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1

Recent theoretical and experimental results on inertial fusion energy physics  

NASA Astrophysics Data System (ADS)

We study with ARWEN code a target design for ICF based on jet production. ARWEN is 2D Adaptive Mesh Refinement fluid dynamic and multigroup radiation transport. We are designing, by using also ARWEN, a target for laboratory simulation of astrophysical phenomena. We feature an experimental device to reproduce collisions of two shock waves, scaled to roughly represent cosmic supernova remnants. ANALOP code uses parametric potentials fitting to self-consistent potentials, it includes temperature and density effects by linearized Debye-Huckel and it treats excited configurations and H+He-like lines. Other is an average SHM using the parametric potentials above described. H-like emissivities and opacities have been simulated, using both, for Al and F plasmas with density 1023 cm-3 and temperatures higher than 200 eV. Advanced fusion cycles, as the aneutronic proton-boron 11 reaction, require very high ignition temperatures. Plasma conditions for a fusion-burning wave to propagate at such temperatures are rather extreme and complex, because of the overlapping effects of the main energy transport mechanisms. Calculations on the most appropriate ICF regimes for this purpose are presented. A new Monte Carlo procedure estimates effect of activation cross section uncertainties in the accuracy of inventory calculations, based on simultaneous random sampling of all the cross sections; it is implemented in activation code ACAB. We apply, with LLNL, to NIF gunite chamber shielding with reference pulsing operation. Preliminary results show that the 95 percentile of the distribution of the relative error of the contact dose rate can take values up to 1.2. Model is promising for uncertainty analysis of pulsed activation in IFE PP by using a continuous-pulsed model. Neutron intensities versus time after target emission are presented for IFE protections: LiPb/Flibe, including spectral effects. HT evaluation indicates that 90-98% of the total dose comes from ingestion of agriculture and meat, and the rest from inhalation by re-emission. A multiscale modeling (MM) study of pulse irradiation in Fe is presented up to microscopy; we give differences with continuous irradiation. Experimental validation of MM, using Fe+ in Fe, is being performed under VENUS II Spanish project with CIEMAT. Multiscale Modeling of SiC is reported; new defects energetic emerge using a new tight-binding molecular dynamics which has been proved in basic crystal parameters.

Velarde, G.; Perlado, J. M.; Alonso, M.; Bravo, E.; Cabellos, O.; Dominguez, E.; Eliezer, S.; Falquina, R.; Rubiano, J. G.; Gil, J. M.; del Rio, J. G.; Gonzalez, A. I.; Leon, P. T.; Lodi, D.; Marian, J.; Martel, P.; Martinez-Val, J. M.; Minguez, E.; Ogando, F.; Piera, M.; Prieto, J.; Relano, A.; Reyes, S.; Rodriguez, A.; Rodriguez, R.; Salvador, M.; Sanz, Jose L.; Senz, D. G.; Sauvan, P.; Velarde, M.; Velarde, P.

2003-12-01

2

Comments on experimental results of energy confinement of tokamak plasmas  

SciTech Connect

The results of energy-confinement experiments on steady-state tokamak plasmas are examined. For plasmas with auxiliary heating, an analysis based on the heat diffusion equation is used to define heat confinement time (the incremental energy confinement time). For ohmically sustained plasmas, experiments show that the onset of the saturation regime of energy confinement, marfeing, detachment, and disruption are marked by distinct values of the parameter /bar n//sub e///bar j/. The confinement results of the two types of experiments can be described by a single surface in 3-dimensional space spanned by the plasma energy, the heating power, and the plasma density: the incremental energy confinement time /tau//sub inc/ = ..delta..W/..delta..P is the correct concept for describing results of heat confinement in a heating experiment; the commonly used energy confinement time defined by /tau//sub E/ = W/P is not. A further examination shows that the change of edge parameters, as characterized by the change of the effective collision frequency ..nu../sub e/*, governs the change of confinement properties. The totality of the results of tokamak experiments on energy confinement appears to support a hypothesis that energy transport is determined by the preservation of the pressure gradient scale length. 70 refs., 6 figs., 1 tab.

Chu, T.K.

1989-04-01

3

Recent theoretical and experimental results on inertial fusion energy physics  

Microsoft Academic Search

We study with ARWEN code a target design for ICF based on jet production. ARWEN is 2D Adaptive Mesh Refinement fluid dynamic and multigroup radiation transport. We are designing, by using also ARWEN, a target for laboratory simulation of astrophysical phenomena. We feature an experimental device to reproduce collisions of two shock waves, scaled to roughly represent cosmic supernova remnants.

G. Velarde; J. M. Perlado; M. Alonso; E. Bravo; O. Cabellos; E. Dominguez; S. Eliezer; R. Falquina; J. G. Rubiano; J. M. Gil; J. G. del Rio; A. I. Gonzalez; P. T. Leon; D. Lodi; J. Marian; P. Martel; J. M. Martinez-Val; E. Minguez; F. Ogando; M. Piera; J. Prieto; A. Relano; S. Reyes; A. Rodriguez; R. Rodriguez; M. Salvador; Jose L. Sanz; D. G. Senz; P. Sauvan; M. Velarde; P. Velarde

2003-01-01

4

High energy imploding liner experiment HEL-1: Experimental results  

SciTech Connect

Magnetically driven imploding liner systems can be used as a source of shock energy for materials equation of state studies, implosion driven magnetized plasma fusion experiments, and other similar applications. The imploding liner is a cylinder of conducting material through which a current is passed in the longitudinal direction. Interaction of the current with its own magnetic field causes the liner to implode. Sources of electrical energy for imploding liner systems are capacitor banks or explosive pulse power systems seeded by capacitor banks. In August, 1996, a high energy liner experiment (HEL-1) was conducted at the All-Russia Scientific Research Institute (VNIIEF) in Sarov, Russia. A 5 tier 1 meter diameter explosive disk generator provided electrical energy to drive a 48 cm outside diameter, 4 mm thick, aluminum alloy liner having a mass of about 11kg onto an 11 cm diameter diagnostic package. The purpose of the experiment was to measure performance of the explosive pulse power generator and the heavy imploding liner. Electrical performance diagnostics included inductive (B-dot) probes, Faraday Rotation current measurement, Rogowski total current measurement, and voltage probes. Flux loss and conductor motion diagnostics included current-joint voltage measurements and motion sensing contact pins. Optical and electrical impact pins, inductive (B-dot) probes, manganin pressure probes, and continuously recording resistance probes in the Central Measuring Unit (CMU) and Piezo and manganin pressure probes, optical beam breakers, and inductive probes located in the glide planes were used as liner symmetry and velocity diagnostics. Preliminary analysis of the data indicate that a peak current of more than 100 MA was attained and the liner velocity was between 6.7 km/sec and 7.5 km/sec. Liner kinetic energy was between 22 MJ and 35 MJ. 4 refs., 6 figs., 1 tab.

Clark, D.A.; Anderson, B.G.; Ekdahl, C.A. [and others

1997-09-01

5

Thermal energy storage in a confined aquifer: Experimental results  

Microsoft Academic Search

To aid in testing the idea of storing thermal energy in aquifers, an experiment was performed by Auburn University in which 54,784 m3 of water was pumped from a shallow supply aquifer, heated to an average temperature of 55°C, and injected into a deeper confined aquifer where the ambient temperature was 20°C. After a storage period of 51 days, 55,345

F. J. Molz; A. D. Parr; P. F. Andersen; V. D. Lucido; J. C. Warman

1979-01-01

6

Experimental results from a second-order focusing toroidal energy spectrometer attachment for scanning electron microscopes  

Microsoft Academic Search

This paper presents experimental results from a second-order focusing toroidal spectrometer attachment for the scanning electron microscope (SEM). The energy resolution of the spectrometer is measured to be 0.38% for an angular spread of ±8°, close to the numerical simulated value of 0.32% based upon direct ray tracing. This result provides experimental confirmation of the superior focusing optics predicted for

H. Q. Hoang; M. Osterberg; A. Khursheed

2011-01-01

7

Modifications of the high-energy transport code (HETC) and comparisons with experimental results  

SciTech Connect

The High-Energy Transport Code HETC has been revised by incorporating a multi-chain fragmentation model to describe particle production from high-energy hadron-nucleus collisions. The revised code is briefly described and its validity is tested by comparing calculated results with experimental data from 29.4 GeV protons incident on an iron-air beam stop and with experimental data from 800 GeV protons incident on a large iron block. Some comparisons with calculated results obtained with other available transport codes; FLUKA82, CASIM, and MARS10 are also included. 18 refs., 3 figs.

Alsmiller, R.G. Jr.; Alsmiller, F.S.; Gabriel, T.A.; Hermann, O.W.

1987-01-01

8

Advanced energy-efficient house (HARBEMAN house) with solar thermal, photovoltaic, and sky radiation energies (experimental results)  

Microsoft Academic Search

An energy-independent residential house (‘HARBEMAN house’; Harmony BEtween Man And Nature), incorporating sky radiation cooling, solar thermal, and photovoltaic energies was built in Sendai, Japan during July, 1996. This paper reports monitored results of this house since September 1996 to date. The paper also presents simulation results for the HARBEMAN house and its results compared with the annual experimental data.

Takeo S. Saitoh; Tetsuji Fujino

2001-01-01

9

Application of broadband nonlinear targeted energy transfers for seismic mitigation of a shear frame: Experimental results  

NASA Astrophysics Data System (ADS)

In an earlier work we showed computationally that it is possible to successfully employ nonlinear targeted energy transfers (TETs) for seismic mitigation. Moreover, we demonstrated that this passive strategy of seismic vibration control was feasible and robust. In this work, we report experimental validation of these results by performing a series of experimental tests with a three-story shear-frame structure under seismic excitation in the form of two different historic earthquakes. As in the computational part of this work, the experimental seismic mitigation design consists of either a single nonlinear energy sink or a combination of two nonlinear energy sinks (NESs) attached at floors of the test structure. We study the performance and efficiency of the NES(s) through a set of certain evaluation criteria. With a single vibro-impact NES (VI NES) applied to the top floor of the test structure, we find significant reduction of the response levels. To further improve the effectiveness of the seismic mitigation design, we consider a combination of two NESs—an NES with smooth stiffness nonlinearity at the top floor and a VI NES at the bottom floor of the test structure—and show dramatic reduction of the structural seismic response. Robustness of the proposed designs is addressed.

Nucera, F.; Lo Iacono, F.; McFarland, D. M.; Bergman, L. A.; Vakakis, A. F.

2008-06-01

10

Experimental Estimation Of Energy Damping During Free Rocking Of Unreinforced Masonry Walls. First Results  

SciTech Connect

This paper presents an ongoing experimental program on unreinforced masonry walls undergoing free rocking. Aim of the laboratory campaign is the estimation of kinetic energy damping exhibited by walls released with non-zero initial conditions of motion. Such energy damping is necessary for dynamic modelling of unreinforced masonry local mechanisms. After a brief review of the literature on this topic, the main features of the laboratory tests are presented. The program involves the experimental investigation of several parameters: 1) unit material (brick or tuff), 2) wall aspect ratio (ranging between 14.5 and 7.1), 3) restraint condition (two-sided or one-sided rocking), and 4) depth of the contact surface between facade and transverse walls (one-sided rocking only). All walls are single wythe and the mortar is pozzuolanic. The campaign is still in progress. However, it is possible to present the results on most of the mechanical properties of mortar and bricks. Moreover, a few time histories are reported, already indicating the need to correct some of the assumptions frequent in the literature.

Sorrentino, Luigi; Masiani, Renato; Benedetti, Stefano [Dipartimento di Ingegneria Strutturale e Geotecnica, Sapienza Universita di Roma, via Antonio Gramsci, 53-00197 Roma (Italy)

2008-07-08

11

Controlling the electron energy distribution function of electron beam generated plasmas with molecular gas concentration: I. Experimental results  

NASA Astrophysics Data System (ADS)

This paper, the first in a series of two, presents experimental results demonstrating the control of electron and ion energy distribution functions in electron beam generated processing plasmas by adding trace concentrations of N2 to an Ar background. Measurements of the electron energy distribution function, f0(E), are performed using a Langmuir probe while measurements of the Ar ion energy distribution function are performed using an energy-resolved mass spectrometer. The experimental results agree with modeling results, described in part II of this work, which indicate that inelastic electron collisions with nitrogen molecules provide an energy sink that can be exploited to control the electron energy distribution function.

Boris, D. R.; Petrov, G. M.; Lock, E. H.; Petrova, Tz B.; Fernsler, R. F.; Walton, S. G.

2013-12-01

12

Augmented solar energy collection using different types of planar reflective surfaces - Theoretical calculations and experimental results  

Microsoft Academic Search

The paper reports theoretical and experimental studies of the use of different types of flat reflective surfaces to increase the collection of solar energy by flat collectors. Specular, diffuse, and combination specular\\/diffuse reflective surfaces are discussed. The reflectivity properties of a given surface are measured as a function of incident and reflected angles, and on the basis of these measurements

D. P. Grimmer; K. G. Zinn; K. C. Herr; B. E. Wood

1978-01-01

13

Review of direct energy conversion of ion beams: Experimental results and reactor applications  

Microsoft Academic Search

In order to produce neutral beams for fusion reactors efficiently, the energy carried by the unneutralized portion of the ion beam may have to be recovered in a direct converter. Several concepts applicable to beam direct conversion are discussed. The concept that has received the most attention uses planar sets of grids. One experimental test with a hydrogen ion beam

R. W. Moir

1974-01-01

14

Multigan®: First experimental results  

NASA Astrophysics Data System (ADS)

A new design of a multicharged ion source based on the MONO1000 ECRIS has been presented at the last ECR ion source (ECRIS) Workshop 2010. [L. Maunoury et al., in Proceedings of the XIXth International Workshop on ECR Ion Sources, Grenoble, France, 23-26 August 2010] This source has not only two opening at both ends but also a large space in the middle of the source enabling a direct contact with the ECR plasma. The source has been assembled mechanically and put on a test bench at the Pantechnik company. The primary tests have shown that the plasma ignition occurred at low pressure (10-6 mbar) and low RF power (10 W). The first experimental results ( = 1.30 for Ar and 1.85 for Xe) demonstrated the potential of this ion source in production of multicharged ion beams.

Maunoury, L.; Pacquet, J. Y.; Baret, P.; Donzel, X.; Dubois, M.; Gaubert, G.; Lehérissier, P.; Leroy, R.; Michel, M.; Villarit, A. C. C.

2012-02-01

15

Multigan: First experimental results  

SciTech Connect

A new design of a multicharged ion source based on the MONO1000 ECRIS has been presented at the last ECR ion source (ECRIS) Workshop 2010. [L. Maunoury et al., in Proceedings of the XIXth International Workshop on ECR Ion Sources, Grenoble, France, 23-26 August 2010] This source has not only two opening at both ends but also a large space in the middle of the source enabling a direct contact with the ECR plasma. The source has been assembled mechanically and put on a test bench at the Pantechnik company. The primary tests have shown that the plasma ignition occurred at low pressure (10{sup -6} mbar) and low RF power (10 W). The first experimental results (= 1.30 for Ar and 1.85 for Xe) demonstrated the potential of this ion source in production of multicharged ion beams.

Maunoury, L.; Pacquet, J. Y.; Baret, P.; Dubois, M.; Leherissier, P.; Michel, M. [GANIL, bd H. Becquerel BP 55027, F-14076 Caen cedex 05 (France); Donzel, X.; Gaubert, G.; Leroy, R.; Villarit, A. C. C. [PANTECHNIK, 13 rue de la resistance, F-14400 Bayeux (France)

2012-02-15

16

Experimental diagenesis: Exploratory results  

NASA Astrophysics Data System (ADS)

We conducted experiments in which a granular mixture of quartz and labradorite was deformed in compression at elevated temperatures (200-350 C) and pressures (100 MPa) in the presence of deionized water. Following initial consolidation of the material by application of the loads at room temperature, a second, hydrothermal phase of consolidation was observed when the temperature was increased with the loads fixed. The strain rate during this hydrothermal consolidation decayed approximately exponentially with time and was accompanied by only minor porosity reduction. The sample permeability decreased rapidly during the hydrothermal consolidation and continued to decrease following cessation of the deformation. The rate of this self-sealing process was a complex function of temperature. Scanning electron microscopy and microprobe analysis of the indurated post-experimental material showed albitization of the feldspar, especially in highly deformed regions. Analysis of post-experimental fluids show that Si in solution increased with increasing flow and temperature. Fluid-rock equilibrium was not achieved within the short durations of the experiments (50-60 hours). Our interpretation is that deformation occurred by grain boundary sliding aided by solution and reaction at high stress contacts, and sealing occurred by precipitation in low stress regions in the throats of pores.

Scholz, Christopher H.; Leger, Albert; Karner, Stephen L.

1995-03-01

17

Experimental and computational results on direct energy conversion for mirror fusion reactors  

Microsoft Academic Search

Results are presented for measurements of space-charge effects on the efficiency of a direct converter. The device consists of a 22-stage electrostatic periodic-focusing direct energy converter, a magnetic expander, and a hydrogen plasma source. At low beam density, the measured average efficiency is 86.5% + or - 1.5% as compared with the predicted one of 88.6% + or - 1.5%.

W. L. Barr; R. W. Moir; J. D. Kinney

1977-01-01

18

NLCTA injector experimental results  

SciTech Connect

The purpose of the Next Linear Collider Test Accelerator (NLCTA) at SLAC is to integrate the new technologies of X-band accelerator structures and RF systems for the Next Linear Collider (NLC), demonstrate multibunch beam-loading energy compensation and suppression of high-order deflecting modes, measure the transverse components of the accelerating field, and measure the dark current generated by RF field emission in the accelerator. For beam loading R and D, an average current of about 1 A in a 120 ns long bunch train is required. The initial commissioning of the NLCTA injector, as well as the rest of the accelerator have been progressing very well. The initial beam parameters are very close to the requirement and they expect that injector will meet the specified requirements by the end of this summer.

Yeremian, A.D.; Adolphsen, C.; Miller, R.H.; Nantista, C.D.; Wang, J.W.

1997-04-01

19

Experimental Results of a Nonconventional Energy Conversion Pilot Facility-Thermogravimetric System.  

National Technical Information Service (NTIS)

The experimental analysis of a freon-water two-phase thermogravimetric pilot plant is presented. A comparison with mathematical models, developed for the determination of the geometric characteristics, component sizing, and off design performances of the ...

S. Arosio M. Balestri F. Bonfanti G. Sotgia

1981-01-01

20

Resonances and Threshold Phenomena in Low-Energy Electron Collisions with Hydrogen Halides: New Experimental and Theoretical Results  

NASA Astrophysics Data System (ADS)

Low-energy electron collisions with HCl and HBr and the deuterated compounds have been investigated by experimental and theoretical methods. New experimental results have been obtained on relative differential cross-sections for vibrational excitation and dissociative electron attachment. Measurements with high energy resolution for rotationally cooled molecules have revealed, in addition to shape resonance, threshold peaks and Wigner cusps, the existence of surprisingly sharp oscillatory structures in the elastic and v = 0 1 vibrational excitation cross-sections in a narrow range below the dissociative attachment threshold. The theoretical analysis is based on an improved nonlocal resonance model which has been constructed on the basis of ab initio fixed-nuclei scattering phase shifts for HCl and HBr and accurate ab initio calculations of the bound part of the HCl- and HBr- potential-energy functions. The high degree of agreement which has been obtained between experiment and theory for all channels indicates that the mechanisms responsible for the rich threshold structures in the collision cross-sections are completely understood.

?ížek, M.; Horá?ek, J.; Allan, M.; Domcke, W.

2002-09-01

21

Theoretical analysis and experimental results on super-conducting magnetic energy storage (SMES) in dynamic simulation test of power system  

Microsoft Academic Search

This paper introduces a double-DSPs controlled power conditioning system (PCS) for superconducting magnetic energy storage (SMES), which is used for experimental study in dynamic simulation tests of power system. Considering of realization, voltage source converter (VSC) with a chopper is adopted in the experimental sample. The VSC in the PCS is a four-quadrant AC\\/DC converter and chopper is a two-quadrant

Hui Zhang; Yong Kang; Pengcheng Zhu; Xuejuan kong; Ping Liu; Jian Chen

2001-01-01

22

CDF experimental results on diffraction  

SciTech Connect

Experimental results on diffraction from the Fermilab Tevatron collider obtained by the CDF experiment are reviewed and compared. We report on the diffractive structure function obtained from dijet production in the range 0 < Q{sup 2} < 10,000 GeV{sup 2}, and on the |t| distribution in the region 0 < |t| < 1 GeV{sup 2} for both soft and hard diffractive events up to Q{sup 2} {approx} 4,500 GeV{sup 2}. Results on single diffractive W/Z production, forward jets, and central exclusive production of both dijets and diphotons are also presented.

Gallinaro, Michele; /Rockefeller U.

2009-04-01

23

Experimental Results in DIS from Jefferson Laboratory  

SciTech Connect

We are summarizing the experimental program of Jefferson Lab (Thomas Jefferson National Accelerator Facility in Newport News, VA) in deep inelastic electron scattering. We show recent results and discuss future plans for both the present 6 GeV era and the 12 GeV energy-upgraded facility.

Sebastian Kuhn

2009-10-01

24

TMX-U experimental results  

SciTech Connect

This paper describes results from the Tandem Mirror Experiment-Upgrade (TMX-U). Mirror-confined electrons with 30 to 70 keV mean energy densities of 0.5 to 2.0 x 10/sup 12/ cm/sup -3/ and average betas of 3 to 5% are produced using electron-cyclotron resonant heating (ECRH). These results are consistent with an electron Fokker-Planck code. Improved ion-cyclotron microstability is observed using neutral beam injection at 47/sup 0/ to the magnetic axis, rather than at 90/sup 0/ as in the previous experiment, TMX. Strong end plugging has been produced using a combination of ECRH gyrotrons with sloshing-ion beam injection. In these low-density central cell experiments (3 x 10/sup 11/ cm/sup -3/) the axial losses (tau/sub parallel/ = 20 to 80 ms) are smaller than the nonambipolar radial losses (tau/sub perpendicular/ = 4 to 8 ms). Plugging has been achieved with a central cell density double that of the end plugs. Although no direct measurements are yet available to determine if a thermal barrier potential dip is generated, these experiments support many theoretical features of the thermal barrier concept.

Simonen, T.C.; Allen, S.L.; Casper, T.A.; Clauser, J.F.; Clower, C.A.; Coensgen, F.H.; Correll, D.L.; Cummins, W.F.; Damm, C.C.; Failor, B.H.

1983-08-31

25

Study of the drift energies in the kronian magnetosphere: a comparison between model results and experimental data  

NASA Astrophysics Data System (ADS)

In the inner magnetosphere, the low energy particles (ions and electrons) corotate. Due to the gradient and the curvature of the field lines, the magnetic field influences the motion of the particles. Gradient and curvature are responsible of the existence of drift velocities perpendicular to the magnetic field lines. Above a critical energy, the total drift velocity will be higher than the corotation velocity. The electrons and the ions then rotate in opposite directions. We have developed a model which calculates the drift and corotation velocities, and apply it to determine the minimum energy. In this paper, we use data from the Cassini CAPS and MIMI instruments to compare the observed particle energy spectra with model result in order to explain the behaviour of the particles.

Grimald, S.; Arridge, C. S.; Rochel, A.; Dandouras, I.

2009-04-01

26

New experimental results at HERA.  

National Technical Information Service (NTIS)

Recent measurements by the ZEUS and H1 collaborations of the hadronic final state in deep inelastic scattering at HERA are reviewed. QCD is studied by means of charged particle spectra, jet rates and inclusive energy flows. (orig.) (ERA citation 20:014269...

M. Kuhlen

1994-01-01

27

Review of experimental results from SND detector  

Microsoft Academic Search

The review of experimental results obtained with SND detector at VEPP-2M\\u000a$e^+e^-$ collider in the energy region $\\\\sqrt[]{s}=0.36$ -- 1.38 GeV is given.\\u000aThe presented results include the following items: studies of the light vector\\u000amesons radiative decays, OZI-rule and G-parity suppressed $\\\\phi$-meson rare\\u000adecays, $\\\\phi$-meson parameters measurements, studies of\\u000a$e^+e^-\\\\to\\\\pi^+\\\\pi^-\\\\pi^0$ process dynamics, $\\\\eta$ and $K_S$ mesons rare\\u000adecays, $\\\\eta$

M. Aulchenko; V. M. Aulchenko; K. I. Beloborodov; A. G. Bogdanchikov; A. V. Bozhenok; A. D. Bukin; D. A. Bukin; S. V. Burdin; T. V. Dimova; A. A. Drozdetski; V. P. Druzhinin; D. I. Ganushin; V. B. Golubev; V. N. Ivanchenko; P. M. Ivanov; A. A. Korol; S. V. Koshuba; I. N. Nesterenko; E. V. Pakhtusova; A. A. Polunin; A. A. Salnikov; S. I. Serednyakov; V. A. Sidorov; Yu. M. Shatunov; Z. K. Silagadze; A. N. Skrinsky; A. G. Skripkin; Yu. V. Usov; A. V. Vasiljev

2001-01-01

28

Pentaquarks: the latest experimental results  

SciTech Connect

After the claim of the possible discovery of a pentaquark state, many experiments reported positive and negative results opening a discussion about the pentaquark existence. New experiments with high resolution and high statistics are needed in the reaction channels and for the kinematics of the positive results to solve the controversy. Jefferson Lab started a comprehensive program to search for pentaquark in photoproduction at threshold on proton and deuteron targets, collecting more than 10 times the existing statistics. The first experiment on the proton (g11) just finished to analyze the data, and the first results of the pentaquark search are reported here.

M. Battaglieri; R. De Vita; Valery Kubarovsky

2006-01-01

29

Wavefront control testbed experimental results  

NASA Astrophysics Data System (ADS)

The Wavefront Control Testbed (WCT) was created to develop and test wavefront sensing and control algorithms and software for the segmented James Webb Space Telescope (JWST). Last year, we changed the system configuration from three sparse aperture segments to a filled aperture with three pie shaped segments. With this upgrade we have performed experiments on fine phasing with line-of-sight and segment-to-segment jitter, dispersed fringe visibility and grism angle; high dynamic range tilt sensing; coarse phasing with large aberrations, and sampled sub-aperture testing. This paper reviews the results of these experiments.

Burns, Laura A.; Basinger, Scott A.; Campion, Scott D.; Faust, Jessica A.; Feinberg, Lee D.; Green, Joseph J.; Hayden, William L.; Lowman, Andrew E.; Ohara, Catherine M.; Petrone, Peter P., III; Redding, David C.; Shi, Fang; Van Buren, David; Zukowski, Barbara

2004-10-01

30

Recent Experimental Results from HELIOS  

NASA Astrophysics Data System (ADS)

The renewed emphasis on nuclear structure far from stability, studied with nucleon-transfer reactions that utilize radioactive beams, has led to many new and exciting results. Accompanying these developments are, however many technical challenges that confront studies of transfer reactions in inverse kinematics. Amongst these are the identification of reaction products and the resolution of states in the residual nuclei. A new device, HELIOS (the HELIcal Orbit Spectrometer) has been constructed to solve many of the problems encountered with such reactions. The device uses a uniform magnetic field produced by a large, superconducting solenoid to transport light reaction products from the target to a linear array of position-sensitive silicon detectors. In operation since August of 2008, HELIOS has been used to study a variety of (d,p) reactions with beams of stable and unstable ions with masses ranging from A=11 to 136.

Wuosmaa, A. H.

2013-03-01

31

Comparison of Model and Experimental Results for Material and Energy Flow in a Titanium Evaporation System with Deforming Interfaces.  

National Technical Information Service (NTIS)

Finite element calculations and measurements are compared for material and energy flow in a system to evaporate pure titanium. A 40 kW electron beam is used to heat the end of a 7.62 cm diameter cylindrical rod which is fed vertically through a water-cool...

M. A. McClelland K. W. Westerberg T. C. Meier D. G. Braun K. D. Frischknecht

2003-01-01

32

Cleanroom energy benchmarking results  

SciTech Connect

A utility market transformation project studied energy use and identified energy efficiency opportunities in cleanroom HVAC design and operation for fourteen cleanrooms. This paper presents the results of this work and relevant observations. Cleanroom owners and operators know that cleanrooms are energy intensive but have little information to compare their cleanroom's performance over time, or to others. Direct comparison of energy performance by traditional means, such as watts/ft{sup 2}, is not a good indicator with the wide range of industrial processes and cleanliness levels occurring in cleanrooms. In this project, metrics allow direct comparison of the efficiency of HVAC systems and components. Energy and flow measurements were taken to determine actual HVAC system energy efficiency. The results confirm a wide variation in operating efficiency and they identify other non-energy operating problems. Improvement opportunities were identified at each of the benchmarked facilities. Analysis of the best performing systems and components is summarized, as are areas for additional investigation.

Tschudi, William; Xu, Tengfang

2001-09-01

33

Experimental results of synthetic aperture microwave radiometer  

Microsoft Academic Search

Introduces briefly the principles of the interferometric synthetic aperture, a system design of a C-band microwave interferometric synthetic aperture radiometer and its experimental results. This system has a 6-element thinned array with 11 analog complex correlators to obtain the 11 visibility functions, which result in 22 digitally synthesized spatial resolution cells. The synthetic aperture radiometer has a spatial resolution as

Zhang Shengwei; Ji Wu; Jing Li; Shifeng Zheng; Jingshan Jiang

2002-01-01

34

Bioreactor landfills: experimental and field results  

Microsoft Academic Search

Bioreactor landfills allow a more active landfill management that recognizes the biological, chemical and physical processes involved in a landfill environment. This paper presents the results of an experimental study carried out to determine the effect of solid waste size, leachate recirculation and nutrient balance on the rate of municipal solid waste (MSW) biodegradation. Higher rates of MSW biodegradation eventually

Mostafa Warith

2002-01-01

35

PDX experimental results in FY82  

SciTech Connect

This report presents a detailed summary of the major experimental results of PDX in FY82 and represents the efforts of the entire PDX group. Topics covered include ..beta..-scaling and fishbone studies, fluctuations, disruptions, impurities and impurity transport, power handling, limiter conditioning, edge studies, plasma fueling, counter-injection, and diagnostic development. A less detailed version will appear as the FY82 PDX contribution to the PPPL Annual Report.

Kaye, S.M.; Bell, M.; Bol, K.; Bitter, M.; Buchenauer, D.; Budny, R.; Brau, K.; Crowley, T.; Davis, S.; Dylla, H.

1983-08-01

36

Tokamak scaling laws, with special emphasis on TFR experimental results  

NASA Astrophysics Data System (ADS)

Scaling laws mainly based on TFR experimental results are derived and compared with data obtained on other tokamaks. Scaling laws for gross energy confinement time, critical electron density, electron and ion temperatures, and critical plasma pressure are considered. In addition, a short discussion of the particle confinement time is given. The derived scaling law is used to predict the INTOR performance.

1980-10-01

37

EXPERIMENTAL RESULTS ON CHARGE-CHANGING COLLISIONS OF HYDROGEN AND HELIUM ATOMS AND IONS AT KINETIC ENERGIES ABOVE 0.2 kev  

Microsoft Academic Search

Experimental results on charge-changing collisions of hydrogen and ; helinum are reviewed. Theoretical attempts to compute the charge-changing cross ; sections are not discussed, but a list of theoretical papers is given as a ; separate bibliography. (W.D.M.);

Samuel Allison

1958-01-01

38

Overview of the initial NSTX experimental results  

SciTech Connect

The main aim of the National Spherical Torus Experiment (NSTX) is to establish the fusion physics principles of the spherical torus (ST) concept. The NSTX device began plasma operations in February 1999 and the plasma current Ip was successfully brought up to the design value of 1 MA on 14 December 1999. The planned plasma shaping parameters, elongation = 1:6{2.2 and triangularity = 0:2{0.4, were achieved in inner wall limited, and single null and double null diverted congurations. The coaxial helicity injection (CHI) and high harmonic fast wave (HHFW) experiments were also initiated. CHI current of 27 kA produced up to 260 kA toroidal current without using an ohmic solenoid. With the injection of 2.3 MW of HHFW power, using 12 antennas connected to six transmitters, electrons were heated from a central temperature of 400 eV to 900 eV at a central density of 3:5 1013 cm 3, increasing the plasma energy to 59 kJ and the toroidal , T , to 10%. The NBI system commenced operation in September 2000. The initial results with two ion sources (PNBI = 2:8 MW) show good heating, producing a total plasma stored energy of 90 kJ corresponding to T 18% at a plasma current of 1.1 MA.

Ono, M. [Princeton Plasma Physics Laboratory (PPPL); Peng, Yueng Kay Martin [ORNL

2000-01-01

39

Overview of the initial NSTX experimental results  

NASA Astrophysics Data System (ADS)

The main aim of the National Spherical Torus Experiment (NSTX) is to establish the fusion physics principles of the spherical torus (ST) concept. The NSTX device began plasma operations in February 1999 and the plasma current Ip was successfully brought up to the design value of 1 MA on 14 December 1999. The planned plasma shaping parameters, elongation ? = 1.6-2.2 and triangularity ? = 0.2-0.4, were achieved in inner wall limited, and single null and double null diverted configurations. The coaxial helicity injection (CHI) and high harmonic fast wave (HHFW) experiments were also initiated. CHI current of 27 kA produced up to 260 kA toroidal current without using an ohmic solenoid. With the injection of 2.3 MW of HHFW power, using 12 antennas connected to six transmitters, electrons were heated from a central temperature of 400 eV to 900 eV at a central density of 3.5 × 1013 cm-3, increasing the plasma energy to 59 kJ and the toroidal ?, ?T, to 10%. The NBI system commenced operation in September 2000. The initial results with two ion sources (PNBI = 2.8 MW) show good heating, producing a total plasma stored energy of 90 kJ corresponding to ?T approx 18% at a plasma current of 1.1 MA.

Ono, M.; Bell, M. G.; Bell, R. E.; Bigelow, T.; Bitter, M.; Blanchard, W.; Darrow, D. S.; Fredrickson, E. D.; Gates, D. A.; Grisham, L. R.; Hosea, J. C.; Johnson, D. W.; Kaita, R.; Kaye, S. M.; Kubota, S.; Kugel, H. W.; LeBlanc, B. P.; Maingi, R.; Maqueda, R.; Mazzucato, E.; Menard, J.; Mueller, D.; Nelson, B. A.; Neumeyer, C.; Paoletti, F.; Paul, S. F.; Peng, Y.-K. M.; Ramakrishnan, S.; Raman, R.; Ryan, P. M.; Sabbagh, S. A.; Skinner, C. H.; Stevenson, T.; Stutman, D.; Swain, D. W.; Synakowski, E. J.; Taylor, G.; Von Halle, A.; Wilgen, J.; Williams, M.; Wilson, J. R.; Zweben, S. J.; Ackers, R.; Barry, R. E.; Bers, A.; Bialek, J. M.; Bonoli, P. T.; Carter, M. D.; Chrzanowski, J.; Davis, W.; Doyle, E. J.; Dudek, L.; Efthimion, P. C.; Ellis, R.; Ferron, J. R.; Finkenthal, M.; Fredd, E.; Gibney, T.; Goldston, R. J.; Hatcher, R. E.; Hawryluck, R. J.; Hayashiya, H.; Hill, K. W.; Jarboe, T. R.; Jardin, S. C.; Ji, H.; Kalish, M.; La Marche, P.; Lao, L. L.; Lee, K. C.; Levinton, F. M.; Luhmann, N. C.; Majeski, R.; Manickam, J.; Marsala, R.; Mau, T. K.; McCormack, B.; Medley, S. S.; Menon, M. M.; Mitarai, O.; Nagata, M.; Nishino, N.; Oliaro, G.; Park, H. K.; Parsells, R.; Pearson, G.; Peebles, T.; Phillips, C. K.; Pinsker, R.; Porter, G. D.; Ram, A. K.; Robinson, J.; Roney, P.; Roquemore, A. L.; Rosenberg, A.; Schaffer, M.; Shiraiwa, S.; Sichta, P.; Stotler, D.; Stratton, B. C.; Takase, Y.; Wampler, W. R.; Wurden, G. A.; Xu, X. Q.; Yang, J. G.; Zeng, L.; Zhu, W.

2001-10-01

40

Overview of the Initial NSTX Experimental Results  

SciTech Connect

The main aim of the National Spherical Torus Experiment (NSTX) is to establish the fusion physics principles of the spherical torus (ST) concept. The NSTX device began plasma operations in February 1999 and the plasma current Ip was successfully brought up to the design value of 1 million amperes on December 14, 1999. The planned plasma shaping parameters, k = 1.6 - 2.2 and d = 0.2 - 0.4, were achieved in inner limited, single null and double null configurations. The CHI (Coaxial Helicity Injection) and HHFW (High Harmonic Fast Wave) experiments were also initiated. A CHI injected current of 27 kA produced up to 260 kA of toroidal current without using an ohmic solenoid. With an injection of 2.3 MW of HHFW power, using twelve antennas connected to six transmitters, electrons were heated from a central temperature of 400 eV to 900 eV at a central density of 3.5 x 1013 cm-3 increasing the plasma energy to 59 kJ and the toroidal beta, bT to 10 %. Finally, the NBI system commenced operation in Sept. 2000. The initial results with two ion sources (PNBI = 2.8 MW) shows good heating, producing a total plasma stored energy of 90 kJ corresponding to bT 18 % at a plasm current of 1.1 MA.

Ono, M. [Princeton Plasma Physics Laboratory (PPPL); Bell, M. [Princeton Plasma Physics Laboratory (PPPL); Bell, R. E. [Princeton Plasma Physics Laboratory (PPPL); Bigelow, Tim S [ORNL; Bitter, M. [Princeton Plasma Physics Laboratory (PPPL); Blanchard, W. [Princeton Plasma Physics Laboratory (PPPL); Darrow, D. [Princeton Plasma Physics Laboratory (PPPL); Fredrickson, E. [Princeton Plasma Physics Laboratory (PPPL); Gates, D. [Princeton Plasma Physics Laboratory (PPPL); Grisham, L. [Princeton Plasma Physics Laboratory (PPPL); Hosea, J. [Princeton Plasma Physics Laboratory (PPPL); Kaye, S. [Princeton Plasma Physics Laboratory (PPPL); Kaita, R. [Princeton Plasma Physics Laboratory (PPPL); Kubota, S. [University of California, Los Angeles; Kugel, H. [Princeton Plasma Physics Laboratory (PPPL); Johnson, D. [Princeton Plasma Physics Laboratory (PPPL); LeBlanc, B [Princeton Plasma Physics Laboratory (PPPL); Maingi, Rajesh [ORNL; Maqueda, R. [Los Alamos National Laboratory (LANL); Mazzucato, E. [Princeton Plasma Physics Laboratory (PPPL); Menard, J. [Princeton Plasma Physics Laboratory (PPPL); Mueller, D. [Princeton Plasma Physics Laboratory (PPPL); Nelson, Brad E [ORNL; Neumeyer, C. L. [Princeton Plasma Physics Laboratory (PPPL); Paoletti, F. [Columbia University; Paul, S. [Princeton Plasma Physics Laboratory (PPPL); Peng, Yueng Kay Martin [ORNL; Ramakrishnan, S. [Princeton Plasma Physics Laboratory (PPPL); Raman, R. [University of Washington, Seattle; Ryan, Philip Michael [ORNL; Sabbagh, S. A. [Columbia University; Skinner, C. [Princeton Plasma Physics Laboratory (PPPL); Stevenson, T. [Princeton Plasma Physics Laboratory (PPPL); Stutman, D. [Johns Hopkins University; Synakowski, E. J. [Princeton Plasma Physics Laboratory (PPPL); Swain, David W [ORNL; Taylor, G. [Princeton Plasma Physics Laboratory (PPPL); Von Halle, A. [Princeton Plasma Physics Laboratory (PPPL); Wilgen, John B [ORNL; Williams, M. [Princeton Plasma Physics Laboratory (PPPL); Wilson, J. R. [Princeton Plasma Physics Laboratory (PPPL); Ackers, R. [EURATOM / UKAEA, UK; Barry, Robert E [ORNL; Bers, A. [Massachusetts Institute of Technology (MIT); Bialek, J. [Columbia University; Bonoli, P. [Massachusetts Institute of Technology (MIT); Carter, Mark Dwain [ORNL; Chrzanowski, J. [Princeton Plasma Physics Laboratory (PPPL); Davis, W. [Princeton Plasma Physics Laboratory (PPPL); Doyle, E. J. [University of California, Los Angeles; Dudek, L. [Princeton Plasma Physics Laboratory (PPPL); Ellis, R. [Princeton Plasma Physics Laboratory (PPPL); Efthimion, P. C. [Princeton Plasma Physics Laboratory (PPPL); Ferron, J. R. [General Atomics; Fredd, E. [Princeton Plasma Physics Laboratory (PPPL); Finkenthal, M. [Johns Hopkins University; Gibney, T. [Princeton Plasma Physics Laboratory (PPPL); Goldston, R. [Princeton Plasma Physics Laboratory (PPPL); Hatcher, R. E. [Princeton Plasma Physics Laboratory (PPPL); Hawryluck, R. [Princeton Plasma Physics Laboratory (PPPL); Hayashiya, H. [Fusion Physics and Technology; Hill, K. [Princeton Plasma Physics Laboratory (PPPL); Jarboe, T. [University of Washington, Seattle; Jardin, S. C. [Princeton Plasma Physics Laboratory (PPPL); Ji, H. [Princeton Plasma Physics Laboratory (PPPL); Kalish, M. [Princeton Plasma Physics Laboratory (PPPL); Lao, L. L. [General Atomics; Lee, K. C. [University of California, Davis; Levinton, F. [Fusion Physics and Technology; Luhmann, N. C. [University of California, Davis; Lamarche, P. [Princeton Plasma Physics Laboratory (PPPL); McCormack, B. [Princeton Plasma Physics Laboratory (PPPL); Majeski, R. [Princeton Plasma Physics Laboratory (PPPL); Manickam, J. [Princeton Plasma Physics Laboratory (PPPL); Marsala, R. [Princeton Plasma Physics Laboratory (PPPL); Mau, T. K. [University of California, San Diego; Medley, S. [Princeton Plasma Physics Laboratory (PPPL); et al.

2001-01-01

41

Prototype of dual energy x-ray tomodensimeter for lumbar spine bone mineral density measurement: choice of the reconstruction algorithm and first experimental results.  

PubMed

A dual-energy x-ray tomodensimeter adapted for the determination of bone mineral density (BMD) of the lumbar vertebrae has been directly developed from a typical dual-energy x-ray absorptiometer. This apparatus consists of two fundamental parts: a dual energy x-ray tube, and a multidetector made by an array of 24 NaI(T1) crystals. It provides both tomographic and non-tomographic (anteroposterior, lateral etc) measurement. The detection area is limited to 132 mm. In this condition, the choice of the best reconstruction algorithm in order to give a direct BDM is considered. Preliminary studies based on numerical simulated projections and hydroxyapatite phantoms demonstrated the superiority of algebraic reconstruction algorithms, such as conjugated gradient, in order to resolve the problems of (i) the impossibility of defining an internal calibration, and (ii) the potential for reconstruction errors due to the presence of bone structures located out of the detection area. The accuracy of BMD measurement is within 2%, with in vitro precision approximately 1%, and linearity characterized by a standard error of estimation (SEE) of 2 mg cm-3 in the range of lumbar BMD (less than 400 mg cm-3). Experimental data derived from two volunteers are presented. PMID:1470641

Kotzki, P O; Mariano-Goulart, D; Rossi, M

1992-12-01

42

Preliminary Experimental Results from a MARS Micro-CT System  

PubMed Central

The Medipix All Resolution System (MARS) system is a commercial spectral/multi-energy micro-CT scanner designed and assembled by the MARS Bioimaging, Ltd. in New Zealand. This system utilizes the state-of-the-art Medipix photon-counting, energy-discriminating detector technology developed by a collaboration based at European Organization for Nuclear Research (CERN). In this paper, we report our preliminary experimental results using this system, including geometrical alignment, photon energy characterization, protocol optimization, and spectral image reconstruction. We produced our scan datasets with a multi-material phantom, and then applied ordered subset-simultaneous algebraic reconstruction technique (OS-SART) to reconstruct images in different energy ranges and principal component analysis (PCA) to evaluate spectral deviation between the energy ranges.

He, Peng; Yu, Hengyong; Thayer, Patrick; Jin, Xin; Xu, Qiong; Bennett, James; Tappenden, Rachael; Wei, Biao; Goldstein, Aaron; Renaud, Peter; Butler, Anthony; Butler, Phillip; Wang, Ge

2013-01-01

43

Endovascular Electrocoagulation: Concept, Technique, and Experimental Results  

Microsoft Academic Search

PURPOSE: To evaluate the safety and efficacy of an embolotherapeutic technique that uses electrolytically detachable platinum coils and radio frequency (RF) energy to achieve rapid and distal occlusion of targeted vessels. METHODS: In swine, branches of the ascending cervical artery and the hepatic artery measuring 1.5 mm or less were subjected to endovascular electrocoagula- tion. RF energy was delivered through

Cheng Ji; Guido Guglielmi; Hank Chen

44

VALIDATION DATA FOR PHOTOCHEMICAL MECHANISMS: EXPERIMENTAL RESULTS  

EPA Science Inventory

The smog chamber facility of the University of North Carolina (UNC) was used to provide experimental data for the EPA and atmospheric model developers for testing and validating kinetic mechanisms of photochemical smog formation. In the study, 71 dual-experiments were performed u...

45

Model Comparisons with STELLA Experimental Results.  

National Technical Information Service (NTIS)

High-trapping efficiency and narrow energy spread in a staged laser acceleration system was demonstrated during the Staged Electron Laser Acceleration (STELLA) experiment. The experiment used inverse free electron lasers (IFEL) driven by the Brookhaven Na...

W. D. Kimura M. Babzien I. Ben-Zvi L. C. Campbell D. B. Cline C. E. Dilley J. C. Gallardo S. C. Gottschalk K. P. Kusche

2004-01-01

46

Deductive versus inductive equilibrium selection: experimental results  

Microsoft Academic Search

The debate in equilibrium selection appears to have culminated in the formation of two schools of thought: those who favor equilibrium selection based on rational coordination and those who favor zero-rationality adaptation. We examine four deductive selection principles and find that each fails to explain experimental data. We propose an inductive selection principle based on simple learning dynamics. Using out-of-sample

Ernan Haruvy; Dale O. Stahl

2004-01-01

47

Deductive versus inductive equilibrium selection: experimental results  

Microsoft Academic Search

The debate in equilibrium selection appears to have culminated in the formation of two schools of thought: those who favor equilibrium selection based on rational coordination and those who favor zero-rationality adaptation. We examine four deductive selection principles and find that each fails to explain experimental data. We propose an inductive selection principle based on simple learning dynamics. Using out-of-sample

Ernan Haruvy; Dale O. Stahl

2001-01-01

48

OMEGA experimental program and recent results  

SciTech Connect

The OMEGA laser system at the Laboratory for Laser Energetics is now a fully operational UV target irradiation facility with a program designed to address direct-drive laser fusion issues relevant to the U.S. National Ignition Facility presently under construction at Lawrence Livermore National Laboratory (LLNL). In addition, OMEGA is used to support the indirect-drive laser fusion program at LLNL and the Los Alamos National Laboratory. This paper describes the laser characteristics as well as some details of the experimental program that has been carried out over the past three years at this facility.

Seka, W.; Babushkin, A.; Boehly, T. R.; Bradley, D. K.; Cable, M. D.; Craxton, R. S.; Delettrez, J. A.; Donaldson, W. R.; Harding, D. R.; Jaanimagi, P. A.; Keck, R. L.; Kelly, J. H.; Kessler, T. J.; Knauer, J. P.; Kremens, R. L.; Marshall, F. J.; McCrory, R. L.; McKenty, P. W.; Meyerhofer, D. D.; Morse, S. F. B. [Laboratory for Laser Energetics, University of Rochester, 250 E. River Rd., Rochester, New York 14623 (United States)] (and others)

1997-04-15

49

CROSSBREEDING FOR BEEF PRODUCTION: EXPERIMENTAL RESULTS 1  

Microsoft Academic Search

Summary One approach to summarizing the research results from cattle crossbreeding studies is to consider the relative importance of breed differences, reciprocal differences and heterosis as they affect various characters. Breed effects as indicated by the maximum differences outlined in this review were of moderate to high magnitude for most of the characters considered. This result implies that selection among

Charles R. Long

2009-01-01

50

The Humanoid Robot LOLA-Experimental Results  

NASA Astrophysics Data System (ADS)

With the experience gathered during the development and construnction of the robot JOHNNIE, a new humanoid robot LOLA was built. Goal of this project is to realize a fast, human-like walking. Different aspects of this complex mechatronic system and the first experiments results are presented. The lightweight construction and the custom build multi-sensory joint drives with high torque brushless motors are introduced. The new decentralized electronic control/sensing network is also discuss as well as the simulation environment, the trajectory planning algorithm and the stabilizing walking control. Finally the first experiments result are presented.

Favot, V.; Schwienbacher, M.; Buschmann, T.; Lohmeier, S.; Ulbrich, H.

2010-09-01

51

Feedback control of a cupola - concepts and experimental results  

SciTech Connect

In this paper we present some final results from a research project focused on introducing automatic control to the operation of cupola iron furnaces. The main aim of this research is to improve the operational efficiency and performance of the cupola furnace, an important foundry process used to melt iron. Previous papers have described the development of appropriate control system architectures for the cupola. These results are summarized. Then we describe the experimental results obtained with the U.S. Department of Energy Albany Research Center`s research cupola. First, experimental data is used to calibrate the model, which is taken as a first-order multivariable system with time delay. Then relative gain analysis is used to select loop pairings to be used in a multi-loop controller. The resulting controller pairs meltrate with blast volume, iron temperature with oxygen addition, and carbon composition with percent coke. Special (nonlinear) filters are used to compute meltrate from actual scale readings of the amount of iron produced and to smooth the temperature measurement. The temperature and meltrate loops use single-loop PI control. The composition loop uses a Smith predictor to discount the deadtime associated with mass transport through the furnace. Experimental results validate the conceptual controller design and provide proof-of-concept of the idea of controlling a foundry cupola. Future research directions are discussed, including the concept of an integrated, intelligent industrial process controller, or I{sup 3}PC.

Moore, K.L. [Idaho State Univ., Pocatello, ID (United States); Abdelrahman, M.A. [Tenn. Technological Univ., Cookeville, TN (United States); Larsen, E.; Clark, D. [Lockheed Martin Idaho Technologies Co., Idaho Falls, ID (United States); King, P. [US Dept. of Energy Albany Research Center, Albany, OR (United States)

1998-10-01

52

Ventricular Fibrillation in Mammalian Hearts: Experimental Results  

NASA Astrophysics Data System (ADS)

Ventricular fibrillation (VF) is sustained by the continuous “breakup” of rapidly rotating spiral waves. The rate dependence of action potential duration (APD), i.e. APD restitution, plays a role in the induction and breakup of spiral waves. However, the role of conduction velocity (CV) and spatial heterogeneities, in VF induction and maintenance is not clear. We studied restitution, its spatial dispersion, and VF in small (rabbit) and large (pig) hearts using a video imaging system. We studied the effect of two drugs, diacetyl monoxime (DAM) and cytochalasinD (Cyto), in rabbit hearts. Control APDs were shorter than for Cyto but longer than for DAM. CV was greater for Cyto compared to DAM and APD dispersion increased with increasing rate for both drugs. VF was sustained in control, non-sustained with CytoD, and converted to a stable reentry (VT) with DAM. The slight increase of APD with Cyto increased the wavelength and probably prevented VF from being sustained. The DAM results can be explained by the reduction of wavelength and slope of the APD restitution curve. Except for VF, CytoD results were similar to controls. We performed similar studies in larger (pig) hearts with Cyto. APD and restitution slope at rapid rates were smaller for the pig compared to the rabbit. In the pig, APDs recorded during pacing induction protocols, VF and VT demonstrated that during periods of transition, APDs did not fall on the restitution curve. However, the deviations were predictable. During rapid pacing and VT/VF induction, APDs were longer than predicted from the restitution curve, while they were shorter for the conversions of VF to VT and their terminations. Overall, these studies are beginning to elucidate the dynamics and factors involved in the complex spatio-temporal patterns and their transitions that occur at rapid rates such as VT and VF.

Gray, Richard A.

2002-03-01

53

Experimental results from the TFTR tokamak  

SciTech Connect

Recent experiments on TFTR have extended the operating regime of TFTR in both ohmic- and neutral-beam-heated discharges. The TFTR tokamak has reached its original machine design specifications (I/sub p/ = 2.5 MA and B/sub T/ = 5.2 T). Initial neutral-beam-heating experiments used up to 6.3 MW of deuterium beams. With the recent installation of two additional beamlines, the power has been increased up to 11 MW. A deuterium pellet injector was used to increase the central density to 2.5 x 10/sup 20/ m/sup -3/ in high current discharges. At the opposite extreme, by operating at low plasma current (I/sub p/ approx. 0.8 MA) and low density (anti n/sub e/ approx. 1 x 10/sup 19/ m/sup -3/), high ion temperatures (9 +- 2 keV) and rotation speeds (7 x 10/sup 5/ m/s) have been achieved during injection. In addition, plasma compression experiments have demonstrated acceleration of beam ions from 82 keV to 150 keV, in accord with expectations. The wide operating range of TFTR, together with an extensive set of diagnostics and a flexible control system, has facilitated transport and scaling studies of both ohmic- and neutral-beam-heated discharges. The results of these confinement studies are presented.

Hawryluk, R.J.; Arunasalam, V.; Bell, J.D.; Bell, M.G.; Bitter, M.; Blanchard, W.R.; Bloody, F.; Bretz, N.; Budny, R.; Bush, C.E.

1986-10-01

54

Experimental results of bispectral invariants discriminative power  

NASA Astrophysics Data System (ADS)

One of the main tools in shape matching and pattern recognition are invariants. For three-dimensional data, rotation invariants comprise of two main kinds: moments and spherical harmonic magnitudes. Both are well examined and both suffer from certain limitations. In search for better performance, a new kind of spherical-harmonic invariants have been proposed recently, called bispectral invariants. They are well-established from theoretical point of view. They posses numerous beneficial properties and advantages over other invariants, include the ability to distinguish rotation from reflection, and the sensitivity to phase. However, insufficient research has been conducted to check their behavior in practice. In this paper, results are presented pertaining to the discriminative power of bispectral invariants. Objects from Princeton Shape Benchmark database are used for evaluation. It is shown that the bispectral invariants outperform power spectral invariants, but perform worse than other descriptors proposed in the literature such as SHELLS and SHD. The difference in performance is attributable to the implicit filtering used to compute the invariants.

Kubicki, Karol; Kakarala, Ramakrishna

2012-02-01

55

Constricting force of filamentary protein rings evaluated from experimental results  

NASA Astrophysics Data System (ADS)

We present a model of Z -ring constriction in bacteria based on different experimental in vitro results. The forces produced by the Z ring due to lateral attraction of its constituent parts, estimated in previous studies that were based on FtsZ filaments observed by atomic force microscopy, are in good agreement with an estimation of the force required for recently found deformations in liposomes caused by FtsZ. These forces are calculated within the usual Helfrich energy formalism. In this context, we also explain the apparent attraction of multiple Z rings in the liposomes initially separated by small distances, as well as the stable distribution of rings separated by distances greater than approximately twice the diameter of the cylindrical liposomes. We adapted the model to the in vivo conditions imposed by the bacterial cell wall, concluding that the proposed mechanism gives a qualitative explanation for the force generation during bacterial division.

Hörger, I.; Campelo, F.; Hernández-Machado, A.; Tarazona, P.

2010-03-01

56

Measurements of 2s 2S1/2-2p 2P1/2,3/2 transition energies in lithiumlike heavy ions. II. Experimental results for Ag44+ and discussion along the isoelectronic series  

NASA Astrophysics Data System (ADS)

Wavelengths of the fine structure transitions 2s 2S1/2-2p 2P3/2 and 2s 2S1/2-2p 2P1/2 in lithiumlike Ag44+ have been measured using beam-foil excitation and grazing incidence spectroscopy. The respective transition wavelengths of 40.829+/-0.004 Å and of 124.685+/-0.009 Å were not measured before for this ion. The achieved precision of 70 ppm for the 1/2-1/2 transition allows for a 0.2% QED test which sets a new benchmark in the medium Z range. Our experimental uncertainty is smaller than calculated two-photon exchange contributions to the transition energy. A summary of all published experimental data along the isoelectronic sequence for Z>=24, including our recent results for Ni25+ and Zn27+, is presented and compared with the best available calculations.

Bosselmann, Ph.; Staude, U.; Horn, D.; Schartner, K.-H.; Folkmann, F.; Livingston, A. E.; Mokler, P. H.

1999-03-01

57

Experimental Results of Hydrate Reservoir Destabilization Through Heating  

NASA Astrophysics Data System (ADS)

Gas clathrate reservoirs have been considered as possible sources of energy, as hazards to deep water drilling operations, and as contributors to global climate change. Clathrate destabilization may occur through depressurization of the reservoir, addition of chemical inhibitors, or heating the reservoir. Meso-scale heat conduction experiments were conducted in the Seafloor Process Simulator (SPS) at Oak Ridge National Laboratory in an attempt to apply experimental constraints to purely numerical models of heat transfer within a nearly isobaric reservoir. A column of saturated sediment was place inside the pressure vessel and pressurized to conditions sufficient to form methane clathrate at seafloor temperatures, while the system remained at room temperature (298K). Once pressurized, the temperature of the vessel was then lowered to approximately 275K, forming pore filling clathrate in the sediment column. Following hydrate formation, heat was supplied to the center of the clathrate reservoir through a hot fluid heat exchanger embedded in the sediment column to dissociate the methane hydrate. Relative changes in temperature within the hydrate-sediment column were monitored with a fiber optic quasi-distributed sensing system (DSS), along with temperature and pressure within the vessel headspace. Using the DSS Plotter analysis software, it was determined that an axis-symmetric section of clathrate was dissociated around the heat exchanger. Clathrate dissociation was accompanied by a small rise in vessel headspace pressure in addition to the expected thermal expansion of the headspace gas. The quantity of heat input to the system was calculated from the drop in fluid temperature as it flowed through the heat exchanger. Increased heat input resulted in an increase in the volume of hydrate dissociated. Clathrate rapidly reformed immediately upon the removal of the heat energy. A simple numerical model has been developed to simulate the heat flow in the system. Early results are promising and with further refinement the gap between the volume of hydrate dissociation predicted from the model and the experimental data observed on the LUNA DSS system will close. Much of the thermal energy is used to counter the heat of dissociation and heat input from the cold room the vessel is in. Some thermal energy was also lost in the pipelines inside the vessel.

Leeman, J.; Hornbach, M. J.; Elwood-Madden, M.; Phelps, T. J.; Rawn, C. J.

2011-12-01

58

Non-Shock Initiation Model for Explosive Families: Experimental Results  

NASA Astrophysics Data System (ADS)

The ``DaMaGe-Initiated-Reaction'' (DMGIR) computational model has been developed to predict the response of high explosives to non-shock mechanical insults. The distinguishing feature of this model is the introduction of a damage variable, which relates the evolution of damage to the initiation of a reaction in the explosive, and its growth to detonation. Specifically designed experiments were used to study the initiation process of each explosive family with embedded shock sensors and optical diagnostics. The experimental portion of this model development began with a study of PBXN-5 to develop DMGIR model coefficients for the rigid plastic bonded family, followed by studies of the cast, and bulk-moldable explosive families. The experimental results show an initiation mechanism that is related to input energy and material damage, with well defined initiation thresholds for each explosive family. These initiation details will extend the predictive capability of the DMGIR model from the rigid family into the cast and bulk-moldable families.

Anderson, M. U.; Todd, S. N.; Caipen, T. L.; Jensen, C. B.; Hughs, C. G.

2009-12-01

59

Experimental High Energy Neutrino Astrophysics  

SciTech Connect

Neutrinos are considered promising probes for high energy astrophysics. More than four decades after deep water Cerenkov technique was proposed to detect high energy neutrinos. Two detectors of this type are successfully taking data: BAIKAL and AMANDA. They have demonstrated the feasibility of the high energy neutrino detection and have set first constraints on TeV neutrino production astrophysical models. The quest for the construction of km3 size detectors have already started: in the South Pole, the IceCube neutrino telescope is under construction; the ANTARES, NEMO and NESTOR Collaborations are working towards the installation of a neutrino telescope in the Mediterranean Sea.

Distefano, Carla [Laboratori Nazionali del Sud, Catania (Italy)

2005-10-12

60

Photon Counting Chirped AM Ladar: Concept, Simulation, and Experimental Results.  

National Technical Information Service (NTIS)

The operating principles and experimental results for the Army Research Laboratory's (ARL's) patented chirped amplitude modulation (AM) ladar using linear response detectors have been presented and published previously, and will be briefly summarized here...

B. Redman M. Giza W. Ruff

2006-01-01

61

Energy non-linearity effects in the response of ionic crystal scintillators to X-rays with energy in the region of the K-absorptions edges: experimental results  

NASA Astrophysics Data System (ADS)

The response of a YAP, NaI(Tl) and BaF2 scintillators to X-rays with energies around the Y, I, and Ba K-absorption edges, respectively, was investigated. For all the scintillators, the amplitude response follows different linear trends for X-ray energies below and above the respective K-edges, presenting a discontinuity at these energies. An abrupt decrease of about 3%, 5% and 2% were observed in the detector amplitude at the K-edges, for the YAP, the NaI(Tl) and the BaF2 scintillator, respectively, corresponding to a decrease of 0.5+/-0.1, 1.7+/-0.3 and 0.8+/-0.2keV in the energy calibration line. These discontinuities result in a region within 0.5+/-0.1, 1.6+/-0.3 and 0.9+/-0.2keV where the X-ray energy cannot be obtained unambiguously. The scintillation yields for X-rays present abrupt decreases of about 3%, 4% and 2%, respectively, at the K-edges. The measured non-linearity effects are significantly larger than those obtained for gaseous and semiconductor detectors. The higher amplitude non-linearity observed in NaI(Tl) is attributed to the larger light yield non-linearity in the electron response of this crystal.

Ferreira, L. F. Requicha; Ferreira, H. M. N. B. L.; Veloso, J. F. C. A.; Santos, J. M. F. Dos

2004-01-01

62

Ladder Proof of Nonlocality without Inequalities: Theoretical and Experimental Results  

SciTech Connect

We show how a previous demonstration of nonlocality without inequalities for two spin-half particles can be improved so that a greater proportion of the pairs are shown to be subject to a contradiction with local realism. This is achieved by considering more settings of the apparatus at each end. Also, we report on an experimental realization employing a tunable source of polarization entangled photons. The experimental results violate locality (modulo, the efficiency loophole). {copyright} {ital 1997} {ital The American Physical Society}

Boschi, D.; Branca, S.; De Martini, F.; Hardy, L. [Dipartimento di Fisica, Istituto Nazionale di Fisica Nucleare, Istituto Nazionale di Fisica della Materia, Universita La Sapienza, Roma 00185 (Italy)

1997-10-01

63

Computational imaging for aberrated optics (CIAO): experimental results  

NASA Astrophysics Data System (ADS)

This paper presents experimental results obtained with Ziva Corp.'s image processing approach called Computational Imaging for Aberrated Optics (CIAO), which is a multi-image deconvolution algorithm. CIAO enhances the performance of imaging systems by accommodating wavefront error. This accommodation allows the designer to improve system performance or reduce system cost. CIAO has been successfully tested in a wide field of view imaging system, which has significant aberrations. These experimental results show CIAO restoration of high quality images from highly blurred images. Specifically, CIAO allows the pupil to open <50% beyond the diffraction limited aperture, which allows more light capture and higher cut-off resolution.

Saperstein, Robert E.; Ranalli, Eliseo; Mock, Patrick; Husain, Anis

2013-05-01

64

Comparison of calculated and experimental results of fragmenting cylinder experiments  

SciTech Connect

The Grady-Kipp fragmentation model provides a physically based method for determining the fracture and breakup of materials under high loading rates. Recently, this model has been implemented into the CTH Shock Physics Code and has been used to simulate several published experiments. Materials studied in this paper are AerMet 100 steel and a 90% tungsten alloy. The experimental geometry consists of a right circular cylinder filled with an explosive main charge that is initiated at its center. The sudden expansion of the resulting detonation products causes fracture of the cylinder. Strain rates seen in the cylinder are on the order of 10{sup 4} s{sup {minus}1}. The average fragment sizes calculated with the Grady-Kipp fragmentation model successfully replicate the mean fragment size obtained from the experimental fragment distribution. When Poisson statistics are applied to the calculated local average fragment sizes, good correlation is also observed with the shape of the experimental cumulative fragment distribution. The experimental fragmentation results, CTH numerical simulations, and correlation of these numerical results with the experimental data are described.

WILSON,L.T.; REEDAL,D.R.; KIPP,MARLIN E.; MARTINEZ,REINA R.; GRADY,D.E.

2000-06-02

65

Experimental results of the MIT 17 GHz RF gun  

NASA Astrophysics Data System (ADS)

We report on experimental results of a 17 GHz RF photocathode electron gun. This is the first photocathode electron gun to operate at a frequency above 2.856 GHz. The 1.5 cell, ?-mode, copper cavity was tested with 50 ns pulses from a 17.150 GHz klystron amplifier built by Haimson Research Corp. A Bragg filter was used at the RF gun to reduce the reflection of parasitic modes back into the klystron. Coupling hole theory in conjunction with cold test measurements was used to determine the field profile in the RF gun. The particle in cell code MAGIC was used to simulate the beam dynamics in the RF gun. With power levels of 4 MW, the on axis electric field at the cathode exceeds 300 MV/m, corresponding to an average accelerating gradient of 200 MV/m over the first half cell of the gun. Breakdown was observed at power levels above 5 MW. Electron bunches were produced by 20 ?J, 1 ps UV laser pulses impinging on the RF gun copper photocathode and were measured with a Faraday cup to have up to 0.1 nC of charge. This corresponds to a peak current of about 100 A, and a density at the cathode of 8.8 kA/cm2. Multiple output electron bunches were obtained for multiple laser pulses incident on the cathode. Phase scans of laser induced electron emission reveal an overall phase stability of better than +/-20°, corresponding to +/-3 ps synchronization of the laser pulses to the phase of the microwave field. A Browne-Buechner magnetic spectrometer indicated that the RF gun generated 1 MeV electrons with a single shot rms energy spread of less than 2.5%, in good agreement with theoretical predictions.

Brown, W. J.; Trotz, S.; Kreischer, K. E.; Pedrozzi, M.; Shapiro, M. A.; Temkin, R. J.

1999-07-01

66

Behaviour and norms: some experimental results for complex systems modeling  

Microsoft Academic Search

This paper is a review of some experimental results suggesting a way for modeling social interactions. We focus on two classical games, the ultimatum and the dictator game. Using observed facts in laboratory, we ask whether individual rationality could be explained by the presence of a norm of behavior. Norms suggest to individuals what is the appropriate behaviour in social

Roger Waldeck

2008-01-01

67

Experimental Results on Atomic Oxygen Corrosion of Silver.  

National Technical Information Service (NTIS)

The results of an experimental study of the reaction kinetics of silver with atomic oxygen in 10 degree increments over the temperature range of 0 to 70 C is reported. The silver specimens, of the order of 10,000 A in thickness, were prepared by thermal e...

A. T. Fromhold

1988-01-01

68

Thermal simulation and experimental results of a micromachined thermal inclinometer  

Microsoft Academic Search

This paper presents a numerical simulation and experimental results of a one-dimensional thermal inclinometer with sensitivity studies and optimization. The sensor principle consists of one heating resistor placed between two detectors. When the resistor is electrically powered, it creates a symmetrical temperature profile inside a micromachined silicon cavity. By applying a tilt to the sensor, the profile shifts in the

J. Courteaud; P. Combette; N. Crespy; G. Cathebras; A. Giani

2008-01-01

69

Initial experimental results using the noise correlation radar  

NASA Astrophysics Data System (ADS)

Experimental results from recent field testing with the noise correlation radar (NCR) are presented as a proof of concept. In order to understand the effectiveness of the NCR, a predetermined set of measures is established. We discuss the three experimental configurations used in evaluating the system's range resolution/error, robustness to interference, and secure radio frequency (RF) emission. We show that the advanced pulse compression noise (APCN) radar waveform has low range measurement error, is robust to interference, and is spectrally nondeterministic. In addition, we determine that an improvement in range resolution due to phase modulation is achieved as a function of the random code length rather than the compressed pulse length.

Govoni, Mark A.; Silvious, Jerry; Clark, John; Overman, Charles

2013-05-01

70

Design and experimental results for the S805 airfoil  

SciTech Connect

An airfoil for horizontal-axis wind-turbine applications, the S805, has been designed and analyzed theoretically and verified experimentally in the low-turbulence wind tunnel of the Delft University of Technology Low Speed Laboratory, The Netherlands. The two primary objectives of restrained maximum lift, insensitive to roughness, and low profile drag have been achieved. The airfoil also exhibits a docile stall. Comparisons of the theoretical and experimental results show good agreement. Comparisons with other airfoils illustrate the restrained maximum lift coefficient as well as the lower profile-drag coefficients, thus confirming the achievement of the primary objectives.

Somers, D.M. [Airfoils, Inc., State College, PA (United States)

1997-01-01

71

Design and experimental results for the S809 airfoil  

SciTech Connect

A 21-percent-thick, laminar-flow airfoil, the S809, for horizontal-axis wind-turbine applications, has been designed and analyzed theoretically and verified experimentally in the low-turbulence wind tunnel of the Delft University of Technology Low Speed Laboratory, The Netherlands. The two primary objectives of restrained maximum lift, insensitive to roughness, and low profile drag have been achieved. The airfoil also exhibits a docile stall. Comparisons of the theoretical and experimental results show good agreement. Comparisons with other airfoils illustrate the restrained maximum lift coefficient as well as the lower profile-drag coefficients, thus confirming the achievement of the primary objectives.

Somers, D.M. [Airfoils, Inc., State College, PA (United States)

1997-01-01

72

Experimental results for correlation-based wavefront sensing  

SciTech Connect

Correlation wave-front sensing can improve Adaptive Optics (AO) system performance in two keys areas. For point-source-based AO systems, Correlation is more accurate, more robust to changing conditions and provides lower noise than a centroiding algorithm. Experimental results from the Lick AO system and the SSHCL laser AO system confirm this. For remote imaging, Correlation enables the use of extended objects for wave-front sensing. Results from short horizontal-path experiments will show algorithm properties and requirements.

Poyneer, L A; Palmer, D W; LaFortune, K N; Bauman, B

2005-07-01

73

Comparison of SEUTool results to experimental results in boeing radiation tolerant DSP (BDSP C30)  

Microsoft Academic Search

A CAD tool (SEUTool) is analyzed for simulating single-event upsets (SEUs) in large combinational logic circuits. SEUTool cross-section results show excellent agreement with experimental test data taken with the Boeing BDSP C30.

Adam R. Duncan; Varadarajan Srinivasan; Andrew L. Sternberg; William H. Robinson; Bharat L. Bhuva; Lloyd W. Massengill

2005-01-01

74

Theoretical and experimental high energy physics  

SciTech Connect

This report discusses experimental and theoretical work in High Energy Physics. Some topics discussed are: quantum field theory; supersymmetry; cosmology; superstring model; relic photinos; inflationary universe; dark matter; standard model; supernovae; semileptonic decay; quantum Langevin equation; underground neutrino detection at Soudan; strange quark systems; cosmic ray detection; superconducting super collider detectors; and studies of direct photon production. (LSP)

Gasiorowicz, S.; Ruddick, K.

1988-01-01

75

Flicker in erythrocytes. II. Results of experimental studies  

Microsoft Academic Search

The phenomenon of stochastic low-frequency oscillations of erythrocyte cell membrane, termed usually the flicker of erythrocytes,\\u000a is reviewed. The first part [Biol. Membrany (Rus.), 2009, vol. 26, no. 5, pp. 352–369] describes theoretical models of erythrocyte flickering and the registration techniques.\\u000a In the second part presented below the main experimental results are reviewed, the problem of identification of acting mechanisms

V. L. Kononenko

2009-01-01

76

Impact ionization MOS (I-MOS)Part II: experimental results  

Microsoft Academic Search

Part I of this paper dealt with the fundamental understanding of device physics and circuit design in a novel transistor, based on the field-effect control of impact-ionization (I-MOS). This paper focuses on experimental results obtained on various silicon-based prototypes of the I-MOS. The fabricated p-channel I-MOS devices showed extremely abrupt transitions from the OFF state to the ON state with

Kailash Gopalakrishnan; Raymond Woo; Christoph Jungemann; Peter B. Griffin; James D. Plummer

2005-01-01

77

Training emotional intelligence: Presenting the results of an experimental study  

Microsoft Academic Search

This presentation outlines the results of an eighteen month study examining the effect of an emotions focused training intervention on the emotional intelligence of employees from a large public sector organisation. Utilising an experimental methodology, 280 staff attended a two-day program focused on training emotional intelligence skills and abilities. These interventions were created around Mayer and Salovey’s four-branch model of

Jane P Murray; Peter J Jordan; Neal M Ashkanasy

2006-01-01

78

Diffusion of dissolved carbonate in magmas: Experimental results and applications  

NASA Astrophysics Data System (ADS)

The diffusivity of dissolved carbonate in sodium aluminosilicate (60% SiO 2, 30% Na 2O, 10% Al 2O 3) and iron-free "basalt" melts was measured by a 14C thin-source tracer technique at conditions of combined high temperature and high pressure, ranging from 800°C to 1350°C and 0.5 to 18 kbar for the simple melt and 1350° to 1500°C at 15 kbar for the haplobasalt melt. The two melts have similar dissolved carbonate transport properties, expressed for the simple system at 0.5 kbar by: Dcarbonate=3.559exp(-46,600/RT) The pressure dependence at 1200°C is given by: Dcarbonate=4.13×10 -7exp(-11.02P/RT) The activation energy of 46.6 kcal/mole is low relative to expected values for small, highly-charged cations, suggesting that the actual diffusing species is a larger carbonate anion. This interpretation is supported by the 11 cm 3/mole activation volume, which corresponds to twice the molar volume of oxygen anions. Because the 14C diffusion gradients conform quite well to a constant-diffusivity, thin-source model, there can be no strong dependence of carbonate diffusivity upon dissolved carbonate content, at least in the 0-0.2 wt.% range represented by the experimental profiles. Carbonate diffusion is markedly different from previously determined systematics for water, being 1-2 orders of magnitude slower in granitic magmas and considerably faster in basalts. This difference can result in diffusional fractionation of CO 2 and H 2O in magmas, which may be most significant in small-scale processes such as growth of vapor bubbles and formation of some types of glass inclusions in phenocrysts. The new data also place constraints on the rate at which CO 2-dominated fluid bubbles can actually grow. Under more or less isothermal conditions at ˜ 10 kbar, the growth rate is on the order of 1 mm/day, depending upon the degree of supersaturation in CO 2. When combined with knowledge of initial CO 2 contents of magmas and observed characteristics of dispersed bubbles (e.g., in ocean-floor basalt glasses), the diffusivity data may expedite the reconstruction of magma decompression paths.

Watson, E. Bruce; Sneeringer, Mark A.; Ross, Alan

1982-12-01

79

Novel results on low energy neutrino physics  

NASA Astrophysics Data System (ADS)

Many progresses have been achieved in the study of low energy neutrinos from Sun and Earth. In the solar neutrinos the flux from 7Be has been measured with a total error <5% (introducing strong constraints also on the pp flux), while the day/night effect in that energy region has been determined at 1%. The 8B neutrinos have been detected with a threshold down to 3 MeV, while the solar neutrinos flux from pep reaction has been measured together with a stringent limit on CNO. These results give the experimental proof of the neutrino oscillation in vacuum and the validation of the MSW-LMA model in that region, while the day/night allows the isolation of the LMA solution by means of the solar neutrinos only, without the assumption of CPT symmetry. The evidence of the antineutrinos produced within the Earth by radioactive decays is now very robust, but more statistics is needed to clearly estimate the radiogenic contribution to the terrestrial caloric energy.

Bellini, Gianpaolo

2012-07-01

80

Design and experimental results for the S814 airfoil  

SciTech Connect

A 24-percent-thick airfoil, the S814, for the root region of a horizontal-axis wind-turbine blade has been designed and analyzed theoretically and verified experimentally in the low-turbulence wind tunnel of the Delft University of Technology Low Speed Laboratory, The Netherlands. The two primary objectives of high maximum lift, insensitive to roughness, and low profile drag have been achieved. The constraints on the pitching moment and the airfoil thickness have been satisfied. Comparisons of the theoretical and experimental results show good agreement with the exception of maximum lift which is overpredicted. Comparisons with other airfoils illustrate the higher maximum lift and the lower profile drag of the S814 airfoil, thus confirming the achievement of the objectives.

Somers, D.M. [Airfoils, Inc., State College, PA (United States)

1997-01-01

81

Computed-tomography imaging spectrometer: experimental calibration and reconstruction results  

NASA Astrophysics Data System (ADS)

A temporally and spatially nonscanning imaging spectrometer is described in terms of computed-tomography concepts, specifically the central-slice theorem. A sequence of three transmission sinusoidal-phase gratings rotated in 60 deg increments achieves dispersion in multiple directions and into multiple orders. The dispersed images of the system's field stop are interpreted as two-dimensional projections of a three-dimensional (x, y, lambda ) object cube. Because of the size of the finite focal-plane array, this imaging spectrometer is an example of a limited-view-angle tomographic system. The imaging spectrometer's point spread function is measured experimentally as a function of wavelength and position in the field of view. Reconstruction of the object cube is then achieved through the maximum-likelihood, expectation-maximization algorithm under the assumption of a Poisson likelihood law. Experimental results indicate that the instrument performs well in the case of broadband and narrow-band emitters.

Descour, Michael; Dereniak, Eustace

1995-08-01

82

Experimental results concerning global observables from the CERN SPS heavy ion program  

SciTech Connect

A brief overview is given of experimental results obtained during the initial operation of the heavy-ion program at the CERN SPS during the period 1986--1988. This paper confines itself to a presentation of results on so-called global observables, such as energy flow and multiplicity distributions, and on information extracted from them. Of particular interest among the latter are an estimate of the magnitude and spatial distribution of the energy density attained. 3 refs., 27 figs.

Young, G.R.

1990-06-01

83

Experimental investigations of recent anomalous results in superconductivity  

NASA Astrophysics Data System (ADS)

This thesis examines three recent anomalous results associated with irreversibility in type-II superconductivity: (1) The magnetic properties of the predicted superconductors LiBeH3 and Li2BeH 4, (2) the paramagnetic transition near T = Tc in Nb, and (3) a noise transition in a YBa2Cu3O7-delta thin film near the vortex-solid transition. The investigation of Li 2BeH4 and LiBeH3 was prompted by theoretical predictions of room-temperature superconductivity for Li2BeH4 and LiBeH3 and a recent report that Li2BeH4 showed magnetic irreversibilities similar to those of type-II superconductors. A modified experimental method is introduced in order to avoid artifacts due to background signals. The resulting data is suggestive of a superparamagnetic impurity from one of the reagents used in the synthesis and after subtracting this contribution, the temperature-dependent susceptibilities of Li2 BeH4 and LiBeH3 are estimated. However, no magnetic irreversibility suggestive of superconductivity is observed. The anomalous paramagnetic transition in Nb is intriguing because Nb does not share the d-wave order parameter symmetry often invoked to explain the phenomenon in other superconductors. A modified experimental method was developed in order to avoid instrumental artifacts known to produce a similar apparently paramagnetic response, but the results of this method indicate that the paramagnetic response is a physical property of the sample. Finally, a very sharp noise transition in a YBa2Cu3O7-delta thin film was found to be distinct from previously reported features in the voltage noise commonly associated with vortex fluctuations near the irreversibility line. In each of these three cases the examination of experimental techniques is an integral part of the investigation of novel vortex behavior near the onset of irreversibility.

Souw, Victor K.

84

ANOVA parameters influence in LCF experimental data and simulation results  

NASA Astrophysics Data System (ADS)

The virtual design of components undergoing thermo mechanical fatigue (TMF) and plastic strains is usually run in many phases. The numerical finite element method gives a useful instrument which becomes increasingly effective as the geometrical and numerical modelling gets more accurate. The constitutive model definition plays an important role in the effectiveness of the numerical simulation [1, 2] as, for example, shown in Figure 1. In this picture it is shown how a good cyclic plasticity constitutive model can simulate a cyclic load experiment. The component life estimation is the subsequent phase and it needs complex damage and life estimation models [3-5] which take into account of several parameters and phenomena contributing to damage and life duration. The calibration of these constitutive and damage models requires an accurate testing activity. In the present paper the main topic of the research activity is to investigate whether the parameters, which result to be influent in the experimental activity, influence the numerical simulations, thus defining the effectiveness of the models in taking into account of all the phenomena actually influencing the life of the component. To obtain this aim a procedure to tune the parameters needed to estimate the life of mechanical components undergoing TMF and plastic strains is presented for commercial steel. This procedure aims to be easy and to allow calibrating both material constitutive model (for the numerical structural simulation) and the damage and life model (for life assessment). The procedure has been applied to specimens. The experimental activity has been developed on three sets of tests run at several temperatures: static tests, high cycle fatigue (HCF) tests, low cycle fatigue (LCF) tests. The numerical structural FEM simulations have been run on a commercial non linear solver, ABAQUS®6.8. The simulations replied the experimental tests. The stress, strain, thermal results from the thermo structural FEM simulations have been used to assess specimens life by means of several damage models implemented in two dedicated softwares. One of them is commercial life estimation software and the second one has been developed by the present research group. The life estimations results obtained from the two softwares and from the damage models have been compared with experimental duration in different test conditions. A statistical analysis of life estimation results allowed evaluating the effectiveness of the procedure.

Delprete, C.; Sesanaa, R.; Vercelli, A.

2010-06-01

85

Experimental results for multichannel feedforward ANC with noninvasive system identification  

PubMed

This paper presents experimental validation of a class of algorithms designed to enable active noise control (ANC) to function in environments when transfer functions change significantly over time. The experimental results presented are for broadband, local quieting in a diffuse field using a multichannel ANC system. The reverberant enclosure is an ordinary room, measuring approximately 1.4 x 2.4 x 2.4 m3 and containing a seated occupant, with six microphones defining the quiet zone near the occupant's ears. The control system uses a single reference signal and two error channels to drive four secondary sources. Using an ideal reference sensor, reduction in sound pressure level is obtained at the quiet-zone microphones averaged over the frequency range 50 to 1000 Hz with an occupant seated in the room. Two main results are presented: first for an adaptive cancelling algorithm that uses static system models, and second for the same algorithm joined with a noninvasive real-time system identification algorithm. In the first case better than 23 dB of performance is obtained if the occupant remains still through calibration and testing. In the second case, approximately 18 dB is obtained at the error microphones regardless of the motion of the occupant. PMID:10790030

Nowlin; Guthart; Toth

2000-04-01

86

Natural convection airflow and heat transport in buildings: experimental results  

SciTech Connect

Observations of natural convection airflow in passive solar buildings are described. Particular results are given for two buildings supplementing other data already published. A number of generalizations based on the monitoring of the 15 buildings are presented. It is concluded that energy can be reasonably well distributed throughout a building by natural convection provided suitable openings are present and that the direction of heat transport is either horizontally across or upward.

Balcomb, J.D.; Jones, G.F.

1985-01-01

87

Experimental and theoretical high energy physics  

NASA Astrophysics Data System (ADS)

We are carrying out a research program in high energy experimental particle physics. Studies of high energy hadronic interactions and leptoproduction processes continue using several experimental techniques. Progress has been made on the study of multiparticle production processes in nuclei. Ultra-high energy cosmic ray nucleus-nucleus interactions have been investigated by the Japanese American Cosmic Emulsion Experiment (JACEE) using balloon-borne emulsion chamber detectors. In the area of particle astrophysics, our studies of cosmic ray nuclear interactions have enabled us to make the world's most accurate determination of the composition of the cosmic rays above 10(13) eV. We have the only detector that can observe interaction vertices and identify particles at energies up to 10 to 15 eV. Our observations are getting close to placing limits on the acceleration mechanisms postulated for pulsars in which the spin and magnetic moment axes are at different angles. In June, 1989 approval was given by NASA for our participation in the Space Station program. The SCINATT experiment will make use of emulsion chamber detectors, similar to the planned JACEE hybrid balloon flight detectors. These detectors will permit precise determination of secondary particle charges, momenta and rapidities, and the accumulation of data will be at least a factor of 10 to 100 greater than in balloon experiments.

Boulware, David

88

Ultrasonic scattering by blood: theories, experimental results and biomedical applications  

NASA Astrophysics Data System (ADS)

In this paper, theoretical and experimental efforts that have been undertaken to better understand the phenomenon of ultrasonic scattering in blood will be reviewed. This subject is of interest in biology and medicine because the echoes generated by blood are used to extract blood velocity by ultrasonic Doppler flow and imaging devices. In the course of these investigations it became clear that ultrasonic scattering from blood is dependent upon such hematological and hemodynamic properties of blood as hematocrit, plasma protein concentration, flow rate and flow cycle duration. Several aspects of these experimental results have been successfully modeled by recent theoretical developments. An unexpected consequence of these efforts is that ultrasound appears to be a viable tool for blood flow visualization and hemodynamic measurements. Two unique hemodynamic phenomena that have never been reported in the hemodynamic literature have been observed: the black hole, a low echogenic zone in the center stream of whole blood flowing in a blood vessel under steady flow and the collapsing ring, an echogenic ring appearing near the periphery of a vessel at the beginning of a flow cycle, converging toward the center, and eventually collapsing during pulsatile flow. Similar observations have been made during clinical scanning of patients.

Shung, K. Kirk

2002-05-01

89

Aeolian Simulations: A Comparison of Numerical and Experimental Results  

NASA Astrophysics Data System (ADS)

Aeolian processes are a major geomorphic agent on solid planetary bodies with atmospheres (Earth, Mars, Venus, and Titan). This paper describes preliminary efforts to model aeolian saltation using computational fluid dynamics (CFD) and to compare the results with those obtained in wind tunnel testing conducted in the Planetary Aeolian Laboratory at NASA Ames Research Center at ambient pressure. The end goal of the project is to develop an experimentally validated CFD approach for modeling aeolian sediment transport on Titan and other planetary bodies. The MARSWIT open-circuit tunnel in this work was specifically designed for atmospheric boundary layer studies. It is a variable-speed, continuous flow tunnel with a test section 1.0 m by 1.2 m in size; the tunnel is able to operate at pressures from 10 millibar to one atmosphere. Flow trips near the tunnel inlet ensure a fully developed, turbulent boundary layer in the test section. Wind speed and axial velocity profiles can be measured with a traversing pitot tube. In this study, sieved walnut shell particles (Greeley et al. 1976) with a density of ~1.1 g/cm3 were used to correlate the low gravity conditions and low sediment density on a body of interest to that of Earth. This sediment was placed in the tunnel, and the freestream airspeed raised to 5.4 m/s. A Phantom v12 camera imaged the resulting particle motion at 1000 frames per second, which was analyzed with ImageJ open-source software (Fig. 1). Airflow in the tunnel was modeled with FLUENT, a commercial CFD program. The turbulent scheme used in FLUENT to obtain closed-form solutions to the Navier-Stokes equations was a 1st Order, k-epsilon model. These methods produced computational velocity profiles that agree with experimental data to within 5-10%. Once modeling of the flow field had been achieved, a Euler-Lagrangian scheme was employed, treating the particles as spheres and tracking each particle at its center. The particles are assumed to interact with wall boundaries via perfectly elastic collisions. Calculated particle trajectories agree closely with experimental results (Fig. 2).

Mathews, O.; Burr, D. M.; Bridges, N. T.; Lyne, J. E.; Marshall, J. R.; Greeley, R.; White, B. R.; Hills, J.; Smith, K.; Prissel, T. C.; Aliaga-Caro, J. F.

2010-12-01

90

Silicon drift detector with reduced lateral diffusion:experimental results  

NASA Astrophysics Data System (ADS)

In a standard multi-anode silicon drift detector electron cloud broadening during the drifting towards the anode pixels deteriorates the energy and position resolution. This makes the detector less applicable for detection of low-energy X-rays. The signal charge sharing between several anodes can be eliminated by introducing sawtooth-shaped p+ field strips. The sawtooth structure results in small electric fields directed parallel to the sensor surface and perpendicular to the drift direction which produce gutters. The drifting electrons are confined in these gutters of one saw tooth period wide. For a detector with a sawtooth period of 500?m, we have measured the maximum number of fully confined electrons as a function of the potential gutter depth induced by different sawtooth angles.

Šonský, J.; Valk, H.; Huizenga, J.; Hollander, R. W.; van Eijk, C. W. E.; Sarro, P. M.

2000-01-01

91

Experimental feature in the primary-proton flux at energies above 10 TeV according to the results of searches for primary particles in nuclear emulsions exposed in the stratosphere (RUNJOB Experiment)  

NASA Astrophysics Data System (ADS)

In the RUNJOB experiment, a long-term exposure of x-ray emulsion chambers in the stratosphere from 1995 to 1999 with the aim of studying the composition and spectra of primary cosmic particles in the energy range 10-1000 TeV per nucleon revealed about 50% proton tracks. The remaining events of the proton group did not feature any candidate for a track of a singly charged particle within the search region determined from measurements of the coordinates of background nuclei going close to the sought track. Methodological factors that could explain this experimental observation are considered. A possible physical reason associated with the presence of a neutral component in the flux of primary protons in the energy region above 10 TeV is also analyzed.

Zayarnaya, I. S.

2008-02-01

92

Integrated radar-camera security system: experimental results  

NASA Astrophysics Data System (ADS)

The nature of the recent military conflicts and terrorist attacks along with the necessity to protect bases, convoys and patrols have made a serious impact on the development of more effective security systems. Current widely-used perimeter protection systems with zone sensors will soon be replaced with multi-sensor systems. Multi-sensor systems can utilize day/night cameras, IR uncooled thermal cameras, and millimeter-wave radars which detect radiation reflected from targets. Ranges of detection, recognition and identification for all targets depend on the parameters of the sensors used and of the observed scene itself. In this paper two essential issues connected with multispectral systems are described. We will focus on describing the autonomous method of the system regarding object detection, tracking, identification, localization and alarm notifications. We will also present the possibility of configuring the system as a stationary, mobile or portable device as in our experimental results.

Zyczkowski, M.; Palka, N.; Trzcinski, T.; Dulski, R.; Kastek, M.; Trzaskawka, P.

2011-05-01

93

Experimental results to study astrophysical plasma jets using Intense Lasers  

NASA Astrophysics Data System (ADS)

We present experimental results of plasma jet, interacted with an ambient medium, using intense lasers to investigate the complex features of astrophysical jets. This experiment was performed in France at the LULI facility, Ecole Polytechnique, using one long pulse laser to generate the jet and a short pulse laser to probe it by proton radiography. A foam filled cone target was used to generate high velocity plasma jet, and a gas jet nozzle produced the well known ambient medium. Using visible pyrometry and interferometry, we were able to measure the jet velocity and electronic density. We get a panel of measurements at various gas density and time delay. From these measurements, we could underline the growth of a perturbed shape of the jet interaction with the ambient medium. The reason of this last observation is still in debate and will be presented in the article.

Loupias, B.; Gregory, C. D.; Falize, E.; Waugh, J.; Seiichi, D.; Pikuz, S.; Kuramitsu, Y.; Ravasio, A.; Bouquet, S.; Michaut, C.; Barroso, P.; Rabec Le Gloahec, M.; Nazarov, W.; Takabe, H.; Sakawa, Y.; Woolsey, N.; Koenig, M.

2009-08-01

94

Robotic follower experimentation results: ready for FCS block I  

NASA Astrophysics Data System (ADS)

Robotics is a fundamental enabling technology required to meet the U.S. Army's vision to be a strategically responsive force capable of domination across the entire spectrum of conflict. The U. S. Army Research, Development and Engineering Command (RDECOM) Tank Automotive Research, Development & Engineering Center (TARDEC), in partnership with the U.S. Army Research Laboratory, is developing a leader-follower capability for Future Combat Systems. The Robotic Follower Advanced Technology Demonstration (ATD) utilizes a manned leader to provide a highlevel proofing of the follower's path, which operates with minimal user intervention. This paper will give a programmatic overview and discuss both the technical approach and operational experimentation results obtained during testing conducted at Ft. Bliss, New Mexico in February-March 2003.

Jaczkowski, Jeffrey J.

2003-09-01

95

Experimental results on indoor electromagnetic wave absorber using magnetic wood  

NASA Astrophysics Data System (ADS)

The purpose of this paper is to propose a new type of indoor electromagnetic wave absorber using magnetic wood. This magnetic wood has good electromagnetic wave absorbing characteristics, a low specific gravity, a wood texture and other wood characteristics and can be easily processed. Electromagnetic wave absorbing characteristics were measured for four types of magnetic wood. The sandwich-type magnetic wood demonstrated the best wave absorbing characteristics among the four types of magnetic wood that were studied. The experimental results showed that the proposed indoor electromagnetic wave absorber can be used to suppress the transmission and reception of cellular phone and Personal Handy Phone System (PHS) signals and can be used as a cross protection for indoor wireless Local Area Networks (LAN). This wood can be processed for use in furniture, building materials, and other applications.

Oka, Hideo; Narita, Koichi; Osada, Hiroshi; Seki, Kyoushirou

2002-05-01

96

From Deuterium to Free Neutrons - Recent Experimental Results  

NASA Astrophysics Data System (ADS)

Lepton scattering has long been used to gather data on the internal structure of both protons and neutrons. Assuming isospin symmetry, these data can be used to pin down the contributions of both u and d quarks to the spatial and momentum-spin structure of the nucleon and its excitations. In this context, information on the neutron is crucial and is typically obtained from experiments on few-body nuclear targets (predominantly ^3He and deuterium). However, the need to account for binding effects complicates the interpretation of these experiments. On the other hand, detailed studies of the reaction mechanism can yield important new information on the structure of few-body nuclei and the interplay of nuclear and quark degrees of freedom. Recent theoretical and experimental advances have allowed us to make significant progress on both fronts -- a cleaner extraction of neutron properties from nuclear data and a better understanding of nuclear modifications of the bound neutron structure. I will concentrate on recent results on the deuteron. I will present a new extraction of neutron spin structure functions in the resonance and large-x region (from the EG1 experiment with CLAS at Jefferson Lab). The same data can also be used for a detailed comparison with modern calculations of quasi-elastic spin-dependent scattering on the deuteron. A second experimental program with CLAS uses the technique of ``spectator tagging'' to extract the unpolarized structure functions of the neutron with minimal uncertainties from nuclear effects. By mapping out the dependence of the cross section on the ``spectator'' momentum, we can learn about final state interactions between the struck nucleon and the spectator, as well as modifications of the neutron structure due to nuclear binding. I will present preliminary results from the ``BoNuS'' experiment which pushed the detection limit of the spectator proton down to momenta of 70 MeV/c, where nuclear corrections should become small.

Kuhn, Sebastian

2009-05-01

97

[Experimental and theoretical high energy physics program  

SciTech Connect

Experimental and theoretical high-energy physics research at Purdue is summarized in a number of reports. Subjects treated include the following: the CLEO experiment for the study of heavy flavor physics; gas microstrip detectors; particle astrophysics; affine Kac{endash}Moody algebra; nonperturbative mass bounds on scalar and fermion systems due to triviality and vacuum stability constraints; resonance neutrino oscillations; e{sup +}e{sup {minus}} collisions at CERN; {bar p}{endash}p collisions at FNAL; accelerator physics at Fermilab; development work for the SDC detector at SSC; TOPAZ; D-zero physics; physics beyond the standard model; and the Collider Detector at Fermilab. (RWR)

Finley, J.; Gaidos, J.A.; Loeffler, F.J.; McIlwain, R.L.; Miller, D.H.; Palfrey, T.R.; Shibata, E.I.; Shipsey, I.P.

1993-04-01

98

Experimental Results of Guided Wave Travel Time Tomography  

NASA Astrophysics Data System (ADS)

Corrosion is one of the industries major issues regarding the integrity of assets. Currently inspections are conducted at regular intervals to ensure a sufficient integrity level of these assets. Both economical and social requirements are pushing the industry to even higher levels of availability, reliability and safety of installations. The concept of predictive maintenance using permanent sensors that monitor the integrity of an installation is an interesting addition to the current method of periodic inspections reducing uncertainty and extending inspection intervals. Guided wave travel time tomography is a promising method to monitor the wall thickness quantitatively over large areas. Obviously the robustness and reliability of such a monitoring system is of paramount importance. Laboratory experiments have been carried out on a 10'' pipe with a nominal wall thickness of 8 mm. Multiple, inline defects have been created with a realistic morphology. The depth of the defects was increased stepwise from 0.5 mm to 2 mm. Additionally the influences of the presence of liquid inside the pipe and surface roughness have been evaluated as well. Experimental results show that this method is capable of providing quantitative wall thickness information over a distance of 4 meter, with a sufficient accuracy such that results can be used for trending. The method has no problems imaging multiple defects.

Volker, Arno; Mast, Arjan; Bloom, Joost

2010-02-01

99

Experimental results of guided wave travel time tomography  

NASA Astrophysics Data System (ADS)

Corrosion is one of the industries major issues regarding the integrity of assets. Currently inspections are conducted at regular intervals to ensure a sufficient integrity level of these assets. Cost reduction while maintaining a high level of reliability and safety of installations is a major challenge. The concept of predictive maintenance using permanent sensors that monitor the integrity of an installation matches very well with the objective to reduce cost while maintaining a high safety level. Guided waves are very attractive for permanent monitoring systems because it provides a wall thickness map in between two sensor rings. The wall thickness map provides quantitative information about the remaining wall thickness, location and extent of the corrosion. The performance of guided wave tomography has been evaluated experimentally assessing the sizing accuracy and the smallest corrosion spots that can be detected with this technology. The results show accurate sizing, with a sizing accuracy better than 10% of the nominal wall thickness. Additionally, the maximum distance between the transmitter and receiver rings and the presence of different coatings has been evaluated. The results demonstrate the robustness of the technology under a range of practical conditions.

Volker, Arno; Vos, Hendrik

2012-05-01

100

FRVT 2006 and ICE 2006 large-scale experimental results.  

PubMed

This paper describes the large-scale experimental results from the Face Recognition Vendor Test (FRVT) 2006 and the Iris Challenge Evaluation (ICE) 2006. The FRVT 2006 looked at recognition from high-resolution still frontal face images and 3D face images, and measured performance for still frontal face images taken under controlled and uncontrolled illumination. The ICE 2006 evaluation reported verification performance for both left and right irises. The images in the ICE 2006 intentionally represent a broader range of quality than the ICE 2006 sensor would normally acquire. This includes images that did not pass the quality control software embedded in the sensor. The FRVT 2006 results from controlled still and 3D images document at least an order-of-magnitude improvement in recognition performance over the FRVT 2002. The FRVT 2006 and the ICE 2006 compared recognition performance from high-resolution still frontal face images, 3D face images, and the single-iris images. On the FRVT 2006 and the ICE 2006 data sets, recognition performance was comparable for high-resolution frontal face, 3D face, and the iris images. In an experiment comparing human and algorithms on matching face identity across changes in illumination on frontal face images, the best performing algorithms were more accurate than humans on unfamiliar faces. PMID:20299708

Phillips, P Jonathon; Scruggs, W Todd; O'Toole, Alice J; Flynn, Patrick J; Bowyer, Kevin W; Schott, Cathy L; Sharpe, Matthew

2010-05-01

101

Experimental Results of Integrated Refrigeration and Storage System Testing  

NASA Astrophysics Data System (ADS)

Launch operations engineers at the Kennedy Space Center have identified an Integrated Refrigeration and Storage system as a promising technology to reduce launch costs and enable advanced cryogenic operations. This system uses a closed cycle Brayton refrigerator to remove energy from the stored cryogenic propellant. This allows for control of the temperature and pressure of the fluid, and enables advanced operations such as zero boil off storage and zero loss transfer. If required, this also can serve as a propellant densification system or liquefier. However, the behavior of the fluid in this type of system is different than typical cryogenic storage systems, and there will be a learning curve associated with its use. A 400 liter research cryostat has been designed, fabricated and delivered to KSC to test the thermofluid behavior of liquid oxygen as energy is removed from the cryogen by a simulated DC cycle cryocooler. Results of the initial testing phase focusing on heat exchanger characterization and zero loss storage operations using liquid oxygen are presented in this paper. Future plans for testing of oxygen densification tests and oxygen liquefaction tests will also be discussed.

Notardonato, W. U.; Johnson, W. L.; Oliveira, J.; Jumper, K.

2010-04-01

102

Experimental Results in DIS, SIDIS and DES from Jefferson Lab  

SciTech Connect

Jefferson Lab's electron accelerator in its present incarnation, with a maximum beam energy slightly above 6 GeV, has already enabled a large number of experiments expanding our knowledge of nucleon and nuclear structure (especially in Deep Inelastic Scattering—DIS—at moderately high x, and in the resonance region). Several pioneering experiments have yielded first results on Deeply Virtual Compton Scattering (DVCS) and other Deep Exclusive Processes (DES), and the exploration of the rich landscape of transverse momentum-dependent (TMD) structure functions using Semi-Inclusive electron scattering (SIDIS) has begun. With the upgrade of CEBAF to 12 GeV now underway, a significantly larger kinematic space will become available. The 12 GeV program taking shape will complete a detailed mapping of inclusive, TMD and generalized distribution functions for quarks, antiquarks and gluons in the valence region and beyond.

Sebastian Kuhn

2011-07-01

103

Experimental Results in DIS, SIDIS and DES from Jefferson Lab  

SciTech Connect

Jefferson Lab's electron accelerator in its present incarnation, with a maximum beam energy slightly above 6 GeV, has already enabled a large number of experiments expanding our knowledge of nucleon and nuclear structure (especially in Deep Inelastic Scattering--DIS--at moderately high x, and in the resonance region). Several pioneering experiments have yielded first results on Deeply Virtual Compton Scattering (DVCS) and other Deep Exclusive Processes (DES), and the exploration of the rich landscape of transverse momentum-dependent (TMD) structure functions using Semi-Inclusive electron scattering (SIDIS) has begun. With the upgrade of CEBAF to 12 GeV now underway, a significantly larger kinematic space will become available. The 12 GeV program taking shape will complete a detailed mapping of inclusive, TMD and generalized distribution functions for quarks, antiquarks and gluons in the valence region and beyond.

Kuhn, Sebastian E. [Old Dominion University, Norfolk, VA 23529 (United States)

2011-07-15

104

Experimental results on V-M type pulse tube refrigerator  

NASA Astrophysics Data System (ADS)

This article mainly introduces experimental results on a new type pulse tube refrigerator named as V-M type pulse tube refrigerator. The main difference from Stirling type or G-M type pulse tube refrigerator is that thermal compressor similar to that of a V-M cryocooler is used instead of mechanical compressor. By using temperature difference between room temperature and liquid nitrogen, pressure wave with high to low pressure ratio around 1.2 is obtained. This pressure wave is used to generate cooling effect at the cold end. With a 20 K pre-cooler, this machine reaches lowest temperature 5.25 K by using helium 4 at 0.77 Hz, 19 bar charge pressure. DC flow plays an important role in our system. It not only influences the final obtainable lowest temperature, but also is used to increase cold end cool-down speed. Total volume of the V-M type pulse tube refrigerator is around 3.3 l. However, dead volume inside rotor housing occupies about 2.8 l and can be much reduced.

Dai, Wei; Matsubara, Yoichi; Kobayashi, Hisayasu

2002-06-01

105

Experimental results of a 30 m, 3-core HTSC cable  

NASA Astrophysics Data System (ADS)

A high temperature superconducting (HTSC) cable is expected to transport large electric power with a compact size because of its high critical current density. We have been developing a 3-core 66 kV class HTSC cable, which is applied to the ?150 mm duct, and is composed of a conductor and a shield wound with Ag-Mn sheathed Bi-2223 tapes, electrical insulation with polypropylene laminated paper impregnated with liquid nitrogen and thermal insulation with co-axial corrugated pipes. A 30 m, 3-core cable system has been constructed to verify the 3-core performance after its production, laying and cooling. The cable had good performance to mechanical stress in the factory process. The critical current of the cable was more than 2.4 kA at 77 K. The AC loss of the conductor part was 0.5 W/m/phase at 1 kA rms, which agreed well with the calculated value of the spiral pitch adjustment technique. A 130 kV rms AC was successfully applied without any change in tan? and capacitance. As a next step, a 100 m HTSC cable has been designed and developed based on these experimental results.

Masuda, Takato; Kato, Takeshi; Yumura, Hiroyasu; Hirose, Masayuki; Isojima, Shigeki; Honjo, Shoichi; Matsuo, Kimiyoshi; Mimura, Tomoo; Takahashi, Yoshihisa

2002-08-01

106

Stemming Temperature Changes During Emplacement: Experimental Results and Analysis.  

National Technical Information Service (NTIS)

The process of stemming a deep hole with magnetite, which was initially hotter or cooler than the ambient downhole temperature, was investigated experimentally. The specific objective of the experiment was to determine the temperature changes that occur a...

W. Stein W. J. Comfort

1989-01-01

107

Experimental setup for high energy photoemission using synchrotron radiation  

NASA Astrophysics Data System (ADS)

The instrument VOLPE (volume photoemission from solids) is an experimental setup dedicated to high energy photoemission (PE) experiments. The instrument is equipped with an electrostatic hemispherical spectrometer especially designed to analyze high energy electrons (up to 10 keV) with high resolving power. In order to attain an energy resolution of a few tens of millielectron volts, we designed and constructed a dedicated input lens system, high stability power supplies, and a low dark-count detector and readout electronics. The system has been tested and is now operational on the ID16 beamline at European Synchrotron Radiation Facility, where an optical layout has been developed to perform high energy, high resolution PE experiments. First results show an overall energy resolution (electron + photon) of 71+/-7 meV at 5934 eV. The effective attenuation length of the photoelectrons is estimated to be 5+/-0.5 nm at a kinetic energy of 5 keV.

Torelli, P.; Sacchi, M.; Cautero, G.; Cautero, M.; Krastanov, B.; Lacovig, P.; Pittana, P.; Sergo, R.; Tommasini, R.; Fondacaro, A.; Offi, F.; Paolicelli, G.; Stefani, G.; Grioni, M.; Verbeni, R.; Monaco, G.; Panaccione, G.

2005-02-01

108

New experimental results for a vector boson A  

NASA Astrophysics Data System (ADS)

The search for a new vector boson, A', in the test run of A' EXperiment (APEX) results in a limit for a weak coupling ?' 10-6 ? to electrons (?=e^2/4?) in the mass range 175 MeV < mA'< 250 MeV. New vector bosons with such small couplings arise naturally from a small kinetic mixing of the ``dark photon'' A' with the photon --- one of the very few ways in which new forces can couple to the Standard Model --- and have received considerable attention as an explanation of various dark matter related anomalies. A' bosons are produced by radiation off an electron beam, and could appear as narrow resonances with small production cross-section in the trident e^+e^- spectrum. We plan to search for the A' by using the CEBAF electron beam at energies of 1--4 GeV incident on 0.5-10% radiation length multi-foil Tungsten targets, and measure the resulting e^+e^- pairs using the High Resolution Spectrometers and a septum magnet in Hall A at Jefferson Lab. With a 33-day run, the experiment will achieve very good sensitivity because the statistics of e^+e^- pairs will be ˜10,000 times larger in the explored mass range than in any previous search for the A' boson. This talk will discuss the experiment and present the

Wojtsekhowski, Bogdan; Essig, Rouven; Schuster, Philip; Toro, Natalia

2012-03-01

109

High Phase Order Induction Motors??? Part II. Experimental Results  

Microsoft Academic Search

Experimental tests have been carried out on a small induction motor connected for six phases and for nine phases. These include torque measurements over the entire speed range and load tests with balanced source and with one phase open. Some of the machine impedances, including sequence impedances, were measured and these generally agree with predicted values. The motor was subjected

E. A. Klingshirn

1983-01-01

110

Overview of experimental results on HL2A  

Microsoft Academic Search

Significant experimental advances have been made on the HL-2A tokamak along with substantial improvement and development of the hardware. A spontaneous particle transport barrier has been observed in Ohmic discharges without any external momentum input. The barrier was evidenced by a density perturbation study using modulated supersonic molecular beam injection (SMBI) and microwave reflectometry. The new features of the non-local

X. R. Duan; X. T. Ding; J. Q. Dong; Q. W. Yang; L. W. Yan; Yi Liu; X. L. Zou; D. Q. Liu; W. M. Xuan; L. Y. Chen; J. Rao; X. M. Song; W. C. Mao; Q. M. Wang; Z. Cao; B. Li; J. Y. Cao; G. J. Lei; J. H. Zhang; X. D. Li; S. J. Wang; A. D. Liu; M. N. Bu; Y. H. Chen; W. Chen; J. Cheng; C. H. Cui; Z. Y. Cui; Z. C. Deng; Y. B. Dong; B. B. Feng; Q. D. Gao; X. Y. Han; W. Y. Hong; H. T. Hu; M. Huang; Y. Huang; X. Q. Ji; Z. H. Kang; T. Lan; G. S. Li; H. J. Li; Qing Li; Qiang Li; W. Li; Y. G. Li; Z. J. Li; Z. T. Liu; C. W. Luo; X. H. Mao; Y. D. Pan; J. F. Peng; K. Shao; X. Y. Song; H. J. Sun; A. K. Wang; H. Wang; M. X. Wang; Y. Q. Wang; Z. T. Wang; W. W. Xiao; Z. G. Xiao; Y. F. Xie; L. H. Yao; L. Y. Yao; D. L. Yu; B. S. Yuan; K. J. Zhao; Y. Z. Zheng; G. W. Zhong; C. P. Zhou; J. Zhou; Y. Zhou; J. C. Yan; C. X. Yu; C. H. Pan; Yong Liu

2009-01-01

111

IPv6 Experimental Results Portend Operational Benefits for Military Systems  

Microsoft Academic Search

Transitioning military systems to the next generation Internet Protocol Version 6 (IPv6) is a large and complex problem. The use of experimentation and validation in laboratory and field demonstrations, and field exercises are the optimal ways to illustrate the operational improvements of the advanced features of IPv6. Through the participation in Joint Users Interoperability Communications Exercise 2006 (JUICE 06), Program

Thomas J. Walsh; Joyce S. Kerr; Ashok K. Jain

2007-01-01

112

Colon interposition for esophageal replacement: isoperistaltic or antiperistaltic? Experimental results  

Microsoft Academic Search

Background. Isoperistaltic colon is preferred to antiperistaltic colon for esophageal replacement, but experimental data do not exist to support this practice.Methods. In 7 dogs a 20 cm long colon loop was interposed between the skin and the small bowel, isoperistaltically in 3 dogs and antiperistaltically in 4 dogs. Three months later five strain-gauges were implanted and evacuation was investigated by

Bernhard Dreuw; Jürgen Fass; Svetlana Titkova; Michail Anurov; Michail Polivoda; Alexander P Öttinger; Volker Schumpelick

2001-01-01

113

First experimental results from the Valley Forge Radio Camera Program  

Microsoft Academic Search

An X-band high angular resolution imaging radar experiment using a broadly distributed antenna array has been conducted. The experimental resolving power is 5.2 x 10 to the 4th rad. Adaptive beam-forming is employed to compensate for the distortion in the aperture.

B. D. Steinberg; E. N. Powers; D. Carlson; B. Meagher Jr.; R. S. Berkowitz; C. N. Dorny; S. H. Seeleman

1979-01-01

114

First experimental results from the Valley Forge radio camera program  

Microsoft Academic Search

An X-band high angular resolution imaging radar experiment using a broadly distributed antenna array has been conducted. The experimental resolving power is 5.2 × 10-4rad. Adaptive beam-forming is employed to compensate for the distortion in the aperture.

B. D. Steinberg; E. N. Powers; D. Carlson; R. S. Berkowitz; C. N. Dorny; S. H. Seeleman

1979-01-01

115

Assignment of Uncertainties to the Results of Experimental Measurements.  

National Technical Information Service (NTIS)

After a brief review of some of the current ways of indicating in a quantitative manner the uncertainties which are associated with an experimental measurement, the main shortcomings of some of the usual practices are indicated. The present situation is u...

J. W. Mueller

1984-01-01

116

Interpretation of experimental results of spin chains with weak interchain interaction  

Microsoft Academic Search

Experimental results concerning magnetic susceptibility and heat capacity of the CuSb2O6 crystal, where the Cu2+ ions form chains interacting with strong short range antiferromagnetic (AF) intrachain and weak AF interchain interactions, can be interpreted in terms of small rings to which the large chains are split and rejoined. The weak interchain interaction causes a small energy gap between the ground

S. Thanos

2007-01-01

117

High phase order induction motors; part II-experimental results  

SciTech Connect

Experimental tests have been carried out on a small induction motor connected for six phases and for nine phases. These include torque measurements over the entire speed range and load tests with balanced source and with one phase open. Some of the machine impedances, including sequence impedances, were measured and these generally agree with predicted values. The motor was subjected to source voltages having harmonics and the measured currents show good agreement with theoretical values based on the analysis in a companion paper.

Klingshirn, E.A.

1983-01-01

118

Trust in Transitional Societies: Experimental Results from Russia  

Microsoft Academic Search

Abstract: To what extent do individuals trust one another in transitional societies? Does trust survive when political institutions are weak, when the potential for ethnic conflict is high and when old mechanisms,for social control have disappeared? This study uses a combination,of survey data and laboratory experimental methods,to investigate this question. The data are unique in that the experiments were conducted

Donna L. Bahry; Rick K. Wilson

119

Recent experimental results from a long-pulse J-band relativistic klystron amplifier developmental effort  

NASA Astrophysics Data System (ADS)

Recent experimental results, supporting simulations, and design modeling are presented from a developmental effort to produce a long pulse (approximately 1 microsecond(s) ) J-band (5.85 - 8.2 GHz) relativistic klystron amplifier (RKA) of the high current NRL genealogy. This RKA is designed to operate at approximately 6.6 GHz, with a desired rf output approximately 700 MW. Conversion of electron beam energy to microwave energy is obtained by a mock magnetically insulated coaxial converter which, in various incarnations, can be made to be either a cavity gap extractor or an inverse cathode.

Kato, Keith G.; Crouch, David D.; Sar, David R.; Speciale, Ross A.; Carlsten, Bruce E.; Fazio, Michael V.; Haynes, W. Brian; Stringfield, Ray M.

1994-05-01

120

Laser ablation of a turbid medium: Modeling and experimental results  

SciTech Connect

Q-switched Nd:YAG laser ablation of a turbid medium (paint) is studied. The optical properties (absorption coefficient, scattering coefficient, and its anisotropy) of a paint are determined with a multiple scattering model (three-flux model), and from measurements of reflection-transmission of light through thin layers. The energy deposition profiles are calculated at wavelengths of 532 nm and 1.064 {mu}m. They are different from those described by a Lambert-Beer law. In particular, the energy deposition of the laser beam is not maximum on the surface but at some depth inside the medium. The ablated rate was measured for the two wavelengths and compared with the energy deposition profile predicted by the model. This allows us to understand the evolution of the ablated depth with the wavelength: the more the scattering coefficient is higher, the more the ablated depth and the threshold fluence of ablation decrease.

Brygo, F.; Semerok, A.; Weulersse, J.-M.; Thro, P.-Y.; Oltra, R. [Commissariat a l'Energie Atomique, DEN/DANS/DPC/SCP/LILM, Batiment 467, 91191 Gifs/Yvette (France); LRRS-UMR 5613 CNRS, Universite de Bourgogne 21078 Dijon (France)

2006-08-01

121

Curcumin improves early functional results after experimental spinal cord injury  

Microsoft Academic Search

Background  Curcumin is a polyphenol extracted from the rhizome of Curcuma longa and well known as a multifunctional drug with anti-oxidative, anticancerous, and anti-inflammatory activities. The aim of\\u000a the study was to evaluate and compare the effects of the use of the curcumin and the methylprednisolone sodium succinate (MPSS)\\u000a functionally, biochemically, and pathologically after experimental spinal cord injury (SCI).\\u000a \\u000a \\u000a \\u000a \\u000a Method  Forty rats

Berker Cemil; Kivanc Topuz; Mehmet Nusret Demircan; Gokhan Kurt; Kagan Tun; Murat Kutlay; Osman Ipcioglu; Zafer Kucukodaci

2010-01-01

122

Experimental Studies of Ion Beam Neutralization: Preliminary Results  

NASA Astrophysics Data System (ADS)

A testing platform is designed to study ion beam neutralization in the mesothermal, collisionless region. In the experimental setup, argon neutrals were ionized in a microwave cavity and accelerated by a plasma lens system which was biased to 2500 V above the system ground. Electrons were boiled off from two hot tungsten filaments to neutralize the ion beam. The plasma is diagnosed using Langmuir probe and Faraday probe. A 3-D traversing system and a complete data acquisition loop were developed to efficiently measure 3-D beam profile. Preliminary measurements of beam profiles are presented for different operating conditions.

Ding, N.; Polansky, J.; Downey, R.; Wang, J.

2011-05-01

123

Optimal active vibration absorber: Design and experimental results  

NASA Astrophysics Data System (ADS)

An optimal active vibration absorber can provide guaranteed closed-loop stability and control for large flexible space structures with collocated sensors/actuators. The active vibration absorber is a second-order dynamic system which is designed to suppress any unwanted structural vibration. This can be designed with minimum knowledge of the controlled system. Two methods for optimizing the active vibration absorber parameters are illustrated: minimum resonant amplitude and frequency matched active controllers. The Controls-Structures Interaction Phase-1 Evolutionary Model at NASA LaRC is used to demonstrate the effectiveness of the active vibration absorber for vibration suppression. Performance is compared numerically and experimentally using acceleration feedback.

Lee-Glauser, Gina; Juang, Jer-Nan; Sulla, Jeffrey L.

1992-12-01

124

Experimental overview of Generalized Parton Distribution results from HERMES  

SciTech Connect

Over the course of more than a decade the HERMES experiment has accumulated a wealth of data with electron and positron beams on various gaseous targets from Hydrogen up to Xenon. In addition, the beams and targets can be polarized. This data set is viewed in the context of Generalized Parton Distributions, a theoretical formalism with an explicit three dimensional view of the structure of the nucleon. It provides a link between experimental observables and the total angular momentum of the quarks in the nucleon.

Zihlmann, B. [Jefferson Lab, 12000 Jefferson Avenue, Newport News, VA 23606 (United States)

2009-08-04

125

EXPERIMENTAL RESULTS OF INTEGRATED REFRIGERATION AND STORAGE SYSTEM TESTING  

Microsoft Academic Search

Launch operations engineers at the Kennedy Space Center have identified an Integrated Refrigeration and Storage system as a promising technology to reduce launch costs and enable advanced cryogenic operations. This system uses a closed cycle Brayton refrigerator to remove energy from the stored cryogenic propellant. This allows for control of the temperature and pressure of the fluid, and enables advanced

W. U. Notardonato; W. L. Johnson; J. Oliveira; K. Jumper

2010-01-01

126

Experimental Results of Integrated Refrigeration and Storage System Testing  

Microsoft Academic Search

Launch operations engineers at the Kennedy Space Center have identified an Integrated Refrigeration and Storage system as a promising technology to reduce launch costs and enable advanced cryogenic operations. This system uses a closed cycle Brayton refrigerator to remove energy from the stored cryogenic propellant. This allows for control of the temperature and pressure of the fluid, and enables advanced

W. U. Notardonato; W. L. Johnson; J. Oliveira; K. Jumper

2010-01-01

127

Flatband Electroreflectance of Gallium Arsenide. I. Experimental Results  

Microsoft Academic Search

The electroreflectance (ER) spectrum of n-type gallium arsenide in the 1. 2-5. 3-eV photon energy range has been measured. It was found from examination of the direct-edge Delta?1 line shapes and collaborative differential capacitance measurements that quite uniform fields were obtained. The interference between the light- and heavy-hole contributions to the ER signal at E0 was observed. The data were

Stephen F. Pond; Paul Handler

1972-01-01

128

NEG COATED CHAMBERS AT SOLEIL: TECHNOLOGICAL ISSUES AND EXPERIMENTAL RESULTS  

Microsoft Academic Search

The SOLEIL accelerator complex includes a 100 MeV LINAC pre-injector, a full energy booster synchrotron and a 2.75 GeV electron storage ring with a 354m circumference, which provides synchrotron light to 24 photon beam lines. SOLEIL is the first synchrotron facility specifically designed to make extensive use of Non Evaporable Getter (NEG) coating technology to improve the vacuum, reduce bremsstrahlung

C. Herbeaux; Synchrotron SOLEIL; A. Conte; P. Manini; A. Bonucci; S. Raimondi

129

Miniature underwater glider: Design, modeling, and experimental results  

Microsoft Academic Search

The concept of gliding robotic fish combines gliding and fin-actuation mechanisms to realize energy-efficient locomotion and high maneuverability, and holds strong promise for mobile sensing in versatile aquatic environments. In this paper we present the modeling and design of a miniature fish-like glider, a key enabling component for gliding robotic fish. The full dynamics of the glider is first derived

Feitian Zhang; John Thon; Cody Thon; Xiaobo Tan

2012-01-01

130

[Capacity for peripheral nerve regeneration. Experimental study--preliminary results].  

PubMed

Any injury affecting peripheral nerve continuity is followed by a degenerative reaction from nerve itself and its muscule. Nerve regeneration is possibly when the two ends are put in direct contact (direct suture), proximity (autologus or artificial grafts) or through muscle neurotization. The aim of this experimental study was to evaluate sciatic nerve degeneration and regeneration in rat after no suture (group 1), direct suture (group 2), nerve grafting (group 3) and muscle neurotization (group 4). Nerve samples were analyzed in optical microscopy at 8 and 16 weeks after surgery and nerve degeneration (group 1), axonal growth (group 2) and neuromuscular regeneration (group 4) were evaluated. Neuromuscular synapses after direct muscular neurotization are to be searched using the cholinesterase test. PMID:20509290

Per?ea, Mihaela; Lunc?, S

131

Guided wave modes in porous cylinders: Experimental results  

NASA Astrophysics Data System (ADS)

In this paper guided wave modes in porous media are investigated. A water-saturated porous cylinder is mounted in the test section of a shock tube. Between the porous sample and the wall of the shock tube a water-filled annulus exists. For very small annulus width, bulk waves are generated and one-dimensional modeling is sufficient. Otherwise two-dimensional effects become important and multiple guided wave modes occur. Using a newly developed traversable positioning system in the shock tube, the frequency-dependent phase velocities and damping coefficients in the 1-120 kHz frequency range were measured. Prony's method was used for data processing. Agreement was found between the experimental data and the two-dimensional modeling of the shock tube which was based on Biot's theory. copyright 2002 Acoustical Society of America.

Wisse, C. J.; Smeulders, D. M. J.; van Dongen, M. E. H.; Chao, G.

2002-09-01

132

Experimental study on a pendulum wave energy converter  

NASA Astrophysics Data System (ADS)

Many of the existing wave energy converters (WEC) are of oscillating water column (OWC) and point absorber (PA) types. Fewer references have been published in public on the pendulum type WEC. A series of experimental tests on a bottom-hinged pendulum WEC model are carried out and some results are revealed in the present study. The purpose of this paper is to present a detailed description of the tests. It is found that wave energy conversion efficiency varies with the applied damping and wave conditions. In addition, special attention is given to the effect of the water ballast on the efficiency of the wave energy converter. It is demonstrated that the ballast plays an important role in energy extraction. Better understanding on how the performance of the device is influenced by damping, wave height, wave period and ballast is shown.

Qiu, Shou-qiang; Ye, Jia-wei; Wang, Dong-jiao; Liang, Fu-lin

2013-06-01

133

Overview of experimental results on HL-2A  

NASA Astrophysics Data System (ADS)

Significant experimental advances have been made on the HL-2A tokamak along with substantial improvement and development of the hardware. A spontaneous particle transport barrier has been observed in Ohmic discharges without any external momentum input. The barrier was evidenced by a density perturbation study using modulated supersonic molecular beam injection (SMBI) and microwave reflectometry. The new features of the non-local transport effect induced with SMBI have been analysed. The three-dimensional spectral structures of the low frequency zonal flow, the geodesic acoustic mode (GAM) and the quasi-mode-like low frequency fluctuations have been observed simultaneously for the first time. In addition, the spectral structure of the density fluctuations of GAM was also identified. The e-fishbone instability excited by energetic electrons deviated from Maxwellian distribution has been investigated via a 10-channel CdTe hard x-ray detector. It was found that the e-fishbone was correlated with the existence of energetic electrons of 30-70 keV. The MHD experiment has indicated that the suppression of m/n = 2/1 tearing modes may be sustained by ECRH modulation at a frequency of about 10 Hz.

Duan, X. R.; Ding, X. T.; Dong, J. Q.; Yang, Q. W.; Yan, L. W.; Liu, Yi; Zou, X. L.; Liu, D. Q.; Xuan, W. M.; Chen, L. Y.; Rao, J.; Song, X. M.; Mao, W. C.; Wang, Q. M.; Cao, Z.; Li, B.; Cao, J. Y.; Lei, G. J.; Zhang, J. H.; Li, X. D.; Wang, S. J.; Liu, A. D.; Bu, M. N.; Chen, Y. H.; Chen, W.; Cheng, J.; Cui, C. H.; Cui, Z. Y.; Deng, Z. C.; Dong, Y. B.; Feng, B. B.; Gao, Q. D.; Han, X. Y.; Hong, W. Y.; Hu, H. T.; Huang, M.; Huang, Y.; Ji, X. Q.; Kang, Z. H.; Lan, T.; Li, G. S.; Li, H. J.; Li, Qing; Li, Qiang; Li, W.; Li, Y. G.; Li, Z. J.; Liu, Z. T.; Luo, C. W.; Mao, X. H.; Pan, Y. D.; Peng, J. F.; Shao, K.; Song, X. Y.; Sun, H. J.; Wang, A. K.; Wang, H.; Wang, M. X.; Wang, Y. Q.; Wang, Z. T.; Xiao, W. W.; Xiao, Z. G.; Xie, Y. F.; Yao, L. H.; Yao, L. Y.; Yu, D. L.; Yuan, B. S.; Zhao, K. J.; Zheng, Y. Z.; Zhong, G. W.; Zhou, C. P.; Zhou, J.; Zhou, Y.; Yan, J. C.; Yu, C. X.; Pan, C. H.; Liu, Yong

2009-10-01

134

Radio frequency perforation of cardiac tissue: modelling and experimental results.  

PubMed

Radio frequency (RF) current delivered through a thin catheter can be used to perforate the pulmonary valve or the atrial septum to treat pulmonary atresia in newborns. To understand better the mechanisms of RF perforation, a numerical model is developed, and experiments are performed in isolated canine cardiac tissue. The model consists of a cylindrical domain with a tissue layer between two blood layers. The finite-difference method is used to compute both the potential and temperature distributions. When the tissue temperature exceeds 100 degrees C in all points that are directly in front of the catheter, these points are considered to be instantly vaporised, and the catheter advances over these points. The computed temperature time course coincides with measured temperature at small voltages (< 16 V). Simulated perforation occurs when the voltage exceeds a threshold of 70-80 V for a catheter diameter of 0.30-0.44 mm, which coincides with experimental observations in the myocardium. A voltage exceeding this perforation threshold tends to decrease tissue damage. Shorter electrodes (0.7 mm as against 2.4 mm) with smaller diameters produce a more rapid perforation. In conclusion, numerical simulations provide insights into aspects of RF perforation, such as electrode size, current, speed of perforation and collateral damage. PMID:11094817

Shimko, N; Savard, P; Shah, K

2000-09-01

135

Modeling of rock friction 1. Experimental results and constitutive equations  

USGS Publications Warehouse

Direct shear experiments on ground surfaces of a granodiorite from Raymond, California, at normal stresses of ??6 MPa demonstrate that competing time, displacement, and velocity effects control rock friction. It is proposed that the strength of the population of points of contacts between sliding surfaces determines frictional strength and that the population of contacts changes continuously with displacements. Previous experiments demonstrate that the strength of the contacts increases with the age of the contacts. The present experiments establish that a characteristic displacement, proportional to surface roughness, is required to change the population of contacts. Hence during slip the average age of the points of contact and therefore frictional strength decrease as slip velocity increases. Displacement weakening and consequently the potential for unstable slip occur whenever displacement reduces the average age of the contacts. In addition to this velocity dependency, which arises from displacement dependency and time dependency, the experiments also show a competing but transient increase in friction whenever slip velocity increases. Creep of the sliding surface at stresses below that for steady state slip is also observed. Constitutive relationships are developed that permit quantitative simulation of the friction versus displacement data as a function of surface roughness and for different time and velocity histories. Unstable slip in experiments is controlled by these constitutive effects and by the stiffness of the experimental system. It is argued that analogous properties control earthquake instability. Copyright ?? 1979 by the American Geophysical Union.

Dieterich, J. H.

1979-01-01

136

EXPERIMENTAL RESULTS FROM A MICROWAVE CAVITY BEAM POSITION MONITOR.  

SciTech Connect

Future Linear Colliders have hard requirements for the beam transverse position stability in the accelerator. A beam Position Monitor (BPM) with the resolution better than 0.1 micron in the single bunch regime is needed to control the stability of the beam position along the linac. Proposed BPM is based on the measurement of the asymmetrical mode excited by single bunch in the cavity. Four stages of signal processing (space-, time-, frequency- and phase-filtering providing the required signal-to-noise ratio) are used to obtain extremely high resolution. The measurement set-up was designed by BINP and installed at ATF/BNL to test experimentally this concept. The set-up includes three two-coordinates BPM's at the frequency of 13.566 GHz, and reference intensity/phase cavity. BPM's were mounted on support table. The two-coordinates movers allow to move and align BPM's along the straight line, using the signals from the beam. The position of each monitor is controlled by the sensors with the accuracy 0.03 micron. The information from three monitors allows to exclude angle and position jitter of the beam and measure BPM resolution. In the experiments the resolution of about 0.15 micron for 0.25 nC beam intensity was obtained, that is close to the value required.

BALAKIN,V.; BAZHAN,A.; LUNEV,P.; SOLYAK,N.; VOGEL,V.; ZHOGOLEV,P.; LISITSYN,A.; YAKIMENKO,V.

1999-03-29

137

Experimental results and modeling of a dynamic hohlraum on SATURN  

SciTech Connect

Experiments were performed at SATURN, a high current z-pinch, to explore the feasibility of creating a hohlraum by imploding a tungsten wire array onto a low-density foam. Emission measurements in the 200--280 eV energy band were consistent with a 110--135 eV Planckian before the target shock heated, or stagnated, on-axis. Peak pinch radiation temperatures of nominally 160 eV were obtained. Measured early time x-ray emission histories and temperature estimates agree well with modeled performance in the 200--280 eV band using a 2D radiation magneto-hydrodynamics code. However, significant differences are observed in comparisons of the x-ray images and 2D simulations.

Derzon, M.S.; Allshouse, G.O.; Deeney, C.; Leeper, R.J.; Nash, T.J. [Sandia National Labs., Albuquerque, NM (United States); Matuska, W.; Peterson, D.L. [Los Alamos National Lab., NM (United States); MacFarlane, J.J. [Univ. of Wisconsin, Madison, WI (United States); Ryutov, D.D. [Lawrence Livermore National Lab., CA (United States)

1998-06-01

138

Experimental efforts and results in finding new heavy scintillators  

SciTech Connect

New heavy scintillators are being discovered with increasing frequency. In recent years NaI(Tl) (with its high light output and energy resolution) has been joined by BGO (with its high stopping power), BaF{sub 2} (with its excellent timing resolution), and CeF{sub 3} (with its speed and short Moliere radius). More than 10 potentially useful scintillators have been under development in the past five years, such as PbSO{sub 4} and Lu{sub 2}SiO{sub 5}(Ce). We tabulate the characteristics of these and other scintillators, including wavelength, luminous efficiency, decay time, and initial intensity. We describe a search strategy and the prospects for finding the ``ideal`` heavy scintillator, which would combine the light output of NaI(Tl) and CsI(Tl), the stopping power of BGO, and the speed of BaF{sub 2} and ZnO(Ga).

Derenzo, S.E.; Moses, W.W.

1992-09-01

139

Separation Control Using Lorentz Forces: Recent Experimental and Numerical Results  

NASA Astrophysics Data System (ADS)

The flow around bodies moving in weakly electrically conducting fluids can be controlled by applying electromagnetic forces originating from electrodes and permanent magnets suitably placed on the surface of the body. Here we consider the possibility of separation control for a two-dimensional bluff body and an inclined flat plate by inducing Lorentz forces parallel to the surface. We present physical and numerical experiments at diameter/chord Reynolds numbers in the range of 300--4,000 for the circular cylinder and 2,000--20,000 for the plate. Both steady and time-periodic forcing are applied. The physical experiments are conducted in an open channel with sodium hydroxide as the working fluid. Dramatic separation delays are observed on both bodies for a modest expenditure of energy. Special attention is drawn to lift enhancement due to separation delay for the inclined plate. Direct numerical simulations at low Reynolds numbers confirm the physical tendencies of the experiments.

Fey, Uwe; Weier, Tom; Gerbeth, Gunter; Mutschke, Gerd; Gad-El-Hak, Mohamed

1998-11-01

140

Effects of imperfect dynamic clamp: computational and experimental results.  

PubMed

In the dynamic clamp technique, a typically nonlinear feedback system delivers electrical current to an excitable cell that represents the actions of "virtual" ion channels (e.g., channels that are gated by local membrane potential or by electrical activity in neighboring biological or virtual neurons). Since the conception of this technique, there have been a number of different implementations of dynamic clamp systems, each with differing levels of flexibility and performance. Embedded hardware-based systems typically offer feedback that is very fast and precisely timed, but these systems are often expensive and sometimes inflexible. PC-based systems, on the other hand, allow the user to write software that defines an arbitrarily complex feedback system, but real-time performance in PC-based systems can be deteriorated by imperfect real-time performance. Here, we systematically evaluate the performance requirements for artificial dynamic clamp knock-in of transient sodium and delayed rectifier potassium conductances. Specifically, we examine the effects of controller time step duration, differential equation integration method, jitter (variability in time step), and latency (the time lag from reading inputs to updating outputs). Each of these control system flaws is artificially introduced in both simulated and real dynamic clamp experiments. We demonstrate that each of these errors affect dynamic clamp accuracy in a way that depends on the time constants and stiffness of the differential equations being solved. In simulations, time steps above 0.2ms lead to catastrophic alteration of spike shape, but the frequency-current relationship is much more robust. Latency (the part of the time step that occurs between measuring membrane potential and injecting re-calculated membrane current) is a crucial factor as well. Experimental data are substantially more sensitive to inaccuracies than simulated data. PMID:18076999

Bettencourt, Jonathan C; Lillis, Kyle P; Stupin, Laura R; White, John A

2007-10-24

141

Interpretation of experimental results of spin chains with weak interchain interaction  

NASA Astrophysics Data System (ADS)

Experimental results concerning magnetic susceptibility and heat capacity of the CuSb2O6 crystal, where the Cu ions form chains interacting with strong short range antiferromagnetic (AF) intrachain and weak AF interchain interactions, can be interpreted in terms of small rings to which the large chains are split and rejoined. The weak interchain interaction causes a small energy gap between the ground and the first excited states of CuSb2O6. The agreement between theory and experiment is remarkable. The fitting of the theoretical to the experimental results, permits the determination of the coupling constants of the Heisenberg Hamiltonian and the Lande factors along the symmetry axes of the crystal.

Thanos, S.

2007-05-01

142

Experimental results of harmonically oscillating flexible and rigid flat plates  

Microsoft Academic Search

The thrust produced by high aspect ratio oscillating flexible and rigid flat plates are measured using Particle Image Velocimetry over a range of Strouhal numbers in a the large water channel facility at New Mexico State University. Power input to the system was also measured. Results show that neutral\\/zero thrust is produced at a Strouhal number of 0.14 for all

Jeremy Pena; Scott Hightower; James Allen; Paulo Ferreira de Sousa; Banavara Shashikanth

2007-01-01

143

Aeolian Simulations: A Comparison of Numerical and Experimental Results  

Microsoft Academic Search

Aeolian processes are a major geomorphic agent on solid planetary bodies with atmospheres (Earth, Mars, Venus, and Titan). This paper describes preliminary efforts to model aeolian saltation using computational fluid dynamics (CFD) and to compare the results with those obtained in wind tunnel testing conducted in the Planetary Aeolian Laboratory at NASA Ames Research Center at ambient pressure. The end

O. Mathews; D. M. Burr; N. T. Bridges; J. E. Lyne; J. R. Marshall; R. Greeley; B. R. White; J. Hills; K. Smith; T. C. Prissel; J. F. Aliaga-Caro

2010-01-01

144

Delaminations in composite plates under transverse static loads - Experimental results  

NASA Astrophysics Data System (ADS)

Tests were performed measuring the damage initiation loads and the locations, shapes, and sizes of delaminations in Fiberite T300/976 graphite/epoxy, Fiberite IM7/977-2 graphite-toughened epoxy, and ICI APC-2 graphite-PEEK plates subjected to transverse static loads. The data were compared to the results of the Finn-Springer model, and good agreements were found between the measured and calculated delamination lengths and widths.

Finn, Scott R.; He, Yi-Fei; Springer, George S.

1992-11-01

145

Delaminations in composite plates under transverse impact loads - Experimental results  

NASA Astrophysics Data System (ADS)

Tests were performed measuring the locations and geometries of delaminations in Fiberite T300/976 graphite/epoxy, Fiberite IM7/977-2 graphite-toughened epoxy, and ICI APC-2 graphite/PEEK plates subjected to transverse impact loads. The data provide specific information on the effects of impactor velocity, impactor mass, material, thickness of back ply group, difference in fiber orientation between adjacent ply groups, plate thickness, and impactor nose radius. The data were compared to the results of the Finn-Springer model. The model was found to describe the data with reasonable accuracy.

Finn, Scott R.; He, Ye-Fei; Springer, George S.

146

Experimental results on heavy flavour hadro- and photo-production  

SciTech Connect

Results from experiments on the production of beauty and charm with hadron and photon beams are reviewed. Beauty production experiments are beginning to obtain b anti b cross-sections with hadron beams. Hadroproduction of charm is a somewhat more mature field, although high statistics are still eagerly sought. The situation is most promising with charm photoproduction experiments where total cross-sections, p/sub T//sup 2/ and X/sub F/ distributions and other production characteristics are now known in considerable detail.

Purohit, M.V.

1987-05-01

147

Experimental test accelerator: description and results of initial experiments  

SciTech Connect

The ETA is a high current (10,000 Amp) linear induction accelerator that produces short (30 ns) pulses of electrons at 5 MeV twice per second or in bursts of 5 pulses separated by as little as one millisecond. At this time the machine has operated at 65% of its design current and 90% of the design voltage. This report contains a description of the accelerator and its diagnostics; the results of the initial year of operation; a comparison of design codes with experiments on beam transport; and a discussion of some of the special problems and their status.

Fessenden, T.; Birx, D.; Briggs, R.

1980-06-02

148

Experimental Results of Guided Wave Travel Time Tomography  

NASA Astrophysics Data System (ADS)

Corrosion is one of the industries major issues regarding the integrity of assets. Currently inspections are conducted at regular intervals to ensure a sufficient integrity level of these assets. Cost reduction while maintaining a high level of reliability and safety of installations is a major challenge. The concept of predictive maintenance using permanent sensors that monitor the integrity of an installation matches very well with the objective to reduce cost while maintaining a high safety level. Guided waves are very attractive for permanent monitoring systems because they can travel over large distances and therefore provide the essential large area coverage. Making use of the dispersive behavior of the guided waves, a wall thickness map over a distance of several meters can be made using only two rings of guided wave transducers. Travel time tomography is used to translate transmission travel times into a wall thickness map. This method has been applied in the field for the first time to map the wall thickness under two clearly corroded pipe supports of a 8'' and 10'' gas pipe line. The tomographic inversion results clearly maps the corrosion under the supports. Independent reference measurements confirm the tomographic inversion results.

Volker, Arno; Bloom, Joost

2011-06-01

149

PERSEE: experimental results on the cophased nulling bench  

NASA Astrophysics Data System (ADS)

Nulling interferometry is still a promising method to characterize spectra of exoplanets. One of the main issues is to cophase at a nanometric level each arm despite satellite disturbances. The bench PERSEE aims to prove the feasibility of that technique for spaceborne missions. After a short description of PERSEE, we will first present the results obtained in a simplified configuration: we have cophased down to 0.22 nm rms in optical path difference (OPD) and 60 mas rms in tip/tilt, and have obtained a monochromatic null of 3 · 10-5 stabilized at 3•10-6. The goal of 1 nm with additional typical satellite disturbances requires the use of an optimal control law; that is why we elaborated a dedicated Kalman filter. Simulations and experiments show a good rejection of disturbances. Performance of the bench should be enhanced by using a Kalman control law, and we should be able to reach the desired nanometric stability. Following, we will present the first results of the final polychromatic configuration, which includes an achromatic phase shifter, perturbators and optical delay lines. As a conclusion, we give the first more general lessons we have already learned from this experiment, both at system and component levels for a future space mission.

Lozi, J.; Cassaing, F.; Le Duigou, J. M.; Houairi, K.; Sorrente, B.; Montri, J.; Jacquinod, S.; Rees, J.-M.; Pham, L.; Lhome, E.; Buey, T.; Hénault, F.; Marcotto, A.; Girard, P.; Mauclert, N.; Barillot, M.; Coudé du Foresto, V.; Ollivier, M.

2010-07-01

150

Conformal external radiotherapy of prostatic carcinoma: requirements and experimental results.  

PubMed

The aim of conformal radiotherapy is to deliver, with high precision, a specific dose (which may be a high dose) to a planning target volume, concurrently with irradiating as little as possible healthy tissue and organs at risk. Radiation therapy may suffer from a number of problems that result in both over- or under-sizing the irradiation fields, making over-rough simplifications of the irradiation ballistics and delivering an insufficient tumoral dose (to spare critical organs and reduce toxicity). One of these problems lies in the accurate positioning of the planning target volume with respect to the irradiation system, thence in the correct execution of the ballistics. In this paper, we describe a system aiming at achieving a higher overall accuracy in the delivery of prostatic boost for carcinoma of the prostate. The system is based on the use of ultrasonic images for measuring the actual position of the prostate just before irradiation. Since these images are registered with pre-operative (CT or MR) images, the position and orientation of the planning target volume is computed with respect to the irradiation system, and can be corrected accordingly. First experiments have been performed on dummies, and the results are discussed. PMID:8310143

Troccaz, J; Menguy, Y; Bolla, M; Cinquin, P; Vassal, P; Laieb, N; Desbat, L; Dusserre, A; Dal Soglio, S

1993-11-01

151

New experimental results in atlas-based brain morphometry  

NASA Astrophysics Data System (ADS)

In a previous meeting, we described a computational approach to MRI morphometry, in which a spatial warp mapping a reference or atlas image into anatomic alignment with the subject is first inferred. Shape differences with respect to the atlas are then studied by calculating the pointwise Jacobian determinant for the warp, which provides a measure of the change in differential volume about a point in the reference as it transforms to its corresponding position in the subject. In this paper, the method is used to analyze sex differences in the shape and size of the corpus callosum in an ongoing study of a large population of normal controls. The preliminary results of the current analysis support findings in the literature that have observed the splenium to be larger in females than in males.

Gee, James C.; Fabella, Brian A.; Fernandes, Siddharth E.; Turetsky, Bruce I.; Gur, Ruben C.; Gur, Raquel E.

1999-05-01

152

Experimental Results on Statistical Approaches to Page Replacement Policies  

SciTech Connect

This paper investigates the questions of what statistical information about a memory request sequence is useful to have in making page replacement decisions: Our starting point is the Markov Request Model for page request sequences. Although the utility of modeling page request sequences by the Markov model has been recently put into doubt, we find that two previously suggested algorithms (Maximum Hitting Time and Dominating Distribution) which are based on the Markov model work well on the trace data used in this study. Interestingly, both of these algorithms perform equally well despite the fact that the theoretical results for these two algorithms differ dramatically. We then develop succinct characteristics of memory access patterns in an attempt to approximate the simpler of the two algorithms. Finally, we investigate how to collect these characteristics in an online manner in order to have a purely online algorithm.

LEUNG,VITUS J.; IRANI,SANDY

2000-12-08

153

Ablative Richtmyer-Meshkov Instability: Theory and Experimental Results  

SciTech Connect

Rayleigh–Taylor instability, the main source of symmetry degradation in ICF experiments, is seeded at the early stage of an implosion, during the shock transit through the shell. The ablation-front nonuniformities at such a time can be amplified by an instability, which is similar to the Richtmyer–Meshkov instability. In the presence of ablation, however, the dynamic overpressure (rocket effect) significantly reduces the perturbation growth. The modes localized inside the conduction zone between the laser-absorption region and the ablation front are totally stabilized. An analytical model is presented to describe the perturbation evolution at the ablation front during the shock propagation time. The model is compared against the results of both the multidimensional simulations and a series of experiments performed on the OMEGA Laser System.

Goncharov, V.N.; Gotchev, O.V.; McCrory, R.L.; McKenty, P.W.; Meyerhofer, D.D.; Sangster, T.C.; Skupsky, S.; Cherfils-Clerouin, C.

2006-06-28

154

Wide-field Fizeau imaging telescope: experimental results  

NASA Astrophysics Data System (ADS)

A nine-aperture, wide-field Fizeau imaging telescope has been built at the Lockheed-Martin Advanced Technology Center. The telescope consists of nine, 125 mm diameter collector telescopes coherently phased and combined to form a diffraction-limited image with a resolution that is consistent with the 610 mm diameter of the telescope. The phased field of view of the array is 1 ?rad. The measured rms wavefront error is 0.08 waves rms at 635 nm. The telescope is actively controlled to correct for tilt and phasing errors. The control sensing technique is the method known as phase diversity, which extracts wavefront information from a pair of focused and defocused images. The optical design of the telescope and typical performance results are described.

Kendrick, R. L.; Aubrun, Jean-Noel; Bell, Ray; Benson, Robert; Benson, Larry; Brace, David; Breakwell, John; Burriesci, Larry; Byler, Eric; Camp, John; Cross, Gene; Cuneo, Peter; Dean, Peter; Digumerthi, Ramji; Duncan, Alan; Farley, John; Green, Andy; Hamilton, Howard H.; Herman, Bruce; Lauraitis, Kris; de Leon, Erich; Lorell, Kenneth; Martin, Rob; Matosian, Ken; Muench, Tom; Ni, Mel; Palmer, Alice; Roseman, Dennis; Russell, Sheldon; Schweiger, Paul; Sigler, Rob; Smith, John; Stone, Richard; Stubbs, David; Swietek, Gregg; Thatcher, John; Tischhauser, C.; Wong, Harvey; Zarifis, Vassilis; Gleichman, Kurt; Paxman, Rick

2006-06-01

155

Numerical Simulation of Micronozzles with Comparison to Experimental Results  

NASA Astrophysics Data System (ADS)

A numerical analysis of conical micronozzle flows has been conducted using the commercial software package CFD-RC FASTRAN [13]. The numerical results have been validated by comparison with direct thrust and mass flow measurements recently performed in ESTEC Propulsion Laboratory on Polyflex Space Ltd. 10mN Cold-Gas thrusters in the frame of ESA CryoSat mission. The flow is viscous dominated, with a throat Reynolds number of 5000, and the relatively large length of the nozzle causes boundary layer effects larger than usual for nozzles of this size. This paper discusses in detail the flow physics such as boundary layer growth and structure, and the effects of rarefaction. Furthermore a number of different domain sizes and exit boundary conditions are used to determine the optimum combination of computational time and accuracy.

Thornber, B.; Chesta, E.; Gloth, O.; Brandt, R.; Schwane, R.; Perigo, D.; Smith, P.

2004-10-01

156

Identifier mapping performance for integrating transcriptomics and proteomics experimental results  

PubMed Central

Background Studies integrating transcriptomic data with proteomic data can illuminate the proteome more clearly than either separately. Integromic studies can deepen understanding of the dynamic complex regulatory relationship between the transcriptome and the proteome. Integrating these data dictates a reliable mapping between the identifier nomenclature resultant from the two high-throughput platforms. However, this kind of analysis is well known to be hampered by lack of standardization of identifier nomenclature among proteins, genes, and microarray probe sets. Therefore data integration may also play a role in critiquing the fallible gene identifications that both platforms emit. Results We compared three freely available internet-based identifier mapping resources for mapping UniProt accessions (ACCs) to Affymetrix probesets identifications (IDs): DAVID, EnVision, and NetAffx. Liquid chromatography-tandem mass spectrometry analyses of 91 endometrial cancer and 7 noncancer samples generated 11,879 distinct ACCs. For each ACC, we compared the retrieval sets of probeset IDs from each mapping resource. We confirmed a high level of discrepancy among the mapping resources. On the same samples, mRNA expression was available. Therefore, to evaluate the quality of each ACC-to-probeset match, we calculated proteome-transcriptome correlations, and compared the resources presuming that better mapping of identifiers should generate a higher proportion of mapped pairs with strong inter-platform correlations. A mixture model for the correlations fitted well and supported regression analysis, providing a window into the performance of the mapping resources. The resources have added and dropped matches over two years, but their overall performance has not changed. Conclusions The methods presented here serve to achieve concrete context-specific insight, to support well-informed decisions in choosing an ID mapping strategy for "omic" data merging.

2011-01-01

157

[Arrest of spermatogenesis by various antibiotics: preliminary experimental results].  

PubMed

9 antibiotics used in urology were injected for 8 days into male rats, and their effects observed on testicular histochemistry and histology. The antibiotics were: spiramycin 25 mg/kg, N-(5-nitro-furfurylidene)-1-amino 2 mg/kg, gentamycin sulfate 1.2 mg/kg, sodium chloramphenicol succinate 30 mg/kg, colimycin methane sulfonate 20,000 U/kg, framycetin sulfate 10 mg/kg, 7-(thiophene-2-acetamido-cephalosporanate sodium 30 mg/kg, crystalline potassium penicillin G 40,000 U/kg and oxytetracycline 10 mg/kg (injection routes not specified). The results were classified into 3 categories: first, gentamycin nitrofurfurlidine-aminohydantoine and oxytetracycline arrested cell division in spermatogonia and partially or totally blocked meiosis in primary spermatocytes. The Feulgen reaction (a stain for DNA) was faint in the germinal epithelium. In the second category were spiramycin, thiophene-acetamido-cephalosporanate, colimycin and framycetin, which inhibited mitosis in spermatogonia, therefore permitting few primary spermatocytes to reach metaphase. In the third group were penicillin G and chloramphenicol which partly or completely blocked mitotsis in spermatogonia. In all cases interstitial capillaries were congested. The severity of effect was least with penic illin, moderate with oxytetracycline, and generalized and severe with the others. Histochemical stains showed strong activity of glucose-6-phosphate and isocitric dehydrogenase in the interstitial cells, and in the spermatogonia, but lower than normal in the spermatids and spermatozoa. Glutamate dehydrogenase was low in spermatogonia and primary spermatocytes. Classification of these antibiotics according to these results did not resemble any known chemical or antibacterial class ification. PMID:5515390

Dokov, V K; Timmermans, L

1970-07-01

158

Experimental results: Pilot plant calcine dissolution and liquid feed stability  

SciTech Connect

The dissolution of simulated Idaho Chemical Processing Plant pilot plant calcines, containing none of the radioactive actinides, lanthanides or fission products, was examined to evaluate the solubility of calcine matrix materials in acidic media. This study was a necessary precursor to dissolution and optimization experiments with actual radionuclide-containing calcines. The importance of temperature, nitric acid concentration, ratio of acid volume to calcine mass, and time on the amount, as a weight percentage of calcine dissolved, was evaluated. These parameters were studied for several representative pilot plant calcine types: (1) Run No. 74 Zirconia calcine; (2) Run No. 17 Zirconia/Sodium calcine; (3) Run No. 64 Zirconia/Sodium calcine; (3) Run No. 1027 Alumina calcine; and (4) Run No. 20 Alumina/Zirconia/Sodium calcine. Statistically designed experiments with the different pilot plant calcines indicated the effect of the studied process variables on the amount of calcine dissolved decreases in the order: Acid/Calcine Ratio > Temperature > HNO{sub 3} Concentration > Dissolution Time. The following conditions are suitable to achieve greater than 90 wt. % dissolution of most Zr, Al, or Na blend calcines: (1) Maximum nitric acid concentration of 5M; (2) Minimum acid/calcine ratio of 10 mL acid/1 gram calcine; (3) Minimum dissolution temperature of 90{degrees}C; and (4) Minimum dissolution time of 30 minutes. The formation of calcium sulphate (CaSO{sub 4}) precipitates was observed in certain dissolved calcine solutions during the dissolution experiments. Consequently, a study was initiated to evaluate if and under what conditions the resulting dissolved calcine solutions would be unstable with regards to precipitate formation. The results indicate that precipitate formation in the calcine solutions prepared under the above proposed dissolution conditions are not anticipated.

Herbst, R.S.; Fryer, D.S.; Brewer, K.N.; Johnson, C.K.; Todd, T.A.

1995-02-01

159

Non-Shock Initiation of the Plastic Bonded Explosive PBXN-5: Experimental Results  

NASA Astrophysics Data System (ADS)

The plastic bonded explosive PBXN-5 was studied under impulsive loading experiments to relate impact-induced mechanical damage to the onset of, and the extent of reaction produced. A small diameter projectile generated shock and release conditions at the impact interface, on the microsecond time scale during the initial portion of the impulsive loading. These shock and release wave interactions generate significant damage, resulting in a porous, powder compaction-type initiation behavior. Experimental measurements show an energy threshold for initiation of reaction which relates to impact-induced kinetic energy. These results are implemented in the model development and validation phases of the damage-induced reaction (DMGIR) model, which is used to simulate impact scenarios of explosives, explosive components, and explosive systems.

Lappo, K. N.; Todd, S. N.; Anderson, M. U.; Vogler, T. J.

2007-12-01

160

The experimental results and analysis of a borehole radar prototype  

NASA Astrophysics Data System (ADS)

A prototype of borehole radar has been successfully tested in three sites for different purposes under a field condition. The objective of the prototype is providing an effective down-hole tool for detecting targets in deep boreholes situated in a relatively high conductivity area such as the metal ores. The first testing site is at a geothermal field. The fractures extending more than 20 m from the borehole are delineated by the borehole radar in the single-hole reflection mode. The second testing site is located in a jade mine for basement evaluation. The cross-hole measurement mode was used to detect the cavities made by previous unorganized mining activities. Several high-velocity anomalies were found in the velocity profile and presumably the targets of the mine shafts and tunnels. The third test site is located in a mineralized belt characterized by low resistivity less than 1000 Ohm m, the surface-borehole measurement was carried out and the data were processed with velocity tomography. The low-velocity zone corresponds to a mineralized zone from geological records. The three testing results proved the readiness of this borehole radar prototype for further deployment in more complicated and realistic field situations.

Liu, Sixin; Wu, Junjun; Dong, Hang; Fu, Lei; Wang, Fei

2012-04-01

161

Bridge Testing With Ground-Based Interferometric Radar: Experimental Results  

NASA Astrophysics Data System (ADS)

The research of innovative non-contact techniques aimed at the vibration measurement of civil engineering structures (also for damage detection and structural health monitoring) is continuously directed to the optimization of measures and methods. Ground-Based Radar Interferometry (GBRI) represents the more recent technique available for static and dynamic control of structures and ground movements. Dynamic testing of bridges and buildings in operational conditions are currently performed: (a) to assess the conformity of the structure to the project design at the end of construction; (b) to identify the modal parameters (i.e. natural frequencies, mode shapes and damping ratios) and to check the variation of any modal parameters over the years; (c) to evaluate the amplitude of the structural response to special load conditions (i.e. strong winds, earthquakes, heavy railway or roadway loads). If such tests are carried out by using a non-contact technique (like GBRI), the classical issues of contact sensors (like accelerometers) are easily overtaken. This paper presents and discusses the results of various tests carried out on full-scale bridges by using a Stepped Frequency-Continuous Wave radar system.

Chiara, P.; Morelli, A.

2010-05-01

162

Experimental Results on Electrorheology of Liquid Crystalline Polymer Solutions  

NASA Astrophysics Data System (ADS)

The electrorheological (ER) effect is known as the enhancement of the apparent viscosity upon application of an external electric field. Suspensions of polarizable particles in non-conducting solvents are the most studied electrorheological fluids, however, liquid crystalline materials may also present ER effect as long as their dielectric anisotropy is positive. In the liquid crystalline state of a positive dielectric anisotropy, the application of the electric field makes the director align perpendicular to the flow direction, thus increasing the apparent viscosity. In this work results of two liquid crystalline polymer solutions, acetoxypropylcellulose (APC) in dimethylacetamide (DMAc) and poly-?-benzyl-L-glutamate (PBLG) in 1,4-dioxane, presenting opposite behavior upon application of the electric field, will be presented. APC/DMAc (negative dielectric anisotropy) presents a decrease of the apparent viscosity upon application of the electric field, as expected, while PBLG/1,4-dioxane (positive dielectric anisotropy) presents the opposite behavior. For this last solution we will present the shear flow curves for different electric fields in function of polymer molecular weight and solution concentration.

Neves, S.; Leal, C. R.; Cidade, M. T.

2008-07-01

163

Micromachined photonic integrated circuits for sensor applications: experimental results  

NASA Astrophysics Data System (ADS)

The paper presents the integration ont he same chip of: Mach-Zehnder interferometers and Y junctions based on SiON waveguides, 3D movable micromechanical structures, optical couplers and photodetectors for optical read-out. The SiON low loss optical waveguides were fabricated by LPCVD processes, compatible with CMOS technology. The diaphragms, used for pressure sensing, obtained by p+ etch stop techniques, were placed under the sensing arm of the interferometer. The cantilevers, used in micromechanical resonators were manufactured by front side micromachining. The optical waveguides were coupled with different types of photodetectors, for optical read-out. Also experiments for hybrid integration of an emitting device have been performed. We used an AlGaAs emitting diode, with high edge emission, mounted in a silicon groove, on the same wafer with the sensor. The lateral emitted light is coupled in the waveguide. One of the main problems that had to be solved will be the matching of all the involved technologies. The result of our research is the demonstration of the compatibility between the technological process involved and the possibility of integration on the same silicon substrate of different components: waveguides, photodiodes, emitting devices, 3D movable microstructures in order to realize intelligent microsensors.

Cristea, Dana; Muller, Raluca; Pavelescu, Ioan

1999-03-01

164

EXPERIMENTAL RESULTS OF THE NEPHELINE PHASE III STUDY  

SciTech Connect

This study is the third phase in a series of experiments designed to reduce conservatism in the model that predicts the formation of nepheline, a crystalline phase that can reduce the durability of high level waste glass. A Phase I study developed a series of glass compositions that were very durable while their nepheline discriminator values were well below the current nepheline discriminator limit of 0.62, where nepheline is predicted to crystallize upon slow cooling. A Phase II study selected glass compositions to identify any linear effects of composition on nepheline crystallization and that were restricted to regions that fell within the validation ranges of the Defense Waste Processing Facility (DWPF) Product Composition Control System (PCCS) models. However, it was not possible to identify any linear effects of composition on chemical durability performance for this set of study glasses. The results of the Phase II study alone were not sufficient to recommend modification of the current nepheline discriminator. It was recommended that the next series of experiments continue to focus not only on compositional regions where the PCCS models are considered applicable (i.e., the model validation ranges), but also be restricted to compositional regions where the only constraint limiting processing is the current nepheline discriminator. Two methods were used in selecting glasses for this Phase III nepheline study. The first was based on the relationship of the current nepheline discriminator model to the other DWPF PCCS models, and the second was based on theory of crystallization in mineral and glass melts. A series of 29 test glass compositions was selected for this study using a combination of the two approaches. The glasses were fabricated and characterized in the laboratory. After reviewing the data, the study glasses generally met the target compositions with little issue. Product Consistency Test results correlated well with the crystallization analyses in that those glasses that were found to contain nepheline after the centerline canister cooled (ccc) heat treatment generally had normalized release values that were greater than their quenched counterparts on a statistically significant basis. The current nepheline discriminator as implemented at the DWPF was shown to continue to work well in predicting nepheline prone glass compositions. A main objective of this study was to identify any compositional regions where conservatism in the current nepheline discriminator was preventing access to those regions that would otherwise be acceptable for DWPF processing by the PCCS models. Four glasses (based on the measured compositions) were identified through this study that met those criteria. However, a review of the individual compositions of these glasses revealed no clear trends that might indicate a driver for suppression of nepheline. Another objective of this study was to evaluate an alternative nepheline discriminator model developed using theory of crystallization in mineral and glass melts. Unfortunately this new model, in its current state, was unsuccessful in predicting nepheline crystallization in the glass compositions selected for this study. It is recommended that the data collected in this study be incorporated into the new model for further refinement.

Fox, K.; Edwards, T.

2009-11-09

165

Comparison of simulation and experimental results for rf thermal treatment devices with or without cooling  

NASA Astrophysics Data System (ADS)

Thermal treatment to avoid a surgical procedure involves a variety of energy sources. In several sites, radiofrequency energy is used as a source of thermal treatment. In the course of controlling lesion volume and shape during therapy, a number of sizes and shapes of applicators can be used as well as cooling or power pulsing to control or increase lesion size. Multiple sources are also used with monopolar or sesquipolar radiofrequency power delivery to enlarge the treatment volume. Following extensive in-vitro and in-vivo testing to optimize lesion size with time, power, and device, a simulation was set up to correlate theoretical predictions with experimental results with and without blood flow. A finite element model was applied to simulate the electric field and by using the bioheat equation, a thermal profile over time was established for various device parameters used in the experiments. The damage integral was used to estimate lesion size of irreversible damage. These results were compared to experimental results to verify the model's accuracy in predicting lesion size of both in-vitro and in-vivo experiments.

Ryan, Thomas P.; Goldberg, S. Nahum

1999-05-01

166

Experimental investigation of spark discharge energy  

NASA Astrophysics Data System (ADS)

Minimum ignition energy is one of the important characteristics for electrostatic sensitivity of explosives and determination of the spark discharge energy is necessary for decision making of explosion prevention. In this paper, the real spark discharge energy was determined by the integration of the measured voltage and discharge current in a needle-to-plate configuration. The influence of the charging voltage and polarity, the charging capacitance and the electrode gap on the spark discharge energy was investigated. It is shown that the energy deposited into the discharge system is always smaller than that stored in the charging capacitor, especially at lower voltages that the discharge shows one current pulse and the energy efficiency is less than 30%. The discharge becomes complete at higher voltages when the discharge shows double pulses and the energy efficiency is close to 100%. For given charging capacitance and voltage, the real discharge energy is determined by the discharge mode rather than the electrode gap or the voltage polarity.

Peng, Zulin; Zhang, Yu; Chen, Dongjie; Miao, Jinsong; Ouyang, Jiting

2013-03-01

167

The energy behind Vernon Smith's experimental economics  

Microsoft Academic Search

This paper begins with the interplay of the induced value theory and the Hayek hypothesis, and subsequently suggests that we need to understand Vernon Smith's experimental method as not simply empirical, but encompassing a commitment to a special version of neoclassical demand theory. To this end, we compare his commitment to Harold Hotelling's important work on demand, an exemplar of

Kyu Sang Lee; Philip Mirowski

2008-01-01

168

Performance analysis of experimental device of travelling wave direct energy converter  

Microsoft Academic Search

Numerical analyses with the one-dimensional approximation have been carried out for a small-scale experimental device of TWDEC. The following results have been obtained. Numerical results agree well with experimental results on the conversion efficiency and the energy distribution when the phase difference between voltages of the modulator and the decelerator is the same as the experiment. It has been found

M. Ishikawa; K. Horita; Y. Yasaka; T. Takeno; Y. Tomita

2006-01-01

169

Etude de l'endommagement de cibles metalliques par des ions de forte energie: le cas du fer, resultats experimentaux et simulations numeriques. (Damage induced by swift heavy ions in a pure metallic target: iron. Experimental results and numerical simulation).  

National Technical Information Service (NTIS)

The damage induced when a high energy deposition occurs in the electronic system of a pure metal (Ag, Co, Fe, Ni, Pd, Pt, Ti, W, Zr) has been investigated using two methods: low temperature swift heavy ion (O, Ar, Kr, Xe, Pb, u) irradiations and computer ...

P. Legrand

1993-01-01

170

Monte Carlo calculations and experimental results of Bonner spheres systems with a new cylindrical Helium3 proportional counter  

Microsoft Academic Search

The experimental results on neutron energy spectra, integral fluences and equivalent dose measurements performed by means of a Bonner sphere system placed inside the containment building of the Vandellòs II Nuclear Power Plant (Tarragona, Spain) are presented. The equivalent dose results obtained with this system are compared to those measured with different neutron area detectors (Berthold, Dineutron, Harwell). A realistic

H. Muller; F. Fernández; L Van Ryckeghem; P. Alexandre; T. Bouassoule; J.-L Pochat; M. Tomas

2002-01-01

171

The effect of ambient pressure on well chamber response: experimental results with empirical correction factors.  

PubMed

For some air-communicating well-type chambers used for low-energy brachytherapy source assay, deviations from expected values of measured air kerma strength were observed at low pressures associated with high altitudes. This effect is consistent with an overcompensation by the air density correction to standard atmospheric temperature and pressure (P(TP)). This work demonstrates that the P(TP) correction does not fully compensate for the high altitude pressure effects that are seen with air-communicating chambers at low photon energies in the range of 20-100 keV. Deviations of up to 18% at a pressure corresponding to an approximate elevation of 8500 ft for photon energies of 20 keV are possible. For high-energy photons and for high-energy beta emitters in air-communicating chambers the P(TP) factor is applicable. As expected, the ambient pressure does not significantly affect the response of pressurized well chambers (within 1%) to either low- or high-energy photons. However, when used with beta emitters, pressurized chambers appear to exhibit a slight dependence on the ambient pressure. Using measured data, the response and correction factors were determined for three models of air-communicating well chambers for low-energy photon sources at various pressures corresponding to elevations above sea level. Monte Carlo calculations were also performed which were correlated with the experimental findings. A more complete study of the Monte Carlo calculations is presented in the accompanying paper, "The effect of ambient pressure on well chamber response: Monte Carlo calculated results for the HDR1000 Plus." PMID:15839341

Griffin, S L; DeWerd, L A; Micka, J A; Bohm, T D

2005-03-01

172

Experimental quantification of inverse energy cascade in deep rotating turbulence  

NASA Astrophysics Data System (ADS)

We experimentally study the characteristics of an inverse energy cascade in deep rotating turbulence. Experiments were performed in a rotating cylindrical water tank with energy injection at a small scale. The steady state energy spectrum of the horizontal velocity field at scales larger than the injection scale is very well described by the 2D inverse energy cascade spectrum. Transient energy spectra evolve via 2D-like inverse cascade, with energy transfer from small to large scales. The measured energy transfer rates are in good quantitative agreement with the predictions for 2D turbulence.

Yarom, Ehud; Vardi, Yuval; Sharon, Eran

2013-08-01

173

The coefficient of restitution of ice particles in glancing collisions: Experimental results for unfrosted surfaces  

NASA Astrophysics Data System (ADS)

Both Saturn's rings and planetesimal disks are made up of particles in Keplerian orbits. Inelastic collisions between these particles regulate their dynamical evolution and possible aggregation. We present an experiment to simulate glancing collisions in Saturn's rings and in planetesimal disks and thus measure contributions to the energy loss for both normal and tangential velocity components. In this experiment, a spherical iceball mounted on a long-period, two dimensional pendulum is made to impact a flat ice surface in a low-temperature environment. This paper describes the experimental apparatus in detail and presents results for smooth unfrosted surfaces. The energy loss for tangential motion is suprisingly low, indicating that very little friction is present at low impact speeds for relatively smooth ice surfaces and temperatures near 100 K. We have also investigated room-temperature collisions of a rubber ball on a rough surface to understand the energy loss in situations where the tangential friction force is not small. In this analogous case, the energy loss is maximum for impact angles in the range 45 deg-60 deg.

Supulver, Kimberley D.; Bridges, Frank G.; Lin, D. N. C.

1995-01-01

174

Mathematics of complexity in experimental high energy physics  

NASA Astrophysics Data System (ADS)

Mathematical ideas and approaches common in complexity-related fields have been fruitfully applied in experimental high energy physics also. We briefly review some of the cross-pollination that is occurring.

Eggers, H. C.

2004-07-01

175

Solar micro-energy harvesting based on thermoelectric and latent heat effects. Part II: Experimental analysis  

Microsoft Academic Search

This study investigates, experimentally, the use of thermoelectric generators with phase change materials (PCM) to harvest micro-renewable energy. Experimental results in the laboratory and in real loading conditions show that the coupled effects of heat flux (solar radiation), external temperature and convection (wind) significantly influence the micro-energy harvest. Unlike other approaches, the proposed system is able to produce micro-energy by

Qi Zhang; Amen Agbossou; Zhihua Feng; Mathieu Cosnier

2010-01-01

176

Some experimental data for thermal pile energy storage  

Microsoft Academic Search

A description is presented of a theoretical analysis and an experimental investigation regarding the possibility to use rocks for thermal storage applications in connection with the utilization of solar energy. The theoretical analysis reported is concerned with the mathematical relations governing the flow of air through packed beds. In the experimental investigation a number of materials were tested separately concerning

A. A. M. Sayigh; M. R. Shaalan

1978-01-01

177

Experimental evidence of transient growth of energy before airfoil flutter  

Microsoft Academic Search

This paper presents an experimental evidence of the transient growth of energy for the coupled-mode flutter of an airfoil. The phenomenon occurs even in linearly stable dynamical systems. Its application is rather new in the context of fluid-structure interactions where only theoretical and numerical studies of transient growth exist. The experimental setup allows a NACA 0015 airfoil to oscillate in

P. Hémon; E. de Langre; P. Schmid

178

Femtosecond laser for glaucoma treatment: the comparison between simulation and experimentation results on ocular tissue removal  

NASA Astrophysics Data System (ADS)

In ophthalmology, the use of femtosecond lasers is receiving more attention than ever due to its extremely high intensity and ultra short pulse duration. It opens the highly beneficial possibilities for minimized side effects during surgery process, and one of the specific areas is laser surgery in glaucoma treatment. However, the sophisticated femtosecond laser-ocular tissue interaction mechanism hampers the clinical application of femtosecond laser to treat glaucoma. The potential contribution in this work lies in the fact, that this is the first time a modified moving breakdown theory is applied, which is appropriate for femtosecond time scale, to analyze femtosecond laser-ocular tissue interaction mechanism. Based on this theory, energy deposition and corresponding thermal increase are studied by both simulation and experimentation. A simulation model was developed using Matlab software, and the simulation result was validated through in-vitro laser-tissue interaction experiment using pig iris. By comparing the theoretical and experimental results, it is shown that femtosecond laser can obtain determined ocular tissue removal, and the thermal damage is evidently reduced. This result provides a promising potential for femtosecond laser in glaucoma treatment.

Hou, Dong Xia; Ngoi, Bryan K. A.; Hoh, Sek Tien; Koh, Lee Huat K.; Deng, Yuan Zi

2005-04-01

179

A comparison of rotary regenerator theory and experimental results for an air preheater for a thermal power plant  

Microsoft Academic Search

The aim of the paper is to compare results obtained based on theoretical modeling with directly measured experimental data on a full scale operating air preheater. First, the model of rotary regenerator energy transport involving longitudinal matrix heat conduction is formulated in the paper. Then a solution of the model equation system is presented with reference to authors’ former papers.

Teodor Skiepko; Ramesh K. Shah

2004-01-01

180

Results from the RHIC Beam Energy Scan  

NASA Astrophysics Data System (ADS)

In 2010 and 2011, RHIC ran a scan of several beam energies in order to map the phase boundary between hadronic and partonic matter. Au+Au collisions were studied at 200, 62.4, 39, 27, 19.6, 11.5, and 7.7 GeV. This range of collision energies is expected to produce systems that undergo the transition to hadronic matter at baryon chemical potentials that range from 25 to 450 MeV. At the lower end of the range of chemical potentials, the transition from partonic to hadronic matter will be a crossover, however at higher chemical potentials the transition is expected to be first order. Studies of the RHIC beam energy scan data are searching for signatures of the first order phase transition using signals which are sensitive to the nuclear compressibility. Studies of fluctuations are being used to identify the critical point. Additionally, studies are being pursued to identify where the new phenomena seen at the highest RHIC energies and used to establish the creation of a partonic medium will turn-off. The data from this first Beam Energy Scan have defined the key search energies for these observables. RHIC is now considering a follow-up BES-II to further examine these key energies.

Cebra, Daniel

2012-11-01

181

Deuteron induced reactions on Ho and La: Experimental excitation functions and comparison with code results  

NASA Astrophysics Data System (ADS)

Activation products of rare earth elements are gaining importance in medical and technical applications. In stacked foil irradiations, followed by high resolution gamma spectroscopy, the cross-sections for production of 161,165Er, 166gHo on 165Ho and 135,137m,137g,139Ce, 140La, 133m,133g,cumBa and 136Cs on natLa targets were measured up to 50 MeV. Reduced uncertainty is obtained by simultaneous remeasurement of the 27Al(d,x)24,22Na monitor reactions over the whole energy range. A comparison with experimental literature values and results from updated theoretical codes (ALICE-D, EMPIRE-D and the TENDL2012 online library) is discussed.

Hermanne, A.; Adam-Rebeles, R.; Tarkanyi, F.; Takacs, S.; Csikai, J.; Takacs, M. P.; Ignatyuk, A.

2013-09-01

182

Simulated and experimental results from a room temperature silicon X-ray pixel detector  

NASA Astrophysics Data System (ADS)

Simulated and experimental results are presented from a silicon X-ray pixel detector which is bump bonded to a PAC5 pixel array of read-out electronics. When coupled to a matching, fully depleted silicon detector the pre-amplifier is observed to have a linear response up to 80keV, and a pulse height resolution of around 1keV FWHM over the range 13-60keV. The Monte-Carlo N-Particle code has been used to simulate the detector response under illumination from a variety of energies. The excellent agreement observed between simulation and experiment illustrates the predictive abilities of such packages.

Mathieson, K.; Bates, R.; Iles, G. M.; Manolopoulos, S.; O'Shea, V.; Passmore, S.; Prydderch, M. L.; Rahman, M.; Seller, P.; Smith, K. M.; Thomas, S. L.; Watt, J.; Whitehill, C.

2001-03-01

183

Fabrication of nanoporous platinum thin films for hydrogen sensing: a comparison between experimental and simulation results  

NASA Astrophysics Data System (ADS)

The evolution and control of porosity in nanoporous platinum thin films have been studied both experimentally and by means of Kinetic Monte Carlo simulations. Experimentally, the sizes of the pores were controlled by a method of coarsening at different temperatures after dealloying. The KMC simulations also showed similar results which was governed by the temperature dependence of surface diffusion of the platinum atoms in the thin film. Good agreement is found between experimentally observed and simulated results.

Abburi, Aditya

2013-08-01

184

Performance of Stirling Engines (Arrangement for Experimental Results and Performance Prediction Method)  

Microsoft Academic Search

The authors have been manufactured and developed five kinds of high- and low temperature difference type Stirling engines. Their engine performance was investigated by experimental operations. And in order to consider about parameters affected to the engine performance, the experimental results were discussed and compared with the calculated results by analysis simulation methods. This paper shows an arrangement method for

Shoichi IWAMOTO; Koichi HIRATA; Fujio TODA

185

Numerical model for the performance prediction of a PEM fuel cell. Model results and experimental validation  

Microsoft Academic Search

This work presents a Computational Fluid Dynamics (CFD) model developed for a 50cm2 fuel cell with parallel and serpentine flow field bipolar plates, and its validation against experimental measurements. The numerical CFD model was developed using the commercial ANSYS FLUENT software, and the results obtained were compared with the experimental results in order to perform a model validation. A single

Alfredo Iranzo; Miguel Muñoz; Felipe Rosa; Javier Pino

2010-01-01

186

Energy metabolism of experimental wounds at various oxygen environments.  

PubMed Central

Energy metabolism of healing tissue was studied in experimental wounds of rats chronically breathing 11% O2, air or 55% O2. Increasing oxygen supply elevated both PO2 and PCO2 in the wound tissue. At the early phases of healing hypoxic wounds contained less DNA than normoxic or hyperoxic tissues. In hypoxia the accumulation of wound collagen was clearly retarded. Furthermore, tissue taken from wounds healing in hypoxic environments and tested ex vivo in air showed decreased capacity for glucose utilization, lactate production and oxygen consumption. Concentrations of AMP, ADP and ATP in repair tissue increased as healing progressed. The more oxygen available the higher the amounts of ADP and ATP. The AMP content was not affected by changes in local oxygen tension. These results support the earlier concept that the supply of oxygen in healing tissue may be rate-limitimg. Reduction of available oxygen either by systemic hypoxia or by increased diffusion distance impedes healing.

Kivisaari, J; Vihersaari, T; Renvall, S; Niinikoski, J

1975-01-01

187

Comparison between Theoretical Calculation and Experimental Results of Excitation Functions for Production of Relevant Biomedical Radionuclides  

SciTech Connect

The radionuclide production for biomedical applications has been brought up in the years, as a special nuclear application, at INFN LASA Laboratory, particularly in co-operation with the JRC-Ispra of EC. Mainly scientific aspects concerning radiation detection and the relevant instruments, the measurements of excitation functions of the involved nuclear reactions, the requested radiochemistry studies and further applications have been investigated. On the side of the nuclear data evaluations, based on nuclear model calculations and critically selected experimental data, the appropriate competence has been developed at ENEA Division for Advanced Physics Technologies. A series of high specific activity accelerator-produced radionuclides in no-carrier-added (NCA) form, for uses in metabolic radiotherapy and for PET radiodiagnostics, are investigated. In this work, last revised measurements and model calculations are reviewed for excitation functions of natZn(d,X)64Cu, 66Ga reactions, referring to irradiation experiments at K=38 variable energy Cyclotron of JRC-Ispra. Concerning the reaction data for producing 186gRe and 211At/211gPo (including significant emission spectra) and 210At, most recent and critically selected experimental results are considered and discussed in comparison with model calculations paying special care to pre-equilibrium effects estimate and to the appropriate overall parameterization. Model calculations are presented for 226Ra(p,2n)225Ac reaction, according to the working program of the ongoing IAEA CRP on the matter.

Menapace, E. [ENEA, Division for Advanced Physics Technologies, via Don Fiammelli 2, I-40128 Bologna (Italy); Birattari, C.; Bonardi, M.L.; Groppi, F.; Morzenti, S.; Zona, C. [Universita degli Studi di Milano, via F.lli Cervi 201, I-20090 Segrate, Milan (Italy); INFN-Milano, LASA, Radiochemistry Laboratory, via F.lli Cervi 201, I-20090 Segrate, Milan (Italy)

2005-05-24

188

A comparison of experimental and theoretical electron energy distribution functions in a multicusp ion source  

Microsoft Academic Search

Experimental and theoretical electron energy distribution functions (EEDFs) measured in and calculated for the driver of a multicusp ion source operating in hydrogen are compared. The results show that atomic physics based theoretical models can accurately predict the EEDF in such discharges if some appropriate experimentally determined quantities are used as input parameters. The magnitude and shape of the EEDF

J. Bretagne; W. G. Graham; M. B. Hopkins

1991-01-01

189

Beam energy scan results from PHENIX  

NASA Astrophysics Data System (ADS)

Probes like J/? and ?0 production are very important for studying the properties of the strongly interacting partonic medium created in heavy ion collisions. Their production is strongly suppressed in =200 GeV Au + Au collisions, in comparison to the expectation from binary collision scaled p + p collisions. The recent low-energy scan at RHIC provided the PHENIX collaboration with an opportunity to study the evolution of the suppression at =39 and 62.4 GeV center of mass energies in order to disentangle multiple contributing mechanisms. The suppression of J/? observed is similar to those previously measured at 200 GeV. In contrast neutral pion suppression shows a distinct energy dependence at moderate pT region of the central collisions.

Sen, Abhisek; PHENIX Collaboration

2013-08-01

190

Optimal slew maneuver of a flexible spacecraft - Analytical and experimental results  

NASA Astrophysics Data System (ADS)

This paper presents the analytical and experimental results for optimal slew maneuver of a flexible spacecraft. The experimental setup simulate pitch axis motion of a flexible appendage connecting a reflector. The primary actuators are a reaction wheel and a thruster system mounted on the central body. The simulator floats on airpads above the granite table. Several control techniques, proportional-derivative control, reference trajectories, optimal control, were evaluated analytically and experimentally for slew maneuvers. Reference trajectory using sinusoidal torque profile provides a best performance. Kalman filter estimator to estimate flexible modes was found to be unsatisfactory. Thruster control was also used for slew maneuvers. The analytical and experimental results are in good agreement.

Agrawal, B. N.; Hailey, J.

1992-08-01

191

Experimental evidence of transient growth of energy before airfoil flutter  

Microsoft Academic Search

This paper presents experimental evidence of the transient growth of energy for the coupled-mode flutter of an airfoil. The phenomenon occurs even in linearly stable dynamical systems. Its application is new in the context of fluid–structure interactions where only theoretical and numerical studies of transient growth exist. The experimental set-up allows an NACA 0015 airfoil to oscillate in rotational and

P. Hémon; E. de Langre; P. Schmid

2006-01-01

192

Experimental results obtained with the positron-annihilation- radiation telescope of the Toulouse-Argonne collaboration  

SciTech Connect

We present laboratory measurements obtained with a ground-based prototype of a focusing positron-annihilation-radiation telescope developed by the Toulouse-Argonne collaboration. This balloon-borne telescope has been designed to collect 511-keV photons with an extremely low instrumental background. The telescope features a Laue diffraction lens and a detector module containing a small array of germanium detectors. It will provide a combination of high spatial and energy resolution (15 arc sec and 2 keV, respectively) with a sensitivity of {approximately}3{times}10{sup {minus}5} photons cm{sup {minus}2}s{sup {minus}1}. These features will allow us to resolve a possible narrow 511-keV line both energetically and spatially within a Galactic center ``microquasar`` or in other broad-class annihilators. The ground-based prototype consists of a crystal lens holding small cubes of diffracting germanium crystals and a 3{times}3 germanium array that detects the concentrated beam in the focal plane. Measured performances of the instrument at different line energies (511 keV and 662 keV) are presented and compared with Monte-Carlo simulations. The advantages of a 3{times}3 Ge-detector array with respect to a standard-monoblock detector have been confirmed. The results obtained in the laboratory have strengthened interest in a crystal-diffraction telescope, offering new perspectives for die future of experimental gamma-ray astronomy.

Naya, J.E.; von Ballmoos, P.; Albernhe, F.; Vedrenne, G. [Centre d`Etude Spatial des Rayonnements, Toulouse (France); Smither, R.K.; Faiz, M.; Fernandez, P.B.; Graber, T. [Argonne National Lab., IL (United States)

1995-10-01

193

Initial Experimental Results from the Alcator C-Mod Compact Neutral Particle Analyzer  

NASA Astrophysics Data System (ADS)

Recent experimental results from the new Compact Neutral Particle Analyzer (CNPA) and a completed multi-detector upgrade of the diagnostic are presented. The CNPA uses Si diodes to detect charge-exchanged (CX) induced energetic (>20keV) neutral particles for ICRF hydrogen minority tail temperature diagnosis. A diagnostic neutral beam (DNB) provides the neutrals for the CX process. The discussed data involve measurements of the on-axis Hydrogen-minority perpendicular energy spectrum during low density (n_eo ˜ 10^20/m^3) ICRF D(H) plasmas with 0.5 to 1.5MW of ICRF. During these discharges, tail temperatures reached ˜ 200keV. The energy spectrum is compared with TRANSP and Stix-distribution based calculations, and central ICRF power deposition densities are inferred. The upgrade consists of the installation of three additional detectors which provides the diagnostic with multiple sightlines. Using a new long-pulse DNB, the improved CNPA will give spatial and temporal tail temperature measurements for moderate (n_eo ˜ 2x10^20/m^3) densities C-Mod D(H) plasmas.

Tang, V.; Parker, R.; Liptac, J.; Egedal, J.; Fiore, C.; Granetz, R.; Hubbard, A.; Irby, J.; Lin, Y.; Mossessian, D.; Wukitch, S.; Zhurovich, K.; Rowan, W.

2004-11-01

194

Experimental results of a low-power roadheader driving a gallery with different types of rock at the face  

Microsoft Academic Search

In this paper, the experimental results of a 45-kW and 15-t roadheader excavating a gallery with two different types of rock at the face using two different cutting heads are shown. It is proved that the roadheader works properly with both cutting heads. In comparison with other results in the literature, the principal parameters, i.e. specific energy, cutting rate and

J. Toraño Álvarez; M. Menéndez Álvarez; R. Rodr??guez D??ez

2003-01-01

195

Activating Performance Expectations and Status Differences through Gift Exchange: Experimental Results  

ERIC Educational Resources Information Center

|Early theoretical work on social exchange focused on how exchange relations generate social structural outcomes. Specifically, gift giving was said to evoke status structures. No experimental evidence exists to verify or refute the notion that gift giving during exchange processes generates status hierarchies. We present experimental results

Bienenstock, Elisa Jayne; Bianchi, Alison J.

2004-01-01

196

Guided waves in a plate with linearly varying thickness: experimental and numerical results  

Microsoft Academic Search

The aim of this work is to give experimental and numerical results on the behaviour of guided waves that propagate downslope in a free elastic plate with slowly linearly varying thickness. We show experimentally the propagation of adiabatic modes, which are guided waves that adapt to the varying thickness of the plate. As the thickness is decreasing, a given guided

M. Ech-Cherif El-Kettani; F Luppé; A Guillet

2004-01-01

197

Plasma enhanced machining of Inconel 718: modeling of workpiece temperature with plasma heating and experimental results  

Microsoft Academic Search

A numerical and experimental analysis of plasma enhanced machining (PEM) of Inconel 718 is presented in this paper. Surface temperatures due to plasma heating are systematically characterized through numerical modeling and experimental investigation using infrared radiation thermometry. A three-dimensional finite difference model is established to determine the temperature distribution in a cylindrical workpiece subjected to intense localized heating. The results

Carl E. Leshock; Jin-Nam Kim; Yung C. Shin

2001-01-01

198

Ply drop-off effects in CFRP\\/honeycomb sandwich panels—experimental results  

Microsoft Academic Search

The results of a combined experimental and theoretical investigation of local bending effects induced by ply drop-off in CFRP\\/honeycomb sandwich panels are presented. The objective of the investigation was to validate a simple model for engineering analysis of sandwich panels with tapered face laminates presented in a previous paper. The experimental investigation was conducted by using electronic speckle pattern interferometry

O. T. Thomson; W. Rits; D. C. G. Eaton; O. Dupont; P. Queekers

1996-01-01

199

Experimental and Numerical Results on Earthquake-Induced Rotational Ground Motions  

Microsoft Academic Search

Stimulated by the lack of direct measurements of earthquake-induced ground rotations, a set of experimental and numerical results on rotational ground motion is illustrated. The results cover a relatively broad range of magnitude (4–6.5), and regard both far field and near source conditions. Experimentally, results are derived through a suitable spatial interpolation procedure of displacement records collected from two dense

Chiara Smerzini; Roberto Paolucci; Marco Stupazzini

2009-01-01

200

Bent crystal analyzer without grooves for inelastic scattering -- first experimental results  

SciTech Connect

A new design of a bent crystal analyzer for high energy resolution inelastic X-ray scattering has been recently proposed. It has been theoretically predicted that an analyzer with reflecting planes at a certain angle with respect to a crystal surface, bent with two different radii of curvature, will have the same energy resolution as a perfect crystal. The first experimental measurement obtained at the Advanced Photon Source of a bandwidth of such an analyzer is presented. The overall energy resolution of the analyzer and monochromator observed with a narrow beam is equal to 16.4 meV (FWHM) at 13.84 KeV.

Kushnir, V.I.; Macrander, A.T.

1996-11-01

201

Theoretical and experimental analysis of the energy balance of extensive green roofs  

Microsoft Academic Search

This paper analyzed the energy balance of extensive green roofs and presented a simple but practical energy balance model. Field experiment justified the validation and accuracy of this model. Experimental results demonstrated that within 24h of a typical summer day, when soil was rich in water content, solar radiation accounted for 99.1% of the total heat gain of a Sedum

Chi Feng; Qinglin Meng; Yufeng Zhang

2010-01-01

202

Experimental Eddy Current Measurements of Flawed Edges Compared with Results from Probabilistic Numerical Models (Preprint).  

National Technical Information Service (NTIS)

Eddy current detection of flaws in edges presents challenges in experimental procedures during benchmark studies in the laboratory for model validation as well as practical implementation of a real world detection system. These difficulties result in dist...

J. Knopp M. Blodgett M. Cherry R. Grandhi

2011-01-01

203

Light Scattering from Deformed Droplets and Droplets with Inclusions: Volume 1 - Experimental Results.  

National Technical Information Service (NTIS)

This is the first of two volumes dealing with experimental and theoretical results from the scattering of light by deformed liquid droplets and droplets with inclusions. Characterizing droplet deformation could lead to improved measurement of droplet size...

D. R. Secker R. Greenaway P. H. Kaye E. Hirst D. Bartley

2000-01-01

204

STAR Results from the RHIC Beam Energy Scan  

NASA Astrophysics Data System (ADS)

The collision of two gold nuclei at top RHIC energy (=200 GeV) creates a new phase of matter, the quark-gluon plasma (QGP). The QGP exists at very high temperatures, T, and low baryo-chemical potentials, ?B. Both lattice QCD and experimental data indicate this transition from hadronic matter to Quark Gluon Plasma is an analytical transition (cross-over). On the other hand, systems formed at larger values of the baryo-chemical potential may undergo a first-order transition.Thus there can be an end point of the first-order transition on the QCD phase diagram, the critical point. To study the QCD phase boundary and search for the possible QCD critical point, RHIC launched a Beam Energy Scan Program. In 2010 and 2011, we collected data at =7.7, 11.5, 19.6, 27, 39 and 62.4 GeV, which covers a wide range of baryon chemical potential from ?B 420 to 40 MeV. In this article, we will report the latest results of the Beam Energy Scan Program from the STAR collaboration.

Wang, Hui; STAR Collaboration

2013-08-01

205

Correlation of the experimental and numerical results for the holding power of dental, traumatic, and spinal screws.  

PubMed

The holding power of the bone-screw interfaces is one of the key factors in the clinical performance of screw design. The value of the holding power can be experimentally measured by pullout tests. Historically, some researchers have used the finite-element method to simulate the holding power of the different screws. Among them, however, the assumed displacement of the screw withdrawal is unreasonably small (about 0.005-1.0 mm). In addition, the chosen numerical indices are quite different, including maximum stress, strain energy, and reaction force. This study systematically uses dental, traumatic, and spinal screws to experimentally measure and numerically simulate their bone-purchasing ability within the synthetic bone. The testing results (pullout displacement and holding power) and numerical indices (maximum stress, total strain energy, and reaction forces) are chosen to calculate their correlation coefficients. The pullout displacement is divided into five regions from initial to final withdrawal. The experimental results demonstrate that the pullout displacement consistently occurs at the final region (0.6-1.6 mm) and is significantly higher than the assumed value of the literature studies. For all screw groups, the measured holding power within the initial region is not highly or even negatively correlated with the experimental and numerical results within the final region. The observation from the simulative results shows the maximum stress only reflects the loads concentrated at some local site(s) and is the least correlated to the measured holding power. Comparatively, both energy and force are more global indices to correlate with the gross failure at the bone-screw interfaces. However, the energy index is not suitable for the screw groups with rather tiny threads compared with the other specifications. In conclusion, the underestimated displacement leads to erroneous results in the screw-pullout simulation. Among three numerical indices the reaction-force is the optimal index for the screw-pullout problem. PMID:22269112

Lee, Chia-Ching; Lin, Shang-Chih; Wu, Shu-Wei; Li, Yu-Ching; Fu, Ping-Yuen

2012-01-23

206

Theoretical and experimental results of a fully ballistic nano-FET with high gain  

Microsoft Academic Search

We report on the experimental evidence of a fully ballistic nano-FET with a voltage gain higher than 1 which is based on a 1D quantum ballistic conductor. In such a FET, the transconductance and the output conductance are basically modulated by the 1D subbands and the experimental results can theoretically be explained based on the Landauer-Buttiker formalism and the Buttiker

E. Gremion; D. Niepce; U. Gennser; A. Cavanna; Y. Jin

2008-01-01

207

The first experimental results from x-ray imaging crystal spectrometer for KSTAR  

SciTech Connect

The x-ray imaging crystal spectrometer (XICS) for the Korea Superconducting Tokamak Advanced Research has been first applied for the experimental campaign in 2009. The XICS was designed to provide measurements of the profiles of the ion and electron temperatures from the heliumlike argon (Ar XVII) spectra. The basic functions of the XICS are properly working although some satellites lines are not well matched with the expected theoretical values. The initial experimental results from the XICS are briefly described.

Lee, S. G.; Bak, J. G. [National Fusion Research Institute, Daejeon 305-333 (Korea, Republic of); Nam, U. W. [Korea Astronomy and Space Science Institute, Daejeon 305-348 (Korea, Republic of); Moon, M. K. [Korea Atomic Energy Research Institute, Daejeon 305-353 (Korea, Republic of); Shi, Y. [Institute of Plasma Physics, Chinese Academy of Science, Hefei 230031 (China); Bitter, M.; Hill, K. [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States)

2010-10-15

208

Amplification of intermethylated sites experimental design and results analysis with AIMS in silico computer software  

Microsoft Academic Search

Amplification of intermethylated sites (AIMS) is a powerful tool for differential methylation screening of genomes. Its applications\\u000a have nevertheless been limited until recently for the absence of systemic approach to AIMS experimental design and of appropriate\\u000a computer software for the analysis of AIMS results. We have developed AIMS in silico computer suggestion tool capable of predicting possible experimental outcomes, which

A. S. Tanas; V. V. Shkarupo; E. B. Kuznetsova; D. V. Zaletayev; V. V. Strelnikov

2010-01-01

209

Performance analysis of wick-assisted heat pipe solar collector and comparison with experimental results  

NASA Astrophysics Data System (ADS)

The performance of heat pipe solar collector is investigated theoretically and experimentally. The system employs wick-assisted heat pipe for the heat transfer from the absorber (evaporator) to a heat exchanger (condenser). The heat pipe is made with a copper tube and the evaporator section is finned with aluminium plate. Theoretical model predicts the outlet water from heat exchanger, heat pipe temperature and also the thermal efficiency of solar collector. The results are compared with experimental data.

Azad, E.

2009-03-01

210

One-nucleon pickup reactions on 32S: Experimental results and shell-model calculations  

NASA Astrophysics Data System (ADS)

The 32S(d,3He)31P and 32S(3He,?)31S reactions have been investigated at incident energies of Ed=27 MeV and E3He=25 MeV. The experimental values of excitation energies (0<=Ex(MeV)<=8) have been compared with the predictions of a complete sd-shell space, shell-model calculation. Spectroscopic factors obtained for 22 levels of 31S through the DWBA analysis of the experimental angular distributions have also been compared with the shell-model predictions. In order to reconcile the experimental and shell-model predicted values of the spectroscopic factors, the geometrical parameters of the spin-orbit part of the transferred nucleon potential are required to be smaller than those of the central part as it was previously observed in studies of the one-proton (3He,d) stripping reaction. The experimental fragmentation of the 1d5/2 and 2s1/2 strengths is correctly reproduced by the shell-model calculations. Twenty pairs of levels were identified as mirror states in the 31S and 31P nuclei and the ambiguities concerning the J?-values of eleven 31S levels could be removed.

Vernotte, J.; Berrier-Ronsin, G.; Fortier, S.; Hourani, E.; Khendriche, A.; Maison, J. M.; Rosier, L.-H.; Rotbard, G.; Caurier, E.; Nowacki, F.

1999-08-01

211

Of horseshoes and horse races: Experimental studies of the impact of poll results on electoral behavior  

Microsoft Academic Search

The article examines the impact of poll results on voter support for candidates. An experimental design was used to manipulate candidates' level of support in reputable opinion polls. The poll results were presented in a television newscast. The effects of the poll?related news report were assessed with regard to voters' intention to vote, their assessments of the candidates' prospects, and

Stephen Ansolabehere; Shanto Iyengar

1994-01-01

212

Experimental evidence of transient growth of energy before airfoil flutter  

NASA Astrophysics Data System (ADS)

This paper presents experimental evidence of the transient growth of energy for the coupled-mode flutter of an airfoil. The phenomenon occurs even in linearly stable dynamical systems. Its application is new in the context of fluid structure interactions where only theoretical and numerical studies of transient growth exist. The experimental set-up allows an NACA 0015 airfoil to oscillate in rotational and vertical degrees of freedom when it is subjected to air-flow. Measurements consist of time series of the two motions obtained by laser displacement sensors. Structural parameters are first estimated without air-flow. The transient evolution of energy is measured, and amplification is observed for a given set of initial conditions. Our experiments agree well with numerical simulations based on unsteady airfoil theory.

Hémon, P.; de Langre, E.; Schmid, P.

2006-04-01

213

Experimental and computational analysis on guide vane losses of impulse turbine for wave energy conversion  

Microsoft Academic Search

This paper deals with the detailed flow analysis of impulse turbine with experimental and computed results for wave energy power conversion. Initially, several turbulence models have been used in two-dimensional (2-D) computational fluid dynamic (CFD) analysis to find a suitable model for this kind of slow speed unconventional turbine. Experiments have been conducted to validate the CFD results and also

A. Thakker; T. S. Dhanasekaran

2005-01-01

214

Experimental investigation of high-energy photon splitting in atomic fields.  

PubMed

Data analysis of an experiment in which photon splitting in atomic fields was observed is presented. The experiment was performed at the tagged photon beam of the ROKK-1M facility at the VEPP-4M collider. In the energy region of 120-450 MeV, statistics of 1.6x10(9) photons incident on the BGO target was collected. About 400 candidate photon-splitting events were reconstructed. Within the attained experimental accuracy, the experimental results are consistent with the calculated exact atomic-field cross section. The predictions obtained in the Born approximation differ significantly from the experimental results. PMID:12190576

Akhmadaliev, Sh Zh; Kezerashvili, G Ya; Klimenko, S G; Lee, R N; Malyshev, V M; Maslennikov, A L; Milov, A M; Milstein, A I; Muchnoi, N Yu; Naumenkov, A I; Panin, V S; Peleganchuk, S V; Pospelov, G E; Protopopov, I Ya; Romanov, L V; Shamov, A G; Shatilov, D N; Simonov, E A; Strakhovenko, V M; Tikhonov, Yu A

2002-07-19

215

Laser induced deflection technique for absolute thin film absorption measurement: optimized concepts and experimental results  

SciTech Connect

Using experimental results and numerical simulations, two measuring concepts of the laser induced deflection (LID) technique are introduced and optimized for absolute thin film absorption measurements from deep ultraviolet to IR wavelengths. For transparent optical coatings, a particular probe beam deflection direction allows the absorption measurement with virtually no influence of the substrate absorption, yielding improved accuracy compared to the common techniques of separating bulk and coating absorption. For high-reflection coatings, where substrate absorption contributions are negligible, a different probe beam deflection is chosen to achieve a better signal-to-noise ratio. Various experimental results for the two different measurement concepts are presented.

Muehlig, Christian; Kufert, Siegfried; Bublitz, Simon; Speck, Uwe

2011-03-20

216

Predictions of Necking with Analytical Criteria and Comparisons with Experimental Results  

SciTech Connect

Two analytical approaches are detailed for the determination of Forming Limit Diagrams (F.L.D.) and compared with experimental results. The first one is the 'Enhanced Modified Maximum Force Criterion EMMFC' and the second one is the 'Through-Thickness Shear Instability Criterion TTSIC'. The criteria are both written in an intrinsic analytical form and are applicable to linear and non-linear strain paths as it occurs in any FEM codes for sheet-metal forming simulation. Finally, the two methods are complementary depending on the nature of failure and the predicted curves are in reasonable agreement with the trend of experimental results for a wide range of materials.

Brunet, Michel [INSA de Lyon, LaMCoS, 20 avenue Einstein, 69621 Villeurbanne (France); Clerc, Patrice [MECANIUM, 66 boulevard Niels Bohr, 69603 Villeurbanne (France)

2007-05-17

217

Negative refraction and lensing at visible wavelength: experimental results using a waveguide array.  

PubMed

Experimental results showing "negative refraction" and some kind of "lensing" -in the microwave-infrared range- are often presented in the literature as undisputable evidence of the existence of composite left-handed materials. The purpose of this paper is to present experimental results on "negative refraction" and "lensing" at visible wavelengths involving a waveguide array formed by a tight-packed bundle of glass fibers. We will demonstrate that the observed phenomena are not necessarily evidence of the existence of left-handed materials and that they can be fully explained by classical optic concepts, e.g. light propagation in waveguides. PMID:21747491

Ferrari, José A; Frins, Erna

2011-07-01

218

Gradual ordering in mollusk shell nacre: theoretical modeling and experimental results  

NASA Astrophysics Data System (ADS)

Biominerals have attracted the attention of materials scientists, biologists, and mineralogists as well as physicists because of their remarkable mechanical properties and incompletely elucidated formation mechanisms. Nacre, or mother-of-pearl, is a layered biomineral composite that is widely studied because of its self-assembled, efficient and accurately ordered architecture results in remarkable resistance to fracture. New experimental tools enable us to obtain new information about the organization and structure of the mineral tablets in nacre. Our experimental and theoretical investigations yield strong evidence that orientational ordering of these tablets is the result of dynamical self-organization.

Coppersmith, Susan N.

2013-03-01

219

Experimental and clinical results of breast cancer detection using UWB microwave radar  

Microsoft Academic Search

This paper presented the clinical results of breast cancer detection using a radar-based UWB microwave system developed at the University of Bristol. Additionally, the system overview and some experimental laboratory results are presented as well. For the clinical result shown in this contribution, we compare images obtained using the standard X-ray mammography and the radar-based microwave system. The developed microwave

Maciej Klemm; Ian Craddock; Jack Leendertz; Alan Preece; Ralph Benjamin

2008-01-01

220

Guided waves in a plate with linearly varying thickness: experimental and numerical results.  

PubMed

The aim of this work is to give experimental and numerical results on the behaviour of guided waves that propagate downslope in a free elastic plate with slowly linearly varying thickness. We show experimentally the propagation of adiabatic modes, which are guided waves that adapt to the varying thickness of the plate. As the thickness is decreasing, a given guided wave will reach its thickness cut-off. When this happens, we show that two phenomena occur: the reflection of this wave and its propagation backward in the plate, its conversion into a different guided wave which goes on propagating downslope in the plate. The numerical study is done with the software Ansys, based on the finite element method. The results obtained confirm the experimental ones. PMID:15047388

El-Kettani, M Ech-Cherif; Luppé, F; Guillet, A

2004-04-01

221

Interesting experimental results in Japan Proton Accelerator Research Complex H- ion-source development (invited).  

PubMed

The following interesting experimental results observed in Japan Proton Accelerator Research Complex (J-PARC) H(-) ion-source developments are reviewed. It was proven that almost all of H(-) ions were produced with surface reactions in cesium (Cs)-free J-PARC H(-) ion-sources. The world's most intense class H(-) ion current of 38 mA in Cs-free ion sources for a high-energy linac was attained by an optimal shape and high temperature of the plasma electrode (PE), usage of a lanthanum hexaboride (LaB(6)) filament, and a newly devised high-power constant-current pulsed-arc power supply indispensable for it. It was also proven that the H(-) ion current could be increased to more than 40 mA by optimizing LaB(6)-filament shape. The surface elemental analysis of the PE after operation with a LaB(6)-filament showed that it was coated by boron (B) 95.5%, lanthanum (La) 2.5%, and oxygen (O) 1.9%. The H(-) ion current decreased by about 20% when a tungsten (W) filament was used instead of a LaB(6)-filament. The H(-) ion current could not be increased by seeding cesium (Cs) if the LaB(6)-filament was used. On the other hand, it was increased to more than 70 mA with much lower arc current of 150 A if Cs was seeded when a W-filament was used. PMID:20192389

Ueno, A; Oguri, H; Ikegami, K; Namekawa, Y; Ohkoshi, K

2010-02-01

222

OVERVIEW OF RECENT EXPERIMENTAL RESULTS FROM THE DIII-D ADVANCED TOKAMAK PROGRAM  

SciTech Connect

OAK A271 OVERVIEW OF RECENT EXPERIMENTAL RESULTS FROM THE DIII-D ADVANCED TOKAMAK PROGRAM. The DIII-D research program is developing the scientific basis for advanced tokamak (AT) modes of operation in order to enhance the attractiveness of the tokamak as an energy producing system. Since the last International Atomic Energy Agency (IAEA) meeting, the authors have made significant progress in developing the building blocks needed for AT operation: (1) the authors have doubled the magnetohydrodynamic (MHD) stable tokamak operating space through rotational stabilization of the resistive wall mode; (2) using this rotational stabilization, they have achieved {beta}{sub N}H{sub 89} {le} 10 for 4 {tau}{sub E} limited by the neoclassical tearing mode; (3) using real-time feedback of the electron cyclotron current drive (ECCD) location, they have stabilized the (m,n) = (3,2) neoclassical tearing mode and then increased {beta}{sub T} by 60%; (4) they have produced ECCD stabilization of the (2,1) neoclassical tearing mode in initial experiments; (5) they have made the first integrated AT demonstration discharges with current profile control using ECCD; (6) ECCD and electron cyclotron heating (ECH) have been used to control the pressure profile in high performance plasmas; and (7) they have demonstrated stationary tokamak operation for 6.5 s (36 {tau}{sub E}) at the same fusion gain parameter of {beta}{sub N}H{sub 89}/q{sub 95}{sup 2} {approx} 0.4 as ITER but at much higher q{sub 95} = 4.2. They have developed general improvements applicable to conventional and advanced tokamak operating modes: (1) they have an existence proof of a mode of tokamak operation, quiescent H-mode, which has no pulsed, ELM heat load to the divertor and which can run for long periods of time (3.8 s or 25 {tau}{sub E}) with constant density and constant radiation power; (2) they have demonstrated real-time disruption detection and mitigation for vertical disruption events using high pressure gas jet injection of noble gases; (3) they have found that the heat and particle fluxes to the inner strike points of balanced, double-null divertors are much smaller than to the outer strike points.

BURRELL,KH

2002-11-01

223

Evolving artificial neural network structures: experimental results for biologically-inspired adaptive mutations  

Microsoft Academic Search

Previous work has suggested incorporating a biologically inspired mutation operator that reflects vertebrate neuron growth and death rates into an evolutionary algorithm for evolving artificial neural network structures. This paper further investigates this proposed approach by presenting experimental results for two classifier problems.

Damon A. Miller; Rodrigo Arguello; Garrison W. Greenwood

2004-01-01

224

Experimental results from FLEXnav: an expert rule-based dead-reckoning system for Mars rovers  

Microsoft Academic Search

This paper presents a proprioceptive position estimation system (PPE) with inertial measurement unit (IMU) uses fuzzy logic operations in conjunction with the expert rules for finer gradation called fuzzy logic expert navigation (FLEXnav) PPE system. The detailed experimental results obtained with our FLEXnav system integrated with our Mars rover clone Fluffy and operating in a Mars-like environment. The paper also

Lauro Ojeda; Giulio Reina; Johann Borenstein

2004-01-01

225

TRANSCRITICAL CO2 MOBILE HEAT PUMP AND A\\/C SYSTEM EXPERIMENTAL AND MODEL RESULTS  

Microsoft Academic Search

This article presents the results of the experimental runs of a prototype of R744 (CO2) refrigeration system operating in a both air conditioning and heat pump mode when heat rejection is done in supercritical region. The prototype system is sized for a compact car. Data presented are in the limited range of operation. Further optimization and extension of operating range

C. W. Bullard; J. M. Yin; P. S. Hrnjak

226

Mineral dissolution kinetics as a function of distance from equilibrium – New experimental results  

Microsoft Academic Search

We revisit a fundamental question in mineral dissolution kinetics, namely: is the function of dissolution rate versus the distance from equilibrium continuous, or does the “switch” between two different reaction mechanisms cause a discontinuity, i.e., a kinetic bifurcation? Based on new insight from experimental results, including direct observations of retreating crystal surfaces with vertical scanning interferometry (VSI), we present evidence

Rolf S. Arvidson; Andreas Luttge

2010-01-01

227

Columbus meteoroid\\/debris protection study - Experimental simulation techniques and results  

Microsoft Academic Search

The methods and measurement techniques used in experimental simulations of micrometeoroid and space debris impacts with the ESA's laboratory module Columbus are described. Experiments were carried out at the two-stage light gas gun acceleration facilities of the Ernst-Mach Institute. Results are presented on simulations of normal impacts on bumper systems, oblique impacts on dual bumper systems, impacts into cooled targets,

E. Schneider; K. Kitta; A. Stilp; M. Lambert; H. G. Reimerdes

1992-01-01

228

Fuel cell system integration into a heavy-duty hybrid vehicle: preliminary experimental results  

Microsoft Academic Search

This paper is the second paper dealing with the evaluation of different power sources and hybridization strategies in a heavy-duty vehicle. It focuses on the physical integration of a fuel cell system (FCS) into the vehicle as well as the preliminary experimental results obtained with the FCS coupled to batteries. The vehicle considered here is a mobile research platform (ECCE)

J. Mulot; F. Harel; S. Begot; D. Hissel; I. Rodel; S. Boblet; M. Amiet

2010-01-01

229

Principal Results of Experimental Work on the Underground Gasification of Brown Coal in the USSR.  

National Technical Information Service (NTIS)

A continuous method of gasifying a coal seam in a canal, in which artificial crushing of the seam and penetration of the seam with a dense network of boreholes are not required, has been worked out in the USSR as a result of experimental work on the under...

P. V. Skafa

1975-01-01

230

BIOTIC INDICES AND STREAM ECOSYSTEM PROCESSES: RESULTS FROM AN EXPERIMENTAL STUDY1  

Microsoft Academic Search

We investigated the ability of the North Carolina Biotic Index (NCBI) and the Ephemeroptera + Plecoptera + Trichoptera (EPT) index to track an experimental ma- nipulation of the invertebrate community and resultant alteration of several ecosystem-level processes in a headwater stream at the Coweeta Hydrologic Laboratory in western North Carolina. Indices were calculated from quantitative monthly or bimonthly benthic samples

J. BRUCE WALLACE; JACK W. GRUBAUGH; MATT R. WHILES

1996-01-01

231

Experimental and computational results of harmonically oscillating flexible and rigid flat plates  

Microsoft Academic Search

Oscillating flexible and rigid flat plates are studied with a combination of numerical simulations and experimental measurements. Visualization data and numerical simulations are used to classify the principal characteristics in the wake of the plates. Visualization data for each plate shows distinct differences between when and how efficiently thrust is produced. Visualization results show that thrust is produced at Strouhal

Scott Hightower; Paulo Ferreira de Sousa; Jeremy Pena; James Allen

2006-01-01

232

Digital MultiBeam Microwave Radiometer: system configuration and experimental result  

Microsoft Academic Search

A digital multi-beam microwave radiometer is presented in this paper. The system consists of antenna array, receiving channel array, analog to digital convertor and PC. It is the multiply beamforming technique that is used to process the signal which is obtained from the scene. An error correction algorithm is used to improve image quality. Experimental result demonstrates the image ability

Zhang Jing; Li Qingxia; Guo Wei; Zhang Tingting

2008-01-01

233

An outcome-based learning model to identify emerging threats : experimental and simulation results.  

SciTech Connect

The authors present experimental and simulation results of an outcome-based learning model as it applies to the identification of emerging threats. This model integrates judgment, decision making, and learning theories to provide an integrated framework for the behavioral study of emerging threats.

Martinez-Moyano, I. J.; Conrad, S. H.; Andersen, D. F.; Decision and Information Sciences; SNL; Univ. at Albany

2007-01-01

234

K Nearest Neighbor Edition to Guide Classification Tree Learning: Motivation and Experimental Results  

Microsoft Academic Search

This paper presents a new hybrid classifier that combines the Nearest Neighbor distance based algorithm with the Classification Tree paradigm. The Nearest Neighbor algorithm is used as a preprocessing al- gorithm in order to obtain a modified training database for the posterior learning of the classification tree structure; experimental section shows the results obtained by the new algorithm; comparing these

J. M. Mart ´ inez-Otzet; Basilio Sierra; Elena Lazkano; Aitzol Astigarraga

2006-01-01

235

Sodium laser guide star system at Lawrence Livermore National Laboratory: System description and experimental results.  

National Technical Information Service (NTIS)

The architecture and major system components of the sodium-layer kw guide star system at LLNL will be described, and experimental results reported. The subsystems include the laser system, the beam delivery system including a pulse stretcher and beam poin...

K. Avicola J. Brase J. Morris

1994-01-01

236

Experimental results on time-resolved reflectance diffuse optical tomography with fast-gated SPADs  

NASA Astrophysics Data System (ADS)

We present experimental results of time-resolved reflectance diffuse optical tomography performed with fast-gated single-photon avalanche diodes (SPADs) and show an increased imaged depth range for a given acquisition time compared to the non gated mode.

Puszka, Agathe; Di Sieno, Laura; Dalla Mora, Alberto; Pifferi, Antonio; Contini, Davide; Boso, Gianluca; Tosi, Alberto; Planat-Chrétien, Anne; Hervé, Lionel; Koenig, Anne; Dinten, Jean-Marc

2013-06-01

237

Experimental acidification of alpine catchments at Sogndal, Norway: Results after 8 years  

Microsoft Academic Search

Manipulations with whole catchments were initiated in Norway in 1983 (RAIN project Reversing Acidification In Norway) to obtain direct experimental evidence relating to the reversibility of soil and water acidification, rate of change, and the relative roles of sulfur and nitrogen. We present here results for soil and runoff chemistry during 8 years of acid addition at Sogndal, a pristine

Richard F. Wright; Erik Lotse; Arne Semb

1994-01-01

238

Vibration and damage detection in undamaged and cracked circular arches: Experimental and analytical results  

Microsoft Academic Search

This paper presents the experimental results of the dynamic behaviour of a circular arch in undamaged and several damaged configurations, and compares them with those obtained by means of analytical methods. The damage is introduced in the undamaged arch by operating a notch and is then modelled as a torsion spring of suitable stiffness localised in the damaged cross-section. Good

M. N. Cerri; M. Dilena; G. C. Ruta

2008-01-01

239

Multiple steady states in binary distillation—Theoretical and experimental results  

Microsoft Academic Search

Steady-state multiplicity and instability in distillation is studied theoretically and experimentally for columns with volumetric reflux. Using nonlinear wave propagation theory for distillation processes, we derive simple expressions for the prediction of multiplicity regions in parameter space with paper and pencil. This method also gives further insight into qualitative column dynamics in the region of multiple steady states. The results

A. Kienle; M. Groebel; E. D. Gilles

1995-01-01

240

Selected results from the technology assessment of solar energy program  

Microsoft Academic Search

Selected results on the environmental, institutional and social impacts of the large-scale deployment of decentralized solar technologies obtained by the Technology Assessment of Solar Energy program of the Department of Energy are presented. The first phase of the program is almost complete and consisted of characterizing different solar technologies and quantifying the indirect residuals of solar energy acquisition. A second

M. C. Krupka; J. H. Altseimer

1979-01-01

241

Structure identification based on steady-state control: Experimental results and applications  

NASA Astrophysics Data System (ADS)

We report experimental results on structure identification of nonlinear systems by a steady-state control method. The idea underlying the method is to drive the nonlinear system to steady state by applying a suitable feedback control input. It turns out experimentally that this control-based structure identification method can be used for some applications, such as estimation of initial conditions and state variables of nonlinear systems and structure identification of some special elements. Two attractors of the Chua oscillator are presented to illustrate the reliability of the suggested techniques under the hypotheses of measurable state variables and physical access to the system for implementing the proportional feedback.

Frasca, Mattia; Yu, Dongchuan; Fortuna, Luigi

2010-02-01

242

Conservation of Mechanical and Electric Energy: Simple Experimental Verification  

ERIC Educational Resources Information Center

|Two similar experiments on conservation of energy and transformation of mechanical into electrical energy are presented. Both can be used in classes, as they offer numerous possibilities for discussion with students and are simple to perform. Results are presented and are precise within 20% for the version of the experiment where measured values…

Ponikvar, D.; Planinsic, G.

2009-01-01

243

Design considerations and experimental results of a 100 W, 500 000 rpm electrical generator  

NASA Astrophysics Data System (ADS)

Mesoscale gas turbine generator systems are a promising solution for high energy and power density portable devices. This paper focuses on the design of a 100 W, 500 000 rpm generator suitable for use with a gas turbine. The design procedure selects the suitable machine type and bearing technology, and determines the electromagnetic characteristics. The losses caused by the high frequency operation are minimized by optimizing the winding and the stator core material. The final design is a permanent-magnet machine with a volume of 3 cm3 and experimental measurements from a test bench are presented.

Zwyssig, C.; Kolar, J. W.

2006-09-01

244

Experimental energy straggling of protons in SiO{sub 2}  

SciTech Connect

The energy straggling of proton beams in SiO{sub 2} has been measured in the energy range from 30 to 1500 keV using the transmission, nuclear reaction analysis and Rutherford backscattering techniques. The experimental results are compared with theoretical models. We observe that at energies around 200 keV the values obtained are larger than theoretical estimations. The straggling effect produced by the electron bunching in molecular media was calculated and it was found to be a possible cause of these differences at intermediate energies.

Santos, J.H.R. dos; Grande, P.L.; Behar, M.; Dias, J.F.; Arista, N.R.; Eckardt, J.C.; Lantschner, G.H. [Instituto de Fisica da Universidade Federal do Rio Grande do Sul, Avenida Bento Goncalves 9500, 91501-970, Porto Alegre, Rio Grande do Sul (Brazil); Centro Atomico Bariloche, Comision Nacional de Energia Atomica, RA-8400 San Carlos de Bariloche (Argentina)

2003-10-01

245

Experimental results on current-driven turbulence in plasmas - a survey  

NASA Astrophysics Data System (ADS)

The experimental consequences of plasma turbulence driven by a current parallel to a magnetic field and concurrent anomalous plasma heating are reviewed, with an attempt to deduce universalities in key parameters such as the anomalous electrical conductivities observed in diverse devices. It has been found that the nature of plasma turbulence and turbulent heating depends on several parameters including the electric field, current and magnetic fields. A classification of turbulence regimes based on these parameters has been made. Experimental observations of the anomalous electrical conductivity, plasma heating, skin effect, runaway electron braking and turbulent fluctuations are surveyed, and current theoretical understanding is briefly reviewed. Experimental results recently obtained in stellarators (SIRIUS, URAGAN at Kharkov), and in tokamaks (TORTUR at Nieuwegein, STOR-1M at Saskatoon) are presented in some detail in the light of investigating the feasibility of using turbulent heating as a means of injecting a large power into toroidal devices.

de Kluiver, H.; Perepelkin, N. F.; Hirose, A.

1991-01-01

246

New experimental results on GPS\\/INS navigation for Ocean Voyager II AUV  

Microsoft Academic Search

This paper presents preliminary experimental results on small-sized autonomous underwater vehicle navigation in shallow water environments. The vehicle was chosen to be our second-generation Ocean Voyager II which has been integrated with on-board GPS\\/INS sensors. These first-cut results reveal practical problems when using raw GPS fixes to perform high-precision real-time navigation. Among these, the most damaging factor is the observed

P. E. An; A. J. Healey; S. M. Smith; S. E. Dunn

1996-01-01

247

Phase shifts in the EXAFS of crystalline iron-experimental results and theoretical calculations  

NASA Astrophysics Data System (ADS)

For crystalline iron, it has been shown that the approximation of the spherical photoelectron wave by a plane wave causes systematic errors. Shell-dependent energy shifts E0 up to 10 eV are necessary to correct these errors of the plane-wave SSCA (small-scattering-centre approximation). An analytical expression E0(R) is given which can be used as preinformation in the analysis of an experimental EXAFS spectrum. Consequently, the great number of free parameters, especially the ``dummy'' energy zeros for different coordination shells at a distance R, can be reduced drastically. Furthermore, two approximations within the curved-wave theory, MSSCA (modified small-scattering-centre approximation) and RAME (reduced angular momentum expansion), that partially correct the systematic E0 errors are proposed.

Zschech, E.; Rennert, P.

1989-10-01

248

Propagation effects for land mobile satellite systems: Overview of experimental and modeling results  

NASA Astrophysics Data System (ADS)

Models developed and experiments performed to characterize the propagation environment associated with land mobile communication using satellites are discussed. Experiments were carried out with transmitters on stratospheric balloons, remotely piloted aircraft, helicopters, and geostationary satellites. This text is comprised of compiled experimental results for the expressed use of communications engineers, designers of planned Land Mobile Satellite Systems (LMSS), and modelers of propagation effects. The results presented here are mostly derived from systematic studies of propagation effects for LMSS geometries in the United States associated with rural and suburban regions. Where applicable, the authors also draw liberally from the results of other related investigations in Canada, Europe, and Australia. Frequencies near 1500 MHz are emphasized to coincide with frequency bands allocated for LMSS by the International Telecommunication Union, although earlier experimental work at 870 MHz is also included.

Goldhirsh, Julius; Vogel, Wolfhard J.

1992-02-01

249

Experimental investigation of a novel steam ejector refrigerator suitable for solar energy applications  

Microsoft Academic Search

The paper presents the results of an experimental investigation of a novel steam jet refrigerator suitable for solar energy applications. The primary flow of the ejector is controlled using a spindle in order to provide fine tuning and for ejector operation as well as optimum coefficient of performance. The influence of the spindle position, and the boiler temperature, as well

Xiaoli Ma; Wei Zhang; S. A. Omer; S. B. Riffat

2010-01-01

250

Experimental validation of a CFD model for tubes in a phase change thermal energy storage system  

Microsoft Academic Search

A computational fluid dynamic (CFD) model for tubes in a phase change thermal energy storage system has been developed and validated with experimental results. The heat transfer fluid (HTF) flows in tubes which are configured in a unique arrangement during the charging and discharging processes. Water was used as the phase change material (PCM) which was contained in a cylindrical

N. H. S. Tay; F. Bruno; M. Belusko

251

Comparison of 2D Hybrid Simulational and Experimental Results for Dual-Frequency Capacitively Coupled Argon Plasmas  

NASA Astrophysics Data System (ADS)

A two-dimensional hybrid simulation scheme is proposed to study the characteristics of dual-frequency (DF) capacitively coupled plasma (CCP) discharge based on the geometry of real device. Given the experimental parameters for argon plasma, the output from the fluid module such as ion density, number flux, electron temperature and the Monte-Carlo collision (MCC) results of ion energy distribution function (IEDF) as well as electron energy distribution function (EEDF) are obtained and discussed in detail. A novel complete floating double probe is designed to measure both density and temperature of electron and a quadrupole mass spectrometer is also equipped for IEDF investigations. The measurements on the density of bulk plasma, electron temperature and IEDF agree well, qualitatively, with the simulated results. A comparison with experimental results indicates that, since the structure of real device is taken into account, this model is capable of describing the global dynamic characteristics occurred in DF-CCP and presenting more reliable results than the model with an ideal chamber structure.

Bi, Zhenhua; Xu, Xiang; Liu, Yongxin; Jiang, Xiangzhan; Lu, Wenqi; Wang, Younian

2011-04-01

252

Au L? x-rays induced by photons from 241Am: Comparison of experimental results and the predictions of PENELOPE.  

PubMed

The results of experiments performed, measuring the L? x-rays emitted by Au due to excitation by photons of various energies from an (241)Am sample at forward-scattered angles in the range 0° to 65°, are compared to the predictions of the Monte Carlo code, PENELOPE. The experimental data are in good agreement with the predictions of the program. A comparison of the angular distributions of the probability densities (as predicted by the program) related to the Au L? and L? x-rays suggests that PENELOPE does not simulate the phenomena described by Flügge et al. (1972). PMID:21890370

Gonzales, D; Requena, S; Williams, S

2011-08-25

253

Experimental calibration of the SORI-CID internal energy scale: energy uptake and loss  

Microsoft Academic Search

This paper describes a novel method to experimentally determine the net amount of internal energy deposited into biomolecules during sustained off-resonance irradiation collision-induced dissociation (SORI-CID). The method of calibration is based on a controlled manipulation of the initial internal energy of a trapped ion population prior to dissociation. A decrease in the initial internal energy will lead to an increase

Xinghua Guo; Marc C. Duursma; Ahmed Al-Khalili; Ron M. A. Heeren

2003-01-01

254

Numerical and experimental results for focusing of three-dimensional electromagnetic waves into uniaxial crystals.  

PubMed

We present experimental results for focusing of a three-dimensional electromagnetic wave through a plane interface into two different uniaxial crystals, a positive MgF2 crystal and a negative LiNbO3 crystal. These results are compared with numerical results and good agreement is found, both for intensity distributions in various receiving planes and for the locations of the sagittal and tangential focal planes. The theory is briefly outlined both for the exact solution, which includes extraparaxial geometries and double refraction, and for the paraxial solution, in which double refraction is ignored. PMID:19252667

Jain, Momodou; Lotsberg, Jon Kåre; Stamnes, Jakob J; Frette, Øyvind; Velauthapillai, Dhayalan; Jiang, Daya; Zhao, Xiaohong

2009-03-01

255

Bistatic frequency-swept microwave imaging: Principle, methodology and experimental results  

SciTech Connect

The basic principle, methodology and experimental results of frequency-swept microwave imaging of continuous shape conducting and discrete line objects in a bistatic scattering arrangement are presented. Theoretical analysis is developed under the assumptions of plane wave illumination and physical optics approximation. The measurement system and calibration procedures are implemented based on the plane wave spectrum analysis. Images of three different types of scattering objects reconstructed from the experimental data measured in the frequency range 7.5-12.5 GHz are shown in good agreement with the scattering object geometries. The results demonstrate that the developed bistatic frequency-swept microwave imaging system has potential as a cost-effective tool for the application of remote sensing, imaging radar, and nondestructive evaluation.

Dingbing Lin; Tahhsiung Chu (National Taiwan Univ., Taipei, (Taiwan, Province of China). Electrical Engineering Dept.)

1993-05-01

256

REFLECTIONS ON MY CONTRIBUTIONS TO PARTICLE PHYSICS AND RECENT EXPERIMENTAL RESULTS FROM RHIC.  

SciTech Connect

My talk today will be composed of two parts. The first part will consist of a summary of some of my experimental contributions over the years. It will not be exhaustive but will highlight the findings that had relevance to the progress of our understanding of particle physics as it has evolved over the years. This section will be divided into three periods: Early, Intermediate and Late, with an in depth discussion of a few of the more significant results. The second part will consist of a discussion of the recently completed Relativistic Heavy Ion Collider (RHIC) machine at Brookhaven National Laboratory (BNL). This will encompass the parameters of the accelerator and some of the interesting and exciting early experimental results emanating from this machine.

SAMIOS,N.P.

2002-01-18

257

Parallel Path Magnet Motor: Development of the Theoretical Model and Analysis of Experimental Results  

NASA Astrophysics Data System (ADS)

Analytical and numerical modelling is performed for the linear actuator of a parallel path magnet motor. In the model based on finite-element analysis, the 3D problem is reduced to a 2D problem, which is sufficiently precise in a design aspect and allows modelling the principle of a parallel path motor. The paper also describes a relevant numerical model and gives comparison with experimental results. The numerical model includes all geometrical and physical characteristics of the motor components. The magnetic flux density and magnetic force are simulated using FEMM 4.2 software. An experimental model has also been developed and verified for the core of switchable magnetic flux linear actuator and motor. The results of experiments are compared with those of theoretical/analytical and numerical modelling.

Dirba, I.; Kleperis, J.

2011-01-01

258

Experimental determination of fragment excitation energies in multifragmentation events  

NASA Astrophysics Data System (ADS)

For 50 MeV/nucleon 129Xe+natSn multifragmentation events, we deduced, by means of correlation techniques, the multiplicities of the hydrogen and helium isotopes which were emitted by the hot primary excited fragments produced at the stage of the disassembly of an equilibrated hot source. We also derived the relative kinetic energy distributions between the primary clusters and the light charged particles that they evaporate. From the comparison between the secondary multiplicities observed experimentally and the multiplicities predicted by the GEMINI model, we concluded that the source breaks into primary fragments which are characterized by the same N/Z ratio as the combined system. Knowing the secondary light charged particle multiplicities and kinetic energies, we reconstructed the average charges of the hot fragments and we estimated their mean excitation energies. The fragment excitation energies are equal to 3.0 MeV/nucleon for the full range of intermediate mass fragment atomic number. This global constancy indicates that, on the average, thermodynamical equilibrium was achieved at the disassembly stage of the source.

Marie, N.; Chbihi, A.; Natowitz, J. B.; Le Fèvre, A.; Salou, S.; Wieleczko, J. P.; Gingras, L.; Assenard, M.; Auger, G.; Bacri, Ch. O.; Bocage, F.; Borderie, B.; Bougault, R.; Brou, R.; Buchet, P.; Charvet, J. L.; Cibor, J.; Colin, J.; Cussol, D.; Dayras, R.; Demeyer, A.; Doré, D.; Durand, D.; Eudes, P.; Frankland, J. D.; Galichet, E.; Genouin-Duhamel, E.; Gerlic, E.; Germain, M.; Gourio, D.; Guinet, D.; Hagel, K.; Lautesse, P.; Laville, J. L.; Lecolley, J. F.; Lefort, T.; Legrain, R.; Le Neindre, N.; Lopez, O.; Louvel, M.; Majka, Z.; Maskay, A. M.; Nalpas, L.; Nguyen, A. D.; Parlog, M.; Péter, J.; Plagnol, E.; Rahmani, A.; Reposeur, T.; Rivet, M. F.; Rosato, E.; Saint-Laurent, F.; Steckmeyer, J. C.; Stern, M.; Tabacaru, G.; Tamain, B.; Tirel, O.; Vient, E.; Volant, C.; Wada, R.

1998-07-01

259

Experimental determination of fragment excitation energies in multifragmentation events  

SciTech Connect

For 50 MeV/nucleon {sup 129}Xe+{sup nat}Sn multifragmentation events, we deduced, by means of correlation techniques, the multiplicities of the hydrogen and helium isotopes which were emitted by the hot primary excited fragments produced at the stage of the disassembly of an equilibrated hot source. We also derived the relative kinetic energy distributions between the primary clusters and the light charged particles that they evaporate. From the comparison between the secondary multiplicities observed experimentally and the multiplicities predicted by the GEMINI model, we concluded that the source breaks into primary fragments which are characterized by the same N/Z ratio as the combined system. Knowing the secondary light charged particle multiplicities and kinetic energies, we reconstructed the average charges of the hot fragments and we estimated their mean excitation energies. The fragment excitation energies are equal to 3.0 MeV/nucleon for the full range of intermediate mass fragment atomic number. This global constancy indicates that, on the average, thermodynamical equilibrium was achieved at the disassembly stage of the source. {copyright} {ital 1998} {ital The American Physical Society}

Marie, N.; Natowitz, J.B.; Cibor, J.; Hagel, K.; Wada, R. [Cyclotron Institute, Texas AM University, College Station, Texas 77843-3366 (United States); Chbihi, A.; Le Fevre, A.; Salou, S.; Wieleczko, J.P.; Gingras, L.; Auger, G.; Laville, J.L.; Saint-Laurent, F.; Tirel, O. [GANIL, CEA, IN2P3-CNRS, B.P. 5027, F-14021 Caen Cedex (France); Assenard, M.; Eudes, P.; Germain, M.; Rahmani, A.; Reposeur, T. [SUBATECH, Universite de NANTES, Ecole des Mines de NANTES, IN2P3-CNRS, F-44072 Nantes Cedex 03 (France); Bacri, C.O.; Borderie, B.; Frankland, J.D.; Plagnol, E.; Rivet, M.F. [Institut de Physique Nucleaire, IN2P3-CNRS, F-91406 Orsay Cedex (France); Bocage, F.; Bougault, R.; Brou, R.; Colin, J.; Cussol, D.; Durand, D.; Genouin-Duhamel, E.; Lecolley, J.F.; Lefort, T.; Le Neindre, N.; Lopez, O.; Louvel, M.; Nguyen, A.D.; Peter, J.; Steckmeyer, J.C.; Tamain, B.; Vient, E. [LPC, IN2P3-CNRS, ISMRA et Universite, F-14050 Caen Cedex (France); Buchet, P.; Charvet, J.L.; Dayras, R.; Dore, D.; Legrain, R.; Nalpas, L.; Volant, C. [DAPNIA/SPhN, CEA/Saclay, F-91191 Gif sur Yvette Cedex (France); Demeyer, A.; Galichet, E.; Gerlic, E.; Guinet, D.; Lautesse, P.; Maskay, A.M.; Stern, M. [IPN Lyon, IN2P3-CNRS et Universite, F-69622 Villeurbanne Cedex (France); Parlog, M.; Tabacaru, G. [National Institute for Physics and Nuclear Engineering, RO-76900 Bucharest-Magurele (Romania); Rosato, E. [Dipartimento di Scienze Fisiche, Univ. di Napoli, 180126 Napoli (Italy); Gourio, D. [Gesellschaft fuer Schwerionenforschung, D-64291 Darmstadt (Germany); Majka, Z. [Institute of Physics, Jagellonian University ul. Roeymonta 4, 30-059 Krakow (Poland)

1998-07-01

260

Experimental and husbandry procedures as potential modifiers of the results of phenotyping tests.  

PubMed

To maximize the sensitivity of detecting affects of genetic variants in mice, variables have been minimized through the use of inbred mouse lines, by eliminating infectious organisms and controlling environmental variables. However, the impact of standard animal husbandry and experimental procedures on the validity of experimental data is under appreciated. In this study we monitored the impact of these procedures by using parameters that reflect stress and physiological responses to it. Short-term measures included telemetered heart rate and systolic arterial pressure, core body temperature and blood glucose, while longer-term parameters were assessed such as body weight. Male and female C57BL6/NTac mice were subjected to a range of stressors with different perceived severities ranging from repeated blood glucose and core temperature measurement procedures, intra-peritoneal injection and overnight fasting to cage transport and cage changing.Our studies reveal that common husbandry and experimental procedures significantly influence mouse physiology and behaviour. Systolic arterial pressure, heart rate, locomotor activity, core temperature and blood glucose were elevated in response to a range of experimental procedures. Differences between sexes were evident, female mice displayed more sustained cardiovascular responses and locomotor activity than male mice. These results have important implications for the design and implementation of multiple component experiments where the lasting effects of stress from previous tests may modify the outcomes of subsequent ones. PMID:22713295

Gerdin, Anna-Karin; Igosheva, Natalia; Roberson, Laura-Anne; Ismail, Ozama; Karp, Natasha; Sanderson, Mark; Cambridge, Emma; Shannon, Carl; Sunter, David; Ramirez-Solis, Ramiro; Bussell, James; White, Jacqueline K

2012-07-16

261

Experimental and husbandry procedures as potential modifiers of the results of phenotyping tests  

PubMed Central

To maximize the sensitivity of detecting affects of genetic variants in mice, variables have been minimized through the use of inbred mouse lines, by eliminating infectious organisms and controlling environmental variables. However, the impact of standard animal husbandry and experimental procedures on the validity of experimental data is under appreciated. In this study we monitored the impact of these procedures by using parameters that reflect stress and physiological responses to it. Short-term measures included telemetered heart rate and systolic arterial pressure, core body temperature and blood glucose, while longer-term parameters were assessed such as body weight. Male and female C57BL6/NTac mice were subjected to a range of stressors with different perceived severities ranging from repeated blood glucose and core temperature measurement procedures, intra-peritoneal injection and overnight fasting to cage transport and cage changing. Our studies reveal that common husbandry and experimental procedures significantly influence mouse physiology and behaviour. Systolic arterial pressure, heart rate, locomotor activity, core temperature and blood glucose were elevated in response to a range of experimental procedures. Differences between sexes were evident, female mice displayed more sustained cardiovascular responses and locomotor activity than male mice. These results have important implications for the design and implementation of multiple component experiments where the lasting effects of stress from previous tests may modify the outcomes of subsequent ones.

Gerdin, Anna-Karin; Igosheva, Natalia; Roberson, Laura-Anne; Ismail, Ozama; Karp, Natasha; Sanderson, Mark; Cambridge, Emma; Shannon, Carl; Sunter, David; Ramirez-Solis, Ramiro; Bussell, James; White, Jacqueline K.

2012-01-01

262

Closed Loop Two-Phase Thermosyphon of Small Dimensions: a Review of the Experimental Results  

Microsoft Academic Search

A bibliographical review on the heat and mass transfer in gravity assisted Closed Loop Two Phase Thermosyphons (CLTPT) with\\u000a channels having a hydraulic diameter of the order of some millimetres and input power below 1 kW is proposed. The available\\u000a experimental works in the literature are critically analysed in order to highlight the main results and the correlation between\\u000a mass flow

Alessandro Franco; Sauro Filippeschi

263

ISS-b experimental results on global distributions of ionospheric parameters and thunderstorm activity  

Microsoft Academic Search

Experimental results from the Ionosphere Sounding Satellite-b (ISS-b) are presented, with emphasis on the global distribution of such ionospheric parameters as (1) critical frequency (foF2); (2) the probability of occurrence of spread echoes; (3) nighttime electron temperature and ionic constituents of the ambient plasma; and (4) thunderstorms detected by means of radio technique. Detailed maps are presented for all four

N. Matuura; M. Kotaki; S. Miyazaki; E. Sagawa; I. Iwamoto

1981-01-01

264

Columbus meteoroid/debris protection study - Experimental simulation techniques and results  

NASA Astrophysics Data System (ADS)

The methods and measurement techniques used in experimental simulations of micrometeoroid and space debris impacts with the ESA's laboratory module Columbus are described. Experiments were carried out at the two-stage light gas gun acceleration facilities of the Ernst-Mach Institute. Results are presented on simulations of normal impacts on bumper systems, oblique impacts on dual bumper systems, impacts into cooled targets, impacts into pressurized targets, and planar impacts of low-density projectiles.

Schneider, E.; Kitta, K.; Stilp, A.; Lambert, M.; Reimerdes, H. G.

1992-08-01

265

FIRST EXPERIMENTAL RESULTS FROM DEGAS, THE QUANTUM LIMITED BRIGHTNESS ELECTRON SOURCE  

SciTech Connect

The construction of DEGAS (DEGenerate Advanced Source), a proof of principle for a quantum limited brightness electron source, has been completed at the Lawrence Berkeley National Laboratory. The commissioning and the characterization of this source, designed to generate coherent single electron 'bunches' with brightness approaching the quantum limit at a repetition rate of few MHz, has been started. In this paper the first experimental results are described.

Zolotorev, Max S.; Commins, Eugene D.; Oneill, James; Sannibale, Fernando; Tremsin, Anton; Wan, Weishi

2008-06-23

266

Phase Partitioning of Common Alcohols With BTEX Compounds in Water: Comparison Between Modeling and Experimental Results  

Microsoft Academic Search

This study compares the modeling and experimental results on the equilibrium phase partitioning behavior of three common alcohols (ethanol, isopropanol, and methanol) in a two-phase system consisting of water and a BTEX compound. A previously developed computer program is used to generate ternary phase diagrams for each alcohol-water-NAPL mixture combination, where the required activity coefficients are estimated using the UNIFAC

K. Y. Lee

2007-01-01

267

Novosibirsk terahertz free electron laser: Facility development and new experimental results at the user stations  

Microsoft Academic Search

The Novosibirsk FEL (NovoFEL) generates tunable monochromatic coherent radiation as a continuous stream of 100-ps pulses with a repetition rate of up to 11.2 MHz and average power of up to 500 W. After commissioning of the second laser resonator in 2010, the spectral ranges of 120–240 ?m and 40–80 ?m are available to users. A review of experimental results

B. A. Knyazev; V. S. Cherkassky; E. N. Chesnokov; Yu. Yu. Choporova; M. A. Dem'yanenko; D. G. Esaev; V. V. Gerasimov; Ya. V. Getmanov; T. N. Goryachkovskaya; E. I. Kolobanov; V. V. Kubarev; G. N. Kulipanov; L. E. Medvedev; E. V. Naumova; A. A. Nikitin; A. K. Nikitin; S. V. Miginsky; S. E. Peltek; B. Z. Persov; V. V. Pickalov; V. M. Popik; V. Ya. Prinz; T. V. Salikova; M. A. Scheglov; S. S. Serednyakov; O. A. Shevchenko; A. N. Skrinsky; N. A. Vinokurov; M. G. Vlasenko; N. S. Zaigraeva

2011-01-01

268

Rheometry of a dacitic melt: Experimental results and tests of empirical models for viscosity estimation  

SciTech Connect

This paper reports on experimental measurements of the viscosity of a dacitic melt, by means of the technique of of concentric cylinder rheometry. The measurements were done in a temperature range of 1000 to 1150[degrees]C, and at different shear rates. The results were compared with empirical models which are commonly used to estimate the viscosity of single-phase melts of silicates. This data is of great use to the study of magma transport.

Stein, D.J.; Spera, F.J. (Univ. of California, Santa Barbara, CA (United States))

1993-09-15

269

Experimental and simulated results of a SMES fed by a current source inverter  

Microsoft Academic Search

This paper presents the first experimental results obtained with a 6-pulse, 50 kW GTO current source inverter (CSI) feeding a 25 kJ superconducting coil. This SMES system is the first step into the project AMAS500 which consists of developing a 1 MJ SMES fed by a 500 kW CSI. The complete system will be in operation at the end of

I. J. Iglesias; A. Bautista; M. Visiers

1997-01-01

270

Search for muonium to antimuonium conversion: Overview and recent experimental results  

SciTech Connect

The motivation for an experimental search for muonium to antimuonium conversion is briefly discussed. Results of measurements on limits for the strength of the coupling constant involved in this interaction are summarized with emphasis on the recently completed search, LAMPF E985. Plans are presented for an upcoming next generation experiment, LAMF E1073, which aims at an improvement in the sensitivity by more than two orders of magnitude.

Reiner Schaefer, H.

1988-11-20

271

Mechanical behaviour of a syntactic foam\\/glass fibre composite sandwich: experimental results  

Microsoft Academic Search

This note presents the main results of an experimental investigation into the mechanical behaviour of a composite sandwich conceived as a lightweight material for naval engineering applications. The sandwich structure is formed by a three-dimensional glass fibre\\/polymer matrix fabric with transverse piles interconnecting the skins; the core is filled with a polymer matrix\\/glass microspheres syntactic foam; additional Glass Fibre Reinforced

Enrico Papa; Egidio Rizzi

2001-01-01

272

Electro-Optic Sampling at the TESLA Test Accelerator: Experimental Setup and First Results  

Microsoft Academic Search

Abstract A mode-locked titanium-sapphire laser with 15 fs pulse width is used to determine the temporal profile of the ultrashort electron bunches in the linear TESLA Test accelerator. The experimental setup is described and first results are presented on the synchronization of the Ti:Sa laser with the radio frequency of the superconducting accelerator and on the coincidence measurements between the

M. Brunken; H. Genz; P. Gottlicher; C. Hessler; M. Huning; H. Loos; A. Richter; H. Schlarb; P. Schmuser; S. Simrock; D. Suetterlin; M. Tonutti; D. Turke; Physikalisches Insitut Iiia; Rwth Aachen

273

Experimental and theoretical results on electron emission in collisions between partially dressed ions with He targets  

NASA Astrophysics Data System (ADS)

Experimental and theoretical results for electron emission in 440 keV u-1 Li+ with He targets are presented. Theoretical cross-sections are obtained using extensions of the continuum distorted wave and the continuum distorted wave-eikonal initial state models to the case of dressed projectiles and a four-body classical trajectory Monte-Carlo. The contributions of electron emission from the different aggregates of the collision system are investigated.

Monti, J. M.; Fiol, J.; Fregenal, D.; Fainstein, P. D.; Rivarola, R. D.; Wolff, W.; Horsdal, E.; Bernardi, G.; Suárez, S.

2013-09-01

274

3.1: Experimental results from a high-power broadband 18-beam klystron  

Microsoft Academic Search

We present the results of experimental measurements on an 18-beam S-band multiple-beam klystron. The electron gun has met its perveance design goal of 4.8 ?Perv with very good beam transmission (>97% in the absence of rf). Preliminary rf testing has shown amplification across the full 400-MHz band (2.9 to 3.3 GHz). The MBK was recently re-gunned to correct a high

David K. Abe; Dean E. Pershing; Edward L. Wright; Khanh T. Nguyen; Franklin N. Wood; Robert E. Myers; Edward L. Eisen; Baruch Levush

2010-01-01

275

SCWO of salt containing artificial wastewater using a transpiring-wall reactor: Experimental results  

Microsoft Academic Search

Experimental results using a transpiring-wall reactor (TWR) for supercritical water oxidation (SCWO) containing a hydrothermal flame as an internal heat source are presented. Our reactor set-up is aimed at overcoming the problem of reactor fouling and plugging due to precipitation of salts. Two types of transpiring-wall elements with different porosity were investigated. Experiments with artificial wastewater containing methanol and sodium

K. Príkopský; B. Wellig; Ph. Rudolf von Rohr

2007-01-01

276

Electrical conductivity of skeletal muscle tissue: Experimental results from different muscles in vivo  

Microsoft Academic Search

For a quantitative EMG analysis reliable and unique values of the electrical conductivities of skeletal muscle tissuein vivo are indispensable. Literature values do not satisfy these criteria. In the paper experimental results of conductivity measurements\\u000a (four-electrode technique) on musclesin vivo on which quantitative EMG experiments are also carried out are reported. Depending on the interelectrode distance (IED) in\\u000a the four-electrode

F. L. H. Gielen; W. Wallinga-de Jonge; K. L. Boon

1984-01-01

277

Experimental reconstruction of excitation energies of primary hot isotopes in heavy ion collisions near the Fermi energy  

NASA Astrophysics Data System (ADS)

The excitation energies of the primary hot isotopes in multifragmentation events are experimentally reconstructed in the reaction system 64Zn + 112Sn at 40 MeV/nucleon. A kinematical focusing method is employed to evaluate the multiplicities of the evaporated light particles associated with isotopically identified fragments with 3?Z?14. Angular distributions of the velocity spectra of light charged particles and neutrons associated with trigger isotopes are examined. A moving source fit is used to separate the kinematically correlated particles, evaporated from the parents of the detected isotopes, from the uncorrelated particles originating from other sources. The latter are evaluated experimentally relative to those in coincidence with the Li isotopes. A parameter, k, is used to adjust the yield of the uncorrelated particles for different trigger isotopes. For each experimentally detected isotope, the multiplicities, apparent temperatures, and k values for n, p, d, t, and ? particles are extracted. Using the extracted values, the excitation energies of the primary hot isotopes are reconstructed employing a Monte Carlo method. The extracted excitation energies are in the range of 1 to 4 MeV/nucleon but show a significant decreasing trend as a function of A for a given Z of the isotopes. The results are compared with those of antisymmetrized molecular dynamics (AMD) and statistical multifragmentation model (SMM) simulations. While some of the experimental characteristics are predicted partially by each model, neither simulation reproduces the overall characteristics of the experimental results.

Rodrigues, M. R. D.; Lin, W.; Liu, X.; Huang, M.; Zhang, S.; Chen, Z.; Wang, J.; Wada, R.; Kowalski, S.; Keutgen, T.; Hagel, K.; Barbui, M.; Bottosso, C.; Bonasera, A.; Natowitz, J. B.; Materna, T.; Qin, L.; Sahu, P. K.; Schmidt, K. J.

2013-09-01

278

Chemical kinetic modeling of high pressure propane oxidation and comparison to experimental results. Revision 1  

SciTech Connect

A pressure dependent kinetic mechanism for propane oxidation is developed and compared to experimental data from a high pressure flow reactor. Experimental conditions range from 10--15 atm, 650--800 K, and a residence time of 198 ms for propane-air mixtures at an equivalence ratio of 0.4. The experimental results clearly indicate a negative temperature coefficient (NTC) behavior. The chemistry describing this phenomena is critical in understanding automotive engine knock and cool flame oscillations. Results of the numerical model are compared to a spectrum of stable species profiles sampled from the flow reactor. Rate constants and product channels for the reaction of propyl radicals, hydroperoxy-propyl radicals and important isomers (radicals) with O{sub 2} were estimated using thermodynamic properties, with multifrequency quantum Kassel Theory for k(E) coupled with modified strong collision analysis for fall-off. Results of the chemical kinetic model show an NTC region over nearly the same temperature regime as observed in the experiments. Sensitivity analysis identified the key reaction steps that control the rate of oxidation in the NTC region. The model reasonably simulates the profiles for many of the major and minor species observed in the experiments.

Koert, D.N. [Wichita State Univ., KS (United States). Mechanical Engineering Dept.; Pitz, W.J. [Lawrence Livermore National Lab., CA (United States); Bozzelli, J.W. [New Jersey Inst. of Tech., Newark, NJ (United States). Chemistry and Chemical Engineering Dept.; Cernansky, N.P. [Drexel Univ., Philadelphia, PA (United States). Dept. of Mechanical Engineering and Mechanics

1996-02-01

279

Experimental kerma coefficients of biologically important materials at neutron energies below 75 MeV.  

PubMed

The present work summarizes our results already published on cross sections and partial kerma coefficients for hydrogen, carbon, and oxygen and then applies them for determining experimental partial and total kerma coefficients of composite biologically important materials. Double-differential cross sections for light-charged particle production (proton, deuteron, triton, and alpha particle) induced by fast neutrons on hydrogen, carbon, and oxygen have been experimentally measured at several incident energies from 25 to 75 MeV. The measurements covered the laboratory angular range 20 degrees to 160 degrees and were extended to very forward and very backward angles by using a reliable extrapolation procedure. Energy-differential, angle-differential, and total production cross sections were derived from the measured data. The experimental methods and data reduction procedures are briefly presented here. The experimental cross sections were compared to existing data in the literature for nucleon-induced reactions and against prediction of nuclear models. Partial and total elemental kerma coefficients were deduced on the basis of the measured cross sections. Procedures for extrapolating the partial kerma coefficients down to the reaction threshold energies for each of the measured ejectile species have been applied to carbon and oxygen. A simple-to-use analytical formula to describe the experimental hydrogen kerma coefficients was proposed which provides the recoil kerma coefficients in the incident neutron energy range 0.3 to 100 MeV. The present article reports for the first time experimental partial kerma coefficients for composite materials of biological interest. Resulting total kerma coefficients are compared to theoretical predictions and to other experimental data. PMID:11128307

Meulders, J P; Benck, S; Slypen, I; Corcalciuc, V

2000-11-01

280

Monte Carlo simulation of RBS spectra: Comparison to experimental and empirical results  

NASA Astrophysics Data System (ADS)

For low projectile energies, Rutherford backscattering (RBS) spectra from thin targets show a low energy background which can be explained by plural and multiple scattering of the projectiles. Knowledge about the influence of plural and multiple scattering on the shape of RBS spectra is important in many fields (e.g. RBS depth profiling, determination of projectile energy loss). Analytic calculation of RBS spectra with full inclusion of plural and multiple scattering is impossible. Therefore we used Monte Carlo computer simulations to calculate RBS spectra for 100-200 keV protons backscattered by thin gold films (1000 Å). In order to limit the number of scattering events, a nonzero minimum scattering angle (cutoff angle) was used in the simulations. The cutoff angle must be chosen so small that a further reduction does not change the shape of the total spectrum to a significant extent. Therefore, for various cutoff angles, the contribution of single, double and plural scattering to the total RBS spectrum is discussed. Furthermore, simulated spectra are compared to experimental data and to the empirical formula presented by Weber and Mommsen [2].

Steinbauer, Erich; Bauer, Peter; Biersack, Jochen

1990-01-01

281

Ultra-high-energy cosmic rays: the experimental situation  

NASA Astrophysics Data System (ADS)

The methods of detection of high-energy cosmic rays are briefly described and it is shown that results on the energy spectrum and arrival direction distribution obtained above 4×1019eV confound theoretical expectation. There is an urgent need for better statistics as only about 12 events above 1020eV have been detected and the limit to the energy which cosmic rays can reach is not known. The new, funded, instruments, the Pierre Auger Observatory and the Hi-Res fluorescence detector, are described and the plans for an ambitious satellite observatory (Airwatch/OWL) are outlined.

Watson, A. A.

2000-08-01

282

OVERVIEW OF RECENT EXPERIMENTAL RESULTS FROM THE DIII-D ADVANCED TOKAMAK PROGRAM  

SciTech Connect

OAK A271 OVERVIEW OF RECENT EXPERIMENTAL RESULTS FROM THE DIII-D ADVANCED TOKAMAK PROGRAM. The DIII-D research program is developing the scientific basis for advanced tokamak (AT) modes of operation in order to enhance the attractiveness of the tokamak as an energy producing system. Since the last International Atomic Energy Agency (IAEA) meeting, they have made significant progress in developing the building blocks needed for AT operation: (1) they have doubled the magnetohydrodynamic (MHD) stable tokamak operating space through rotational stabilization of the resistive wall mode; (2) using this rotational stabilization, they have achieved {beta}{sub N}H{sub 89} {ge} 10 for 4 {tau}{sub E} limited by the neoclassical tearing mode; (3) using real-time feedback of the electron cyclotron current drive (ECCD) location, they have stabilized the (m,n) = (3,2) neoclassical tearing mode and then increased {beta}{sub T} by 60%; (4) they have produced ECCD stabilization of the (2,1) neoclassical tearing mode in initial experiments; (5) they have made the first integrated AT demonstration discharges with current profile control using ECCD; (6) ECCD and electron cyclotron heating (ECH) have been used to control the pressure profile in high performance plasmas; and (7) they have demonstrated stationary tokamak operation for 6.5 s (36 {tau}{sub E}) at the same fusion gain parameter of {beta}{sub N}H{sub 89}/q{sub 95}{sup 2} {approx} 0.4 as ITER but at much higher q{sub 95} = 4.2. The authors have developed general improvements applicable to conventional and advanced tokamak operating modes: (1) they have an existence proof of a mode of tokamak operation, quiescent H-mode, which has no pulsed, ELM heat load to the divertor and which can run for long periods of time (3.8 s or 25 {tau}{sub E}) with constant density and constant radiated power; (2) they have demonstrated real-time disruption detection and mitigation for vertical disruption events using high pressure gas jet injection of noble gases; (3) they have found that the heat and particle fluxes to the inner strike points of balanced, double-null divertors are much smaller than to the outer strike points. They have made detailed investigations of the edge pedestal and SOL: (1) Atomic physics and plasma physics both play significant roles in setting the width of the edge density barrier in H-mode; (2) ELM heat flux conducted to the divertor decreases as density increases; (3) Intermittent, bursty transport contributes to cross field particle transport in the scrape-off layer (SOL) of H-mode and, especially, L-mode plasmas.

BURRELL,HK

2002-11-01

283

First experimental results and simulation for gas optimisation of the MART-LIME detector  

NASA Astrophysics Data System (ADS)

A large area high pressure multi-wire proportional counter (MWPC), with both spatial and spectroscopic capabilities, is being jointly developed by the Istituto di Astrofisica Spaziale (IAS), CNR, Frascati, Italy and the Daresbury Laboratory (DL), Warrington, UK as part of the MART-LIME telescope. Recent test results (October-December 1995) carried out at the DL facilities are presented. A brief study, by means of a simulation program, on the possible gas mixtures to be employed in the MART-LIME detector is also reported. The results of the simulation are compared with the experimental data obtained from the tests.

Bazzano, A.; Brunetti, M. T.; Cocchi, M.; Hall, C. J.; Lewis, R. A.; Natalucci, L.; Ortuño-Prados, F.; Ubertini, P.

1996-02-01

284

Experimental Results of NWCF Run H4 Calcine Dissolution Studies Performed in FY-98 and -99  

SciTech Connect

Dissolution experiments were performed on actual samples of NWCF Run H-4 radioactive calcine in fiscal years 1998 and 1999. Run H-4 is an aluminum/sodium blend calcine. Typical dissolution data indicates that between 90-95 wt% of H-4 calcine can be dissolved using 1gram of calcine per 10 mLs of 5-8M nitric acid at boiling temperature. Two liquid raffinate solutions composed of a WM-188/aluminum nitrate blend and a WM-185/aluminum nitrate blend were converted into calcine at the NWCF. Calcine made from each blend was collected and transferred to RAL for dissolution studies. The WM-188/aluminum nitrate blend calcine was dissolved with resultant solutions used as feed material for separation treatment experimentation. The WM-185/aluminum nitrate blend calcine dissolution testing was performed to determine compositional analyses of the dissolved solution and generate UDS for solid/liquid separation experiments. Analytical fusion techniques were then used to determine compositions of the solid calcine and UDS from dissolution. The results from each of these analyses were used to calculate elemental material balances around the dissolution process, validating the experimental data. This report contains all experimental data from dissolution experiments performed using both calcine blends.

Garn, Troy Gerry; Herbst, Ronald Scott; Batcheller, Thomas Aquinas; Sierra, Tracy Laureena

2001-08-01

285

Experimental and theoretical study of the energy loss of C and O in Zn  

SciTech Connect

We present a combined experimental-theoretical study of the energy loss of C and O ions in Zn in the energy range 50-1000 keV/amu. This contribution has a double purpose, experimental and theoretical. On the experimental side, we present stopping power measurements that fill a gap in the literature for these projectile-target combinations and cover an extended energy range, including the stopping maximum. On the theoretical side, we make a quantitative test on the applicability of various theoretical approaches to calculate the energy loss of heavy swift ions in solids. The description is performed using different models for valence and inner-shell electrons: a nonperturbative scattering calculation based on the transport cross section formalism to describe the Zn valence electron contribution, and two different models for the inner-shell contribution: the shellwise local plasma approximation (SLPA) and the convolution approximation for swift particles (CasP). The experimental results indicate that C is the limit for the applicability of the SLPA approach, which previously was successfully applied to projectiles from H to B. We find that this model clearly overestimates the stopping data for O ions. The origin of these discrepancies is related to the perturbative approximation involved in the SLPA. This shortcoming has been solved by using the nonperturbative CasP results to describe the inner-shell contribution, which yields a very good agreement with the experiments for both C and O ions.

Cantero, E. D.; Lantschner, G. H.; Arista, N. R. [Centro Atomico Bariloche and Instituto Balseiro, Comision Nacional de Energia Atomica, 8400 San Carlos de Bariloche (Argentina); Montanari, C. C.; Miraglia, J. E. [Instituto de Astronomia y Fisica del Espacio (CONICET-UBA), Buenos Aires (Argentina); Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires (Argentina); Behar, M.; Fadanelli, R. C. [Instituto de Fisica, Universidade Federal do Rio Grande do Sul, Avenida Bento Goncalves 9500, Porto Alegre-RS (Brazil)

2011-07-15

286

Comparison between maximum radial expansion of ultrasound contrast agents and experimental postexcitation signal results  

PubMed Central

Experimental postexcitation signal data of collapsing Definity microbubbles are compared with the Marmottant theoretical model for large amplitude oscillations of ultrasound contrast agents (UCAs). After taking into account the insonifying pulse characteristics and size distribution of the population of UCAs, a good comparison between simulated results and previously measured experimental data is obtained by determining a threshold maximum radial expansion (Rmax) to indicate the onset of postexcitation. This threshold Rmax is found to range from 3.4 to 8.0 times the initial bubble radius, R0, depending on insonification frequency. These values are well above the typical free bubble inertial cavitation threshold commonly chosen at 2R0. The close agreement between the experiment and models suggests that lipid-shelled UCAs behave as unshelled bubbles during most of a large amplitude cavitation cycle, as proposed in the Marmottant equation.

King, Daniel A.; O'Brien, William D.

2011-01-01

287

Design and Experimental Results for the S825 Airfoil; Period of Performance: 1998-1999  

SciTech Connect

A 17%-thick, natural-laminar-flow airfoil, the S825, for the 75% blade radial station of 20- to 40-meter, variable-speed and variable-pitch (toward feather), horizontal-axis wind turbines has been designed and analyzed theoretically and verified experimentally in the NASA Langley Low-Turbulence Pressure Tunnel. The two primary objectives of high maximum lift, relatively insensitive to roughness and low-profile drag have been achieved. The airfoil exhibits a rapid, trailing-edge stall, which does not meet the design goal of a docile stall. The constraints on the pitching moment and the airfoil thickness have been satisfied. Comparisons of the theoretical and experimental results generally show good agreement.

Somers, D. M.

2005-01-01

288

Design and Experimental Results for the S827 Airfoil; Period of Performance: 1998--1999  

SciTech Connect

A 21%-thick, natural-laminar-flow airfoil, the S827, for the 75% blade radial station of 40- to 50-meter, stall-regulated, horizontal-axis wind turbines has been designed and analyzed theoretically and verified experimentally in the NASA Langley Low-Turbulence Pressure Tunnel. The primary objective of restrained maximum lift has not been achieved, although the maximum lift is relatively insensitive to roughness, which meets the design goal. The airfoil exhibits a relatively docile stall, which meets the design goal. The primary objective of low profile drag has been achieved. The constraints on the pitching moment and the airfoil thickness have been satisfied. Comparisons of the theoretical and experimental results generally show good agreement with the exception of maximum lift, which is significantly underpredicted.

Somers, D. M.

2005-01-01

289

Corrosion by liquid lead and lead-bismuth: experimental results review and analysis  

SciTech Connect

Liquid metal technologies for liquid lead and lead-bismuth alloy are under wide investigation and development for advanced nuclear energy systems and waste transmutation systems. Material corrosion is one of the main issues studied a lot recently in the development of the liquid metal technology. This study reviews corrosion by liquid lead and lead bismuth, including the corrosion mechanisms, corrosion inhibitor and the formation of the protective oxide layer. The available experimental data are analyzed by using a corrosion model in which the oxidation and scale removal are coupled. Based on the model, long-term behaviors of steels in liquid lead and lead-bismuth are predictable. This report provides information for the selection of structural materials for typical nuclear reactor coolant systems when selecting liquid lead or lead bismuth as heat transfer media.

Zhang, Jinsuo [Los Alamos National Laboratory

2008-01-01

290

Experimental results from a DC photocathode electron gun for an IR FEL  

SciTech Connect

A 350 keV DC photocathode gun capable of delivering the high-brightness CW electron beam necessary for Jefferson Lab`s infrared free-electron laser is described. The gun is to be used with a superconducting radiofrequency linac operating at 1.497 GHz and is mode-locked to the 40th subharmonic of the fundamental using a Nd:YLF drive laser. The gun provides 20--25 ps bunches at up to 135 pC/bunch. Experimental measurements of transverse and longitudinal beam properties are presented. Transverse emittance is measured using a slit-wire scanner emittance meter, and energy spread is measured using the slit and a spectrometer magnet. Longitudinal emittance is measured using a combination of sampling aperture, kicker cavity, slit and spectrometer. Measurements for bunch charges of 135 pC are described and compared with simulations.

Kehne, D.; Engwall, D.; Legg, R.; Shinn, M.

1997-10-01

291

New results in nucleon-nucleon scattering at intermediate energies  

SciTech Connect

Many np elastic scattering spin observables have recently been measured between kinetic energies of about 500 and 1100 MeV at Saclay and LAMPF. These data are summarized and some new results are presented. Evidence for structure in pp observables near 2100 MeV is reviewed, and new data in this energy region are shown from SATURNE.

Spinka, H.

1995-01-01

292

Costs and results of federal incentives for commercial nuclear energy  

Microsoft Academic Search

This paper (1) estimates the total costs of federal expenditures in support of incentives for the development of commercial nuclear energy through 1988, and (2) analyzes the results and benefits to the nation of this federal investment. The federal incentives analyzed include research and development, regulation of commercial nuclear energy, tax incentives, waste management and disposal, enrichment plants, liability insurance,

R. H. Bezdek; R. M. Wendling

2009-01-01

293

Laboratory simulations of lidar returns from clouds - Experimental and numerical results  

NASA Astrophysics Data System (ADS)

The experimental results of laboratory simulations of lidar returns from clouds are presented. Measurements were carried out on laboratory-scaled cloud models by using a picosecond laser and a streak-camera system. The turbid structures simulating clouds were suspensions of polystyrene spheres in water. The geometrical situation was similar to that of an actual lidar sounding a cloud 1000 m distant and with a thickness of 300 m. Measurements were repeated for different concentrations and different sizes of spheres. The results show how the effect of multiple scattering depends on the scattering coefficient and on the phase function of the diffusers. The depolarization introduced by multiple scattering was also investigated. The results were also compared with numerical results obtained by Monte Carlo simulations. Substantially good agreement between numerical and experimental results was found. The measurements showed the adequacy of modern electro-optical systems to study the features of multiple-scattering effects on lidar echoes from atmosphere or ocean by means of experiments on well-controlled laboratory-scaled models. This adequacy provides the possibility of studying the influence of different effects in the laboratory in well-controlled situations.

Zaccanti, Giovanni; Bruscaglioni, Piero; Gurioli, Massimo; Sansoni, Paola

1993-03-01

294

Recovery of yttrium from cathode ray tubes and lamps' fluorescent powders: experimental results and economic simulation.  

PubMed

In this paper, yttrium recovery from fluorescent powder of lamps and cathode ray tubes (CRTs) is described. The process for treating these materials includes the following: (a) acid leaching, (b) purification of the leach liquors using sodium hydroxide and sodium sulfide, (c) precipitation of yttrium using oxalic acid, and (d) calcinations of oxalates for production of yttrium oxides. Experimental results have shown that process conditions necessary to purify the solutions and recover yttrium strongly depend on composition of the leach liquor, in other words, whether the powder comes from treatment of CRTs or lamp. In the optimal experimental conditions, the recoveries of yttrium oxide are about 95%, 55%, and 65% for CRT, lamps, and CRT/lamp mixture (called MIX) powders, respectively. The lower yields obtained during treatments of MIX and lamp powders are probably due to the co-precipitation of yttrium together with other metals contained in the lamps powder only. Yttrium loss can be reduced to minimum changing the experimental conditions with respect to the case of the CRT process. In any case, the purity of final products from CRT, lamps, and MIX is greater than 95%. Moreover, the possibility to treat simultaneously both CRT and lamp powders is very important and interesting from an industrial point of view since it could be possible to run a single plant treating fluorescent powder coming from two different electronic wastes. PMID:23831004

Innocenzi, V; De Michelis, I; Ferella, F; Vegliò, F

2013-07-03

295

Experimental results of 40-kA Nb3Al conductor  

NASA Astrophysics Data System (ADS)

A 40-kA Nb3Al conductor was developed for the toroidal field (TF) coils of the experimental fusion reactors. Presently, Nb3Sn is mainly used for high-field superconductor (more than 12 T) and is commercially available in a various type. On the other hand, the critical current (Ic) degradation of the Nb3Al was only 5% under an intrinsic axial strain of 0.4%, according to the experimental results. In case of Nb3Sn, the degradation was 30%. Therefore, it is shown that Nb3Al has excellent mechanical performance and it very useful for the toroidal field coil which is operated under large electromagnetic force. However, Nb3Al is not practical to use at present due to the difficulty of its fabrication. This conductor could be operated up to the current of 46 kA at an external field of 11.2 T, which was the required field of the TF coils in the International Thermonuclear Experimental Reactor (ITER). According to this development, Nb3Al will become a useful superconductor for large-scale, high-field application, such as the fusion machine.

Takahashi, Yoshikazu; Sugimoto, Makoto; Isono, Takaaki; Oshikiri, Masayuki; Hosono, Fumikazu; Wadayama, Yoshihide; Sasaki, Tomoyuki; Hanawa, Hiromi; Seki, Shuichi; Wakabayashi, Hiroshi

1993-03-01

296

Comparison of experimental data with results of some drying models for regularly shaped products  

NASA Astrophysics Data System (ADS)

This paper presents an experimental and theoretical investigation of drying of moist slab, cylinder and spherical products to study dimensionless moisture content distributions and their comparisons. Experimental study includes the measurement of the moisture content distributions of slab and cylindrical carrot, slab and cylindrical pumpkin and spherical blueberry during drying at various temperatures (e.g., 30, 40, 50 and 60°C) at specific constant velocity ( U = 1 m/s) and the relative humidity ? = 30%. In theoretical analysis, two moisture transfer models are used to determine drying process parameters (e.g., drying coefficient and lag factor) and moisture transfer parameters (e.g., moisture diffusivity and moisture transfer coefficient), and to calculate the dimensionless moisture content distributions. The calculated results are then compared with the experimental moisture data. A considerably high agreement is obtained between the calculations and experimental measurements for the cases considered. The effective diffusivity values were evaluated between 0.741 × 10-5 and 5.981 × 10-5 m2/h for slab products, 0.818 × 10-5 and 6.287 × 10-5 m2/h for cylindrical products and 1.213 × 10-7 and 7.589 × 10-7 m2/h spherical products using the Model-I and 0.316 × 10-5-5.072 × 10-5 m2/h for slab products, 0.580 × 10-5-9.587 × 10-5 m2/h for cylindrical products and 1.408 × 10-7-13.913 × 10-7 m2/h spherical products using the Model-II.

Kaya, Ahmet; Ayd?n, Orhan; Dincer, Ibrahim

2010-05-01

297

Experimental and Analytical Studies on Pyroelectric Waste Heat Energy Conversion  

NASA Astrophysics Data System (ADS)

This study is concerned with direct conversion of thermal energy into electrical energy by subjecting pyroelectric materials to the Olsen cycle. The Olsen cycle consists of two isoelectric field and two isothermal process on the electric displacement versus electric field diagram. The energy and power generation capabilities of copolymer poly(vinylidene fluoridetrifluorethylene) [P(VDF-TrFE)] films and lead lanthanum zirconate titanate (PLZT) ceramics were evaluated by executing the Olsen cycle via so-called "stamping experiments" and "dipping experiments". The stamping experiments consisted of alternatively pressing a pyroelectric material in thermal contact with hot and cold aluminum blocks under specified electric fields. It was performed to assess the pyroelectric energy conversion performance using heat conduction. The largest energy density generated in the stamping experiments was 155 J/L/cycle with 60/40 P(VDF-TrFE) thin film at 0.066 Hz between 25 and 110°C and electric fields cycled between 20 and 35 MV/m. This energy density exceeded the 130 J/L/cycle achieved by our previous prototypical device using oscillatory laminar convective heat transfer. However, the performance was limited by poor thermal contact between the aluminum blocks and pyroelectric material and also by excessive leakage current inherent to P(VDF-TrFE) at high temperatures and/or large electric fields. On the other hand, dipping experiments consisted of successively immersing a pyroelectric material into isothermal hot and cold thermal reservoirs at different temperatures while simultaneously cycling the electric fields. It was performed on relaxor ferroelectric x/65/35 PLZT ceramics with x between 5 and 10 mol.%. The operating temperature, applied electric field, sample thickness, cycle frequency, and electrode material were systematically varied to explore their respective effects on the energy and power densities produced. A maximum energy density of 1014 J/L/cycle was obtained with a 190?m thick 7/65/35 PLZT sample at 0.0256 Hz at temperatures between 30 and 200°C and electric field from 0.2 to 7.0 MV/m. To the best of our knowledge, this energy density is the largest achieved among pyroelectric single crystals, ceramics, and polymers using the Olsen cycle. Meanwhile, a maximum power density of 55.3 ± 8.0 W/L obtained with a 190?m thick 9.5/65/35 PLZT sample at 0.125 Hz. Additionally, the temperature-dependent dielectric behavior of PLZT ceramics were characterized. The polarization transition temperature of lanthanum-doped x /65/35 PLZT ceramics decreased from 240 to 10°C for increasing lanthanum dopant concentration x from 5 to 10 mol.%. This establishes that the different compositions should be operated at different temperatures for maximum pyroelectric energy conversion. Finally, a physical thermo-electrical model for estimating the energy harvested by ferroelectric relaxors was further validated against experimental data for a wide range of electric fields and temperatures.

Lee, Felix

298

Nonlinear piezoelectricity in electroelastic energy harvesters: Modeling and experimental identification  

NASA Astrophysics Data System (ADS)

We propose and experimentally validate a first-principles based model for the nonlinear piezoelectric response of an electroelastic energy harvester. The analysis herein highlights the importance of modeling inherent piezoelectric nonlinearities that are not limited to higher order elastic effects but also include nonlinear coupling to a power harvesting circuit. Furthermore, a nonlinear damping mechanism is shown to accurately restrict the amplitude and bandwidth of the frequency response. The linear piezoelectric modeling framework widely accepted for theoretical investigations is demonstrated to be a weak presumption for near-resonant excitation amplitudes as low as 0.5 g in a prefabricated bimorph whose oscillation amplitudes remain geometrically linear for the full range of experimental tests performed (never exceeding 0.25% of the cantilever overhang length). Nonlinear coefficients are identified via a nonlinear least-squares optimization algorithm that utilizes an approximate analytic solution obtained by the method of harmonic balance. For lead zirconate titanate (PZT-5H), we obtained a fourth order elastic tensor component of c1111p=-3.6673×1017 N/m2 and a fourth order electroelastic tensor value of e3111=1.7212×108 m/V.

Stanton, Samuel C.; Erturk, Alper; Mann, Brian P.; Inman, Daniel J.

2010-10-01

299

Results of an experimental determination of limiting heat fluxes in two-phase thermosiphons  

NASA Astrophysics Data System (ADS)

Experiments were carried out on closed two-phase thermosiphons made of Kh18N10T steel to investigate the limiting heat fluxes, with emphasis on the effects of the length of the heating zone and thermosiphon diameter. Experimental results support the conclusion that changing the degree of filling of the thermosiphon with coolant over a wide range (30-100%) has no effect on the limiting heat flux. A similarity equation is obtained which makes it possible to determine the limiting heat fluxes of two-phase thermosiphons over a wide range of process variables and geometric parameters for various coolants.

Tolubinskii, V. I.; Pioro, I. L.

1983-04-01

300

Optimal sparse solution for fluorescent diffuse optical tomography: theory and phantom experimental results  

NASA Astrophysics Data System (ADS)

We present a method to accurately localize small fluorescent objects within the tissue using fluorescent diffuse optical tomography (FDOT). The proposed method exploits the localized or sparse nature of the fluorophores in the tissue as a priori information to considerably improve the accuracy of the reconstruction of fluorophore distribution. This is accomplished by minimizing a cost function that includes the L1 norm of the fluorophore distribution vector. Experimental results for a milk-based phantom using a fiber-based cw FDOT system demonstrate the capability of this method in accurately localizing small fluorescent objects deep in the phantom.

Mohajerani, Pouyan; Eftekhar, Ali A.; Huang, Jiandong; Adibi, Ali

2007-04-01

301

Comparison of the results of modeling convective heat transfer in turbulent flows with experimental data  

Microsoft Academic Search

The results of simulation of natural turbulent convection in a square air cavity measuring 0.75 × 0.75 m and having isothermal\\u000a vertical and highly heat-conducting horizontal walls are compared with the experimental data obtained for this cavity at a\\u000a Rayleigh number equal to 1.58?109. In carrying out numerical investigations, a two-dimensional, low-turbulence, two-parameter k–? model known as the low-Reynolds-number\\u000a k–?

A. I. Fomichev

2010-01-01

302

Modeling and experimental results of CdxZn1-xTe detector response  

NASA Astrophysics Data System (ADS)

We have developed a model of the statistical variations in the electrical charge transport in CdxZn1-xTe(CZT) detectors. The model includes a simulation of the charge carrier generation for each photon interaction, using a calculated absorption coefficient of the photoelectric absorption. Next, we simulate the induced signal as carriers drift towards the collecting electrode under trapping conditions with negligible detrapping. Finally, a pulse height histogram is composed simulating the spectral response of the detector and incorporating the electronic noise component. A comparison between experimental and calculated CZT spectra was performed. These results and the potential for using the model in detector design will be discussed and presented.

Watson, Michael; Chattopadhyay, Kaushik; Hillman, Damian; Hillman, Damon; Burger, Arnold; James, Ralph B.

2000-11-01

303

First X-ray fluorescence CT experimental results at the SSRF X-ray imaging beamline  

NASA Astrophysics Data System (ADS)

X-ray fluorescence CT is a non-destructive technique for detecting elemental composition and distribution inside a specimen. In this paper, the first experimental results of X-ray fluorescence CT obtained at the SSRF X-ray imaging beamline (BL13W1) are described. The test samples were investigated and the 2D elemental image was reconstructed using a filtered back-projection algorithm. In the sample the element Cd was observed. Up to now, the X-ray fluorescence CT could be carried out at the SSRF X-ray imaging beamline.

Deng, Biao; Yang, Qun; Xie, Hong-Lan; Du, Guo-Hao; Xiao, Ti-Qiao

2011-04-01

304

A perspective on thermal annealing of reactor pressure vessel materials from the viewpoint of experimental results  

SciTech Connect

It is believed that in the next decade or so, several nuclear reactor pressure vessels (RPVs) may exceed the reference temperature limits set by the pressurized thermal shock screening criteria. One of the options to mitigate the effects of irradiation on RPVs is to thermally anneal them to restore the toughness properties that have been degraded by neutron irradiation. This paper summarizes recent experimental results from work performed at the Oak Ridge National Laboratory to study the annealing response, or ``recovery`` of several irradiated RPV steels. The fracture toughness is one of the important properties used in the evaluation of the integrity of RPVs. Optimally, the fracture toughness is measured directly by fracture toughness specimens, such as compact tension or precracked Charpy specimens, but is often inferred from the results of Charpy V-notch impact specimens. The experimental results are compared to the predictions of models for embrittlement recovery which have been developed by Eason et al. Some of the issues in annealing that still need to be resolved are discussed.

Iskander, S.K.; Sokolov, M.A.; Nanstad, R.K.

1996-04-01

305

Swinging Atwood Machine: Experimental and numerical results, and a theoretical study  

NASA Astrophysics Data System (ADS)

A Swinging Atwood Machine (SAM) is built and some experimental results concerning its dynamic behaviour are presented. Experiments clearly show that pulleys play a role in the motion of the pendulum, since they can rotate and have non-negligible radii and masses. Equations of motion must therefore take into account the moment of inertia of the pulleys, as well as the winding of the rope around them. Their influence is compared to previous studies. A preliminary discussion of the role of dissipation is included. The theoretical behaviour of the system with pulleys is illustrated numerically, and the relevance of different parameters is highlighted. Finally, the integrability of the dynamic system is studied, the main result being that the machine with pulleys is non-integrable. The status of the results on integrability of the pulley-less machine is also recalled.

Pujol, O.; Pérez, J. P.; Ramis, J. P.; Simó, C.; Simon, S.; Weil, J. A.

2010-06-01

306

Oxidation of hazardous waste in supercritical water: A comparison of modeling and experimental results for methanol destruction  

SciTech Connect

Recent experiments at Sandia National Laboratories conducted in conjunction with MODEC Corporation have demonstrated successful clean- up of contaminated water in a supercritical water reactor. These experiments targeted wastes of interest to Department of Energy production facilities. In this paper we present modeling and experimental results for a surrogate waste containing 98% water, 2% methanol, and parts per million of chlorinated hydrocarbons and laser dyes. Our initial modeling results consider only methanol and water. Experimental data are available for inlet and outlet conditions and axial temperature profiles along the outside reactor wall. The purpose of our model is to study the chemical and physical processes inside the reactor. We are particularly interested in the parameters that control the location of the reaction zone. The laboratory-scale reactor operates at 25 MPa., between 300 K and 900 K; it is modeled as a plug-flow reactor with a specified temperature profile. We use Chemkin Real-Gas to calculate mixture density, with the Peng-Robinson equation of state. The elementary reaction set for methanol oxidation and reactions of other C{sub 1} and C{sub 2} hydrocarbons is based on previous models for gas-phase kinetics. Results from our calculations show that the methanol is 99.9% destroyed at 1/3 the total reactor length. Although we were not able to measure composition of the fluid inside the experimental reactor, this prediction occurs near the location of the highest reactor temperature. This indicates that the chemical reaction is triggered by thermal effects, not kinetic rates. Results from ideal-gas calculations show nearly identical chemical profiles inside the reactor in dimensionless distance. However, reactor residence times are overpredicted by nearly 150% using an ideal-gas assumption. Our results indicate that this oxidation process can be successfully modeled using gas-phase chemical mechanisms. 23 refs., 8 figs.

Butler, P.B. (Iowa Univ., Iowa City, IA (United States)); Bergan, N.E.; Bramlette, T.T. (Sandia National Labs., Albuquerque, NM (United States)); Pitz, W.J.; Westbrook, C.K. (Lawrence Livermore National Lab., CA (United States))

1991-03-17

307

Infrared emission spectroscopy of CO2 at high temperature. Part II: Experimental results and comparisons with spectroscopic databases  

NASA Astrophysics Data System (ADS)

Measurements of CO2 emission spectra at high temperature in the 2.7?m and 4.3?m regions are presented and compared to predictions from the spectroscopic databases, CDSD-4000 (Tashkun SA, Perevalov VI. CDSD-4000: high-resolution, high-temperature carbon dioxide spectroscopic databank. Journal of Quantitative Spectroscopy and Radiative Transfer 2011;112:1403-10) and HITELOR (Scutaru D, Rosenmann L, Taine J. Approximate intensities of CO2 hot bands at 2.7, 4.3 and 12?m for high temperature and medium resolution applications. Journal of Quantitative Spectroscopy and Radiative Transfer 1994;52:765-81). The measurements near 2.7?m show that CDSD-4000 provides better agreement with experimental data, especially in the band wing corresponding to very hot band emission. In the 4.3?m region, experimental intensities are generally lower than theoretical predictions but the measurements are more affected by the use of sapphire confinement tubes. The two spectroscopic databases provide closer results than in the 2.7?m region although CDSD-4000 yields here also better agreement with experimental data in band wing. Analysis of the two spectroscopic databases is carried out in terms of vibrational and rotational energy cutoff and total band emissivities.

Depraz, S.; Perrin, M. Y.; Rivière, Ph.; Soufiani, A.

2012-01-01

308

A comparison of experimental and theoretical electron energy distribution functions in the driver of a multicusp ion source  

Microsoft Academic Search

Experimental and theoretical electron energy distribution functions (EEDF) measured and calculated for the driver of a multicusp ion source operating in hydrogen are compared. The results indicate that atomic physics based theoretical models can accurately predict the EEDF in such discharges if some appropriate experimentally determined quantities are used as input parameters. The magnitude and shape of the EEDF is

J. Bretagne; W. G. Graham; M. B. Hopkins

1990-01-01

309

Thermal conductivity of silicic tuffs: predictive formalism and comparison with preliminary experimental results  

SciTech Connect

Performance of both near- and far-field thermomechanical calculations to assess the feasibility of waste disposal in silicic tuffs requires a formalism for predicting thermal conductivity of a broad range of tuffs. This report summarizes the available thermal conductivity data for silicate phases that occur in tuffs and describes several grain-density and conductivity trends which may be expected to result from post-emplacement alteration. A bounding curve is drawn that predicts the minimum theoretical matrix (zero-porosity) conductivity for most tuffs as a function of grain density. Comparison of experimental results with this curve shows that experimental conductivities are consistently lower at any given grain density. Use of the lowered bounding curve and an effective gas conductivity of 0.12 W/m{sup 0}C allows conservative prediction of conductivity for a broad range of tuff types. For the samples measured here, use of the predictive curve allows estimation of conductivity to within 15% or better, with one exception. Application and possible improvement of the formalism are also discussed.

Lappin, A. R.

1980-07-01

310

Gas-dynamic trap: an overview of the concept and experimental results  

NASA Astrophysics Data System (ADS)

A gas dynamic trap (GDT) is a version of a magnetic mirror whose characteristic features are a long mirror-to-mirror distance, which exceeds the effective mean free path of ion scattering into a loss cone, a large mirror ratio (R ˜ 100) and axial symmetry. Under these conditions, the plasma confined in a GDT is isotropic and Maxwellian. The rate at which it is lost out of the ends is governed by a set of simple gas-dynamic equations, hence the name of the device. Plasma magnetohydrodynamic stability is achieved through a plasma outflow through the end mirrors into regions, where the magnetic-field lines' curvature is favorable for this stability. A high flux volumetric neutron source based on a GDT is proposed, which benefits from the high ? achievable in magnetic mirrors. Axial symmetry also makes the GDT neutron source more maintainable and reliable, and technically simpler. This review discusses the results of a conceptual design of the GDT-based neutron source for fusion materials development and fission-fusion hybrids. The main physics issues related to plasma confinement and heating in a GDT are addressed by the experiments performed with the GDT device in Novosibirsk. The review concludes by updating the experimental results obtained, a discussion about the limiting factors in the current experiments and a brief description of the design of a future experimental device for more comprehensive modeling of the GDT-based neutron source.

Ivanov, A. A.; Prikhodko, V. V.

2013-06-01

311

Rheometry of a dacitic melt - Experimental results and tests of empirical models for viscosity estimation  

NASA Astrophysics Data System (ADS)

Empirical models have long been available for estimating the Newtonian viscosity of single-phase silicate melts from composition in terms of oxide components (Bottinga and Weill, 1972; Shaw, 1972). These models are used regularly to estimate or parametrize viscosity in field studies and fluid dynamical calculations of magmatic transport. However, few independent viscosity measurements on multicomponent melts of natural composition have been made to test the accuracy of the empirical estimation models. A series of experimental measurements of viscosity has been performed on a dacitic melt, using the technique of concentric cylinder rheometry. In the ranges of temperature and shear rate examined (1000 to 1150 C and 0.013 to 7.43/s, respectively), the melt viscosity is found to be independent of shear rate. When the viscometric results from the present study and those on a rhyolitic composition (Hochella and Brown, 1984) are compared with the results from empirical models, the model of Shaw (1972) is found to represent both sets of experimental data better than that of Bottinga and Weill (1972). This is presumably due to differences in the ranges of temperature and composition represented in the data used to construct the respective models.

Stein, Daniel J.; Spera, Frank J.

1993-09-01

312

Experimental Impeller Fragmentation of Iliocaval Thrombosis Under Tulip Filter Protection: Preliminary Results  

SciTech Connect

Purpose: To assess the efficacy of catheter fragmentation of massive caval thrombosis and of filter protection against procedure-related pulmonary embolism. Methods: In 10 sheep, a self-expanding tulip-shaped filter made from Wallstent mesh (diameter 25 mm) was introduced from the right jugular approach into the proximal inferior vena cava. Experimentally induced massive iliocaval thrombosis was fragmented by an impeller catheter (expanded diameter 14 mm), which was advanced coaxially through the sheath of the expanded filter. Post-procedural cavography and pulmonary angiography were performed to document the extent of caval recanalization and pulmonary embolism. Results: In all cases, impeller fragmentation cleared the inferior vena cava and the iliac veins of thrombi completely. Fragments washed downstream were trapped in the filter. In two of the first cases, parts of the clots caused pulmonary embolism before the filter was in place. Further events were avoided by a modification of the experimental setup. Except for some small peripheral perfusion defects in two cases, pulmonary angiograms did not show any incidence of pulmonary embolism. Conclusion: Our preliminary results suggest that impeller fragmentation of iliocaval thrombi under tulip filter protection is effective and does not cause significant pulmonary embolism.

Schmitz-Rode, Thomas; Vorwerk, Dierk; Schuermann, Karl; Guenther, Rolf W. [Department of Diagnostic Radiology, University of Technology, Klinikum Aachen, Pauwelsstrasse 30, D-52057 Aachen (Germany)

1996-04-15

313

Experimental study on centrifugal pumps energy labelling in Iran  

NASA Astrophysics Data System (ADS)

The main goal of the present study was developing the energy label instruction for small centrifugal pumps. First the types of energy labels which are popular in the world especially three types of energy labels were introduced and discussed, two of which belongs to European United and the other one is assigned to Iran. Modified Iran labelling procedure with reasons was criticized and presented as a new approach in the present study. In the next step, e a standard test rig was established for testing of the small centrifugal pumps. A standard centrifugal pump named 32-160 and 32-200 was selected as the case studies. The selected pumps were test in the test rig and then labelled using selected methods. Finally the results considered and discoursed.

Derakhshan, S.; Abdolahnejad, E.; Buzari, M.

2012-11-01

314

Oxidation of hazardous waste in supercritical water: Part 1, A comparison of modeling and experimental results for methanol destruction  

SciTech Connect

Recent experiments at Sandia National Laboratories conducted in conjunction with MODEC Corporation have demonstrated successful clean-up of contaminated water in a supercritical water reactor. These experiments targeted wastes of interest to Department of Energy (DOE) production facilities. In this paper we present modeling and experimental results for a surrogate waste containing 98% water, 2% methanol, and parts per million of chlorinated hydrocarbons and laser dyes. Our initial modeling results consider only methanol and water. Experimental data are available for inlet and outlet conditions (composition, flow rate, and temperature), and axial temperature profiles along the outside reactor wall. The purpose of our model is to study the chemical and physical processes inside the reactor. We are particularly interested in the parameters that control the location of the reaction zone. The laboratory-scale reactor operates at 25 MPa., between 300 K and 900 K; it is modeled as a plug-flow reactor with a specified temperature profile. We use Chemkin Real-Gas to calculate mixture density, with the Peng-Robinson equation of state. The elementary reaction set for methanol oxidation and reactions of other C{sub 1} and C{sub 2} hydrocarbons is based on previous models for gas-phase kinetics. Results from our calculations show that the methanol is 99.99% destroyed at 1/3 the total reactor length. Although we were not able to measure composition of the fluid inside the experimental reactor, this prediction occurs near the location of the high reactor temperature. This indicates that the chemical reaction is triggered by thermal effects, not kinetic rates. Results from ideal-gas calculations show nearly identical chemical profiles inside the reactor in dimensionless distance. However, reactor residence times are overpredicted by nearly 150% using an ideal-gas assumption.

Butler, P.B. [Iowa Univ., Iowa City, IA (United States); Bergan, N.E.; Bramlette, T.T. [Sandia National Labs., Livermore, CA (United States); Westbrook, C.K.; Pitz, W.J. [Lawrence Livermore National Lab., CA (United States)

1991-12-31

315

Oxidation of hazardous waste in supercritical water: Part 1, A comparison of modeling and experimental results for methanol destruction  

SciTech Connect

Recent experiments at Sandia National Laboratories conducted in conjunction with MODEC Corporation have demonstrated successful clean-up of contaminated water in a supercritical water reactor. These experiments targeted wastes of interest to Department of Energy (DOE) production facilities. In this paper we present modeling and experimental results for a surrogate waste containing 98% water, 2% methanol, and parts per million of chlorinated hydrocarbons and laser dyes. Our initial modeling results consider only methanol and water. Experimental data are available for inlet and outlet conditions (composition, flow rate, and temperature), and axial temperature profiles along the outside reactor wall. The purpose of our model is to study the chemical and physical processes inside the reactor. We are particularly interested in the parameters that control the location of the reaction zone. The laboratory-scale reactor operates at 25 MPa., between 300 K and 900 K; it is modeled as a plug-flow reactor with a specified temperature profile. We use Chemkin Real-Gas to calculate mixture density, with the Peng-Robinson equation of state. The elementary reaction set for methanol oxidation and reactions of other C{sub 1} and C{sub 2} hydrocarbons is based on previous models for gas-phase kinetics. Results from our calculations show that the methanol is 99.99% destroyed at 1/3 the total reactor length. Although we were not able to measure composition of the fluid inside the experimental reactor, this prediction occurs near the location of the high reactor temperature. This indicates that the chemical reaction is triggered by thermal effects, not kinetic rates. Results from ideal-gas calculations show nearly identical chemical profiles inside the reactor in dimensionless distance. However, reactor residence times are overpredicted by nearly 150% using an ideal-gas assumption.

Butler, P.B. (Iowa Univ., Iowa City, IA (United States)); Bergan, N.E.; Bramlette, T.T. (Sandia National Labs., Livermore, CA (United States)); Westbrook, C.K.; Pitz, W.J. (Lawrence Livermore National Lab., CA (United States))

1991-01-01

316

Molecular hyperpolarizabilities of push-pull chromophores: A comparison between theoretical and experimental results  

NASA Astrophysics Data System (ADS)

Electric dipole moments and static first order hyperpolarizabilities of two push-pull molecules with an extended ? electron systems have been evaluated at different computational levels and compared with the results of electro-optical absorption measurements, based on the two state model. Calculations show that: (i) the dipole moments of such elongated systems depend significantly on conformation, a thorough conformational search is necessary for a meaningful comparison between theoretical and experimental results; (ii) DFT methods, in particular CAM-B3LYP and M05-2X, yield dipole moments which compare well with those obtained by post Hartree-Fock methods (MP2) and by EOA measurements; (iii) theoretical first order hyperpolarizabilities are largely underestimated, both by MP2 and DFT methods, possibly because of the failure of two state model used in electro-optical measurements.

Capobianco, A.; Centore, R.; Noce, C.; Peluso, A.

2013-01-01

317

Experimental measurement of gas diffusivity in bitumen: Results for carbon dioxide  

SciTech Connect

A new technique is developed to measure the diffusivity of gas in bitumen as a function of composition. Results are presented for a carbon dioxide-bitumen system, which is of considerable industrial relevance. The technique employs transient pressure data obtained from a nonintrusive pressure decay experiment at constant temperature and volume. The underlying theory is presented along with a computational algorithm to calculate diffusivity. Using experimental pressure decay data in the range 25--90 C at 4 MPa, the diffusivity of carbon dioxide in bitumen is calculated. The results are compared with the limited data available in the literature. The approach is straightforward and can be easily applied to other nonvolatile liquid systems.

Upreti, S.R.; Mehrotra, A.K.

2000-04-01

318

The Biological Carbon Pump of the Ocean: Comparison of Model, Satellite and Experimental Results  

NASA Astrophysics Data System (ADS)

Organic carbon export from the surface ocean euphotic zone to deeper waters (the biological carbon pump) is the biological link between the level of atmospheric pCO2 and the concentration of dissolved inorganic carbon and oxygen in the deep sea. Effective prediction of the feed back of the ocean’s carbon cycle to anthropogenic CO2 additions requires understanding the mechanisms controlling these fluxes. Available surface-ocean pCO2 climatology indicates an oceanic source to the atmosphere of ~ 0.6 Pg C yr-1 from the equatorial region and an oceanic sink of ~ -2.3 Pg C yr-1 at latitudes > 20o. Most of the ocean CO2 sink is in the wintertime in the vicinity of the subtropical/subpolar boundaries. At the equator the biological carbon flux opposes the source of CO2 to the atmosphere from upwelling of dissolved inorganic carbon-rich waters. At the subtropical/subpolar boundaries surface-water cooling and biological processes work together in winter to create a massive oceanic CO2 sink. Here I compare model and satellite-derived estimates of the biological carbon pump with those determined experimentally. Global estimates of the biological pump from different models and satellite determinations are close; the mean and standard deviation of 8 recent estimates is 12 ± 2 Pg C yr-1. Estimates of the biological carbon pump in the major physical provinces of the open ocean from model, satellite and experimental results are less consistent but within the variability (± 50 %) of experimental determinations in the equatorial (15o S - 15o N) and subarctic (>45o N) regions. However, both model and satellite estimates are lower than values measured from biological flux tracers at subtropical (15o - 30o) time-series locations indicating that either the models are unable to reproduce environmental observations in the subtropics or that the ocean is still too undersampled to know the true biological carbon flux in this region. The role of the coastal ocean is poorly resolved in global models and difficult to determine experimentally, but satellite data suggest that biological carbon export in this region could be as large as 5 Pg C yr-1. The biological carbon pump has the greatest influence on net air-sea CO2 exchange at the equator and subtropical/subpolar boundaries. While different tracers have been used to determine biological fluxes at the equator so that model and satellite-determined fluxes can be ground-truthed in this region, there have been few experimental determinations of the biological pump at the sink regions of subtropical/subpolar boundaries. Comparing model and satellite-determined biological carbon fluxes at these locations with experimental results will probably require measurements on remote platforms because it will be necessary to resolve seasonality with time-series sampling. I present an example of how this might be done with oxygen sensors on profiling floats using data from the Northwest Pacific subtropical/subarctic boundary.

Emerson, S. R.

2010-12-01

319

Chemical kinetic modeling of high pressure propane oxidation and comparison to experimental results  

SciTech Connect

A pressure dependent kinetic mechanism for propane oxidation is developed and compared to experimental data from a high pressure flow reactor. The experiment conditions range from 10--15 atm, 650--800 K, and were performed at a residence time of 200 {micro}s for propane-air mixtures at an equivalence ratio of 0.4. The experimental results include data on negative temperature coefficient (NTC) behavior, where the chemistry describing this phenomena is considered critical in understanding automotive engine knock and cool flame oscillations. Results of the numerical model are compared to a spectrum of stable species profiles sampled from the flow reactor. Rate constants and product channels for the reaction of propyl radicals, hydroperoxy-propyl radicals and important isomers with O{sub 2} were estimated using thermodynamic properties, with multifrequency quantum Kassel Theory for k(E) coupled with modified strong collision analysis for fall-off. Results of the chemical kinetic model show an NTC region over nearly the same temperature regime as observed in the experiments. The model simulates properly the production of many of the major and minor species observed in the experiments. Numerical simulations show many of the key reactions involving propylperoxy radicals are in partial equilibrium at 10--15 atm. This indicates that their relative concentrations are controlled by a combination of thermochemistry and rate of minor reaction channels (bleed reactions) rather than primary reaction rates. This suggests that thermodynamic parameters of the oxygenated species, which govern equilibrium concentrations, are important. The modeling results show propyl radical and hydroperoxy-propyl radicals reaction with O{sub 2} proceeds, primarily, through thermalized adducts, not chemically activated channels.

Koert, D.N. [Wichita State Univ., KS (United States). Mechanical Engineering Dept.; Pitz, W.J. [Lawrence Livermore National Lab., CA (United States); Bozzelli, J.W. [New Jersey Inst. of Tech., Newark, NJ (United States). Chemistry and Chemical Engineering Dept.; Cernansky, N.P. [Drexel Univ., Philadelphia, PA (United States). Dept. of Mechanical Engineering and Mechanics

1995-11-08

320

Experimental and calculational results from the Spent Fuel Test-Climax  

SciTech Connect

The Spent Fuel Test-Climax (SFT-C) is being conducted under the technical direction of the Lawrence Livermore National Laboratory for the US Department of Energy. The SFT-C is located 420 m below surface in the Climax placed in test storage in April and May 1980. At the same time, 6 electrical elevated-temperature phase of the test. Data related to heat transfer, thermomechanical response, radiation dose, and radiation damage have been collected and are presented here, as appropriate, with calculational results. In general, measured and calculated results compare well.

Patrick, W.C.; Ramspott, L.D.; Ballou, L.B.

1982-10-14

321

Experimental Results for Four-Phase Digital Matched Filtering of Spread-Spectrum Waveforms  

Microsoft Academic Search

In this paper, the implementation and experimental testing of a noncoherent four-phase digital matched filter (DMF) is presented. The DMF represents the experimental realization of A. Baier's theory of complex valued envelope matched filtering [1].

NORM COUTURIER; JAMES WIGHT; LEROY PEARCE

1986-01-01

322

Noninvasive surface measurement of corrosion impedance of reinforcing bar in concrete - part 1: experimental results  

SciTech Connect

The corrosion state of a reinforcing steel bar in concrete can be characterized by the electrical impedance of the interface between the steel bar and the concrete. The experimental part of this study, has shown that changes in the interfacial impedance that are diagnostic of the rate and extent of the corrosion can be measured indirectly with an array of current and voltage electrodes on the concrete surface. The measured impedance, however depends on the electrical resistivity of the concrete, and the depth and diameter of the steel reinforcing bar as well as the interfacial properties. To relate the measured impedance directly to the interfacial properties, a closed-form solution to the governing Poisson's equation was developed and programmed for the potentials from arbitrary, current sources in the vicinity of the reinforcing bar. The solution uses an impedance boundary, condition for the complex impedance at the steel-concrete interface. The response of an arbitrary corrosion state can be simulated in this model by embedding the appropriate complex, frequency-dependent impedance at the interface and computing the voltage/current response that would be measured for an arbitrary placement of electrodes on the concrete surface. To simulate the experimental findings, this paper presents the modeling results by various interfacial impedances but constant concrete resistivity and constant geometry of the steel reinforcing bar This simulation confirms that important parameters of the interfacial impedance controlling corrosion kinetics such as polarization resistance and double layer capacitance are clearly, observed in the measured surface data. [References: 10

Zhang, Jieying; Monteiro, Paulo J.M.; Morrison, H. Frank

2000-11-01

323

Induced current electrical impedance tomography system: experimental results and numerical simulations.  

PubMed

In electrical impedance tomography (EIT), measurements of developed surface potentials due to applied currents are used for the reconstruction of the conductivity distribution. Practical implementation of EIT systems is known to be problematic due to the high sensitivity to noise of such systems, leading to a poor imaging quality. In the present study, the performance of an induced current EIT (ICEIT) system, where eddy current is applied using magnetic induction, was studied by comparing the voltage measurements to simulated data, and examining the imaging quality with respect to simulated reconstructions for several phantom configurations. A 3-coil, 32-electrode ICEIT system was built, and an iterative modified Newton-Raphson algorithm was developed for the solution of the inverse problem. The RMS norm between the simulated and the experimental voltages was found to be 0.08 +/- 0.05 mV (<3%). Two regularization methods were implemented and compared: the Marquardt regularization and the Laplacian regularization (a bounded second-derivative regularization). While the Laplacian regularization method was found to be preferred for simulated data, it resulted in distinctive spatial artifacts for measured data. The experimental reconstructed images were found to be indicative of the angular positioning of the conductivity perturbations, though the radial sensitivity was low, especially when using the Marquardt regularization method. PMID:15005319

Zlochiver, Sharon; Radai, M Michal; Abboud, Shimon; Rosenfeld, Moshe; Dong, Xiu-Zhen; Liu, Rui-Gang; You, Fu-Sheng; Xiang, Hai-Yan; Shi, Xue-Tao

2004-02-01

324

Preliminary experimental investigation of in vivo magnetic manipulation: results and potential application in hyperthermia.  

PubMed

The first in vivo experiments in support of a new technique for delivering stereotaxic hyperthermia have been conducted at the Experimental Surgery Facility of the University of Virginia's Medical Center. We call this technique the "Video Tumor Fighter." In each of twelve trials a single, small permanent magnet or train of small permanent magnets was implanted on the brain surface of adult canine models. In three of the trials, this "seed" (typically 6-mm diameter X 6-mm long) was moved by magnetic manipulation to different locations within the brain. In two other trials, the seed moved along the interface between the brain and the inner vault of the skull. The noncontact magnetic manipulation was accomplished by coupling the permanently magnetized seed to the large dc magnetic field gradient created by a water-cooled coil surrounding the animal's head. The seed's motions were monitored with x-ray fluoroscopy; its rate of movement was found to be approximately 0.8 mm s-1. The forces required to produce these motions were on the order of 0.07 N. We document here the instrumentation used in these trials, describe the experimental procedures employed, and discuss the technical aspects of the results. PMID:2654597

Grady, M S; Howard, M A; Molloy, J A; Ritter, R C; Quate, E G; Gillies, G T

325

Experimental and numerical results on the fluid flow driven by a traveling magnetic field  

NASA Astrophysics Data System (ADS)

A traveling magnetic field (TMF) driven flow and its transition from a laminar to a time-dependent flow is studied by means of ultrasonic Doppler velocimetry and numerical simulations. The experimental setup comprises a cylindrical cavity containing the electrically conducting model fluid GaInSn and a system of six equidistant coils, which are fed by an out-of-phase current to create an up- or downward directed TMF. Hence, a Lorentz force is induced in the melt which leads to meridional flow patterns. For numerical simulations commercial codes (Opera/Fidap) and a spectral code are used. The characteristic parameters of the magnetohydrodynamic model system are chosen close to the conditions used for vertical gradient freeze (VGF) crystal growth. The axisymmetric basic flow and its dependence on the dimensionless shielding parameter S are examined. It is shown that, for S>10, the flow velocity decreases significantly, whereas almost no influence is found for a smaller shielding parameter. The critical Reynolds number for the onset of instability is found in the range of 300 450. Good agreement between experimental results and the numerical simulations is achieved.

Lantzsch, R.; Galindo, V.; Grants, I.; Zhang, C.; Pätzold, O.; Gerbeth, G.; Stelter, M.

2007-07-01

326

Drying in porous media with gravity-stabilized fronts: Experimental results  

NASA Astrophysics Data System (ADS)

In a recent paper [Yiotis , Phys. Rev. EPLEEE81539-375510.1103/PhysRevE.85.046308 85, 046308 (2012)] we developed a model for the drying of porous media in the presence of gravity. It incorporated effects of corner film flow, internal and external mass transfer, and the effect of gravity. Analytical results were derived when gravity opposes drying and hence leads to a stable percolation drying front. In this paper, we test the theory using laboratory experiments. A series of isothermal drying experiments in glass bead packings saturated with volatile hydrocarbons is conducted. The transparent glass cells containing the packing allow for the visual monitoring of the phase distribution patterns below the surface, including the formation of liquid films, as the gaseous phase invades the pore space, and for the control of the thickness of the diffusive mass boundary layer over the packing. The experimental results agree very well with theory, provided that the latter is generalized to account for the effects of corner roundness in the film region (which was neglected in the theoretical part). We demonstrate the existence of an early constant rate period (CRP), which lasts as long as the films saturate the surface of the packing, and of a subsequent falling rate period (FRP), which begins practically after the detachment of the film tips from the external surface. During the CRP, the process is controlled by diffusion within the stagnant gaseous phase in the upper part of the cells, yielding a Stefan tube problem solution. During the FRP, the process is controlled by diffusion within the packing, with a drying rate inversely proportional to the observed position of the film tips in the cell. Theoretical and experimental results compare favorably for a specific value of the roundness of the films, which is found to be constant and equal to 0.2 for various conditions, and verify the theoretical dependence on the capillary Caf, Bond Bo, and Sherwood Sh numbers.

Yiotis, A. G.; Salin, D.; Tajer, E. S.; Yortsos, Y. C.

2012-08-01

327

Experimental Limit on the Cosmic Diffuse Ultrahigh Energy Neutrino Flux  

Microsoft Academic Search

We report results from 120 hours of livetime with the Goldstone Lunar\\u000aUltra-high energy neutrino Experiment (GLUE). The experiment searches for <10\\u000ans microwave pulses from the lunar regolith, appearing in coincidence at two\\u000alarge radio telescopes separated by 22 km and linked by optical fiber. Such\\u000apulses would arise from subsurface electromagnetic cascades induced by\\u000ainteractions of >= 100

P. W. Gorham; C. L. Hebert; K. M. Liewer; C. J. Naudet; D. Saltzberg; D. Williams

2004-01-01

328

Implementation and experimental results of 4D tumor tracking using robotic couch  

PubMed Central

Purpose: This study presents the implementation and experimental results of a novel technique for 4D tumor tracking using a commercially available and commonly used treatment couch and evaluates the tumor tracking accuracy in clinical settings. Methods: Commercially available couch is capable of positioning the patient accurately; however, currently there is no provision for compensating physiological movement using the treatment couch in real-time. In this paper, a real-time couch tracking control technique is presented together with experimental results in tumor motion compensation in four dimensions (superior-inferior, lateral, anterior-posterior, and time). To implement real-time couch motion for tracking, a novel control system for the treatment couch was developed. The primary functional requirements for this novel technique were: (a) the treatment couch should maintain all previous/normal features for patient setup and positioning, (b) the new control system should be used as a parallel system when tumor tracking would be deployed, and (c) tracking could be performed in a single direction and/or concurrently in all three directions of the couch motion (longitudinal, lateral, and vertical). To the authors’ best knowledge, the implementation of such technique to a regular treatment couch for tumor tracking has not been reported so far. To evaluate the performance of the tracking couch, we investigated the mechanical characteristics of the system such as system positioning resolution, repeatability, accuracy, and tracking performance. Performance of the tracking system was evaluated using dosimetric test as an endpoint. To investigate the accuracy of real-time tracking in the clinical setting, the existing clinical treatment couch was replaced with our experimental couch and the linear accelerator was used to deliver 3D conformal radiation therapy (3D-CRT) and intensity modulated radiation therapy (IMRT) treatment plans with and without tracking. The results of radiation dose distribution from these two sets of experiments were compared and presented here. Results: The mechanical accuracies were 0.12, 0.14, and 0.18 mm in X, Y, and Z directions. The repeatability of the desired motion was within ±0.2 mm. The differences of central axis dose between the 3D-CRT stationary plan and two tracking plans with different motion trajectories were 0.21% and 1.19%. The absolute dose differences of both 3D tracking plans comparing to the stationary plan were 1.09% and 1.20%. Comparing the stationary IMRT plan with the tracking IMRT plan, it was observed that the central axis dose difference was ?0.87% and the absolute difference of both IMRT plans was 0.55%. Conclusions: The experimental results revealed that the treatment couch could be successfully used for real-time tumor tracking with a high level of accuracy. It was demonstrated that 4D tumor tracking was feasible using existing couch with implementation of appropriate tracking methodology and with modifications in the control system.

Buzurovic, I.; Yu, Y.; Werner-Wasik, M.; Biswas, T.; Anne, P. R.; Dicker, A. P.; Podder, T. K.

2012-01-01

329

Experimental Energy Levels of HD18O and D_218O  

Microsoft Academic Search

Extended sets of experimental energy levels of HD18O and D_218O have been obtained as the result of the analysis of recent high-resolution spectra and previously reported data. Spectra of the enriched by deuterium and oxygen-18 water samples were recorded with a Bruker IFS 120HR spectrometer at room temperature in the 1000 - 9200 cm-1 range a,b for this purpose. The

S. N. Mikhailenko; O. V. Naumenko; S. A. Tashkun; A.-W. Liu; S.-M. Hu

2010-01-01

330

Experimental X-ray attenuation coefficients at low photon energies for substances of medical importance.  

PubMed

Recent experimental values of X-ray mass attenuation coefficients for the elements zota = 6 to zota = 18 in the energy range from 4 to 25 keV suggest improvements to the data set presented in the ICRU Report 17. The results are, however, in excellent agreement with the theoretical data of Storm and Israel (1970). Values of mass attenuation coefficient for these elements and for a selection of materials of medical and biological importance are presented. PMID:1202514

Millar, R H

1975-11-01

331

Lateral and axial resolutions of an angle-deviation microscope for different numerical apertures: experimental results  

NASA Astrophysics Data System (ADS)

This paper presents a study of the lateral and axial resolutions of a transmission laser-scanning angle-deviation microscope (TADM) with different numerical aperture (NA) values. The TADM is based on geometric optics and surface plasmon resonance principles. The surface height is proportional to the phase difference between two marginal rays of the test beam, which is passed through the test medium. We used common-path heterodyne interferometry to measure the phase difference in real time, and used a personal computer to calculate and plot the surface profile. The experimental results showed that the best lateral and axial resolutions for NA = 0.41 were 0.5 ?m and 3 nm, respectively, and the lateral resolution breaks through the diffraction limits.

Chiu, Ming-Hung; Lai, Chin-Fa; Tan, Chen-Tai; Lin, Yi-Zhi

2011-03-01

332

Experimental Results from Droop Compensation for the High Voltage Converter Modulators  

SciTech Connect

The High Voltage Convertor Modulators are used to power the RF klystrons used throughout the linear accelerator at the Spallation Neutron Source. The output voltage of the modulator has significant voltage droop and ripple which, combined with low level RF system limitations, affect performance and stability of the accelerator cavities. In conjunction with the progress in the development of the new controller, different modulation techniques were implemented and studied on the test modulator. This paper discusses experimental results from implementation of different modulation schemes has on the modulator output voltage pulse. Thermal measurements were carried out to determine the effect of these modulations schemes on long term reliability of the modulator. Future plans are also discussed.

Patel, Gunjan P [ORNL; Anderson, David E [ORNL; Peplov, Vladimir V [ORNL; Saethre, Robert B [ORNL; Solley, Dennis J [ORNL; Wezensky, Mark W [ORNL

2013-01-01

333

A scattering and absorption identity for metamaterials: Experimental results and comparison with theory  

NASA Astrophysics Data System (ADS)

A dispersion relation for the combined effect of scattering and absorption of electromagnetic waves is presented for a large class of linear and passive material models. By invoking the optical theorem, the result states that the extinction cross section integrated over all frequencies is equal to the static limit of the extinction volume. The present paper focuses on an attempt to experimentally verify this sum rule by measuring the monostatic radar cross section of a fabricated sample of metamaterial. In particular, the paper utilizes the idea that, for a specific class of targets, the scattered fields in the forward and backward directions are identical. It is concluded that the theoretical findings are in good agreement with measurements performed in the frequency range [3.2,19.5] GHz.

Sohl, C.; Larsson, C.; Gustafsson, M.; Kristensson, G.

2008-03-01

334

Experimental Results of Growth and Breakdown Mechanisms in the Final Stage of a Pseudospark Discharge  

NASA Astrophysics Data System (ADS)

The Pseudospark Transient Hollow Cathode Discharge (THCD) is a high-voltage low-pressure discharge, which is characterized by an axial hollow cathode electrode. This work presents optical and electric experimental diagnostics in the final stage of THCD in Hydrogen gas at working pressure between 100 mTorr and 250 mTorr. The characteristic signals of the electron and ion beam emission, growing plasma diagnosed by means of the H? light emission at 656 nm from a point behind the cathode aperture, and the arrival to the cathode of the moving virtual anode are temporal and spatial correlated with the ICCD image of the growing plasma in the Hollow Cathode Region (HCR), and compared with our previous results. A performed statistical method lead us to suggest a sequence of ionization growth events which is analyzed to understand the mechanisms involved in the final stages just before breakdown.

Zambra, M.; Moreno, J.; Soto, L.; Rosales, L.

2003-06-01

335

Physical model and experimental results of cathode erosion related to power supply ripple  

NASA Astrophysics Data System (ADS)

This paper discusses the physical effects of power supply ripple on cathode erosion and cathode arc attachment in a water-cooled, 30 kW nitrogen arcjet. Experimental results are presented for 2 percent thoriated tungsten, which show that the long-term cathode erosion rate is a decreasing function of current ripple over the range 1-13 percent. Above this range, the cathode discharge becomes unstable, and the erosion rate rapidly increases. A qualitative model of this effect is given in terms of a magnetically induced radial motion of the arc column, and an overall increase in the cathode spot radius due to the higher peak current associated with higher ripple. The most important effect of power supply ripple is therefore shown to be its ability to collectively drive the cathode attachment away from the cathode center. This leads to an increase in the cathode attachment area, and a subsequent decrease in the cathode erosion rate.

Harris, W. J.; O'Hair, E. A.; Hatfield, L. L.; Kristiansen, M.

1992-07-01

336

Flapping counter torque (FCT) in animal flight: Experimental results and mathematical models  

NASA Astrophysics Data System (ADS)

From our previous studies on a range of insects from fruit flies to cockatoos during fast yaw turning maneuvers (body saccades), we found that body rotation causes a substantial aerodynamic counter torque, termed as flapping counter-torque (FCT), which acts in the opposite direction of turning. In this study, we show that FCT exists in all roll, pitch and yaw axes and are linearly dependent on the flapping frequency and rotational velocity, respectively. We measured the FCTs systematically (by varying wing beat frequency and body turning velocity) on a pair of dynamically scaled robotic model wings. Furthermore, we developed mathematical FCT models based on quasi-steady analysis for roll, pitch and yaw axes. The results show that the experimental data matches the prediction of the analytical models. FCT induced passive damping accounts for a large part of the deceleration in saccade of animal flight, and implies passive rotational stability of the angular velocity dynamics in flapping flight.

Cheng, Bo; Deng, Xinyan

2009-11-01

337

Fault induction dynamic model, suitable for computer simulation: Simulation results and experimental validation  

NASA Astrophysics Data System (ADS)

The study of induction motor behavior under not normal conditions and the ability to detect and predict these conditions has been an area of increasing interest. Early detection and diagnosis of incipient faults are desirable for interactive evaluation over the running condition, product quality guarantee, and improved operational efficiency of induction motors. The main difficulty in this task is the lack of accurate analytical models to describe a faulty motor. This paper proposes a dynamic model to analyze electrical and mechanical faults in induction machines and includes net asymmetries and load conditions. The model permits to analyze the interactions between different faults in order to detect possible false alarms. Simulations and experimental results were performed to confirm the validity of the model.

Baccarini, Lane Maria Rabelo; de Menezes, Benjamim Rodrigues; Caminhas, Walmir Matos

2010-01-01

338

Pore-pressure influence in the poroelastic behavior of rocks: Experimental studies and results  

SciTech Connect

The influence of pore pressure on the elastic strain of rocks is basic to reservoir compaction and subsidence problems and in reservoir engineering and environment studies. Biot's coefficient is an important parameter used to determine the influence of pore pressure on rock deformation. This paper presents measurements of Biot's coefficient on limestone samples and interprets these measurements. The coefficients used in poroelastic studies first are defined as Biot's coefficient and compressibility coefficients proposed by Zimmerman. Then, the experimental apparatus and procedures used to measure these coefficients are described. Finally, the results, which confirm the theoretical framework of poroelasticity, are presented and discussed. The compressibility coefficients and Biot's coefficient increase with porosity according to a law that is formally similar to a Hashin-Shtrickman's type law. For porosities in the 4.5% to 23% range, Biot's coefficient increases from 0.34 to 0.83.

Laurent, J.; Bouteca, M.J.; Sarda, J.P.; Bary, D. (Inst. Francais du Petrole, Rueil-Malmaison (France))

1993-06-01

339

Preliminary experimental results on studying possibility of variable mass liner (VML) formation  

SciTech Connect

The main objective of the present experiment was to study the formation process and initial stage of acceleration of a variable-mass plasma liner (VML). The method is based on magnetic acceleration of a liner with the mass reduced during such acceleration. The experiment was carried out on February 16 at VNIIEF. This report describes the results of measurements obtained in the experiment and preliminary analysis of the results characterizing operation of the test facility main units: helical EMG; 5-module disk EMG 400 mm in diameter (DEMG); ponderomotive unit (PU) with a cylindric condensed liner and a special tooth-cutoff. The first part of the report presents measurement results obtained on the VNIIEF`s diagnostic equipment that are compared with those obtained by American specialists on their diagnostic equipment. Information submitted by American specialists is included in part 2 of this report. The second part of the report presents preliminary computational-theoretic analysis of the main measured results describing operation of DEMG TL system in the experiment; experimental data are compared with theoretical ones obtained before and after the experiment. But more emphasis is placed on the data preliminary analysis indicating that in the experiment a variable mass liner is formed (VML or plasma bubble).

NONE

1995-12-31

340

First experimental results of the ^33S(?,p)^36Cl cross section for production in the early Solar System  

NASA Astrophysics Data System (ADS)

The existence in the early Soalr System (ESS) of the now extinct ^36Cl (t1/2 = 3.01 x 10^5 yr) has been determined from correlation between isotopic enrichment of its daughter isotope, ^36S, and Cl abundance in meteorites. The relatively high inferred initial Solar System ^36Cl/Cl ratio strongly suggests that ^36Cl was produced in the ESS by bombardment of solar energetic particles on gas and dust in the protoplanetary disc. However, no experimental data are currently available for the relevant production reactions cross sections. Instead, models of ESS production use Hauser-Feshbach approximations. The ^33S(?,p)^36Cl reaction is calculated to have the largest cross section at bombardment energies < 5 MeV/A. Here we report first results of a measurement of the averaged reaction cross section in the energy range 1.93- 1.95 MeV/A. Our result, 191 ± 33 mb (1?), is significantly higher than results of previous calculations, 102 and 34 mb.

Bowers, Matthew; Collon, Philippe; Kashiv, Yoav; Bauder, William; Chamberlin, Karen; Lu, Wenting; Robertson, Daniel; Schmitt, Christopher

2011-10-01

341

Using leg muscles as shock absorbers: theoretical predictions and experimental results of drop landing performance.  

PubMed

The use of muscles as power dissipators is investigated in this study, both from the modellistic and the experimental points of view. Theoretical predictions of the drop landing manoeuvre for a range of initial conditions have been obtained by accounting for the mechanical characteristics of knee extensor muscles, the limb geometry and assuming maximum neural activation. Resulting dynamics have been represented in the phase plane (vertical displacement versus speed) to better classify the damping performance. Predictions of safe landing in sedentary subjects were associated to dropping from a maximum (feet) height of 1.6-2.0 m (about 11 m on the moon). Athletes can extend up to 2.6-3.0 m, while for obese males (m = 100 kg, standard stature) the limit should reduce to 0.9-1.3 m. These results have been calculated by including in the model the estimated stiffness of the 'global elastic elements' acting below the squat position. Experimental landings from a height of 0.4, 0.7, 1.1 m (sedentary males (SM) and male (AM) and female (AF) athletes from the alpine ski national team) showed dynamics similar to the model predictions. While the peak power (for a drop height of about 0.7 m) was similar in SM and AF (AM shows a +40% increase, about 33 W/kg), AF stopped the downward movement after a time interval (0.219 +/- 0.030 s) from touch-down 20% significantly shorter than SM. Landing strategy and the effect of anatomical constraints are discussed in the paper. PMID:9857837

Minetti, A E; Ardigò, L P; Susta, D; Cotelli, F

1998-12-01

342

Experimental results of neutron fluence outside an iron shield in the forward direction  

SciTech Connect

Analyses of both lateral shielding measurements and Monte Carlo calculations for beam stop geometry for incident hadrons at energies between 10 GeV and 10 TeV suggests that the dose equivalent can be represented by the expression H = H{sub 0}(E)e{sup -r/{lambda}}/r{sup 2} where H, is the source term, r is the radial distance to the point of interest in the shield, and {lambda} is the effective interaction length, or absorption mean free path. However, unlike the lateral shielding case, there is no similarly simple analytical expression that can be used to describe the on-axis longitudinal cascade development. In this study the results from the measurement in the forward direction of neutron fluence spectra (and the derived quantity dose equivalent) for 25 to 150 GeV pions incident on an iron beam stop as a function of thickness of iron are presented. The observed dependence of both fluence and dose equivalent on shield thickness and hadron energy was then quantified in terms of an expression in which a build up factor as well as an attenuation term was included. On the basis of this analysis the conversion factor from fluence to dose equivalent was also determined for these forward going neutrons. This work represents the first systematic study at an high energy accelerator of the depth dependence of neutron fluence in longitudinal shielding.

Torres, M.M.C. [Argonne National Lab., IL (United States); Elwyn, A.J. [Fermi National Accelerator Lab., Batavia, IL (United States); Fein, D.; James, E.; Johns, K. [Arizona Univ., Tucson, AZ (United States); Davis, W. [Ball State Univ., Muncie, IN (United States); Ciampa, D.P. [Minnesota Univ., Minneapolis, MN (United States); Mierkiewicz, E. [Northern Illinois Univ., De Kalb, IL (United States)

1996-09-01

343

PROSPERO: online prediction of crystallographic success from experimental results and sequence  

PubMed Central

The growth of diffracting crystals from purified proteins is often a major bottleneck in determining structures of biological and medical interest. The PROSPERO web server, http://skuld.bmsc.washington.edu/prospero, is intended both to provide a means of organizing the potentially large numbers of experimental characterizations measured from such proteins, and to provide useful guidance for structural biologists who have succeeded in purifying their target protein but have reached an impasse in the difficult and poorly understood process of turning purified protein into well diffracting crystals. These researchers need to decide which of many possible rescue options are worth pursuing, given finite resources. This choice is even more crucial when attempting to solve high-priority but relatively difficult structures of eukaryotic proteins. The site currently uses the HyGX1 predictor, which was trained and validated on protein samples from pathogenic protozoa (eukaryotes) using results from six types of experiment. PROSPERO allows users to store, analyze and display multiple results for each sample, to group samples into projects, and to share results and predictions with collaborators.

Zucker, Frank H.; Kim, Hae Young; Merritt, Ethan A.

2012-01-01

344

Optimal placement of piezoelectric plates for active vibration control of gas turbine blades: experimental results  

NASA Astrophysics Data System (ADS)

It is well known that the gas turbine blade vibrations can give rise to catastrophic failures and a reduction of the blades life because of fatigue related phenomena[1]-[3] . In last two decades, the adoption of piezoelectric elements, has received considerable attention by many researcher for its potential applicability to different areas of mechanical, aerospace, aeronautical and civil engineering. Recently, a number of studies of blades vibration control via piezoelectric plates and patches have been reported[4]-[6] . It was reported that the use of piezoelectric elements can be very effective in actively controlling vibrations. In one of their previous contributions[7] , the authors of the present manuscript studied a model to control the blade vibrations by piezoelectric elements and validated their results using a multi-physics finite elements package (COMSOL) and results from the literature. An optimal placement method of piezoelectric plate has been developed and applied to different loading scenarios for realistic configurations encountered in gas turbine blades. It has been demonstrated that the optimal placement depends on the spectrum of the load, so that segmented piezoelectric patches have been considered and, for different loads, an optimal combination of sequential and/or parallel actuation and control of the segments has been studied. In this paper, an experimental investigation carried out by the authors using a simplified beam configuration is reported and discussed. The test results obtained by the investigators are then compared with the numerical predictions [7] .

Botta, F.; Marx, N.; Gentili, S.; Schwingshackl, C. W.; Di Mare, L.; Cerri, G.; Dini, D.

2012-03-01

345

General model with experimental validation of electrical resonant frequency tuning of electromagnetic vibration energy harvesters  

NASA Astrophysics Data System (ADS)

This paper presents a general model and its experimental validation for electrically tunable electromagnetic energy harvesters. Electrical tuning relies on the adjustment of the electrical load so that the maximum output power of the energy harvester occurs at a frequency which is different from the mechanical resonant frequency of the energy harvester. Theoretical analysis shows that for this approach to be feasible the electromagnetic vibration energy harvester’s coupling factor must be maximized so that its resonant frequency can be tuned with the minimum decrease of output power. Two different-sized electromagnetic energy harvesters were built and tested to validate the model. Experimentally, the micro-scale energy harvester has a coupling factor of 0.0035 and an untuned resonant frequency of 70.05 Hz. When excited at 30 mg, it was tuned by 0.23 Hz by changing its capacitive load from 0 to 4000 nF its effective tuning range is 0.15 Hz for a capacitive load variation from 0 to 1500 nF. The macro-scale energy harvester has a coupling factor of 552.25 and an untuned resonant frequency of 95.1 Hz and 95.5 Hz when excited at 10 mg and 25 mg, respectively. When excited at 10 mg, it was tuned by 3.8 Hz by changing its capacitive load from 0 to 1400 nF it has an effective tuning range of 3.5 Hz for a capacitive load variation from 0 to 1200 nF. When excited at 25 mg, its resonant frequency was tuned by 4.2 Hz by changing its capacitive load from 0 to 1400 nF it has an effective tuning range of about 5 Hz. Experimental results were found to agree with the theoretical analysis to within 10%.

Zhu, Dibin; Roberts, Stephen; Mouille, Thomas; Tudor, Michael J.; Beeby, Stephen P.

2012-10-01

346

An Experimental Study of Energy-Saving Shoes for Robot as Sagittal Plane Assistance  

NASA Astrophysics Data System (ADS)

In this paper, we propose flexible shoe system to apply passive walking manner to ordinary humanoid biped. In this system, 2DOF (FF & FB) control scheme is used and realize walking with less ankle torque. Besides, this system is consisted as reference modification of position control system, so it can be applicable to most of walking robot even if its joint servo is black box. The effectiveness and characteristics of this system is confirmed by computer simulations and experimental result. The softness of shoe is very important parameter for energy consumption and walking stability. From the discussions of the system, it is said that sagittal plane assistance shoes reduce the energy loss due to the ankle joint friction. Finally, we confirmed the reduction of energy consumption on walking experiment, so we call this system as “energy saving shoes.”

Minakata, Hideaki; Tadakuma, Susumu

347

Experimental setup for low-energy laser-based angle resolved photoemission spectroscopy.  

PubMed

A laser-based angle resolved photoemission (ARPES) system utilizing 6 eV photons from the fourth harmonic of a mode-locked Ti:sapphire oscillator is described. This light source greatly increases the momentum resolution and photoelectron count rate, while reducing extrinsic background and surface sensitivity relative to higher energy light sources. In this review, the optical system is described, and special experimental considerations for low-energy ARPES are discussed. The calibration of the hemispherical electron analyzer for good low-energy angle-mode performance is also described. Finally, data from the heavily studied high T(c) superconductor Bi(2)Sr(2)CaCu(2)O(8+delta) (Bi2212) is compared to the results from higher photon energies. PMID:17552839

Koralek, J D; Douglas, J F; Plumb, N C; Griffith, J D; Cundiff, S T; Kapteyn, H C; Murnane, M M; Dessau, D S

2007-05-01

348

Beryllium Metal I. Experimental Results on Acute Oral Toxicity, Local Skin and Eye Effects, and Genotoxicity  

PubMed Central

The toxicity of soluble metal compounds is often different from that of the parent metal. Since no reliable data on acute toxicity, local effects, and mutagenicity of beryllium metal have ever been generated, beryllium metal powder was tested according to the respective Organisation for Economical Co-Operation and Development (OECD) guidelines. Acute oral toxicity of beryllium metal was investigated in rats and local effects on skin and eye in rabbits. Skin-sensitizing properties were investigated in guinea pigs (maximization method). Basic knowledge about systemic bioavailability is important for the design of genotoxicity tests on poorly soluble substances. Therefore, it was necessary to experimentally compare the capacities of beryllium chloride and beryllium metal to form ions under simulated human lung conditions. Solubility of beryllium metal in artificial lung fluid was low, while solubility in artificial lysosomal fluid was moderate. Beryllium chloride dissolution kinetics were largely different, and thus, metal extracts were used in the in vitro genotoxicity tests. Genotoxicity was investigated in vitro in a bacterial reverse mutagenicity assay, a mammalian cell gene mutation assay, a mammalian cell chromosome aberration assay, and an unscheduled DNA synthesis (UDS) assay. In addition, cell transformation was tested in a Syrian hamster embryo cell assay, and potential inhibition of DNA repair was tested by modification of the UDS assay. Beryllium metal was found not to be mutagenic or clastogenic based on the experimental in vitro results. Furthermore, treatment with beryllium metal extracts did not induce DNA repair synthesis, indicative of no DNA-damaging potential of beryllium metal. A cell-transforming potential and a tendency to inhibit DNA repair when the cell is severely damaged by an external stimulus were observed. Beryllium metal was also found not to be a skin or eye irritant, not to be a skin sensitizer, and not to have relevant acute oral toxic properties.

Strupp, Christian

2011-01-01

349

Responses of Tundra Ecosystems to Environmental Change: Observational and Experimental Results  

NASA Astrophysics Data System (ADS)

Evidence of environmental changes due to human-enhanced climate warming continues to accumulate from polar regions. Responses in tundra and taiga ecosystems to climate changes have been variable because of the wide range in process response rates, from metabolic processes to adjustments in ecosystem carbon balance, and the variability in environmental settings across local to regional scales. For example, strong increases in rates of plant growth and changes in species composition and abundance have been observed in parts of the Low Arctic, but very little change has been measured in high arctic tundra. A dramatic increase in the cover of deciduous shrubs in areas of the western North American Arctic is predicted to result in positive feedbacks to soil temperature, through increased surface roughness and snow depth, and to atmospheric heating by reducing albedo. Increased shrub cover has also been found in long-term experimental warming studies conducted throughout the tundra biome as part of the International Tundra Experiment (ITEX). Warming is also affecting the carbon balance of tundra and taiga, which hold 25% of the soil carbon of global terrestrial ecosystems. However, trajectories of these changes are largely unknown for most northern systems, and differ because of initial conditions of the carbon and nutrient economy. Over the longer-term, the positive increases in plant growth may be constrained by negative feedbacks to nutrient cycling, as increases in C:N ratios of plant litter slow the release of nitrogen to soils. However, nitrogen availability has been shown to increase in response to short-term warming. In this presentation, I will review the responses of tundra ecosystems to climate variability and change, both through observational and experimental studies.

Henry, G. H.

2004-05-01

350

Phase-space analysis and experimental results for secondary focusing at X-ray beamlines  

SciTech Connect

Micro-focusing optical devices at synchrotron beamlines usually have a limited acceptance, but more flux can be intercepted if such optics are used to focus secondary sources created by the primary optics. Flux throughput can be maximized by placing the secondary focusing optics close to or exactly at the secondary source position. However, standard methods of beamline optics analysis, such as the lens equation or matching the mirror surface to an ellipse, work poorly when the source-to-optics distance is very short. In this paper the general characteristics of the focusing of beams with Gaussian profiles by a 'thin lens' are analysed under the paraxial approximation in phase space, concluding that the focusing of a beam with a short source-to-optics distance is distinct from imaging the source; slope errors are successfully included in all the formulas so that they can be used to calculate beamline focusing with good accuracy. A method is also introduced to use the thin-lens result to analyse the micro-focusing produced by an elliptically bent trapezoid-shaped Kirkpatrick-Baez mirror. The results of this analysis are in good agreement with ray-tracing simulations and are confirmed by the experimental results of the secondary focusing at the 18-ID Bio-CAT beamline (at the APS). The result of secondary focusing carried out at 18-ID using a single-bounce capillary can also be explained using this phase-space analysis. A discussion of the secondary focusing results is presented at the end of this paper.

Huang, Rong; Meron, Mati; Kujala, Naresh; Barrea, Raul A. (IIT); (UC); (HWMRI)

2011-11-17

351

Oxygen diffusion in basalt and andesite melts: experimental results and discussion of chemical versus tracer diffusion  

NASA Astrophysics Data System (ADS)

Chemical diffusion coefficients for oxygen in melts of Columbia River basalt (Ice Harbor Dam flow) and Mt. Hood andesite have been determined at 1 atm. The diffusion model is that of sorption or desorption of oxygen into a sphere of uniform initial concentration from a constant and semi-infinite atmosphere. The experimental design utilizes a thermogravimetric balance to monitor the rate of weight change arising from the response of the sample redox state to an imposed fO2. Oxygen diffusion coefficients are approximately an order-ofmagnitude greater for basaltic melt than for andesitic melt. At 1260° C, the oxygen diffusion coefficients are: D=1.65×10-6cm2/s and D=1.43×10-7cm2/s for the basalt and andesite melts, respectively. The high oxygen diffusivity in basaltic melt correlates with a high ratio of nonbridging oxygen/tetrahedrally coordinated cations, low melt viscosity, and high contents of network-modifying cations. The dependence of the oxygen diffusion coefficient on temperature is: D=36.4exp(-51,600±3200/ RT)cm2/s for the basalt and D=52.5exp(-60,060±4900/ RT)cm2/s for the andesite ( R in cal/deg-mol; T in Kelvin). Diffusion coefficients are independent of the direction of oxygen diffusion (equilibrium can be approached from extremely oxidizing or reducing conditions) and thus, melt redox state. Characteristic diffusion distances for oxygen at 1260° C vary from 10-2 to 102 m over the time interval of 1 to 106 years. A compensation diagram shows two distinct trends for oxygen chemical diffusion and oxygen tracer diffusion. These different linear relationships are interpreted as supporting distinct oxygen transport mechanisms. Because oxygen chemical diffusivities are generally greater than tracer diffusivities and their Arrhenius activation energies are less, transport mechanisms involving either molecular oxygen or vacancy diffusion are favored.

Wendlandt, Richard F.

1991-10-01

352

Performances and first experimental results of BACH, the beamline for dichroism and scattering experiments at ELETTRA  

SciTech Connect

BACH, the new soft x-ray beamline for polarization dependent experiments at the Italian synchrotron radiation facility ELETTRA, has been commissioned, characterized and opened to external users. Based on two APPLE II undulators, it covers an energy range between 35 eV and 1600 eV with the control of the light polarization. The monochromator works either in high resolution or high flux mode. Resolving powers of 16000 at 50 eV, 12000 at 90 eV, more than 12000 at 400 eV, 15000 at 534 eV and 6600 at 867 eV have been achieved with the three high resolution gratings. The resolving powers of the high flux grating, which covers the 290 - 1600 eV range, have been measured reaching 7000 at 400 eV and 2200 at 867 eV. The fluxes, in the high resolution mode, range between 4{center_dot}1011 photons/s at 125 eV and 2{center_dot}1010 photons/s at about 1100 eV. Using the high flux grating with the best resolution achievable 1.7{center_dot}1011 photons/s impinge on the sample at 900 eV. Two branches are installed after the monochromator allowing the set-up of two different experimental stations. One of them, besides several facilities for surface preparation and analysis, hosts a compact inelastic soft x-ray spectrometer (ComIXS) dedicated to x-ray emission experiments exploiting the small spot (10 {mu}m in the vertical direction) on the sample. The other branch hosts a liquid helium cryostat equipped with a superconducting coil to perform absorption and transmission experiments with temperatures down to 2 K and magnetic field up to {+-}7 T.

Zangrando, M.; Zacchigna, M.; Bondino, F. [Laboratorio TASC-INFM, S.S. 14 Km 163.5 in Area Science Park, 34012 Trieste (Italy); Finazzi, M. [INFM - Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milan (Italy); Pardini, T. [Applied Physics department - Stanford University, 316 Via Pueblo Mall, Stanford, CA 94305 (United States); Plate, M. [Dipartimento di Fisica 'A. Volta', Universita di Pavia, Via Bassi 6, 27100 Pavia (Italy); Rochow, R.; Cocco, D. [Sincrotrone Trieste ScpA, S.S. 14 Km 163.5 in Area Science Park, 34012 Trieste (Italy); Parmigiani, F. [Laboratorio TASC-INFM, S.S. 14 Km 163.5 in Area Science Park, 34012 Trieste (Italy); Dipartimento di Matematica e Fisica, Universita Cattolica del Sacro Cuore, Via Musei 41, 25121 Brescia (Italy)

2004-05-12

353

Experimental and modeling results of creep-fatigue life of Inconel 617 and Haynes 230 at 850 °C  

NASA Astrophysics Data System (ADS)

Creep-fatigue testing of Ni-based superalloy Inconel 617 and Haynes 230 were conducted in the air at 850 °C. Tests were performed with fully reversed axial strain control at a total strain range of 0.5%, 1.0% or 1.5% and hold time at maximum tensile strain for 3, 10 or 30 min. In addition, two creep-fatigue life prediction methods, i.e. linear damage summation and frequency-modified tensile hysteresis energy modeling, were evaluated and compared with experimental results. Under all creep-fatigue tests, Haynes 230 performed better than Inconel 617. Compared to the low cycle fatigue life, the cycles to failure for both materials decreased under creep-fatigue test conditions. Longer hold time at maximum tensile strain would cause a further reduction in both material creep-fatigue life. The linear damage summation could predict the creep-fatigue life of Inconel 617 for limited test conditions, but considerably underestimated the creep-fatigue life of Haynes 230. In contrast, frequency-modified tensile hysteresis energy modeling showed promising creep-fatigue life prediction results for both materials.

Chen, Xiang; Sokolov, Mikhail A.; Sham, Sam; Erdman, Donald L., III; Busby, Jeremy T.; Mo, Kun; Stubbins, James F.

2013-01-01

354

Experimental and modeling results of creep fatigue life of Inconel 617 and Haynes 230 at 850 C  

SciTech Connect

Creep fatigue testing of Ni-based superalloy Inconel 617 and Haynes 230 were conducted in the air at 850 C. Tests were performed with fully reversed axial strain control at a total strain range of 0.5%, 1.0% or 1.5% and hold time at maximum tensile strain for 3, 10 or 30 min. In addition, two creep fatigue life prediction methods, i.e. linear damage summation and frequency-modified tensile hysteresis energy modeling, were evaluated and compared with experimental results. Under all creep fatigue tests, Haynes 230 performed better than Inconel 617. Compared to the low cycle fatigue life, the cycles to failure for both materials decreased under creep fatigue test conditions. Longer hold time at maximum tensile strain would cause a further reduction in both material creep fatigue life. The linear damage summation could predict the creep fatigue life of Inconel 617 for limited test conditions, but considerably underestimated the creep fatigue life of Haynes 230. In contrast, frequency-modified tensile hysteresis energy modeling showed promising creep fatigue life prediction results for both materials.

Chen, Xiang [ORNL; Sokolov, Mikhail A [ORNL; Sham, Sam [ORNL; ERDMAN III, DONALD L [ORNL; Busby, Jeremy T [ORNL; Mo, Kun [ORNL; Stubbins, James [ORNL

2013-01-01

355

The benefit of time-of-flight in PET imaging: Experimental and clinical results  

PubMed Central

Significant improvements have made it possible to add the technology of time-of-flight (TOF) to improve PET imaging, particularly for oncology applications. The goals of this work were to investigate the benefits of TOF in experimental phantoms and to determine how these benefits translate into improved performance for patient imaging. Methods The Gemini TF scanner (Philips Medical Systems) used in this study is a fully 3D scanner and utilizes the scintillator LYSO with a system timing resolution of ~600 ps. The data are acquired in list-mode and reconstructed with an ML-EM algorithm; the system model includes the TOF kernel and corrections for attenuation, detector normalization, randoms, and scatter. The scatter correction is an extension of the modelbased single-scatter simulation to include the time domain. Phantom measurements to study the benefit of TOF include 27-cm and 35-cm diameter distributions with spheres ranging in size from 10 mm to 37 mm. To assess the benefit of TOF PET for clinical imaging, patient studies are quantitatively analyzed. Results The lesion phantom studies demonstrate the improved contrast of the smallest spheres with TOF compared to non-TOF and also confirm the faster convergence of contrast with TOF. These gains are evident from visual inspection of the images, as well as a quantitative evaluation of contrast recovery of the spheres and noise in the background. The gains with TOF are higher for larger objects. These results correlate with patient studies in which lesions are seen more clearly and with higher uptake at comparable noise for TOF than with non-TOF. Conclusion TOF leads to a better contrast vs. noise trade-off than non-TOF but one that is difficult to quantify in terms of a simple sensitivity gain improvement: a single gain factor for TOF improvement does not include the increased rate of convergence with TOF, nor does it consider that TOF may converge to a different contrast than non-TOF. The experimental phantoms results agree with those of prior simulations and help explain the improved image quality with TOF for patient oncology studies.

Karp, Joel S.; Surti, Suleman; Daube-Witherspoon, Margaret E.; Muehllehner, Gerd

2009-01-01

356

Experimental and theoretical high energy physics research. [UCLA  

SciTech Connect

Progress in the various components of the UCLA High-Energy Physics Research program is summarized, including some representative figures and lists of resulting presentations and published papers. Principal efforts were directed at the following: (I) UCLA hadronization model, PEP4/9 e{sup +}e{sup {minus}} analysis, {bar P} decay; (II) ICARUS and astroparticle physics (physics goals, technical progress on electronics, data acquisition, and detector performance, long baseline neutrino beam from CERN to the Gran Sasso and ICARUS, future ICARUS program, and WIMP experiment with xenon), B physics with hadron beams and colliders, high-energy collider physics, and the {phi} factory project; (III) theoretical high-energy physics; (IV) H dibaryon search, search for K{sub L}{sup 0} {yields} {pi}{sup 0}{gamma}{gamma} and {pi}{sup 0}{nu}{bar {nu}}, and detector design and construction for the FNAL-KTeV project; (V) UCLA participation in the experiment CDF at Fermilab; and (VI) VLPC/scintillating fiber R D.

Not Available

1992-01-01

357

Polycrystalline Ge detectors integrated on SOI waveguide: device modeling and experimental results  

NASA Astrophysics Data System (ADS)

Integration of near infrared (NIR) photodetectors on a silicon substrate is a key step for the fabrication of an all silicon based NIR transceiver. To this extent, polycrystalline germanium (poly-Ge) technology is attractive due to the low deposition temperature and cost. Poly-Ge detectors demonstrated broad response, covering the whole NIR spectrum to 1.55 micron, fast, subnanosecond, speed and excellent versatility. In this work we present our recent results on the integration of a poly-Ge photodetector on a SOI silicon waveguide. The use of a waveguide for light in-coupling is appealing for telecom applications where signal is transported on an optical fibre, but, at the same time, it allows to increase detector responsivity. In fact, in this device the light is absorbed into the thin sensitive layer of the poly-Ge/Si heterojunction in a distributed way, during propagation. This releases the strong constraint of the absorption length being smaller than photocarrier collection length typical of normal incidence photodetectors. In the paper, both design issues and experimental results are reported.

Masini, Gianlorenzo; Colace, Lorenzo; Assanto, Gaetano

2001-05-01

358

Not so simple: a quasi-experimental study of how researchers adjudicate genetic research results  

PubMed Central

Ethicists contend that researchers are obliged to report genetic research findings to individual study participants when they are clinically significant, that is, when they are clinically useful or personally meaningful to participants. Yet whether such standards are well understood and can be consistently applied remains unknown. We conducted an international, cross-sectional survey of cystic fibrosis (CF) and autism genetics researchers using a quasi-experimental design to explore factors influencing researchers' judgments. Eighty percent of researchers agreed, in principle, that clinically significant findings should be reported to individual participants. Yet judgments about when a specific finding was considered clinically significant or warranted reporting varied by scientific factors (replication, robustness, intentionality, and disease context), capacity of the research team to explain the results, and type of research ethics guidance. Further, judgments were influenced by the researchers' disease community (autism or CF), their primary role (clinical, molecular, statistical) and their beliefs regarding a general reporting obligation. In sum, judgments about the clinical significance of genetic research results, and about whether they should be reported, are influenced by scientific parameters as well as contextual factors related to the specific research project and the individual researcher. These findings call into question the assumption that the conditions under which an obligation to disclose arises are uniformly understood and actionable. Adjudicating the clinical readiness of provisional data may be a responsibility better suited to evaluative experts at arms' length of the provisional data in question, rather than a responsibility imposed upon researchers themselves.

Hayeems, Robin Zoe; Miller, Fiona Alice; Li, Li; Bytautas, Jessica Peace

2011-01-01

359

Benefits of aspect diversity for SAR ATR: fundamental and experimental results  

NASA Astrophysics Data System (ADS)

This paper continues the study reported in Ref. 1 and Ref. 2 trading off the fundamental ATR performance capability (i.e., algorithm-independent) of various SAR design options. The previous papers considered the performance impact of SAR range/cross-range resolution and compared the use of 1-D HRR (high-range-resolution radar) versus 2-D SAR, versus multisensor, 3-D SAR. The work reported here extends the SAR and HRR results of Ref. 2 to include aspect diversity in the SAR measurements. We show that SAR and HRR are benefited by multi-aspect measurements mostly because multiple views add diversity: poorer views benefit from having better views combined in a multi-aspect classifier. Finally, as a proof of concept, multi-aspect diversity is incorporated into an existing SAR ATR classifier; performance of an MSTAR 10-class MSE classifier is shown to improve substantially. A major tenet is verified by the experimental results: added measurement domains, such as aspect diversity, which separate the target signature vectors in the observation space, make it easier to obtain better target classification, enhanced false- alarm rejection, and robustness to unknown statistics.

Brendel, Gary F.; Horowitz, Larry L.

2000-08-01

360

Experimental results of phase retrieval with reduced noise using inline digital holography and an iterative method  

NASA Astrophysics Data System (ADS)

Digital holographic microscopy is a method used to retrieve microscopic phase objects. However, the limited CCD bandwidth, used to record the hologram, and the aberrations of imaging lens add some noise into the retrieval process. In this context, the use of referenceless on axis digital holography is highly convenient due to the simplification of the required optical setup. However, the amount of noise, due to the conjugate and zero-order terms in the holograms tend to increase, because these hologram terms are overlapped with the signal term. We propose to enclose the object in a pupil and use this information to obtain an approximation of the object phase. This approximation is used in an iterative method, where the recovered field is cleaned from the conjugate and zero order hologram terms. Moreover, we show that the distortion introduced by loss of high frequency information, in the retrieval process, can be compensated with the iterative method. The simulation of this method had been proved with good results and they present a fast convergence of the algorithm. In this work we present the first experimental results applying this method.

Arrizón, Victor; Cruz, Maria-Luisa

2011-08-01

361

Using the Viking biology experimental results to obtain chemical information about Martian regolith  

NASA Astrophysics Data System (ADS)

Although initially formulated as biology experiments, most of the results produced by the Viking Labeled Release (LR), Gas Exchange (GEX), and Pyrolytic Release (PR) experiments have been reproduced by chemical means. The experiments do not need more study as 'biological' phenomena, but they do deserve much more careful consideration from a chemical viewpoint. They are the only 'wet-chemical' experiments that scientists have performed on another planet, but they have not found very general use as sources of scientific information. There is a large set of potentially useful chemical observations, e.g., the three resolvable and precisely measured kinetic components of the release of C-14-labeled gases, the thermal sensitivity and magnitudes of the oxidation reaction(s) of the LR experiments, the kinetics and magnitude of the O2 and CO2 release of the GEX experiments, the thermal sensitivity of the GEX results, the differences between the thermal sensitivity of the GEX and the thermal sensitivity of the LR responses, and the kinetics and magnitudes of the LR successive injection reabsorption effect. It should be possible to test many chemical aspects of hypothetical martian phenomena in experiments using the biology experimental configurations and derive much valuable information by comparisons with the Viking observations.

Plumb, Robert C.

1993-09-01

362

COMPARISON OF EXPERIMENTAL RESULTS TO CFD MODELS FOR BLENDING IN A TANK USING DUAL OPPOSING JETS  

SciTech Connect

Research has been completed in a pilot scale, eight foot diameter tank to investigate blending, using a pump with dual opposing jets. The jets re-circulate fluids in the tank to promote blending when fluids are added to the tank. Different jet diameters and different horizontal and vertical orientations of the jets were investigated. In all, eighty five tests were performed both in a tank without internal obstructions and a tank with vertical obstructions similar to a tube bank in a heat exchanger. These obstructions provided scale models of several miles of two inch diameter, serpentine, vertical cooling coils below the liquid surface for a full scale, 1.3 million gallon, liquid radioactive waste storage tank. Two types of tests were performed. One type of test used a tracer fluid, which was homogeneously blended into solution. Data were statistically evaluated to determine blending times for solutions of different density and viscosity, and the blending times were successfully compared to computational fluid dynamics (CFD) models. The other type of test blended solutions of different viscosity. For example, in one test a half tank of water was added to a half tank of a more viscous, concentrated salt solution. In this case, the fluid mechanics of the blending process was noted to significantly change due to stratification of fluids. CFD models for stratification were not investigated. This paper is the fourth in a series of papers resulting from this research (Leishear, et.al. [1- 4]), and this paper documents final test results, statistical analysis of the data, a comparison of experimental results to CFD models, and scale-up of the results to a full scale tank.

Leishear, R.

2011-08-07

363

Pressurization test results: Bonneville Power Administration Energy Conservation Study  

SciTech Connect

Results are presented of air leakage measurements in 18 single-family detached houses at the Midway substation, Hanford, Washington, performed as part of the Bonneville Power Administration's Energy Conservation Study. The change in energy consumption following various retrofit strategies is compared. Air leakage was measured in each house with the fan pressurization technique, before and after the retrofits were installed. No significant change was found in infiltration rates in those houses receiving either no retrofits or insulation only; and average reduction of 17% in leakage area was found in the houses retrofitted with storm doors and windows. There appears to be great potential for further savings in energy use from reduced infiltration, and the study is being extended to investigate this.

Krinkel, D.L.; Dickeroff, D.J.; Casey, J.; Grimsrud, D.T.

1980-12-01

364

Supersonic Retropropulsion Experimental Results from the NASA Ames 9-x7-Foot Supersonic Wind Tunnel.  

National Technical Information Service (NTIS)

Supersonic retropropulsion was experimentally examined in the Ames Research Center 9x7-Foot Supersonic Wind Tunnel at Mach 1.8 and 2.4. The experimental model, previously designed for and tested in the Langley Research Center Unitary Plan Wind Tunnel at M...

K. T. Edquist M. N. Rhode S. A. Berry

2012-01-01

365

Supersonic Retropropulsion Experimental Results from the NASA Langley Unitary Plan Wind Tunnel.  

National Technical Information Service (NTIS)

A new supersonic retropropulsion experimental effort, intended to provide code validation data, was recently completed in the Langley Research Center Unitary Plan Wind Tunnel Test Section 2 over the Mach number range from 2.4 to 4.6. The experimental mode...

C. J. Player K. T. Edquist M. N. Rhode S. A. Berry

2011-01-01

366

New experimental and simulated results on nuclear media effects in meson photoproduction off nuclei  

Microsoft Academic Search

New experimental approach to study meson photoproduction in nuclei is discussed. It is based on the measurement of the recoil nucleon as a tagger for identification of the initial step of reaction. Propagation of mesons and nucleons within a nucleus is described by the Intra-Nuclear Cascade (INC) model. Simulations and preliminary experimental data for the deuteron target obtained at GRAAL

A. Ignatov; O. Bartalini; V. Bellini; J. P. Bocquet; P. Calvat; M. Capogni; M. Casano; M. Castoldi; A. D’Angelo; J.-P. Didelez; R. Di Salvo; A. Fantini; G. Gervino; F. Ghio; B. Girolami; A. Giusa; M. Guidal; E. Hourany; V. Kouznetsov; R. Kunne; A. Lapik; P. Levi Sandri; A. Lleres; D. Moricciani; A. Mushkarenkov; V. Nedorezov; L. Nicoletti; C. Perrin; D. Rebreyend; F. Renard; N. Rudnev; T. Russew; G. Russo; C. Schaerf; M.-L. Sperduto; M.-C. Sutera; A. Turinge

2008-01-01

367

Kentucky's Experimental Elementary Counselor Program: Results and Recommendations for Marketing Exemplary Practices To Meet KERA Goals.  

ERIC Educational Resources Information Center

This report examines Kentucky's experimental elementary guidance programs, which were funded in 1988 and evaluated in the second year of the 2-year experimental program. In the second year, data were gathered from counselors, teachers, students, and parents; the data are presented in this document. The first section, "Effective Elementary Guidance…

Holcomb, Thomas F.; Latto, Lowell D.

368

Drying of porous media in the presence of gravity: Experimental Results and Pore Network Modeling  

NASA Astrophysics Data System (ADS)

We study the drying of glass bead packings saturated with liquid hexane in predominantly 2D glass cells under environmental conditions to offer insight in the dynamics of the drying process. Our experimental setup allows for the monitoring of the bulk liquid and gas phase distribution patterns, as well as the liquid films that form at the pore walls after the invasion of the bulk gas phase. We are thus able to classify the drying pore space into 3 distinct regions; a far-field completely-wet region, where the pore space is saturated by the bulk liquid hexane; a completely dry region, close to side of the medium open to the ambient environment, that contains only hexane vapors; and finally an intermediate region, located between the first two, that is partially saturated by liquid hexane in the form of liquid films at the walls of the pores and by hexane vapors in the central part of the pore space. Our experiments reveal two distinct drying periods; an early constant drying rate period (CRP), that lasts as long as the film region is contact with the external surface of the medium; and a later falling rate period (FRP) that is related with the development of the completely dry region below the surface. The critical residual hexane saturation that marks the transition between these two regimes is found to be a function of the average bead size in our packings and the incline of the cells with respect to the flat surface, with larger beads and angles closer to the vertical position leading to earlier film detachment times and higher critical saturations. Based on our experimental results we propose a pore network model that accounts for the major transport mechanisms within the porous medium coupled with mass transfer by diffusion through a mass boundary layer over the external surface of the medium. We show that in the limit of a gravity-stabilized percolation front (interface between the completely-wet and film regions) the medium can be treated as a 1D continuum where analytical solutions to the governing equations are derived. We are thus able to obtain results for the drying rates, the critical saturation and the extent of the film region with respect to the various dimensionless numbers that describe the process; the Bond number, a film-based Capillary number and the dimensionless extent of the mass boundary layer.

Yiotis, A. G.; Salin, D.; Tajer, E.; Yortsos, Y.

2011-12-01

369

Experimental comparison of 241Am-Be neutron fluence energy distributions.  

PubMed

(241)Am-Be(alpha,n) neutron sources provide one of the most commonly used neutron fields for routine calibration of neutron sensitive devices. The neutron energy distribution of the IRSN standard (241)Am-Be source was measured in the energy region above 1.65 MeV using a BC501A proton-recoil liquid scintillator. The experimental data were compared to the ISO-recommended neutron energy distribution for an (241)Am-Be source. Some differences in shape were observed, with large variations mainly within the energy interval 3-6 MeV and around 8 MeV. Within the framework of a collaboration between three national metrological institutes (PTB, Germany; NPL, UK and LNE-IRSN, France), the neutron energy distributions of (241)Am-Be sources at each laboratory have been compared. The IRSN-BC501A proton-recoil scintillator was used to measure all the sources. The results show different energy distributions a priori influenced by the origin of the source, i.e. the manufacturing process. The maximum deviation observed for the integral dose equivalent, in the measured BC501A energy range, is within the 4% uncertainty recommended by ISO standard 8529-2 to allow for variations of the neutron spectrum among different (241)Am-Be sources. However, knowledge of the energy distribution of an (241)Am-Be source provides a way to reduce the uncertainty in the dose equivalent rate delivered by such a source. PMID:17510201

Lebreton, L; Zimbal, A; Thomas, D

2007-05-17

370

The Role of Friends' Disruptive Behavior in the Development of Children's Tobacco Experimentation: Results from a Preventive Intervention Study  

PubMed Central

Having friends who engage in disruptive behavior in childhood may be a risk factor for childhood tobacco experimentation. This study tested the role of friends’ disruptive behavior as a mediator of the effects of a classroom based intervention on children’s tobacco experimentation. 433 Children (52% males) were randomly assigned to the Good Behavior Game (GBG) intervention, a universal preventive intervention targeting disruptive behavior, and facilitating positive prosocial peer interactions. Friends’ disruptive behavior was assessed from age 7–10 years. Participants’ experimentation with tobacco was assessed annually from age 10–13. Reduced rates in tobacco experimentation and friends’ disruptive behavior were found among GBG children, as compared to controls. Support for friends’ disruptive behavior as a mediator in the link between intervention status and tobacco experimentation was found. These results remained after controlling for friends’ and parental smoking status, and child ADHD symptoms. The results support the role of friends’ disruptive behavior in preadolescents’ tobacco experimentation.

Huizink, Anja; Vuijk, Patricia

2010-01-01

371

The role of friends' disruptive behavior in the development of children's tobacco experimentation: results from a preventive intervention study.  

PubMed

Having friends who engage in disruptive behavior in childhood may be a risk factor for childhood tobacco experimentation. This study tested the role of friends' disruptive behavior as a mediator of the effects of a classroom based intervention on children's tobacco experimentation. 433 Children (52% males) were randomly assigned to the Good Behavior Game (GBG) intervention, a universal preventive intervention targeting disruptive behavior, and facilitating positive prosocial peer interactions. Friends' disruptive behavior was assessed from age 7-10 years. Participants' experimentation with tobacco was assessed annually from age 10-13. Reduced rates in tobacco experimentation and friends' disruptive behavior were found among GBG children, as compared to controls. Support for friends' disruptive behavior as a mediator in the link between intervention status and tobacco experimentation was found. These results remained after controlling for friends' and parental smoking status, and child ADHD symptoms. The results support the role of friends' disruptive behavior in preadolescents' tobacco experimentation. PMID:20694577

van Lier, Pol A C; Huizink, Anja; Vuijk, Patricia

2011-01-01

372

Cessation of environmentally-assisted cracking in a low-alloy steel: Experimental results  

SciTech Connect

The presence of dissolved metallurgical sulfides in pressure vessel and piping steels has been linked to Environmentally-Assisted Cracking (EAC), a phenomenon observed in laboratory tests that results in fatigue crack growth rates as high as 100 times that in air. Previous experimental and analytical work based on diffusion as the mass transport process has shown that surface cracks that are initially clean of sulfides will not initiate EAC in most applications. This is because the average crack tip velocity would not be sufficiently high to expose enough metallurgical sulfides per unit time and produce the sulfide concentration required for EAC. However, there is a potential concern for the case of a relatively large embedded crack breaking through to the wetted surface. Such a crack would not be initially clean of sulfides, and EAC could initiate. This paper presents the results of a series of experiments conducted on two heats of an EAC susceptible, high-sulfur, low-alloy steel in 243{degrees}C low-oxygen water to further study the phenomenon of EAC persistence at low crack tip velocities. A load cycle profile that incorporated a significant load dwell period at minimum load was used. In one experiment, the fatigue cycling history was such that relatively high crack tip velocities at the start of the experiment produced a persistent case of EAC even when crack tip velocities were later reduced to levels below the EAC initiation velocity. The other series of experiments used initial crack tip velocities that were much lower and probably more realistic. Air precracking of the compact tension specimens produced an initial inventory of undissolved sulfides on the crack flanks that directly simulates the array of sulfides expected from the breakthrough of an embedded crack. In all cases, results showed EAC ceased after several hundred hours of cycling.

Li, Y.Y.

1997-01-01

373

THEORETICAL AND EXPERIMENTAL INVESTIGATION OF ENERGY EXTRACTION FROM ATMOSPHERIC TURBULENCE  

Microsoft Academic Search

Birds frequently use the energy present in atmo- spheric currents to conserve their energy while flying. Although energy in the form of ther- mal updrafts is routinely used by pilots of full- scale and model sailplanes, the energy in atmo- spheric turbulence has not been utilized to its full potential. This paper deals with the design of simple control laws

Chinmay K. Patel; Ilan M. Kroo

374

A 2D optomechanical focused laser spot scanner: analysis and experimental results for microstereolithography  

NASA Astrophysics Data System (ADS)

This paper proposes and analyzes a 2D optomechanical-focused laser spot scanning system (patent pending) which allows uniform intensity focused spot scanning with high speed and high resolution over a large range of scan. Such scanning is useful where variation of focused spot characteristics affects the performance of applications such as micro-/nano-stereolithography, laser micro-machining, scanning optical tweezers, optical scanning microscopy, and so on. Proposed scanning is achieved by using linear movement of mirrors and lens maintaining the alignment of motion and optical axis of laser. Higher speed and high resolution at the same time are achieved by use of two serial double parallelogram flexural mechanisms with mechatronics developed around them. Optical analysis is carried out to demonstrate effectiveness of the proposed system numerically and is further supported by the experimental results. Additional analysis is carried out to demonstrate robustness of the scanner in the case of small misalignment errors incurred in actual practice. Although the proposed scanner is useful in general in several applications mentioned above, discussion in this paper is focused on microstereolithography.

Gandhi, P. S.; Deshmukh, S.

2010-01-01

375

Non-Shock Initiation Model for Plastic Bonded Explosive PBXN-5 and Cast Explosive: Experimental Results  

NASA Astrophysics Data System (ADS)

A damage initiated reaction (DMGIR) computational model is being developed for the CTH shock physics code to predict the response of an explosive to non-shock mechanical insults. The distinguishing feature of this model is the introduction of a damage variable, which relates the evolution of damage to the initiation of reaction in the explosive, and its growth to detonation. The DMGIR model is a complement to the History Variable Reactive Burn (HVRB) model embedded in the current CTH code. Specifically designed experiments are supporting the development, implementation, and validation of the DMGIR numerical approach. PBXN-5 was the initial explosive material used experimentally to develop the DMGIR model. This explosive represents a family of plastically bonded explosives with good mechanical strength and rigid body properties. The model has been extended to cast explosives represented by Composition B. Furthermore, the DMGIR model will extended to predict results of non-shock mechanical insults for moldable plastic explosives such as C4 and PrimaSheet.

Anderson, Mark; Todd, Steven; Caipen, Terry; Jensen, Charlie; Hughs, Chance

2009-06-01

376

Bioimaging and biospectra analysis by means of independent component analysis: experimental results  

NASA Astrophysics Data System (ADS)

Analysis of bioimaging and biospectra data has received increasingly attention in recent years. Here we will present two experimental results based on independent component analysis (ICA): differentiation of superparamagnetic iron oxide (SPIO) nanoparticles used as contrast agents in magnetic resonance imaging (MRI), and differentiation of mixed chemical analytes by surface-enhanced Raman scattering (SERS). The SPIO nanoparticles have been applied extensively as contrast agent in MRI for tracking of stem cells, targeted detection of cancer, due to its biocompatible and biodegradable features. For differentiation of SPIO from the background signal (e.g. interface between air and tissues), the signal voids from multiple sources makes the task very difficult. To solve this problem, we assume that the number of sensors corresponds to the number of acquisitions with different combinations of MR parameters, i.e., longitudinal and transverse relaxation times. For detection of chemical and biological analytes, the SERS approach has drawn more interest because of its high sensitivity. SERS spectra of mixed analytes were acquired at different locations of a silver nanorod array substrate. Due to the nonuniform diffusion and adsorption of the analytes, these spectra have been successfully used to identify the characteristic SERS spectrum of individual analytes. In both the MRI and SERS data, signal source separation (SPIO or mixed chemical analytes from background signal) was performed on a pixel by pixel basis. The ICA was performed by a spatial analysis using the fast ICA method.

Zhao, Qun; Langley, Jason; Lee, Joonsang; Abell, Justin; Zhao, Yiping

2011-05-01

377

Vibrational reduction in integral-damped composite fan blades: experimental results  

NASA Astrophysics Data System (ADS)

The experimental behavior of spinning laminated composite pretwisted plates (turbo-fan blade-like) with small (less than 10% by volume) integral viscoelastic damping patches is investigated. Two different plate sets were examined. The first set investigated tailoring patch locations and definitions to damp specific modes on spinning flat graphite/epoxy plates as a function of rotational speed. The second set investigated damping patch size and location on specific modes of pretwisted (30 degrees) graphite/epoxy plates. The results reveal that: (1) significant amount of damping can be added using a small amount of damping material, (2) the damped plates experienced no failures up to the tested 28,000 g's and 750,000 cycles, (3) centrifugal loads caused an increase in bending frequencies and corresponding reductions in bending damping levels that are proportional to the bending stiffness increase, and (4) the centrifugal loads caused a decrease in torsion natural frequency and increase in damping levels of pretwisted composite plates.

Kosmatka, John B.; Mehmed, Oral

1998-06-01

378

Effectiveness of supported education for individuals with psychiatric disabilities: results from an experimental study.  

PubMed

In recent years post-secondary education has been recognized as a viable option in the psychosocial rehabilitation of individuals with mental illness. This study reports the first evidence of effectiveness of a supported education demonstration project which used an experimental design to compare the effects of different model types. A total of 397 participants were assigned to one of three conditions: group, classroom, and individual (control). At graduation from the program significant differences in program participation rates were found; group members participated most, followed by classroom participants, then those assigned to the individual condition. Also, immediate, intermediate, and long term outcomes were examined. On four immediate outcomes (motivation, satisfaction, enjoyment, and learning) significant participation effects were found (high participants scoring highest, followed by moderate participants, and then non-participants). On two intermediate outcome (empowerment and school efficacy) condition differences were found (classroom scoring highest followed by group, then individual). Although no condition differences were found on behavioral outcomes, the percentage of individuals enrolled in school or vocational education was more than twice that reported at baseline. Overall, the results demonstrated success in engaging participants, affecting self-perceptions, and increasing enrollment in post-secondary education. PMID:9833200

Collins, M E; Bybee, D; Mowbray, C T

1998-12-01

379

C-band SAR results obtained by an experimental airborne SAR sensor  

NASA Astrophysics Data System (ADS)

Described is an airborne experimental SAR currently under development by the DLR. It allows the study of the SAR method and its problems, such as motion error correction and overall system calibration. The sensor is designed to operate aboard a DO 228 aircraft in either L- or C-band. A first series of flight experiments in L-band was completed successfully in spring 1988. The C-band system installation onboard the aircraft was completed in October 1988, and first flight experiments were carried out over test areas in southern Germany. The C-band front-end represents a first step towards an active array. The amount of quantization and saturation noise is minimized by adapting the received-signal power variation to the dynamic range of the A/D converters. Platform-attitude and navigation data are collected and recorded on high-density tape. The ground-based data processing and the results obtained with the radar are examined.

Horn, R.

380

MHD activity in the ISX-B tokamak: experimental results and theoretical interpretation  

SciTech Connect

The observed spectrum of MHD fluctuations in the ISX-B tokamak is clearly dominated by the n=1 mode when the q=1 surface is in the plasma. This fact agrees well with theoretical predictions based on 3-D resistive MHD calculations. They show that the (m=1; n=1) mode is then the dominant instability. It drives other n=1 modes through toroidal coupling and n>1 modes through nonlinear couplings. These theoretically predicted mode structures have been compared in detail with the experimentally measured wave forms (using arrays of soft x-ray detectors). The agreement is excellent. More detailed comparisons between theory and experiment have required careful reconstructions of the ISX-B equilibria. The equilibria so constructed have permitted a precise evaluation of the ideal MHD stability properties of ISX-B. The present results indicate that the high ..beta.. ISX-B equilibria are marginally stable to finite eta ideal MHD modes. The resistive MHD calculations also show that at finite ..beta.. there are unstable resistive pressure driven modes.

Carreras, B.A.; Dunlap, J.L.; Bell, J.D.; Charlton, L.A.; Cooper, W.A.; Dory, R.A.; Hender, T.C.; Hicks, H.R.; Holmes, J.A.; Lynch, V.E.

1982-01-01

381

Experimental results from a preclinical X-ray phase-contrast CT scanner  

PubMed Central

To explore the future clinical potential of improved soft-tissue visibility with grating-based X-ray phase contrast (PC), we have developed a first preclinical computed tomography (CT) scanner featuring a rotating gantry. The main challenge in the transition from previous bench-top systems to a preclinical scanner are phase artifacts that are caused by minimal changes in the grating alignment during gantry rotation. In this paper, we present the first experimental results from the system together with an adaptive phase recovery method that corrects for these phase artifacts. Using this method, we show that the scanner can recover quantitatively accurate Hounsfield units in attenuation and phase. Moreover, we present a first tomography scan of biological tissue with complementary information in attenuation and phase contrast. The present study hence demonstrates the feasibility of grating-based phase contrast with a rotating gantry for the first time and paves the way for future in vivo studies on small animal disease models (in the mid-term future) and human diagnostics applications (in the long-term future).

Tapfer, Arne; Bech, Martin; Velroyen, Astrid; Meiser, Jan; Mohr, Jurgen; Walter, Marco; Schulz, Joachim; Pauwels, Bart; Bruyndonckx, Peter; Liu, Xuan; Sasov, Alexander; Pfeiffer, Franz

2012-01-01

382

Comparison between Simmons's Equations and Quantum Tunneling Experimental Results in A Thin Film  

NASA Astrophysics Data System (ADS)

The theoretical predictions of J.G. Simmons's equations are compared with quantum tunneling experimental results and a discrepancy is found at bias voltage Vb=U/e, where U is the barrier's potential height and e is the electron charge. Specifically, he divided the bias voltage into 2 regions: Vb < U/e and Vb > U/e, and the I -- V characteristics are different in these two regions. The derived equations show a kink on differential conductance dI/dV vs. Vb at Vb=U/e, because starts at this bias the thickness of the insulation film decreases with Vb in addition to the lowering of the barrier's average height. Therefore, the differential conductance decreases more rapidly in the region Vb > U/e than in the region Vb < U/e. However, in tunneling experiment in which Pt is used as conductor and solid neon as insulator, we have not observed such kink even the bias was increased to 4 volts. Our speculation is either 1) there should not be a kink on conductance at Vb=U/e so Simmons's equations need to be modified; 2) the kink should exist but bias voltage is not high enough to observe it in the experiments.

Ma, Lianxi

2012-02-01

383

[Central pain processing and Parkinson's disease. Epidemiology, physiology, and experimental results issuing pain processing].  

PubMed

Parkinson's disease (PD) is caused by degeneration of the dopaminergic neurons in the substantia nigra (SN) and a resulting dysfunction of the nigrostriatal pathways including the basal ganglia. Beside motor symptoms, different types of pain (e.g., dystonic musculoskeletal pain or central pain) occur in a considerable number of patients. In addition, abnormalities in pain processing have been observed in PD patients, which may present as increased pain sensitivity. The pathophysiological mechanisms involved in disturbed pain processing of PD, however, are still poorly understood. The present article gives an overview of the relevant experimental studies, investigating the abnormalities of pain processing in PD by means of electrophysiological [electroencephalography (EEG), sympathetic skin response (SSR)] and psychophysical methods [quantitative sensory testing (QST), RIII reflex threshold]. Based on a review of the literature, it is postulated that dysfunction in endogenous pain inhibition caused by dopaminergic deficiency in the basal ganglia, especially in the striatum, but also in mesolimbic areas is a main pathophysiological mechanism involved in nociceptive abnormalities in PD. PMID:23052966

Priebe, J A; Rieckmann, P; Lautenbacher, S

2012-12-01

384

Experimental and Simulated Results of SiC Microwave Power MESFETs  

NASA Astrophysics Data System (ADS)

A variety of RF and microwave electronic devices can be fabricated from SiC. These SiC-based devices have many properties that make them near ideal for high temperature, high frequency, high power, and radiation hard applications. Progress in SiC bulk and epitaxial layer growth has been rapid in recent years and corresponding progress has been achieved in device fabrication and contact technology. Both 6H- and 4H-SiC substrates are commercially available, and high quality epitaxial layers can be grown. Prototype SiC electronic devices with very good DC and RF performance have been demonstrated and devices such as diodes are commercially available, while RF and high frequency transistors are rapidly approaching the commercialization state. In particular, SiC transistors such as MESFETs (MEtal Semiconductor Field-Effect Transistors) and SITs (Static Induction Transistors) with excellent DC and RF performance have been demonstrated and these devices are being developed for microwave power amplifier and oscillator applications. One of the most promising devices for microwave power applications is the MESFET. In this work the performance of microwave SiC MESFETs is investigated with a simulator that contains a physically based device model. The simulator permits the operation of the device to be examined and optimum device structures to be determined. This, in turn, permits performance capability and limitations to be investigated. The results of the simulations are compared to experimental measurements where possible, and excellent agreement between the simulated and measured data are obtained.

Trew, R. J.

1997-07-01

385

Preparation, conduct, and experimental results of the AVR loss-of-coolant accident simulation test  

SciTech Connect

A loss-of-coolant accident (LOCA) is one of the most severe accidents for a nuclear power plant. To demonstrate inherent safety characteristics incorporated into small high-temperature gas-cooled reactor (HTGR) design, LOCA simulation tests have been conducted at the Arbeitsgemeinschaft Versuchsreaktor (AVR), the German pebble-bed-high-temperature reactor plant. The AVR is the only nuclear power plant ever to have been intentionally subjected to LOCA conditions without emergency cooling. This paper presents the planning and licensing activities including pretest predictions performed for the LOCA test are described, and the conduct of the test and experimental results. The LOCA test was planned to create conditions that would exist if a rapid LOCA occurred with the reactor operating at full power. The test demonstrated this reactor's safe response to an accident in which the coolant escapes from the reactor core and no emergency system is available to provide coolant flow to the core. The test is of special interest because it demonstrates the inherent safety features incorporated into optimized modular HTGR designs. The main LOCA test lasted for 5 days. After the test began, core temperatures increased for {approx}13 h and then gradually and continually decreased as the rate of heat dissipation from the core exceeded the simulated decay power. Throughout the test, temperatures remained below limiting values for the core and other reactor components.

Kruger, K.; Bergerfurth, A.; Burger, S.; Pohl, P.; Wimmers, M. (Arbeitsgemeinschaft Versuchsreaktor AVR GmbH, Duesseldorf (DE)); Cleveland, J.C. (Oak Ridge National Lab., TN (United States))

1991-02-01

386

On the vehicle sideslip angle estimation through neural networks: Numerical and experimental results  

NASA Astrophysics Data System (ADS)

Stability control systems applying differential braking to inner/outer tires are nowadays a standard for passenger car vehicles (ESP, DYC). These systems assume as controlled variables both the yaw rate (usually measured on board) and the sideslip angle. Unfortunately this latter quantity can directly be measured only through very expensive devices however unsuitable for ordinary vehicle implementation and thus it must be estimated. Several state observers eventually adapting the parameters of their reference vehicle models have been developed at the purpose. However sideslip angle estimation is still an open issue. In order to avoid problems concerned with reference model parameters identification/adaptation, a layered neural network approach is proposed in this paper to estimate the sideslip angle. Lateral acceleration, yaw rate, speed and steer angle which can be acquired by ordinary sensors are used as inputs. The design of the neural network and the definition of the manoeuvres constituting the training set have been gained by means of numerical simulations with a 7 d.o.f.s vehicle model. Performance and robustness of the implemented neural network have subsequently been verified by post-processing the experimental data acquired with an instrumented vehicle and referred to several handling manoeuvres (step-steer, power on, double lane change, etc.) performed on various road surfaces. Results generally show a good agreement between the estimated and the measured sideslip angle.

Melzi, S.; Sabbioni, E.

2011-08-01

387

Sediment sorption coefficient measurements for four phthalate esters: Experimental results and model theory  

SciTech Connect

Sediment partition coefficients were measured for four commercial phthalate esters: dihexyl phthalate (DHP), di(2-ethylhexyl) phthalate (DEHP), diisodecyl phthalate (DIDP), and ditridecyl phthalate (DTDP). The experimental procedure was based on the US Environmental Protection Agency (EPA) test Guideline 796.2750, ``Sediment and Soil Adsorption Isotherm.`` Three sediments were used: EPA 8 (0.15% organic carbon), EPA 18 (0.66% organic carbon), and EPA 21 (1.88% organic carbon). The Freundlich equation was used to calculate organic carbon-normalized sediment/water partition coefficients (K{sub oc}), which averaged 5.26 {times} 10{sup 4} {+-} 4.54 {degree} 10{sup 3}; 4.82 {times} 10{sup 5} {+-} 3.52 {times} 10{sup 5}; 2.86 {times} 10{sup 5} {+-} 2.74 {times} 10{sup 5}; and 1.82 {times} 10{sup 6} {+-} 1.05 {times} 10{sup 6} for DHP, DEHP, DIDP, and DTDP, respectively. In general, these K{sub oc} values did not correlate well to either sediment or chemical properties. This lack of correlation suggested that the measured K{sub oc} values are suppressed, potentially as a function of experimental conditions. On the basis of these data, it was decided to investigate the dependence of K{sub oc} on sediment solids concentration and dissolved organic carbon. Analysis of these and earlier reported partition coefficient data indicated that measured K{sub oc} values for phthalate esters obtained in shake-flask experiments exhibited an inverse dependence on solids concentration. These results were consistent with partitioning models that are discussed. Depending on compound hydrophobicity, the particle-corrected K{sub oc} values were from one to three orders of magnitude higher than the measured K{sub oc} values. Therefore, if partition coefficient values obtained by using Test Guideline 796.2750 or similar shake-flask procedures are not corrected for solids effect, the estimates of the sediment pore-water concentration of the chemical is likely to be overestimated.

Williams, M.D.; Adams, W.J. [ABC Laboratories, Columbia, MO (United States); Parkerton, T.F.; Biddinger, G.R. [Exxon Biomedical Sciences, East Millstone, NJ (United States); Robillard, K.A. [Eastman Kodak Co., Rochester, NY (United States)

1995-09-01

388

Experimental and analytical results of a liquid-gas separator in microgravity  

NASA Astrophysics Data System (ADS)

The microgravity phase separator designed and fabricated at Texas A&M University relies on centripetally driven buoyancy forces to form a gas-liquid vortex within a fixed, right-circular cylinder. Two phase flow is injected tangentially along the inner wall of this cylinder. Centripetal acceleration is produced from the intrinsic momentum of the resulting rotating flow and drives the buoyancy process. Gas travels under density gradients through the rotating liquid, eventually forming a gaseous core along the centerline of the cylinder. Gas core stability, the presence of liquid in the air line, and the presence of air in the liquid line determine whether a successful core results. To predict separation failure, these three factors were examined both analytically and empirically with the goal of determining what operating circumstances would generate them. The centripetal acceleration profile was determined from angular velocity measurements taken using a paddle wheel assembly. To aid in understanding the nature of the rotating flow, these results were compared to analytical results provided by solving simplified Navier-Stokes equations. The theoretical velocity profile indicated a linear dependence on radius, which with the experimental data agreed, although two distinctly different slopes were observed. As injection nozzle width increased, the difference between the slopes lessened. For all three nozzles tested, the discontinuity between the linear sections occurred at a radius of approximately 3.8 cm. The maximum centripetal acceleration generated by the flow was greatest for the 0.0635 cm wide, 0.516 cm tall injection nozzle and least for the 0.102 cm wide, 1.02 cm tall injection nozzle. The circumstances leading to carry-under are dictated by the relationship between axial and radial bubble transit times. To determine the radial and axial transit times, the radial velocity profile was solved analytically by relating the buoyancy and drag forces for a 0.0635 cm radius bubble. This velocity profile was then used to produce a numerical solution for the radial transit time. Volumetric flowrate analysis provided the axial velocity and bubble transit time. 33.4, 50.1, 66.8, and 83.5 cm3/s flowrates were tested and only the 33.4 cm3/s flowrate resulted in conditions which would lead to carry under.

Best, Frederick; Ellis, Michael

1999-01-01

389

First Experimental Results from the EU 2 MW Coaxial Cavity Iter Gyrotron Prototype  

NASA Astrophysics Data System (ADS)

The EU is working towards providing 2 MW, coaxial-cavity, CW, 170 GHz gyrotrons for ITER. Their design is based on results from an experimental pre-prototype tube in operation at FZK for several years, having a pulse length of several milliseconds. The first industrial prototype tube is designed for CW operation, but, in a first phase, will be tested out to 1s at the European Gyrotron Test Facility in Lausanne, Switzerland as part of a phased testing/development program (1 s, 60 s, CW). It is known that RF beam profile shaping, stray radiation handling, and collector cooling at these high power levels are three issues for the gyrotron, The gyrotron, magnet and body power supply have been delivered and successfully installed at the test stand, hosted by the CRPP. The main high voltage power supply delivery is delayed, so one of the power supplies dedicated to 3 of 9 gyrotrons in the TCV EC system is being used as a backup power source (all 3 TCV power sources can be interfaced with the test stand). Cathode conditioning began in November 2007 followed by collector conditioning in December. Parasitic low frequency oscillations have not hindered operation, and the tests have progressed to conditioning out to 0.14 s pulses by March 2008. During this period, the perfomance concerning microwave generation has been characterised and the RF beam profile has been measured at several planes to allow reconstruction of the phase and amplitude profile at the gyrotron window and to provide the necessary information permitting proper alignment of the compact RF loads prior to pulse extension. The power will be measured, according to the pulse length, using either a very-short pulse (<0.01 s) load on loan from FZK, or short-pulse (<0.2 s) or long-pulse (CW), spherical, calorimetric loads developped as part of this program by CNR. This paper presents the preliminary results of these operations.

Goodman, T. P.; Alberti, S.; Droz, E.; Fasel, D.; Hogge, J. P.; Jawla, S.; Porte, L.; Siravo, U.; Tran, M. Q.; Albajar, F.; Bonicelli, T.; Benin, P.; Bethuys, S.; Lievin, C.; Cirant, S.; Dumbrajs, O.; Gantenbein, G.; Illy, S.; Jin, J.; Kern, S.; Piosczyk, B.; Rzesnicki, T.; Thumm, M.

2009-04-01

390

Initial Experimental Results of a Laboratory Mini-Magnetosphere for Astronaut Protection  

NASA Astrophysics Data System (ADS)

Radiation is a major scientific and technological challenge for manned missions to Mars. With an interplanetary flight time of months to years there is a high probability of Solar Energetic Particle events during the flight. Radiation damage to human tissue could result in acute sickness or death of the occupants of an unprotected spacecraft. Thus there is much interest in techniques to mitigate the effects of these events and of the exposure to cosmic rays. The experimental and modelling work presented here concerns one of several innovative "Active Shield" solutions being proposed [1]. The idea of generating an artificial magnetosphere to recreate the protective shield of the Earth's magnetic field for space craft travelling to the Moon or Mars was considered seriously in the 1960's during the Apollo era. With most of the space agencies around the world setting their sights returning to the Moon and then on to Mars, the idea of some sort of active field solution is experiencing a resurgence. Results from the laboratory experiment to determine the effectiveness of a mini-magnetosphere barrier to be able to expel a flowing energetic "solar wind" plasma will be presented. This is compared to a 3D hybrid simulation code that has been successfully compared to other astrophysical situations e.g. AMPTE artificial comet releases [2]. The experiment and modelling comparisons will demonstrate the scalability between the laboratory and astrophysical scale. [1] Adams, J.H. et al., "Revolutionary Concepts of Radiation Shielding for Human Exploration of Space", NASA/TM- 2005-213688, March 2005. [2] Gargate, L.; Bingham, R.; Fonseca, R. A.; Silva, L. O., "dHybrid: A massively parallel code for hybrid simulations of space plasmas", Computer Physics Communications, Volume 176, Issue 6, Pages 419-425, 15 March 2007, doi:10.1016/j.cpc.2006.11.013

Bamford, R. A.; Bingham, R.; Gibson, K.; Thornton, A.; Bradford, J.; Hapgood, M.; Gargate, L.; Silva, L.; Norberg, C.; Todd, T.; Wilson, H.; Stamper, R.

2007-12-01

391

Experimental validation of a distributed parameter piezoelectric bimorph cantilever energy harvester  

NASA Astrophysics Data System (ADS)

Recent rapid advances in low-power portable electronic applications have motivated researchers and industry to explore schemes to embed an endless power supply mechanism within these systems. These self-charging embedded power supply systems convert ambient energy (vibration, solar, wind, etc) into electrical energy and subsequently provide power to these portable applications. Ambient vibration is one of the most promising sources of energy as it is abundantly present in indoor/outdoor systems. This paper discusses briefly the mathematical model of a bimorph piezoelectric cantilever beam with distributed inertia, and its experimental validation. Research on such a component typically included a tip mass, which reduced the influence of the distributed inertia of the beam and restricted effective operation to low frequencies. The present work excludes the tip mass and only the distributed mass of the harvester is considered. Due to the coupled electromechanical nature of piezoelectric materials, the effects of electrical coupling on the mechanical properties of the harvester are investigated, particularly the dependence of the induced additional stiffness and damping on the electrical load. Both the model and the experimental results show that the resonance frequency and the response amplitude of the harvester exhibit considerable shifts due to the electrical coupling. The experimental work uses both magnitude and Nyquist plots of the electromechanical frequency response functions to thoroughly validate the accuracy and applicability of the distributed parameter model at higher frequencies than previously considered.

Rafique, S.; Bonello, P.

2010-09-01

392

Efficiency of hydrogen based storage systems for stand-alone PV applications: Numerical and experimental results  

Microsoft Academic Search

Photovoltaic (PV) technology is playing an important role as clean and long lasting electrical source. Energy storage is a prerequisite for using PV energy in stand-alone applications, in smart grid and for increase system reliability. Observing that today the hydrogen is an emerging solution as energy vector, PV-hydrogen system can be studied. The paper discusses the integration between the PV

D. Iannuzzi; M. Pagano

2009-01-01

393

UVA experimental and high energy physics. Final grant report  

SciTech Connect

The period 1992--1997 was a mixture of frustrations and of accomplishments for the UVa HEP group. The experimental HEP group began this period with the completion of a truncated run of Experiment E771 at Fermilab in 1992. This experiment was designed to measure the cross section for beauty production in 800 GeV/c pN interactions. It succeeded in this goal as well as in obtaining one of the best limits on FCNC in charm decays by setting an upper limit on D{sup 0} {r_arrow} {mu}{sup +}{mu}{sup {minus}}. In addition, they were able to measure {Psi}, {Psi}, {chi}{sub 1},{chi}{sub 2} and upsilon production. Three UVa PhD theses have resulted from this experiment (as well as 12 other PhD's at other institutions). At the same time, the UVa experimental group was vigorously pursuing the goal of studying CP violation in B production. This took the form of a proposal to the SSC for a super fixed target facility, the SFT, which would focus on studies of B mesons. B. Cox was the spokesman of this experiment that had over thirty institutions. This proposal EOI-14 had a good reception by the SSC PAC. A R and D activity to prove the technique of crystal channeling was undertaken to prove the accelerator aspects of this proposal. This activity, known as E853 or CEX at Fermilab, resulted in proof of the crystal channeling technique as viable for the extraction of 20 TeV beam at the SSC. In addition to this activity, the UVa group investigated many other aspects of B physics at the SSC. They were among the leaders of the 1993 Snowmass meeting on B Physics at Hadronic Accelerators. The UVa HEP group worked vigorously on developing the ideas for B physics at the SSC, as evidenced by the many different studies listed in the publication list given, up to the very day the SSC was terminated by an act of Congress.

Cox, B.

1999-10-07

394

Experimental Protocol and Preliminary Results of Air Infiltration Rate Measurements in Tennessee Valley Homes.  

National Technical Information Service (NTIS)

The principal objective of this multipollutant indoor air quality study focuses on measurement of radon and radon progeny. Details of the radon monitoring component and the chemical pollutant monitoring aspects of the study and associated experimental met...

A. R. Hawthorne C. S. Dudney T. G. Matthews K. P. Monar J. L. Quillen

1986-01-01

395

The Results of an Experimental Study to Measure Some of the Parameters of Spasticity.  

National Technical Information Service (NTIS)

An experimental program was conducted using the Myotron to quantitatively measure some of the parameters of spasticity in hemiplegic patients. The elbow joint behavior of four normal subjects and three hemiplegic subjects was measured. The engineering mea...

J. S. Miller

1968-01-01

396

First experimentally determined thermodynamic values of francium: hydration energy, energy of partitioning, and thermodynamic radius.  

PubMed

The Gibbs energy of partitioning of Fr(+) ion between water and nitrobenzene has been determined to be 14.5 ± 0.6 kJ/mol at 25 °C, the first ever Gibbs energy of partitioning for francium in particular and the first ever solution thermodynamic quantity for francium in general. This value enabled the ionic radius and standard Gibbs energy of hydration for Fr(+) to be estimated as 173 pm and -251 kJ/mol, respectively, the former value being significantly smaller than previously thought. A new experimental method was established using a cesium dicarbollide as a cation-exchange agent, overcoming problems inherent to the trace-level concentrations of francium. The methodology opens the door to the study of the partitioning behavior of francium to other water-immiscible solvents and the determination of complexation constants for francium binding by receptor molecules. PMID:23848436

Delmau, Lætitia H; Moine, Jérôme; Mirzadeh, Saed; Moyer, Bruce A

2013-07-31

397

Flame-Spreading over the Surface of a Solid Propellant Part 1: Experimental Results  

Microsoft Academic Search

Flame-spreading over the surface of a flat solid propellant in a turbulent boundary layer has been investigated experimentally. Nitrogen gas was used as a main flow gas, and noncatalyzed and catalyzed double-base propellants were used as specimens. Experimental measurements of the flame-spreading were conducted as a function of the main stream velocity in a small scale wind tunnel under atmospheric

E. ANDOH; M. MIZOMOTO; S. IKAI

1981-01-01

398

Experimental Results for Low-Temperature Silicon Micromachined Micro Heat Pipe Arrays Using Water and Methanol as Working Fluids  

Microsoft Academic Search

An experimental test facility was constructed to test and verify the operation of two parallel arrays of anisotropicalfy micromachined (etched) micro heal pipes (MHPs) on a single crystalline (100) semiconductor silicon wafer, A micro heat pipe is a small-scale device used to transport energy from a heat source to a heat sink in nearly isothermal operation. The individual MHP was

Bassam Badran; Frank M. Gerner; Padmaja Ramadas; Thurman Henderson; Karl W. Baker

1997-01-01

399

Regional Assesssment and Monitoring of Teh Carbon Balance Within Europe (recab): Experimental Strategy and Mesoscale Modeling Preliminary Results  

NASA Astrophysics Data System (ADS)

The aim of RECAB project (EU project EVK2-CT-1999-00034) is to quantify the contribution of fossil fuel and biospheric sources and sinks of CO2 in Europe to the atmospheric concentration at the regional scale by using a generic coupled bio- sphere atmosphere modelling and experimental approach. To achieve this, a coupled mesoscale-land surface model incorporating the biosphere is being developed; a flux aircraft for low flying purposes was set up and is being used for the regional flux mea- surements (Sky Arrow 650 TCN version ERA); and a system for collecting flask sam- ples to determine gas concentrations (CH4, CO2 and N2O) and isotope ratios (ä13C and ä18O in CO2) is operative on small aircrafts is also set up. The ERA represents the first attempt in Europe to measure surface mass and energy fluxes using airborne eddy covariance. The ERA uses the Best Aircraft Turbulence Probe (BAT) probe that is being developed by NOAA and Airborne Research Australia (ARA). The BAT in- corporates a pressure sphere housing with a synthesis of differential GPS (DGPS), solid-state sensors, and electronic and aerodynamic technology to allow high fidelity turbulence measurements from any aeroplane. CO2 and water vapour concentrations are measured using a fast response open-path infrared gas analyser (LiCor7500) which is mounted on the aircraft nose. For the flask sampling air probes are taken as twin pairs at different flight levels. During the flights the track is recorded by GPS and meteorological parameters as also the CO2 concentration (LiCor6251) are measured online to employ a CBL-Budget-Method as another approach. Additional air probes are taken with a similar sampling unit at ground level within sites of characteristic land use for gas concentration analyses and isotope ratio determination. Three summer (Valencia, Spain; Hainich, Germany; Norunda, Sweden) and three winter (Valencia; 1 Hainich; Loobos, Netherlands) experimental campaigns were successfully executed. Experimental deployments and preliminary experimental an modelling results show- ing different synoptic weather conditions are available, including CO2 vertical profiles (isotopes and concentration), horizontal flux transects and other relevant parameters. Also measurements from eddy flux towers in the measurement areas. are available, and in addition various ABL probes (RASS, SODAR, tethered balloons). 2

Dolman, H.; de Martino, B.; Gioli, B.; Hutjes, R. W. A.; Lindroth, A.; Miglietta, F.; Millan, M. M.; Sanz, M. J.; Schumacher, M.

400

The National Ignition Facility Status and Plans for Laser Fusion and High Energy Density Experimental Studies  

Microsoft Academic Search

The National Ignition Facility (NIF) currently under construction at the University of California Lawrence Livermore National Laboratory is 192-beam, 1.8 Megajoule, 500 Terawatt, 351 nm laser for inertial confinement fusion and high energy density experimental studies. NIF is being built by the Department of Energy and the National Nuclear Security Agency to provide an experimental test bed for the US

Craig R. Wuest

2001-01-01

401

Numerical and experimental investigation on frosting of energy-recovery ventilator  

NASA Astrophysics Data System (ADS)

Frosting of energy-recovery ventilators results in two major problems: increase of pressure losses and reduction of heat transfer rates. Frost formation of heat and mass exchangers used in these ventilation systems is investigated both experimentally and numerically. A numerical model for the prediction of the thermal behavior of the exchanger is presented. The model is validated with experimental data and is then employed to conduct a parametric study. Results indicate that the absolute humidity is the prevailing parameter for characterizing the frosting phenomenon. A frost-mass-fraction chart is established in terms of the absolute humidity of the warm exhaust stream and of the temperature of the cold supply stream. The effect of time and mass flowrate is also evaluated. The transient three-dimensional model shows that the absolute humidity and the temperature of both air flows vary nonlinearly in the frosted zone.

Bilodeau, Stephane; Mercadier, Yves; Brousseau, Patrick

402

Hazards by shock waves during explosive eruptions: preliminary results of experimental investigations.  

NASA Astrophysics Data System (ADS)

A recent study (Scolamacchia and Shouwenaars, 2009) investigated the nature of microscopic craters on the steel surface of a basketball pole left standing in one of the villages destroyed by the 1982 eruption of El Chichón volcano. The craters were attributed to the impacts of ash particles (70-280 ?m) accelerated by shock waves due to an efficient momentum coupling with a gas phase, such that a sudden expansion of the gas, caused by shock wave propagation, drag the particles up to speeds of 710 to 980 m/s. Several open questions existed on this kind of phenomena. Preliminary tests were performed to investigate the correlation between particle size and the high velocities calculated, based on inner deformation of the steel and crater geometry. We used a shock tube apparatus consisting of a high-pressure (HP) steel autoclave, pressurized with Ar gas, and a low pressure (LP) tank at atmospheric conditions. We used ash and lapilli bulk samples from El Chichón trachyandesites, and lapilli with random irregular shapes obtained by crushing and abrading dacitic blocks from pyroclastic flow deposits of Unzen volcano. The samples were placed inside an autoclave at ambient T and P, located between the HP autoclave and the LP tank. Steel plates (same type of the original impacted material), were fixed to the LP tank walls, 10 cm above the autoclave that contained the samples. Shock waves were generated by the sudden decompression of the Ar gas due to the systematical failure of a diaphragm (which separate the LP from the HP section). Air expansion accelerated the particles from below toward the steel plate. The speed of the particles was measured using a system of 4 copper wires conducting an electric signal. The signals dropped when the particles reached the wires. We used low pressure ranges (3.1 to 9.8 MPa) for all experimental runs, obtaining a range of particles velocities between 40 and 257 m/s. These velocities can be attained by pyroclastic density currents. Higher velocities (205 to 257 m/s) were obtained for smaller grain-sizes, in a range of fine lapilli-medium ash (2.8 to 177 ?m). Lower velocities, 40 m/s to 85 m/s, were attained by medium (8 mm) and fine lapilli (4 mm), respectively. These values seem not directly related to the the material composition. Impacts craters on steel plates were experimentally obtained, but we did not observe a modification of the steel inner structure, as observed in the original impacted pole. These results are in agreement with impacts occurred at low particle velocities, typical for gravity driven currents, as those reached in these experiments. We observed a great reduction in grain-size of samples recovered after all experiments with respect to the original material. Such evidence coud be due not only to the disruption of grains when impacting the metal plate, but also to processes stricly related to shock wave propagation and gas expansion. These preliminary results need to be further investigated.

Scolamacchia, Teresa; Alatorre Ibarguengoïtia, Miguel; Spieler, Oliver; Dingwell, Donald B.

2010-05-01

403

Experimental energy barriers to anions transporting through nanofiltration membranes.  

PubMed

Environmentally relevant contaminants fluoride, chloride, nitrate, and nitrite face Arrhenius energy barriers during transport through nanofiltration (NF) membranes. The energy barriers were quantified using crossflow filtration experiments and were in the range of 7-17 kcal·mol(-1), according to ion type and membrane type (Filmtec NF90 and NF270). Fluoride faced a comparatively high energy barrier for both membranes. This can be explained by the strong hydration energy of fluoride rather than other ion properties such as bare ion radius, fully hydrated radius, Stokes radius, diffusion coefficient, or ion charge. The energy barrier for fluoride decreased with pressure, indicating an impact of directional force on energy barriers. The influence of temperature-induced pore radius variability and viscosity on energy barriers was considered. The novel link between energy barriers and ion properties emphasizes the importance of ion hydration and/or partial dehydration mechanisms in determining transport in NF. PMID:23298263

Richards, Laura A; Richards, Bryce S; Corry, Ben; Schäfer, Andrea I

2013-02-08

404

The influence of taxes and subsidies on energy purchased in an experimental purchasing study.  

PubMed

There is limited research on how taxes and subsidies would influence the energy and nutritional quality of food purchases. Using an experimental analogue purchasing task, we examined the effects of increasing the price of high-calorie-for-nutrient foods or reducing the price of low-calorie-for-nutrient foods by 12.5% and 25% on mothers' purchases of 68 common foods and drinks. Taxing less healthy foods with low nutrient density reduced energy (caloric) intake, while reducing the proportion of fat and increasing the proportion of protein purchased. Subsidizing more healthful foods with high nutrient density increased energy intake, without changing the macronutrient profile of foods purchased. These results favor taxes as a way to reduce caloric intake. PMID:20424078

Epstein, Leonard H; Dearing, Kelly K; Roba, Lora G; Finkelstein, Eric

2010-02-05

405

Experimental validation of impact energy model for the rub-impact assessment in a rotor system  

NASA Astrophysics Data System (ADS)

An experimental setup which can simulate the rotor-to-stator rub in a rotor system is installed. A rub screw is used to simulate the condition of local rub-impact fault. Based on the theory of elastic collision and energy conservation, an Impact Energy Model (IEM) is proposed to evaluate the probability or severity of rub-impact fault. To prove this model, the paper conducts the experiment in two steps i.e. hammer test and rub-impact fault validation. The wave signal, spectrum and axis orbit are used to analyze the severity of the rub-impact fault when it occurs. The analysis result shows that the proposed Impact Energy Model (IEM) is effective in the assessment of rub-impact fault. Furthermore, the proposed IEM can also provide a reference for the design and operation of a rotor system.

Cong, Feiyun; Chen, Jin; Dong, Guangming; Huang, Kun

2011-10-01

406

Experimental observation of energy dependence of saturation thickness of multiply scattered gamma photons  

NASA Astrophysics Data System (ADS)

The gamma photons continue to soften in energy as the number of scatterings increases in the target having finite dimensions both in depth and lateral dimensions. The number of multiply scattered photons increases with an increase in target thickness, and saturates at a particular value of the target thickness known as saturation thickness (depth). The present measurements are carried out to study the energy dependence of saturation thickness of multiply scattered gamma photons from targets of various thicknesses. The scattered photons are detected by a properly shielded NaI(Tl) gamma ray detector placed at 90° to the incident beam. We observe that the saturation thickness increases with increasing incident gamma photon energy. Monte Carlo calculations based upon the package developed by Bauer and Pattison [Compton scattering experiments at the HMI (1981), HMI-B 364, pp. 1 106] support the present experimental results.

Singh, Manpreet; Singh, Gurvinderjit; Singh, Bhajan; Sandhu, B. S.

2008-09-01

407

STAR Results from the RHIC Beam Energy Scan-I  

NASA Astrophysics Data System (ADS)

The Beam Energy Scan (BES) program is being pursued at RHIC to study the QCD phase diagram, and search for the possible QCD phase boundary and possible QCD critical point. The data for Phase-I of the BES program have been collected for Au+Au collisions at center-of-mass energies (s)of7.7,11.5,19.6,27,and39GeV. These collision energies allowed the STAR experiment to cover a wide range of baryon chemical potential ?B(100–400MeV) in the QCD phase diagram. We report on several interesting results from the BES Phase-I covering the high net-baryon density region. These results shed light on particle production mechanism and freeze-out conditions, first-order phase transition and "turn-off" of QGP signatures, and existence of a critical point in the phase diagram. Finally, we give an outlook for the future BES Phase-II program and a possible fixed target program at STAR.

Kumar, Lokesh

2013-05-01

408

Energy and Work, Science (Experimental): 5348.05.  

ERIC Educational Resources Information Center

This unit of instruction introduces the measuring of work, power, and energy; forms of energy; conversion and conservation of energy; and types of machines. It is a course suggested for the terminal science student. No requisites for prior course work are suggested. The booklet lists the state-adopted texts in the list of references. It states the…

Plotts, Paul L.

409

Marine pollution network euromar-mermaid: Results of the experimental operation  

NASA Astrophysics Data System (ADS)

The need for automated systems to monitor chemical and biochemical variables led to the definition of the EUREKA-EUROMAR project MERMAID. It was realized by several international scientific and industrial partners. Important components were automatic nutrient analyzers and remote-controlled samplers for toxic trace substances in addition to a high-performance data management system with bi-directional telemetry units for remote-controlled network operation. These modules were implemented in the MERMAID network consisting of three sea stations, two of them set up in the Elbe estuary, and one in the Elbe-influenced coastal zone. The latter was at the same time part of the BSH-network. The data were transmitted to shore and processed at GKSS and BSH. While in the preceding project phase the marine pollution network was established and tested, the last MERMAID phase covered its experimental operation. For this purpose, different modules were installed at the three stations. They incorporated meteorological, oceanographic, physical and chemical sensors in addition to automatic analyzers for phosphate, nitrite/nitrate and ammonium as well as specialized samplers for heavy metals and organic micropollutants. Variables were determined directly either continuously by in situ sensors or at variable time intervals by remote-controlled in situ analyzers, or they were determined indirectly by samplers allowing phase-separated multiple sampling with remote or event control of the sampling frequency. In this contribution, the results of nutrient and heavy metal concentration time series measured in 1995 and 1996 are presented together with corresponding meteorological and oceanographic variables. The examples indicate that the transfer of nutrients and contaminants in the estuary and in the coastal zone is strongly influenced by different short- and long-term events, i.e. freshwater discharge rates and wind action. Additionally, in summer, chemical and biological processes influence the fate of these substances on their way from the river to the coastal zone to a high degree. The present results and some earlier findings allow the conclusion that the existing monitoring procedures should be supplemented by new measuring methods. This can be accomplished by means of strategically placed fixed stations at which continuous, short-interval measurements of chemically and biologically relevant parameters are carried out. To cut down laboratory costs for trace analyses, the automated sampling should be ‘intelligent’ and event-controlled.

Knauth, H.-D.; Schroeder, F.; Menzel, R.; Gebhart, E.; Marx, S.; Kohnke, D.; Holzkamm, F.; Nies, H.; Theobald, N.

1997-09-01

410

Sodium laser guide star system at Lawrence Livermore National Laboratory: System description and experimental results  

SciTech Connect

The architecture and major system components of the sodium-layer kw guide star system at LLNL will be described, and experimental results reported. The subsystems include the laser system, the beam delivery system including a pulse stretcher and beam pointing control, the beam director, and the telescope with its adaptive-optics package. The laser system is one developed for the Atomic Vapor Laser Isotope Separation (AVLIS) Program. This laser system can be configured in various ways in support of the AVLIS program objectives, and was made available to the guide star program at intermittent times on a non-interference basis. The first light transmitted into the sky was in July of 1992, at a power level of 1. 1 kW. The laser pulse width is about 32 ns, and the pulse repetition rate was 26 kHz for the 1. 1 kW configuration and 13 kHz for a 400 W configuration. The laser linewidth is tailored to match the sodium D{sub 2} absorption line, and the laser system has active control of beam pointing and wavefront quality. Because of the short pulse length the sodium transition is saturated and the laser power is not efficiently utilized. For this reason a pulse stretcher was developed, and the results of this effort will be reported. The beam is delivered via an evacuated pipe from the laser building to the guide star site, a distance of about 100 meters, and then launched vertically. A beam director provides the means to track the sky in the full AO system, but was not used in the experiments reported here. The return signal is collected by a 1/2 meter telescope with the AO package. This telescope is located 5 meters from the km launch tube. Smaller packages for photometry, wavefront measurement, and spot image and motion analysis have been used. Although the unavailability of the AVLIS laser precluded a full AO system demonstration, data supporting feasibility and providing input to the system design for a Lick Observatory AO system was obtained.

Avicola, K.; Brase, J.; Morris, J. [and others

1994-03-02

411

Chlorine Stable Isotope Composition of Altered Oceanic Crust: Empirical and Experimental Results  

NASA Astrophysics Data System (ADS)

Chlorine is an excellent geochemical tracer of fluid-rock interactions because it strongly partitions into the aqueous fluid phase. Chlorine can be used to study the migration of fluids in the crustal environment, volatiles in subduction zones, and the interaction between oceanic lithosphere and seawater-derived hydrothermal fluids. Cl is only a useful tracer, however, if 1) the ?37Cl values of potential chlorine reservoirs and 2) the relevant equilibrium chlorine isotope fractionation factors are both well constrained. Poor constraints on both 1 and 2 for altered oceanic crust (AOC) severely limit our understanding of the global Cl cycle. Here we present ?37Cl values of AOC sampled by the Ocean Drilling Program (ODP). Samples from the Southwest Indian Ridge (ODP Hole 735B) have ?37Cl values ranging from -0.2 to +0.2‰ (error < ± 0.3‰) vs. SMOC (Standard Mean Ocean Chloride, defined as 0‰). Samples from the Western Pacific (ODP Hole 801C) have ?37Cl values ranging from -0.4 to +0.8‰. ODP Site 735 samples a 11 Ma lower section of slow spreading (0.6-1.0 cm/yr) oceanic crust. In contrast, ODP Site 801 is located in ~170 Ma fast-spreading crust (16 cm/yr). Despite those differences in age and tectonic setting, the ?37Cl values of AOC are remarkably similar, implying similar sources and mechanisms of hydration. The only previously reported AOC ?37Cl values are from the Costa Rica Rift (ODP Hole 504B). Site 504 was drilled into 5.9 Ma crust from an intermediate spreading center (~3 cm/yr). ?37Cl values range from -1.6 to -0.9‰ (Bonifacie et al., 2007). Our study expands the range of ?37Cl values reported for AOC, and can be used to reevaluate mass balance calculations improving our understanding of subduction recycling. Experimental and theoretical constraints on chlorine isotope fractionation in inorganic systems are limited to only a handful of studies. Theoretical calculations estimate that at 25°C substances in which Cl bonds with 2+ cations will be ~ +2-3‰ heavier than those in which Cl bonds with 1+ cations (Schauble et al., 2003). These calculations have led to the hypothesis that silicates should have higher 37Cl/35Cl ratios than co-existing brines at room temperature (Schauble et al., 2003). Preliminary Cl isotope fractionation experiments between pargasitic amphibole and either seawater or brine (25 wt% NaCl solution) were run in cold-seal pressure vessels at 600°C and 500 bars. Preliminary results suggest that ?37Clpargasite-Cl(aq) is within analytical error of the theoretically predicted fractionation factor, as well as measured ?37Cl values of AOC samples. Further work is planned to investigate the role of fluid-rock ratio and amphibole composition. Additional experimental data may allow us to infer the fluid-rock ratio and temperature during hydration of natural samples and to unravel the fluid histories recorded in the alteration minerals.

Barnes, J.; Gardner, J. E.

2010-12-01

412

Experimental Estimation for Beat-Wave Current Generation in an Unmagnetized Plasma and Preliminary Results  

NASA Astrophysics Data System (ADS)

Beat-wave current generation experiment in a high density compact torus (CT) is being conducted on CTIX using CO2 lasers. Tunability of the CO2 lasers provides many options for the wave-particle interaction experiment at a variety of plasma densities with plasma frequency in THz range. For example strong lines such as 9R(12) and 9R(30) could be chosen for an easily obtainable density of 1.28x10^15cm-3. After restoration, two Lumonics CO2 lasers are expected to produce approximately 100MW output power in a 50ns pulse. The amount of energy transfer from laser to plasma is determined by the laser power intensity, and by the CT density scale length [1]. The desired power density can be achieved by designing a suitable optical focusing system. In addition, the CT density can be matched to the beat-wave frequency by appropriately selecting the plasma operating conditions and timing. Extensive testing of the Marx banks and pre-ionization boards was done under a variety of operating conditions. Other preliminary results and plans for the wave-particle interaction experiment will also be reported. [1] A. N. Kaufman, B. I. Cohen, PRL, 30 1306 (1973)

Liu, Fei; Horton, Robert; Hwang, David; Zhu, Ben; Evans, Russell

2009-11-01

413

The 110 GHz ECH installation on DII-D: Status and initial experimental results  

SciTech Connect

Two 110 GHz gyrotrons with nominal output power of 1 MW each have been installed on the DIII-D tokamak. The gyrotrons, produced by Gycom and Communications and Power Industries, are connected to the tokamak by windowless evacuated transmission lines using circular corrugated waveguide carrying the HE{sub 11} mode. Initial experiments with the Gycom gyrotron showed good central heating efficiency at the second harmonic resonance with record central electron temperatures for DIII-D in excess of 10 keV achieved. The beam spot in the DIII-D vacuum vessel was well focused, with a diameter of approximately 8 cm, and it could be steered poloidally by a remotely adjustable mirror. The injection was at 19 deg off-perpendicular for current drive and the beams could be modulated for studies of energy transport and power deposition. The system will be described and the initial physics results will be presented. A third gyrotron, also at 110 GHz, will be installed later this year. Progress with this CPI tube will be discussed and future plans for the ECH installation and physics experiments using it will be presented.

Lohr, J.; Callis, R.W.; O`Neill, R.C. [Univ. of Texas, Austin, TX (United States)] [and others

1997-05-01

414

Beta decay and the origin of biological chirality: New experimental results  

NASA Astrophysics Data System (ADS)

The proposed connection between the parity-violating handedness of beta particles in radioactive decay and the sign (L) of biological chirality (the Vester-Ulbricht [V-U] hypothesis) is being investigated by measuring the theoretically predicted asymmetry in the formation of triplet positronium in amino acid enantiomers by low energy positrons under reversal of the helicity of the positrons. We find the asymmetry in leucine to be (0.8±1.0)×10-4, i.e. consistent with the theoretical, prediction of 10-6 to 10-7. The apparatus is now sensitive enough to test the predicted asymmetry in optically active molecules which have heavy atoms at their chiral centers. The connection between these results and asymmetry in radiolysis by beta-decay electrons is made, and the implications of our limits for the V-U hypothesis discussed. Although the above limits are 106 times lower than direct measurements of radiolysis, they are still not small enough to allow us to rule out the V-U hypothesis.

van House, J.; Rich, A.; Zitzewitz, P. W.

1984-12-01

415

Nonsingular adsorption/desorption of chlorpyrifos in soils and sediments: experimental results and modeling.  

PubMed

At environmentally relevant concentrations in soils and sediments, chlorpyrifos, a hydrophobic organic insecticide, showed strong adsorption that correlated significantly with organic matter content. Chlorpyrifos desorption followed a nonsingular falling desorption isotherm that was estimated using a memory-dependent mathematical model. Desorption of chlorpyrifos was biphasic in nature, with a labile and nonlabile component. The labile component comprised 18-28% of the original solid-phase concentration, and the residue was predicted to slowly partition to the aqueous phase, implying long-term desorption from contaminated soils or sediments. The newly proposed mechanism to explain sorption/desorption hysteresis and biphasic desorption is the unfavorable thermodynamic energy landscape arising from limitation of diffusivity of water molecules through the strongly hydrophobic domain of soils and sediments. Modeling results suggest that contaminated soils and sediments could be secondary long-term sources of pollution. Long-term desorption may explain the detection of chlorpyrifos and other hydrophobic organic compounds in aquatic systems far from application sites, an observation that contradicts conventional transport predictions. PMID:22087505

Gebremariam, Seyoum Yami; Beutel, Marc W; Flury, Markus; Harsh, James B; Yonge, David R

2011-12-21

416

Experimental determination of the solubility of iridium in silicate melts: Preliminary results  

NASA Astrophysics Data System (ADS)

Little is known of the geochemical behavior of iridium. Normally this element is taken to be chalcophile and/or siderophile so that during planetary differentiation processes, e.g., core formation, iridium is extracted from silicate phases into metallic phases. Experimental determination of the metal/silicate partition coefficient of iridium is difficult simply because it is so large. Also there are no data on the solubility behavior of iridium in silicate melts. With information on the solubility of iridium in silicate melts it is possible, in combination with experimental data for Fe-Ir alloys, to calculate the partition coefficient between a metallic phase and a silicate melt.

Borisov, Alexander; Dingwell, Donald B.; Oneill, Hugh St. C.; Palme, Herbert

417

Design Considerations and Experimental Results of a 60 W Compressed-Air-to-Electric-Power System  

Microsoft Academic Search

In many process applications, where a pressure reduction is required the energy ends up being dissipated as heat. Examples are throttling valves of gas pipelines and automotive engines or turbo expanders as used in cryogenic plants. With a new pressure reduction system that produces electricity while expanding the gas, this lost energy can be recovered. To achieve a high power

D. Krahenbiihl; C. Zwyssig; H. Horler; J. W. Kolar

2008-01-01

418

Experimental Results of Olive Pits Gasification in a Fixed Bed Downdraft Gasifier System  

Microsoft Academic Search

Environmental legislation and interest in using newly utilized renewable biomass energy sources in small-scale downdraft biomass gasifiers have stimulated this research work. Biomass gasification for the production of green and clean energy generation in the form of electricity and\\/or heat is a viable alternative to fossil fuels and a clean technology, which can reduce greenhouse gas emissions and facilitate closure

Murat Dogru

2012-01-01

419

The Beam Energy Scan at RHIC: Recent Results from STAR  

NASA Astrophysics Data System (ADS)

The first phase of the beam energy scan (BES) program at RHIC was successfully completed in the years 2010 and 2011. The main goals are the search for the QCD critical point and to find signatures for a phase transition between the hadron gas and the QGP phase. For this purpose several observables like higher moments of net-proton distributions, RCP of charged hadrons or the elliptic flow v2 are studied. Further new observations and results like the centrality dependence of chemical freeze-out parameters (Tch and ?B) or di-electron spectra in comparison with model calculations are discussed.

Schmah, Alexander; STAR Collaboration

2013-03-01

420

Short Term Test Results: Multifamily Home Energy Efficiency Retrofit.  

National Technical Information Service (NTIS)

Multifamily deep energy retrofits (DERs) on relatively common building types are valuable research efforts for the U.S. Department of Energy's Building America Program. Such buildings represent great potential for energy savings, while providing valuable ...

J. Lyons

2013-01-01

421

Multiple Measures of Juvenile Drug Court Effectiveness: Results of a Quasi-Experimental Design  

Microsoft Academic Search

Prior studies of juvenile drug courts have been constrained by small samples, inadequate comparison groups, or limited outcome measures. The authors report on a 3-year evaluation that examines the impact of juvenile drug court participation on recidivism and drug use. A quasi-experimental design is used to compare juveniles assigned to drug court with those assigned to standard probation in Maricopa

Nancy Rodriguez; Vincent J. Webb

2004-01-01

422

Perfect versus imperfect observability---An experimental test of Bagwell's result  

Microsoft Academic Search

In a seminal paper Bagwell (1995) claims that the first mover advantage, i.e. the strategic benefit of committing oneself to an action before others can do, vanishes completely if this action is only imperfectly observed by second movers. In our paper we report on an experimental test of this prediction. We implement three versions of a game similar to an

Steffen Huck; Wieland Mueller

1998-01-01

423

Single-Slit Fresnel Diffraction Patterns: Comparison of Experimental and Theoretical Results.  

National Technical Information Service (NTIS)

Experimental work at the University of Utah has produced high-resolution optical diffraction patterns by slit apertures, 20 m from source and 30 m from photomultiplier receiver slit. The slit widths varied in 26 values from 0.5 to 32 mm with 4358- and 546...

F. S. Harris M. S. Tavenner R. L. Mitchell

1968-01-01

424

Sampling depth of soil moisture content by radiometric measurement at 21 cm wavelength: some experimental results  

Microsoft Academic Search

The thickness of soil layer, through which moisture can be directly estimated by means of a microwave radiometer, has been investigated experimentally on a test area in Central Italy by means of airborne sensors. Aircraft remote sensing data, collected on agricultural bare and vegetated fields during the growth stage of vegetation (May-July 1988), have shown that L band microwave emission

P. Pampaloni; S. Paloscia; L. Chiarantini; P. Coppo; S. Gagliani; G. Luzi

1990-01-01

425

Experimental results of an artificial reef programme on the Brazilian coast north of Rio de Janeiro  

Microsoft Academic Search

An experimental evaluation of artificial reefs was carried out on the coast north of Rio de Janeiro, a low-relief bottom area. The reef complex (1500 m 2 ) consisted of two sets (concrete and tire), each comprising 16 modules. Trammel nets were used in monthly samplings of the reef site and a control area. During 2 years of monitoring, 51

Ilana R. Zalmon; Ronaldo Novelli; Marcelo P. Gomes; Vicente V. Faria

2002-01-01

426

LBE–water interaction in sub-critical reactors: First experimental and modelling results  

Microsoft Academic Search

This paper concerns the study of the phenomena involved in the interaction between LBE and pressurised water which could occur in some hypothetical accidents in accelerator driven system type reactors. The LIFUS 5 facility was designed and built at ENEA-Brasimone to reproduce this kind of interaction in a wide range of conditions. The first test of the experimental program was

A. Ciampichetti; P. Agostini; G. Benamati; G. Bandini; D. Pellini; N. Forgione; F. Oriolo; W. Ambrosini

2008-01-01

427

Experimental results for passive sonar arrays with eigenvector-based adaptive beamformers  

Microsoft Academic Search

In this paper, we compare the performance of several eigenvector-based adaptive beamforming (ABF) algorithms on experimental data collected with a passive sonar array. The first eigenvector-based ABF algorithm considered is dominant mode rejection (DMR) with a fixed, bearing independent diagonal loading level. Then, we look at two robust forms of DMR, DMR with a white noise gain constraint and DMR

Stephen M. Kogon

2002-01-01

428

Cooperative relaying in car-to-car communications: Initial results from an experimental study  

Microsoft Academic Search

This paper reports on an experimental study about some benefits of cooperative relays in mobile wireless communications. A basic technique for cooperative relaying is implemented in the programmable hardware platform WARP. Using this implementation, measurements are made for mobile car-to-car communications in a suburban environment. Each of three cars is equipped with a transceiver and serves as sender, relay, or

Gunther Brandner; Udo Schilcher; Christian Bettstetter

2010-01-01

429

The effects of integrative reminiscence on meaning in life: Results of a quasi- experimental study  

Microsoft Academic Search

Objectives: Finding meaning in life is often cited as an important outcome of reminiscence, but this theoretical claim has not been empirically tested until now. A new intervention combining integrative reminiscence and elements of narrative therapy was developed and the effects on meaning in life were studied.Methods: A total of 106 older adults with depressive symptomatology participated in a quasi-experimental

E. T. Bohlmeijer; G. J. Westerhof; M. Emmerik-de Jong

2008-01-01