intra- and intermembrane cholesterol transport rates. Here, we used time-resolved small-angle neutron scattering to measure cholesterol intermembrane exchange and intramembrane flipping rates, in situ, without recourse to any external fields or compounds. We found significantly slower transport kinetics than reported by previous studies, particularly for intramembrane flipping where our measured rates are several orders of magnitude slower. We unambiguously demonstrate that the presence of chemical tags and extraneous compounds employed in traditional kinetic measurements dramatically affect the system thermodynamics, accelerating cholesterol transport rates by an order of magnitude. To our knowledge, this work provides new insights into cholesterol transport process disorders, and challenges many of the underlying assumptions used in most cholesterol transport studies to date.

Garg, S.; Porcar, L.; Woodka, A.C.; Butler, P.D.; Perez-Salas, U.

2011-01-01

171

Apparatus for the measurement of radionuclide transport rates in rock cores  

SciTech Connect

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

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

1981-09-01

172

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

173

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

NASA Astrophysics Data System (ADS)

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

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

2010-05-01

174

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

PubMed

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

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

2010-05-01

175

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

NASA Astrophysics Data System (ADS)

Velocity and scalar concentration characteristics of low Reynolds number ( Re) neutrally buoyant turbulent round jets were studied using coupled particle image velocimetry and laser induced fluorescence. Experiments were conducted on a jet with a fully developed pipe exit profile at Re = 1,500 and Re = 4,000. Measurements were made in the far field (60 < x/ D < 80). Results show that the centerline velocity decay constant increases with Re and the virtual origin is located far from the jet exit. The Re does not have such an influence on the scalar concentration decay constant and scalar field virtual origin. Centerline turbulent intensities show evidence of becoming self-similar past x/ D ? 75 but the same is not observed in the scalar fluctuations. The latter are strongly influenced by the Re, increasing as entrainment of ambient flow on the jet axis increases as the flow approaches laminar conditions. Scalar fluxes showed a marked Re dependence as well. Results were used to estimate the turbulent Schmidt number which decreases as the Re decreases.

Zarruk, G. A.; Cowen, E. A.

2008-06-01

176

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

177

Measurement methods and accuracy in copy number variation: failure to replicate associations of beta-defensin copy number with Crohn's disease  

PubMed Central

The copy number variation in beta-defensin genes on human chromosome 8 has been proposed to underlie susceptibility to inflammatory disorders, but presents considerable challenges for accurate typing on the scale required for adequately powered case–control studies. In this work, we have used accurate methods of copy number typing based on the paralogue ratio test (PRT) to assess beta-defensin copy number in more than 1500 UK DNA samples including more than 1000 cases of Crohn's disease. A subset of 625 samples was typed using both PRT-based methods and standard real-time PCR methods, from which direct comparisons highlight potentially serious shortcomings of a real-time PCR assay for typing this variant. Comparing our PRT-based results with two previous studies based only on real-time PCR, we find no evidence to support the reported association of Crohn's disease with either low or high beta-defensin copy number; furthermore, it is noteworthy that there are disagreements between different studies on the observed frequency distribution of copy number states among European controls. We suggest safeguards to be adopted in assessing and reporting the accuracy of copy number measurement, with particular emphasis on integer clustering of results, to avoid reporting of spurious associations in future case–control studies.

Aldhous, Marian C.; Abu Bakar, Suhaili; Prescott, Natalie J.; Palla, Raquel; Soo, Kimberley; Mansfield, John C.; Mathew, Christopher G.; Satsangi, Jack; Armour, John A.L.

2010-01-01

178

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

PubMed Central

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

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

2011-01-01

179

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

180

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...

181

Continuous measurement of number concentrations and elemental composition of aerosol particles for a dust storm event in Beijing  

NASA Astrophysics Data System (ADS)

A continuous measurement of number size distributions and chemical composition of aerosol particles was conducted in Beijing in a dust storm event during 21-26 March 2001. The number concentration of coarse particles (>2 ?m) increased more significantly than fine particles (<2 ?m) during the dust storm due to dust weather, while the anthropogenic aerosols collected during the non-dust-storm period tended to be associated with fine particles. Elemental compositions were analyzed by using proton-induced X-ray emission (PIXE). The results show that 20 elements in the dust storm were much higher than in the non-dust-storm period. The calculated soil dust concentration during the dust storm was, on average, 251.8 ?g m-3, while it was only 52.1 ?g m-3 on non-dust-storm days. The enrichment factors for Mg, Al, P, K, Ca, Ti, Mn, Fe, Cl, Cu, Pb, and Zn show small variations between the dust storm and the non-dust-storm period, while those for Ca, Ni and Cr in the dust storm were much lower than those in the non-dust-storm period due to significant local emission sources. A high concentration and enrichment factor for S were observed during the dust storm, which implies that the dust particles were contaminated by aerosol particles from anthropogenic emissions during the long-range transport. A statistical analysis shows that the elemental composition of particles collected during the dust storm in Beijing were better correlated with those of desert soil colleted from desert regions in Inner Mongolia. Air mass back-trajectory analysis further confirmed that this dust storm event could be identified as streaks of dust plumes originating from Inner Mongolia.

Zhang, Renjian; Han, Zhiwei; Shen, Zhenxing; Cao, Junji

2008-01-01

182

High-speed quantum random number generation by measuring phase noise of a single-mode laser.  

PubMed

We present a high-speed random number generation scheme based on measuring the quantum phase noise of a single-mode laser operating at a low intensity level near the lasing threshold. A delayed self-heterodyning system has been developed to measure the random phase fluctuation. By actively stabilizing the phase of the interferometer, a random number generation rate of 500 Mbit/s has been demonstrated and the generated random numbers have passed all the DIEHARD tests. PMID:20125705

Qi, Bing; Chi, Yue-Meng; Lo, Hoi-Kwong; Qian, Li

2010-02-01

183

Photon-number statistics from the phase-averaged quadrature-field distribution: Theory and ultrafast measurement  

NASA Astrophysics Data System (ADS)

We prove that the photon-number distribution of an arbitrary single-mode optical state can be calculated directly from the phase-averaged quadrature amplitude distribution, measured using optical homodyne detection. We experimentally demonstrate the application of this result by measuring the ultrafast (subpicosecond), time-resolved photon-number statistics of a weak field from a pulsed diode laser. Also presented is a numerical calculation of the photon-number distribution of a quadrature-squeezed vacuum state.

Munroe, M.; Boggavarapu, D.; Anderson, M. E.; Raymer, M. G.

1995-08-01

184

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

NASA Technical Reports Server (NTRS)

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

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

1986-01-01

185

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

NASA Astrophysics Data System (ADS)

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

Fukiba, Katsuyoshi; Tsuboi, Nobuyuki; Kobayashi, Hiroaki

186

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

Microsoft Academic Search

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

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

2006-01-01

187

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

PubMed

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

Zadeh, L A

2001-04-01

188

Rural Rides--A Practical Handbook for Starting and Operating A Rural Public Transportation System. Program Aid Number 1215.  

ERIC Educational Resources Information Center

The transportation needs of the 30% of the population living in rural America, particularly those of the elderly, handicapped, poor, isolated, young, carless, and unemployed, are more critical than the needs of their counterparts in urban areas because of the lack of rural public transportation. Yet, only about 1% of the capitol federal investment…

Department of Agriculture, Washington, DC. Farmers Home Administration.

189

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

NASA Astrophysics Data System (ADS)

Helium ash production and transport have been measured in TFTR deuterium-tritium plasmas using charge-exchange recombination spectroscopy. The helium ash confinement time, including recycling effects, is 6-10 times the energy confinement time and is compatible with sustained ignition in a reactor. The ash confinement time is dominated by edge pumping rates rather than core transport. The measured evolution of the local thermal ash density is consistent with modeling based on previously measured helium transport coefficients and classical slowing down of the alpha particles.

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

1995-11-01

190

Parallel Measurement and Modeling of Transport in the DARHT II Beamline on ETA II.  

National Technical Information Service (NTIS)

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 ...

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

2005-01-01

191

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

ERIC Educational Resources Information Center

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

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

2008-01-01

192

Velocity measurements in a plane turbulent air jet at moderate Reynolds numbers  

Microsoft Academic Search

An experimental investigation of the moderate Reynolds number plane air jets was undertaken and the effect of the jet Reynolds number on the turbulent flow structure was determined. The Reynolds number, which was defined by the jet exit conditions, was varied between 1000 and 7000. Other initial conditions, such as the initial turbulence intensity, were kept constant throughout the experiments.

I. Namer; M. V. Ötügen

1988-01-01

193

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

194

[Concrete pain prevention measures regarding hospital internal transport in a cancer center].  

PubMed

Iatrogenic pain is a common problem for cancer patients, including those due to hospital internal transport. An original prospective study conducted in 2006 allowed risk factor identification, and from 2007, a pluri-annual progress plan was implemented. Its actions were systematically evaluated and all phases of transportation reconsidered: preparation, patient transport to and care in medicotechnical units. Measures applied to anticipate these pains help improve the quality of hospital care. All professionals involved in the patient transportation system need to be made aware of this and not only hospital porters. PMID:23823980

Nebbak, Jean-Marie; Vignozzi, Annick; Bussy, Catherine; Charleux, Diane; Laplanche, Agnès; Mathivon, Delphine; Di Palma, Mario

2013-01-01

195

Rectifying differences in transport, dynamic, and quasi-equilibrium measurements of critical current density  

NASA Astrophysics Data System (ADS)

The dependence of the critical current density (Jc) on electric field criteria (Ecr) is studied for high-quality YBCO (YBa2Cu3O7) thin films over the entire applied magnetic field (Ba) range. The quantitative model describing the Jc(Ba) dependence is compared and explained for the critical current densities obtained by different measurement techniques. Transport current and quasi-equilibrium magnetization measurement data can successfully be fitted by the model with appropriate electric field criteria. The dependence of the irreversibility field on the Ecr criterion can be obtained within the model. At the same time, the dynamic magnetization measurements of the Jc(Ba) curves strongly depend on instrumentally defined parameters, introducing inconsistencies in the experimental results. Therefore, the model calculations are able to explain the Jc(Ba) curves only if the instrumental vibrations affecting vortex behaviour are taken into account. However, the nature of the observed dependence on the vibration of the samples is unclear. Different frequencies of the sample vibrations have been investigated. It is revealed that if the frequency tends to zero, the Jc(Ba) curves are well described by the model. We have outlined a number of possibilities which may be responsible for the behaviour observed. However, none of the existing theories can explain the effect of the vibrations, which exponentially degrade the irreversibility field to a certain tampered Birr value at frequencies larger than ~=25 Hz.

Golovchanskiy, I. A.; Pan, A. V.; Shcherbakova, O. V.; Fedoseev, S. A.

2013-10-01

196

Photosynthetic activity and electron transport measurements using laser pump and probe technique.  

National Technical Information Service (NTIS)

The lidar fluorosensor apparatus available at ENEA (Italian Agency for New Technologies, Energy and the Environment) Frascati has been used for a series of laboratory measurements of the photosynthetic electron transport in maize plants. The system, recen...

R. Barbini F. Colao R. Fantoni A. Palucci S. Ribezzo

1994-01-01

197

Quantitative Research Regarding Performance Measures for Intermodal Freight Transportation. Executive Summary.  

National Technical Information Service (NTIS)

The primary objective of this study is to provide information relative to the development of a set of performance measures for intermodal freight transportation. To accomplish this objective, data was collected, processed, and analyzed on the basis of the...

1995-01-01

198

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

National Technical Information Service (NTIS)

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

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

1993-01-01

199

Membrane chloride transport measured using a chloride-sensitive fluorescent probe  

Microsoft Academic Search

Transport of chloride across cell membranes through exchange, cotransport, or conductive pathways is a subject of great biological importance. Current methods of measurement are restricted in their sensitivity, time resolution, and applicability. A new transport measurement technique has been developed on the basis of the fluorescence quenching by chloride of the dye 6-methoxy-N-(3-sulfopropyl)quinolinium (SPQ). SPQ fluorescence quenching by chloride is

Nicholas P. Illsley; Alan S. Verkman

1987-01-01

200

System for measuring passenger reaction to transportation-vehicle vibration  

NASA Technical Reports Server (NTRS)

Equipment is capable of measuring frequencies from 0 to 50 Hz and is portable, light, inexpensive, and easily adaptable to field operations. System could be used in situations where it is necessary to record simultaneously subject response to other types of physical measurement or stimuli, such as temperature, noise, or pressure.

Clevenson, S. A.; Dibble, A. C.; Lusby, T. K., Jr.; Scholl, H. F.; Stephens, D. G.

1974-01-01

201

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

SciTech Connect

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

Jia Peirong; Kofman, Jonathan; English, Chad

2007-06-01

202

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

SciTech Connect

Gas transport via pressure-driven permeation or via concentration-driven diffusion is a key step in the chemical vapor infiltration (CVI) process. This paper describes methods for the measurement of these properties for CVI preforms and partially infiltrated composites. Results are presented for Nicalon-fiber cloth layup preforms and composites, Nextel-fiber braid preforms and composites, and a Nicalon-fiber three-dimensional (3-D) weave composite. The permeability of Nicalon cloth layup preforms is strongly dependent on the packing density over the range of 29--40 vol% but is only weakly dependent on the orientation of the alternating cloth layers. The permeability of Nextel braid preforms is dependent on the thread count and the weight for cloths with similar construction and packing density. The gas permeability of the finer wave (6.3 tows/cm (16 tows/in.)) is approximately one-half that of the coarser weave (3.5 tows/cm (9 tows/in.)). Results are reported for a small number of infiltrated composites with Nextel fiber reinforcement. Attempts to mount a Nicalon-fiber 3-D weave preform specimen have been unsuccessful. Results for a small number of composite specimens with 3-D weave reinforcement are reported.

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

1998-05-01

203

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

204

Aperture antenna modelling by a finite number of elemental dipoles from truncated spherical field measurement: Experimental investigation  

Microsoft Academic Search

A method to determine a distribution of a finite number of elementary dipoles that reproduce the radiation behaviour of the antenna under test (AUT) from truncated spherical field measurements is proposed. It is based on the substitution of the actual antenna by a finite number of equivalent infinitesimal dipoles (electric and magnetic), distributed over the antenna aperture. This equivalent set

M. Serhir; J. M. Geffrin; A. Litman; N. Ribiere-Tharaud; P. Besnier

2010-01-01

205

Estimation of the number of frequencies and bandwidth for the surface measurement of soil moisture as a function of depth  

Microsoft Academic Search

The feasibility of obtaining estimates in situ of volumetric soil moisture as a function of depth using measurements of radio wave reflection at the soil surface at several discrete frequencies was demonstrated through computer simulation. By deriving empirical relationships between the number of frequencies, the frequency range, and the number of soil layers for which the soil moisture is estimated,

John R. Holdem; Richard B. Keam; Johann A. Schoonees

2000-01-01

206

Critical state and AC losses in multifilamentary BiSrCaCuO-2223/Ag tapes studied by transport and magnetic measurements  

NASA Astrophysics Data System (ADS)

AC losses in two multifilamentary BiSrCaCuO-2223/Ag tapes differing in number of filaments were determined by transport and magnetic measurements. In the latter, the AC field was directed perpendicularly to the wide side of the tape and the model of a superconducting strip was used in the calculations. Comparison of the experimental data with theoretical models confirmed that when the tape carries a transport AC current, strong electromagnetic coupling between filaments leads to non-uniform distribution of current among the individual filaments. On the contrary, the results of magnetic measurements were consistently explained only if we supposed a negligible electromagnetic coupling between filaments. This effect could explain the commonly observed discrepancy between AC transport and magnetic loss measurements. By taking this effect into account, the apparent lack of consistency in the Jc value of the superconductor derived from transport and magnetic experiments disappears.

Gömöry, F.; Gherardi, L.; Mele, R.; Morin, D.; Crotti, G.

1997-02-01

207

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

NASA Technical Reports Server (NTRS)

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

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

1992-01-01

208

On the estimation of tidal and subinertial alongshore water transport from onshore telluric field measurements  

NASA Astrophysics Data System (ADS)

Onshore measurements of telluric field oscillations have been used to estimate the water transport associated to tidal flow in the western Portuguese coast. The onshore E-W dipoles located at São Jacinto and Sines were calibrated by comparing the ocean modelled N-S shelf water transport originated by the main lunar tidal frequency and the corresponding onshore motionally tidal electric field. Calibration factors of 3.00×104 and 4.25×103 m3 s-1 for each mV km-1, with motionally induced origin, were estimated for São Jacinto and Sines, respectively. The results showed that it is possible to estimate the water transport from onshore measurements. The possibility of estimate subinertial alongshelf flow was also assessed, concluding that due to the lack of periodicities controlling that flow is not possible to establish a relationship between alongshelf transports and measured electric potential difference.

Marta-Almeida, Martinho; Santos, Fernando; Dubert, Jesus; Nolasco, Rita; Bernardo, Ivo; Soares, Antonio; Peliz, Alvaro; Dias, Joao

2010-05-01

209

Measurements of the critical Marangoni number of the laminar-oscillatory transition of thermocapillary convection in floating zones  

NASA Astrophysics Data System (ADS)

The critical Marangoni number of the transition point from laminar to oscillatory thermocapillary convection in a liquid bridge with free cylindrical surface (floating zone) is measured under microgravity. The critical Marangoni numbers of NaNO3-zones with 6 mm diameter and length 4.00 and 4.79 mm are compared with measurements under normal Earth gravity. Data on the dependence of the oscillation frequency on the Marangoni number are given. Frequency jumps and beat frequencies are found in microgravity and normal gravity.

Schwabe, D.; Scharmann, A.

1984-12-01

210

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

SciTech Connect

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

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

2012-05-15

211

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

212

Measuring performance of night-time interfacility transport service.  

PubMed

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

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

2012-08-01

213

Project Impact on Ultimate Performance Measures. Analytic Study Number One. Utah Alcohol Safety Action Project (ASAP).  

National Technical Information Service (NTIS)

The Utah ASAP significantly reduced the number of injury crashes occurring during high incidence time periods. It is found that alcohol related fatal crashes decreases at the end of ASAP operation; this is probably due to decreased reporting emphasis. No ...

R. Byrd

1977-01-01

214

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

NASA Astrophysics Data System (ADS)

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

Y?lmaz, Demet; Tur?ucu, Ahmet; Uzuno?lu, Zeynep; Korucu, Demet

2014-09-01

215

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

216

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

Microsoft Academic Search

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

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

2009-01-01

217

In-Vehicle Measurement of Particle Number Concentrations on School Buses Equipped with Diesel Retrofits  

Microsoft Academic Search

Many metropolitan school districts worldwide operate bus fleets with older diesel school buses. Emission reduction strategies\\u000a such as the diesel retrofits promise substantial reductions in particulate mass emissions for older diesel engines. Recent\\u000a studies suggest, however, that particle number concentration is a more important factor than particle mass in developing emissions\\u000a standards and predicting adverse health effects. In-vehicle particle number

Davyda M. Hammond; Melinda M. Lalor; Steven L. Jones

2007-01-01

218

MEASUREMENT OF LIGHT HYDROCARBONS AND OXIDANT TRANSPORT, HOUSTON AREA 1976  

EPA Science Inventory

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

219

Health Technology Assessment Reports 1986. Number 6. Dual Photon Absorptiometry for Measuring Bone Mineral Density.  

National Technical Information Service (NTIS)

Dual photon absorptiometry (DPA) is a noninvasive radiologic technique used to measure bone mineral density (BMD) in the lumbar spine and hip. With DPA the amount of bone mineral measured represents the total integrated mineral (cortical and trabecular) i...

M. Erlichman

1986-01-01

220

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

Microsoft Academic Search

The effect of a third-order fluid on the peristaltic transport in an asymmetric channel is studied. The wavelength of the peristaltic waves is assumed to be large compared to the varying channel width, whereas the wave amplitudes need not be small compared to the varying channel width. The channel asymmetry is produced by choosing the peristaltic wave train on the

Mohamed H. Haroun

2007-01-01

221

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

222

Magnetic Resonance Measurement of Scale Dependent Dynamics in Porous Media: Interplay of Structure and Transport  

NASA Astrophysics Data System (ADS)

Experimental measurements of anomalous transport are needed to further test and complement understanding of models and numerical simulations of transport in reactive porous media. Magnetic resonance microscopy (MRM) represents a powerful tool for acquiring useful data due to the noninvasive nature of the technique, which can measure time and length scale dependent displacement dynamics inside opaque porous media. Experimental results for a model site percolation system indicate a dynamical scaling of the super-diffusive hydrodynamic dispersion, in contrast to classic percolation scaling arguments which predict only geometric scaling, and serve as a template for the comparison of theory and MRM experiments. MRM measurements in bio-reactive porous media containing biofilms have previously been shown to be well described as a transition from normal transport in a homogeneous medium to anomalous transport in a heterogeneous medium [1]. Recent results indicate that the underlying porous media structure before biofilm growth can impact or control the transition of the dynamics during bioactivity. General ideas related to measurement of anomalous transport by MRM will be considered. 1. J.D. Seymour et al., Anomalous fluid transport in porous media induced by biofilm growth, Phys. Rev. Lett. 93 (2004) 198103.

Seymour, J. D.; Codd, S. L.

2008-12-01

223

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

224

Radiation transport measurements by X-ray scattering  

NASA Astrophysics Data System (ADS)

We have conducted x-ray scattering measurements on a radiatively-heated low density (0.2 g/cc) carbon foam. The foam is heated by a radiation cavity (hohlraum), which is driven by 6 to 9 kJ of laser energy at the Omega laser facility (University of Rochester). Using as a probe the 4.75 keV He-alpha line radiation produced by irradiating a Ti foil, we have recorded time-resolved spectrally dispersed 80 deg. scattered spectra with a high efficiency graphite Bragg crystal coupled to a framing camera. By fitting the measured Doppler-broadened and Compton red-shifted scattered spectra at various times after the end of the driving laser beams, we temporally resolve the electron temperature and ionization state progression as the radiation wave passes through the foam. In order to compare our results with radiation hydrodynamics simulations, we have also obtained flux-integrated measurements of the hohlraum emission (DANTE) for an estimate of the radiation temperature inside the cavity. Our results show peak foam electron temperatures Te ˜170 eV, with an average ionization state Zf ˜5.2, in agreement with LASNEX predictions. These EOS results are also of interest for understanding coupling of x-rays to capsule blow-off in indirect drive ICF.

Gregori, Gianluca; Hammer, J.; Dewald, E.; Glenzer, S. H.; Landen, O. L.

2004-11-01

225

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

NASA Technical Reports Server (NTRS)

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

Stephens, D. G.

1975-01-01

226

Nanopore unitary permeability measured by electrochemical and optical single transporter recording.  

PubMed

For the analysis of membrane transport processes two single molecule methods are available that differ profoundly in data acquisition principle, achievable information, and application range: the widely employed electrical single channel recording and the more recently established optical single transporter recording. In this study dense arrays of microscopic horizontal bilayer membranes between 0.8 microm and 50 microm in diameter were created in transparent foils containing either microholes or microcavities. Prototypic protein nanopores were formed in bilayer membranes by addition of Staphylococcus aureus alpha-hemolysin (alpha-HL). Microhole arrays were used to monitor the formation of bilayer membranes and single alpha-HL pores by confocal microscopy and electrical recording. Microcavity arrays were used to characterize the formation of bilayer membranes and the flux of fluorescent substrates and inorganic ions through single transporters by confocal microscopy. Thus, the unitary permeability of the alpha-HL pore was determined for calcein and Ca(2+) ions. The study paves the way for an amalgamation of electrical and optical single transporter recording. Electro-optical single transporter recording could provide so far unresolved kinetic data of a large number of cellular transporters, leading to an extension of the nanopore sensor approach to the single molecule analysis of peptide transport by translocases. PMID:15749773

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

2005-06-01

227

Measurement of Local Soil Water Flux during Field Solute Transport Experiments  

Microsoft Academic Search

port properties of the soil can be inversely determined by fitting a model to the measured breakthrough curves. calculated directly from the local solute mass flux. The methods as- Outflow concentration from a soil column is flux con- sume that water flow and solute transport are one-dimensional and centration and solute concentration measured by soil that TDR estimates of bulk

Bing Cheng Si; R. Gary Kachanoski

2003-01-01

228

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

NASA Technical Reports Server (NTRS)

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

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

1972-01-01

229

PIV measurements of water mist transport in a homogeneous turbulent flow past an obstacle  

Microsoft Academic Search

To obtain a better understanding of the physical processes involved in liquid suppressant transport in cluttered spaces, particle image velocimetry (PIV) measurements were carried out in the droplet-laden, grid-generated, homogeneous turbulent flow over both an unheated and heated cylinder, and a body-centered cube (BCC) arrangement of spheres. Transport of both water droplets and aerosol particles was characterized upstream and downstream

Cary Presser; George Papadopoulos; John F. Widmann

2006-01-01

230

Measuring the time needed for training a neural network based on the number of training steps  

Microsoft Academic Search

Artificial neural networks play an important role in robot programming by demonstration. In this paper we present a method for artificial neural network training. The main idea of this method is to train the artificial neural network with all of the data, before the current training step, and at a certain step the network is already trained a huge number

M. Stoica; G. A. Calangiu; F. Sisak

2010-01-01

231

MEASUREMENTS AND COMPUTATIONS OF FUEL DROPLET TRANSPORT IN TURBULENT FLOWS  

SciTech Connect

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

Joseph Katz and Omar Knio

2007-01-10

232

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

233

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

ERIC Educational Resources Information Center

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

Ericson, T. J.

1988-01-01

234

Measurement of dispersion numbers for 36 and 100% tri-isoamyl phosphate solvents equilibrated with aqueous nitric acid solutions  

Microsoft Academic Search

Dispersion number is a direct indication of the settling and coalescing property of solvent with the given aqueous system.\\u000a By dispersion number measurement, suitability of solvent can be characterized for post-mixing settling operations during solvent\\u000a extraction. Tri-isoamyl phosphate (TiAP) is being proposed as extractant, alternate to conventional extractant TBP for nuclear\\u000a solvent extraction processes. In this work, TiAP is characterized

M. Balamurugan; Shekhar Kumar; U. Kamachi Mudali; R. Natarajan

235

In-flight pressure distributions and skin-friction measurements on a subsonic transport high-lift wing section  

NASA Technical Reports Server (NTRS)

Flight experiments are being conducted as part of a multiphased subsonic transport high-lift research program for correlation with wind-tunnel and computational results. The NASA Langley Transport Systems Research Vehicle (B737-100 aircraft) is used to obtain in-flight flow characteristics at full-scale Reynolds numbers to contribute to the understanding of 3-D high-lift, multi-element flows including attachment-line transition and relaminarization, confluent boundary-layer development, and flow separation characteristics. Flight test results of pressure distributions and skin friction measurements were obtained for a full-chord wing section including the slat, main-wing, and triple-slotted, Fowler flap elements. Test conditions included a range of flap deflections, chord Reynolds numbers (10 to 21 million), and Mach numbers (0.16 to 0.40). Pressure distributions were obtained at 144 chordwise locations of a wing section (53-percent wing span) using thin pressure belts over the slat, main-wing, and flap elements. Flow characteristics observed in the chordwise pressure distributions included leading-edge regions of high subsonic flows, leading-edge attachment-line locations, slat and main-wing cove-flow separation and reattachment, and trailing-edge flap separation. In addition to the pressure distributions, limited skin-friction measurements were made using Preston-tube probes. Preston-tube measurements on the slat upper surface suggested relaminarization of the turbulent flow introduced by the pressure belt on the slat leading-edge surface when the slat attachment line was laminar. Computational analysis of the in-flight pressure measurements using two-dimensional, viscous multielement methods modified with simple-sweep theory showed reasonable agreement. However, overprediction of the pressures on the flap elements suggests a need for better detailed measurements and improved modeling of confluent boundary layers as well as inclusion of three-dimensional viscous effects in the analysis.

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

1993-01-01

236

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

NASA Astrophysics Data System (ADS)

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

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

2013-10-01

237

Quantum feedback by discrete quantum nondemolition measurements: Towards on-demand generation of photon-number states  

NASA Astrophysics Data System (ADS)

We propose a quantum feedback scheme for the preparation and protection of photon-number states of light trapped in a high- Q microwave cavity. A quantum nondemolition measurement of the cavity field provides information on the photon-number distribution. The feedback loop is closed by injecting into the cavity a coherent pulse adjusted to increase the probability of the target photon number. The efficiency and reliability of the closed-loop state stabilization is assessed by quantum Monte Carlo simulations. We show that, in realistic experimental conditions, the Fock states are efficiently produced and protected against decoherence.

Dotsenko, I.; Mirrahimi, M.; Brune, M.; Haroche, S.; Raimond, J.-M.; Rouchon, P.

2009-07-01

238

Using phiX174 DNA as an exogenous reference for measuring mitochondrial DNA copy number.  

PubMed

Quantitative real-time PCR has become a popular method to analyze and quantify changes in the copy number of mitochondrial DNA (mtDNA), and nuclear DNA (nDNA) is often used as an endogenous reference for mtDNA abundance. In our experience, using nDNA as a reference is problematic, due to differences in the extraction efficiency of nDNA and mtDNA and variation in the ploidy of experimental samples. Here, we report that the ratio of mtDNA to nDNA varies in repeated DNA extractions but that PhiX174 DNA, added before DNA extraction, is extracted with a similar efficiency to mtDNA, making it a suitable alternative reference for quantifying mtDNA copy number. PMID:19852770

Myers, Meagan B; Mittelstaedt, Roberta A; Heflich, Robert H

2009-10-01

239

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

National Technical Information Service (NTIS)

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 win...

W. B. Igoe

1991-01-01

240

Contralateral Delay Activity Provides a Neural Measure of the Number of Representations in Visual Working Memory  

PubMed Central

Visual working memory (VWM) helps to temporarily represent information from the visual environment and is severely limited in capacity. Recent work has linked various forms of neural activity to the ongoing representations in VWM. One piece of evidence comes from human event-related potential studies, which find a sustained contralateral negativity during the retention period of VWM tasks. This contralateral delay activity (CDA) has previously been shown to increase in amplitude as the number of memory items increases, up to the individual's working memory capacity limit. However, significant alternative hypotheses remain regarding the true nature of this activity. Here we test whether the CDA is modulated by the perceptual requirements of the memory items as well as whether it is determined by the number of locations that are being attended within the display. Our results provide evidence against these two alternative accounts and instead strongly support the interpretation that this activity reflects the current number of objects that are being represented in VWM.

Ikkai, Akiko; McCollough, Andrew W.

2010-01-01

241

Techniques for fisheye lens calibration using a minimal number of measurements  

NASA Astrophysics Data System (ADS)

A method is discussed describing how different types of Omni-Directional fisheye lenses can be calibrated for use in robotic vision. The technique discussed will allow for full calibration and correction of x,y pixel coordinates while only taking two uncalibrated and one calibrated measurement. These are done by finding the observed x,y coordinates of a calibration target. Any Fisheye lense that has a roughly spherical shape can have its distortion corrected with this technique. Two measurements are taken to discover the edges and centroid of the lens. These can be done automatically by the computer and does not require any knowledge about the lens or the location of the calibration target. A third measurement is then taken to discover the degree of spherical distortion. This is done by comparing the expected measurement to the measurement obtained and then plotting a curve that describes the degree of distortion. Once the degree of distortion is known and a simple curve has been fitted to the distortion shape, the equation of that distortion and the simple dimensions of the lens are plugged into an equation that remains the same for all types of lenses. The technique has the advantage of needing only one calibrated measurement to discover the type of lens being used.

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

2000-10-01

242

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

243

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

NASA Astrophysics Data System (ADS)

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

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

2000-02-01

244

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

SciTech Connect

The mechanisms governing solute transport through layered soil are not fully understood. Solute transport at, above, and beyond the interface between two soil layers during quasi-steady-state soil water movement was investigated using time domain reflectometry (TDR). A 0.26-m sandy loam layer was packed on top of a 1.35-m fine sand layer in a soil column. Soil water content ({theta}) and bulk soil electrical conductivity (EC{sub b}) were measured by 50 horizontal and 2 vertical TDR probes. A new TDR calibration method that gives a detailed relationship between apparent relative dielectric permittivity (K{sub s}) and {theta} was applied. Two replicate solute transport experiments were conducted adding a conservative tracer (CCl) to the surface as a short pulse. The convective lognormal transfer function model (CLT) was fitted to the TDR-measured time integral-normalized resident concentration breakthrough curves (BTCs). The BTCs and the average solute-transport velocities showed preferential flow occurred across the layer boundary. A nonlinear decrease in TDR-measured {theta} in the upper soil toward the soil layer boundary suggests the existence of a 0.10-m zone where water is confined towards fingered flow, creating lateral variations in the area-averaged water flux above the layer boundary. A comparison of the time integral-normalized flux concentration measured by vertical and horizontal TDR probes at the layer boundary also indicates a nonuniform solute transport. The solute dispersivity remained constant in the upper soil layer, but increased nonlinearly (and further down, linearly) with depth in the lower layer, implying convective-dispersive solute transport in the upper soil, a transition zone just below the boundary, and stochastic-convective solute transport in the remaining part of the lower soil.

Nissen, H.H.; Moldrup, P.; Kachanoski, R.G.

2000-02-01

245

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

USGS Publications Warehouse

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

Mueller, D. S.

2002-01-01

246

Measurements of the production and transport of helium ash on the TFTR Tokamak  

SciTech Connect

Helium ash production and transport have been measured in TFTR deuterium-tritium plasmas using charge-exchange recombination spectroscopy. The helium ash confinement time, including recycling effects, is 6--10 times the energy confinement time and is compatible with sustained ignition in a reactor. The ash confinement time is dominated by edge pumping rates rather than core transport. The measured evolution of the local thermal ash density agrees with modeling, indicating that alpha particle slowing-down calculations used in the modeling are reasonable.

Synakowski, E.J.; Bell, R.E.; Budny, R.V. [and others

1995-03-01

247

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

248

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

NASA Astrophysics Data System (ADS)

We investigate the spin transport and precession in graphene by using the Hanle effect in nonlocal and three-terminal measurement geometries. Identical spin lifetimes, spin diffusion lengths, and spin polarizations are observed in graphene devices for both techniques over a wide range of temperatures. The magnitude of the spin signals is well explained by spin transport models. These observations rules out any signal enhancements or additional scattering mechanisms at the interfaces for both geometries. This validates the applicability of both the measurement methods for graphene based spintronics devices and their reliable extractions of spin parameters.

Dankert, André; Kamalakar, Mutta Venkata; Bergsten, Johan; Dash, Saroj P.

2014-05-01

249

Laser patterning: A new approach to measure local magneto-transport properties in multifilamentary superconducting tapes  

NASA Astrophysics Data System (ADS)

The determination of inter- and intra-filament characteristics in superconducting composites such as BSCCO-Ag tapes is of great importance for material evaluation towards applications. Most attempts to separate the two contributions have relied on indirect methods based on magnetic measurements such as SQUID or magneto-optic imaging techniques. Here we show that laser patterning of superconducting BSCCO-Ag tapes constitutes a simple approach to measure local transport properties in a direct way, even able to separate inter- and intra-filament contributions to the overall transport behavior of the sample.

Sánchez Valdés, C. F.; Pérez-Penichet, C.; Noda, C.; Arronte, M.; Batista-Leyva, A. J.; Haugen, Ø.; Johansen, T. H.; Han, Z.; Altshuler, E.

2007-09-01

250

Characterization of PV array output using a small number of measured parameters  

NASA Astrophysics Data System (ADS)

A method for fitting measured I-V curves of solar modules and arrays is described. The method uses three basic parameters including open circuit voltage (Voc), short circuit current (Isc), and maximum power (Pm). By determining the influence of these parameters in variable conditions, an approximation is found for varying temperature and solar radiation which requires fewer measurements than previous models. When the parameters were tested for a single solar cell and for various types of panels, strings, and arrays, the difference between the approximated and real curves was less than three percent.

Singer, S.; Rozenshtein, B.; Surazi, S.

251

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

252

Measurement of absolute copy number variation reveals association with essential hypertension  

PubMed Central

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

2014-01-01

253

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

ERIC Educational Resources Information Center

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

BALDWIN, THOMAS S.

254

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

ERIC Educational Resources Information Center

THE 11 INSTITUTIONS AGREEING TO PARTICIPATE IN THE STUDY TO DISCOVER MORE ADEQUATE WAYS OF MEASURING IMPORTANT TACTILE-KINESTHETIC MODALITIES WERE VISITED, AND THE OPERATING PROCEDURES AND INFORMATION ON WHAT WOULD BE EXPECTED OF EACH INSTITUTION WERE OUTLINED. APPROXIMATELY 20 INSTRUCTORS BEGAN WORK ON A DETAILED CURRICULUM ANALYSIS IN THEIR…

North Carolina State Univ., Raleigh.

255

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

ERIC Educational Resources Information Center

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

WEISS, DAVID J.; AND OTHERS

256

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

257

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

NASA Technical Reports Server (NTRS)

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

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

1991-01-01

258

Plasma electron number density and electron-neutral collision frequency from complex impedance measurements  

Microsoft Academic Search

The plasma within an RF driven inductive coil interacts with the electrical generation circuit providing feedback useful for control of bulk plasma parameters. An investigation, employing a tunable RF circuit, was made applying complex impedance measurements as a plasma diagnostic. Plasma-circuit effects are modeled as capacitive coupling to the driving inductor; the magnitude of the plasma model capacitance being proportional

T. W. Hermanson

1982-01-01

259

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

260

Development of a New Method of Measuring the Characteristic Impedance and Complex Wave Number of a Porous Acoustic Material.  

National Technical Information Service (NTIS)

The specific DC flow resistance, characteristic impedance and complex wave number of air-filled fiberglass have been extracted from measurements of the peak and half-power frequencies of the two lowest-frequency normal modes of a rectangular plexiglass ca...

F. F. Schulz

1987-01-01

261

Cross-wire measurements in the wake of an airfoil at low Reynolds numbers with and without acoustic excitation  

Microsoft Academic Search

The wake structure and vortex shedding characteristics of a NACA 0025 airfoil were studied experimentally. Wind tunnel experiments were carried out for three Reynolds numbers and three angles of attack by means of cross-wire measurements, spectral analysis and complementary surface flow visualization. Evidence of wake vortex shedding and flow separation was obtained for most of the cases examined, and dependence

Serhiy Yarusevych; Pierre E Sullivan; John G Kawall

2002-01-01

262

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

263

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

264

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

Microsoft Academic Search

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

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

1995-01-01

265

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

Microsoft Academic Search

A set of experiments was conducted in the U.S. Navy's Large Cavitation Channel (LCC) into the characteristics of a liquid turbulent boundary layer at nearly zero-pressure-gradient. The hydraulically smooth, k^+ < 0.2, flat-plate test model measured 12.9 m in length and 3.05 m in span and was approximately centered in the LCC test section. Data was gathered at flow speeds

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

2006-01-01

266

Determination of kinetic parameters of enzyme-catalyzed reactions with a minimum number of velocity measurements.  

PubMed

Duggleby [Duggleby, R.G., 1979. Experimental designs for estimating kinetic parameters for enzyme-catalyzed reactions. J. Theor. Biol. 81, 672-684] discussed the "design of several replicate measurements of the velocity at as many experimental conditions as there are parameters to be estimated." He discussed the application of this method to A-->products, without and with competitive inhibition, and commented briefly on A+B-->products. The availability of computer applications that can solve large sets of simultaneous equations makes it possible to use this method to calculate kinetic parameters for more complicated enzyme mechanisms. This article is concerned with rapid-equilibrium rate equations, but this method can also be used with steady-state rate equations. Computer programs are provided for the calculation of the three kinetic parameters for ordered A+B-->products from three velocity measurements and for the calculation of the four kinetic parameters for random A+B-->products from four velocity measurements. Computer programs are also provided for competitive inhibition, uncompetitive inhibition, and mixed inhibition of ordered A+B-->products. PMID:18582902

Alberty, Robert A

2008-09-01

267

Laboratory measurements of the transport of radon gas through concrete samples  

SciTech Connect

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

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

1995-06-01

268

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

PubMed Central

Two studies investigated the reliability and predictive validity of commonly used measures and models of Approximate Number System acuity (ANS). Study 1 investigated reliability by both an empirical approach and a simulation of maximum obtainable reliability under ideal conditions. Results showed that common measures of the Weber fraction (w) are reliable only when using a substantial number of trials, even under ideal conditions. Study 2 compared different purported measures of ANS acuity as for convergent and predictive validity in a within-subjects design and evaluated an adaptive test using the ZEST algorithm. Results showed that the adaptive measure can reduce the number of trials needed to reach acceptable reliability. Only direct tests with non-symbolic numerosity discriminations of stimuli presented simultaneously were related to arithmetic fluency. This correlation remained when controlling for general cognitive ability and perceptual speed. Further, the purported indirect measure of ANS acuity in terms of the Numeric Distance Effect (NDE) was not reliable and showed no sign of predictive validity. The non-symbolic NDE for reaction time was significantly related to direct w estimates in a direction contrary to the expected. Easier stimuli were found to be more reliable, but only harder (7:8 ratio) stimuli contributed to predictive validity.

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

2013-01-01

269

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

270

Large-scale laboratory measurements of sheet flow sediment transport in the swash zone  

NASA Astrophysics Data System (ADS)

Existing sediment transport models show poor predictive quality when applied to the swash zone, indicating that the underlying processes of swash zone sediment transport are not yet fully understood. The recognition that more detailed measurements are needed to improve understanding of swash-zone processes has led to several recent innovations in swash-zone measurement techniques. One of these innovative measurement techniques, the Conductivity Concentration Profiler (CCP), was developed to address the issue of near-bed (sheet flow) sediment transport, which is believed to be an important part of the overall swash-zone sediment transport. Measurements of sheet flow processes in the swash zone from the Barrier Dynamics Experiment (Bardex-II) are presented. The aim of this study was to investigate the dynamics of a coastal barrier system and develop an increased understanding of cross-shore sediment transport processes in the nearshore zone of sandy beaches. A 70-m long, near-prototype scale sandy barrier was constructed in a large wave flume facility and equipped with over 200 sensors to measure hydrodynamics and sediment processes ranging from the shoaling-wave zone to the back barrier. CCP sensors were deployed at three locations in the swash zone as part of the ';swash and berm dynamics' work package. Onshore-directed pressure gradients, observed during the initial stages of uprush, enhanced sediment mobilization. The combination of near-bed sediment mobilization due to pressure gradients (known as plug flow) and shear stress (sheet flow) is examined. Sediment load in the sheet flow layer is also compared to suspended load and total load measured using an array of optical backscatter sensors. The sheet flow layer thickness is compared to hydrodynamic forcing such as bed shear stress and the effect of groundwater exchange.

Lanckriet, T. M.; Puleo, J. A.; Foster, D. L.

2013-12-01

271

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

272

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...

273

Solute transport and water content measurements in clay soils using time domain reflectometry  

Microsoft Academic Search

Clayey and saline soils have been shown to be problematic for time domain reflectometry (TDR) measurements. This study presents some of these problems and discusses solutions to them. Thirteen solute transport experiments were carried out in three undisturbed soil columns of swelling clay soil from Tunisia, labelled SI, S2, and S3 respectively. The columns were collected at three different physiographical

MAGNUS PERSSON; RONNY BERNDTSSON; SLAH NASRI; JEAN ALBERGEL; PATRICK ZANTE; YUKI YUMEGAKI

2001-01-01

274

Solute transport and water content measurements in clay soils using time domain reflectometry  

Microsoft Academic Search

Clayey and saline soils have been shown to be problematic for time domain reflectometry (TDR) measurements. This study presents some of these problems and discusses solutions to them. Thirteen solute transport experiments were carried out in three undisturbed soil columns of swelling clay soil from Tunisia, labelled S1, S2, and S3 respectively. The columns were collected at three different physiographical

MAGNUS PERSSON; RONNY BERNDTSSON; SLAH NASRI; JEAN ALBERGEL; PATRICK ZANTE; YUKI YUMEGAKI

2000-01-01

275

Guidebook for Rural Demand-Response Transportation: Measuring, Assessing, and Improving Performance.  

National Technical Information Service (NTIS)

This guidebook will be of interest to rural public transportation systems that provide demand-response transit (DRT) services and to the communities they serve. It is a resource to assist DRT systems to measure, assess, and improve their performance, focu...

B. McCollom E. Ellis

2009-01-01

276

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

National Technical Information Service (NTIS)

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

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

1984-01-01

277

Measuring transport efficiency with adjustment of accidents: case of Taipei bus transit  

Microsoft Academic Search

While producing the desirable outputs (transport services), a bus transit occasionally also produces accidents, which may lead to fatalities, serious injuries, slight injuries and\\/or property losses. As such, without explicitly taking into account the negative effects of accidents on the outputs when measuring efficiency for bus transit, the interpretation of results could be misleading. To be more rational, this article

Erwin T. J. Lin; Lawrence W. Lan; Agnes K. Y. Chiu

2010-01-01

278

Aerosol measurements from a recent Alaskan volcanic eruption: Implications for volcanic ash transport predictions  

Microsoft Academic Search

Size and time-resolved aerosol compositional measurements conducted during the 2006 eruption of Augustine Volcano provide quantitative information on the size and concentration of the fine volcanic ash emitted during the eruption and carried and deposited downwind. These data can be used as a starting point to attempt to validate volcanic ash transport models. For the 2006 eruption of Augustine Volcano,

Catherine F. Cahill; Peter G. Rinkleff; Jonathan Dehn; Peter W. Webley; Thomas A. Cahill; David E. Barnes

2010-01-01

279

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

Microsoft Academic Search

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

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

2006-01-01

280

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

281

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

NASA Astrophysics Data System (ADS)

A useful plasma diagnostic is the measurement of electron number density. One way to accomplish such measurements is to determine the contribution to the broadening of a spectral line due to the Stark effect. To simplify and extend such electron density measurements across computer platforms, a program that calculates electron number density from the Stark-broadened hydrogen-beta line has been written for the LabVIEW ® environment. This program calculates electron number densities from the field strength that would be exerted on a hydrogen atom immersed in a plasma. Using the new program, the electron number density in a glow discharge is calculated for two different operating conditions. Not surprisingly, the results indicate that to increase the current density in the discharge, the source electrodes must be reduced in surface area. This article is an electronic publication in Spectrochimica Acta Electronica (SAE), the electronic section of Spectrochimica Acta Part B (SAB). The hardcopy text is accompanied by one disk with an executable program (written for Apple Macintosh), data and text files including a manual.

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

1995-08-01

282

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

283

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

NASA Astrophysics Data System (ADS)

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

Beauchesne, Hugues; Grégoire, Thomas

2014-05-01

284

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

SciTech Connect

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

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

1985-01-18

285

Spectroscopic measurements and impurity transport studies on MST Reversed Field Pinch  

NASA Astrophysics Data System (ADS)

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

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

2012-10-01

286

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

287

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

288

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

289

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

290

Ionic diffusion in quartz studied by transport measurements, SIMS and atomistic simulations  

NASA Astrophysics Data System (ADS)

Ionic diffusion in the quartz-?-eucryptite system is studied by DC transport measurements, SIMS and atomistic simulations. Transport data show a large transient increase in ionic current at the ?-? phase transition of quartz (the Hedvall effect). The SIMS data indicate two diffusion processes, one involving rapid Li+ motion and the other involving penetration of Al and Li atoms into quartz at the phase transition. Atomistic simulations explain why the fine microstructure of twin domain walls in quartz near the transition does not hinder Li+ diffusion.

Sartbaeva, Asel; Wells, Stephen A.; Redfern, Simon A. T.; Hinton, Richard W.; Reed, Stephen J. B.

2005-02-01

291

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

292

Measurements of surface-pressure fluctuations on the XB-70 airplane at local Mach numbers up to 2.45  

NASA Technical Reports Server (NTRS)

Measurements of surface-pressure fluctuations were made at two locations on the XB-70 airplane for nine flight-test conditions encompassing a local Mach number range from 0.35 to 2.45. These measurements are presented in the form of estimated power spectral densities, coherence functions, and narrow-band-convection velocities. The estimated power spectral densities compared favorably with wind-tunnel data obtained by other experimenters. The coherence function and convection velocity data supported conclusions by other experimenters that low-frequency surface-pressure fluctuations consist of small-scale turbulence components with low convection velocity.

Lewis, T. L.; Dods, J. B., Jr.; Hanly, R. D.

1973-01-01

293

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

SciTech Connect

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

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

1992-01-01

294

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

SciTech Connect

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

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

1992-10-01

295

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

Microsoft Academic Search

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

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

1998-01-01

296

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

Microsoft Academic Search

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

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

2006-01-01

297

Direct measurements of the transport of nonequilibrium electrons in gold films with different crystal structures  

SciTech Connect

The transport of femtosecond-laser-excited nonequilibrium electrons across polycrystalline and single-crystalline gold films has been investigated through time-of-flight measurements. The thicknesses of the films range from 25 to 400 nm. Ballistic electrons as well as electrons interacting with other electrons and/or with the lattice have been observed. The ballistic component dominates the transport in the thinner films, whereas the interactive transport mechanism is dominant at the upper end of the thickness range. A slower effective velocity of the interactive component is observed in the polycrystalline samples, and is assumed to arise from the presence of grain boundaries. The reflection coefficient of excited electrons at the grain boundaries is extracted from the experiment and is estimated to be [ital r][congruent]0.12. The experiment also suggests that thermal equilibrium among the excited electrons is not fully established in the first [similar to]500 fs after excitation.

Juhasz, T. (Department of Physics, University of California, Irvine, California 92717 (United States)); Elsayed-Ali, H.E. (Department of Electrical and Computer Engineering, Old Dominion University, Norfolk, Virginia 23529 (United States)); Smith, G.O.; Suarez, C.; Bron, W.E. (Department of Physics, University of California, Irvine, California 92717 (United States))

1993-11-15

298

Number Line  

NSDL National Science Digital Library

In this brief article the numerous uses of the number line are detailed: counting, measurement, addition, subtraction, decimals, and fractions. The article contains visual representations of the some of the concepts and links to related topics.

2012-08-27

299

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

Microsoft Academic Search

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

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

1999-01-01

300

Measuring cation transport by Na,K- and H,K-ATPase in Xenopus oocytes by atomic absorption spectrophotometry: an alternative to radioisotope assays.  

PubMed

Whereas cation transport by the electrogenic membrane transporter Na(+),K(+)-ATPase can be measured by electrophysiology, the electroneutrally operating gastric H(+),K(+)-ATPase is more difficult to investigate. Many transport assays utilize radioisotopes to achieve a sufficient signal-to-noise ratio, however, the necessary security measures impose severe restrictions regarding human exposure or assay design. Furthermore, ion transport across cell membranes is critically influenced by the membrane potential, which is not straightforwardly controlled in cell culture or in proteoliposome preparations. Here, we make use of the outstanding sensitivity of atomic absorption spectrophotometry (AAS) towards trace amounts of chemical elements to measure Rb(+) or Li(+) transport by Na(+),K(+)- or gastric H(+),K(+)-ATPase in single cells. Using Xenopus oocytes as expression system, we determine the amount of Rb(+) (Li(+)) transported into the cells by measuring samples of single-oocyte homogenates in an AAS device equipped with a transversely heated graphite atomizer (THGA) furnace, which is loaded from an autosampler. Since the background of unspecific Rb(+) uptake into control oocytes or during application of ATPase-specific inhibitors is very small, it is possible to implement complex kinetic assay schemes involving a large number of experimental conditions simultaneously, or to compare the transport capacity and kinetics of site-specifically mutated transporters with high precision. Furthermore, since cation uptake is determined on single cells, the flux experiments can be carried out in combination with two-electrode voltage-clamping (TEVC) to achieve accurate control of the membrane potential and current. This allowed e.g. to quantitatively determine the 3Na(+)/2K(+) transport stoichiometry of the Na(+),K(+)-ATPase and enabled for the first time to investigate the voltage dependence of cation transport by the electroneutrally operating gastric H(+),K(+)-ATPase. In principle, the assay is not limited to K(+)-transporting membrane proteins, but it may work equally well to address the activity of heavy or transition metal transporters, or uptake of chemical elements by endocytotic processes. PMID:23462593

Dürr, Katharina L; Tavraz, Neslihan N; Spiller, Susan; Friedrich, Thomas

2013-01-01

301

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

302

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

PubMed

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

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

2013-01-01

303

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

PubMed Central

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

Szucs, Denes; Nobes, Alison; Devine, Amy; Gabriel, Florence C.; Gebuis, Titia

2013-01-01

304

Validation of a fluorescence-based high-throughput assay for the measurement of neurotransmitter transporter uptake activity.  

PubMed

Pre-synaptic dopamine, norepinephrine and serotonin transporters (DAT, NET and SERT) terminate synaptic catecholamine transmission through reuptake of released neurotransmitter. Common approaches for studying these transporters involve radiolabeled substrates or inhibitors which, however, have several limitations. In this study we have used a novel neurotransmitter transporter uptake assay kit. The assay employs a fluorescent substrate that mimics the biogenic amine neurotransmitters and is taken up by the cell through the specific transporters, resulting in increased fluorescence intensity. In order to validate the assay, a variety of reference and proprietary neurotransmitter transporter ligands from a number of chemical and pharmacological classes were tested. The ability of these compounds to inhibit the selective transporter-mediated uptake demonstrated a similar rank order of potency and IC(50) values close to those obtained in radiolabeled neurotransmitter uptake assays. The described assay enables monitoring of dynamic transport activity of DAT, NET and SERT and is amenable for high-throughput screening and compound characterization. PMID:18222006

Jørgensen, Susanne; Nielsen, Elsebet Østergaard; Peters, Dan; Dyhring, Tino

2008-03-30

305

[Measurement of the transport activities of bile salt export pump using chemiluminescence detection method].  

PubMed

Monovalent bile acids, such as taurine- and glycine-conjugated bile acids, are excreted into bile by bile salt export pumps (BSEP, ABCB11). Human BSEP (hBSEP) is physiologically important because it was identified as the gene responsible for the genetic disease: progressive familial intrahepatic cholestasis type 2 (PFIC-2). The evaluation of the inhibitory effect of hBSEP transport activity provides significant information for predicting toxic potential in the early phase of drug development. The role and function of hBSEP have been investigated by the examination of the ATP-dependent transport of radioactive isotopically (RI)-labeled bile acid such as a tritium labeled taurocholic acid, in membrane vesicles obtained from hBSEP-expressing cells. The chemiluminescence detection method using 3alpha-hydroxysteroid dehydrogenase (3alpha-HSD) had been developed for a simple analysis of bile acids in human biological fluids. This method is extremely sensitive and it may be applicable for the measurements of bile acid transport activities by hBSEP vesicles without using RI-labeled bile acid. The present paper deals with an application of the chemiluminescence detection method using 3alpha-HSD with enzyme cycling method to the measurement of ATP-dependent transport activities of taurocholic acid (T-CA) in membrane vesicles obtained from hBSEP-expressing Sf9 cells. Calibration curves for T-CA was linear over the range from 10 to 400 pmol/ml. The values of the kinetic parameters for hBSEP vesicles obtained by the chemiluminescence detection method were comparable with the values of that obtained by liquid chromatography-mass spectrometry method. This assay method was highly useful for the measurements of bile acid transport activities. PMID:20460875

Yamaguchi, Kana; Murai, Tsuyoshi; Yabuuchi, Hikaru; Hui, Shu-Ping; Kurosawa, Takao

2010-05-01

306

Spectroscopic and transport measurements of single molecules in solution using an electrokinetic trap  

NASA Astrophysics Data System (ADS)

In aqueous solution, diffusion generally limits the observation window of a nano-meter sized single molecule to milliseconds and prevents quantitative determination of spectroscopic and transport properties molecule-by-molecule. The anti-Brownian electrokinetic (ABEL) trap is a feedback-based microfluidic device that enables prolonged (multiseconds) observation of single molecules in solution. The amount of information that can be extracted from each molecule in solution is thus boosted by three orders of magnitude. We describe recent advances in extending the ABEL trap to conduct both spectroscopic and transport measurements of single trapped molecules. First, by combining the trap with multi-parameter fluorescence detection, synchronized dynamics in different observables can be visualized in solution. We use single molecules of Atto 633 as an example and show that this popular label switches between different emissive states under common imaging conditions. Next, we show how transport properties of trapped single molecules can be extracted in addition to spectroscopic readouts. Due to their direct sensitivity to molecular size and charge, measured transport coefficients can be used to distinguish different molecular species and trace biomolecular interactions in solution. We demonstrate this new paradigm by monitoring DNA hybridization/melting in real-time.

Wang, Quan; Moerner, W. E.

2014-03-01

307

Three-dimensional variations of atmospheric CO2: aircraft measurements and multi-transport model simulations  

NASA Astrophysics Data System (ADS)

Numerical simulation and validation of three-dimensional structure of atmospheric carbon dioxide (CO2) is necessary for quantification of transport model uncertainty and its role on surface flux estimation by inverse modeling. Simulations of atmospheric CO2 were performed using four transport models and two sets of surface fluxes compared with an aircraft measurement dataset of Comprehensive Observation Network for Trace gases by AIrLiner (CONTRAIL), covering various latitudes, longitudes, and heights. Under this transport model intercomparison project, spatiotemporal variations of CO2 concentration for 2006-2007 were analyzed with a three-dimensional perspective. Results show that the models reasonably simulated vertical profiles and seasonal variations not only over northern latitude areas but also over the tropics and southern latitudes. From CONTRAIL measurements and model simulations, intrusion of northern CO2 in to the Southern Hemisphere, through the upper troposphere, was confirmed. Furthermore, models well simulated the vertical propagation of seasonal variation in the northern free troposphere. However, significant model-observation discrepancies were found in Asian regions, which are attributable to uncertainty of the surface CO2 flux data. In summer season, differences in latitudinal gradients by the fluxes are comparable to or greater than model-model differences even in the free troposphere. This result suggests that active summer vertical transport sufficiently ventilates flux signals up to the free troposphere and the models could use those for inferring surface CO2 fluxes.

Niwa, Y.; Patra, P. K.; Sawa, Y.; Machida, T.; Matsueda, H.; Belikov, D.; Maki, T.; Ikegami, M.; Imasu, R.; Maksyutov, S.; Oda, T.; Satoh, M.; Takigawa, M.

2011-12-01

308

A Flow-compartmental Model To Measure Glucose Transport And Insulin Control Upon It In The Human Skeletal Muscle  

Microsoft Academic Search

Glucos transport into (k. , min ) and out (kou , mine’) of the cell in #e human skeletal muscfe is a critical step of glucose metabolism. Its measurement in humans is however difficult both in terms of experimental design and kinetic data analysis. Here we present a linear model for measuring glucose transport in the human forearm skeletal muscle

Maria Pia Saccomani; Claudio Cobelli

1990-01-01

309

A Need-Based Measure of Consumer Well Being (CWB) in Relation to Personal Transportation: Nomological Validation  

ERIC Educational Resources Information Center

This paper reports the results of three studies designed to test the nomological validity of a consumer well-being (CWB) measure in relation to personal transportation. The CWB measure was developed guided by the theoretical notion that the CWB in relation to personal transportation vehicles is significantly enhanced when the consumption of the…

Sirgy, M. Joseph; Lee, Dong-Jin; Kressmann, Frank

2006-01-01

310

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

311

Noninvasive Quantitative Measurement of Colloid Transport in Mesoscale Porous Media Using Time Lapse Fluorescence Imaging  

Microsoft Academic Search

We demonstrate noninvasive quantitative imaging of colloid and solute transport at millimeter to decimeter (meso-) scale. Ultraviolet (UV) excited fluorescent solute and colloid tracers were independently measured simultaneously during co-advection through saturated quartz sand. Pulse-input experiments were conducted at constant flow rates and ionic strengths 10-3 ,1 0 -2 and 10-1 M NaCl. Tracers were 1.9 Ìm carboxylate latex microspheres

JONATHAN W. B RIDGE; STEVEN A. B ANWART

312

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

Microsoft Academic Search

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

F. Wissing; J. A. C. Smith

2000-01-01

313

Wave-Modified Ion Distributions and Cross-Field Transport Measurements by Laser-Induced Fluorescence  

Microsoft Academic Search

We present results of studies of cross-field transport and ion heating produced by electrostatic ion-cyclotron waves (EICW). Both coherent and turbulent wave spectra were generated, and the modification of ion velocities and phase-space trajectories by fluctuations of each type were measured using two optical diagnostic techniques recently developed at U. C. Irvine. The optical diagnostics employed in these experiments are

David Newton Hill

1983-01-01

314

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

Microsoft Academic Search

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

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

2006-01-01

315

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

Microsoft Academic Search

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

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

2005-01-01

316

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

Microsoft Academic Search

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

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

2001-01-01

317

Transportation  

NSDL National Science Digital Library

A unit designed to increase students' knowledge and understanding of diesel and gasoline engines, providing an introduction for students interested in more specialized training in the automobile field and its scientific principles through math, science, and chemistry. It will also help students realize the importance of transportation, and will help them meet their needs in math through problem solving by dealing with materials in their world, letting them develop skills and techniques through hands-on experience. Includes more than 20 problems to solve.

Bryant, Joyce

2007-05-12

318

Hall-Effect Measurements Under AC Excitation for the Reconstruction of Obliterated Serial Numbers in Magnetic Steels  

NASA Astrophysics Data System (ADS)

Existing forensic techniques employed to recover obliterated serial numbers fall mainly into one of two categories, those requiring extensive sample preparation including the use of acid etchants, and those utilizing magnetic particles to image irregularities in surface magnetic properties. The former is time consuming and utilizes potentially harmful chemicals while the latter messy and potentially low in sensitivity. A new approach is being investigated whereby the stray magnetic field is measured using a Hall effect sensor. The sample is magnetized using an electromagnetic c-core yoke. For increased sensitivity, an AC approach is being utilized that benefits from the use of a lock-in amplifier. The approach has been tested on some artificial specimens and part of a real gun with the serial numbers removed by surface grinding.

Johnson, M. J.; Lo, C. C. H.; Naidu, L. B.

2004-02-01

319

Heat transfer measurements on an incidence-tolerant low pressure turbine blade in a high speed linear cascade at low to moderate Reynolds numbers  

NASA Astrophysics Data System (ADS)

Runway-independent aircraft are expected to be the future for short-haul flights by improving air transportation and reducing area congestion encountered in airports. The Vehicle Systems Program of NASA identified a Large Civil Tilt-Rotor, equipped with variable-speed power-turbine engines, as the best concept. At cruise altitude, the engine rotor-speed will be reduced by as much as the 50% of take-off speed. The large incidence variation in the low pressure turbine associated with the change in speed can be detrimental to the engine performance. Low pressure turbine blades in cruise altitude are more predisposed to develop regions of boundary layer separation. Typical phenomenon such as impinging wakes on downstream blades and mainstream turbulences enhance the complexity of the flow in low pressure turbines. It is therefore important to be able to understand the flow behavior to accurately predict the losses. Research facilities are seldom able to experimentally reproduce low Reynolds numbers at relevant engine Mach number. Having large incidence swing as an additional parameter in the investigation of the boundary layer development, on a low pressure turbine blade, makes this topic unique and as a consequence requires a unique facility to conduct the experimental research. The compressible flow wind tunnel facility at the University of North Dakota had been updated to perform steady state experiments on a modular-cascade, designed to replicate a large variation of the incidence angles. The high speed and low Reynolds number facility maintained a sealed and closed loop configuration for each incidence angle. The updated facility is capable to produce experimental Reynolds numbers as low as 45,000 and as high as 570,000 at an exit Mach number of 0.72. Pressure and surface temperature measurements were performed at these low pressure turbine conditions. The present thesis investigates the boundary layer development on the surface of an Incidence-tolerant blade. The heat transfer approach is the method used to obtain knowledge of the state of the boundary layer on the surface of the blade. Pressure and temperature distributions are acquired for Reynolds numbers of 50,000, 66,000, 228,000, and 568,000 at an exit Mach number of 0.72, and Reynolds numbers of 228,000, and 568,000 at an exit Mach number of 0.35. These experimental flow conditions are conducted at different flow inlet angles of 40°, 34.2°, 28°, 18°, 8°, -2.6°, -12°, and -17°, and at two free-stream turbulence levels. Results of the analyses performed show that as the incidence angle decreases, a region of laminar separation bubble forms on the pressure surface and grows toward the trailing-edge. It is also noted that the position of the leading-edge moves as the incidence angle varies. A transitional flow is observed on both the pressure and suction surfaces, mainly at the two highest incidence angles, for the high turbulence case. This investigation also reveals that the Stanton number increases as the mainstream turbulence increases, and that the Stanton number at the leading-edge increases as the Reynolds number decreases, as it is documented in the literature.

Moualeu, Leolein Patrick Gouemeni

320

Contactless measurement of hysteretic transport AC losses in multifilamentary BiSrCaCuO-2223/Ag tapes  

NASA Astrophysics Data System (ADS)

We demonstrate how the hysteretic transport AC losses in multifilamentary superconducting tapes can be determined in contactless way using a pick-up coil attached to the tape wide face. To transform the pick-up coil signal into the true loss signal, certain assumptions about the distribution of current in the tape section must be adopted. We show that the simple assumption of uniformly distributed current density gives results that are correct within 25%. A more complex model based on distribution of remanent currents brought the agreement between contactless and direct measurement to within 10%. Since the coil signal is directly proportional to the number of turns, the method provides increased sensitivity compared to that with voltage contacts. This can be helpful when investigating tapes with extremely low AC losses. Finally, we discuss how the comparison of direct and contactless methods can give information about filament nonuniformity.

Gömöry, F.; Bettinelli, D.; Gherardi, L.; Crotti, G.; Morin, D.

1998-11-01

321

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

PubMed

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

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

2012-02-01

322

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

323

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

324

Quantitative measurement of intracellular transport of nanocarriers by spatio-temporal image correlation spectroscopy  

PubMed Central

Spatio-temporal image correlation spectroscopy (STICS) is a powerful technique for assessing the nature of particle motion in complex systems although it has been rarely used to investigate the intracellular dynamics of nanocarriers so far. Here we introduce a method to characterize the mode of motion of nanocarriers and to quantify their transport parameters on different length scales from single-cell to subcellular level. Using this strategy we were able to study the mechanisms responsible for the intracellular transport of DOTAP-DOPC/DNA and DC-Chol-DOPE/DNA lipoplexes in CHO-K1 live cells. Measurement of both diffusion coefficients and velocity vectors (magnitude and direction) averaged over regions of the cell revealed the presence of distinct modes of motion. Lipoplexes diffused slowly on the cell surface (diffusion coefficient, D ? 0.003 µm2/s). In the cytosol, the lipoplexes’ motion was characterized by active transport with average velocity ? ? 0.03 µm/s and random motion. The method permitted us to generate intracellular transport map showing several regions of concerted motion of lipoplexes.

Coppola, S; Pozzi, D; De Sanctis, S Candeloro; Digman, M A; Gratton, E; Caracciolo, G

2013-01-01

325

New Devices for Integrating Controlled Assembly, Imaging and Transport Measurements of Nanoscale Structures  

NASA Astrophysics Data System (ADS)

Experiments on charge transport in nanostructures require knowledge and control of the structural details in order to achieve an improved understanding of the transport mechanisms. Typical devices used to probe the electrical properties of nanometer scale objects do not allow for fluorescence imaging or the Angstrom resolution imaging that is available with Transmission Electron Microscopy. A substantial limitation on the knowledge of the sample's content and configuration is thus imposed. Furthermore, uncontrolled sample arrangement in these devices can introduce extraneous channels for transport. We have fabricated a new kind of device which resolves these issues. Silicon Nitride wafers are modified in a multi-step lithography process to yield a device which allows transmission based imaging of nanostructures positioned inside a submicron electrode gap. Additional lithographic steps make it possible to direct the assembly of the nanostructures. We discuss specific examples involving nanocrystals. This fabrication process allows for a range of device geometries which offer solutions to critical issues that are encountered when performing transport measurements on nanostructures. * This work is supported at Penn by the ONR Young Investigator Award # N000140410489, the American Chemical Society and the startup funds at Penn. MF acknowledges funding from the NSF IGERT Program.

Fischbein, Michael

2005-03-01

326

How to Measure Drug Transport across the Blood-Brain Barrier  

PubMed Central

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

Bickel, Ulrich

2005-01-01

327

Detection and correction of blinking bias in image correlation transport measurements of quantum dot tagged macromolecules.  

PubMed

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

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

2007-08-15

328

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

NASA Astrophysics Data System (ADS)

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

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

2010-08-01

329

Viscous flow through slowly expanding or contracting porous walls with low seepage Reynolds number: a model for transport of biological fluids through vessels.  

PubMed

In this article, the problem of laminar, isothermal, incompressible and viscous flow in a rectangular domain bounded by two moving porous walls, which enable the fluid to enter or exit during successive expansions or contractions, is investigated. The governing non-linear equations and their associated boundary conditions are transformed into a highly non-linear ordinary differential equation. The series solution of the problem is obtained by utilising the homotopy perturbation method. Graphical results are presented to investigate the influence of the non-dimensional wall dilation rate and seepage Reynolds number (Re) on the velocity, normal pressure distribution and wall shear stress. Since the transport of biological fluids through contracting or expanding vessels is characterised by low seepage Res, the current study focuses on the viscous flow driven by small wall contractions and expansions of two weakly permeable walls. PMID:21347910

Dinarvand, Saeed

2011-10-01

330

Copy-number variation of the neuronal glucose transporter gene SLC2A3 and age of onset in Huntington's disease.  

PubMed

Huntington's disease (HD) is a devastating neurodegenerative disorder which is inherited in an autosomal dominant manner. HD is caused by a trinucleotide CAG repeat expansion that encodes a polyglutamine stretch in the huntingtin (HTT) protein. Mutant HTT expression leads to a myriad of cellular dysfunctions culminating in neuronal loss and consequent motor, cognitive and psychiatric disturbances in HD patients. The length of the CAG repeat is inversely correlated with age of onset (AO) in HD patients, while environmental and genetic factors can further modulate this parameter. Here, we explored whether the recently described copy-number variation (CNV) of the gene SLC2A3-which encodes the neuronal glucose transporter GLUT3-could modulate AO in HD. Strikingly, we found that increased dosage of SLC2A3 delayed AO in an HD cohort of 987 individuals, and that this correlated with increased levels of GLUT3 in HD patient cells. To our knowledge this is the first time that CNV of a candidate gene has been found to modulate HD pathogenesis. Furthermore, we found that increasing dosage of Glut1-the Drosophila melanogaster homologue of this glucose transporter-ameliorated HD-relevant phenotypes in fruit flies, including neurodegeneration and life expectancy. As alterations in glucose metabolism have been implicated in HD pathogenesis, this study may have important therapeutic relevance for HD. PMID:24452335

Vittori, Angelica; Breda, Carlo; Repici, Mariaelena; Orth, Michael; Roos, Raymund A C; Outeiro, Tiago F; Giorgini, Flaviano; Hollox, Edward J

2014-06-15

331

High conversion of coal to transportation fuels for the future with low HC gas production. Progress report Number 10, January 1--March 31, 1995  

SciTech Connect

An objective of the Department of Energy in funding research in coal liquefaction, is to produce a synthetic crude from coal at a cost lower than $30.00 per barrel (Task A). A second objective is to produce a fuel which is low in aromatics, yet of sufficiently high octane number for use in the gasoline-burning transportation vehicles of today. To meet this second objective, research was proposed for conversion of the highly-aromatic liquid product from coal conversion to a product high in isoparaffins, which compounds in the gasoline range exhibit a high octane number (Task B). Experimental coal liquefaction studies conducted in a batch microreactor have demonstrated potential for high conversions of coal to liquids with low yields of hydrocarbon (HC) gases, hence small consumption of hydrogen in the primary liquefaction step. Ratios of liquids/HC gases as high as 30/1, at liquid yields as high as 82% of the coal by weight, have been achieved. The principal objective of this work is to examine how nearly one may approach these results in a continuous-flow system, at a size sufficient to evaluate the process concept for production of transportation fuels from coal. A continuous-flow reactor system is to be designed, constructed and operated. The system is to be computer-operated for process control and data logging, and is to be fully instrumented. The primary liquid products will be characterized by GC, FTIR, and GC/MS, to determine the types and quantities of the principal components produced under conditions of high liquids production with high ratios of liquids/HC gases. From these analyses, together with GC analyses of the HC gases, hydrogen consumption for the conversion to primary liquids will be calculated. Conversion of the aromatics of this liquid product to isoparaffins will be investigated. Results to date on both tasks are presented.

Wiser, W.H.; Oblad, A.G.

1995-04-01

332

Static and dynamic pressure measurements on a NACA 0012 airfoil in the Ames High Reynolds Number Facility  

NASA Technical Reports Server (NTRS)

The supercritical flows at high subsonic speeds over a NACA 0012 airfoil were studied to acquire aerodynamic data suitable for evaluating numerical-flow codes. The measurements consisted primarily of static and dynamic pressures on the airfoil and test-channel walls. Shadowgraphs were also taken of the flow field near the airfoil. The tests were performed at free-stream Mach numbers from approximately 0.7 to 0.8, at angles of attack sufficient to include the onset of buffet, and at Reynolds numbers from 1 million to 14 million. A test action was designed specifically to obtain two-dimensional airfoil data with a minimum of wall interference effects. Boundary-layer suction panels were used to minimize sidewall interference effects. Flexible upper and lower walls allow test-channel area-ruling to nullify Mach number changes induced by the mass removal, to correct for longitudinal boundary-layer growth, and to provide contouring compatible with the streamlines of the model in free air.

Mcdevitt, J. B.; Okuno, A. F.

1985-01-01

333

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

334

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

335

Fast electron temperature, MHD and transport measurements on NSTX using a multi-energy SXR array  

NASA Astrophysics Data System (ADS)

A compact multi-energy soft X-ray array has been developed for fast (<=0.1 ms) time and space-resolved electron temperature, MHD and transport measurements on the National Spherical Torus Experiment (NSTX). The electron temperature is obtained by modeling the slope of the continuum radiation from ratios of the Abel inverted radial emissivity profiles in three energy ranges [1]. The applicability of this diagnostic technique to radio frequency electron heating and current drive experiments, perturbative electron and impurity transport studies, as well as an analysis of the impact of several types of MHD activity such as NTMs, RWMs, ELMs and Fishbones will be discussed. This work supported by U.S. DoE Contract No. DE-AC02-76CH03073 DoE and grant No. DE-FG02-99ER5452 at The Johns Hopkins University. [1] L. F. Delgado-Aparicio, et al., Plasma Phys. Controlled Fusion, 49, 1245 (2007).

Delgado-Aparicio, L. F.; Stutman, D.; Tritz, K.; Finkenthal, M.; Bell, R.; Hosea, J.; Kaye, S.; Leblanc, B.; Sabbagh, S.

2007-11-01

336

Investigation of transport properties in polymer/fullerene blends using time-of-flight photocurrent measurements  

NASA Astrophysics Data System (ADS)

The electron and hole transport properties of blends of poly[2-methoxy-5-(3',7'-dimethyloctyloxy)-1-4-phenylene vinylene], (MDMO-PPV) and [6,6]-phenyl C61-butyric acid methyl ester (PCBM) are investigated at room temperature using time-of-flight photocurrent measurements as a function of blend composition and laser excitation intensity. The experimental results are consistent with the notion of a mobility edge for holes in this material that delineates long-lived trapping and mobile carrier states. Electron transport in PCBM appears to be less dispersive than that of holes in MDMO-PPV in the blend, with electron mobilities in the former exceeding hole mobilities in the latter by up to two orders of magnitude. Photocurrent generation in corresponding solar cell devices may therefore be limited by the low hole mobility of MDMO-PPV.

Choulis, S. A.; Nelson, J.; Kim, Y.; Poplavskyy, D.; Kreouzis, T.; Durrant, J. R.; Bradley, D. D. C.

2003-11-01

337

Measurement of preheating due to radiation and nonlocal electron heat transport in laser-irradiated targets  

SciTech Connect

This paper reports an experimental study on preheating of laser-irradiated targets. We performed temperature measurements at the rear surface of laser-irradiated targets under conditions of two different laser wavelengths (0.35 or 0.53 mum) and several intensities (2x10{sup 13}-1x10{sup 14} W/cm{sup 2}) in order to verify an effect of radiation and nonlocal electron heat transport. The preheating temperature was evaluated by observing self-emission, reflectivity, and expansion velocity at the rear surface of planar polyimide foils. The experimental results show that the x-ray radiation is dominant for preheating for 0.35-mum laser irradiation, but contribution of nonlocal electron heat transport is not negligible for 0.53-mum laser irradiation conditions.

Otani, K.; Shigemori, K.; Kadono, T.; Hironaka, Y.; Nakai, M.; Shiraga, H.; Azechi, H.; Mima, K. [Institute of Laser Engineering, Osaka University, 2-6 Yamada-oka, Suita, Osaka 565-0871 (Japan); Ozaki, N.; Kimura, T.; Miyanishi, K.; Kodama, R. [Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka 565-0871 (Japan); Sakaiya, T. [Graduate School of Science, Osaka University, 1-1 Machikaneyama-cho, Toyonaka, Osaka 560-0043 (Japan); Sunahara, A. [Institute for Laser Technology, 2-6 Yamada-oka, Suita, Osaka 565-0871 (Japan)

2010-03-15

338

Aerosol Sources, Absorption, and Intercontinental Transport: Synergies among Models, Remote Sensing, and Atmospheric Measurements  

NASA Technical Reports Server (NTRS)

Aerosol climate forcing is one of the largest uncertainties in assessing the anthropogenic impact on the global climate system. This uncertainty arises from the poorly quantified aerosol sources, especially black carbon emissions, our limited knowledge of aerosol mixing state and optical properties, and the consequences of intercontinental transport of aerosols and their precursors. Here we use a global model GOCART to simulate atmospheric aerosols, including sulfate, black carbon, organic carbon, dust, and sea salt, from anthropogenic, biomass burning, and natural sources. We compare the model calculated aerosol extinction and absorption with those quantities from the ground-based sun photometer measurements from AERONET at several different wavelengths and the field observations from ACE-Asia, and model calculated total aerosol optical depth and fine mode fractions with the MODIS satellite retrieval. We will also estimate the intercontinental transport of pollution and dust aerosols from their source regions to other areas in different seasons.

Chin, Mian; Ginoux, Paul; Dubovik, Oleg; Holben, Brent; Kaufman, Yoram; chu, Allen; Anderson, Tad; Quinn, Patricia

2003-01-01

339

Aerosol Sources, Absorption, and Intercontinental Transport: Synergies Among Models, Remote Sensing, and Atmospheric Measurements  

NASA Technical Reports Server (NTRS)

Aerosol climate forcing is one of the largest uncertainties in assessing the anthropogenic impact on the global climate system. This uncertainty arises from the poorly quantified aerosol sources, especially black carbon emissions, our limited knowledge of aerosol mixing state and optical properties, and the consequences of intercontinental transport of aerosols and their precursors. Here we use a global model GOCART to simulate atmospheric aerosols, including sulfate, black carbon, organic carbon, dust, and sea salt, from anthropogenic, .biomass burning, and natural sources. We compare the model calculated aerosol extinction and absorption with those quantities from the ground-based sun photometer measurements from AERON" at several different wavelengths and the field observations from ACE-Asia, and model calculated total aerosol optical depth and fine mode fractions with the MODIS satellite retrieval. We will also estimate the intercontinental transport of pollution and dust aerosols from their source regions to other areas in different seasons.

Chin, Mian; Chu, Allen; Levy, Robert; Remer, Lorraine; Kaufman, Yoram; Dubovik, Oleg; Holben, Brent; Eck, Tom; Anderson, Tad; Quinn, Patricia

2004-01-01

340

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

341

A Fluorescence Method for Measurement of Glucose Transport in Kidney Cells  

PubMed Central

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

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

2011-01-01

342

Expanded Transportation Performance Measures to Supplement Level of Service (LOS) for Growth Management and Transportation Impact Analysis.  

National Technical Information Service (NTIS)

Growth management has attempted to manage the pace of development while providing or improving transportation services to users. However, these efforts have largely focused on automobile travelers using as a primary evaluation tool for growth management t...

K. Lim L. Elefteriadou P. C. Tice R. L. Steiner S. Srinivasan

2012-01-01

343

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

NASA Astrophysics Data System (ADS)

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

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

2011-10-01

344

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

345

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

PubMed Central

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

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

2013-01-01

346

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

SciTech Connect

In situ spatial and temporal temperature measurements of pristine fused silica surfaces heated with a 10.6 {micro}m CO{sub 2} laser were obtained using an infrared radiation thermometer based on a Mercury Cadmium Telluride (MCT) camera. Laser spot sizes ranged from 250 {micro}m to 1000 {micro}m diameter with peak axial irradiance levels of 0.13 to 16 kW/cm{sup 2}. For temperatures below 2800K, the measured steady-state surface temperature is observed to rise linearly with both increasing beam size and incident laser irradiance. The effective thermal conductivity estimated over this range was approximately 2W/mK, in good agreement with classical calculations based on phonon heat capacities. Similarly, time-dependent temperature measurements up to 2000K yielded thermal diffusivity values which were close to reported values of 7 x 10{sup -7} m{sup 2}/s. Above {approx}2800K, the fused silica surface temperature asymptotically approaches 3100K as laser power is further increased, consistent with the onset of evaporative heat losses near the silica boiling point. These results show that in the laser heating regime studied here, the T{sup 3} temperature dependent thermal conductivity due to radiation transport can be neglected, but at temperatures above 2800K heat transport due to evaporation must be considered. The thermal transport in fused silica up to 2800K, over a range of conditions, can then be adequately described by a linear diffusive heat equation assuming constant thermal properties.

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

2009-07-07

347

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

NASA Astrophysics Data System (ADS)

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

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

2012-05-01

348

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

349

Velocity profile measurements in high Reynolds number Taylor-Couette flow for pure outer-cylinder rotation  

NASA Astrophysics Data System (ADS)

Using Laser Doppler Anemometry, we measured azimuthal and axial velocity profiles inside the gap of a Taylor-Couette apparatus, spinning only the outer cylinder at a varying Reynolds number from 1.4 x10^5 to 1.4 x10^6. The system has a radius ratio of 0.716 and an aspect ratio of 11.68, and the end plates are attached to the outer cylinder. The azimuthal profiles were found to be notably different from the laminar velocity profile due to the influence of the end plates. We analyzed the end effects by studying the Ekman and Stewartson boundary layer dynamics in Taylor-Couette flow.

Huisman, Sander; van Gils, Dennis; Sun, Chao; van Heijst, Gertjan; Lohse, Detlef

2010-11-01

350

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

351

Cross-shore sediment transport measurements at the beach of Sète, Gulf of Lion  

NASA Astrophysics Data System (ADS)

The observation of the cross-shore sediment displacement in the off-shore direction is one of the objectives of the repeated measurement campaigns that took place at the beach of Sète, Gulf of Lion (NW Mediterranean Sea). The site has been instrumented in 1999, 2000 and more recently in 2009 using wave recording current meters, pressure sensor arrays, ADVs and bottom mounted ADCPs in the depth range 2-6m. It is characterized by micro-tidal condition. The location of Sète is one of the experimental sites chosen to study the phenomenon of coastal erosion that largely affects the sandy coast of the Gulf of Lion. Waves generated by winds coming from the southwest-south-southeast directions have been identified as the main forcing for sediment displacement. Moreover, we observe that such process occurs during storm condition where the cross-shore velocity is >~30cm/sec. During good weather, the data of the cross-shore velocity cannot be trusted due to the very small values. In addition, sediment transport computation shows that the dominant direction for cross-shore sediment displacement is off-shore during storm conditions, and its magnitude largely exceeds the transport in the long-shore direction. Thus, we conclude that in the particular condition of a micro-tidal beach, the off-shore sediment transport due to wind-waves has a dominant role in costal erosion.

Brambilla, E.; Bouchette, F.; Certain, R.; Robin, N.; Ferrer, P.; Sylaios, G.

2009-12-01

352

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

353

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

PubMed Central

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.

2014-01-01

354

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.

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

355

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

PubMed Central

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

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

2013-01-01

356

First measurements of the two-dimensional horizontal wave number spectrum from CCD images of the nightglow  

NASA Astrophysics Data System (ADS)

A narrow wavelength band CCD camera, built at Aerospace, has been used to obtain images of the OH Meinel (6,2) band and the O2 atmospheric (0,1) band nightglow. The field of view of the camera is approximately 100 by 100 km at an altitude of 90 km, the nominal height of the nightglow. It is shown how Fourier techniques can be applied to these data to optimally smooth the images, to identify the presence of monochromatic waves, and to obtain both the one-dimensional and, for the first time, the two-dimensional horizontal wave number spectrum of gravity waves passing through the emission layers. Both measures of the spectrum depend, to a certain extent, on a technique which makes use of Krassovsky's ? ratio. These techniques are applied to sample data taken from May 9, 1989, during the Arecibo Initiative in Dynamics of the Atmosphere (AIDA) campaign in Puerto Rico, and from the recent Collaborative Observations Regarding the Nightglow (CORN) campaign in Illinois. While future papers will describe these data in more detail, a brief comparison is made with recent models of the two-dimensional horizontal wave number spectra presented by Gardner et al. (1993) and Gardner (1994).

Hecht, J. H.; Walterscheid, R. L.; Ross, M. N.

1994-06-01

357

Temperature dependent spin transport properties of platinum inferred from spin Hall magnetoresistance measurements  

NASA Astrophysics Data System (ADS)

We study the temperature dependence of the spin Hall magnetoresistance (SMR) in yttrium iron garnet/platinum hybrid structures via magnetization orientation dependent magnetoresistance measurements. Our experiments show a decrease of the SMR magnitude with decreasing temperature. Using the sensitivity of the SMR to the spin transport properties of the normal metal, we interpret our data in terms of a decrease of the spin Hall angle in platinum from 0.11 at room temperature to 0.075 at 10 K, while the spin diffusion length and the spin mixing conductance of the ferrimagnetic insulator/normal metal interface remain almost constant.

Meyer, Sibylle; Althammer, Matthias; Geprägs, Stephan; Opel, Matthias; Gross, Rudolf; Goennenwein, Sebastian T. B.

2014-06-01

358

State DOT Public Transportation Performance Measures: State of the Practice and Future Needs. Research Results Digest 361.  

National Technical Information Service (NTIS)

State departments of transportation (DOTs) are increasingly using performance measures to improve their planning, construction, and operations and in response to greater need for accountability. Some state DOTs have developed sophisticated agency wide str...

J. Crossett M. Grant S. Suter S. Trainor T. Plaskon

2011-01-01

359

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

USGS Publications Warehouse

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

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

2008-01-01

360

Development of vacuum ultraviolet absorption spectroscopy system for wide measurement range of number density using a dual-tube inductively coupled plasma light source  

NASA Astrophysics Data System (ADS)

A vacuum ultraviolet absorption spectroscopy system for a wide measurement range of atomic number densities is developed. Dual-tube inductively coupled plasma was used as a light source. The probe beam profile was optimized for the target number density range by changing the mass flow rate of the inner and outer tubes. This system was verified using cold xenon gas. As a result, the measurement number density range was extended from the conventional two orders to five orders of magnitude.

Kuwahara, Akira; Matsui, Makoto; Yamagiwa, Yoshiki

2012-12-01

361

Development of vacuum ultraviolet absorption spectroscopy system for wide measurement range of number density using a dual-tube inductively coupled plasma light source  

SciTech Connect

A vacuum ultraviolet absorption spectroscopy system for a wide measurement range of atomic number densities is developed. Dual-tube inductively coupled plasma was used as a light source. The probe beam profile was optimized for the target number density range by changing the mass flow rate of the inner and outer tubes. This system was verified using cold xenon gas. As a result, the measurement number density range was extended from the conventional two orders to five orders of magnitude.

Kuwahara, Akira; Matsui, Makoto; Yamagiwa, Yoshiki [Department of Mechanical Engineering, Shizuoka University, 3-5-4 Johoku, Naka-ku, Hamamatsu 432-8561, Shizuoka (Japan)

2012-12-15

362

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

363

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

NASA Astrophysics Data System (ADS)

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

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

2010-12-01

364

The Australian methane budget: Interpreting surface and train-borne measurements using a chemistry transport model  

NASA Astrophysics Data System (ADS)

We investigate the Australian methane budget from 2005-2008 using the GEOS-Chem 3D chemistry transport model, focusing on the relative contribution of emissions from different sectors and the influence of long-range transport. To evaluate the model, we use in situ surface measurements of methane, methane dry air column average (XCH4) from ground-based Fourier transform spectrometers (FTSs), and train-borne surface concentration measurements from an in situ FTS along the north-south continental transect. We use gravity anomaly data from Gravity Recovery and Climate Experiment to describe the spatial and temporal distribution of wetland emissions and scale it to a prior emission estimate, which better describes observed atmospheric methane variability at tropical latitudes. The clean air sites of Cape Ferguson and Cape Grim are the least affected by local emissions, while Wollongong, located in the populated southeast with regional coal mining, samples the most locally polluted air masses (2.5% of the total air mass versus <1% at other sites). Averaged annually, the largest single source above background of methane at Darwin is long-range transport, mainly from Southeast Asia, accounting for ˜25% of the change in surface concentration above background. At Cape Ferguson and Cape Grim, emissions from ruminant animals are the largest source of methane above background, at approximately 20% and 30%, respectively, of the surface concentration. At Wollongong, emissions from coal mining are the largest source above background representing 60% of the surface concentration. The train data provide an effective way of observing transitions between urban, desert, and tropical landscapes.

Fraser, Annemarie; Chan Miller, Christopher; Palmer, Paul I.; Deutscher, Nicholas M.; Jones, Nicholas B.; Griffith, David W. T.

2011-10-01

365

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

SciTech Connect

Critical Deposition Velocity (CDV) is an important design and operational parameter in slurry transport. Almost all existing correlations that are used to predict this parameter have been obtained experimentally from slurry transport tests featuring single solid species in the slurry mixture. No correlations have been obtained to describe this parameter when the slurry mixture contains more than one solid species having a wide range of specific gravities, particle size distributions, and volume concentrations within the overall slurry mixture. There are no physical or empirical bases that can justify the extrapolation or modification of the existing single species correlations to include all these effects. New experiments must be carried out to obtain new correlations that would be suited for these types of slurries, and that would clarify the mechanics of solids deposition as a function of the properties of the various solid species. Our goal in this paper is to describe a robust experimental technique for the accurate determination of the critical deposition velocity associated with the transport of slurries in horizontal or slightly inclined pipes. Because of the relative difficulty encountered during the precise determination of this useful operational parameter, it has been the practice to connect it with some transitional behavior of more easily measurable flow parameters such as the pressure drop along the slurry pipeline. In doing so, the critical deposition velocity loses its unique and precise definition due to the multitude of factors that influence such transitional behaviors. Here, data has been obtained for single species slurries made up of washed garnet and water and flowing through a 1- inch clear pipe. The selected garnet had a narrow particle size distribution with a mean diameter of 100 mm, approximately. The critical deposition velocity was measured for garnet/water slurries of 10, 20, and 30 percent solids concentration by volume.

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

2001-03-01

366

Transport and magnetization ac losses of ROEBEL assembled coated conductor cables: measurements and calculations  

NASA Astrophysics Data System (ADS)

Many superconductor applications require cables with a high current capacity. This is not feasible with single-piece coated conductors because their ac losses are too large. Therefore, it is necessary to develop superconducting cables with a high current capacity and low ac losses. One promising solution is given by ROEBEL cables. We assembled three ROEBEL cables from commercial YBCO coated conductors. The cables have the same width but a different number of strands, which results in different aspect ratios and current capacities. We experimentally studied their ac losses under a transport current or a perpendicular magnetic field. In addition, we performed numerical calculations, which agree with the experiments, especially for the transport case. We found that in the cables there is good current sharing between the strands. We also found that stacking the strands reduces the magnetization losses. For a given critical current, thicker cables have lower magnetization ac losses. In addition, a conducting matrix is not required for a good current sharing between strands.

Terzieva, Stanimira; Vojen?iak, Michail; Pardo, Enric; Grilli, Francesco; Drechsler, Antje; Kling, Andrea; Kudymow, Andrej; Gömöry, Fedor; Goldacker, Wilfried

2010-01-01

367

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

PubMed

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

Fan; Moros; Straube

2000-06-01

368

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

NASA Astrophysics Data System (ADS)

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

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

2009-04-01

369

Variable-range hopping transport and Hall effect measurements in electrolyte-gated P3HT  

NASA Astrophysics Data System (ADS)

Extensive charge transport measurements (1.5 -- 250 K) at gate-tuned hole concentrations between 1*1^20 and 9*10^20 cm-3 have been made on a single ion-gel gated poly-(3-hexylthiophene) (P3HT) thin film transistor. We report observation of a robust Hall effect, having rational trends with magnetic field, gate voltage, and temperature, and yielding hole concentrations close to those measured via the charging current. At high doping we observe transitions from apparent band transport, to 3D Mott variable range hopping (VRH), to Efros-Shklovskii (ES) VRH on cooling. At lower doping ES VRH is observed at all temperatures. A detailed analysis of the temperature and field-dependence of the VRH resistivity provides information on the localization length and dielectric constant as a function of doping, providing significant insights into the approach to the insulator-metal transition in this system and the nature of the Coulomb-gapped density of states. Work at UMN supported by NSF MRSEC

Wang, Shun; Ha, Mingjing; Manno, Michael; Frisbie, C. Daniel; Leighton, C.

2012-02-01

370

Propagation characteristics of surface acoustic waves in single-electron transport devices and the electrical measurement.  

PubMed

We focused on investigating the propagation characteristics of surface acoustic waves (SAWs) in SAW-based single-electron-transport (SAW/SET) devices. SAW/SET devices operating in the gigahertz frequency range were fabricated on a GaAs/Al(x)Ga(1-x)As heterostructure. The transmittance and reflection performances of SAW/SET devices were obtained via the electrical measurement. Modeling based on coupling-of-modes theory was introduced to analyze SAW/ SET devices. Based on this model, many second-order effects such as propagation loss and the mechanical and electrical loadings caused by electrode perturbation of the surface were taken into account. Multiple-transit reflections of SAWs were also contained in the calculation. The calculated transmittance and reflection performances were in good agreement with the measured data. Furthermore, we proposed four interference types which could satisfactorily explain the periodic oscillations presented in the acoustoelectric current versus frequency characteristics. PMID:21768029

Zhang, Chuan-Yu; Gao, Jie; Li, Hong; Song, Li; Lu, Chuan

2011-07-01

371

Measurement of mitochondrial Ca2+ transport mediated by three transport proteins: VDAC1, the Na+/Ca2+ exchanger, and the Ca2+ uniporter.  

PubMed

Ca(2+) is a ubiquitous cellular signal, with changes in intracellular Ca(2+) concentration not only stimulating a number of intercellular events but also triggering cell death pathways, including apoptosis. Mitochondrial Ca(2+) uptake and release play pivotal roles in cellular physiology by regulating intracellular Ca(2+) signaling, energy metabolism and cell death. Ca(2+) transport across the inner and outer mitochondrial membranes is mediated by several proteins, including channels, antiporters, and a uniporter. In this article, we present the background to several methods now established for assaying mitochondrial Ca(2+) transport activity across both mitochondrial membranes. The first of these is Ca(2+) transport mediated by the outer mitochondrial protein, the voltage-dependent anion-selective channel protein 1 (VDAC1, also known as porin 1), both as a purified protein reconstituted into a planar lipid bilayer (PLB) or into liposomes and as a mitochondrial membrane-embedded protein. The second method involves isolated mitochondria for assaying the activity of an inner mitochondrial membrane transport protein, the mitochondrial Ca(2+) uniporter (MCU) that transports Ca(2+) and is powered by the steep mitochondrial membrane potential. In the event of Ca(2+) overload, this leads to opening of the mitochondrial permeability transition pore (MPTP) and cell death. The third method describes how Na(+)-dependent mitochondrial Ca(2+) efflux mediated by mitochondrial NCLX, a member of the Na(+)/Ca(2+) exchanger superfamily, can be assayed in digitonin-permeabilized HEK-293 cells. The Ca(2+)-transport assays can be performed under various conditions and in combination with inhibitors, allowing detailed characterization of the transport activity of interest. PMID:24492769

Ben-Hail, Danya; Palty, Raz; Shoshan-Barmatz, Varda

2014-02-01

372

Mass measurements using isotopically labeled solvents reveal the extent of solvent transport during redox in thin films on electrodes  

SciTech Connect

Transport of solvent during the redox reactions of thin films on electrodes has been identified as a possible influence on both the thermodynamic and kinetic aspects of their electrochemical responses. A variety of methods has been used in attempts to measure solvent content of these films, including ellipsometry and profilimetry. However, those techniques which rely on measurement of thickness suffer from inability to deconvolute the contributions to swelling (or deswelling) from ion and solvent transport. Thus, the situation remains one in which speculation abounds, but accurate measurements are unavailable. In this communication, the authors report on the application of the quartz crystal microbalance (QCM) technique to the determination of solvent transport during redox in thin films of nickel ferrocyanide (the nickel analogue of Prussian Blue) by comparing the difference in the total mass change (comprised of contributions from both ion and solvent transport) which results from use of isotopically substituted solvent. To their knowledge, these experiments represent the first accurate, unambiguous measurements of solvent transport in thin films on electrodes. It is especially significant that these measurements are made in the presence of simultaneous ion transport.

Lasky, S.J.; Buttry, D.A.

1988-08-31

373

Effect of transportation, time of sampling, and lymphocyte numbers on gamma interferon response to Mycobacterium bovis in cattle at time of slaughter.  

PubMed

Adapting the gamma interferon (IFN?) assay for tuberculosis screening at points-of-concentration of cattle would improve global efforts to eradicate bovine tuberculosis. Two separate studies were conducted to evaluate if transportation of cattle, the time of blood collection, and total lymphocyte count affects the retention of a positive IFN? assay result during slaughter of cattle experimentally sensitized with inactivated Mycobacterium bovis. Study 1 evaluated IFN? assay responses to M. bovis and Mycobacterium avium stimulations in 5 cows (4 sensitized and 1 control) at the housing facility, after a 30-min transport to the slaughter facility, immediately before stunning, at commencement of exsanguination, and at 5 min after exsanguination commenced. Study 2 evaluated IFN? assay responses to Mycobacterium antigen stimulations and total lymphocyte count in blood collected from 5 steers (4 sensitized and 1 control) at the housing facility, at commencement of exsanguination and at 2 successive 1-min intervals. The results indicated that blood obtained from sensitized cattle at commencement of exsanguination was more likely to remain positive than blood collected at successive time points; hence the time of blood collection is crucial to obtaining a useful IFN? assay result for bovine tuberculosis at slaughter. The lymphocyte count progressively declined following exsanguination, and this decline might contribute to the reduction in the measured IFN?. To compensate for the reduction in IFN? production, a different set of positive cutoff values might be needed for blood collected at exsanguination. The current findings provide useful preliminary information necessary for making changes to the interpretation of the IFN? assay on blood collected during exsanguination. PMID:23417080

Okafor, Chika C; Grooms, Daniel L; Bolin, Steven R; Gravelyn, Tara D; Kaneene, John B

2013-03-01

374

Measurements of Tidally Forced Bedforms, Sediment Transport, Flow and Turbulence at New River Inlet, NC  

NASA Astrophysics Data System (ADS)

Observations of bedforms and near-bed hydrodynamics in New River Inlet, NC reveal a highly temporally and spatially variable bedform field with rapid migration rates. Time series measurements were conducted at two tidally dominated stations with instrumented frames, and spatial surveys were conducted with a small vessel and REMUS AUV. The spatial surveys showed that the bedforms were largest in the ~3 m deep tidal channels, with wavelengths of ~4 m and heights of ~40 cm. These channels also had the strongest tidal flows with ebb directed velocities of up to 1.5 m/s, and coarsest sand. On the finer grained shoals, bedforms were smaller with wavelengths less than 1 m. Time series measurements of the bedforms taken with rotary sidescan and pencil beam sonars revealed most of the variability occurred at semi-diurnal tidal and spring-neap tidal time scales. The largest ~4 m wavelength bedforms only occurred on spring tides and bedforms were smaller during neap tides. At the measurement sites, the flow and bedforms were tidally dominated with the bedforms responding to wave forcing less than 20% of the time during periods of flood and high tides with energetic wave forcing. On individual tidal cycles, the bedforms changed from ebb directed asymmetry to flood direct asymmetry and migrated approximately one wavelength. The relationship between flow asymmetry, with ebb dominated flows, and bedform migration asymmetry will be examined. Flow and turbulence above the bedforms was measured with a multi-frequency pulse coherent Doppler profiler and two ADVs. The velocity profiles show pronounced wake velocity deficits when large bedform crests were present just upstream of the profiler. Turbulence levels as a function of bedform geometry, location, and forcing flow will be examined. The measurements of flow and turbulence, combined with bedform geometry and migration measurements and suspended sediment transport measurements from a 3-frequency acoustic backscatter system will allow analysis of the dominant modes and directions of sediment transport.Rotary sidescan image of bedforms 2.7 hours before max. ebb flow showing small bedforms superimposed on the large scale features during a flow of 0.7 m/s, shorty before sheet flow conditions occurred. The white lines show the location of a bedform crest at 1 hour intervals, indicating migration rates up to 2 m/hr.

Traykovski, P.; Geyer, W. R.

2012-12-01

375

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

NASA Astrophysics Data System (ADS)

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

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

2012-12-01

376

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

NASA Astrophysics Data System (ADS)

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

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

2006-12-01

377

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

NASA Astrophysics Data System (ADS)

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

Albrecht, Daniel; Reitenbach, Viktor

2014-05-01

378

Determination of Kinetic Parameters of Enzyme-Catalyzed Reaction A + B + C -> Products with the Minimum Number of Velocity Measurements  

PubMed Central

Rapid-equilibrium rate equations are derived for the five different mechanisms for the enzymatic catalysis of A + B + C ? products using a computer. These rate equations are used to determine the minimum number of velocities required to estimate the values of the kinetic parameters. The rate equation for the completely ordered mechanism involves four kinetic parameters, and the rate equation for the completely random mechanism involves eight kinetic parameters. Therefore, the four to eight kinetic parameters can be estimated by determining four to eight velocities and solving four to eight simultaneous equations. General recommendations are made as to the choices of triplets of substrate concentrations {[A], [B], [C]} to be used to determine the velocities. The effects of 5% errors in the measured velocities, one at a time, are calculated and are summarized in tables. Calculations of effects of experimental errors are useful in choosing the triplets of substrate concentrations to be used to obtain the most accurate values of the kinetic parameters. When the kinetic parameters for A + B + C ? products are to be determined for the first time, it is recommended that the program for the completely random mechanism be used because it can identify the mechanism and determine the kinetic parameters in one operation.

2009-01-01

379

Trial of a rapid measurement method by absorption photometer for the determination of the number of bacteria in the air.  

PubMed

A quick method to measure the number and the concentration of airborne bacteria was examined by combining bacteria staining with a crystal violet solution and absorptiometry. The suspension of the bacteria isolated from the environment was adjusted to 3.0 × 10(8) colony forming units (CFU) / ml in E. coli equivalent, and a 10-fold dilution series was created. After centrifugation of each bacterial suspension, the supernatant was removed and the bacteria were stained by adding a crystal violet solution. The sample was centrifuged again, and the supernatant was collected and named the unabsorbed sample. The residual bacteria were washed two times, and ethanol was added to the stained cells. The recovered solution collected by centrifugation of the cells was named the recovered sample.The chemicals in the samples were examined by high performance liquid chromatography, but no peak could be observed without the staining material. Absorption spectrophotometry showed that the determination limit of bacteria in the unabsorbed samples was 3.0 × 10(7) CFU / ml in E. coli equivalent and that in the recovered samples was 3.0 × 10(8) CFU / ml, indicating that the unabsorbed sample had a lower determination limit. PMID:24930881

Hinoue, Mitsuo; Ishimatsu, Sumiyo; Hori, Hajime

2014-06-01

380

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

SciTech Connect

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

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

1989-03-21

381

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

NASA Astrophysics Data System (ADS)

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

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

2011-07-01

382

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

383

Ethanol transport in Zymomonas mobilis measured by using in vivo nuclear magnetic resonance spin transfer.  

PubMed Central

For the first time, unidirectional rate constants of ethanol diffusion through the lipid membrane of a microorganism, the bacterium Zymomonas mobilis, were determined, thus replacing indirect inferences with direct kinetic data. The rate constants k1 (in to out) were 6.8 +/- 0.4s(-1) at 29 degrees C and 2.7 +/- 0.3s(-1) at 20 degrees C. They were determined by using 1H selective nuclear magnetic resonance spin magnetization transfer. The measurements were done on l-ml cell suspensions. No addition of radiotracers, withdrawing of aliquots, physical separation methods, or chemical manipulations were required. Until now, the rate constants of ethanol transport in microorganisms have been unknown because ethanol diffuses through the cytoplasmic membrane too quickly for radiolabel approaches. Net velocities of ethanol exchange were calculated from unidirectional rate constants and cytoplasmic volume, which was also determined with the same nuclear magnetic resonance experiments. The results (i) confirmed that ethanol would not be rate limiting during the conversion of glucose by Z. mobilis and (ii) indicated that ethanol can serve as an in vivo marker of cytoplasmic volume changes. This was verified by monitoring for the first time the changes of both cytoplasmic volume and extracytoplasmic and cytoplasmic concentrations of alpha and beta anomers of D-glucose in cell suspensions of a microorganism. These findings may open up new possibilities for kinetic studies of ethanol and sugar transport in Z. mobilis and other organisms.

Schoberth, S M; Chapman, B E; Kuchel, P W; Wittig, R M; Grotendorst, J; Jansen, P; DeGraff, A A

1996-01-01

384

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

385

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

386

Opacity and Transport Measurements Reveal That Dilute Plasma Models of Sonoluminescence Are Not Valid  

NASA Astrophysics Data System (ADS)

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.

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

2012-03-01

387

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

388

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

NASA Astrophysics Data System (ADS)

From 1994 to 2011, instruments measuring ocean currents (Acoustic Doppler Current Profilers; ADCPs) have been moored on a section crossing the Faroe-Shetland Channel. Together with CTD (Conductivity Temperature Depth) measurements from regular research vessel occupations, they describe the flow field and water mass structure in the channel. Here, we use these data to calculate the average volume transport and properties of the flow of warm water through the channel from the Atlantic towards the Arctic, termed the Atlantic inflow. We find the average volume transport of this flow to be 2.7 ± 0.5 Sv (1 Sv = 106 m3 s-1) between the shelf edge on the Faroe side and the 150 m isobath on the Shetland side. The average heat transport (relative to 0 °C) was estimated to be 107 ± 21 TW (1 TW = 1012 W) and the average salt import to be 98 ± 20 × 106 kg s-1. Transport values for individual months, based on the ADCP data, include a large level of variability, but can be used to calibrate sea level height data from satellite altimetry. In this way, a time series of volume transport has been generated back to the beginning of satellite altimetry in December 1992. The Atlantic inflow has a seasonal variation in volume transport that peaks around the turn of the year and has an amplitude of 0.7 Sv. The Atlantic inflow has become warmer and more saline since 1994, but no equivalent trend in volume transport was observed.

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

2013-07-01

389

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

NASA Astrophysics Data System (ADS)

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

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

2013-01-01

390

Measurement of resistance to solute transport across surfactant-laden interfaces using a Fluorescence Recovery After Photobleaching (FRAP) technique  

NASA Technical Reports Server (NTRS)

A noninvasive fluorescence recovery after photobleaching (FRAP) technique is under development to measure interfacial transport in two phase systems without disturbing the interface. The concentration profiles of a probe solute are measured in both sides of the interface by argon-ion laser, and the system relaxation is then monitored by a microscope-mounted CCD camera.

Browne, Edward P.; Nivaggioli, Thierry; Hatton, T. Alan

1994-01-01

391

Measuring transport coefficients necessary for the description of coupled two-phase flow of immiscible fluids in porous media  

Microsoft Academic Search

In the simplist cases of coupled two-phase flow of immiscible fluids in porous media, the governing equations usually are written to show that there are four independent transport coefficients that implicitly have to be separately measured. The analysis presented here accordingly indicates that two types of known experiments involving two measurements apiece are needed at each fluid saturation condition in

Walter Rose

1988-01-01

392

Increasing the productivity of the nation's urban transportation infrastructure: Measures to increase transit use and carpooling. Final report  

Microsoft Academic Search

The report surveys the growing use of bus and carpool priority measures to increase the productivity of the nation's transportation infrastructure. While it identifies a wide variety of priority measures, the report principally focuses on the planning and operation of exclusive and shared busways and high occupancy vehicle (HOV) facilities. It presents a variety of case studies describing the implementation

J. F. Kain; R. Gittell; A. Daniere; S. Daniel; T. Somerville

1992-01-01

393

Tiltakspakker for Kollektivtransport 1996-2000> Samfunnsokonomiske Analyser (Public Transport Packages of Measures 1996-2000. Economic Evaluation).  

National Technical Information Service (NTIS)

This report is a part of a series of evaluations of the Norwegian urban public transport packages of measures that were implemented in 1996-2000. It looks specifically at the economic performance of the packages of measures, i.e. costs and benefits of the...

N. Fearnley A. Nossum

2004-01-01

394

Twin sample chamber for simultaneous comparative transport measurements in a diamond anvil cell  

NASA Astrophysics Data System (ADS)

In static high pressure experiments, performed within a diamond anvil cell (DAC), several different methods of thermometry may be employed to determine the temperature of the sample. Due to different DAC designs or particular experimental designs or goals, uncertainties in the determination of the temperature of a given sample exist. To overcome the inaccuracy in comparing the temperature dependence of transport properties of different materials at high pressure, we have used a novel design of resistivity measurement in a twin sample chamber built on an insulated gasket in a DAC. In this design, the transport properties of two samples will be measured simultaneously and therefore the two samples will always be in the same relative temperatures. The uncertainties in the temperatures of the two samples will be exactly the same and therefore their relative phase diagram will be compared precisely. The pressures of the chambers can be slightly different and is easily determined by the ruby pieces placed in each chamber. To demonstrate the feasibility of this method we have compared the superconducting properties of two YBa2Cu3O7-x (0 <= x <= 0.65) samples with slightly different superconducting transition temperatures at ambient pressure as a function of pressures up to 11 GPa. The upper limit of the pressure achieved using this design would be lower than single chamber gaskets. The highest achievable pressure, as in a conventional single hole setup, depends upon the thickness of the gasket, the culet size, the size, and symmetry of the sample chamber. For the twin chamber, it also depends upon the separation of the holes from each other as well as from the edge of the culet.

Schaeffer, Anne Marie J.; Deemyad, Shanti

2013-09-01

395

Relationship Between Skid Resistance Numbers Measured with Ribbed and Smooth Tire and Wet-Accident Locations (Final Report).  

National Technical Information Service (NTIS)

Due to a recent strategic initiative adopted by the Ohio Department of Transportation (ODOT), there is a need to determine if skid resistance testing results can be correlated to wet weather crash data in Ohio. Specifically, the results of testing conduct...

2008-01-01

396

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

NASA Technical Reports Server (NTRS)

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

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

1982-01-01

397

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

NASA Astrophysics Data System (ADS)

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

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

2011-11-01

398

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.

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

1993-01-01

399

worker certain content 131I thyroid monitored whole body counter under fixed conditions geometry counting time. net number measured gamma counts (background subtracted) thyroid initial 1129  

EPA Pesticide Factsheets

Did you mean: worker certain content 131I thyroid monitored whole body counter under fixed conditions geometry counting time. net number measured gamma counts (background subtracted) thyroid initial 1129 ?

400

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

401

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

402

Apparatus and method for detecting and measuring changes in linear relationships between a number of high frequency signals  

DOEpatents

An electronic measurement circuit is disclosed for high speed comparison of the relative amplitudes of a predetermined number of electrical input signals independent of variations in the magnitude of the sum of the signals. The circuit includes a high speed electronic switch that is operably connected to receive on its respective input terminals one of said electrical input signals and to have its common terminal serve as an input for a variable-gain amplifier-detector circuit that is operably connected to feed its output to a common terminal of a second high speed electronic switch. The respective terminals of the second high speed electronic switch are operably connected to a plurality of integrating sample and hold circuits, which in turn have their outputs connected to a summing logic circuit that is operable to develop first, second and third output voltages, the first output voltage being proportional to a predetermined ratio of sums and differences between the compared input signals, the second output voltage being proportional to a second summed ratio of predetermined sums and differences between said input signals, and the third output voltage being proportional to the sum of signals to the summing logic circuit. A servo system that is operably connected to receive said third output signal and compare it with a reference voltage to develop a slowly varying feedback voltage to control the variable-gain amplifier in said common amplifier-detector circuit in order to make said first and second output signals independent of variations in the magnitude of the sum of said input signals. 2 figures.

Bittner, J.W.; Biscardi, R.W.

1991-03-19

403

Aftebody Drag and Base Pressure Measurements on a Body of Revolution at Angles of Incidence Up to alpha Equals 25 Deg at Subsonic and Transonic Mach Numbers.  

National Technical Information Service (NTIS)

Base pressure and afterbody drag measurements were performed in a wind tunnel. The Mach number had values from 0.5 to 1.0. The Reynolds number based on the model diameter was 340,000. Results show the influence of the boat-tail angle, the boat-tail length...

M. Tanner

1978-01-01

404

Laboratory measurements of the direction of sediment transport on transverse alluvial-bed slopes  

Microsoft Academic Search

Laboratory experiments have been conducted to provide data for modelling the direction of sediment transport on a transverse sloping alluvial bed. Conditions with prevailing bed-load transport, and conditions in which a significant part of the bed material is transported as suspended-load are studied. The effect of a sloping bed on the direction of sediment transport is determined by conducting bed-levelling

A. M. Talmon; N. Struiksma; M. C. L. M. Van Mierlo

1995-01-01

405

Electrical conductivity and transport properties of cement-based materials measured by impedance spectroscopy  

NASA Astrophysics Data System (ADS)

The use of Impedance Spectroscopy (IS) as a tool to evaluate the electrical and transport properties of cement-based materials was critically evaluated. Emphasis was placed on determining the efficacy of IS by applying it as a tool to investigate several families of cement-based materials. Also, the functional aspects of electroding and null corrections were also addressed. The technique was found to be advantageous for these analyses, especially as a non-destructive, in-situ, rapid test. Moreover, key insights were gained into several cement-based systems (e.g., cement mortars and oil-well grouts) as well as the effect that certain testing techniques can have on materials (e.g., the rapid chloride permeability test). However, some limitations of IS were identified. For instance, improper electroding of samples can lead to erroneous results and incorrect interpretations for both two-point and multi-point measurements. This is an area of great importance, but it has received very little attention in the literature. Although the analysis of cement/electrode techniques is in its infancy, much progress was made in gaining a full understand of how to properly and reliably connect electrodes to cement-based materials. Through the application of IS to materials such as oil-well grouts, cement mortars and concretes, a great deal of valuable information about the effectiveness of IS has been gained. Oil-well cementing is somewhat limited by the inability to make measurements in the well-bore. By applying IS to oil-well grouts in a laboratory environment, it was demonstrated that IS is a viable technique with which to test the electrical and transport properties of these materials in-situ. Also, IS was shown to have the ability to measure the electrical conductivity of cement mortars with such accuracy, that very subtle changes in properties can be monitored and quantified. Through the use of IS and theoretical models, the complex interplay between the interfacial transition zone (ITZ) and evolving cement matrix was sorted out. Finally, IS was shown to be able to measure the effect that the rapid chloride permeability test has on samples ranging from a neat paste to a high-strength concrete. The effect of the high current densities, high heat and/or sample preparation on the samples was documented and qua