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1

Energy-resolved computed tomography: first experimental results  

NASA Astrophysics Data System (ADS)

First experimental results with energy-resolved computed tomography (CT) are reported. The contrast-to-noise ratio (CNR) in CT has been improved with x-ray energy weighting for the first time. Further, x-ray energy weighting improved the CNR in material decomposition CT when applied to CT projections prior to dual-energy subtraction. The existing CT systems use an energy (charge) integrating x-ray detector that provides a signal proportional to the energy of the x-ray photon. Thus, the x-ray photons with lower energies are scored less than those with higher energies. This underestimates contribution of lower energy photons that would provide higher contrast. The highest CNR can be achieved if the x-ray photons are scored by a factor that would increase as the x-ray energy decreases. This could be performed by detecting each x-ray photon separately and measuring its energy. The energy selective CT data could then be saved, and any weighting factor could be applied digitally to a detected x-ray photon. The CT system includes a photon counting detector with linear arrays of pixels made from cadmium zinc telluride (CZT) semiconductor. A cylindrical phantom with 10.2 cm diameter made from tissue-equivalent material was used for CT imaging. The phantom included contrast elements representing calcifications, iodine, adipose and glandular tissue. The x-ray tube voltage was 120 kVp. The energy selective CT data were acquired, and used to generate energy-weighted and material-selective CT images. The energy-weighted and material decomposition CT images were generated using a single CT scan at a fixed x-ray tube voltage. For material decomposition the x-ray spectrum was digitally spilt into low- and high-energy parts and dual-energy subtraction was applied. The x-ray energy weighting resulted in CNR improvement of calcifications and iodine by a factor of 1.40 and 1.63, respectively, as compared to conventional charge integrating CT. The x-ray energy weighting was also applied to low- and high-energy CT projections used for material decomposition. This improved the CNR in images of decomposed calcification and iodine by a factor of 1.57 and 1.46, respectively, as compared to conventional charge integrating CT. Some limitations were observed due to hole trapping in CZT and charge sharing between the detector pixels. First experimental results demonstrate that energy-resolved CT is coming close to its practical applications. Although hole trapping and charge sharing in CZT deteriorates x-ray spectrum and limits CNR improvement with energy weighting and detector count rate, this problem has a feasible solution, which is discussed in this paper and is a matter of ongoing research.

Shikhaliev, Polad M.

2008-10-01

2

The Philips energy-experimentation house - Results and experience  

Microsoft Academic Search

A description is presented of intermediate results obtained in a project reported by Bruno et al. (1976). The project involves investigations related to the utilization of solar energy and the efficient use of energy in buildings. Approaches for the reduction of the energy consumption in buildings are discussed, taking into account the reduction of heat losses, a utilization of waste

R. Bruno; W. Hermann; H. Hoerster; R. Kersten; K. Klinkenberg; F. Mahdjuri

1977-01-01

3

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

4

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

5

Experimental Results From the Thermal Energy Storage-1 (TES-1) Flight Experiment  

NASA Technical Reports Server (NTRS)

The Thermal Energy Storage (TES) experiments are designed to provide data to help researchers understand the long-duration microgravity behavior of thermal energy storage fluoride salts that undergo repeated melting and freezing. Such data, which have never been obtained before, have direct application to space-based solar dynamic power systems. These power systems will store solar energy in a thermal energy salt, such as lithium fluoride (LiF) or a eutectic of lithium fluoride/calcium difluoride (LiF-CaF2) (which melts at a lower temperature). The energy will be stored as the latent heat of fusion when the salt is melted by absorbing solar thermal energy. The stored energy will then be extracted during the shade portion of the orbit, enabling the solar dynamic power system to provide constant electrical power over the entire orbit. Analytical computer codes have been developed to predict the performance of a spacebased solar dynamic power system. However, the analytical predictions must be verified experimentally before the analytical results can be used for future space power design applications. Four TES flight experiments will be used to obtain the needed experimental data. This article focuses on the flight results from the first experiment, TES-1, in comparison to the predicted results from the Thermal Energy Storage Simulation (TESSIM) analytical computer code.

Jacqmin, David

1995-01-01

6

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

7

EXPERIMENTAL PLASMAJET THRUSTOR RESULTS  

Microsoft Academic Search

Experimental and analytical development work on thermal arc jet ; propulsion devices for operation in the general area of 800 to 1200-sec specific ; impulse is described. The major accomplishment is the development of the hotwall ; thrustor design to the point where theoretical frozen flow efficiencies were ; equaled or slightly exceeded during several tests. Repeated experimental ; measurements

Masser

1963-01-01

8

Experimental results from wave tank trials of a multi-axis wave energy converter  

NASA Astrophysics Data System (ADS)

A 1/64th scale prototype of multi-axis wave energy converter (WEC) has been tested in the wave tank and the overall concept has been verified. It is shown that when multiple directions of motion are involved, the multi-axis WEC proves to be able to supply more power generation than a single axis one. Results demonstrated that the optimal resonant frequency for maximum power output under different damping values does not vary with wave climate. It is also shown that large overload capability of the system is critical, and indicated that, electric power system is essential to reduce power fluctuations.

Zhang, Dahai; Aggidis, George; Wang, Yifei; Mccabe, Andy; Li, Wei

2013-09-01

9

Validation and verification of MCNP6 against intermediate and high-energy experimental data and results by other codes  

Microsoft Academic Search

MCNP6, the latest and most advanced LANL transport code representing a recent merger of MCNP5 and MCNPX, has been Validated and Verified (V&V) against a variety of intermediate and high-energy experimental data and against results by different versions of MCNPX and other codes. In the present work, we V&V MCNP6 using mainly the latest modifications of the Cascade-Exciton Model (CEM)

S. G. Mashnik

2011-01-01

10

Validation and verification of MCNP6 against intermediate and high-energy experimental data and results by other codes  

Microsoft Academic Search

MCNP6, the latest and most advanced LANL transport code representing a recent merger of MCNP5 and MCNPX, has been Validated\\u000a and Verified (V&V) against a variety of intermediate and high-energy experimental data and against results by different versions\\u000a of MCNPX and other codes. In the present work, we V&V MCNP6 using mainly the latest modifications of the Cascade-Exciton Model\\u000a (CEM)

S. G. Mashnik

2011-01-01

11

Validation and verification of MCNP6 against intermediate and high-energy experimental data and results by other codes  

Microsoft Academic Search

MCNP6, the latest and most advanced LANL transport code representing a recent merger of MCNP5 and MCNPX, has been Validated and Verified (V and V) against a variety of intermediate and high-energy experimental data and against results by different versions of MCNPX and other codes. In the present work, we V andV MCNP6 using mainly the latest modifications of the

Stepan G. Mashnik; Stepan G

2010-01-01

12

Validation and verification of MCNP6 against intermediate and high-energy experimental data and results by other codes  

NASA Astrophysics Data System (ADS)

MCNP6, the latest and most advanced LANL transport code representing a recent merger of MCNP5 and MCNPX, has been Validated and Verified (V&V) against a variety of intermediate and high-energy experimental data and against results by different versions of MCNPX and other codes. In the present work, we V&V MCNP6 using mainly the latest modifications of the Cascade-Exciton Model (CEM) and of the Los Alamos version of the Quark-Gluon String Model (LAQGSM) event generators CEM03.03 and LAQGSM03.03. We found that MCNP6 describes reasonably well various reactions induced by particles and nuclei at incident energies from 18MeV to about 1TeV per nucleon measured on thin and thick targets and agrees very well with similar results obtained with MCNPX and calculations by CEM03.03, LAQGSM03.03 (03.01), INCL4 + ABLA, and Bertini INC + Dresner evaporation, EPAX, ABRABLA, HIPSE, and AMD, used as stand-alone codes. Most of several computational bugs and more serious physics problems observed in MCNP6/X during our V&V have been fixed; we continue our work to solve all the known problems before MCNP6 is distributed to the public.

Mashnik, S. G.

2011-05-01

13

Majorana Thermosyphon Prototype Experimental Results  

SciTech Connect

Objective The Majorana demonstrator will operate at liquid Nitrogen temperatures to ensure optimal spectrometric performance of its High Purity Germanium (HPGe) detector modules. In order to transfer the heat load of the detector module, the Majorana demonstrator requires a cooling system that will maintain a stable liquid nitrogen temperature. This cooling system is required to transport the heat from the detector chamber outside the shield. One approach is to use the two phase liquid-gas equilibrium to ensure constant temperature. This cooling technique is used in a thermosyphon. The thermosyphon can be designed so the vaporization/condensing process transfers heat through the shield while maintaining a stable operating temperature. A prototype of such system has been built at PNNL. This document presents the experimental results of the prototype and evaluates the heat transfer performance of the system. The cool down time, temperature gradient in the thermosyphon, and heat transfer analysis are studied in this document with different heat load applied to the prototype.

Fast, James E.; Reid, Douglas J.; Aguayo Navarrete, Estanislao

2010-12-17

14

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

15

EXPERIMENTAL PROCEDURE & RESULTS PROPOSED METHOD  

E-print Network

ISS-0413012 and also The Experiments were performed with a Sony Camera interfaced with MATLAB curvilniear distortions. Non-uniform pixel distribution. Advantages Curved Lenses & Mirrors produce very wide of the captured image. Imaging with Curved Mirror Theoretical Model Prototype Model Experimental Setup FUTURE WORK

Kurzweg, Timothy P.

16

Capacitive mixing for the extraction of energy from salinity differences: survey of experimental results and electrochemical models.  

PubMed

The "capacitive mixing" (CAPMIX) technique is an emerging technology aimed at the extraction of energy from salinity differences, e.g. between sea and river waters. CAPMIX benefits from the voltage rise that takes place between two electrodes dipped in a saline solution when its salt concentration is changed. Several kinds of electrodes have been proposed so far: activated carbon materials (Brogioli, 2009), membrane-based ion-selective electrodes (Sales et al., 2010), and battery electrodes (Biesheuvel and van der Wal, 2010). The power production mainly depends on two properties of each single electrode: the amplitude of the potential rise upon salinity change, and the potential in the high-salinity solution. The various electrode materials that have been used returned different values of the two parameters, and hence to different power productions. In this paper, we apply electrokinetic and electrochemical models to qualitatively explain the experimentally observed behaviors of various materials under different experimental conditions. The analysis allows to devise techniques for tailoring new materials, particularly suited for the CAPMIX technique. PMID:23871601

Brogioli, D; Ziano, R; Rica, R A; Salerno, D; Mantegazza, F

2013-10-01

17

Experimental electrochemical capacitor test results  

SciTech Connect

Various electrochemical capacitors (ultracapacitors) are being developed for hybrid vehicles as candidate power assist devices for the Partnership for a New Generation of Vehicles (PNGV) fast-response engine. The envisioned primary functions of the ultracapacitor are to level the dynamic power loads on the primary propulsion device and recover available energy from regenerative breaking during off-peak power periods. This paper will present test data from selected US Department of Energy (DOE) supported ultracapacitor projects designed to meet the fast response engine requirements. This paper will address the temperature dependence of test data obtained from a set of three devices provided from Maxwell Energy Products, Inc. These devices are rated at 2,300 F at 2.3 V. Constant-current, constant-power, and self-discharge testing as a function of temperature have been conducted. From these tests were determined the capacitance, equivalent series resistance, specific energy and power, and the self-discharge energy loss factor as a function of the device operating temperature.

Wright, R.B.; Murphy, T.C.; Rogers, S.A.; Sutula, R.A.

1998-07-01

18

Thermal Energy Measurement with Tangential Paddlewheel Flow Meters: Summary of Experimental Results and in-situ Diagnostics  

E-print Network

a totalized signal for input into a data acquisition system. In this paper a summary of experimental results from calibration efforts in the Texas LoanSTAR program are presented, including the premature drop-out of magnetic-type tangential..., or in metering text books (Miller 1989). The signal drop-out problem for magnetic-type flow meters is not a new problem and has been reported in numerous journals dating as far back as 36 years ago5 (Hochreiter 1958). However, there seems to be an unwillingness...

Haberl, J. S.; Watt, J. B.

1994-01-01

19

CSCM: Experimental and Simulation Results  

E-print Network

The Copper-Stabilizer Continuity Measurement (CSCM) was devised to obtain a direct and complete qualification of the continuity in the 13 kA bypass circuits of the LHC, especially in the copper-stabilizer of the busbar joints and the bolted connections in the diodeleads, as well as in lyra connections. The circuit under test is brought to about 20 K, a voltage is applied to open the diodes by-passing the magnets, and the low-inductance circuit is powered according to a pre-defined series of current profiles. The profiles are designed to successively increase the thermal load on the busbar joints up to a level that corresponds to worst-case operating conditions at nominal energy. In this way, the circuit is tested for thermal runaways in the joints - the very process that could prove catastrophic if it occurred under nominal conditions with the full stored energy of the circuit. A type test of the CSCM was successfully carried out in April 2013 on one main dipole and one main quadrupole circuit of the LHC. Thi...

Rowan, S; Brodzinski, K; Charifoulline, Z; Denz, R; Romera, I; Roger, V; Siemko, A; Schmidt, R; Steckert, J; Thiesen, H; Verweij, A; Willering, G; Wollmann, D; Zerlauth, M; Pfeffer, H

2014-01-01

20

An Overview of STAR Experimental Results  

E-print Network

With large acceptance and excellent particle identification, STAR is one of the best mid-rapidity collider experiments for studying high-energy nuclear collisions. The STAR experiment provides full information on initial conditions, properties of the hot and dense medium as well as the properties at freeze-out. In Au+Au collisions at $\\sqrt{s_{NN}} = 200$ GeV, STAR's focus is on the nature of the sQGP produced at RHIC. In order to explore the properties of the QCD phase diagram, since 2010, the experiment has collected sizable data sets of Au+Au collisions at the lower collision energy region where the net-baryon density is large. At the 2014 Quark Matter Conference, the STAR experiment made 16 presentations that cover physics topics including {\\it collective dynamics}, {\\it electromagnetic probes}, {\\it heavy flavor}, {\\it initial state physics}, {\\it jets}, {\\it QCD phase diagram}, {\\it thermodynamics and hadron chemistry}, and {\\it future experimental facilities, upgrades, and instrumentation} [1-16]. In this overview we will highlight a few results from the STAR experiment, especially those from the recent measurements of the RHIC beam energy scan program. At the end, instead of a summary, we will discuss STAR's near future physics programs at RHIC.

N. Xu

2014-08-15

21

EXPERIMENTAL RESULTS ON CROSSBREEDING INVOLVING BEEF  

E-print Network

EXPERIMENTAL RESULTS ON CROSSBREEDING INVOLVING BEEF (PIEDMONT AND ROMAGNA) AND DAIRY CATTLE carried out in order to evaluate the ability for beef production of(Dou- ble-muscled » Piedmont x Friesian, although female crosses appear to possess a good ability for beef production, a three-breed crossing pro

Paris-Sud XI, Université de

22

Synthesis of H2 in dirty ice mantles by fast ion energy loss: New experimental results increase the relevance of this mechanism  

NASA Technical Reports Server (NTRS)

Recent experimental results support the importance of H2 production in molecular clouds by cosmic ray bombardment of the mantles of grains. The formation of molecules different from those originally present in the irradiated layer can be explained by the production of molecular fragments induced by the release of energy if the impinging fast particle. One way of considering the process is in terms of a transiently hot cylinder, initially about 50 A in diameter, that exists around the track of an individual fast ion. Since ice has a relatively low thermal conductivity, energy lost by the ion in the ice layers remains confined around the track for time long enough to be thermalized. The hot cylinder increases in diameter and decreases in temperature on a time scale of 10(exp -11) to 10(exp -10) sec. Molecular fragments that are formed in this high temperature region acquire enough mobility to recombine with different partners, forming new molecules. A Monte Carlo simulation of the interaction between cosmic rays and grain mantles, at various depths in the core of a spherical molecular cloud, was performed. The simulation was continued until 40,000 ions had hit each grain of the type and size chosen. During the performed experiments thin icy films made of H2O and CD4 mixed in the gas phase and deposited on a cold finger at 9 K were irradiated with 1.5 MeV helium beams. Among synthesized molecules were found H2, HD, and D2.

Pirranello, Valero; Brown, W. L.; Lanzerotti, L. J.; Averna, D. A.

1989-01-01

23

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

24

5. EXPERIMENTAL RESULTS The experimental results were obtained with a strat  

E-print Network

(1990),''Automatic Sensor and Light Positioning for Machine Vision,'' In: Proc. of the 10th Int. Conf5. EXPERIMENTAL RESULTS The experimental results were obtained with a strat­ egy using motion about the three camera axes for visual tracking, motion along the three axes for singu­ larity/joint limit

25

Theoretical analysis and experimental results of a 1 kW chem ammonia synthesis reactor for a solar thermochemical energy storage system  

Microsoft Academic Search

A closed-loop solar thermochemical energy storage and transport system using the dissociation and synthesis reactions of ammonia has been investigated at the Australian National University (ANU). Work relating to the optimisation of the heat recovery part of the system is reported. Experimental investigation has shown a 1-kWchem laboratory-scale ammonia synthesis reactor to operate in a stable and repeatable manner. A

H. Kreetz; K. Lovegrove

1999-01-01

26

Experimental results on advanced rotary desiccant dehumidifiers  

SciTech Connect

The Solar Energy Research Institute (SERI) has developed the Cyclic Test Facility (CTF) to develop and validate analytical methods for evaluating and predicting the performance of advanced rotary dehumidifiers. This paper describes the CTF, the dehumidifiers tested at the CTF, and the analytical methods used. The results reported provide an engineering data base and a design tool for evaluating rotary dehumidifiers for desiccant cooling applications.

Bharathan, D.; Parsons, J.; Maclaine-cross, I.

1986-08-01

27

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 centraldensity 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 operatio n 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 plasma current of 1.1 MA

M. Ono; M. Bell; R. E. Bell; T. Bigelow; M. Bitter; et al

2000-11-16

28

Preliminary experimental results from a MARS Micro-CT system.  

PubMed

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 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 among the energy ranges. PMID:22635175

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

2012-01-01

29

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...

30

Energy efficient residence: Research results  

Microsoft Academic Search

The design, construction, and monitoring of an energy efficient residence and a conventional home are compared. The two homes are described in considerable detail, the results of the energy and other measurements are summarized and many of the energy conservation techniques used are evaluated. Two lists of energy saving design tips for homes in both colder and warmer climates are

R. J. Johnson; O. G. Lee

1980-01-01

31

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

32

Adaptive structures - Test hardware and experimental results  

NASA Technical Reports Server (NTRS)

The facilities and procedures used at JPL to test adaptive structures such as the large deployable reflector (LDR) are described and preliminary results are reported. The applications of adaptive structures in future NASA missions are outlined, and the techniques which are employed to modify damping, stiffness, and isolation characteristics, as well as geometric changes, are listed. The development of adaptive structures is shown to be effective as a result of new actuators and sensors, and examples are listed for categories such as fiber optics, shape-memory materials, piezoelectrics, and electrorheological fluids. Some ground test results are described for laboratory truss structures and truss test beds, which are shown to be efficient and easy to assemble in space. Adaptive structures are shown to be important for precision space structures such as the LDR, and can alleviate ground test requirements.

Wada, Ben K.; Fanson, James L.; Chen, Gun-Shing; Kuo, Chin-Po

1990-01-01

33

Experimental Results of Concurrent Learning Adaptive Controllers  

E-print Network

that a concurrent learning adaptive controller improves the trajectory tracking performance of a quadrotor with baseline linear controller directly imported from another quadrotors whose inertial characteristics on indoor quadrotor platforms operated in MIT's RAVEN environ- ment. These results indicate the feasibility

How, Jonathan P.

34

Experimental Results of the Coaxial Multipactor Experiment (CMX)  

SciTech Connect

A multipactor discharge is a resonant condition for electrons in an alternating electric field. This discharge can be disruptive to RF circuits, cavities, and resonators by detuning the circuit and/or by seeding an arc with a partially developed multipactor discharge. The Coaxial Multipactor Experiment (CMX) investigates this discharge with goals of measuring the electron distribution, current, and absorbed power from the non-uniform RF field in coaxial transmission lines. CMX has a unique experimental setup which can support a multipactor discharge in a short section of continuous transmission line. A retarding potential analyzer with secondary electron suppression measures the multipactor electron distribution. Results depict a narrow, relatively high-energy distribution of electrons which exhibits energy dependence on frequency and not pressure below 1 mtorr. Each distribution has an energetic tail which extends to the maximum RF cavity voltage. Monte Carlo simulations reproduce the measured distributions and show dependence on the initial electron energy and phase distributions.

Graves, Timothy P.; LaBombard, B.; Wukitch, S.J.; Hutchinson, I.H. [MIT-PSFC, Cambridge, MA 02139 (United States)

2005-09-26

35

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

36

Bounds on Metamaterials Theoretical and Experimental Results  

Microsoft Academic Search

A dispersion relation for the combined effect of scattering and absorption of electromagnetic waves is employed. By invoking\\u000a the optical theorem, the result states that the extinction cross section integrated over all frequencies is related to the\\u000a static polarizability dyadics. In particular, it is established that the integrated extinction is the same for all materials\\u000a having identical static properties, irrespectively

Gerhard Kristensson; Christer Larsson; Christian Sohl; Mats Gustafsson

37

Rogowski coils: theory and experimental results.  

PubMed

The theory is given of the voltage output of a Rogowski coil excited by a current pulse flowing along the axis of the coil. In this theory the Rogowski coil is considered as a delay line. The results do not differ from those obtained usually by considering the coil as a voltage source dphi/dt with an inductive output impedance. Details are also given of the design of two Rogowski coils and their working modes are fully analyzed. PMID:18699628

Nassisi, V; Luches, A

1979-07-01

38

Numerical taxonomy on data: Experimental results  

SciTech Connect

The numerical taxonomy problems associated with most of the optimization criteria described above are NP - hard [3, 5, 1, 4]. In, the first positive result for numerical taxonomy was presented. They showed that if e is the distance to the closest tree metric under the L{sub {infinity}} norm. i.e., e = min{sub T} [L{sub {infinity}} (T-D)], then it is possible to construct a tree T such that L{sub {infinity}} (T-D) {le} 3e, that is, they gave a 3-approximation algorithm for this problem. We will refer to this algorithm as the Single Pivot (SP) heuristic.

Cohen, J.; Farach, M. [Rutgers Univ., Piscataway, NJ (United States)

1997-12-01

39

Experimental results for absolute cylindrical wavefront testing  

NASA Astrophysics Data System (ADS)

Applications for Cylindrical and near-cylindrical surfaces are ever-increasing. However, fabrication of high quality cylindrical surfaces is limited by the difficulty of accurate and affordable metrology. Absolute testing of such surfaces represents a challenge to the optical testing community as cylindrical reference wavefronts are difficult to produce. In this paper, preliminary results for a new method of absolute testing of cylindrical wavefronts are presented. The method is based on the merging of the random ball test method with the fiber optic reference test. The random ball test assumes a large number of interferograms of a good quality sphere with errors that are statistically distributed such that the average of the errors goes to zero. The fiber optic reference test utilizes a specially processed optical fiber to provide a clean high quality reference wave from an incident line focus from the cylindrical wave under test. By taking measurements at different rotation and translations of the fiber, an analogous procedure can be employed to determine the quality of the converging cylindrical wavefront with high accuracy. This paper presents and discusses the results of recent tests of this method using a null optic formed by a COTS cylindrical lens and a free-form polished corrector element.

Reardon, Patrick J.; Alatawi, Ayshah

2014-09-01

40

Experimental results on constructed wetland pilot system.  

PubMed

Research into a constructed wetland for wastewater treatment using M.H.E.A. (Hierarchical Mosaic of Artificial Ecosystems) pilot system was carried out over a vegetative period in 8 different flow and vegetable composition series. The system consisted of a free water pond as a first step working as primary treatment followed by a zone with Typha sp. and surface flow and finally a woody zone with a subsurface flow and planted with ligneous species (Salixsp., Populus sp., Fraxinus sp. and Alnus sp.). Removal efficiency in the study reflects an optimal result: 80-99% total suspended matter removal, 82-98% organic matter removal, 70-98% nutrients removal and up to 99.9% faecal bacterial disinfecting. Effluent characteristics were in accordance with European Union legislation criteria for wastewater treatment systems. PMID:11804123

Gonzlez, J M; Ansola, G; Luis, E

2001-01-01

41

Recent double beta decay experimental results  

SciTech Connect

Double beta decay experiments continue to contribute illuminating and constraining factors in the fields of nuclear and particle physics. Recently, there have been a number of half-life measurements realized for two-neutrino double beta decay candidates, often with data samples of high statistical significance. Searches for neutrinoless double beta decay and for new Majoron emitting decay modes have resulted in half-life limits only. For the zero-neutrino mode, these limits have pushed the Majorana neutrino mass to less than 1 eV. Currently, the generation of small source mass experiments is coming to an end. In the spirit of the {sup 76}Ge experiments, promising next generation research will need to study several kilograms of ultra-pure, isotopically-enriched double beta decay sources.

Sutton, C. Sean [Physics Department, Mount Holyoke College, South Hadley, Massachusetts 01075 (United States)

1997-05-20

42

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

43

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

44

Neutrinos from the Sun: experimental results confronted with solar models  

E-print Network

For standard neutrinos, recent solar neutrino results together with the assumption of a nuclearly powered Sun imply severe constraints on the individual components of the total neutrino flux: \\Phi_{Be}fusion chain towards the pp-I termination could be induced by a hypothetical low energy resonance in the He3+He3 reaction. This mechanism gives a somehow better, but still bad fit to the combined experimental data. We also discuss what can be learnt from new generation experiments about the properties of neutrinos and of the Sun.

Vittorio Castellani; Scilla Degl'innocenti; Gianni Fiorentini; Marcello Lissia; Barbara Ricci

1994-05-27

45

Theoretical and Experimental Results Regarding LENR/CF  

SciTech Connect

We challenge the predominant view that low-energy nuclear reactions (LENRs) are prohibited by standard quantum mechanics (QM). This view, supposedly based on standard nuclear theory, need not apply in condensed-matter environments. These considerations indicate that seemingly novel experimental evidence of rapid aneutronic bulk-process transmutation, at extraordinarily low-energy levels, in a simple electrochemical reactor, can occur. This explains: (a) induced rapid decay of radioactive thorium into stable nuclides, e.g., Cu and (b) resulting, anomalous distribution of Cu isotopes. We reexamine arguments of Peebles cited as evidence that standard QM 'forbids' cold fusion (CF). We note oversimplifications in those and present an alternative, more sophisticated calculation (see Bass, Refs. 3 through 8) demonstrating that conventional wisdom about impenetrability of the 'Coulomb barrier' fails as a result of periodic-order-induced resonance. We also examine empirical evidence. In three independent tests of an LENR electrolysis cell, using different I-V-T (current/voltage/time) protocols, the percentage of radiation reduction (RR) transmutation achieved {eta}=[23{percent}, 50{percent}, 83{percent}] versus expended energy E=[0.6535, 32.5, 74.6] (Watt-hours), obtained by numerical integration of recorded product I{center_dot}V for processing time T, provides near-perfect straight-line correlation: {eta}={alpha}{center_dot}E + {eta}{sub 0}, {alpha}=0.8105, {eta}{sub 0}=22.888, (0.65 < E < 0.75).

Robert W. Bass; Wm. Stan Gleeson

2000-11-12

46

Investigation of a Power Synchro System: Analysis and Experimental Results  

Microsoft Academic Search

An actual synchro system is examined with particular attention to dynamic behavior. Using frequency response and eigenvalue analysis, dynamic behavior is examined over a wide speed range. Experimental results obtained by frequency response measurements on the actual system are presented. Predicted values are correlated with experimental results and conclusions drawn regarding system performance, in particular concerning stability. Some steady-state results

Robert Burridge; Thomas Barton

1970-01-01

47

Numerical simulation of electromagnetic coupling and comparison with experimental results  

Microsoft Academic Search

A comparison between simulations using transmission line modeling (TLM) and experimental results is presented, with particular regard to problems in electromagnetic compatibility (EMC). Procedures for improved measurements and simulations inside a screened-room environment are discussed. Excellent agreement with the experimental results is found for simulations made using a variable mesh TLM technique

Alistair P. Duffy; Phillip Naylor; Trevor M. Benson; Christos Christopoulos

1993-01-01

48

Nuclear symmetry energy: An experimental overview  

E-print Network

The nuclear symmetry energy is a fundamental quantity important for studying the structure of systems as diverse as the atomic nucleus and the neutron star. Considerable efforts are being made to experimentally extract the symmetry energy and its dependence on nuclear density and temperature. In this article, we review experimental studies carried out up-to-date and their current status.

D. V. Shetty; S. J. Yennello

2010-02-01

49

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

50

Methods of experimentation with models and utilization of results  

NASA Technical Reports Server (NTRS)

The present report treats the subject of testing small models in a wind tunnel and of the methods employed for rendering the results constant, accurate and comparable with one another. Detailed experimental results are given.

Robert,

1924-01-01

51

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

52

Acoustic analysis in Mudejar-Gothic churches: experimental results.  

PubMed

This paper describes the preliminary results of research work in acoustics, conducted in a set of 12 Mudejar-Gothic churches in the city of Seville in the south of Spain. Despite common architectural style, the churches feature individual characteristics and have volumes ranging from 3947 to 10 708 m3. Acoustic parameters were measured in unoccupied churches according to the ISO-3382 standard. An extensive experimental study was carried out using impulse response analysis through a maximum length sequence measurement system in each church. It covered aspects such as reverberation (reverberation times, early decay times), distribution of sound levels (sound strength); early to late sound energy parameters derived from the impulse responses (center time, clarity for speech, clarity, definition, lateral energy fraction), and speech intelligibility (rapid speech transmission index), which all take both spectral and spatial distribution into account. Background noise was also measured to obtain the NR indices. The study describes the acoustic field inside each temple and establishes a discussion for each one of the acoustic descriptors mentioned by using the theoretical models available and the principles of architectural acoustics. Analysis of the quality of the spaces for music and speech is carried out according to the most widespread criteria for auditoria. PMID:15957758

Galindo, Miguel; Zamarreo, Tefilo; Girn, Sara

2005-05-01

53

Exclusive Dealing and Market Foreclosure: Further Experimental Results  

Microsoft Academic Search

This paper reports further experimental results on exclusive dealing contracts. We extend Landeo and Spier's (2009) work by studying Naked Exclusion in a strategic environment that involves a four-player, two-stage game. In addition to the roles of seller and buyers, our experimental environment includes the role of a potential entrant (a fourth passive player). Our findings are as follows. First,

Claudia M. Landeo; Kathryn E. Spier

2012-01-01

54

Theoretical and Experimental Results Regarding LENR\\/CF  

Microsoft Academic Search

We challenge the predominant view that low-energy nuclear reactions (LENRs) are prohibited by standard quantum mechanics (QM). This view, supposedly based on standard nuclear theory, need not apply in condensed-matter environments. These considerations indicate that seemingly novel experimental evidence of rapid aneutronic bulk-process transmutation, at extraordinarily low-energy levels, in a simple electrochemical reactor, can occur. This explains: (a) induced rapid

Robert W. Bass; Wm. Stan Gleeson

2000-01-01

55

Nuclear symmetry energy: An experimental overview  

Microsoft Academic Search

The nuclear symmetry energy is a fundamental quantity important for studying the structure of systems as diverse as the atomic\\u000a nucleus and the neutron star. Considerable efforts are being made to experimentally extract the symmetry energy and its dependence\\u000a on nuclear density and temperature. In this article, the experimental studies carried out up-to-date and their current status\\u000a are reviewed.

D. V. Shetty; S. J. Yennello

2010-01-01

56

Exclusive Dealing and Market Foreclosure: Further Experimental Results  

Microsoft Academic Search

This paper reports further experimental results on exclusive dealing contracts. We extend Landeo and Spiers [2009] work by studying Naked Exclusion in a strategic environment that involves a four-player, two-stage game. In addition to the roles of seller and buyers, our experimental environment includes the role of a potential entrant (a fourth passive player). Our findings are as follows. First,

Claudia Landeo; Kathryn Spier

2012-01-01

57

Energy Recovery LINAC: Experimental Challenges  

NASA Astrophysics Data System (ADS)

ERL projects are ongoing at JLab, Daresbury, KEK and Cornell. Here, we describe the experimental challenges of using high-coherence and ultra-fast pulses from the Cornell ERL and illustrate some potential opportunities. The Cornell ERL is designed to run in several different modes. In the hi-flux mode, the ERL runs at 5 GeV and 100 mA. Many experiments, such as inelastic x-ray scattering are photon-starved. In the high-coherence mode the ERL runs at 25 mA and the transverse emittances could be as low as 8 pm. The beam size will be at its smallest under this operating condition and an average spectral brightness as high as 10^23 (standard units) is predicted. We expect to produce a round (3 micron diameter) source for imaging and coherence experiments on individual biological cells. In the ultra-fast mode, the repetition rate is reduced from 1.3 GHz to 1 MHz, the bunch charge is increased to 1 nC per pulse, and the natural 2 ps bunch length is compressed to less than 100 femtoseconds. We will present opportunities for x-ray experiments on a single atom as well as the challenges in x ray optics, other experiments, and beam control issues when making a 1 nm focused x-ray beam size.

Brock, Joel

2007-03-01

58

A review of experimental results at the knee  

E-print Network

Results of experiments investigating air showers in the energy region of the knee are summarized. The all-particle energy spectrum, the mean logarithmic mass, and the average depth of the shower maximum will be discussed. Spectra for groups of elements from air shower data are compared to results from direct measurements.

Joerg R. Hoerandel

2005-07-31

59

Experimental Results for an Annular Aerospike with Differential Throttling  

NASA Technical Reports Server (NTRS)

Marshall Space Flight Center funded an internal study on Altitude Compensating Nozzles (ACN) for aerospike engines. The experimental hardware for the engine test is described in this viewgraph presentation, as well as the results of the experiment. The results include spike wall pressures, nozzle efficiency, and side force for four nozzle configurations.

Ruf, Joseph H.; McDaniels, David M.

2003-01-01

60

Light scattering by coated spheres: Experimental results and numerical simulations  

NASA Astrophysics Data System (ADS)

This work presents and compares experimental and numerical results obtained for the light scattered by micron-sized spherical particles (glass, silica) coated with non-absorbing and absorbing mantles (graphite, organic black paint). The comparison validates the use of light scattering studies for the determination of the physical parameters of dust particles, especially the determination of complex optical indices and thickness of absorbing mantles. This approach is of interest to validate experimental or numerical results, and to interpret remote light scattering observations, particularly those related to compact particles possibly covered with mantles.

Lasue, J.; Levasseur-Regourd, A. C.; Hadamcik, E.; Renard, J.-B.

2007-07-01

61

Planning by Adaptation: Experimental Results D. M. Lyons  

E-print Network

Planning by Adaptation: Experimental Results D. M. Lyons and A. J. Hendriks Philips Laboratories accepted [Bresina and Drummond, 1990, Fraichard and Laugier, 1991, McDermott, 1991]. In [Lyons et al., 1991. In subsequent papers, we looked at the theoretical issues of incre- mental adaptation [Lyons and Hendriks, 1992

Lyons, Damian M.

62

CSI sensing and control: Analytical and experimental results  

NASA Technical Reports Server (NTRS)

Recent work on structural identification and large-angle maneuvers with vibration suppression was presented. The recent work has sought to balance structural and controls analysis activities by involving the analysts directly in the validation and experimental aspects of the research. Some new sensing, actuation, system identification, and control concepts were successfully implemented. An overview of these results is given.

Junkins, J. L.; Pollock, T. C.; Rahman, Z. H.

1989-01-01

63

The yield strength of subliquidus basalts experimental results  

Microsoft Academic Search

Yield strength is an important property of particlefluid suspensions. In basaltic lavas that crystallize during flow emplacement, the onset of yield strength may result in threshold transitions in flow behavior and flow surface morphology. However, yield strengthcrystallinity relations are poorly known, particularly in geologic suspensions, where difficulties of experimental and field measurements have limited data acquisition in the subliquidus temperature

S. R Hoover; K. V Cashman; M Manga

2001-01-01

64

An Unmanned Planar Blimp on Visual Feedback Control : Experimental Results  

E-print Network

An Unmanned Planar Blimp on Visual Feedback Control : Experimental Results Yasunori Kawai1@t.kanazawa-u.ac.jp Abstract: In this paper, an unmanned planar blimp system using a visual feedback control is proposed. First, in the proposed unmanned planar blimp system. By applying feedback linearization techniques to the derived

65

Experimental results of a pulse position modulation infrared transceiver  

Microsoft Academic Search

Infrared technology is a suitable alternative for the support of indoor wireless local area networks (WLANs). When compared to radio technologies, infrared offers the potential for lower cost, higher security and better resilience to interference provoked by users from adjacent cells. This paper presents experimental results of an infrared transceiver for diffuse systems based on pulse position modulation. The implementation

Rui Valadas; Adriano Moreira; Carlos Oliveira; Luis Moreira; Cipriano Lomba; Antdnio Tavares; A. M. de Oliveira Duarte

1996-01-01

66

Experimental Results Related to Discrete Nonlinear Schrodinger Equations  

E-print Network

Experimental Results Related to Discrete Nonlinear Schr¨odinger Equations Mason A. Porter1 Oxford@maths.ox.ac.uk 1 Introduction Discrete nonlinear Schr¨odinger (DNLS) equations can be used to model nu- merous, the (contin- uous) nonlinear Schr¨odinger (NLS) equation provides a dispersive envelope wave model

Porter, Mason A.

67

Game Play in Engineering Education Concept and Experimental Results*  

E-print Network

Game Play in Engineering EducationÐ Concept and Experimental Results* BJARNE A. FOSS Department.foss@itk.ntnu.no TOR I. EIKAAS Cyberlab.Org AS, Trondheim, Norway Dynamic simulators combined with educational games of today's students obtained from extensive use of interactive computer games. This paper presents a design

Foss, Bjarne A.

68

Experimental results on the freezing of saturated sands  

NASA Astrophysics Data System (ADS)

Experimental freezings of two liquids (water and tert-amyl-alcohol) in sands were carried on in a closed system. A sand with known grain size distribution, mineralogic composition and physical properties has been used. An experimental apparatus reproducing a one dimensional heat transfer phenomenon was set up. The low plane was thermally insulated and the upper one was kept at constant temperature. A procedure of vibration of the sand was employed to have a uniform liquid regain distribution at the beginning of the cooling. Temperature was measured at different distances from the cold source during the cooling. Liquid regain distributions were measured at the end of the freezing process with the oven drying method. Conductive heat transfer with change of phase was theoretically investigated. The energy equation was solved numerically with the finite difference method of Crank. The thermal conductivity of the wet sand was determined.

Gori, F.; Ughi, M.

69

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

70

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)] [Airfoils, Inc., State College, PA (United States)

1997-01-01

71

Experimental results of a predictive neural network HVAC controller  

SciTech Connect

Proportional, integral, and derivative (PID) control is widely used in many HVAC control processes and requires constant attention for optimal control. Artificial neural networks offer the potential for improved control of processes through predictive techniques. This paper introduces and shows experimental results of a predictive neural network (PNN) controller applied to an unstable hot water system in an air-handling unit. Actual laboratory testing of the PNN and PID controllers show favorable results for the PNN controller.

Jeannette, E.; Assawamartbunlue, K.; Kreider, J.F. [Univ. of Colorado, Boulder, CO (United States); Curtiss, P.S. [Architectural Energy Corp., Boulder, CO (United States)

1998-12-31

72

Experimental results for a hypersonic nozzle/afterbody flow field  

NASA Technical Reports Server (NTRS)

This study was conducted to experimentally characterize the flow field created by the interaction of a single-expansion ramp-nozzle (SERN) flow with a hypersonic external stream. Data were obtained from a generic nozzle/afterbody model in the 3.5 Foot Hypersonic Wind Tunnel at the NASA Ames Research Center, in a cooperative experimental program involving Ames and McDonnell Douglas Aerospace. The model design and test planning were performed in close cooperation with members of the Ames computational fluid dynamics (CFD) team for the National Aerospace Plane (NASP) program. This paper presents experimental results consisting of oil-flow and shadow graph flow-visualization photographs, afterbody surface-pressure distributions, rake boundary-layer measurements, Preston-tube skin-friction measurements, and flow field surveys with five-hole and thermocouple probes. The probe data consist of impact pressure, flow direction, and total temperature profiles in the interaction flow field.

Spaid, Frank W.; Keener, Earl R.; Hui, Frank C. L.

1995-01-01

73

Novel Thermoelectric Modules for Cooling Powerful LEDs: Experimental Results  

NASA Astrophysics Data System (ADS)

We present the results of an experimental study of a cooling system based on a novel thermoelectric module specifically designed for thermal management of high-power light-emitting diodes (LEDs). The Seoul Semiconductor LED W724C0 device was chosen for experimental validation of the efficiency of the proposed cooling unit. Two cooling systems with identical heat sinks were tested for comparison: a state-of-the-art one based on an insulated metal substrate-printed circuit board (IMS-PCB), and a system with thermoelectric cooling. The obtained results show that use of thermoelectrics results in a considerable reduction of the LED operating temperature, providing increased light output and greatly increased LED lifetime.

Semenyuk, V.; Dekhtiaruk, R.

2013-07-01

74

Decompression craniectomy after traumatic brain injury: recent experimental results.  

PubMed

Among the secondary events occurring after traumatic brain injury (TBI) pathologically increased intracranial pressure (ICP) correlates most closely with poor outcome. In addition to infusion of hypertonic solutions, e.g. mannitol, and other medical measures, decompression of the brain by surgical removal of a portion of the cranium (craniectomy) has been used for many decades as an intuitive strategy for the treatment of post-traumatic ICP increase. The lack of evidence-based clinical and controversial experimental data, however, resulted in decompressive craniectomy to be recommended by most national and international guidelines only as a third tier therapy for the treatment of pathologically elevated ICP. Ongoing clinical trials on the use of decompressive craniectomy after TBI may clarify many aspects of the clinical application of this technique, however, some important pathophysiological issues, e.g. the timing of decompression craniectomy, its effect on brain edema formation, and its role for secondary brain damage, are still widely discussed and can only be addressed in experimental settings. The aim of the current review was therefore to summarize and discuss recent experimental data dealing with the use of decompression craniectomy following TBI. The present results suggest that surgical decompression effectively prevents secondary brain damage when performed early enough. Although caution should be taken when transferring conclusions drawn from experimental settings to the clinical situation, the current literature suggests that the timing of decompression may be of utmost importance in order to exploit the full neuroprotective potential of craniectomy following TBI. PMID:17618993

Plesnila, Nikolaus

2007-01-01

75

Experimental Results of Pebble Beds Thermal Hydraulic Characteristics  

SciTech Connect

The purpose of this paper is to present the results of the experimental investigation of the thermal hydraulic characteristics for two types of test sections - thin annular pebble beds (i.e. spheres dumped in thin annular slots) and pebble beds placed between cylinders. The experimental results of heat transfer from the spheres and from a cylinder, as well as hydraulic drag for both types of test sections are presented in this paper. The results of performed experiments in the case of thin annular pebble beds demonstrated that maximum heat transfer and hydraulic drag is at the relative width of the annular slot K equal to 1.07 and 1.75 of spheres diameter. The heat transfer in internal layers at these values of K is equal to the heat transfer in the internal layers of large (unlimited) rhombic packing. The results of the experimental investigation of pebble beds between cylinders demonstrated that the randomly arranged pebble bed is preferable to the regular rhombic structure from the point of view of design simplicity, heat transfer from the cylinder and drag coefficient. (authors)

Rimkevicius, S.; Uspuras, E. [Lithuanian Energy Institute, 3 Breslaujos str., LT-44403 Kaunas (Lithuania)

2006-07-01

76

High performance Doppler-inertial navigation-experimental results  

Microsoft Academic Search

This paper presents experimental results from a number of performance verification sea tests of the MARPOS(R) Doppler-inertial navigation system jointly implemented by Maridan A\\/S, Denmark, and the Technical University of Denmark for use onboard the MARIDAN series of AUVs. MARPOS(R) is a dead-reckoning based navigation system, the core of which is a state-of-the-art ring laser gyro (RLG) and a Doppler

Mikael Bliksted Larsen; Maridan AIS; Agem Alle

2000-01-01

77

Proteins in electric fields and pressure fields: experimental results.  

PubMed

Experimental results obtained by Stark effect and pressure tuning optical spectroscopy are discussed with the emphasis on studies aimed at unraveling the coupling of prosthetic groups to proteins. A comparative, detailed analysis is given concerning the coupling of the heme group to the apoprotein in various heme proteins based on spectral hole burning data. Electrochromism and electric dichroism experiments related to the coupling problem are also discussed in the context of other protein systems. PMID:9733987

Fidy, J; Balog, E; Khler, M

1998-08-18

78

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 Saloveys four-branch model of

Jane P Murray; Peter J Jordan; Neal M Ashkanasy

2006-01-01

79

Mechanical properties of triaxially braided composites: Experimental and analytical results  

NASA Technical Reports Server (NTRS)

The unnotched tensile properties of 2-D triaxial braid reinforced composites from both an experimental and an analytical viewpoint are studied. The materials are graphite fibers in an epoxy matrix. Three different reinforcing fiber architectures were considered. Specimens were cut from resin transfer molded (RTM) composite panels made from each braid. There were considerable differences in the observed elastic constants from different size strain gage and extensometer reading. Larger strain gages gave more consistent results and correlated better with the extensometer reading. Experimental strains correlated reasonably well with analytical predictions in the longitudinal, 0 degrees, fiber direction but not in the transverse direction. Tensile strength results were not always predictable even in reinforcing directions. Minor changes in braid geometry led to disproportionate strength variations. The unit cell structure of the triaxial braid was discussed with the assistance of computer analysis of the microgeometry. Photomicrographs of braid geometry were used to improve upon the computer graphics representations of unit cells. These unit cells were used to predict the elastic moduli with various degrees of sophistication. The simple and the complex analyses were generally in agreement but none adequately matched the experimental results for all the braids.

Masters, John E.; Foye, Raymond L.; Pastore, Christopher M.; Gowayed, Yasser A.

1992-01-01

80

Calculating an unknown source activity using modeled and experimental results.  

PubMed

A method is presented that provides a way to calculate the unknown activity of a source by using experimental exposure rate measurements from an ion chamber and exposure rates calculated using the MCNP radiation transport code. The method consists of fitting experimental data to MCNP results with both data sets in the form of (Equation is included in full-text article.)where r is the distance from the source at which the measurement was taken, X? is the exposure rate, and An is an assumed nominal activity of the source. The fit is done by calculating a correction factor for the nominal activity that shifts the experimental data to match the MCNP results. The actual activity of the source in question is found by multiplying the assumed nominal activity by the activity correction factor. The method was used to calculate the activities of the three Cs sources used in the Ohio Emergency Management Agency's instrument calibration range. It was found that the activities were less than the decay-corrected nominal activities by factors ranging from 3% to 10%. PMID:25271929

Rowan, Matthew S; Blue, Thomas E; Herminghuysen, Kevin

2014-11-01

81

Experimental results on the enhanced backscatter phenomenon and its dynamics  

NASA Astrophysics Data System (ADS)

Enhanced backscatter effects have long been predicted theoretically and experimentally demonstrated. The reciprocity of a turbulent channel generates a group of paired rays with identical trajectory and phase information that leads to a region in phase space with double intensity and scintillation index. Though simulation work based on phase screen models has demonstrated the existence of the phenomenon, few experimental results have been published describing its characteristics, and possible applications of the enhanced backscatter phenomenon are still unclear. With the development of commercially available high powered lasers and advanced cameras with high frame rates, we have successfully captured the enhanced backscatter effects from different reflection surfaces. In addition to static observations, we have also tilted and pre-distorted the transmitted beam at various frequencies to track the dynamic properties of the enhanced backscatter phenomenon to verify its possible application in guidance and beam and image correction through atmospheric turbulence. In this paper, experimental results will be described, and discussions on the principle and applications of the phenomenon will be included. Enhanced backscatter effects are best observed in certain levels of turbulence (Cn 2?10-13 m-2/3), and show significant potential for providing self-guidance in beam correction that doesn't introduce additional costs (unlike providing a beacon laser). Possible applications of this phenomenon include tracking fast moving object with lasers, long distance (>1km) alignment, and focusing a high-power corrected laser beam over long distances.

Wu, Chensheng; Nelson, William; Ko, Jonathan; Davis, Christopher C.

2014-10-01

82

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

83

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

84

Experimental results with ICRF on HANBIT mirror device  

NASA Astrophysics Data System (ADS)

ICRF is routinely used for plasma production in HANBIT mirror machine with a slot antenna. Second ICRF system has been installed for ion heating with slow wave in the central cell. Initial experiments showed electron temperature increases in the edge region. ICRF was also found to be very effective to stabilize the interchange mode by inducing ponderomotive force. Without any stabilizing mechanisms, a very stable plasma can be obtained with ICRF only. A simulation code has been developed to understand the HANBIT ICRF discharges and the electric field data calculated from this code is used for estimating ponderomotive forces. The results show qualitatively good agreement with experimental observations. .

HANBIT Team

2001-10-01

85

Experimental Measurement of Low Energy Neutrino Interactions  

SciTech Connect

Neutrino interactions in the few to few tens of MeV range are of importance for several physics topics, including solar, supernova and reactor neutrinos, as well as future proposed oscillation and Standard Model test experiments. Although interaction cross-sections for some simple targets are well understood, very little experimental data exist for interactions with nuclei. This talk will discuss the motivation for measuring low energy neutrino interactions, the state of knowledge, and possible future strategies.

Scholberg, Kate [Duke University, Durham, NC, 27708 (United States)

2011-11-23

86

Simulated moving bed under linear conditions: Experimental vs. calculated results  

SciTech Connect

A simulated moving bed (SMB) was operated for the separation of mixtures of 2-phenyl ethanol and 3-phenyl-l-propanol on columns packed with Zorbax C18 bonded silica, using a 60:409 (v/v) solution of methanol and water as the mobile phase. Series of four or eight columns were used. The experiments were carried out with low concentration mixtures, that is, under linear conditions. Band profiles of both compounds eluted from one of the columns during successive periods after steady state had been reached were recorded, as were the concentration histories at the extract and raffinate ports. These experimental results are compared to those predicted by two models: the linear ideal and the linear equilibrium-dispersive models of chromatography, applied to the SMB separator. These two models give excellent agreement between the experimental profiles and those calculated with the model. As expected, the profiles predicted by the ideal and the equilibrium-dispersive models differ only by the lack of dispersion in the profiles given by the former. The latter model is demonstrated to be a solid, reliable tool for further studies of the SMB design and optimization.

Yun, T.; Zhong, G.; Guiochon, G. [Univ. of Tennessee, Knoxville, TN (United States)] [Univ. of Tennessee, Knoxville, TN (United States)

1997-04-01

87

Guided waves in elastic plates with Gaussian section variation: experimental and numerical results.  

PubMed

Experimental and numerical results are presented on the behavior of guided waves in elastic plates in plane strain that include a Gaussian variation of their section, located between two areas of constant thickness. The area of varying section is wide compared to the used wavelengths, which allows wave propagation inside this area. The experimental results show that an incident Lamb wave is indeed converted into an adiabatic wave inside the varying section domain. A trapped wave in the Gaussian domain is also observed, depending on the incident mode and on the Gaussian maximum height. Outside the varying section domain, conversion into different Lamb waves is observed. This conversion phenomenon is experimentally quantified by the measurement of the Lamb wave normal displacement and of its carried energy. A numerical study, based on the Finite Elements Method is performed, and successfully compared to the experimental results. PMID:17659314

Marical, P; El-Kettani, M Ech-Cherif; Predoi, M V

2007-12-01

88

Beta decay and the origins of biological chirality - Experimental results  

NASA Technical Reports Server (NTRS)

Preliminary experimental results are presented of an investigation of the possible role of preferential radiolysis by electrons emitted in the beta decay of radionuclides, a parity-nonconserving process, in the universal causation of the optical activity of biological compounds. Experiments were designed to measure the asymmetry in the production of triplet positronium upon the bombardment of an amino acid powder target by a collimated beam of positrons as positron helicity or target chirality is reversed. No asymmetry down to a level of 0.0007 is found in experiments on the D and L forms of cystine and tryptophan, indicating an asymmetry in positronium formation cross section of less than 0.01, while an asymmetry of 0.0031 is found for leucine, corresponding to a formation cross section asymmetry of about 0.04

Gidley, D. W.; Rich, A.; Van House, J.; Zitzewitz, P. W.

1982-01-01

89

Solving and Learning Soft Temporal Constraints: Experimental Setting and Results  

NASA Technical Reports Server (NTRS)

Soft temporal constraints problems allow to describe in a natural way scenarios where events happen over time and preferences are associated to event distances and durations. However, sometimes such local preferences are difficult to set, and it may be easier instead to associate preferences to some complete solutions of the problem. Machine learning techniques can be useful in this respect. In this paper we describe two solvers (one more general and the other one more efficient) for tractable subclasses of soft temporal problems, and we show some experimental results. The random generator used to build the problems on which tests are performed is also described. We also compare the two solvers highlighting the tradeoff between performance and representational power. Finally, we present a learning module and we show its behavior on randomly-generated examples.

Rossi, F.; Sperduti, A.; Venable, K. B.; Khatib, L.; Morris, P.; Morris, R.; Clancy, Daniel (Technical Monitor)

2002-01-01

90

Experimental results from an Imarad 88 pixellated CZT detector  

Microsoft Academic Search

This paper reports experimental results obtained from an 88 pixellated CZT detector provided by Imarad Imaging Systems. Three arbitrarily selected pixels were independently tested using ? rays of different energies. The signals from an anode pixel and the cathode were read out simultaneously. From the observations of the pulse waveforms from both the anode pixel and the cathode, the electron-injection

W. Li; Z. He; G. F. Knoll; D. K. Wehe; J. E. Berry

2001-01-01

91

Wavelength optimization in femtosecond laser corneal surgery: experimental results  

NASA Astrophysics Data System (ADS)

Femtosecond laser surgery in the volume of corneal tissue is difficult in the case of oedematous or pathological corneas: in those corneas, the propagation of the laser beam is perturbed by the optical scattering. This phenomenon can be greatly reduced by using a better suited laser wavelength. A series of ex vivo surgical experiments has been conducted at wavelengths around 1600 nm. The results have been compared to experiments performed at 800 nm and 1000 nm. We have compared penetration depth and incision quality as a function of wavelength and energy.

Crotti, C.; Deloison, F.; Peyrot, D. A.; Savoldelli, M.; Legeais, J.-M.; Roger, F.; Plamann, K.

2009-07-01

92

Experimental Progress and Results of a Visible Nulling Coronagraph  

NASA Technical Reports Server (NTRS)

The crux of visible exoplanet detection is overcoming significant star-planet contrast ratios on the order of 10(exp -7) to 10(exp -10)-at very small angular separations. We are developing an interferometric nulling coronagraph designed to achieve a 10(exp -6) contrast ratio at a working science bandpass of 20% visible light. Achieving large, broadband suppression requires a pseudo-achromatic phase flip, while maintaining a strict error budget. Recent results from our nulling interferometer testbed yield contrast ratios at the 1.05x10(exp -6) level, with a 15% visible bandpass. This result is at 65% of our final bandpass requirement, although limitations of our current configuration make major hardware changes essential to broadening the bandpass. We make the argument that broadening the bandpass should not necessarily adversely affect the null depth until beyond the 20% visible light level. Using the same setup we are able to reach monochromatic null depths of 1.11x10(exp -7) (?= 638 nm)averaged over three seconds. This paper will describe our experimental approach for achieving deep broadband nulls, as well as error considerations and limitations, and the most recent results for our nulling coronagraph testbed.

Samuele, Rocco; Wallace, J. Kent; Schmidtlin, Edouard; Shao, Mike; Levine, B. Martin; Fregoso, Santos

2007-01-01

93

[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

94

Insulator-based dielectrophoresis of microorganisms: theoretical and experimental results.  

PubMed

Dielectrophoresis (DEP) is the motion of particles due to polarization effects in nonuniform electric fields. DEP has great potential for handling cells and is a non-destructive phenomenon. It has been utilized for different cell analysis, from viability assessments to concentration enrichment and separation. Insulator-based DEP (iDEP) provides an attractive alternative to conventional electrode-based systems; in iDEP, insulating structures are used to generate nonuniform electric fields, resulting in simpler and more robust devices. Despite the rapid development of iDEP microdevices for applications with cells, the fundamentals behind the dielectrophoretic behavior of cells has not been fully elucidated. Understanding the theory behind iDEP is necessary to continue the progress in this field. This work presents the manipulation and separation of bacterial and yeast cells with iDEP. A computational model in COMSOL Multiphysics was employed to predict the effect of direct current-iDEP on cells suspended in a microchannel containing an array of insulating structures. The model allowed predicting particle behavior, pathlines and the regions where dielectrophoretic immobilization should occur. Experimental work was performed at the same operating conditions employed with the model and results were compared, obtaining good agreement. This is the first report on the mathematical modeling of the dielectrophoretic response of yeast and bacterial cells in a DC-iDEP microdevice. PMID:21853448

Moncada-Hernandez, Hector; Baylon-Cardiel, Javier L; Prez-Gonzlez, Victor H; Lapizco-Encinas, Blanca H

2011-09-01

95

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

96

Experimental Results of Integrated Refrigeration and Storage System Testing  

NASA Technical Reports Server (NTRS)

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 close cycle Brayton refrigerator to remove energy from the stored cryogenic propellant. This allows for the potential of a zero loss storage and transfer system, as well and control of the state of the propellant through densification or re-liquefaction. However, the behavior of the fluid in this type of system is different than typical cryogenic behavior, 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 thermo fluid 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. KEYWORDS: Liquid Oxygen, Refrigeration, Storage

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

2009-01-01

97

Experimental evidence that evolutionarily diverse assemblages result in higher productivity  

PubMed Central

There now is ample experimental evidence that speciose assemblages are more productive and provide a greater amount of ecosystem services than depauperate ones. However, these experiments often conclude that there is a higher probability of including complementary species combinations in assemblages with more species and lack a priori prediction about which species combinations maximize function. Here, I report the results of an experiment manipulating the evolutionary relatedness of constituent plant species across a richness gradient. I show that assemblages with distantly related species contributed most to the higher biomass production in multispecies assemblages, through species complementarity. Species produced more biomass than predicted from their monocultures when they were in plots with distantly related species and produced the amount of biomass predicted from monoculture when sown with close relatives. This finding suggests that in the absence of any other information, combining distantly related species in restored or managed landscapes may serve to maximize biomass production and carbon sequestration, thus merging calls to conserve evolutionary history and maximize ecosystem function. PMID:23674676

Cadotte, Marc W.

2013-01-01

98

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

99

Bolus-tracking arterial spin labelling: theoretical and experimental results  

NASA Astrophysics Data System (ADS)

Arterial spin labelling (ASL) is a magnetic resonance imaging (MRI) technique that can be used to provide a quantitative assessment of cerebral perfusion. Despite the development of a number of theoretical models to facilitate quantitative ASL, some key challenges still remain. The purpose of this study is to develop a novel quantitative ASL method based on a macroscopic model that reduces the number of variables required to describe the physiological processes involved. To this end, a novel Fokker-Planck equation consisting of stochastically varying macroscopic variables was derived from a general Langevin equation. ASL data from the rat brain was acquired using a bolus-tracking ASL protocol where a bolus of labelled spins flowing from an inversion plane in the neck into an imaging plane in the brain can be observed. Bolus durations of 1.5 s, 2.0 s and 3.0 s were used and the solution to the Fokker-Planck equation for the boundary conditions of bolus-tracking ASL was fitted to the experimental data using a least-squares fit. The mean transit time (MTT) and capillary transit time (CTT) were calculated from the first and second moments of the resultant curve respectively and the arterial transit time (ATT) was calculated by subtracting the CTT from the MTT. The average MTT, CTT and ATT values were 1.75 0.22 s, 1.43 0.12 s and 0.32 0.04 s respectively. In conclusion, a new ASL protocol has been developed by combining the theoretical model with ASL experiments. The technique has the unique ability to provide solutions for varying bolus volumes and the generality of the new model is demonstrated by the derivation of additional solutions for the continuous and pulsed ASL (CASL and PASL) techniques.

Kelly, M. E.; Blau, C. W.; Kerskens, C. M.

2009-03-01

100

Amplified energy harvester from footsteps: design, modeling, and experimental analysis  

NASA Astrophysics Data System (ADS)

This paper presents the design, modeling and experimental analysis of an amplified footstep energy harvester. With the unique design of amplified piezoelectric stack harvester the kinetic energy generated by footsteps can be effectively captured and converted into usable DC power that could potentially be used to power many electric devices, such as smart phones, sensors, monitoring cameras, etc. This doormat-like energy harvester can be used in crowded places such as train stations, malls, concerts, airport escalator/elevator/stairs entrances, or anywhere large group of people walk. The harvested energy provides an alternative renewable green power to replace power requirement from grids, which run on highly polluting and global-warming-inducing fossil fuels. In this paper, two modeling approaches are compared to calculate power output. The first method is derived from the single degree of freedom (SDOF) constitutive equations, and then a correction factor is applied onto the resulting electromechanically coupled equations of motion. The second approach is to derive the coupled equations of motion with Hamilton's principle and the constitutive equations, and then formulate it with the finite element method (FEM). Experimental testing results are presented to validate modeling approaches. Simulation results from both approaches agree very well with experimental results where percentage errors are 2.09% for FEM and 4.31% for SDOF.

Wang, Ya; Chen, Wusi; Guzman, Plinio; Zuo, Lei

2014-04-01

101

Selected problems in experimental intermediate energy physics  

SciTech Connect

The objectives of this research program are to: investigate forefront problems in experimental intermediate energy physics; educate students in this field of research; and, develop the instrumentation necessary to undertake this experimental program. Generally, the research is designed to search for physical processes which cannot be explained by conventional models of elementary interactions. This includes the use of nuclear targets where the nucleus provides a many body environment of strongly perturbation of a known interaction by this environment. Unfortunately, such effects may be masked by the complexity of the many body problem and may be difficult to observe. Therefore, experiments must be carefully chosen and analyzed for deviations from the more conventional models. There were three major thrusts of the program; strange particle physics, where a strange quark is embedded in the nuclear medium; muon electro-weak decay, which involves a search for a violation of the standard model of the electro-weak interaction; and measurement of the spin dependent structure function of the neutron.

Mayes, B.W.; Hungerford, E.V.; Pinsky, L.S.

1990-09-01

102

Vortex Threshold: Experimental Results at Martian Atmospheric Pressures  

NASA Astrophysics Data System (ADS)

Many examples of Martian dust devils and tracks left by their passage have been identified in Viking and Mars Orbital Camera images and inferred from lander data (Viking and Mars Pathfinder). Recent surveys suggest that dust devils may be common phenomena on Mars and, unlike Earth, could contribute significantly to the global dust budget. Previous studies have noted the apparent paradox that Martian airborne dust is abundant and only a few microns in diameter yet experiments at Mars pressures suggest current Martian ambient wind speeds are insufficient to lift such fine particles from the surface; speeds of the order of 10s or even 100s of m/s are required. Local wind speeds within terrestrial dust devils are typically much greater than ambient wind speeds, but we have no in-situ measurements of the velocity structure of Mars dust devils and so cannot directly quantify their ability to entrain material. However, by using laboratory simulations we can directly measure the ability of a vortex to lift material of known size and density under a variety of atmospheric pressures. We have constructed a vortex generator consisting of a large vertical cylinder containing a rotor comprising four vertical blades and capable of speeds up to 4500 RPM. Beneath the cylinder is a 2.4 by 2.4 m tabletop which can be covered in particles for threshold tests or instrumented with pressure transducers to measure the pressure structure of the vortex. The distance between the cylinder and the tabletop and the height of the blades within the cylinder can be varied to generate a wide range of geometries and intensities of vortices. Recently, the apparatus has been operated at the NASA-Ames Research Center Mars Surface Wind Tunnel facility to simulate Martian atmospheric conditions. We have measured vortex `saltation' threshold using many types of particles ranging in density from walnut shells (1.1 kg/m-3) to steel grit (7.6 kg/m-3) with particle sizes from 2 to 2000 microns and using atmospheric pressures ranging from 10 mbar (representing current Mars atmospheric conditions) to ambient. As expected, vortex threshold was more difficult to achieve with lower pressure conditions. Only the `optimum' particles (those with low densities and particle sizes ranging from 70 to 350 micron) reached full `saltation' at 10 mbar pressure before the apparatus speed limit was reached. Our results suggest that vortex threshold is directly analogous to boundary layer shear threshold for sand-sized particles at pressure from 65 mbar to ambient. We have used this result to equate vortex and boundary layer results in the sand-sized particle regime and hence to compare vortex threshold data with boundary layer results for smaller particles and lower pressures. We used empirical boundary layer expressions for threshold (corrected for particle size and particle Reynold's number). In all cases, vortex action appears more efficient than boundary layer winds at lifting small dust-sized particles and at lifting all particles at very low pressure. We conclude that Martian dust devils are more efficient mechanisms for particle entrainment than boundary layer winds, not merely because they have enhanced local wind speeds but also through another intrinsic mechanism. We suggest that a lift force caused by the passage of the low-pressure core of the dust devil over the particles would have such an effect and present examples of experimental `pressure-well' measurements at low pressures to support this.

Balme, M.; Greeley, R.; Phoreman, J.; Iversen, J.; Mickelson, B.; Beardmore, G.; Metzger, S.

2002-12-01

103

Alkali Metal Backup Cooling for Stirling Systems - Experimental Results  

NASA Technical Reports Server (NTRS)

In a Stirling Radioisotope Power System (RPS), heat must be continuously removed from the General Purpose Heat Source (GPHS) modules to maintain the modules and surrounding insulation at acceptable temperatures. The Stirling convertor normally provides this cooling. If the Stirling convertor stops in the current system, the insulation is designed to spoil, preventing damage to the GPHS at the cost of an early termination of the mission. An alkali-metal Variable Conductance Heat Pipe (VCHP) can be used to passively allow multiple stops and restarts of the Stirling convertor. In a previous NASA SBIR Program, Advanced Cooling Technologies, Inc. (ACT) developed a series of sodium VCHPs as backup cooling systems for Stirling RPS. The operation of these VCHPs was demonstrated using Stirling heater head simulators and GPHS simulators. In the most recent effort, a sodium VCHP with a stainless steel envelope was designed, fabricated and tested at NASA Glenn Research Center (GRC) with a Stirling convertor for two concepts; one for the Advanced Stirling Radioisotope Generator (ASRG) back up cooling system and one for the Long-lived Venus Lander thermal management system. The VCHP is designed to activate and remove heat from the stopped convertor at a 19 degC temperature increase from the nominal vapor temperature. The 19 degC temperature increase from nominal is low enough to avoid risking standard ASRG operation and spoiling of the Multi-Layer Insulation (MLI). In addition, the same backup cooling system can be applied to the Stirling convertor used for the refrigeration system of the Long-lived Venus Lander. The VCHP will allow the refrigeration system to: 1) rest during transit at a lower temperature than nominal; 2) pre-cool the modules to an even lower temperature before the entry in Venus atmosphere; 3) work at nominal temperature on Venus surface; 4) briefly stop multiple times on the Venus surface to allow scientific measurements. This paper presents the experimental results from integrating the VCHP with an operating Stirling convertor and describes the methodology used to achieve their successful combined operation.

Schwendeman, Carl; Tarau, Calin; Anderson, William G.; Cornell, Peggy A.

2013-01-01

104

Alkali Metal Backup Cooling for Stirling Systems - Experimental Results  

NASA Technical Reports Server (NTRS)

In a Stirling Radioisotope Power System (RPS), heat must be continuously removed from the General Purpose Heat Source (GPHS) modules to maintain the modules and surrounding insulation at acceptable temperatures. The Stirling convertor normally provides this cooling. If the Stirling convertor stops in the current system, the insulation is designed to spoil, preventing damage to the GPHS at the cost of an early termination of the mission. An alkali-metal Variable Conductance Heat Pipe (VCHP) can be used to passively allow multiple stops and restarts of the Stirling convertor. In a previous NASA SBIR Program, Advanced Cooling Technologies, Inc. (ACT) developed a series of sodium VCHPs as backup cooling systems for Stirling RPS. The operation of these VCHPs was demonstrated using Stirling heater head simulators and GPHS simulators. In the most recent effort, a sodium VCHP with a stainless steel envelope was designed, fabricated and tested at NASA Glenn Research Center (GRC) with a Stirling convertor for two concepts; one for the Advanced Stirling Radioisotope Generator (ASRG) back up cooling system and one for the Long-lived Venus Lander thermal management system. The VCHP is designed to activate and remove heat from the stopped convertor at a 19 C temperature increase from the nominal vapor temperature. The 19 C temperature increase from nominal is low enough to avoid risking standard ASRG operation and spoiling of the Multi-Layer Insulation (MLI). In addition, the same backup cooling system can be applied to the Stirling convertor used for the refrigeration system of the Long-lived Venus Lander. The VCHP will allow the refrigeration system to: 1) rest during transit at a lower temperature than nominal; 2) pre-cool the modules to an even lower temperature before the entry in Venus atmosphere; 3) work at nominal temperature on Venus surface; 4) briefly stop multiple times on the Venus surface to allow scientific measurements. This paper presents the experimental results from integrating the VCHP with an operating Stirling convertor and describes the methodology used to achieve their successful combined operation.

Schwendeman, Carl; Tarau, Calin; Anderson, William G.; Cornell, Peggy A.

2013-01-01

105

Experimental Results in DBD Plasma Actuators for Air Flow Control  

Microsoft Academic Search

In this paper, several planar dielectric barrier discharge fluid-dynamics actuators have been experimentally investigated. The actuator is made by an electrode pair separated by a dielectric. It is characterized by a planar geometry, and it induces a volume force on the gas above it which modifies the fluid dynamics within the aerodynamic boundary layer. Several actuator geometries, dielectric materials, ac

Gabriele Neretti; Andrea Cristofolini; Carlo A. Borghi; Alessandro Gurioli; Roberto Pertile

2012-01-01

106

Experimental results on combined ultraviolet-proton excitation of moon rock luminescence.  

NASA Technical Reports Server (NTRS)

The experimental results reported indicate that a small synergistic effect may exist between near-UV radiation and solar-wind-energy protons in solar radiation that could slightly enhance luminescence generation on the moon's surface. The magnitude of the effect, however, is far too small to account for the apparent orders-of-magnitude discrepancy between reported telescope measurements of lunar luminescence and the limitation of lunar luminescence intensity based on lab studies of moon rocks.

Nash, D. B.

1973-01-01

107

Experimental Results for an Annular Aerospike with Differential Throttling  

NASA Technical Reports Server (NTRS)

A) MSFC funded an internal study on Altitude Compensating Nozzles: 1) Develop an ACN design and performance prediction tool. 2) Design, build and test cold flow ACN nozzles. 3) An annular aerospike nozzle was designed and tested. 4) Incorporated differential throttling to assess Thrust Vector Control. B) Objective of the test hardware: 1) Provide design tool verification. 2) Provide benchmark data for CFD calculations. 3) Experimentally measure side force, or TVC, for a differentially throttled annular aerospike.

Ruf, Joseph H.; McDaniels, David M.

2005-01-01

108

CP Violation in B Meson Decays: Experimental Results  

SciTech Connect

CP violation is intimately connected with the puzzle of matter-antimatter asymmetry and baryogenesis. In the Standard Model of particle physics, the observed CP violation phenomena are accounted for by the Cabibbo-Kobayashi-Maskawa mechanism involving a phase in the quark mixing matrix. This paper is devoted to a review of the experimental status of CP violation in the decays of B mesons.

Lanceri, Livio; /Trieste U. /INFN, Trieste

2005-08-30

109

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

SciTech Connect

Recent experimental results, supporting simulations, and design modeling are presented from a developmental effort to a produce a long pulse ({approximately}1{mu}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, K.G.; Crouch, D.D.; Sar, D.R.; Speciale, R.A. [Hughes Missile Systems Co., Rancho Cucamonga, CA (United States); Carlsten, B.E.; Fazio, M.V.; Haynes, W.B.; Stringfield, R.M. [Los Alamos National Lab., NM (United States)

1994-12-31

110

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

111

Interaction noise mechanisms for an advanced propeller - Experimental results  

NASA Astrophysics Data System (ADS)

The interaction mechanisms associated with wakes incident upon rotating propfan blades are presently studied experimentally in order to generate a database for the improvement of noise-prediction methodology components and achieve a deeper understanding of interaction-noise generation. A single, stationary, swept fan blade representative of a state-of-the-art profan was used to generate a wake upstream of a single-rotating propfan and gather interaction noise measurements. A potentially dominant interaction noise-source mechanism, related to a velocity defect associated with the leading edge vortex of the swept blade, was identified. This vortex defect/blade interaction generated significant blade surface pressure fluctuations.

Simonich, J. C.; McCormick, D. C.; Lavrich, P. L.

1989-04-01

112

Optimal active vibration absorber: Design and experimental results  

NASA Technical Reports Server (NTRS)

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.

1992-01-01

113

Dark Matter or Neutrino recoil? Interpretation of Recent Experimental Results  

E-print Network

The elastic nuclear recoil signal, being under intense scrutiny by multiple underground experiments, can be interpreted either as coming from the interaction of nuclei with WIMP dark matter or from the scattering of new species of MeV-energy neutrinos. The most promising model for the latter case is a neutrino $\

Maxim Pospelov; Josef Pradler

2013-11-22

114

Titanium as reactor material for SCWO applications. First experimental results  

SciTech Connect

According to literature data, nickel base alloys are not sufficiently corrosion resistant in chloride bearing SCWO environments. Titanium was proposed several times as a suitable material for the construction of a corrosion resistant reactor. Titanium does not show the required mechanical strength for high temperature high pressure applications and it can only be used to form liners for an SCWO apparatus. Therefore, pressure tubes made of alloy 625 were lined with titanium grade 2. Additionally corrosion tests with coupons made of titanium grades 2, 5, 7, 12 and {beta}-C were performed. The coupons were placed inside an alumina-lined reactor. Materials were exposed to simulated SCWO feeds consisting of water, oxygen and HCl, H{sub 2}SO{sub 4}, or H{sub 3}PO{sub 4}. Experimental temperatures were up to 600 C, pressures up to 27 MPa and experimental times up to 200 hours. Corrosion in chloride containing solution is low. In the presence of sulfate or phosphate, corrosion of titanium grade 2 becomes severe. For these environments an upper limit of the corrosion rate could be estimated.

Boukis, N.; Friedrich, C.; Dinjus, E. [Forschungszentrum Karlsruhe (Germany)

1998-12-31

115

Medical waste to energy: experimental study  

PubMed Central

SUMMARY Objective. Although waste is traditionally assessed as a pollutant which needs to be reduced or lessened, its management is certainly necessary. Nowadays, biological fuel cells, through the direct conversion of organic matter to electricity using biocatalysts, represent a technology able to produce sustainable energy by means of waste treatment. This study aims to propose a mean to generate energy from blood and saliva, that are common risk-infectious medical waste. Materials and methods. Material employed (purchased by Sigma-Aldrich) were: Glucose oxidase (GOx), Nafion perfluorinated resin solution at 5% in a mixture of lower aliphatic alcohols and water, Polyethylene oxide. Stock solutions of D (+) glucose were prepared in a 0.1 M phosphate buffer solution and stored at 4 C for at least 24 h before use. Carbon cloth electrode ELAT HT 140 E-W with a platinum loading of 5 gm-2 was purchased by E-Tek. Electrospun Nafion fibers were obtained as follows. Scanning electron microscopy was used to characterize the electrode morphologies. Results. In order to develop an effective immobilization strategy of GOx on the electrode surface, Nafion fibers (a fully fluorinated ion conducting polymer used as a membrane material in enzymatic fuel cells - EFC) were selected as immobilizing polymer matrix. In this work, exploiting the nafion fibers capability of being able to cathalize Gox activity, we have tried to produce an enzymatic fuel cell which could produce energy from the blood and the saliva within medical-dental waste. Conclusions. Medical waste refers to all those materials produced by the interaction among doctor and patient, such as blood and saliva. During our research we will try to complete an EFC prototype able to produce energy from blood and saliva inside the risk-infectious medical waste in order to contribute to the energy requirements of a consulting room. PMID:24971161

ARCURI, C.; LUCIANI, F.; PIVA, P.; BARTULI, F.N.; OTTRIA, L.; MECHERI, B.; LICOCCIA, S.

2013-01-01

116

Fracture mechanics analysis of composite microcracking - Experimental results in fatigue  

NASA Technical Reports Server (NTRS)

The Nairn (1989) variational mechanics analysis, which yields the energy release rate of a microcrack's formation between two existing microcracks, has proven useful in the fracture mechanics interpretation of cross-ply laminates' microcracking. Attention is presently given to the application of this energy release rate analysis to a fracture mechanics-based interpretation of microcrack formation during fatigue loading, for the case of fatigue experiments on three layups of Avimid K/IM6 laminates and four layups of Fiberite 934/T300 laminates. The single master Paris-law plot onto which the data from all layups of a given material system fall is claimed to offer a complete characterization of that system's microcrack-formation resistance during fatigue loading.

Nairn, J. A.; Liu, S.

1990-01-01

117

Construction of a WMR for Trajectory Tracking Control: Experimental Results  

PubMed Central

This paper reports a solution for trajectory tracking control of a differential drive wheeled mobile robot (WMR) based on a hierarchical approach. The general design and construction of the WMR are described. The hierarchical controller proposed has two components: a high-level control and a low-level control. The high-level control law is based on an input-output linearization scheme for the robot kinematic model, which provides the desired angular velocity profiles that the WMR has to track in order to achieve the desired position (x?, y?) and orientation (??). Then, a low-level control law, based on a proportional integral (PI) approach, is designed to control the velocity of the WMR wheels to ensure those tracking features. Regarding the trajectories, this paper provides the solution or the following cases: (1) time-varying parametric trajectories such as straight lines and parabolas and (2) smooth curves fitted by cubic splines which are generated by the desired data points {(x1?, y1?),..., (xn?, yn?)}. A straightforward algorithm is developed for constructing the cubic splines. Finally, this paper includes an experimental validation of the proposed technique by employing a DS1104 dSPACE electronic board along with MATLAB/Simulink software. PMID:23997679

Silva-Ortigoza, R.; Marquez-Sanchez, C.; Marcelino-Aranda, M.; Marciano-Melchor, M.; Silva-Ortigoza, G.; Bautista-Quintero, R.; Ramos-Silvestre, E. R.; Rivera-Diaz, J. C.; Munoz-Carrillo, D.

2013-01-01

118

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

119

Recent Experimental Results in the VX-10 Device  

NASA Astrophysics Data System (ADS)

In the VASIMR engine, neutral gas is ionized using a helicon type source and the ions are subsequently accelerated via ICRF power injection. The experimental device in the ASPL is targeting a total RF power level of 10 kW and is called VX-10. RF power is available with 3 kW at 25 MHz for the helicon source and 100 kW at 3 MHz for ICRF. Experiments with light gasses (hydrogen, deuterium, and helium) are performed. The VX-10 3-magnet system is capable of a maximum B field of 2 T and has flexible axial profile shaping capability. Diagnostics in the plasma exhaust include an RF compensated Langmuir probe, a Mach probe, Retarding Potential Analyzer (RPA), newly installed density interferometer and an ion gauge neutral pressure measurement. Parametric (e.g. magnetic field, gas flow, and RF power) studies are presented. Data indicate ion heating to more than 1 eV and acceleration by the magnetic exhaust with the helicon alone. ICRF experiments are beginning and initial data are presented.

Squire, J. P.; Daz, F. R. Chang; Jacobson, V. T.; McCaskill, G. E.; McCoy, J. E.; Petro, A. J.; Baity, F. W.; Bengtson, R. D.; Bering, E. A.; Garret, J. A.; Glover, T. W.

2000-10-01

120

Construction of a WMR for trajectory tracking control: experimental results.  

PubMed

This paper reports a solution for trajectory tracking control of a differential drive wheeled mobile robot (WMR) based on a hierarchical approach. The general design and construction of the WMR are described. The hierarchical controller proposed has two components: a high-level control and a low-level control. The high-level control law is based on an input-output linearization scheme for the robot kinematic model, which provides the desired angular velocity profiles that the WMR has to track in order to achieve the desired position (x?, y?) and orientation (??). Then, a low-level control law, based on a proportional integral (PI) approach, is designed to control the velocity of the WMR wheels to ensure those tracking features. Regarding the trajectories, this paper provides the solution or the following cases: (1) time-varying parametric trajectories such as straight lines and parabolas and (2) smooth curves fitted by cubic splines which are generated by the desired data points {(x??, y??),..., (x(n)?, y(n)?)}. A straightforward algorithm is developed for constructing the cubic splines. Finally, this paper includes an experimental validation of the proposed technique by employing a DS1104 dSPACE electronic board along with MATLAB/Simulink software. PMID:23997679

Silva-Ortigoza, R; Mrquez-Snchez, C; Marcelino-Aranda, M; Marciano-Melchor, M; Silva-Ortigoza, G; Bautista-Quintero, R; Ramos-Silvestre, E R; Rivera-Daz, J C; Muoz-Carrillo, D

2013-01-01

121

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

122

Fuel Canister Stress Corrosion Cracking Susceptibility Experimental Results  

SciTech Connect

The National Spent Nuclear Fuel Program is tasked with ensuring the U.S. Department of Energy (DOE)-owned spent nuclear fuel (SNF) is acceptable for permanent disposal at a designated repository. From a repository acceptance criteria viewpoint and from a transportation viewpoint, of significant concern is the condition of the container at the time of shipment. Because the fuel will be in temporary storage for as much as 50 years, verification that no significant degradation has occurred to the canister is required to preclude repackaging all the fuel. Many canisters are also being removed from wet storage, vacuum dried (hot or cold), and then placed into dry storage. This process could have a detrimental effect on canister integrity. Research is currently underway to provide a technically sound assessment of the expected canister condition at the end of interim storage.

Colleen Shelton-Davis

2003-03-01

123

Some Experimental Results with Tree Adjunct Grammar Guided Genetic Programming  

Microsoft Academic Search

Tree-adjunct grammar guided genetic programming (TAG3P) (5) is a grammar guided genetic programming system that uses context-free grammars along with tree-adjunct grammars as means to set language bias for the genetic programming system. In this paper, we show the e xperimental results of TAG3P on two p roblems: symbolic regression and trigonometric identity discovery. The results show that TAG3P works

Nguyen Xuan Hoai; Robert I. Mckay; Daryl Essam

2002-01-01

124

Effects of Imperfect Dynamic Clamp: Computational and Experimental Results  

PubMed Central

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 0.2 ms lead to catastrophic alteration of spike shape, but the frequency-vs.-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.; White, John A.

2008-01-01

125

Development of efficient Laue lenses: experimental results and projects  

NASA Astrophysics Data System (ADS)

Laue lenses are an emerging technology allowing the concentration of soft gamma rays in the ~ 100 keV - 1.5 MeV energy range. Two lens designs based on recently measured crystals are presented in this paper. A lens dedicated to the understanding of the progenitors and explosion physics of Type Ia supernovae through the observation of the 847 keV line produced by the decay chain of the radionuclide 56Co. With a Compton camera at the focus (as proposed for the DUAL mission), we find that a space-borne telescope could reach a 3-? sensitivity of 1.510-6 ph/s/cm2 for a 3% broadened line in 105 s, enabling the detection of several events per year with enough significance to strongly constrain the models. On the other hand, a second generation prototype is proposed. Made to realize a balloon-borne telescope focusing around the electron-positron annihilation line (511 keV), this lens would primarily be a technological demonstrator. However with an estimated sensitivity of 510-6 ph/s/cm2 in 104 s observation time, this Laue lens telescope could bring new hints in the search of the origin of the Galactic positrons. To build this prototype, a dedicated X-ray beamline has been built at the Space Sciences Laboratory.

Barrire, Nicolas; Tomsick, John; Boggs, Steven; Rousselle, Julien; von Ballmoos, Peter

2010-07-01

126

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

127

Theoretical and experimental sunrise mode conversion results at VLF  

Microsoft Academic Search

Previously a mode conversion model was presented which allowed for both the vertical inhomogeneity and anisotropy of the ionosphere. Horizontal inhomogeneity along the direction of propagation was modeled by a slab approximation. The required height gain functions were determined by full-wave solutions and their associated integrals evaluated numerically. In this paper results of a modified mode conversion model are compared

R. A. Pappert; D. G. Morfitt

1975-01-01

128

Cyclone Collection Efficiency: Comparison of Experimental Results with Theoretical Predictions  

Microsoft Academic Search

This paper describes the results of tests conducted on a Stairmand high-efficiency cyclone. The cyclone was pilot-plant scale with a design air flow of 0.139 m\\/s (300 cfm). Collection efficiency and pressure drop were measured over a range of air flows at ambient temperature and pressure. An oil mist was used as a test aerosol because it consisted of spherical

John Dirgo; David Leith

1985-01-01

129

Quark-Gluon Plasma: from lattice simulations to experimental results  

E-print Network

Theoretical studies of quarkonia can elucidate some of the important properties of the quark--gluon plasma, the state of matter realised when the temperature exceeds 150 MeV, currently probed by heavy-ion collisions experiments at BNL and the LHC. We report on our results of lattice studies of bottomonia for temperatures in the range 100 MeV condensed matter physics have proven very successful.

G. Aarts; C. Allton; A. Kelly; J. -I. Skullerud; S. Kim; T. Harris; S. M. Ryan; M. P. Lombardo

2014-03-20

130

Quark-Gluon Plasma: from lattice simulations to experimental results  

E-print Network

Theoretical studies of quarkonia can elucidate some of the important properties of the quark--gluon plasma, the state of matter realised when the temperature exceeds 150 MeV, currently probed by heavy-ion collisions experiments at BNL and the LHC. We report on our results of lattice studies of bottomonia for temperatures in the range 100 MeV condensed matter physics have proven very successful.

Aarts, G; Kelly, A; Skullerud, J -I; Kim, S; Harris, T; Ryan, S M; Lombardo, M P

2014-01-01

131

Experimental Results From a Two-Turn 40-mm Railgun  

Microsoft Academic Search

The Institute for Advanced Technology (IAT) has tested a high-inductance-gradient series-connected two-turn railgun. The primary goal of these experiments was to launch a dual-armature launch package in the two-turn configuration while maintaining electrical isolation between the rail and armature pairs. Two tests with the dual-armature launch package on a single-turn configuration independently examined the performance of the launch package. Results

Trevor Watt; Mark Crawford

2009-01-01

132

Experimental Results From a Two-Turn 40 mm Railgun  

Microsoft Academic Search

The Institute for Advanced Technology (IAT) has tested a high-inductance-gradient series-connected two-turn railgun. The primary goal of these experiments was to launch a dual-armature launch package in the two-turn configuration while maintaining electrical isolation between the rail and armature pairs. Two tests with the dual-armature launch package on a single-turn configuration independently examined the performance of the launch package. Results

Trevor Watt; Mark Crawford

2008-01-01

133

Experimental results of a propeller/wing interaction study  

NASA Technical Reports Server (NTRS)

Steady state measurements have been performed on a propellar and a wing in a tractor configuration, to investigate the consequences of mutual interference on overall performance. For certain geometries wing lift is found to be enhanced, and wing drag to be decreased. The unsteady nature of the propeller-wing aerodynamic interaction has been studied using flow visualization. Results obtained indicate that the tip vortex is severed at the wing leading edge, the severed tip vortex filaments shear in a spanwise direction relative to one another, and these displaced filaments deform to reconnect at the trailing edge.

Johnson, Robert T.; Sullivan, John P.; Witkowski, David P.

1991-01-01

134

Quark-Gluon Plasma: from lattice simulations to experimental results  

NASA Astrophysics Data System (ADS)

Theoretical studies of quarkonia can elucidate some of the important properties of the quark-gluon plasma, the state of matter realised when the temperature exceeds (150) MeV, currently probed by heavy-ion collisions experiments at BNL and the LHC. We report on our results of lattice studies of bottomonia for temperatures in the range 100 MeV lessapprox T lessapprox 450 MeV, introducing and discussing the methodologies we have applied. Of particular interest is the analysis of the spectral functions, where Bayesian methods borrowed and adapted from nuclear and condensed matter physics have proven very successful.

Aarts, G.; Allton, C.; Kelly, A.; Skullerud, J.-I.; Kim, S.; Harris, T.; Ryan, S. M.; Lombardo, M. P.

2014-07-01

135

Parallel and Distributed Computational Fluid Dynamics: Experimental Results and Challenges  

NASA Technical Reports Server (NTRS)

This paper describes several results of parallel and distributed computing using a large scale production flow solver program. A coarse grained parallelization based on clustering of discretization grids combined with partitioning of large grids for load balancing is presented. An assessment is given of its performance on distributed and distributed-shared memory platforms using large scale scientific problems. An experiment with this solver, adapted to a Wide Area Network execution environment is presented. We also give a comparative performance assessment of computation and communication times on both the tightly and loosely-coupled machines.

Djomehri, Mohammad Jahed; Biswas, R.; VanderWijngaart, R.; Yarrow, M.

2000-01-01

136

Mars ionosphere: A review of experimental results and modeling studies  

NASA Astrophysics Data System (ADS)

In this paper we review results from atmospheric and ionospheric experiments on the early planetary missions like the Mariners, Mars, and Viking 1 and 2 Orbiters/Landers. We then discuss the new results obtained from the two latest missions, namely, the Mars Global Surveyor (MGS) and Mars Express (MEX). The MGS had three ionospheric and atmospheric related experiments, namely, (1) the radio science experiment, which generated 5600 electron density profiles covering a major portion of sunspot cycle 23; (2) the magnetometer/electron reflectometer experiment, which very clearly answered the question about the presence or absence of Martian intrinsic magnetic field; and (3) the accelerometer experiment, which provided a large database of atmospheric density at various Martian locations during the aerobraking phases. The topside sounder on the MEX provided electron density profiles for altitudes above the primary ionospheric peak with a very high time resolution, thereby providing opportunity for exploring ionospheric conditions during events of rapid changes like solar flares. Unlike Venus, where simultaneous electron density, ion density, and magnetic field measurements were made, Mars lacks this kind of information. Consequently, most of our current understanding of Mars' plasma environment is based on theoretical models. We therefore review the various atmospheric and ionospheric models for Mars, which have been generated during the last 4 decades.

Haider, S. A.; Mahajan, K. K.; Kallio, E.

2011-10-01

137

Outline Motivation Dimensionality reduction Experimental setup Results Discussion References Dimensionality reduction for supervised learning  

E-print Network

's and Madigan's Experiments with Random Projections for Machine Learning, ACM SIGKDD 2003 #12;Outline Motivation Dimensionality reduction Experimental setup Results Discussion References Outline Motivation Supervised learning reduction Experimental setup Results Discussion References Motivation: supervised learning We obtain a set

Elkan, Charles

138

Microgravity Fluid Separation Physics: Experimental and Analytical Results  

NASA Technical Reports Server (NTRS)

Effective, low power, two-phase separation systems are vital for the cost-effective study and utilization of two-phase flow systems and flow physics of two-phase flows. The study of microgravity flows have the potential to reveal significant insight into the controlling mechanisms for the behavior of flows in both normal and reduced gravity environments. The microgravity environment results in a reduction in gravity induced buoyancy forces acting on the discrete phases. Thus, surface tension, viscous, and inertial forces exert an increased influence on the behavior of the flow as demonstrated by the axisymmetric flow patterns. Several space technology and operations groups have studied the flow behavior in reduced gravity since gas-liquid flows are encountered in several systems such as cabin humidity control, wastewater treatment, thermal management, and Rankine power systems.

Shoemaker, J. Michael; Schrage, Dean S.

1997-01-01

139

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

140

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

141

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

142

Dislocability of Localization Devices for Nonpalpable Breast Lesions: Experimental Results  

PubMed Central

Purpose. For accurate resection of nonpalpable malignant breast lesions with a tumor-free resection rim, an exact and stable wire localization is essential. We tested the resistance towards traction force of different localization devices used in our clinic for breast lesions in two types of tissue. Materials and Methods. Eight different commercially available hook-wire devices were examined for resistance towards traction force using an analogue spring scale. Results. Most systems showed a high level of movement already under small traction force. Retractable systems with round hooks such as the Bard DuaLok , the Fil d'Ariane, and the RPLN Breast Localization Device withstood less traction force than the other systems. However, the Bard DuaLok system was very resistant towards a small traction force of 50?g when compared to the other systems. The Ultrawire Breast Localization Device withstood the most traction force in softer tissue and Kopans Breast Lesion Localization Needle withstood the most force in harder tissue. Conclusion. The Ultrawire Breast Localization Device and Kopans Breast Lesion Localization Needle withstood the most traction force. In general retractable systems withstand less traction force than nonretractable systems. PMID:24724024

Fallenberg, Eva; Diekmann, Felix; Budach, Volker; Maurer, Martin

2014-01-01

143

Experimental aflatoxicosis in swine: morphological and clinical pathological results.  

PubMed Central

The morphological changes in livers of 30 feeder pigs fed diets containing corn contaminated by aflatoxins (0.0 microgram aflatoxins/g feed, 0.4 microgram aflatoxin/g feed, and 0.8 microgram aflatoxin/g feed) were compared with changes in hematology, liver specific serum enzymes, serum proteins, and lymphocyte stimulation indices. Histologically, the livers were classified into five groups. Pigs fed the 0.8 microgram/g diets had the most severe histological lesions of karyomegaly, bile ductule proliferation and hepatocellular degeneration plus elevated gamma-glutamyl transpeptidase, aspartate aminotransferase, and alkaline phosphatase. This group also had significantly lower total protein and albumin values compared to the control pigs. Variation in the severity of the histological lesions was seen in pigs fed 0.4 microgram/g diets as well as variation in lymphocyte indices, liver specific serum enzymes, and electrophoretic results in the affected pigs in that group. Images Fig. 1. Fig. 2. Fig. 3. Fig. 4. Fig. 5. PMID:7337866

Miller, D M; Stuart, B P; Crowell, W A

1981-01-01

144

Some recent experimental results related to nuclear chirality  

NASA Astrophysics Data System (ADS)

Detailed band structures of three chiral-candidate nuclei, 134Pr, 132La and 103Rh have been studied. The aim of the study was twofold. First, to try to explore the reasons behind the contradiction between the theoretically predicted chirality in these nuclei and the recently observed fingerprints that suggest non-chiral interpretation for the previous chiral candidate band doublets. Second, to search for multiple chiral bands of different types in these nuclei. In 134Pr a new ?h11/2vh11/2 band has been observed besides the previously known chiral-candidate ?h11/2vh11/2 doublet. This new band and the yrare ?h11/2vh11/2 band show the expected features of a chiral doublet structure. This fact combined with the observed similarity between the band structures of 134Pr and 132La suggests that chirality might exist in these nuclei. The detailed study of the 103Rh band structure resulted in the observation of two new chiral-doublet looking structures besides the previously known one. This is indicative of possible existence of multiple chiral doublet structure in this nucleus.

Timr, J.; Kuti, I.; Sohler, D.; Starosta, K.; Koike, T.; Paul, E. S.

2014-09-01

145

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

146

Experimental research and analysis of energy efficiency for direct radiant floor heating system with ASHP  

Microsoft Academic Search

This paper presents experimental research and analysis of energy efficiency for direct radiant floor heating system with ASHP (air source heat pump). An experimental platform was built, and the performance of ASHP, heating effect and energy consumption of heating system were studied. The results show that the indoor heat load can be well met when the output capacity of ASHP

Xinling Ma; Xiangrui Meng; Xinli Wei; Zhangchuan Zeng

2011-01-01

147

New experimental sublimation energy measurements for some relevant astrophysical ices  

NASA Astrophysics Data System (ADS)

Context. The knowledge of the sublimation energy of ices allows us to better understand the dynamics between surfaces and atmospheres of different environments of astrophysical interest where ices are present. Aims: This work is intended to provide sublimation energy values for a set of pure ices (CO, CH4, CO2, N2, and NH3) using a new experimental procedure. The results were compared to some values obtained by other authors under different conditions and/or methods, to check the reliability of this new method. Methods: We used the frequency variation obtained from a quartz crystal microbalance to calculate the sublimation energy from the Polany-Wigner equation for the first time. Results: The results obtained are relevant since there are few previous values of sublimation energy reported on these molecules in these conditions of pressure and temperature, which are representative of astrophysical regions. These values are needed in models used to interpret dynamics of icy surfaces. In general, our results compare well to other ones obtained by different methods and complement those previously available.

Luna, R.; Satorre, M. .; Santonja, C.; Domingo, M.

2014-06-01

148

Trends in experimental high-energy physics  

SciTech Connect

Data from a scan of papers in Physical Review Letters and Physical Review are used to demonstrate that American high-energy physicists show a pattern of accelerator and instrumentation usage characteristic of that expected from the logistic-substitution model of Marchetti and of Fischer and Pry.

Sanford, T.W.L.

1982-06-01

149

Short Report Androgens and Energy Allocation: Quasi-Experimental Evidence  

E-print Network

Short Report Androgens and Energy Allocation: Quasi-Experimental Evidence for Effects of Influenza.66 years, SD 5 2.13. Participants were paid US$20. Procedure Two saliva samples were collected at each

Cosmides, Leda

150

Mathematics of complexity in experimental high energy physics  

E-print Network

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.

H. C. Eggers

2005-12-12

151

Experimental assessment of energy saving due to trains regenerative braking in an electrified subway line  

Microsoft Academic Search

The paper deals with research activity conducted in order to determine the impact of regenerative braking techniques adopted on-board trains operating in electrified subway systems. Even though systems adopting this technique are very diffuse worldwide, experimental results demonstrating the impact on energy consumption are rarely made available for the scientific community. The paper reports the results of an extensive experimental

A. Adinolfi; R. Lamedica; C. Modesto; A. Prudenzi; S. Vimercati

1997-01-01

152

A review of thin layer drying of foods: theory, modeling, and experimental results.  

PubMed

Drying is a complicated process with simultaneous heat and mass transfer, and food drying is especially very complex because of the differential structure of products. In practice, a food dryer is considerably more complex than a device that merely removes moisture, and effective models are necessary for process design, optimization, energy integration, and control. Although modeling studies in food drying are important, there is no theoretical model which neither is practical nor can it unify the calculations. Therefore the experimental studies prevent their importance in drying and thin layer drying equations are important tools in mathematical modeling of food drying. They are practical and give sufficiently good results. In this study first, the theory of drying was given briefly. Next, general modeling approaches for food drying were explained. Then, commonly used or newly developed thin layer drying equations were shown, and determination of the appropriate model was explained. Afterwards, effective moisture diffusivity and activation energy calculations were expressed. Finally, experimental studies conducted in the last 10 years were reviewed, tabulated, and discussed. It is expected that this comprehensive study will be beneficial to those involved or interested in modeling, design, optimization, and analysis of food drying. PMID:20373189

Erbay, Zafer; Icier, Filiz

2010-05-01

153

Thermochemical energy storage in inorganic oxides: An experimental evaluation  

Microsoft Academic Search

A thermochemical energy store using CaO (an inorganic oxide) as the storage material has been evaluated. Analysis of the experimental data showed an average deviation of about 17% and accounted for about 8% uncertainties in the primary data. Given the configuration of the rig and the experimental conditions and errors, the experiment has proved that it is feasible to utilise

K. Darkwa

1998-01-01

154

Experimental Comparison of Algorithms for Energy-Efficient Multicasting in Ad Hoc  

E-print Network

instances of the problem and obtain results in terms of the energy efficiency of the solutions obtainedExperimental Comparison of Algorithms for Energy-Efficient Multicasting in Ad Hoc Networks Stavros, Greece Abstract. Energy is a scarce resource in ad hoc wireless networks and it is of paramount

Caragiannis, Ioannis

155

Experimental Research on 0.5 - 10 keV High-Energy Process Resulting from H2 and D2 Ions Flux Interaction with Cathode Solid in Electric Discharge  

Microsoft Academic Search

X-ray emission ranging 0.5 - 10.0 keV with the dose power rate up to 0.01 J\\/s emanating from the cathode solid in the high-current Glow Discharge has been registered in earlier experiments. The X-rays were recorded during the Glow Discharge operation and after the Glow Discharge current switch off. Presumably the observed X-ray emission proceeds as a result of relaxation

A. B. Karabut

156

arXiv:astro-ph/0508014v131Jul2005 A review of experimental results at the knee1  

E-print Network

arXiv:astro-ph/0508014v131Jul2005 A review of experimental results at the knee1 J¨org R. H region of the knee are summarized. The all-particle energy spectrum, the mean logarithmic mass of about 4 PeV, the so called knee. In the literature various reasons for the origin of the knee

157

Experimental and computer simulation results of the spot welding process using SORPAS software  

NASA Astrophysics Data System (ADS)

The highly competitive nature of the automotive industry drives demand for improvements and increased precision engineering in resistance spot welding. Currently there are about 4300 weld points on the average steel vehicle. Current industrial monitoring systems check the quality of the nugget after processing 15 cars, once every two weeks. The nuggets are examined off line using a destructive process, which takes approximately 10 days to complete causing a long delay in the production process. This paper presents a simulation of the spot welding growth curves, along with a comparison to growth curves performed on an industrial spot welding machine. The correlation of experimental results shows that SORPAS simulations can be used as an off line measurement to reduce factory energy usage. The first section in your paper

Al-Jader, M. A.; Cullen, J. D.; Athi, N.; Al-Shamma'a, A. I.

2009-07-01

158

GROUND-COUPLED HEAT-PUMP-SYSTEM EXPERIMENTAL RESULTS* Philip D. Metz  

E-print Network

#12;GROUND-COUPLED HEAT-PUMP-SYSTEM EXPERIMENTAL RESULTS* Philip D. Metz _Solar and Renewables of complete ground coupled heat pump systems (4). Experimental results have been compared to GROCS simulation the cost and feasibility of a residential ground coupled heat pump space conditioning system requiring

Oak Ridge National Laboratory

159

An Experimental Study on Thermal Energy Storage Based Reverse Cycle Defrosting Method Using Subcooling Energy of Refrigerant for Air Source Heat Pump: Characteristics of Thermal Energy Storage Operation  

Microsoft Academic Search

the introduction introduction of the the system of thermal energy storage torage (TES) based reverse cycle defrosting method using sub-cooling energy of refrigerant for air Source heat eat p pump (ASHP) is given firstly. And And then the the characteristic of TES TES using sub-cooling energy of refrigerant in in heating is experimentally researched. The results results show that that

Dong Jiankai; Qu Minglu; Jiang Yiqiang; Yao Yang; Deng Shiming; Wang Honglei

2011-01-01

160

Molecular Dynamics in Ordered Structures: Computer Simulation and Experimental Results for Nylon 66 Crystals  

Microsoft Academic Search

A detailed comparison between molecular dynamics computer simulations and the experimental characterization of molecular motion through deuterium nuclear magnetic resonance (NMR) spectroscopic methods has been carried out for the crystalline phase of nylon 66 (polyhexamethyleneadipamide) at room temperature and just below the melting point. The computer simulations agree quantitatively with the experimental results at room temperature and qualitatively near the

J. J. Wendoloski; K. H. Gardner; J. Hirschinger; H. Miura; A. D. English

1990-01-01

161

Theory versus experimental results and comparisons for five orifice-compensated hybrid bearing configurations  

E-print Network

. Bearing Test Facility D. Experimental Analysis E. Background Hydrostatic Effects Hydrodynamic Effects Hybrid Bearings F. Hydrodynamic Stability Problem UL Literature Review H. Contributions II EXPERIMENTAL RESULTS A. Parameters of Interest B..., 1983) Pressure Generation in a Hydrodynamic Bearing (Vance, 1988), 27 Baseline Bearing Flowrate versus Eccentricity Ratio . . . . . 37 Baseline Bearing Flowrate versus Supply Pressure . . . . . . 38 Baseline Bearing Flowrate versus Running Speed...

Franchek, Nancy Marie

2012-06-07

162

Ply drop-off effects in CFRP\\/honeycomb sandwich panelsexperimental 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

163

Geometric Scaling Effects in Electrical Field Flow Fractionation. 2. Experimental Results  

E-print Network

Geometric Scaling Effects in Electrical Field Flow Fractionation. 2. Experimental Results Bruce K flow fraction- ation (µ-EFFF) systems is investigated experimentally and compared to theory with the miniaturization of biochemical analytical tools for a wide variety of chemical, biological, and pharmaceutical

164

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

165

Electrical properties of molybdenum disulfide MoS 2. Experimental study and density functional calculation results  

Microsoft Academic Search

Molybdenum disulfide is a very interesting material with numerous applications. However, to our knowledge, very few experimental works involving electrical measurements have been performed with this material up to now. This paper is devoted to the characterization of conduction mechanisms in thin layers and pressed pellets. The electronic structure related to the lubricating properties and the activation energy are determined

O. El Beqqali; I. Zorkani; F. Rogemond; H. Chermette; R. Ben Chaabane; M. Gamoudi; G. Guillaud

1997-01-01

166

Turbulence in the stratified atmosphere - Recent theoretical developments and experimental results  

Microsoft Academic Search

Above the boundary layer and outside convective systems, atmospheric turbulence generally occurs within a stably stratified environment. Experimental data clearly reveal that classical ideas about isotropy and inertiality of turbulence may then be questioned. Recent theoretical developments show a wide range of possible turbulent regimes, depending upon different physical hypotheses relating the dominant terms in the momentum and energy balances.

Claude Sidi; Francis Dalaudier

1990-01-01

167

Experimental observation of energy modulation in electron beams passing through terahertz dielectric wakefield structures.  

PubMed

We report the observation of a strong wakefield induced energy modulation in an energy-chirped electron bunch passing through a dielectric-lined waveguide. This modulation can be effectively converted into a spatial modulation forming microbunches with a periodicity of 0.5-1 ps and, hence, capable of driving coherent terahertz radiation. The experimental results agree well with theoretical predictions. PMID:22540797

Antipov, S; Jing, C; Fedurin, M; Gai, W; Kanareykin, A; Kusche, K; Schoessow, P; Yakimenko, V; Zholents, A

2012-04-01

168

Experimental Observation of Energy Modulation in Electron Beams Passing through Terahertz Dielectric Wakefield Structures  

NASA Astrophysics Data System (ADS)

We report the observation of a strong wakefield induced energy modulation in an energy-chirped electron bunch passing through a dielectric-lined waveguide. This modulation can be effectively converted into a spatial modulation forming microbunches with a periodicity of 0.5-1 ps and, hence, capable of driving coherent terahertz radiation. The experimental results agree well with theoretical predictions.

Antipov, S.; Jing, C.; Fedurin, M.; Gai, W.; Kanareykin, A.; Kusche, K.; Schoessow, P.; Yakimenko, V.; Zholents, A.

2012-04-01

169

Experimental Observation of Energy Modulation in Electron Beams Passing Through Terahertz Dielectric Wakefield Structures  

E-print Network

We report observation of a strong wakefield induced energy modulation in an energy-chirped electron bunch passing through a dielectric-lined waveguide. This modulation can be effectively converted into a spatial modulation forming micro-bunches with a periodicity of 0.5 - 1 picosecond, hence capable of driving coherent THz radiation. The experimental results agree well with theoretical predictions.

Antipov, S; Fedurin, M; Gai, W; Kanareykin, A; Kusche, K; Schoessow, P; Yakimenko, V; Zholents, A

2011-01-01

170

Experimental investigation on spectral-energy efficiency of femtosecond laser ablation of metals  

SciTech Connect

Results of investigation on spectral-energy thresholds, rates, and mass flow rates of laser ablation of structural materials (Cu, Ti, Zr, Nb, Mo) of high-energy photonics are presented. The data were obtained by means of an experimental diagnostic module developed for study of multifactor interaction processes between UV-near IR femtosecond laser pulse radiation and condensed media in vacuum.

Loktionov, E. Yu., E-mail: stcpe@bmstu.ru [Bauman Moscow State Technical University (Russian Federation); Ovchinnikov, A. V. [Russian Academy of Sciences, Joint Institute for High Temperatures (Russian Federation); Protasov, Yu. Yu. [Bauman Moscow State Technical University (Russian Federation); Sitnikov, D. S. [Russian Academy of Sciences, Joint Institute for High Temperatures (Russian Federation)

2011-12-15

171

Experimental Studies of Elementary Particle Interactions at High Energies  

SciTech Connect

This is the final report of a program of research on ``Experimental Studies of Elementary Particle Interactions at High Energies'' of the High Energy Physics (HEP) group of The Rockefeller University. The research was carried out using the Collider Detector at Fermilab (CDF) and the Compact Muon Solenoid (CMS) detector at the Large Hadron Collider (LHC) at CERN. Three faculty members, two research associates, and two postdoctoral associates participated in this project. At CDF, we studied proton-antiproton collisions at an energy of 1.96 TeV. We focused on diffractive interactions, in which the colliding antiproton loses a small fraction of its momentum, typically less than 1%, while the proton is excited into a high mass state retaining its quantum numbers. The study of such collisions provides insight into the nature of the diffractive exchange, conventionally referred to as Pomeron exchange. In studies of W and Z production, we found results that point to a QCD-based interpretation of the diffractive exchange, as predicted in a data-driven phenomenology developed within the Rockefeller HEP group. At CMS, we worked on diffraction, supersymmetry (SUSY), dark matter, large extra dimensions, and statistical applications to data analysis projects. In diffraction, we extended our CDF studies to higher energies working on two fronts: measurement of the single/double diffraction and of the rapidity gap cross sections at 7 TeV, and development of a simulation of diffractive processes along the lines of our successful model used at CDF. Working with the PYTHIA8 Monte Carlo simulation authors, we implemented our model as a PYTHIA8-MBR option in PYTHIA8 and used it in our data analysis. Preliminary results indicate good agreement. We searched for SUSY by measuring parameters in the Constrained Minimal Supersymmetric extension of the Standard Model (CMSSM) and found results which, combined with other experimental constraints and theoretical considerations, indicate that the CMSSM is not a viable model. Expressing our results in terms of simple topologies, we exclude squark masses below 0.75 TeV and gluino masses below 1.1 TeV. Astrophysical measurements suggest that about 80% of the matter density of the Universe is non-luminous. One of the theories on dark matter attributes it to Weakly Interacting Massive Particles (WIMPs). We searched for WIMPs in 7 TeV and 8 TeV collisions at CMS and set limits on WIMP production rates, which are competitive and complementary to those of direct detection experiments. Searching for monojets (events with only one jet), which in a popular model could be produced by a jet paired by a gravitino that escapes into extra dimensions, we significantly improved the previously set limit. Our results have been used to set limits on Higgs decay to invisible particles and on production of top squarks in compressed SUSY scenarios. Statistics. We computed Bayesian reference priors for several types of measurement and used them in the analysis of CMS data; investigated the applicability of bootstrap methods to HEP measurements; studied several issues associated with simple-versus-simple hypothesis testing and applied the resulting methods to the measurement of some properties of the top quark and Higgs boson.

Goulianos, Konstantin [The Rockefeller University] [The Rockefeller University

2013-07-31

172

Results from experimental investigations of the performance of air condensers for steam turbine units  

NASA Astrophysics Data System (ADS)

Results from experimental investigations of the model versions of Type ABC GI air condensers are presented, and it is shown that these condensers have better performance characteristics as compared with their analogs that are currently in operation.

Fedorov, V. A.; Mil'man, O. O.; Kolesnikov, N. V.; Anan'ev, P. A.; Dunaev, S. N.; Mikhal'kov, A. M.; Mosin, A. V.; Kondrat'ev, A. V.

2013-02-01

173

Lysosomal dysfunction results in altered energy balance.  

PubMed

The mucopolysaccharidosis (MPS) type VII mouse was originally described as the adipose storage deficiency mouse because of its extreme lean phenotype of unknown etiology. Here, we show that adipose storage deficiency and lower leptin levels are common to five different lysosomal storage diseases (LSDs): MPSI, MPSIIIB, MPSVII, Niemann-Pick type A/B, and infantile neuronal ceroid lipofuscinosis. Elevated circulating pro-inflammatory proteins (VCAM1 and MCP1) were found in multiple LSDs. Multiple anti-inflammatory strategies (dexamethasone, MCP1 deficiency, M3 expression) failed to alter adiposity in LSD animals. All of the models had normal or greater caloric intake and lower to normal metabolic rate, fasting plasma glucose, non-esterified fatty acids, cholesterol, and triglycerides. Triglycerides were lower in the livers of MPSI mice, and the trend was lower in the muscle. Lipid absorption and processing in MPSI mice were indistinguishable from those in normal mice following oral gavage of olive oil. The increased lean mass of MPSI and MPSIIIB mice suggests a shift in adipose triglycerides to lysosomal storage. In agreement, MPSI livers had a similar total caloric content but reduced caloric density, indicating a shift in energy from lipids to proteins/carbohydrates (lysosomal storage). Enzyme replacement therapy normalized the caloric density within 48 h without reducing total caloric content. This was due to an increase in lipids. Recycling of stored material is likely reduced or nonexistent. Therefore, to maintain homeostasis, energy is likely diverted to synthesis at the expense of typical energy storage depots. Thus, these diseases will serve as important tools in studying the role of lysosome function in metabolism and obesity. PMID:17911106

Woloszynek, Josh C; Coleman, Trey; Semenkovich, Clay F; Sands, Mark S

2007-12-01

174

Energy Monitoring--Objectives vs Results  

E-print Network

the "invisible" fluids such as air and natural gas. Savings of $50,000 a year by averting air and gas leaks with in-plant metering have been reported. 5 Accurate metering ~f natural gas has allowed one plant to pay off investment in metering in just five..., Texas, November 1979. 4. Wisch, A. J. And Porter, P. E. "Slashing Steam Use At Carnegie Mellon University," Sixth World Energy Congress, Atlanta, Georgia, 1983. 5. Johnson, R. S., Jr. "Plant Saves $SO,OOO/Year By Averting Air And Gas Leaks...

McEver, R. M. Jr.

175

An experimental characterisation of a Broad Energy Germanium detector  

NASA Astrophysics Data System (ADS)

The spectroscopic and charge collection performance of a BE2825 Broad Energy Germanium (BEGe) detector has been experimentally investigated. The efficiency and energy resolution of the detector have been measured as a function of energy and the noise contributions to the preamplifier signal have been determined. Collimated gamma-ray sources mounted on an automated 3-axis scanning table have been used to study the variation in preamplifier signal shape with gamma-ray interaction position in the detector, so that the position-dependent charge collection process could be characterised. A suite of experimental measurements have also been undertaken to investigate the performance of the detector as a function of bias voltage and we report on anomalous behaviour observed when the detector was operating close to the depletion voltage.

Harkness-Brennan, L. J.; Judson, D. S.; Boston, A. J.; Boston, H. C.; Colosimo, S. J.; Cresswell, J. R.; Nolan, P. J.; Adekola, A. S.; Colaresi, J.; Cocks, J. F. C.; Mueller, W. F.

2014-10-01

176

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

177

Experimental and computational results from a large low-speed centrifugal impeller  

NASA Technical Reports Server (NTRS)

An experimental and computational investigation of the NASA Low-Speed Centrifugal Compressor (LSCC) flow field was conducted using laser anemometry and Dawes' 3D viscous code. The experimental configuration consists of a back-swept impeller followed by a vaneless diffuser. Measurements of the three-dimensional velocity field were acquired at several measurement planes through the compressor. The measurements describe both the throughflow and secondary velocity field along each measurement plane and, in several cases, provide details of the flow within the blade boundary layers. The experimental and computational results provide a clear understanding of the development of the throughflow momentum wake which is characteristic of centrifugal compressors.

Hathaway, M. D.; Chriss, R. M.; Wood, J. R.; Strazisar, A. J.

1994-01-01

178

Experimental and computational results from a large low-speed centrifugal impeller  

NASA Technical Reports Server (NTRS)

An experimental and computational investigation of the NASA Low-Speed Centrifugal Compressor (LSCC) flow field has been conducted using laser anemometry and Dawes' 3D viscous code. The experimental configuration consists of a backswept impeller followed by a vaneless diffuser. Measurements of the three-dimensional velocity field were acquired at several measurement planes through the compressor. The measurements describe both the throughflow and secondary velocity field along each measurement plane and in several cases provide details of the flow within the blade boundary layers. The experimental and computational results provide a clear understanding of the development of the throughflow momentum wake which is characteristic of centrifugal compressors.

Hathaway, M. D.; Chriss, R. M.; Wood, J. R.; Strazisar, A. J.

1993-01-01

179

Cosmic-Ray Spectrum Approximation Model: Experimental Results and Comparison with Other Models  

NASA Astrophysics Data System (ADS)

We discuss a model which parameterizes the cosmic-ray (CR) spectrum at different physical conditions, which include the most important effects controlling the CR intensity, like convection-diffusion and energy losses. By a suitable choice of parameters the proposed model results in two approximations: one close to a "force-field" model (describing the energy losses of CRs in the inner heliosphere) and a "convection-diffusion" equation (giving the reduction of CR intensity in the outer heliosphere). The BESS ( Balloon-borne Experiment with Superconducting Spectrometer) experimental spectra of galactic protons and helium nuclei are fitted by the model spectra. The calculation of the unknown parameters is performed using a constrained least squares method as an alternative to the standard chi-square minimization method, because the data contain not only random errors, but also systematic ones. The CR spectrum approximation (CRSA) model is compared to the Moscow State University (MSU) model and the Badhwar and O'Neill (Badhwar and O'Neill, Adv. Space. Res. 14, 749, 1994; Adv. Space Res. 17, 7, 1994) model; we show that depending on the choice of the model parameters it can be examined in the context of one of these two models. We derive a relation between the parameters of the CRSA and MSU models for rigidities above about 10 GV (drift effects are ignored) during periods of low to approximately average levels of solar activity. The drawbacks of the proposed approximation are that: i) the model parameters do not depend on rigidity and ii) the model does not take into account general trends in the variations of the heliospheric magnetic field; thus, the influence of the drift effects on the shape of the spectral curves for different magnetic field polarity swings is ignored.

Buchvarova, M.; Draganov, D.

2013-06-01

180

Ray matrix for Gaussian beam propagation in a nonlinear medium: experimental results  

NASA Astrophysics Data System (ADS)

The validity of a ray-matrix formulation of Gaussian beam propagation in a liquid nonlinear medium exhibiting self-defocusing is examined experimentally. By comparing the measured spot size of a Gaussian laser beam passing through the medium with the calculated spot size, it was found that the theory is consistent with the experimental results as long as the waist position of the input beam is not close to the exit surface of the medium.

Nemoto, Shojiro

1995-09-01

181

Experimental Results on p(d)+A Collisions at RHIC and the LHC  

E-print Network

Recent experimental results at both the LHC and RHIC show evidence for hydrodynamic behavior in proton-nucleus and deuteron- nucleus collisions (p+A). This unexpected finding has prompted new measurements in p+A collisions in order to understand whether similar matter is created in A+A and p+A collisions or whether some another explanation is needed. In this proceedings, we will discuss the new experimental data and its interpretation within the context of heavy ion collisions.

Anne M. Sickles

2014-08-01

182

The antimicrobial action of high-power electric discharge in water. Part 2. Experimental results  

Microsoft Academic Search

We have experimentally studied the antimicrobial action of high-power pulsed discharge in model solutions, natural water,\\u000a and waste waters inoculated with E. coli 1257 and MS-2 coli-phage species. It is found that the efficiency of the antimicrobial treatment decreases in the presence\\u000a of suspended macroscopic particles. A specific energy consumption of 0.020.04 kW h\\/m3 has been achieved.

K. V. Vilkov; A. L. Grigorev; Yu. A. Nagel; I. V. Uvarova

2004-01-01

183

Experimental results and discussion of imaging with a wire medium for MRI imaging applications  

Microsoft Academic Search

This paper presents an analysis and experimental results for a channeling wire medium. In order to validate the behavior of wire media lens, an experiment has been driven in medical context. A straight wires lens designed to work at magnetic resonance imaging frequency (123 MHZ for 3T magnetic field) is designed and tested. Results are very positive, since the lens

Xavier Radu; Xavier Dardenne; Christophe Craeye

2007-01-01

184

Experimental assessment of energy saving due to trains regenerative braking in an electrified subway line  

Microsoft Academic Search

The paper deals with the research activity conducted in order to determine the impact of regenerative braking techniques adopted on board of trains operating in subway electrified systems. Even though systems adopting this technique are very diffuse world wide, experimental results demonstrating the impact on energy consumption are rarely made available for the scientific community. The paper reports the results

A. Adinolfi; R. Lamedica; C. Modesto; A. Prudenzi; S. Vimercati

1998-01-01

185

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

2002-08-01

186

Interaction of imidazolinone herbicides with soil humic acids. Experimental results and molecular modeling.  

PubMed

Adsorption and desorption isotherms of the herbicides imazapyr, imazethapyr and imazaquin on a soil humic acid have been performed at pH 2.8 and 4.0 (below and above the pKa of the herbicides). At both pH, adsorption increased according to the lipophilic character of the molecules (imazapyr < imazethapyr < imazaquin). The extent of adsorption was higher at pH 2.8 than at pH 4.0 because of the partial ionization of the carboxylic groups of both herbicides and humic acids at increasing pH. Desorption of imazapyr and imazethapyr was nearly complete at pH 4 and higher than 60% at pH 2.8 while desorption of imazaquin was 45 and 8% at pH 4 and 2.8, respectively. No differences between adsorption isotherms at 10 degrees C and 25 degrees C were observed a pH 4.0 indicating that adsorption involved very weak bonds while at pH 2.8, adsorption was higher at 10 degrees C than at 25 degrees C indicating an exothermic process. The isosteric enthalpy of adsorption of each herbicide was low (about -1 kJoule mole(-1)) suggesting that low energetic bonds were involved. Adsorption on different humic acids has indicated that for each herbicide, the extent of adsorption expressed as Kd was correlated with the amount of carboxylic and aromatic groups of humic acids suggesting that hydrogen bonding and/or charge-transfer complexes formation could take place. Molecular modeling and geometry optimization of humic acid and soil organic matter (SOM) herbicide complexes were also performed. The results obtained with this theoretical approach gave a consistent chemical interpretation of the experimental results. To the best of our knowledge this is the first report to contribute to a better understanding of site-specific bonding of herbicides in SOM complexes by nanochemical modeling and distinct energy descriptors. PMID:11409493

Ngre, M; Schulten, H R; Gennari, M; Vindrola, D

2001-03-01

187

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, Jos A; Frins, Erna

2011-07-01

188

Three-dimensional convection in horizontal cylinders - Numerical solutions and comparison with experimental and analytical results  

NASA Technical Reports Server (NTRS)

The results of a three-dimensional numerical simulation of Boussinesq free convection in a horizontal differentially heated cylinder are presented. The computation was based on a Samarskii-Andreyev scheme (described by Leong, 1981) and a false-transient advancement in time, with vorticity, velocity, and temperature as dependent variables. Solutions for velocity and temperature distributions were obtained for Rayleigh numbers (based on the radius) Ra = 74-18,700, thus covering the core- and boundary-layer-driven regimes. Numerical solutions are compared with asymptotic analytical solutions and experimental data. The numerical results well represent the complex three-dimensional flows found experimentally.

Smutek, C.; Bontoux, P.; Roux, B.; Schiroky, G. H.; Hurford, A. C.

1985-01-01

189

Preliminary Experimental Results on Controlled Cardiac Computed Tomography: A Phantom Study  

PubMed Central

In this paper, we present the preliminary experimental results on controlled cardiac computed tomography (CT), which aims to reduce the motion artifacts by means of controlling the x-ray source rotation speed. An innovative cardiac phantom enables us to perform this experiment without modifying the scanner. It is the first experiment on the cardiac CT with speed controlled x-ray source. Experimental results demonstrate that the proposed method successfully separates the phantom images at different phases (improve the temporal resolution) though controlling the x-ray speed. PMID:19696470

Lu, Yang; Cai, Zhijun; Wang, Ge; Zhao, Jun; Bai, Er-Wei

2010-01-01

190

Binding of small basic peptides to membranes containing acidic lipids: theoretical models and experimental results.  

PubMed Central

We measured directly the binding of Lys3, Lys5, and Lys7 to vesicles containing acidic phospholipids. When the vesicles contain 33% acidic lipids and the aqueous solution contains 100 mM monovalent salt, the standard Gibbs free energy for the binding of these peptides is 3, 5, and 7 kcal/mol, respectively. The binding energies decrease as the mol% of acidic lipids in the membrane decreases and/or as the salt concentration increases. Several lines of evidence suggest that these hydrophilic peptides do not penetrate the polar headgroup region of the membrane and that the binding is mainly due to electrostatic interactions. To calculate the binding energies from classical electrostatics, we applied the nonlinear Poisson-Boltzmann equation to atomic models of the phospholipid bilayers and the basic peptides in aqueous solution. The electrostatic free energy of interaction, which arises from both a long-range coulombic attraction between the positively charged peptide and the negatively charged lipid bilayer, and a short-range Born or image charge repulsion, is a minimum when approximately 2.5 A (i.e., one layer of water) exists between the van der Waals surfaces of the peptide and the lipid bilayer. The calculated molar association constants, K, agree well with the measured values: K is typically about 10-fold smaller than the experimental value (i.e., a difference of about 1.5 kcal/mol in the free energy of binding). The predicted dependence of K (or the binding free energies) on the ionic strength of the solution, the mol% of acidic lipids in the membrane, and the number of basic residues in the peptide agree very well with the experimental measurements. These calculations are relevant to the membrane binding of a number of important proteins that contain clusters of basic residues. Images FIGURE 2 FIGURE 3 PMID:8842196

Ben-Tal, N; Honig, B; Peitzsch, R M; Denisov, G; McLaughlin, S

1996-01-01

191

An Experimental and Theoretical High Energy Physics Program  

SciTech Connect

The Purdue High Energy Physics Group conducts research in experimental and theoretical elementary particle physics and experimental high energy astrophysics. Our goals, which we share with high energy physics colleagues around the world, are to understand at the most fundamental level the nature of matter, energy, space and time, and in order to explain the birth, evolution and fate of the Universe. The experiments in which we are currently involved are: CDF, CLEO-c, CMS, LSST, and VERITAS. We have been instrumental in establishing two major in-house facilities: The Purdue Particle Physics Microstructure Detector Facility (P3MD) in 1995 and the CMS Tier-2 center in 2005. The research efforts of the theory group span phenomenological and theoretical aspects of the Standard Model as well as many of its possible extensions. Recent work includes phenomenological consequences of supersymmetric models, string theory and applications of gauge/gravity duality, the cosmological implications of massive gravitons, and the physics of extra dimensions.

Shipsey, Ian

2012-07-31

192

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

193

SINGLE-PROCESS THEORIES OF GRAIN BOUNDARY MIGRATION IN THE LIGHT OF RECENT EXPERIMENTAL RESULTS  

E-print Network

questions which are of general importance for a deeper theoretical understanding of grain boundary migrationSINGLE-PROCESS THEORIES OF GRAIN BOUNDARY MIGRATION IN THE LIGHT OF RECENT EXPERIMENTAL RESULTS F boundary migration requires a knowledge of the atomistic and electronic structure of the grain boundary

Boyer, Edmond

194

Comparison of Computational and Experimental Aerodynamics: Results for a WMU Solar Car Model  

Microsoft Academic Search

Three-dimensional numerical simulations using FLUENT [1] were performed to model the airflow over the Sunseeker, an award-winning solar car that was designed and built at Western Michigan University. Converged numerical solutions on three different grids are reported and compared with the available experimental data, which include the lift and the drag coefficients. Also reported are the results obtained by using

Yang Yang; William W. Liou

2011-01-01

195

Verified Component-based Software in SPARK: Experimental Results for a Missile Guidance System  

E-print Network

Verified Component-based Software in SPARK: Experimental Results for a Missile Guidance System Kung- strate our approach on a missile guidance system. Categories and Subject Descriptors D.2.4 [Software study for a missile guidance system. 2. SOFTWARE COMPONENTS Software components are intended to enable

Lau, Kung-Kiu

196

Distant Speech Recognition for Home Automation: Preliminary Experimental Results in a Smart Home  

E-print Network

Distant Speech Recognition for Home Automation: Preliminary Experimental Results in a Smart Home. The techniques were assessed on real daily living data collected in a 4-room smart home that was fully equipped; triggered language models; home automation; smart home I. INTRODUCTION The evolution of ICT led

Paris-Sud XI, Université de

197

At Odds Reconciling Experimental and Theoretical Results in High School Physics  

Microsoft Academic Search

For this experiment, students are divided into 2 groups and presented with a static equilibrium forcebalance problem to solve. One group works entirely experimentally and the other group theoretically, using Newton's laws. The groups present their seemingly dissimilar results and must reconcile them through discussion.

Joshua Gates

2009-01-01

198

Glancing at Personal Navigation Devices Can Affect Driving: Experimental Results and Design Implications  

E-print Network

Glancing at Personal Navigation Devices Can Affect Driving: Experimental Results and Design. While such devices are less distracting than paper directions, their graphical display may distract users from their primary task of driving. In experiments conducted with a high fidelity driving

New Hampshire, University of

199

Temperature and strain rate influence on AA5086 Forming Limit Curves: experimental results and  

E-print Network

their applications. With innovative warm form- ing methods, the formability of aluminium alloys can be greatly improved. Moreover, under warm forming conditions, the strain rate begins to play a predominant roleTemperature and strain rate influence on AA5086 Forming Limit Curves: experimental results

Boyer, Edmond

200

Genetic and ecological effects of salmon farming on wild salmon: modelling from experimental results  

Microsoft Academic Search

Hindar, K., Fleming, I. A., McGinnity, P., and Diserud, O. 2006. Genetic and ecological effects of salmon farming on wild salmon: modelling from experimental results. ? ICES Journal of Marine Science, 63: 1234e1247. Cultured salmonids are released or escape into the wild in large numbers and may make up significant proportions of wild salmonid populations in fresh- and saltwater, causing

Kjetil Hindar; Ian A. Fleming; Philip McGinnity; Ola Diserud

2006-01-01

201

Theoretical and experimental results of height measurement in a monopulse hard-limited 3D radar  

Microsoft Academic Search

A signal processor that can convert monopulse amplitude data into phase information suitable for a hard-limited receiver was studied. A theoretical estimation of height accuracy was provided (accounting for all errors affecting measurement), and it concurred with results of a Monte Carlo simulation and experimental measurements of calibration flights. It is concluded that the system permits accurate height measurement, good

M. di Lazzaro; G. Fedele; S. Strappaveccia

1983-01-01

202

Modeling and Identification of 2 DOF Low Cost Driving Simulator: Experimental Results  

E-print Network

movements. To enhance the drive immersion in the virtual world, a haptic feedback steering wheel institutions. A driving simulator is virtual reality tool allows users to drive in safe way and test severalModeling and Identification of 2 DOF Low Cost Driving Simulator: Experimental Results Hichem Arioui

Paris-Sud XI, Université de

203

At Odds: Reconciling Experimental and Theoretical Results in High School Physics  

ERIC Educational Resources Information Center

For this experiment, students are divided into 2 groups and presented with a static equilibrium force-balance problem to solve. One group works entirely experimentally and the other group theoretically, using Newton's laws. The groups present their seemingly dissimilar results and must reconcile them through discussion. (Contains 3 figures.)

Gates, Joshua

2009-01-01

204

ANTI-SLUG CONTROL OF GAS-LIFT WELLS -EXPERIMENTAL RESULTS 1  

E-print Network

ANTI-SLUG CONTROL OF GAS-LIFT WELLS - EXPERIMENTAL RESULTS 1 Gisle Otto Eikrem ,2 Ole Morten Aamo and Technology 7491 Trondheim, Norway Abstract: Unstable flow regimes occurring for multiphase flow in gas-lift. In this paper, we employ a nonlinear observer for the states of the multiphase flow in the gas-lift well

Foss, Bjarne A.

205

C Gormezano ENEA Frascati Italy/ MIT presentation 9 February 2001 FTU: Experimental Results and Prospects  

E-print Network

C Gormezano ENEA Frascati Italy/ MIT presentation 9 February 2001 FTU: Experimental Results Frascati #12;C Gormezano ENEA Frascati Italy/ MIT presentation 9 February 2001 FTU Experiment ctd-200keV , 17 chords #12;C Gormezano ENEA Frascati Italy/ MIT presentation 9 February 2001 FTU

206

Geometric and Seabed parameter estimation using a Vector Sensor Array -Experimental results from  

E-print Network

; range and depth source localization. I. INTRODUCTION Acoustic vector sensors emerged in 1980s and dueGeometric and Seabed parameter estimation using a Vector Sensor Array - Experimental results from-139 Faro, Portugal Email: jjoao@yahoo.com Abstract-A vector sensor is constituted by one omni direc tional

Jesus, Sérgio M.

207

Dynamic Friction Models for Longitudinal Road/Tire Interaction: Experimental Results  

E-print Network

Dynamic Friction Models for Longitudinal Road/Tire Interaction: Experimental Results C. Canudas dynamic friction force model for the longitudinal road/tire interaction for wheeled ground vehicles is val- idated via experiments with an actual passenger vehicle. Contrary to common static friction/slip maps

Tsiotras, Panagiotis

208

Experimental and Simulation Performance Results of TCP/IP over High-Speed ATM over ACTS  

E-print Network

Experimental and Simulation Performance Results of TCP/IP over High-Speed ATM over ACTS of future global networks, this paper describes the practical and simulation experiences gained from a TCP/IP Control Protocol/Internet Protocol (TCP/IP) to form an internetwork architecture, has the po- tential

Kansas, University of

209

Abstract--This paper describes experimental results aiming at analyzing lithium-ion batteries performances  

E-print Network

Abstract--This paper describes experimental results aiming at analyzing lithium-ion batteries (SOH) of cells. Index Terms--Lithium-ion batteries, Aging, EIS, State Of Charge, State Of Health, Fuzzy Logic System. I. INTRODUCTION Lithium ion secondary batteries are now being used in wide applications

Boyer, Edmond

210

Adaptive Bolus Chasing Computed Tomography Angiography: Control Scheme and Experimental Results  

E-print Network

Adaptive Bolus Chasing Computed Tomography Angiography: Control Scheme and Experimental Results on bolus-chasing CT angiography using realistic bolus dynamics, real-time CT imaging and adaptive table standard. Keywords Adaptive bolus chasing; Computed Tomography Angiography I. Introduction With the advent

Wang, Ge

211

Experimental Results from a Terrain Adaptive Navigation System for Planetary Rovers  

Microsoft Academic Search

Results from the experimental testing of a navigati on system for planetary rovers called Terrain Adaptive Navigation (TANav) are shown here. This system was designed to enable greater access to and more robus t operations in terrains with widely varying slippage . The system achieves this goal by using onboard ster eo cameras to remotely classify terrain, predict the slippage

Daniel Helmick; Anelia Angelova; Chris Brooks; Ibrahim Halatci

212

Experimental And Theoretical High Energy Physics Research At UCLA  

SciTech Connect

This is the final report of the UCLA High Energy Physics DOE Grant No. DE-FG02- 91ER40662. This report covers the last grant project period, namely the three years beginning January 15, 2010, plus extensions through April 30, 2013. The report describes the broad range of our experimental research spanning direct dark matter detection searches using both liquid xenon (XENON) and liquid argon (DARKSIDE); present (ICARUS) and R&D for future (LBNE) neutrino physics; ultra-high-energy neutrino and cosmic ray detection (ANITA); and the highest-energy accelerator-based physics with the CMS experiment and CERNs Large Hadron Collider. For our theory group, the report describes frontier activities including particle astrophysics and cosmology; neutrino physics; LHC interaction cross section calculations now feasible due to breakthroughs in theoretical techniques; and advances in the formal theory of supergravity.

Cousins, Robert D. [University of California Los Angeles] [University of California Los Angeles

2013-07-22

213

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

214

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

215

Experimental demonstration of thermoacoustic energy conversion in a resonator  

Microsoft Academic Search

Using thermoacoustic energy conversions, both amplification and damping of acoustic intensity are demonstrated. A differentially heated regenerator is installed near the velocity node of the resonator and thereby a high specific acoustic impedance and a traveling wave phase are obtained. It is shown that the gain of acoustic intensity resulting from the traveling wave energy conversion reaches 1.7 in a

Tetsushi Biwa; Yusuke Tashiro; Uichiro Mizutani; Motoki Kozuka; Taichi Yazaki

2004-01-01

216

Design and experimental results for a flapped natural-laminar-flow airfoil for general aviation applications  

NASA Technical Reports Server (NTRS)

A flapped natural laminar flow airfoil for general aviation applications, the NLF(1)-0215F, has been designed and analyzed theoretically and verified experimentally in the Langley Low Turbulence Pressure Tunnel. The basic objective of combining the high maximum lift of the NASA low speed airfoils with the low cruise drag of the NACA 6 series airfoils has been achieved. The safety requirement that the maximum lift coefficient not be significantly affected with transition fixed near the leading edge has also been met. Comparisons of the theoretical and experimental results show generally good agreement.

Somers, D. M.

1981-01-01

217

Experimental Validation of a Novel Compact Focusing Scheme for Future Energy-Frontier Linear Lepton Colliders  

NASA Astrophysics Data System (ADS)

A novel scheme for the focusing of high-energy leptons in future linear colliders was proposed in 2001 [P. Raimondi and A. Seryi, Phys. Rev. Lett. 86, 3779 (2001)]. This scheme has many advantageous properties over previously studied focusing schemes, including being significantly shorter for a given energy and having a significantly better energy bandwidth. Experimental results from the ATF2 accelerator at KEK are presented that validate the operating principle of such a scheme by demonstrating the demagnification of a 1.3 GeV electron beam down to below 65 nm in height using an energy-scaled version of the compact focusing optics designed for the ILC collider.

White, G. R.; Ainsworth, R.; Akagi, T.; Alabau-Gonzalvo, J.; Angal-Kalinin, D.; Araki, S.; Aryshev, A.; Bai, S.; Bambade, P.; Bett, D. R.; Blair, G.; Blanch, C.; Blanco, O.; Blaskovic-Kraljevic, N.; Bolzon, B.; Boogert, S.; Burrows, P. N.; Christian, G.; Corner, L.; Davis, M. R.; Faus-Golfe, A.; Fukuda, M.; Gao, J.; Garca-Morales, H.; Geffroy, N.; Hayano, H.; Heo, A. Y.; Hildreth, M.; Honda, Y.; Huang, J. Y.; Hwang, W. H.; Iwashita, Y.; Jang, S.; Jeremie, A.; Kamiya, Y.; Karataev, P.; Kim, E. S.; Kim, H. S.; Kim, S. H.; Kim, Y. I.; Komamiya, S.; Kubo, K.; Kume, T.; Kuroda, S.; Lam, B.; Lekomtsev, K.; Liu, S.; Lyapin, A.; Marin, E.; Masuzawa, M.; McCormick, D.; Naito, T.; Nelson, J.; Nevay, L. J.; Okugi, T.; Omori, T.; Oroku, M.; Park, H.; Park, Y. J.; Perry, C.; Pfingstner, J.; Phinney, N.; Rawankar, A.; Renier, Y.; Resta-Lpez, J.; Ross, M.; Sanuki, T.; Schulte, D.; Seryi, A.; Shevelev, M.; Shimizu, H.; Snuverink, J.; Spencer, C.; Suehara, T.; Sugahara, R.; Takahashi, T.; Tanaka, R.; Tauchi, T.; Terunuma, N.; Toms, R.; Urakawa, J.; Wang, D.; Warden, M.; Wendt, M.; Wolski, A.; Woodley, M.; Yamaguchi, Y.; Yamanaka, T.; Yan, J.; Yokoya, K.; Zimmermann, F.; ATF2 Collaboration

2014-01-01

218

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

NASA Technical Reports Server (NTRS)

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.

1992-01-01

219

Modeling the Fracturing of Rock by Fluid Injection - Comparison of Numerical and Experimental Results  

NASA Astrophysics Data System (ADS)

Fluid-rock interactions are mechanically fundamental to many earth processes, including fault zones and hydrothermal/volcanic systems, and to future green energy solutions such as enhanced geothermal systems and carbon capture and storage (CCS). Modeling these processes is challenging because of the strong coupling between rock fracture evolution and the consequent large changes in the hydraulic properties of the system. In this talk, we present results of a numerical model that includes poro-elastic plastic rheology (with hardening, softening, and damage), and coupled to a non-linear diffusion model for fluid pressure propagation and two-phase fluid flow. Our plane strain model is based on the poro- elastic plastic behavior of porous rock and is advanced with hardening, softening and damage using the Mohr- Coulomb failure criteria. The effective stress model of Biot (1944) is used for coupling the pore pressure and the rock behavior. Frictional hardening and cohesion softening are introduced following Vermeer and de Borst (1984) with the angle of internal friction and the cohesion as functions of the principal strain rates. The scalar damage coefficient is assumed to be a linear function of the hardening parameter. Fluid injection is modeled as a two phase mixture of water and air using the Richards equation. The theoretical model is solved using finite differences on a staggered grid. The model is benchmarked with experiments on the laboratory scale in which fluid is injected from below in a critically-stressed, dry sandstone (Stanchits et al. 2011). We simulate three experiments, a) the failure a dry specimen due to biaxial compressive loading, b) the propagation a of low pressure fluid front induced from the bottom in a critically stressed specimen, and c) the failure of a critically stressed specimen due to a high pressure fluid intrusion. Comparison of model results with the fluid injection experiments shows that the model captures most of the experimental observations, including fracture evolution, excellent agreement of the entire load-unload stress strain behavior, and applicable to both drained and un-drained conditions. Bibliography: M.A. Biot. General Theory of Three- Dimensional Consolidation. Journal of Applied Physics, 12:155 - 164, February 1941. P.A. Vermeer and R. de Borst. Non- associated Plasticity For Soils, Concrete and Rock. Heron, 29(37), 1984. S. Stanchits, S. Mayr, S. Shapiro and G. Dresen. Fracturing of Porous Rock Induced by Fluid Injection. Tectonophysics, (503):129-145, 2011.

Heinze, Thomas; Galvan, Boris; Miller, Stephen

2013-04-01

220

Experimental temperature measurements for the energy amplifier test  

NASA Astrophysics Data System (ADS)

A uranium thermometer has been designed and built in order to make local power measurements in the First Energy Amplifier Test (FEAT). Due to the experimental conditions power measurements of tens to hundreds of nW were required, implying a sensitivity in the temperature change measurements of the order of 1 mK. A uranium thermometer accurate enough to match that sensitivity has been built. The thermometer is able to determine the absolute energetic gain obtained in a tiny subcritical uranium assembly exposed to a proton beam of kinetic energies between 600 MeV and 2.75 GeV. In addition, the thermometer measurements have provided information about the spatial power distribution and the shape of the neutron spallation cascade.

Calero, J.; Cennini, P.; Gallego, E.; Glvez, J.; Tabares, L. Garca; Gonzlez, E.; Jaren, J.; Lpez, C.; Lorente, A.; Val, J. M. Martnez; Oropesa, J.; Rubbia, C.; Rubio, J. A.; Saldaa, F.; Tamarit, J.; Vieira, S.

1996-02-01

221

Motivations PSO Aided OFR Based RBF Classifier Experimental Results Conclusions Radial Basis Function Classifier Construction Using Particle  

E-print Network

Modelling PSO Aided OFR Algorithm 3 Experimental Results Breast Cancer Data Diabetes Data Thyroid Data 4 Aided OFR Algorithm 3 Experimental Results Breast Cancer Data Diabetes Data Thyroid Data 4 Conclusions Aided OFR Algorithm 3 Experimental Results Breast Cancer Data Diabetes Data Thyroid Data 4 Conclusions

Chen, Sheng

222

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

223

A liquid Xenon Positron Emission Tomograph for small animal imaging : first experimental results of a prototype cell  

E-print Network

A detector using liquid Xenon (LXe) in the scintillation mode is studied for Positron Emission Tomography (PET) of small animals. Its specific design aims at taking full advantage of the Liquid Xenon scintillation properties. This paper reports on energy, time and spatial resolution capabilities of the first LXe prototype module equipped with a Position Sensitive Photo- Multiplier tube (PSPMT) operating in the VUV range (178 nm) and at 165 K. The experimental results show that such a LXe PET configuration might be a promising solution insensitive to any parallax effect.

Gallin-Martel, M L; Grondin, Y; Rossetto, O; Collot, J; Grondin, D; Jan, S; Martin, Ph; Mayet, F; Petit, P; Vezzu, F

2008-01-01

224

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 Flgge et al. (1972). PMID:21890370

Gonzales, D; Requena, S; Williams, S

2012-01-01

225

Experimental assessment of energy saving due to trains regenerative braking in an electrified subway line  

SciTech Connect

The paper deals with the research activity conducted in order to determine the impact of regenerative braking techniques adopted on board of trains operating in subway electrified systems. Even though systems adopting this technique are very diffuse world wide, experimental results demonstrating the impact on energy consumption are rarely made available for the scientific community. The paper reports the results of an extensive experimental activity conducted on an electrified subway line in Rome, in order to estimate the energy saving due to the techniques above mentioned. Since the monitoring activity of the system demand in absence of regenerative braking had to be limited to the traffic peak hours of only two subsequent days, an available model, being able to simulate the instantaneous demand profile of DC electrified subway power systems, has been used in order to extend the numerical evaluations based on the experimental activity to a whole day of operation.

Adinolfi, A. [Intermetro S.p.A. (Italy)] [Intermetro S.p.A. (Italy); Lamedica, R.; Modesto, C.; Prudenzi, A. [Univ. of Rome La Sapienza (Italy)] [Univ. of Rome La Sapienza (Italy); Vimercati, S. [Transystem S.p.A. (Italy)] [Transystem S.p.A. (Italy)

1998-10-01

226

A comment on experimental results of fingerprint comparison validity and reliability: A review and critical analysis.  

PubMed

We respond to the article "Experimental results of fingerprint comparison validity and reliability: A review and critical analysis" by Ralph and Lyn Haber which offers (a) a one-sided criticism of the state of affairs in latent print examination, (b) lack of original data supporting that their suggested approach, and (c) a host of incorrect statements, inaccuracies, or obscure interpretations of the existing data. PMID:25278205

Langenburg, Glenn; Neumann, Cedric; Champod, Christophe

2014-09-01

227

A scattering and absorption identity for metamaterials experimental results and comparison with theory  

Microsoft Academic Search

Abstract 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 summation,rule by measuring,the

Christian Sohl; Christer Larsson; Mats Gustafsson; Gerhard Kristensson

2007-01-01

228

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

229

Selective water sorbent for solid sorption chiller: experimental results and modelling  

Microsoft Academic Search

In this paper the experimental results of a lab-scale chilling module working with the composite sorbent SWS-1L (mesoporous silica gel impregnated with CaCl2) are presented. The interesting sorption properties of this material yield a high COP=0.6 that gives a promising alternative to the common zeolite or silica gel for application in solid sorption units driven by low temperature heat (T

G. Restuccia; A. Freni; S. Vasta; Yu Aristov

2004-01-01

230

Dynamic soil-structure interaction-comparison of FEM model with experimental results  

E-print Network

with my research at various times. Luben Todorovski helped me with his data sets and explained his experimental study. His help is greatly appreciated. Samuel Young-Gameros and Anil Ayalasomayajula helped me immensely with ABAQUS and PATRAN. I am very.... . . III THE FINITE ELEMENT MODEL. . . . . 13 17 22 ABAQUS . . Finite Element Method. . The Input File. The Finite Element Mesh. . Loads and Boundary Conditions. . . Analysis. 25 25 26 27 30 33 The Models. Page . 34 IV RESULTS. 36...

Srinivasan, Palanivel Rajan

2012-06-07

231

Recent Results from Gamma-Ray Energy Tracking Array GRETINA  

NASA Astrophysics Data System (ADS)

The gamma-ray energy tracking array GRETINA uses 28 Ge crystals, each with 36 segments, to cover .5ex1 -.1em/ -.15em.25ex4 of the 4? solid angle. The gamma ray tracking technique uses detailed pulse shape information from each of the segments. These pulses are analyzed to determine the energy, time, and three-dimensional positions of all gamma-ray interactions. This information is then utilized, together with the characteristics of Compton scattering and pair-production processes, to track the scattering sequences of the gamma rays. Tracking arrays will give higher efficiency, better peak-to-total ratio and much higher position resolution, and thus increases the detection sensitivity by factors of several hundred compared to current arrays used in nuclear physics research. Particularly, for fast beam experiments tracking will provide spectra quality comparable to that from a Compton suppressed array, such as Gammasphere, while having the position resolution needed for the accurate Doppler correction comparable to detectors designed for good position resolution such as SeGA. GRETINA construction at the 88-Inch Cyclotron at LBNL was completed in March 2011. Extensive engineering and commissioning runs were carried out using radioactive sources, and beams from the Cyclotron until March 2012. The data obtained have been used to debug and improve its performance. After the commissioning period, GRETINA was moved to NSCL MSU and installed at the target position of the S800 spectrograph. The experimental program with a total of twenty four experiments will start in July 2012 after successful commissioning runs. I will present preliminary results from these runs and discuss future research plans.

Lee, I.-Yang

2012-10-01

232

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)] [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)] [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)] [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)] [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)] [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)] [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)] [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)] [National Institute for Physics and Nuclear Engineering, RO-76900 Bucharest-Magurele (Romania); Rosato, E. [Dipartimento di Scienze Fisiche, Univ. di Napoli, 180126 Napoli (Italy)] [Dipartimento di Scienze Fisiche, Univ. di Napoli, 180126 Napoli (Italy); Gourio, D. [Gesellschaft fuer Schwerionenforschung, D-64291 Darmstadt (Germany)] [Gesellschaft fuer Schwerionenforschung, D-64291 Darmstadt (Germany); Majka, Z. [Institute of Physics, Jagellonian University ul. Roeymonta 4, 30-059 Krakow (Poland)] [Institute of Physics, Jagellonian University ul. Roeymonta 4, 30-059 Krakow (Poland)

1998-07-01

233

Experimental demonstration of thermoacoustic energy conversion in a resonator.  

PubMed

Using thermoacoustic energy conversions, both amplification and damping of acoustic intensity are demonstrated. A differentially heated regenerator is installed near the velocity node of the resonator and thereby a high specific acoustic impedance and a traveling wave phase are obtained. It is shown that the gain of acoustic intensity resulting from the traveling wave energy conversion reaches 1.7 in a positive temperature gradient and 0.3 in a negative gradient. When the regenerator is replaced with a stack, it is found that the gain reaches 2.3, exceeding the temperature ratio (=1.9) of both ends of the stack. This is brought about by the addition of standing wave energy conversion. The present results would contribute to the development of new acoustic devices using thermoacoustic energy conversion. PMID:15244723

Biwa, Tetsushi; Tashiro, Yusuke; Mizutani, Uichiro; Kozuka, Motoki; Yazaki, Taichi

2004-06-01

234

Experimental studies of pion-nucleus interactions at intermediate energies  

SciTech Connect

This report summarizes the work on experimental research in intermediate energy nuclear physics carried out at New Mexico State University in 1991 under a great from the US Department of Energy. Most of these studies have involved investigations of various pion-nucleus interactions. The work has been carried out both with the LAMPF accelerator at the Los Alamos National Laboratory and with the cyclotron at the Paul Scherrer Institute (PSI) near Zurich, Switzerland. Part of the experimental work involves measurements of new data on double-charge-exchange scattering, using facilities at LAMPF which we helped modify, and on pion absorption, using a new detector system at PSI that covers nearly the full solid-angle region which we helped construct. Other work involved preparation for future experiments using polarized nuclear targets and a new high-resolution spectrometer system for detecting {pi}{sup 0} mesons. We also presented several proposals for works to be done in future years, involving studies related to pi-mesonic atoms, fundamental pion-nucleon interactions, studies of the difference between charged and neutral pion interactions with the nucleon, studies of the isospin structure of pion-nucleus interactions, and pion scattering from polarized {sup 3}He targets. This work is aimed at improving our understanding of the pion-nucleon interaction, of the pion-nucleus interaction mechanism, and of nuclear structure.

Not Available

1991-12-31

235

Simulation and preliminary experimental results for an active neutron counter using a neutron generator for a fissile material accounting  

NASA Astrophysics Data System (ADS)

An active neutron coincidence counter using a neutron generator as an interrogation source has been suggested. Because of the high energy of the interrogation neutron source, 2.5 MeV, the induced fission rate is strongly affected by the moderator design. MCNPX simulation has been performed to evaluate the performance achieved with these moderators. The side- and bottom-moderator are significantly important to thermalize neutrons to induce fission. Based on the simulation results, the moderators are designed to be adapted to the experimental system. Their preliminary performance has been tested by using natural uranium oxide powder samples. For a sample of up to 3.5 kg, which contains 21.7 g of 235U, 2.64 cps/g- 235U coincidence events have been measured. Mean background error was 9.57 cps and the resultant coincidence error was 13.8 cps. The experimental result shows the current status of an active counting using a neutron generator which still has some challenges to overcome. However, the controllability of an interrogation source makes this system more applicable for a variety of combinations with other non-destructive methods like a passive coincidence counting especially under a harsh environment such as a hot cell. More precise experimental setup and tests with higher enriched samples will be followed to develop a system to apply it to an active measurement for the safeguards of a spent fuel treatment process.

Ahn, Seong-Kyu; Lee, Tae-Hoon; Shin, Hee-Sung; Kim, Ho-Dong

2009-10-01

236

Experimental Testing and Model Validation for Ocean Wave Energy Harvesting Buoys  

E-print Network

Experimental Testing and Model Validation for Ocean Wave Energy Harvesting Buoys Douglas A. Gemme1 are presented for numerical simulations and field experiments using point absorption ocean wave energy and experimental data. Index Terms ­ energy conversion, wave energy harvesting, linear generator, ocean energy

Grilli, Stéphan T.

237

Experimental limit on low energy antiprotons in the cosmic radiation  

NASA Technical Reports Server (NTRS)

Results are reported from the Low Energy Antiproton Experiment (LEAP), a balloon-borne instrument which was flown in August, 1987. No evidence of antiproton fluxes is found in the kinetic energy range of 120 MeV to 360 MeV, at the top of the atmosphere. The 90-percent is found confidence upper limit on the antiproton/proton ratio in this energy range is 3.5 x 10 to the -5th. In particular, this new experiment places an upper limit on the flux almost an order of magnitude below the reported flux of Buffington et al. (1981).

Streitmatter, R. E.; Stochaj, S. J.; Ormes, J. F.; Golden, R. L.; Stephens, S. A.

1989-01-01

238

Low Energy Solar Neutrino Spectroscopy:. Results from the Borexino Experiment  

NASA Astrophysics Data System (ADS)

Till very recent the real-time solar neutrino experiments were detecting the tiny fraction of about 0.01% of the total neutrino flux above some MeV energy, the sub-MeV region remained explored only by radiochemical experiments without spectroscopical capabilities. The Borexino experiment, an unsegmented large volume liquid scintillator detector located in the Gran Sasso National Laboratory in central Italy, is at present the only experiment in the world acquiring the real-time solar neutrino data in the low-energy region, via the elastic scattering on electrons in the target mass. The data taking campaign started in 2007 and rapidly lead to the first independent measurement of the mono-cromatic line of 7Be of the solar neutrino spectrum at 862keV, which is of special interest because of the very loose limits coming from existing experiments. The latest measurement, after 41.3t yr of exposure, is (49 3stat 4syst)c/(day 100t) and leaves the hypothesis of no oscillation inconsistent with data at 4? level. It also represents the first direct measurement of the survival probability for solar ? e (P{7 Be}ee = 0.56 0.10) in the vacuum-dominates oscillation regime. Recently Borexino was also able to measure of the 8B solar neutrinos interaction rate down to the threshold energy of 3 MeV, the lowest achieved so far. The inferred electron neutrino flux is ? {8 B}ES = (2.7 0.4stat 0.1syst ) 106 cm{ - 2} s{ - 1} . The corresponding mean electron neutrino survival probability, is P{8 B}ee = 0.29 0.10 at the effective energy of 8.9 MeV. Both measurements are in good agreement with other existing measurements and with predictions from the SSM in the hypothesis of MSW-LMA oscillation scenario. For the first time, thanks to the unprecedented radio-purity of the Borexino target and construction materials, we confirm with a single detector, the presence of a transition between the low energy vacuum-dominated and the high-energy matter-enhanced solar neutrino oscillations. A further confirmations of the LMA scenario is provided by the absence of a day-night asymmetry in the 7Be signal. These experimental results allow to improve the knowledge of the pp neutrino flux, to place an upper limit on the CNO flux and also to explore non standard neutrino properties, improving the upper limit on the neutrino effective magnetic moment. Calibration campaigns aiming to reduce the systematical errors on fiducial volume definition and detector energy response have been performed and data analysis is presently in progress. Borexino has also recently observed antineutrinos from the Earth, for the first time at more the 3? C.L. and has measured a rate of 3.9{ - 1.3}{ + 1.6} <=ft( {{ - 3.2}{ + 5.8} } ; ) events/(100ton-yr) at 68.3%(99.73%) C.L. Borexino is also a powerful supernova neutrino detector. Future prospects of the experiment include reducing the systematic error on the 7Be flux to below 5% and direct measurement of additional solar neutrino emissions such as pep, CNO and possibly pp.

D'Angelo, D.

2011-03-01

239

Aerosol bolus dispersion in healthy and asthmatic children--theoretical and experimental results  

PubMed Central

Introduction In the past decades, aerosol bolus inhalation increasingly came into the focus of medical interest due to its potential as a non-invasive technique for the diagnosis of lung diseases. The experimental studies were accompanied by the development of theoretical contributions dealing with aerosol bolus behaviour in healthy and diseased lungs. In this study, bolus dispersion in healthy and asthmatic children is subject to a theoretical approach. Model predictions are validated with related experimental findings. Methods Aerosol bolus transport was simulated by using (I) a stochastic model of the human respiratory tract; (II) appropriate scaling procedures for the generation of healthy and asthmatic lungs of children; and (III) the concept of effective diffusivities (Deff) for the prediction of convective mixing processes in the conducting airways and alveoli. The aerosol injected into the inhalative air stream consisted of monodisperse particles with a diameter of 0.4 m (? =1 g?cm3). Volumetric lung depth, being a measure for the position of the aerosol bolus within the inspired air stream, was varied from 95 mL (shallow bolus) to 540 mL (deep bolus). Half-width of the inhaled bolus was set to 50 mL. Results According to the predictions provided by the model, dispersion of the exhaled aerosol bolus increases exponentially with volumetric lung depth in both asthmatic children and healthy controls. Asthmatics tend to develop higher bolus dispersion than healthy subjects, with significant differences between the two groups being noticeable at low volumetric lung depths (<300 mL). Skewness decreases with increasing volumetric lung depth, whereby respective values calculated for asthmatics exceed those values computed for healthy subjects. Theoretical results correspond very well with experimental findings. Discussion and conclusions Results of experimental bolus studies may be approximated by theoretical models with high accuracy. Model predictions confirm the assumption that inhalation of aerosol boluses and dispersion measurements have only a limited diagnostic potential.

2014-01-01

240

Experimental investigation of energy balance in plasma arc cutting process  

NASA Astrophysics Data System (ADS)

The present paper describes the power balance of the arc cutting process provided by a plasma torch with steam working medium. The work was concentrated on definition of different power terms including power input as well as effective power utilization and losses as a function of plasma gas flow rate. The work was mostly experimental. The results have shown around 20% of total available power is utilized for material cutting and removing for the studied conditions.

Kavka, T.; Tossen, S.; Maslani, A.; Konrad, M.; Pauser, H.; Stehrer, T.

2014-05-01

241

Artificial cochlea and acoustic black hole travelling waves observation: Model and experimental results  

NASA Astrophysics Data System (ADS)

An inhomogeneous fluid structure waveguide reproducing passive behaviour of the inner ear is modelled with the help of the Wentzel-Kramers-Brillouin method. A physical setup is designed and built. Experimental results are compared with a good correlation to theoretical ones. The experimental setup is a varying width plate immersed in fluid and terminated with an acoustic black hole. The varying width plate provides a spatial repartition of the vibration depending on the excitation frequency. The acoustic black hole is made by decreasing the plate's thickness with a quadratic profile and by covering this region with a thin film of viscoelastic material. Such a termination attenuates the flexural wave reflection at the end of the waveguide, turning standing waves into travelling waves.

Foucaud, Simon; Michon, Guilhem; Gourinat, Yves; Pelat, Adrien; Gautier, Franois

2014-07-01

242

Shuttle Return To Flight Experimental Results: Cavity Effects on Boundary Layer Transition  

NASA Technical Reports Server (NTRS)

The effect of an isolated rectangular cavity on hypersonic boundary layer transition of the windward surface of the Shuttle Orbiter has been experimentally examined in the Langley Aerothermodynamics Laboratory in support of an agency-wide effort to prepare the Shuttle Orbiter for return to flight. This experimental study was initiated to provide a cavity effects database for developing hypersonic transition criteria to support on-orbit decisions to repair a damaged thermal protection system. Boundary layer transition results were obtained using 0.0075-scale Orbiter models with simulated tile damage (rectangular cavities) of varying length, width, and depth. The database contained within this report will be used to formulate cavity-induced transition correlations using predicted boundary layer edge parameters.

Liechty, Derek S.; Horvath, Thomas J.; Berry, Scott A.

2006-01-01

243

Shuttle Return To Flight Experimental Results: Protuberance Effects on Boundary Layer Transition  

NASA Technical Reports Server (NTRS)

The effect of isolated roughness elements on the windward boundary layer of the Shuttle Orbiter has been experimentally examined in the Langley Aerothermodynamic Laboratory in support of an agency-wide effort to prepare the Shuttle Orbiter for return to flight. This experimental effort was initiated to provide a roughness effects database for developing transition criteria to support on-orbit decisions to repair damage to the thermal protection system. Boundary layer transition results were obtained using trips of varying heights and locations along the centerline and attachment lines of 0.0075-scale models. Global heat transfer images using phosphor thermography of the Orbiter windward surface and the corresponding heating distributions were used to infer the state of the boundary layer (laminar, transitional, or turbulent). The database contained within this report will be used to formulate protuberance-induced transition correlations using predicted boundary layer edge parameters.

Liechty, Derek S.; Berry, Scott A.; Horvath, Thomas J.

2006-01-01

244

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

245

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

246

Supersonic Retropropulsion Experimental Results from the NASA Ames 9- x 7-Foot Supersonic Wind Tunnel  

NASA Technical Reports Server (NTRS)

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 Mach 2.4, 3.5 and 4.6, was a 5-in diameter 70-deg sphere-cone forebody with a 9.55-in long cylindrical aftbody. The forebody was designed to accommodate up to four 4:1 area ratio nozzles, one on the model centerline and the other three on the half radius spaced 120-deg apart. Surface pressure and flow visualization were the primary measurements, including high-speed data to investigate the dynamics of the interactions between the bow and nozzle shocks. Three blowing configurations were tested with thrust coefficients up to 10 and angles of attack up to 20-deg. Preliminary results and observations from the test are provided

Berry, Scott A.; Rhode, Matthew N.; Edquist, Karl T.

2012-01-01

247

Wave spectra of a shoaling wave field: A comparison of experimental and simulated results  

NASA Technical Reports Server (NTRS)

Wave profile measurements made from an aircraft crossing the North Carolina continental shelf after passage of Tropical Storm Amy in 1975 are used to compute a series of wave energy spectra for comparison with simulated spectra. Results indicate that the observed wave field experiences refraction and shoaling effects causing statistically significant changes in the spectral density levels. A modeling technique is used to simulate the spectral density levels. Total energy levels of the simulated spectra are within 20 percent of those of the observed wave field. The results represent a successful attempt to theoretically simulate, at oceanic scales, the decay of a wave field which contains significant wave energies from deepwater through shoaling conditions.

Morris, W. D.; Grosch, C. E.; Poole, L. R.

1982-01-01

248

Beta decay and the origin of biologial chirality - New experimental results  

NASA Technical Reports Server (NTRS)

The hypothetical connection developed by Vester and Ulbricht (1959), between the handedness of beta particles in radioactive decay and the (L) sign of biologial chirality is investigated in a radiolysis experiment. The experiment measured the predicted asymmetry in the formation triplet or 'ortho-' positronium (oPs) in amino acid enantiomers by low energy positrons under conditions of helicity reversal. The positrons were focused on amino acid powder samples. By measuring the time between positron arrival and emission of gamma rays, long-lived oPs were separated from other species. It is found that the asymmetry in leucine (0.8 x 10 to the -4th) is consistent with the theoretical prediction of 10 to the -6th. Neither the experimental limits nor the theoretical estimates are found to rule out a mechanism like that described by Vester and Ulbricht as the cause of the sign of the observed chiral polarization.

Van House, J.; Rich, A.; Zitzewitz, P. W.

1984-01-01

249

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

250

Investigation of superelastic electron scattering by laser-excited Ba - Experimental procedures and results  

NASA Technical Reports Server (NTRS)

Differential (in angle) electron scattering experiments on laser-excited Ba-138 1P were carried out at 30- and 100-eV impact energies. The laser light was linearly polarized and located in the scattering plane. The superelastic scattering signal was measured as a function of polarization direction of the laser light with respect to the scattering plane. It was found at low electron scattering angles that the superelastic scattering signal was asymmetric to reflection of the polarization vector with respect to the scattering plane. This is in contradiction with theoretical predictions. An attempt was made to pinpoint the reason for this observation, and a detailed investigation of the influence of experimental conditions on the superelastic scattering was undertaken. No explanation for the asymmetry has as yet been found.

Register, D. F.; Trajmar, S.; Fineman, M. A.; Poe, R. T.; Csanak, G.; Jensen, S. W.

1983-01-01

251

Turbulence in the stratified atmosphere - Recent theoretical developments and experimental results  

NASA Astrophysics Data System (ADS)

Above the boundary layer and outside convective systems, atmospheric turbulence generally occurs within a stably stratified environment. Experimental data clearly reveal that classical ideas about isotropy and inertiality of turbulence may then be questioned. Recent theoretical developments show a wide range of possible turbulent regimes, depending upon different physical hypotheses relating the dominant terms in the momentum and energy balances. The scaling of stratified turbulence proposed by (A.E. Gargett) will be extensively reviewed, such as present views of the turbulent buoyancy subrange. Key measurements appear to be those of temperature, vertical and horizontal velocites along vertical paths and, most of all, estimations of vertical heat flux (or mass flux) spectra. Recent atmospheric measurements acquired by balloon borne instrumentation in the upper troposphere and lower stratosphere will be presented as they give some insight in these debates. Owing to its great practical importance, the problem of the relationships between temperature and velocities fluctuations will be specifically discussed.

Sidi, Claude; Dalaudier, Francis

252

Experimental Studies of Few-nucleon Systems at Intermediate Energies  

NASA Astrophysics Data System (ADS)

Systems composed of 3 nucleons are a subject of precise experimental studies for many years. At the first stage the investigations were mainly focused on elastic nucleon-deuteron scattering, slowly extending to systematic measurements of the deuteron breakup reaction. Intermediate energies, below the threshold for pion production, deserve special attention: it is the region where comparison with exact theoretical calculations is possible, while the sensitivity to various aspects of interaction, like subtle effects of the dynamics beyond the pairwise nucleon-nucleon force, is significant. Moreover, the Coulomb interaction and relativistic effects show their influence in the observables of the breakup reaction. All these effects vary with energy and appear with different strength in certain observables and phase space regions, what calls for systematic investigations of a possibly rich set of observables determined in a wide range of energies. The next step in complication of the system are studies of reactions involving 4 nucleonsmore sensitive, as expected, to subtle dynamics beyond the pairwise interaction. A brief survey of recent and planned experiments in the 3- and 4-nucleon systems is given.

Stephan, E.; Kistryn, St.; Kalantar-Nayestanaki, N.

2014-08-01

253

Free space optical communication flight mission: simulations and experimental results on ground level demonstrator  

NASA Astrophysics Data System (ADS)

In the context of the increasing demand in high-speed data link for scientific, planetary exploration and earth observation missions, the Italian Space Agency (ASI), involving Thales Alenia Space as prime, the Polytechnic of Turin and other Italian partners, is developing a program for feasibility demonstration of optical communication system with the goal of a prototype flight mission in the next future. We have designed and analyzed a ground level bidirectional Free Space Optical Communication (FSOC) Breadboard at 2.5Gbit/s working at 1550nm as an emulator of slant path link. The breadboard is full-working and we tested it back-toback, at 500m and 2.3km during one month. The distances were chosen in order to get an equivalent slant path cumulative turbulence in a ground level link. The measurements campaign was done during the day and the night time and under several weather conditions, from sunny, rainy or windy. So we could work under very different turbulence conditions from weak to strong turbulence. We measured the scintillation both, on-axis and off-axis by introducing known misalignments at the terminals, transmission losses at both path lengths and BER at both receivers. We present simulations results considering slant and ground level links, where we took into account the atmospheric effects; scintillation, beam spread, beam wander and fade probability, and comparing them with the ground level experimental results, we find a good agreement between them. Finally we discuss the results obtained in the experimentation and in the flight mission simulations in order to apply our experimental results in the next project phases.

Mata Calvo, Ramon; Ferrero, Valter; Camatel, Stefano; Catalano, Valeria; Bonino, Luciana; Toselli, Italo

2009-05-01

254

Retained gas sampler extractor mixing and mass transfer rate study: Experimental and simulation results  

SciTech Connect

Research staff at Pacific Northwest National Laboratory conducted experimental testing and computer simulations of the impeller-stirred Retained Gas Sampler (RGS) gas extractor system. This work was performed to verify experimentally the effectiveness of the extractor at mixing viscous fluids of both Newtonian and non-Newtonian rheology representative of Hanford single- and double-shell wastes, respectively. Developing the computational models and validating their results by comparing them with experimental results would enable simulations of the mixing process for a range of fluid properties and mixing speeds. Five tests were performed with a full-scale, optically transparent model extractor to provide the data needed to compare mixing times for fluid rheology, mixer rotational direction, and mixing speed variation. The computer model was developed and exercised to simulate the tests. The tests demonstrated that rotational direction of the pitched impeller blades was not as important as fluid rheology in determining mixing time. The Newtonian fluid required at least six hours to mix at the hot cell operating speed of 3 rpm, and the non-Newtonian fluid required at least 46 hours at 3 rpm to become significantly mixed. In the non-Newtonian fluid tests, stagnant regions within the fluid sometimes required days to be fully mixed. Higher-speed (30 rpm) testing showed that the laminar mixing time was correlated to mixing speed. The tests demonstrated that, using the RGS extractor and current procedures, complete mixing of the waste samples in the hot cell should not be expected. The computer simulation of Newtonian fluid mixing gave results comparable to the test while simulation of non-Newtonian fluid mixing would require further development. In light of the laboratory test results, detailed parametric analysis of the mixing process was not performed.

Recknagle, K.P.; Bates, J.M.; Shekarriz, A.

1997-11-01

255

Future directions in high energy electron-positron experimentation  

SciTech Connect

In this report, the possibilities of studying particle physics at the TeV scale with high energy electron-positron linear colliders are discussed. A status report on the SLC and the MARK II program is given to provide some insights on the feasibility of experiments at linear colliders. The technical issues in going from SLC to the development of TeV colliders are briefly discussed. Some of the elements of the e/sup +/e/sup -/ experimental environment which differentiate it from that in hadron colliders and give examples of processes particularly well suited to attack by e/sup +/e/sup -/ annihilation are summarized. Finally, some concluding remarks are given. 8 refs., 10 figs., 2 tabs.

Trilling, G.H.

1988-09-01

256

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=-3.66731017 N/m2 and a fourth order electroelastic tensor value of e3111=1.7212108 m/V.

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

2010-10-01

257

Experimental results in nonlinear compensation of a one degree-of-freedom magnetic suspension  

NASA Technical Reports Server (NTRS)

Nonlinear control techniques are of increasing interest in magnetic bearing applications. A one-degree-of-freedom magnetic suspension system has been constructed to serve as a test system for nonlinear control. The objective of this effort is to build an accurate model for the nonlinear suspension dynamics and to show the advantages of compensating for these nonlinearities by using a nonlinear controller. The results obtained with a nonlinear controller are experimentally demonstrated as superior to those obtained with a linear controller. Specifically, a controller which contains a force-control block yields transient responses which are largely independent of the operating point air gap.

Trumper, David L.; Sanders, James C.; Nguyen, Tiep H.; Queen, Michael A.

1992-01-01

258

Comparison of Theoretical Stresses and Deflections of Multicell Wings with Experimental Results Obtained from Plastic Models  

NASA Technical Reports Server (NTRS)

The experimental deflections and stresses of six plastic multicell-wing models of unswept, delta, and swept plan form are presented and compared with previously published theoretical results obtained by the electrical analog method. The comparisons indicate that the theory is reliable except for the evaluation of stresses in the vicinity of the leading edge of delta wings and the leading and trailing edges of swept wings. The stresses in these regions are questionable, apparently because of simplifications employed in idealizing the actual structure for theoretical purposes and because of local effects of concentrated loads.

Zender, George W

1956-01-01

259

Experimental and Theoretical Results in Output-Trajectory Redesign for Flexible Structures  

NASA Technical Reports Server (NTRS)

In this paper we study the optimal redesign of output trajectory for linear invertible systems. This is particularly important for tracking control of flexible structures because the input-state trajectories that achieve the required output may cause excessive vibrations in the structure. A trade-off is then required between tracking and vibrations reduction. We pose and solve this problem as the minimization of a quadratic cost function. The theory is developed and applied to the output tracking of a flexible structure and experimental results are presented.

Dewey, J. S.; Devasia, Santosh

1996-01-01

260

Preliminary QCSEE program - Test results. [Quiet Clean Short-haul Experimental Engine  

NASA Technical Reports Server (NTRS)

Preliminary results are reported for the Quiet Clean Short-haul Experimental Engine (QCSEE) program initiated by NASA in 1974 to develop propulsion system technology suitable for powered-lift short-range commercial aircraft. The QCSEE technology also has applications to the proposed U.S. Navy V/STOL aircraft. Emphasis in the QCSEE program is placed on developing engines with low noise characteristics; in addition, the power plants are required to conform to EPA 1979 pollutant emissions standards. Thrust performance, fan design, and thrust/weight ratio are discussed for both the over-the-wing and under-the-wing engine configurations under study.

Ciepluch, C. C.

1977-01-01

261

Design oriented simulation for plasma arc cutting consumables and experimental validation of results  

NASA Astrophysics Data System (ADS)

Electrode and nozzle erosion mechanisms in plasma arc cutting processes of mild steel have been studied while designing a prototype mono-gas plasma torch, operating in the range 25-160 A. The correlation between the distribution of different quantities inside the plasma chamber and the erosion mechanisms of the hafnium emitter surface and of the nozzle inner surfaces have been investigated by means of a 2D ANSYS FLUENT-based numerical model, with the final aim of optimizing the overall performances of the prototype. Modelling and numerical simulation have allowed better understanding of the physical phenomena evidenced by experimental results and have suggested successful design solutions for consumables (in particular nozzle, electrode and primary gas diffusers). The correlation between the results of experimental tests and numerical simulations has proven useful in overcoming the critical aspects initially pointed out, significantly improving the expected lifetime of consumables. Results have been analyzed with respect to plasma behaviour, and conclusions have been drawn, concerning the powerfulness of numerical simulation as a tool for designing plasma cutting torches.

Colombo, V.; Concetti, A.; Ghedini, E.; Dallavalle, S.

2011-06-01

262

Experimental results for a two-dimensional supersonic inlet used as a thrust deflecting nozzle  

NASA Astrophysics Data System (ADS)

Nearly all supersonic V/STOL aircraft concepts are dependent on the thrust deflecting capability of a nozzle. In one unique concept, referred to as the reverse flow dual fan, not only is there a thrust deflecting nozzle for the fan and core engine exit flow, but because of the way the propulsion system operates during vertical takeoff and landing, the supersonic inlet is also used as a thrust deflecting nozzle. This paper presents results of an experimental study to evaluate the performance of a supersonic inlet used as a thrust deflecting nozzle for this reverse flow dual fan concept. Results are presented in terms of nozzle thrust coefficient and thrust vector angle for a number of inlet/nozzle configurations. Flow visualization and nozzle exit flow survey results are also shown.

Johns, Albert L.; Burstadt, Paul L.

263

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.; Prez, J. P.; Ramis, J. P.; Sim, C.; Simon, S.; Weil, J. A.

2010-06-01

264

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 110C 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 200C 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 10C 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

265

Experimental results of a new system using microwaves for vision correction  

NASA Astrophysics Data System (ADS)

Technology is in development to correct vision without the use of lasers or cutting of the eye. Many current technologies used to reshape the cornea are invasive, in that either RF needles are placed into the cornea or a flap is cut and then a laser used to ablate the cornea in the optical zone. Keraflex, a therapeutic microwave treatment, is a noninvasive, non-incisional refractive surgery procedure capable of treating myopia (nearsightedness). The goal is to create a predictable refractive change in the optical zone, while preserving the epithelium and deeper structures of the eye. A further goal is to avoid incisions and damage to the epithelium which both require a post-treatment healing period. Experimental work with fresh porcine eyes examined the following variables: duration of the RF pulse, RF power level, coolant amount and timing, electrode spacing, applanation force against the eye, initial eye temperature, and age of eye. We measured curvature changes of the eye with topography, Scheimpflug, Wavefront aberrometry or other means to characterize diopter change as an important endpoint. Other assessment includes evaluation of a fine white ring seen in the cornea following treatment. Dose studies have been done to correlate the treated region with energy delivered. The timing and dosing of energy and cooling were investigated to achieve the target diopter change in vision.

Ryan, Thomas P.; Pertaub, Radha; Meyers, Steven R.; Dresher, Russell P.; Scharf, Ronald

2009-02-01

266

Community annual storage energy system, cases simulation model and results  

Microsoft Academic Search

The components, operation, energy demand and costs of the Community Annual Storage Energy System, (CASES) which stores waste heat from district cooling in the summer and recycles it for winter district heating are described, and an analysis of the performance and economics of the system using computer simulations is presented. The results are presented in terms of capital required, operating

1978-01-01

267

Universe Clinopyroxene barometer -recalibrations on the results of the orthopyroxene thermobarometry and experimental results and applications to the clinopyroxene geotherms  

NASA Astrophysics Data System (ADS)

The internal exchange of Jd-Di components on clinopyroxene allow to calibrate the universal clinopyroxene thermobarometer (Ashchepkov, 2001; 2002; 2003) based on experimental data for different systems including peridotitic, eclogitic and igneous which are represented by the augite cumulates as well as salites from the basic granulates from low crust. The equation to the peridotitic system was calibrated on the results of the othopyroxene thermobarometry (Brey. Kohler,1990- McGregor,1974). Modifications allow receiving the better agreement with the orthopyroxene estimates and results of polymineral thermobarometry (Brey, Kohler, 1990) as well as the clinopyroxene thermobarometry (Nimis, Taylor, 2000). The following equation allows working with the peridotite of the mantle lithosphere beneath cratons (30-80) kbar. P(Ash2009)=0.32 (1-0.2*Na/Al+0.012*Fe/Na)*Kd^(3/4)*ToK/(1+Fe)-35*ln(1273/ToK)*(Al+Ti+2.5Na+1.5Fe3+)+(0.9-CaO)*10+Na20/Al2O3*ToK /200 with the second iteration P=(0.0000002* P4 +0.000002+P^3-0.0027*P^2+1.2241*P) Checking of the HP experiments (Brey et al 2008, Walter, 1998; Falloon, Green, 1989; Dasgupta et al., 2007 etc.) it show the precision close to those of the best barometers (McGregor, 1974) ~5-7 but much more wider compositional range including metasomatic associations and The equation for the Al - rich assemblages allow to obtain the pressure estimates fro the megacrystalls and Al - rich peridotitic clinopyroxenes from the mantle xenoliths carried by alkaline basalts: P(Ash2009)=0.035*Kd*ToK(1+2.44Fe)-50.2 ln(1273/ToK) (Al+Ti+Na) Together with the clinopyroxene thermometer (Nimis, Taylor, 2000) it produces the TP estimates very close to those obtained with (Brey, Kohler, 1990) and values of experiments for the melting of basalts. The meagacrystalls show the polybaric origin and their range of estimated pressure corresponds well to determined for mantle peridotites and pyroxenites. The clinopyroxene geotherms for S. Africa (Boyd, Nixon, 1974), Siberia (Boyd et al., 1997) and North America (Kopylova et al., 1998) are reproducing the TP estimates b set the values for all mantle associations simultaneously. Such geotherms show the complex nature and wide ranges for TP gradients and variations of temperatures at the same level for the large pipes. This I results of the joining subduction, conductive and advective TP of several melts portions passed through the mantle columns. The vast heating and metasomatic modifications were manly produced by the The eclogite geotherms for the kimberlites reveal two branches - LT close to subduction and HT close to the TP path pf protokimberlites determined by megacrystalline assemblages. The TP values for the typical subduction eclogites (Dora Maira, East China, Tibet) reveal the range of pressures from 11 to 45 kbars and varying gradients mostly close to LT subduction type. The exact values are highly dependent on the thermometer used. The Krough, 1988 and slightly modified (Nimis, Taylor , 2000) give comparable results. Grant RBRF 05-05-64718.

Ashchepkov, I. V.

2009-04-01

268

Measurements of energy distribution in microwave plasmas of N2 and He and comparisons with results for H2  

NASA Technical Reports Server (NTRS)

An electrothermal propulsion concept utilizing a microwave plasma system as the mechanism to convert electromagnetic energy into translational energy of the flowing gas is being investigated. Specifically, this study compares the energy transfer characteristics of three different gases, H2, N2, and He, to gain some insight as to the dominant energy transfer processes present in a microwave plasma. A calorimetric experimental system has been designed and built enclosing the microwave plasma system to accurately determine the net energy transferred to the flowing gas. Results are obtained for N2 and He discharges and compared with previously reported experimental results for H2.

Chapman, R.; Hawley, M. C.

1984-01-01

269

Natural frequencies of two bubbles in a compliant tube: Analytical, simulation, and experimental results  

PubMed Central

Motivated by various clinical applications of ultrasound contrast agents within blood vessels, the natural frequencies of two bubbles in a compliant tube are studied analytically, numerically, and experimentally. A lumped parameter model for a five degree of freedom system was developed, accounting for the compliance of the tube and coupled response of the two bubbles. The results were compared to those produced by two different simulation methods: (1) an axisymmetric coupled boundary element and finite element code previously used to investigate the response of a single bubble in a compliant tube and (2) finite element models developed in comsol Multiphysics. For the simplified case of two bubbles in a rigid tube, the lumped parameter model predicts two frequencies for in- and out-of-phase oscillations, in good agreement with both numerical simulation and experimental results. For two bubbles in a compliant tube, the lumped parameter model predicts four nonzero frequencies, each asymptotically converging to expected values in the rigid and compliant limits of the tube material. PMID:22088008

Jang, Neo W.; Zakrzewski, Aaron; Rossi, Christina; Dalecki, Diane; Gracewski, Sheryl

2011-01-01

270

Fuel-rich, catalytic reaction experimental results. [fuel development for high-speed civil transport aircraft  

NASA Technical Reports Server (NTRS)

Future aeropropulsion gas turbine combustion requirements call for operating at very high inlet temperatures, pressures, and large temperature rises. At the same time, the combustion process is to have minimum pollution effects on the environment. Aircraft gas turbine engines utilize liquid hydrocarbon fuels which are difficult to uniformly atomize and mix with combustion air. An approach for minimizing fuel related problems is to transform the liquid fuel into gaseous form prior to the completion of the combustion process. Experimentally obtained results are presented for vaporizing and partially oxidizing a liquid hydrocarbon fuel into burnable gaseous components. The presented experimental data show that 1200 to 1300 K reaction product gas, rich in hydrogen, carbon monoxide, and light-end hydrocarbons, is formed when flowing 0.3 to 0.6 fuel to air mixes through a catalyst reactor. The reaction temperatures are kept low enough that nitrogen oxides and carbon particles (soot) do not form. Results are reported for tests using different catalyst types and configurations, mass flowrates, input temperatures, and fuel to air ratios.

Rollbuhler, Jim

1991-01-01

271

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

272

Comparison of experimental and analytical results for free vibration of laminated composite plates  

SciTech Connect

Fibrous composite materials are being increasingly employed in high performance structures, including pressured vessel and piping applications. These materials are usually used in the form of laminated flat or curved plates, and the understanding of natural frequencies and the corresponding mode shapes is essential to a reliable structural design. Although many references have been published on analytical study of laminated composite plates, a limited number of experimental studies have appeared for dealing with vibration characteristics of the plates. This paper presents both experimental and analytical results for the problems. In the experiment, the holographic interferometry is used to measure the resonant frequencies and corresponding mode shapes of six-layered CFRP (carbon fiber reinforced plastic) composite plates. The material constants of a lamina are calculated from fiber and matrix material constants by using some different composite rules. With the calculated constants, the natural frequencies of the laminated CFRP plates are theoretically determined by the Ritz method. From the comparison of two sets of the results, the effect of choosing different composite rules is discussed in the vibration study of laminated composite plates.

Maryuama, Koichi; Narita, Yoshihiro; Ichinomiya, Osamu [Hokkaido Inst. of Tech., Sapporo (Japan). Dept. of Mechanical Engineering

1995-11-01

273

A Review of Out-of-School Time Program Quasi-Experimental and Experimental Evaluation Results. Out-of-School Time Evaluation Snapshot.  

ERIC Educational Resources Information Center

As the amount of resources allocated to out-of-school (OST) programming and policymakers' demands for research-based results increase, there is increasing interest in rigorous research designs to examine OST program outcomes. This issue of "Out-of-School Time Evaluation Snapshots" reviews 27 quasi-experimental and experimental OST evaluations and

Little, Priscilla M. D.; Harris, Erin

274

Experimental results on the design for the APS PID global orbit control system.  

SciTech Connect

The Advanced Photon Source third generation synchrotrons light source needs a stabilized particle beam position to produce high brightness and low emittance radiation. Global orbit correction control is introduced and is utilized to satisfy the demanding needs of the accelerator. This paper presents the experimental results for determining an effective and optimal controller to meet the global orbit correction requirements. These requirements include frequency/time domain demands consisting of vibrational noise attenuation, limiting of controller gains for stability and improving the system time response. Experiments were conducted with a digital signal processor implementing various PID sets to make comparisons between simulations and experiments. Measurements at these PID sets supported the results of software simulation.

Chung, Y.; Kirchman, J. A.

1997-12-05

275

Low pollution combustor designs for CTOL engines - Results of the Experimental Clean Combustor Program  

NASA Technical Reports Server (NTRS)

The NASA/Pratt & Whitney Aircraft Experimental Clean Combustor Program is a multi-year, major contract effort. Primary program objectives are the generation of combustor technology for development of advanced commercial CTOL engines with lower exhaust emissions than current aircraft and demonstration of this technology in a full-scale JT9D engine in 1976. This paper describes the pollution and performance goals, Phase I and II test results, and the Phase III combustor hardware, pollution sampling techniques, and test plans. Best results were obtained with the Vorbix concept which employs multiple burning zones and improved fuel preparation and distribution. Substantial reductions were achieved in all pollutant categories, meeting the 1979 EPA standards for NOx, THC, and smoke when extrapolated to JT9D cycle conditions. The Vorbix concept additionally demonstrated the capability for acceptable altitude relight and did not appear to have unsolvable durability or exit temperature distribution problems.

Roberts, R.; Peduzzi, A.; Niedzwiecki, R. W.

1976-01-01

276

Experimental and Statistical Evaluation of Cutting Methods in Relation to Specific Energy and Rock Properties  

NASA Astrophysics Data System (ADS)

In a processing plant, natural stone can be cut by methods such as circular sawing (CS), frame sawing (FS), water jet cutting (WJC) and abrasive water jet cutting (AWJC). The efficiency of cutting systems can be compared using various parameters. In this study, the specific energy values were determined and compared to evaluate the efficiency of rock-cutting methods. Rock-cutting experiments were performed on 12 different types of rock samples using a circular sawing machine and an AWJC machine. The experimental results showed that the specific energy values in AWJC were generally higher than in CS. In addition, the relationships between specific energy values and rock properties were explained in this study. The Shore hardness and abrasion resistance were found to be strongly related to the specific energy values, and according to these parameters prediction charts of specific energy values were created.

Engin, Irfan Celal; Bayram, Fatih; Yasitli, Nazmi Erhan

2013-07-01

277

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

278

Experimental investigation of high-energy photon splitting in atomic fields  

E-print Network

The new data analysis of the experiment, where the photon splitting in the atomic fields has been observed for the first time, is presented. This 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, the statistics of $1.6\\cdot 10^9$ photons incident on the BGO target was collected. About 400 candidates to the photon splitting events were reconstructed. Within the attained experimental accuracy, the experimental results are consistent with the cross section calculated exactly in an atomic field. The predictions obtained in the Born approximation significantly differ from the experimental results.

Akhmadaliev, S Z; 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; Akhmadaliev, Sh Z; Kezerashvili, G Ya; Panin, V S; Tikhonov, Yu.A.

2002-01-01

279

Experimental investigation of high-energy photon splitting in atomic fields  

E-print Network

The new data analysis of the experiment, where the photon splitting in the atomic fields has been observed for the first time, is presented. This 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, the statistics of $1.6\\cdot 10^9$ photons incident on the BGO target was collected. About 400 candidates to the photon splitting events were reconstructed. Within the attained experimental accuracy, the experimental results are consistent with the cross section calculated exactly in an atomic field. The predictions obtained in the Born approximation significantly differ from the experimental results.

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

2001-11-27

280

Smectite clays in Mars soil - Evidence for their presence and role in Viking biology experimental results  

NASA Technical Reports Server (NTRS)

Evidence for the presence of smectite clays in Martian soils is reviewed and results of experiments with certain active clays simulating the Viking biology experiments are reported. Analyses of Martian soil composition by means of X-ray fluorescence spectrometry and dust storm spectroscopy and Martian geological history strongly suggest the presence of a mixture of weathered ferro-silicate minerals, mainly nontronite and montmorillonite, accompanied by soluble sulphate salts, as major constituents. Samples of montmorillonite and nontronite incubated with (C-14)-formate or the radioactive nutrient medium solution used in the Viking Labeled Release experiment, were found to produce patterns of release of radioactive gas very similar to those observed in the Viking experiments, indicating the iron-catalyzed decomposition of formate as the reaction responsible for the Viking results. The experimental results of Hubbard (1979) simulating the results of the Viking Pyrolytic Release experiment using iron montmorillonites are pointed out, and it is concluded that many of the results of the Viking biology experiments can be explained in terms of the surface activity of smectite clays in catalysis and adsorption.

Banin, A.; Rishpon, J.

1979-01-01

281

Experimental study on temperature characteristics and energy conversion in packed bed reactor with dielectric barrier discharge  

NASA Astrophysics Data System (ADS)

The temperature characteristics and energy conversion in packed bed reactor combined with a dielectric barrier discharge (DBD) plasma was investigated experimentally. The pellet temperatures of two types packed bed reactor, cylindrical reactor and parallel-plate reactor, was measured in conditions of various inlet voltage of DBD plasma. The relationship between pellet temperature of the packed bed and applied voltage of DBD plasma was discovered. The experimental result indicates a tendency that the pellet temperature of packed bed increases as the applied voltage of inlet plasma increases. When the voltage of inlet plasma is high enough, the pellet temperature increment decreases. Simultaneously,the packed bed temperature is sensitive to the inlet plasma energy and there is a potential application to heat exchanger. Moreover the proportion of energy consumption of plasma inputting into packed bed reactor was analyzed and calculated. The mechanisms that electrical energy of inlet plasma is transformed into heat energy in the two phases, gaseous and pellets of the packed bed reactor are different. The energy consumption in pellet phase is dielectric polarization loss and depends on packed bed geometry and DBD plasma etc. The energy consumption in gaseous phase is plasma sheath procedure. The important factors effecting on gas discharge are gaseous component and voltage, frequency of power.

Li, Sen; Tang, Zuchen; Gu, Fan

2010-10-01

282

Experimental Tests of Cascade Theory at High Energies  

Microsoft Academic Search

Results of simultaneous measurement of the radial position and angular orientation of electrons in ten high-energy (180-2000-BeV) electromagnetic cascades are given. Six of these cascades were developed in pure emulsion, while four were developed in a lead-emulsion sandwich stack. Numerical calculations of the angular distributions, both within approximation B and the core approximation, are presented. Calculations on the mixed radial-angular

R. Holynski; W. V. Jones; K. Pinkau

1968-01-01

283

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

284

Review of Recent Results from the RHIC Beam Energy Scan  

E-print Network

We review recent results from the RHIC beam energy scan (BES) program, aimed to study the Quantum Chromodynamics (QCD) phase diagram. The main goals are to search for the possible phase boundary, softening of equation of state or first order phase transition, and possible critical point. Phase-I of the BES program has recently concluded with data collection for Au+Au collisions at center-of-mass energies ($\\sqrt{s_{NN}}$) of 7.7, 11.5, 19.6, 27, and 39 GeV. Several interesting results are observed for these lower energies where the net-baryon density is high at the mid-rapidity. These results indicate that the matter formed at lower energies (7.7 and 11.5 GeV) is hadron dominated and might not have undergone a phase transition. In addition, the centrality dependence of freeze-out parameters is observed for the first time at lower energies, slope of directed flow for (net)-protons measured versus rapidity shows an interesting behavior at lower energies, and higher moments of net-proton show deviation from Skellam expectations at lower energies. An outlook for the future BES Phase-II program is presented and efforts for the detailed study of QCD phase diagram are discussed.

Lokesh Kumar

2013-11-14

285

Distribution of fasciolosis in Kansas, with results of experimental snail susceptibility studies.  

PubMed

A total of 278 veterinarians throughout Kansas were sent mail-in survey forms asking specific questions relating to their experience with fasciolosis in their practice area. Replies were received from 178 (64%) veterinarians representing six practice types; one-third reported having seen cases of fasciolosis in their practice. The results of our survey indicate that the majority of the cattle diagnosed with liver fluke disease in Kansas are imported from other areas of the USA. However, in both central and southeastern regions of Kansas, some cattle that had never been out of the state were infected with Fasciola hepatica. Thus, these areas of Kansas should be considered endemic for liver fluke disease. Methods of diagnosis, types of operations, and improvements seen after treatment were also discussed. In order to ascertain the existence of one or more possible snail intermediate hosts within Kansas, five species of lymnaeid snails were collected from central and southeastern parts of the state and tested for their susceptibility to infection by Fasciola hepatica. The snails collected included Pseudosuccinea columella, Fossaria obrussa, Fossaria bulimoides, Fossaria parva and Fossaria dalli. Of these, Pseudosuccinea columella and Fossaria bulimoides proved susceptible to experimental infection by Fasciola hepatica. Metacercariae obtained from experimentally infected snails were used to infect both a weanling calf thereby completing the life cycle of the parasite. This report is the first to identify the existence of suitable snail intermediate hosts for Fasciola hepatica in Kansas. PMID:7754605

McKown, R D; Ridley, R K

1995-02-01

286

The Theory of Uncertainty in Derived Results: Properties of Equations Representing Physicochemical Experimental Systems  

E-print Network

The appropriate uncertainty-correlation between a derived variable (Ym) and its experimental variables (Xi's) is worked out, and the feasibility of its use in designing required experiments or to validate desired results and hence a possible data evaluation model itself, is discussed. It is clarified that uncertainty-translation (say: ui(s) INTO em, accompanying a data-transformation: Xi(s) INTO Ym) is a systematic change governed by parameters of a given system-specific relationship (SSR) of Ym with Xi(s) and is independent of uncertainty-ui and/ or data-Xi source. Similarly the limiting value of error (DELTAm) in Ym is signified to be a property of SSR rather than of measurement, thereby classifying all possible derived systems (SSRs) into two groups as: Gr. (I), where SSRs that can never cause DELTAm to be zero and Gr. (II), those enabling DELTAm to be even zero. Truly an insight into how requirement for basically an experimental study be dictated by a corresponding theoretical step (Xi(s) INTO Ym(s)) is p...

Datta, B P

2007-01-01

287

Fate and Transport of Graphene Oxide in Granular Porous Media: Experimental Results and Modeling  

NASA Astrophysics Data System (ADS)

Although graphene oxide (GO) has been used in many applications to improve human life quality, its environmental fate and behavior are still largely unknown. In this work, a range of laboratory experiments were conducted to explore the aggregation, deposition, and transport mechanisms of GO nano-sheets in porous media under various conditions. Stability experimental data showed that both cation valence and pH showed significant effect on the aggregation of GO sheets. The measured critical coagulation concentrations were in good agreement with the predictions of the extended Schulze-Hardy rule. Sand column experimental results indicated that deposition and transport of GO in porous media were strongly dependent on solution ionic strength. Particularly, GO showed high mobility under low ionic strength conditions in both saturated and unsaturated columns. Increasing ionic strength dramatically increased the retention of GO in porous media, mainly through secondary-minimum deposition. Recovery rates of GO in unsaturated sand columns were lower than that in saturated columns under the same ionic strength conditions, suggesting moisture content also played an important role in the retention of GO in porous media. Findings from the bubble column experiments showed that the GO did not attach to the air-water interface, which is consistent with the XDLVO predictions. Additional retention mechanisms, such as film straining, thus could be responsible to the reduced mobility of GO in unsaturated porous media. The breakthrough curves of GO in saturated and unsaturated columns could be accurately simulated by an advection-dispersion-reaction model.

Gao, Bin

2014-05-01

288

The Magnetic Signature of Iintact and Altered Magnetofossils: Experimental and Theoretical Results  

NASA Astrophysics Data System (ADS)

Recently developed rock magnetic techniques (FORC, FMR) allow the detection of magnetofossils in sediment containing mixtures of magnetic minerals. Magnetofossil appear to be widespread in marine and freshwater sediments. In many cases, they account for >50% of the remanent magnetization. Their widespread occurrence and preservation potential in sediments that do not undergo sulfate reduction need to be considered in environmental magnetism and relative paleointensity studies. This requires a fully quantitative characterization of authigenic and terrigenous magnetic minerals in sediment. Magnetofossil detection is currently based on their magnetic similarity to non-interacting, uniaxial, single-domain particles. This similarity, however, might be limited to the case of isolated, linear chains of magnetite particles. Other magnetofossil configurations, related to bacteria producing double chains and multiple chains, as well as chain collapse during sediment diagenesis, might not bear the same signature of isolated chains. Therefore, the theoretical and experimental investigation of such structures is of paramount importance for the correct interpretation of sediment signatures. We will present experimental results and micromagnetic simulations of different magnetofossil configurations, as they can be deduced from TEM and mechanical considerations. Although the overall signature of such configurations is very sensitive to the geometric arrangement of magnetosomes, all of them retain specific FORC features useful for their identification.

Egli, R.; Steinmller, S.; Winklhofer, M.

2012-12-01

289

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.; Ptzold, O.; Gerbeth, G.; Stelter, M.

2007-07-01

290

EASE (Experimental Assembly of Structures in EVA) overview of selected results  

NASA Technical Reports Server (NTRS)

Experimental Assembly of Structures in EVA (EASE) objectives, experimental protocol, neutral buoyancy simulation, task time distribution, assembly task performance, metabolic rate/biomedical readouts are summarized. This presentation is shown in charts, figures, and graphs.

Akin, David L.

1987-01-01

291

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

SciTech Connect

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. [Department of Radiation Oncology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107 (United States); Department of Radiation Oncology, University Hospitals Case Medical Center, Cleveland, Ohio 44106 (United States); Department of Radiation Oncology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107 (United States); Department of Radiation Oncology, University Hospitals Case Medical Center, Cleveland, Ohio 44106 (United States)

2012-11-15

292

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. PMID:23127089

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

2012-01-01

293

Analytical and experimental dosimetry techniques for calibrating a low energy X-ray radiation source  

Microsoft Academic Search

This paper describes the method used to calibrate a large-volume continuous-wave X-ray radiation test chamber. The X-ray tube has a tungsten target and emits a bremsstrahlung X-ray spectrum with end point energies up to 160 keV. Analytical tools and experimental dosimetry techniques were developed to map the radiation field intensity and the resulting dose-deposition profiles in a variety of materials

R. D. Bellem; K. L. Critchfield; R. M. Pelzl; R. D. Pugh; R. W. Tallon

1994-01-01

294

Theoretical and experimental investigation of variable band gap cells in thermophotovoltaic energy conversion  

Microsoft Academic Search

Using a theoretical model for the performance of a thermophotovoltaic (TPV) energy conversion cell, and values of saturation-current density and diode ideality factor obtained experimentally for two types of InCaAs cells, one GaAs, and two Si cells, the TPV efficiency at various temperatures was calculated for these cells. The results disclosed an apparent advantage of InGaAs cells (with band gaps

L. D. Woolf; J. C. Bass; N. B. Elsner

1986-01-01

295

Experimental Study of Airfoil Trailing Edge Noise: Instrumentation, Methodology and Initial Results. M.S. Thesis  

NASA Technical Reports Server (NTRS)

The mechanisms of aerodynamic noise generation at the trailing edge of an airfoil is investigated. Instrumentation was designed, a miniature semiconductor strain-gauge pressure transducer and associated electronic amplifier circuitry were designed and tested and digital signal analysis techniques applied to gain insight into the relationship between the dynamic pressure close to the trailing edge and the sound in the acoustic far-field. Attempts are made to verify some trailing-edge noise generation characteristics as theoretically predicted by several contemporary acousticians. It is found that the noise detected in the far-field is comprised of the sum of many uncorrelated emissions radiating from the vicinity of the trailing edge. These emissions appear to be the result of acoustic energy radiation which has been converted by the trailing-edge noise mechanism from the dynamic fluid energy of independent streamwise 'strips' of the turbulent boundary layer flow.

Manley, M. B.

1980-01-01

296

Motion effects on an IFR hovering task: Analytical predictions and experimental results  

NASA Technical Reports Server (NTRS)

An analytical pilot model incorporating the effects of motion cues and display scanning and sampling is tested by comparing predictions against experimental results on a moving base simulator. The simulated task is that of precision hovering of a VTOL having varying amounts of rate damping, and using separated instrument displays. Motion cue effects are investigated by running the experiment under fixed and moving base conditions, the latter in two modes; full motion, and angular motion only. Display scanning behavior is measured on some of the runs. The results of the program show that performance is best with angular motion only, most probably because a g-vector tilt cue is available to the pilot in this motion condition. This provides an attitude indication even when not visually fixating the attitude display. Vestibular threshold effects are also present in the results because of the display scaling used to permit hovering position control within the motion simulator limits; no washouts are used in the simulator drive signals. The IFR nature of the task results in large decrements in pilot opinion and performance relative to VFR conditions because of the scanning workload. Measurements of scanning behavior are sensitive to motion conditions and show more attention to attitude control under fixed base conditions.

Ringland, R. F.; Stapleford, R. L.; Magdaleno, R. E.

1971-01-01

297

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

298

Fracture mode analysis and related surface deformation during dyke intrusion: Results from 2D experimental modelling  

NASA Astrophysics Data System (ADS)

Surface deformation analysis in volcanic edifices in response to shallow magma intrusion is crucial for assessing volcanic hazards. In this paper, we discuss the effect of dyke propagation mode on surface deformation through 2D laboratory models. Our experimental setup consists of a Hele-Shaw cell, in which a model magma is injected into a cohesive model crust. Using an optical image correlation technique (Particle Imaging Velocimetry), we measured the surface deformation, the displacements and the strain field induced by magma emplacement within the country rock. We identify two types of intrusion morphologies (Types A and B), which exhibit two evolutional stages. During the first stage, both types resulted in a vertical dyke at depth; its propagation was controlled by both shear deformation and tensile opening. The model surface lifted up to form a smooth symmetrical dome, resulting in tensile cracks. During the second stage, Types A and B experiments differ when the dyke reaches a critical depth. In Type A, the intrusion gradually rotates, forming an inclined sheet dipping between 45 and 65. This rotation results in asymmetrical surface uplift and shear failure upon the tip of the dyke. In Type B, the dyke tip interacts with tensile cracks formed during the first stage. This fracture controls the subsequent propagation of the dyke toward the surface. In both types of experiments, intrusions result in surface uplift, which can be accommodated by reverse faults. Our study suggests that dykes propagate as viscous indenters, rather than linear elastic fracturing.

Abdelmalak, M. M.; Mourgues, R.; Galland, O.; Bureau, D.

2012-12-01

299

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

300

Simulation and experimental results of optical and thermal modeling of gold nanoshells.  

PubMed

This paper proposes a generalized method for optical and thermal modeling of synthesized magneto-optical nanoshells (MNSs) for biomedical applications. Superparamagnetic magnetite nanoparticles with diameter of 9.5 1.4 nm are fabricated using co-precipitation method and subsequently covered by a thin layer of gold to obtain 15.8 3.5 nm MNSs. In this paper, simulations and detailed analysis are carried out for different nanoshell geometry to achieve a maximum heat power. Structural, magnetic and optical properties of MNSs are assessed using vibrating sample magnetometer (VSM), X-ray diffraction (XRD), UV-VIS spectrophotometer, dynamic light scattering (DLS), and transmission electron microscope (TEM). Magnetic saturation of synthesized magnetite nanoparticles are reduced from 46.94 to 11.98 emu/g after coating with gold. The performance of the proposed optical-thermal modeling technique is verified by simulation and experimental results. PMID:25063109

Ghazanfari, Lida; Khosroshahi, Mohammad E

2014-09-01

301

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

302

Active vibration absorber for CSI evolutionary model: Design and experimental results  

NASA Technical Reports Server (NTRS)

The development of control of large flexible structures technology must include practical demonstration to aid in the understanding and characterization of controlled structures in space. To support this effort, a testbed facility was developed to study practical implementation of new control technologies under realistic conditions. The design is discussed of a second order, acceleration feedback controller which acts as an active vibration absorber. This controller provides guaranteed stability margins for collocated sensor/actuator pairs in the absence of sensor/actuator dynamics and computational time delay. The primary performance objective considered is damping augmentation of the first nine structural modes. Comparison of experimental and predicted closed loop damping is presented, including test and simulation time histories for open and closed loop cases. Although the simulation and test results are not in full agreement, robustness of this design under model uncertainty is demonstrated. The basic advantage of this second order controller design is that the stability of the controller is model independent.

Bruner, Anne M.; Belvin, W. Keith; Horta, Lucas G.; Juang, Jer-Nan

1991-01-01

303

School Context and Educational Outcomes: Results from a Quasi-Experimental Study  

PubMed Central

In this study we draw on data from a quasi-experimental study to test whether moving into a subsidized housing development in an affluent suburb yields educational benefits to the children of residents, compared to the educations they would have received had they not moved into the development. Results suggest that resident children experienced a significant improvement in school quality compared with a comparison group of students whose parents also had applied for residence. Parents who were residents of the development also displayed higher levels of school involvement compared with the comparison group of non-resident parents, and their children were exposed to significantly lower levels of school disorder and violence within school and spent more time reading outside of school. Living in the development did not influence GPA directly, but did indirectly increase GPA by increasing the time residents spent reading outside of school. PMID:25342878

Casciano, Rebecca; Massey, Douglas S.

2013-01-01

304

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

305

Prestress effects on the eigenfrequencies of the soundboards: experimental results on a simplified string instrument.  

PubMed

This paper presents an experimental study of the effects of prestresses on the vibration behavior of string instruments. These prestresses are created by gluing ribs (crowning) and tensioning string (downbearing). The effects of these prestresses were previously studied numerically for a piano soundboard by Mamou-Mani et al. [J. Acoust. Soc. Am. 123, 2401-2406 (2008)] and analytically for simplified models by Mamou-Mani et al. [Acta Acust. Unit. Acust. 95, 915-926 (2009)]. In the present study, a specified test bench is designed, including a simplified soundboard (a rectangular plate), a bridge, and a single string. The plate is subjected to in-plane and transverse loads. Vibrational eigenmodes are identified using nearfield acoustical holography (NAH) measurement. The evolution of eigenfrequencies with these specific prestresses is studied. The results show the effectiveness of NAH for this purpose and a very good qualitative concordance with previous numerical and analytical calculus. PMID:22280709

Mamou-Mani, Adrien; Le Moyne, Sylvie; Ollivier, Franois; Besnainou, Charles; Frelat, Jol

2012-01-01

306

Results on the energy dependence of cosmic ray charge composition  

NASA Technical Reports Server (NTRS)

Measurements using a balloon-borne ionization spectrometer on the differential energy spectra of the heavy nuclei of the galactic cosmic radiation are reported. The spectra of individual elements up to oxygen and groups of nuclei up through iron were measured up to almost 100 GeV/nucleon. The energy spectrum of the secondary nuclei, B+N, is steeper than that of the primary nuclei, C+O, by gamma = 0.21 + or - .09 in agreement with other authors. The spectral shapes found are reasonably well represented by single power laws between 2 and 60 GeV/nucleon. Data are consistent with the decrease in the secondary to primary ratio found by others above 20 GeV/nucleon, but it shows no evidence for any sudden change in this ratio within counting statistics. The most dramatic finding is that the spectrum of the iron nuclei is flatter than that of the carbon and oxygen nuclei by 0.57 + or - 0.14 of a power. The experimental techniques for charge and energy determination are presented and corrections due to nuclear disintegration and losses of energy out the bottom of the spectrometer are discussed.

Balasubrahmanyan, V. K.; Ormes, J. F.

1973-01-01

307

Collisions induced by halo and weakly bound nuclei around the Coulomb barrier: experimental results at INFN-LNS  

NASA Astrophysics Data System (ADS)

The study of nuclear collisions involving halo or weakly bound nuclei, at energies around the Coulomb barrier, had a considerable interest in the last decade since the peculiar structure of such nuclei can deeply affect the reaction dynamics. In this paper will summarize some of the experimental results obtained by our group at INFN-LNS over the last years in collisions induced by the halo nuclei 6He and nBe and the stable weakly bound nuclei 6Li and 7Li. Very strong entrance channel effects have been observed in elastic scattering, fusion and direct processes comparing collision induced by the 6He and nBe halo nuclei with the ones induced on the same target by their cores 4He and 10Be. Collisions induced by the stable weakly bound nuclei 6Li, 7Li shows some peculiarities in comparison to the ones induced by well bound nuclei, such as absence of usual threshold anomaly in the optical potential and strong competition of complete fusion with incomplete fusion and transfer in the heavy residue production cross sections. Our experimental results are compared with the ones of other authors, in order to give an overview of our present understanding of the discussed topic.

Figuera, P.

2014-05-01

308

Shuttle Damage/Repair from the Perspective of Hypersonic Boundary Layer Transition - Experimental Results  

NASA Technical Reports Server (NTRS)

An overview is provided of the experimental wind tunnel program conducted at the NASA Langley Research Center Aerothermodynamics Laboratory in support of an agency-wide effort to prepare the Shuttle Orbiter for Return-to-Flight. The effect of an isolated protuberance and an isolated rectangular cavity on hypersonic boundary layer transition onset on the windward surface of the Shuttle Orbiter has been experimentally characterized. These experimental studies were initiated to provide a protuberance and cavity effects database for developing hypersonic transition criteria to support on-orbit disposition of thermal protection system damage or repair. In addition, a synergistic experimental investigation was undertaken to assess the impact of an isolated mass-flow entrainment source (simulating pyrolysis/outgassing from a proposed tile repair material) on boundary layer transition. A brief review of the relevant literature regarding hypersonic boundary layer transition induced from cavities and localized mass addition from ablation is presented. Boundary layer transition results were obtained using 0.0075-scale Orbiter models with simulated tile damage (rectangular cavities) of varying length, width, and depth and simulated tile damage or repair (protuberances) of varying height. Cavity and mass addition effects were assessed at a fixed location (x/L = 0.3) along the model centerline in a region of near zero pressure gradient. Cavity length-to-depth ratio was systematically varied from 2.5 to 17.7 and length-to-width ratio of 1 to 8.5. Cavity depth-to-local boundary layer thickness ranged from 0.5 to 4.8. Protuberances were located at several sites along the centerline and port/starboard attachment lines along the chine and wing leading edge. Protuberance height-to-boundary layer thickness was varied from approximately 0.2 to 1.1. Global heat transfer images and heating distributions of the Orbiter windward surface using phosphor thermography were used to infer the state of the boundary layer (laminar, transitional, or turbulent). Test parametrics include angles-of-attack of 30 deg and 40 deg, sideslip angle of 0 deg, freestream Reynolds numbers from 0.02x106 to 7.3x106 per foot, edge-to-wall temperature ratio from 0.4 to 0.8, and normal shock density ratios of approximately 5.3, 6.0, and 12 in Mach 6 air, Mach 10 air, and Mach 6 CF4, respectively. Testing to simulate the effects of ablation from a proposed tile repair concept indicated that transition was not a concern. The experimental protuberance and cavity databases highlighted in this report were used to formulate boundary layer transition correlations that were an integral part of an analytical process to disposition observed Orbiter TPS damage during STS- 114.

Horvath, Thomas J.; Berry, Scott A.; Merski, N. Ronald; Berger, Karen T.; Buck, Gregory M.; Liechty, Derek S.; Schneider, Steven P.

2006-01-01

309

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.

2012-04-01

310

Results of the NASA/General Electric Experimental Clean Combustor Program  

NASA Technical Reports Server (NTRS)

The NASA/General Electric Experimental Clean Combustor Program is a multi-year, major contract effort. Primary program objectives are the generation of technology for development of advanced commercial CTOL engines with lower exhaust emissions than current aircraft and, demonstrations of this technology in a full-scale CF6-50C engine in 1976. This paper describes pollution and performance goals, Phase I and II test results and Phase III hardware, pollution sampling techniques and test plans. Pollution results are presented in emission index and Environmental Protection Agency 1979 Standard Parameters (EPAP). Best results were obtained with a double annular combustor concept. This concept, which incorporates multistage burning, produced EPAP values extrapolated to CF6-50C engine conditions for CO, HC, and NOx of 3.3, 0.3 and 4.5, respectively. These represent respective CO, HC and NOx percentage reductions of 69, 93 and 42%, compared to current CF6-50 engine values. The combustor also met development engine performance requirements.

Gleason, C. C.; Niedzwiecki, R. W.

1976-01-01

311

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. PMID:21196457

Strupp, Christian

2011-01-01

312

Dynamics of Dual Prism Adaptation: Relating Novel Experimental Results to a Minimalistic Neural Model  

PubMed Central

In everyday life, humans interact with a dynamic environment often requiring rapid adaptation of visual perception and motor control. In particular, new visuomotor mappings must be learned while old skills have to be kept, such that after adaptation, subjects may be able to quickly change between two different modes of generating movements (dualadaptation). A fundamental question is how the adaptation schedule determines the acquisition speed of new skills. Given a fixed number of movements in two different environments, will dualadaptation be faster if switches (phase changes) between the environments occur more frequently? We investigated the dynamics of dualadaptation under different training schedules in a virtual pointing experiment. Surprisingly, we found that acquisition speed of dual visuomotor mappings in a pointing task is largely independent of the number of phase changes. Next, we studied the neuronal mechanisms underlying this result and other key phenomena of dualadaptation by relating model simulations to experimental data. We propose a simple and yet biologically plausible neural model consisting of a spatial mapping from an input layer to a pointing angle which is subjected to a global gain modulation. Adaptation is performed by reinforcement learning on the model parameters. Despite its simplicity, the model provides a unifying account for a broad range of experimental data: It quantitatively reproduced the learning rates in dualadaptation experiments for both direct effect, i.e. adaptation to prisms, and aftereffect, i.e. behavior after removal of prisms, and their independence on the number of phase changes. Several other phenomena, e.g. initial pointing errors that are far smaller than the induced optical shift, were also captured. Moreover, the underlying mechanisms, a local adaptation of a spatial mapping and a global adaptation of a gain factor, explained asymmetric spatial transfer and generalization of prism adaptation, as observed in other experiments. PMID:24204643

Arevalo, Orlando; Bornschlegl, Mona A.; Eberhardt, Sven; Ernst, Udo; Pawelzik, Klaus; Fahle, Manfred

2013-01-01

313

Two-stage n-butane flame: A comparison between experimental measurements and modeling results  

SciTech Connect

Two stage autoignition processes in unburned end-gases are generally considered to be responsible for homogeneously-initiated engine knock phenomena. Two-stage flame processes were investigated to achieve a better understanding of the low temperature and high temperature chemistry responsible for this type of autoignition behavior. A stabilized n-butane two-stage flame wax numerically simulated, utilizing a detailed kinetic mechanism involving 141 species and 850 elementary reactions, and results are compared with experimental data obtained from a one dimensional, two-stage flame burner. With the exception of those for butenes and hydroperoxyl radicals, calculated and experimental profiles are found to agree within a factor of two over the entire flame region. Under the fuel rich conditions studied, CH{sub 3}O and OH radicals are found to be the principal reactive radicals in the cool flame region. A decrease in the estimated rate of reactions R + HO{sub 2} = RO + OH (R=C{sub 3}H{sub 5}, CH{sub 3}, C{sub 2}H{sub 5} and C{sub 4}H{sub 7}) is required to obtain agreement of fuel profiles between the two flame zones. In the second stage region, predicted reaction profiles are in general agreement with the experiment, with the exception of formaldehyde and C{sub 4}-oxygenated species, for which consumptions are substantially underestimated. This study suggests that the reaction channel for direct metathesis and stabilized hot adduct formation for the overall process C{sub 4}H{sub 9} + O{sub 2} {yields} C{sub 4}H{sub 8} + HO{sub 2} need further attention.

Corre, C.; Dryer, F.L. [Princeton Univ., NJ (United States); Pitz, W.J.; Westbrook, C.K. [Lawrence Livermore National Lab., CA (United States)

1992-02-01

314

Soft material adhesion characterization for in vivo locomotion of robotic capsule endoscopes: Experimental and modeling results.  

PubMed

The objective of this work is to validate an experimental method and nondimensional model for characterizing the normal adhesive response between a polyvinyl chloride based synthetic biological tissue substrate and a flat, cylindrical probe with a smooth polydimethylsiloxane (PDMS) surface. The adhesion response is a critical mobility design parameter of a Robotic Capsule Endoscope (RCE) using PDMS treads to provide mobility to travel through the gastrointestinal tract for diagnostic purposes. Three RCE design characteristics were chosen as input parameters for the normal adhesion testing: pre-load, dwell time and separation rate. These parameters relate to the RCE?s cross sectional dimension, tread length, and tread speed, respectively. An inscribed central composite design (CCD) prescribed 34 different parameter configurations to be tested. The experimental adhesion response curves were nondimensionalized by the maximum stress and total displacement values for each test configuration and a mean nondimensional curve was defined with a maximum relative error of 5.6%. A mathematical model describing the adhesion behavior as a function of the maximum stress and total displacement was developed and verified. A nonlinear regression analysis was done on the maximum stress and total displacement parameters and equations were defined as a function of the RCE design parameters. The nondimensional adhesion model is able to predict the adhesion curve response of any test configuration with a mean R(2) value of 0.995. Eight additional CCD studies were performed to obtain a qualitative understanding of the impact of tread contact area and synthetic material substrate stiffness on the adhesion response. These results suggest that the nondimensionalization technique for analyzing the adhesion data is sufficient for all values of probe radius and substrate stiffness within the bounds tested. This method can now be used for RCE tread design optimization given a set of environmental conditions for device operation. PMID:25151447

Kern, Madalyn D; Ortega Alcaide, Joan; Rentschler, Mark E

2014-11-01

315

Experimental validation of a novel compact focusing scheme for future energy-frontier linear lepton colliders.  

PubMed

A novel scheme for the focusing of high-energy leptons in future linear colliders was proposed in 2001 [P. Raimondi and A. Seryi, Phys. Rev. Lett. 86, 3779 (2001)]. This scheme has many advantageous properties over previously studied focusing schemes, including being significantly shorter for a given energy and having a significantly better energy bandwidth. Experimental results from the ATF2 accelerator at KEK are presented that validate the operating principle of such a scheme by demonstrating the demagnification of a 1.3GeV electron beam down to below 65nm in height using an energy-scaled version of the compact focusing optics designed for the ILC collider. PMID:24484144

White, G R; Ainsworth, R; Akagi, T; Alabau-Gonzalvo, J; Angal-Kalinin, D; Araki, S; Aryshev, A; Bai, S; Bambade, P; Bett, D R; Blair, G; Blanch, C; Blanco, O; Blaskovic-Kraljevic, N; Bolzon, B; Boogert, S; Burrows, P N; Christian, G; Corner, L; Davis, M R; Faus-Golfe, A; Fukuda, M; Gao, J; Garca-Morales, H; Geffroy, N; Hayano, H; Heo, A Y; Hildreth, M; Honda, Y; Huang, J Y; Hwang, W H; Iwashita, Y; Jang, S; Jeremie, A; Kamiya, Y; Karataev, P; Kim, E S; Kim, H S; Kim, S H; Kim, Y I; Komamiya, S; Kubo, K; Kume, T; Kuroda, S; Lam, B; Lekomtsev, K; Liu, S; Lyapin, A; Marin, E; Masuzawa, M; McCormick, D; Naito, T; Nelson, J; Nevay, L J; Okugi, T; Omori, T; Oroku, M; Park, H; Park, Y J; Perry, C; Pfingstner, J; Phinney, N; Rawankar, A; Renier, Y; Resta-Lpez, J; Ross, M; Sanuki, T; Schulte, D; Seryi, A; Shevelev, M; Shimizu, H; Snuverink, J; Spencer, C; Suehara, T; Sugahara, R; Takahashi, T; Tanaka, R; Tauchi, T; Terunuma, N; Toms, R; Urakawa, J; Wang, D; Warden, M; Wendt, M; Wolski, A; Woodley, M; Yamaguchi, Y; Yamanaka, T; Yan, J; Yokoya, K; Zimmermann, F

2014-01-24

316

Experimental demonstration of energy-chirp compensation by a tunable dielectric-based structure.  

PubMed

A tunable energy-chirp compensator was used to remove a correlated energy chirp from the 60-MeV beam at the Brookhaven National Laboratory Accelerator Test Facility. The compensator operates through the interaction of the wakefield of the electron bunch with itself and consists of a planar structure comprised of two alumina bars with copper-plated backs separated by an adjustable beam aperture. By changing the gap size, the correlated energy chirp of the electron bunch was completely removed. Calculations show that this device, properly scaled to account for the electron bunch charge and length, can be used to remove residual correlated energy spread at the end of the linacs used for free-electron lasers. The experimental results are shown to be in good agreement with numerical simulations. Application of this technique can significantly simplify linac design and improve free-electron lasers performance. PMID:24702378

Antipov, S; Baturin, S; Jing, C; Fedurin, M; Kanareykin, A; Swinson, C; Schoessow, P; Gai, W; Zholents, A

2014-03-21

317

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

318

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

2013-01-01

319

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

320

Experimental demonstration of quantitation errors in MR spectroscopy resulting from saturation corrections under changing conditions  

NASA Astrophysics Data System (ADS)

Metabolite concentration measurements in in vivo NMR are generally performed under partially saturated conditions, with correction for partial saturation performed after data collection using a measured saturation factor. Here, we present an experimental test of the hypothesis that quantitation errors can occur due to application of such saturation factor corrections in changing systems. Thus, this extends our previous theoretical work on quantitation errors due to varying saturation factors. We obtained results for two systems frequently studied by 31P NMR, the ischemic rat heart and the electrically stimulated rat gastrocnemius muscle. The results are interpreted in light of previous theoretical work which defined the degree of saturation occurring in a one-pulse experiment for a system with given spin-lattice relaxation times, T1s, equilibrium magnetizations, M0s, and reaction rates. We found that (i) the assumption of constancy of saturation factors leads to quantitation errors on the order of 40% in inorganic phosphate; (ii) the dominant contributor to the quantitation errors in inorganic phosphate is most likely changes in T1; (iii) T1 and M0 changes between control and intervention periods, and chemical exchange contribute to different extents to quantitation errors in phosphocreatine and ?-ATP; (iv) relatively small increases in interpulse delay substantially decreased quantitation errors for metabolites in ischemic rat hearts; (v) random error due to finite SNR led to approximately 4% error in quantitation, and hence was a substantially smaller contributor than were changes in saturation factors.

Galbn, Craig J.; Ellis, Scott J.; Spencer, Richard G. S.

2003-04-01

321

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

322

Fracture mode analysis and related surface deformation during dyke intrusion: Results from 2D experimental modelling  

NASA Astrophysics Data System (ADS)

The complex mechanics occurring at tips of dykes during their propagation are very challenging to address in volcanic systems. Direct observation of dyke propagation is impossible, and only indirect geophysical monitoring, such ground deformation induced by dyke emplacement, are available. Interpreting ground deformation in terms of dynamics of dyke emplacement thus requires a full understanding of the fracture mode at dyke tips. To achieve this, we performed 2D laboratory experiments that simulate the emplacement of shallow dykes. Our experimental setup consists of a Hele-Shaw cell, in which model magma is injected into a cohesive model crust. The morphology of the dyke was photographed through time. Using an optical image correlation technique (Particle Imaging Velocimetry), we also measured the surface deformation, the displacements and the strain field induced by the emplacement of the dykes within the country rock. We identify two types of intrusion morphologies (Types A and B), which exhibit two evolutional stages. During the first stage, both types resulted in a vertical dyke at depth; its propagation was controlled by both shear deformation and tensile opening. The model surface lifted up to form a smooth symmetrical dome, resulting in tensile cracks. During the second stage, Types A and B experiments differ when the dyke reaches a critical depth. In Type A, the intrusion gradually rotates, forming an inclined sheet dipping between 45 to 65. This rotation results in asymmetrical surface uplift and shear failure upon the tip of the dyke. In Type B, the dyke tip interacts with tensile cracks formed during the first stage. This fracture controls the subsequent propagation of the dyke toward the surface. In both types of experiments, intrusions result in surface uplift, which can be accommodated by reverse faults. Our study provides important understanding on the mode of propagation of dyke tips and suggests that they propagate as viscous indenters, rather than linear elastic fracturing.

Mansour Abdelmalak, Mohamed; Mourgues, Regis; Galland, Olivier

2013-04-01

323

Experimental and numerical study of cellulose-based electro-active paper energy harvester  

NASA Astrophysics Data System (ADS)

In this present study experimental and finite element analysis of cellulose based electro-active paper energy harvester is presented. Electro-active paper coated with metal electrode is a smart form of cellulose and exhibit piezoelectric effect. Specimens were prepared by depositing electrodes on both sides of the cellulose film. A 50 mm x 50 mm cellulose film coated with aluminum electrodes was bonded on 100 mm x 50 mm x 1 mm aluminum host structure. The voltage output to input acceleration frequency response across a load resistor of 1 M? is recorded by conventional energy harvesting experimental setup at the fundamental vibration mode of the EAPap cantilever beam. A coupled piezoelectric-circuit finite element model is developed in which load resistor is directly connected to energy scavenging device. Voltage output FRF is measured for the cases, without proof mass, and by adding a 2 grams proof mass near the tip of the cantilever. The experimental voltage FRF value is 7.6 V/g at 75.1 Hz and is improved to 13.8 V/g at 62.2 Hz when a stainless steel proof mass of 2 grams is added. The presented CPC-FEM model results agree reasonably well with the experimental results. Despite the fact that the electro-mechanical coupling coefficient of electro-active paper is lower than other available piezoelectric materials, it is biocompatible, cheap and naturally occurring polymeric material. It is also very flexible and posses similar piezoelectric characteristics such a PVDF which inspire to use EAPap in energy harvesting applications.

Abas, Zafar; Kim, Heung Soo; Zhai, Lindong; Kim, Jaehwan

2014-04-01

324

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

325

Single Bloch wall dynamics in amorphous ribbons: A comparison between experimental and theoretical results  

NASA Astrophysics Data System (ADS)

A numerical approach is introduced to study the motion of a single bowed domain wall in an isotropic ferromagnetic lamination under general conditions of time dependence of the exciting magnetic field. A large set of numerical results concerning the behavior of Bloch walls in a magnetostrictive amorphous ribbon (Allied Signal Metglas 2605 SC), submitted to a sinusoidal field of varying amplitude and frequency is reported and discussed. The results are compared with the ones reported in the literature and obtained through different methods of calculation. The present approach allows one to get valuable information on the effect of wall bowing on the magnetic permeability, the so-called magnetic skin effect and the critical field which corresponds to a domain-wall instability resulting in wall multiplication. The peculiar behavior of the phase shift between wall oscillations at the lamination surface and within the lamination bulk appears to be very sensitive to the value of the wall's surface energy density ?w, at least within an appropriate frequency domain, thereby suggesting a reliable method of measuring this quantity. Actual measurements performed on a Metglas 2605 SC ribbon by using a Kerr-effect optical technique are reported and compared with the theoretical predictions. When a tensile stress of about 500 MPa is applied to this highly magnetostrictive material to provide a regular pattern of straight domain walls aligned along the ribbon axis, a value of ?w=1.710-3 J/m2 is found. This value is consistent with the one calculated from the magnetostriction and the exchange energy coefficient of Metglas 2605 SC, which is between 1.410-3 and 1.810-3 J/m2. Measurements of the behavior of the wall oscillation amplitude as a function of the field intensity are also reported and discussed.

Maraner, A.; Beatrice, C.; Mazzetti, P.

1994-04-01

326

Modal characterization of the ASCIE segmented optics testbed: New algorithms and experimental results  

NASA Technical Reports Server (NTRS)

New frequency response measurement procedures, on-line modal tuning techniques, and off-line modal identification algorithms are developed and applied to the modal identification of the Advanced Structures/Controls Integrated Experiment (ASCIE), a generic segmented optics telescope test-bed representative of future complex space structures. The frequency response measurement procedure uses all the actuators simultaneously to excite the structure and all the sensors to measure the structural response so that all the transfer functions are measured simultaneously. Structural responses to sinusoidal excitations are measured and analyzed to calculate spectral responses. The spectral responses in turn are analyzed as the spectral data become available and, which is new, the results are used to maintain high quality measurements. Data acquisition, processing, and checking procedures are fully automated. As the acquisition of the frequency response progresses, an on-line algorithm keeps track of the actuator force distribution that maximizes the structural response to automatically tune to a structural mode when approaching a resonant frequency. This tuning is insensitive to delays, ill-conditioning, and nonproportional damping. Experimental results show that is useful for modal surveys even in high modal density regions. For thorough modeling, a constructive procedure is proposed to identify the dynamics of a complex system from its frequency response with the minimization of a least-squares cost function as a desirable objective. This procedure relies on off-line modal separation algorithms to extract modal information and on least-squares parameter subset optimization to combine the modal results and globally fit the modal parameters to the measured data. The modal separation algorithms resolved modal density of 5 modes/Hz in the ASCIE experiment. They promise to be useful in many challenging applications.

Carrier, Alain C.; Aubrun, Jean-Noel

1993-01-01

327

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

328

Comparison of sound fields generated by different coded excitations--experimental results.  

PubMed

This work reports the results of measurements of spatial distributions of ultrasound fields obtained from five energizing schemes. Three different codes, namely, chirp signal and two sinusoidal sequences were investigated. The sequences were phase modulated with 13 bits Barker code and 16 bits Golay complementary codes. Moreover, two reference signals generated as two and sixteen cycle sine tone bursts were examined. Planar, 50% (fractional) bandwidth, 15 mm diameter source transducer operating at 2 MHz center frequency was used in all measurements. The experimental data were collected using computerized scanning system and recorded using wideband, PVDF membrane hydrophone (Sonora 804). The measured echoes were compressed, so the complete pressure field in the investigated location before and after compression could be compared. In addition to a priori anticipated increase in the signal to noise ratio (SNR) for the decoded pressure fields, the results indicated differences in the pressure amplitude levels, directivity patterns, and the axial distance at which the maximum pressure amplitude was recorded. It was found that the directivity patterns of non-compressed fields exhibited shapes similar to the patterns characteristic for sinusoidal excitation having relatively long time duration. In contrast, the patterns corresponding to compressed fields resembled those produced by brief, wideband pulses. This was particularly visible in the case of binary sequences. The location of the maximum pressure amplitude measured in the 2 MHz field shifted towards the source by 15 mm and 25 mm for Barker code and Golay code, respectively. The results of this work may be applicable in the development of new coded excitation schemes. They could also be helpful in optimizing the design of imaging transducers employed in ultrasound systems designed for coded excitation. Finally, they could shed additional light on the relationship between the spatial field distribution and achievable image quality and in this way facilitate optimization of the images obtained using coded systems. PMID:16313936

Nowicki, A; Klimonda, Z; Lewandowski, M; Litniewski, J; Lewin, P A; Trots, I

2006-01-01

329

Chemical generation of atomic iodine for the chemical oxygeniodine laser. II. Experimental results  

Microsoft Academic Search

A new method for the chemical generation of atomic iodine intended for use in a chemical oxygeniodine laser (COIL) was investigated experimentally. The method is based on the fast reaction of hydrogen iodide with chemically produced chlorine atoms. Effects of the initial ratio of reactants and their mixing in a flow of nitrogen were investigated experimentally and interpreted by means

Otomar palek; V??t Jirsek; Miroslav ?ensk; Jarmila Kodymov; Ivo Jakubec; Gordon D. Hager

2002-01-01

330

One-dimensional combined field and thermionic emission model and comparison with experimental results  

E-print Network

One-dimensional combined field and thermionic emission model and comparison with experimental the entire range of emission from thermionic to field emission, including the mixed emission regime by simultaneously fitting thermionic and field emission data for the cathode. Comparing the experimental

Scharer, John E.

331

The Preliminary Experimental Results of Resonant Magnetic Perturbation Coils on J-TEXT Tokamak  

NASA Astrophysics Data System (ADS)

A set of saddle coils system designed for generating rotating resonant magnetic perturbations (RMPs) has been installed inside the vacuum vessel of the J-TEXT tokamak and recently operated in DC mode and produced mainly m/n=2/1 mode perturbations. This system named as DRMP consists of 12 coils divided into 4 groups which equivalently locate in the toroidal direction. Another set of saddle coils system (now given a new name as SRMP) originally designed for TEXT-U has also been reconstructed outside the J-TEXT vessel wall. The SRMP mainly generates 2/1, 3/1 and some other higher m modes perturbations. In a J-TEXT Ohmic discharge, when the visible tearing modes with a high frequency ( > 6 kHz, typically), the SRMP applied on a suitable spatial phase can suppress the modes completely, but if the SRMP operates at the opposite spatial phase, a locked mode would be stimulated afterward even though the modes have been suppressed. Nevertheless, if the mode frequency is too low, RMP will directly lead to mode locking. With some discharges without any visible tearing modes, mode penetration by DRMP is observed. The experimental results and their possible explanations will be given in the meeting.

Rao, Bo; Ding, Yonghua; Jin, Wei; Hu, Qiming; Wang, Nengchao; Yi, Bin; Li, Quanlin; Zeng, Wubing; Zhuang, Ge

2012-10-01

332

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

333

Experimental Results Obtained with Air Liquide Cold Compression System: CERN LHC and SNS Projects  

NASA Astrophysics Data System (ADS)

Large scale collider facilities will make intensive use of superconducting magnets, operating below 2.0 K. This dictates high-capacity refrigeration systems operating below 2.0 K. These systems, making use of cryogenic centrifugal compressors in a series arrangement with room temperature screw compressors will be coupled to a refrigerator, providing a certain power at 4.5 K. A first Air Liquide Cold Compression System (CCS) unit was built and delivered to CERN in 2001. Installed at the beginning of 2002, it was commissioned and tested successfully during year 2002. A series of four sets of identical CCS were then tested in 2004. Another set of four cryogenic centrifugal compressors (CCC) has been delivered to Thomas Jefferson National Accelerator Facility (JLAB) for the Spallation Neutron Source (SNS) in 2002. These compressors were tested and commissioned from December 2004 to July 2005. The experimental results obtained with these systems will be presented and discussed: the characteristics of the CCC will be detailed. The principles of control for the CCC in series will be detailed.

Delcayre, F.; Courty, J.-C.; Hamber, F.; Hilbert, B.; Monneret, E.; Toia, J.-L.

2006-04-01

334

Contribution to modeling of the reflooding of a severely damaged reactor core using PRELUDE experimental results  

SciTech Connect

In case of accident at a nuclear power plant, water sources may not be available for a long period of time and the core heats up due to the residual power. The reflooding (injection of water into core) may be applied if the availability of safety injection is recovered during accident. If the injection becomes available only in the late phase of accident, water will enter a core configuration that will differ significantly from original rod-bundle geometry. Any attempt to inject water after significant core degradation can lead to further fragmentation of core material. The fragmentation of fuel rods may result in the formation of a 'debris bed'. The typical particle size in a debris bed might reach few millimeters (characteristic length-scale: 1 to 5 mm), i.e., a high permeability porous medium. The French 'Institut de Radioprotection et de Surete Nucleaire' is developing experimental programs (PEARL and PRELUDE) and simulation tools (ICARE-CATHARE and ASTEC) to study and optimize the severe accident management strategy and to assess the probabilities to stop the progress of in-vessel core degradation. It is shown that the quench front exhibits either a ID behaviour or a 2D one, depending on injection rate or bed characteristics. The PRELUDE experiment covers a rather large range of variation of parameters, for which the developed model appears to be quite predictive. (authors)

Bachrata, A.; Fichot, F.; Repetto, G. [Institut de Radioprotection et de Surete Nucleaire IRSN, Cadarache (France); Quintard, M. [Universite de Toulouse, INPT, UPS, IMFT Institut de Mecanique des Fluides de Toulouse, Allee Camille Soula, F-31400 Toulouse (France); CNRS, IMFT, F-31400 Toulouse (France); Fleurot, J. [Institut de Radioprotection et de Surete Nucleaire IRSN, Cadarache (France)

2012-07-01

335

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

336

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). PMID:23019354

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

337

Experimental results performed in the framework of the HIPER European Project  

NASA Astrophysics Data System (ADS)

This paper presents the goals and some of the results of experiments conducted within the Working Package 10 (Fusion Experimental Programme) of the HiPER Project. These experiments concern the study of the physics connected to "Advanced Ignition Schemes", i.e. the Fast Ignition and the Shock Ignition Approaches to Inertial Fusion. Such schemes are aimed at achieving a higher gain, as compared to the classical approach which is used in NIF, as required for future reactors, and making fusion possible with smaller facilities. In particular, a series of experiments related to Fast Ignition were performed at the RAL (UK) and LULI, France) Laboratories and were addressed to study the propagation of fast electrons (created by a short-pulse ultra-high-intensity beam) in compressed matter, created either by cylindrical implosions or by compression of planar targets by (planar) laser-driven shock waves. A more recent experiment was performed at PALS and investigated the laser-plasma coupling in the 1016 W/cm2 intensity regime of interest for Shock Ignition.

Batani, D.; Koenig, M.; Baton, S.; Perez, F.; Gizzi, L. A.; Koester, P.; Labate, L.; Honrubia, J.; Debayle, A.; Santos, J.; Schurtz, G.; Hulin, S.; Ribeyre, X.; Fourment, C.; Nicolai, P.; Vauzour, B.; Gremillet, L.; Nazarov, W.; Pasley, J.; Tallents, G.; Richetta, M.; Lancaster, K.; Spindloe, Ch.; Tolley, M.; Neely, D.; Norreys, P.; Kozlova, M.; Nejdl, J.; Rus, B.; Antonelli, L.; Morace, A.; Volpe, L.,; Davies, J.; Wolowski, J.; Badziak, J.

2011-06-01

338

First Experimental Results with a New Type of Stent: The Double-Coil Device  

SciTech Connect

Purpose: To introduce a new stent design and evaluate its technical properties. Methods: This stent consists of two nitinol wires partially connected to each other.After delivery through a catheter a tube-like helical stent forms within the artery. After experimental tests in flow models regarding mechanical properties, introduction and delivery technique, 15 stents were implanted into iliac, femoral, and carotid arteries of seven dogs.After 3-12 weeks angiographic follow-up stents were explanted for microscopic examination. Results: Stents with expanded diameters of 5-10 mm can be introduced through a 5 Fr catheter with 0.038 inch luminal diameter. Thrombotic vessel occlusion was observed in one iliac artery after incorrect stent placement with diameter mismatch. Fourteen of 15 stents remained patent and revealed minor intimal hyperplasia in the areas of the stent strut connection points as well as some reduction in medial thickness. Conclusion: This new stent design has a small introduction diameter which is independent of the expanded diameter. The stent's principal characteristics may serve as a basis for further special developments.

Strecker, Ernst-Peter [Diakonissenkrankenhaus Karlsruhe, Diakonissenstrasse 28, D-76199 Karlsruhe, Department of Diagnostic Imaging, Interventional Radiology and Nuclear Medicine (Germany)], E-mail: radiologie@diak-ka.de; Song, Ho-Young; Kang, Sung-Gwon [Asan Medical Center, University of Ulsan College of Medicine, Seoul, Department of Diagnostic Radiology (Korea, Republic of); Hou Dongming [Diakonissenkrankenhaus Karlsruhe, Diakonissenstrasse 28, D-76199 Karlsruhe, Department of Diagnostic Imaging, Interventional Radiology and Nuclear Medicine (Germany); Schumacher, M. [University Clinics Freiburg, Freiburg, Institute of Neuroradiology (Germany)

2003-06-15

339

Unsteady pressures on a NACA 64A010 airfoil - Experimental and theoretical results  

NASA Technical Reports Server (NTRS)

Transonic testing of an NACA 64A010 airfoil at the Ohio State University Aero-Astro Research Laboratory is described, and results of fixed angle of attack and pitch oscillation experiments are discussed. The operating range was Mach 0.20 to 1.07 with available total pressures of 140,000 N/m2 to 620,000 N/m2. The airfoil model was mounted on roller bearings installed in the solid sidewalls of the tunnel test section. The equipment included transducers to measure unsteady pressures, and static pressure taps obtaining steady-state data. The data gathered at Mach 0.8 gave an indication of the influence of the natural shock instability and shock-induced flow separation on the unsteady pressures, with the location of the peak disturbance level shifting forward in the comparison of 0 to 2 deg pitch angle data. The oscillating airfoil data is examined in terms of harmonic content and the in-phase and out-of-phase components. It is concluded that the experimental data has good qualitative comparison with methods accounting for shock interaction.

Davis, J. A.; Petrie, S. L.

1979-01-01

340

Patient-cooperative strategies for robot-aided treadmill training: first experimental results.  

PubMed

Task-oriented repetitive movements can improve motor performance in patients with neurological or orthopaedic lesions. The application of robotics and automation technology can serve to assist, enhance, evaluate, and document neurological and orthopedic rehabilitation. This paper deals with the application of "patient-cooperative" techniques to robot-aided gait rehabilitation of neurological disorders. We define patient-cooperative to mean that, during movement, the technical system takes into account the patient's intention and voluntary efforts rather than imposing any predefined movements or inflexible strategies. It is hypothesized that such cooperative robotic approaches can improve the therapeutic outcome compared to classical rehabilitation strategies. New cooperative strategies are presented that detect the patient's voluntary efforts. First, this enables the patient increased freedom of movement by a certain amount of robot compliance. Second, the robot behavior adapts to the existing voluntary motor abilities. And third, the robotic system displays and improves the patient contribution by visual biofeedback. Initial experimental results are presented to evaluate the basic principle and technical function of proposed approaches. Further improvements of the technical design and additional clinical testing is required to prove whether the therapeutic outcome can be enhanced by such cooperative strategies. PMID:16200761

Riener, Robert; Lnenburger, Lars; Jezernik, Saso; Anderschitz, Martin; Colombo, Gery; Dietz, Volker

2005-09-01

341

Experimental results from the HERO project - In situ measurements of ionospheric modifications using sounding rockets  

NASA Astrophysics Data System (ADS)

The HEating ROcket project HERO comprised the first in situ experiments to measure artificial ionospheric modifications at F layer heights set up by radio waves transmitted from the Heating facility at Ramfjord near Tromso in northern Norway. Four instrumented payloads were launched on sounding rockets from Andoya Rocket Range during the autumn of 1982 into a sunlit ionosphere with the sun close to the horizon. The payloads recorded modifications, in particular, the presence of electron plasma waves near the reflection level of the heating wave. The amplitude and phase of the three components of the electric and magnetic fields of the heating wave were measured simultaneously as a function of altitude. Coherent spectra of the three electric field components of the locally generated electron plasma waves were obtained in a 50-kHz-wide band. At the same time quasi-continuous measurements were made on several fixed frequencies from 4 kHz to 16 kHz below the heating frequency and in the VLF-range using linear dipole antennas. Moreover, measurements were made of electron temperature, suprathermal electrons, and local electron density along the rocket trajectory. The experimental results are presented and discussed.

Rose, G.; Grandal, B.; Neske, E.; Ott, W.; Spenner, K.; Holtet, J.; Maseide, K.; Troim, J.

1985-03-01

342

Joint computational/experimental aerodynamics research on a reentry vehicle: Part 2, Computational results  

SciTech Connect

Computational aerodynamics simulation applied to supersonic and hypersonic flight vehicles has significantly increased during the last several years. Flow field simulations have been computed for a wide variety of vehicles from ballistic reentry vehicles to the Space Shuttle. Although computational aerodynamics simulation has been taking more responsibility during this time, wind tunnel experimentation has continued to play the major role in flight vehicle analysis and design. This role, however, is changing because of the great strides in the capability and confidence in numerical simulations. In this paper computational results are obtained for a spherically blunted cone with a slice parallel to the cone axis. Aerodynamic force and moment predictions from Sandia's CFD codes are compared with wind tunnel data from the Sandia Mach 8 hypersonic wind tunnel. These comparisons are made on a sliced reentry vehicle both with and without a windward flap. The windward flap will be deflected 10{degree}, 20{degree}, and 30{degree}. Inviscid/boundary layer codes and the Parabolized Navier-Stokes code are used to generate solutions for the sliced vehicle. In the region of the flap, some reversed flow is apparent and a full Navier-Stokes code will be used to provide comparisons with the data. Force and moment and surface flow visualization comparisons are made for laminar, ideal gas flow. This will be the first of a series of papers providing comparisons with the Sandia wind tunnel data. Additional papers will report comparisons with surface pressure measurements. 21 refs., 9 figs., 1 tab.

Walker, M.M.; Oberkampf, W.L.

1990-01-01

343

Experimental Results From a 2kW Brayton Power Conversion Unit  

NASA Astrophysics Data System (ADS)

This paper presents experimental test results from operation of a 2 kWe Brayton power conversion unit. The Brayton converter was developed for a solar dynamic power system flight experiment planned for the Mir Space Station in 1997. The flight experiment was cancelled, but the converter was tested at Glenn Research Center as part of the Solar Dynamic Ground Test Demonstration system which included a solar concentrator, heat receiver, and space radiator. In preparation for the current testing, the heat receiver was removed and replaced with an electrical resistance heater, simulating the thermal input of a steady-state nuclear source. The converter was operated over a full range of thermal input power levels and rotor speeds to generate an overall performance map. The converter unit will serve as the centerpiece of a Nuclear Electric Propulsion Testbed at Glenn. Future potential uses for the Testbed include high voltage electrical controller development, integrated electric thruster testing and advanced radiator demonstration testing to help guide high power Brayton technology development for Nuclear Electric Propulsion (NEP).

Hervol, David; Mason, Lee; Birchenough, Arthur

2003-01-01

344

Experimental Results from a 2 kW Brayton Power Conversion Unit  

NASA Astrophysics Data System (ADS)

This paper presents experimental test results from operation of a 2 kWe Brayton power conversion unit. The Brayton converter was developed for a solar dynamic power system flight experiment planned for the Mir Space Station in 1997. The flight experiment was cancelled, but the converter was tested at Glenn Research Center as part of the Solar Dynamic Ground Test Demonstration system which included a solar concentrator, heat receiver, and space radiator. In preparation for the current testing, the heat receiver was removed and replaced with an electrical resistance heater, simulating the thermal input of a steady-state nuclear source. The converter was operated over a full range of thermal input power levels and rotor speeds to generate an overall performance map. The converter unit will serve as the centerpiece of a Nuclear Electric Propulsion Testbed at Glenn. Future potential uses for the Testbed include high voltage electrical controller development, integrated electric thruster testing and advanced radiator demonstration testing to help guide high power Brayton technology development for NEP.

Hervol, David; Mason, Lee; Birchenough, Arthur

2003-01-01

345

Storage-and-release flux rope eruptions in the laboratory: initial results and experimental plans  

NASA Astrophysics Data System (ADS)

Solar eruptive events such as coronal mass ejections (CMEs) are thought to be driven by a sudden release of magnetic energy stored in the corona. In many cases, the pre-eruptive configuration is a non-potential magnetic structure that can be modeled as a line-tied magnetic flux rope. In spite of ever-improving observational capabilities, directly studying the evolution of coronal flux ropes remains a significant challenge. Thus, in order to further explore the mechanisms that drive solar eruptions, we must find novel ways to simulate the relevant physical system. To this end, we have constructed a new laboratory experiment to study storage-and-release flux rope eruptions. This experiment contains a carefully designed set of ``sub-photospheric" coils that produces an active-region-like potential field configuration that remains static throughout the discharge. An arched magnetic flux rope plasma is formed within this potential field configuration by driving electric current through two line-tied footpoints (copper electrodes). Over the course of the discharge, the plasma current is quasi-statically increased (to tens of kiloamperes over many Alfvn times) in order to slowly build up magnetic energy in the system. As the flux rope gains energy, it will expand away from the electrodes to a point where it is expected to undergo a dynamic eruption due to the onset of a loss-of-equilibrium [Forbes & Isenberg, Astrophys. J. 373, 294 (1991)] or the torus instability [Kliem & Trk, Phys. Rev. Lett. 96, 255002 (2006)]. In these experiments, the structure of the background potential field configuration (i.e., the field decay index) can be varied to study its effect on the observed flux rope eruptions. Initial results from these experiment are presented, including images from a fast visible light camera and direct measurements from internal magnetic diagnostics. This research is supported by DoE Contract Number DE-AC02-09CH11466 and by the Center for Magnetic Self-Organization (CMSO).; Specially designed magnetic field coils (orange and blue) are used to produce an active-region-like potential field configuration within the vacuum vessel (gray). An arched magnetic flux rope plasma is formed by driving electric current along low-lying potential field lines (blue/green). As magnetic energy builds up in the flux rope, it will expand outward and possibly undergo a storage-and-release eruption.

Myers, C. E.; Yamada, M.; Ji, H.; Yoo, J.; Jara-Almonte, J.; Lawrence, E. E.

2012-12-01

346

Optical properties of linear parabolic concentrators of large area Experimental results  

NASA Astrophysics Data System (ADS)

A parabolic trough solar concentrator with a 2.5-m aperture has been developed which may be used with both a thermodynamic receiver and a photovoltaic array. The present paper presents results of the measurement of the optical properties of the modular concentrator, which limit its performance in photovoltaic applications. The concentration of the collected energy in the focal zone was monitored by the use of a laser beam to illuminate sections of the trough reflecting surface at various angles of incidence and collector inclinations. A new concentration factor defined as the product of the geometric concentration factor with the cosine of the incidence angle at which the radiation strikes the photocell array was then determined for various sections of the trough as a function of trough aperture. These tests have allowed the definition of the size and shape of a prototype photovoltaic converter currently under construction.

Bellecci, C.; Bonanno, A.; Camarca, M.; Conti, M.; Garofalo, G.; Racalbuto, S.; Visentin, R.

1981-06-01

347

Active Piezoelectric Energy Harvesting: General Principle and Experimental Demonstration  

Microsoft Academic Search

In piezoelectric energy harvesting systems, the energy harvesting circuit is the interface between a piezoelectric device and an electrical load. A conventional view of this interface is based on impedance matching concepts. In fact, an energy harvesting circuit can also apply electrical boundary conditions, such as voltage and charge, to the piezoelectric device for each energy conversion cycle. An optimized

Yiming Liu; Geng Tian; Yong Wang; Junhong Lin; Qiming Zhang; Heath F. Hofmann

2009-01-01

348

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

349

Experimental Study of High-Energy Processing of Protoplanetary Materials  

NASA Astrophysics Data System (ADS)

The metal-silicate fractionation in celestial bodies effectively separates siderophile 182W from lithophile 182Hf into the core and mantle, respectively, making the Hf-W chronometer ideal for dating core-formation in differentiated planetary bodies. It is generally believed that there was equilibration of the Hf-W system during primary metal-silicate fractionation of small, initially chondritic, parent bodies. However, the accretion of larger objects like Moon and terrestrial planets generally involves giant impacts, with both the target and projectile probably being differentiated. Then, use of the Hf-W system assumes metal-silicate re-equilibration at high T and P while metal droplets rain through the magma ocean of a growing planet. Currently no experimental data at such conditions exist. Here we report the first results of experiments aimed at studying partitioning of Fe and Ni (proxy for W) between metal and silicate melt formed at high P and T by laser shocks of powered mixtures of pure Fe metal and Ni-bearing ALM-2 dunite. The initial targets with variable metal/dunite ratios were lightly pressed into 6.3 mm pellets (1-3 mm thick) and subjected to single laser pulses (~120-600 J, ~1 nsec). The details of experiments are described in the accompanying abstract by Remo et al. Some shots produced ~ 1 mm round craters in partially preserved targets which have been studied by optical microscopy, SEM and EPMA. The craters have rather rough surfaces and blackened appearance. The SEM images show thin (1-3 microns) films or pockets (3-8 microns) of silicate melt with or without tiny metal blebs which weld together angular grains of olivine and metal. The olivine contains no Al2O3 and ~0.4 wt% NiO; the metal is pure Fe. The melt, besides being lighter in the BSE images, shows distinct compositional differences (higher Al2O3 and FeO, lower MgO and SiO2) from olivine. The NiO content in metal-free melt films and pockets is similar to that in the host olivine. Metal in the metal-bearing melt pockets typically contains 0.2-0.7 wt% Ni and 0.6-1.5 wt% Si, while the NiO content in the silicate melt is close or below the EPMA detection limit of ~0.05 wt%. Thus, our results provide clear evidence for rapid extraction of Ni from silicate melt into metal on a timescale of microseconds. Chemical analyses and further experimental details will be reported at the meeting.

Petaev, M. I.; Jacobsen, S. B.; Remo, J. L.; Adams, R. G.; Sasselov, D. D.

2006-12-01

350

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

351

Computational modeling of stationary gastungsten-arc weld pools and comparison to stainless steel 304 experimental results  

Microsoft Academic Search

A systematic study was carried out to verify the predictions of a transient multidimensional computational model by comparing\\u000a the numerical results with the results of an experimental study. The welding parameters were chosen such that the predictions\\u000a of the model could be correlated with the results of an earlier experimental investigation of the weld pool surface temperatures\\u000a during spot gas-tungsten-arc

T. Zacharia; S. A. David; J. M. Vitek; H. G. Kraus

1991-01-01

352

Experimental study of the flow regimes resulting from the impact of an intermittent gasoline spray  

NASA Astrophysics Data System (ADS)

The present paper reports a complete set of measurements made with a two-component phase Doppler anemometer of the two-phase flow generated at the impact of a transient gasoline spray onto a flat surface. The spray is generated by a pintle injector and the fuel used was gasoline. The measurements of droplet size velocity were processed to provide time fluxes of number, mass, normal momentum, and energy of the poly-dispersion of droplets ejected at impact, and analyzed based on predictive tools available in the literature. The results show that splash is the dominant mechanism by which secondary droplets are ejected from the surface, either in the stagnation region or in the core region of the spray. In the stagnation region, a large fraction of each incident droplet adheres to the surface and the axial incident momentum contributes with a larger parcel than tangential momentum. As a result, the normal velocity of ejected droplets is much smaller than that of the original incident droplets, while tangential velocity is enhanced. The region near the stagnation point is immediately flooded upon impact of the leading front of the spray, forming a liquid film that is forced to move radially outwards as droplets continue to impinge during the steady period. Spray/wall interaction in the core region thus occurs in the presence of a moving thin liquid film, which enhances transfer of tangential momentum. As a result, film spreading and dynamics as a result of impingement forces are crucial to accurate model spray/wall interaction. The outer region of the spray is dominated by the vortical structure induced by shear forces, which entrains small responsive secondary droplets to re-impinge. Furthermore, prediction of the outcome of spray impact requires a precise knowledge of the two-phase flow in the presence of the target.

Pano, M. R. O.; Moreira, A. L. N.

2004-12-01

353

Data processing and display of laser Doppler experimental results, volume 1  

NASA Technical Reports Server (NTRS)

Contract activities performed in developing a laser Doppler system for detecting, tracking, and measuring aircraft wake vortices are summarized. The computer program for processing and displaying the Dust Devil experimental data is presented. Program listings are included in the appendix.

Ashmore, B. R.; Kimura, A.; Skeith, R. W.

1976-01-01

354

Investigation of the Acoustic Properties of Supersonic Jets with Fluidic Injection on Chevrons: Experimental Results  

Microsoft Academic Search

An experimental investigation of two jet noise reduction techniques is presented. These techniques are currently employed on commercial aircraft, and we now apply them to a convergent-divergent nozzle with geometry typical of military aircraft. The acoustic effects of chevrons and fluidic injection on chevrons are quantified by Near-Field and Far-Field acoustic measurements. Experimental tests are shown for overexpanded, underexpanded, and

David Munday; Nick Heeb; Ephraim Gutmark; Junhui Liu; K. Kailasanath

2009-01-01

355

Electrical conductivity of olivine: New experimental results and a unified model for hydrogen-assisted conduction  

NASA Astrophysics Data System (ADS)

Although extensive experimental studies have been carried out on the hydrogen-assisted electrical conductivity in olivine, a few important issues remain unclear. We have conducted new experiments (i) on the pressure effects, (ii) on the influence of Fe content, and (iii) on the influence of oxygen fugacity on hydrogen-assisted conductivity to clarify these issues. The pressure effect is important in resolving the difference between Wang et al. (2006) and Yoshino et al. (2009) and also in evaluating the conductivity jump at the 410-km discontinuity. Our new results show only a small effect of pressure indicating that (i) the difference between Wang et al. (2006) and Yoshino et al. (2009) is not due to the pressure effect, and that (ii) there must be a large drop in conductivity at 410-km boundary if the water content in the upper mantle is the same as that of the transition zone. We also conducted a series of experiments to determine the influence of Fe on hydrogen-assisted conductivity. Both Fe and hydrogen enhance conductivity, but their combined effect was not characterized. We found that Fe effect and hydrogen effect are connected: for given hydrogen content, conductivity is higher for a sample with higher Fe content. This implies that the hydrogen mobility is enhanced by Fe. The results have potential applications for Fe-rich planets such as Mars. We are also conducting a series of experiments to see the influence of oxygen fugacity on hydrogen-assisted conductivity. A similar study was made for wadsleyite showing the negative dependence of conductivity on oxygen fugacity showing a simple model of hydrogen-assisted conductivity (i.e., all hydrogen atoms contribute equally to conductivity) does not work. Our new results will provide strong constraints on the mechanism of hydrogen-assisted conduction in olivine. A hybrid model explains a broad range of observations including the discrepancies between diffusion data and electrical conductivity, and predicts that hydrogen-assisted conductivity will be highly anisotropic at high temperatures.

Karato, S.; Dai, L.

2013-12-01

356

Results from the STAR Beam Energy Scan Program  

E-print Network

The main aim of the beam energy scan (BES) program at the Relativistic Heavy-Ion Collider (RHIC) is to explore the quantum chromodynamics (QCD) phase diagram. The specific physics goal is to search for the phase boundary and the QCD critical point. We present results from Au+Au collisions at various energies collected in the BES program by the Solenoidal Tracker At RHIC (STAR) experiment. First results on transverse momentum ($p_{T}$) spectra, $dN/dy$, and average transverse mass ($$) for identified hadrons produced at mid-rapidity for $\\sqrt{s_{NN}}$ = 7.7 GeV are presented. Centrality dependence of $dN/dy$ and $$ are also discussed and compared to corresponding data from other energies. In addition, first results on charged hadron directed ($v_{1}$) and elliptic flow ($v_{2}$) for $\\sqrt{s_{NN}}=$ 7.7, 11.5, and 39 GeV are presented. New results on event-by-event fluctuations (particle ratio, net-proton and net-charge higher moments) are presented for $\\sqrt{s_{NN}}=$ 39 GeV.

Lokesh Kumar; for the STAR Collaboration

2011-01-22

357

Macrofauna and nutrient cycling in the Swan River Estuary, Western Australia: experimental results  

NASA Astrophysics Data System (ADS)

This study investigated the effect of benthic macrofauna on nutrient fluxes. The influence of the macrofauna on nutrients released from the sediments was investigated experimentally in the laboratory using sediment cores from the Swan-Canning Estuary. Excretion rates of common benthic species were also measured to quantify the role of the macrofauna in estuarine nutrient cycling.The presence of macrofauna increased the release of phosphate and ammonium into the water column but decreased the release, or resulted in uptake, of nitrate by the sediments. There were no significant differences in porewater concentrations of ammonium, nitrate or phosphate between treatments with and without macrofauna. The macrofauna clearly had an important role in nutrient fluxes, as nutrient release differed between cores with and without fauna, and nutrient fluxes were significantly correlated with increased faunal biomass.Other factors, such as season and dissolved oxygen concentrations, influenced the concentration of nutrients released. Ammonium was released into the overlying water column at higher rates in winter than summer, while nitrate was released at higher rates in summer than winter. Aeration did not have a significant effect on nutrient fluxes, however there was a significant increase in filterable reactive phosphorus, and decrease in nitrate, in the porewater of cores which were not aerated.Benthic species excreted phosphate, nitrate and ammonium, with ammonium present in the largest amounts. Comparison of excretion rates to the amount of nutrients released into the water column in the core experiments revealed that excretion could account for 30% of the phosphate and >200% of the ammonium measured in the water column.Clearly the benthic macrofauna have a significant role with respect to benthic nutrient fluxes within the Swan-Canning Estuary, with benthic regeneration of nutrients estimated to equal external loading of nutrients. However, further work is required to more precisely define the influence of seasonality, dissolved oxygen, microbial activity and sediment characteristics on nutrient fluxes.

Pennifold, Melita; Davis, Jenny

2001-09-01

358

Experimental critical loadings and control rod worths in LWR-PROTEUS configurations compared with MCNPX results  

SciTech Connect

The PROTEUS research reactor at the Paul Scherrer Inst. (PSI) has been operating since the sixties and has already permitted, due to its high flexibility, investigation of a large range of very different nuclear systems. Currently, the ongoing experimental programme is called LWR-PROTEUS. This programme was started in 1997 and concerns large-scale investigations of advanced light water reactors (LWR) fuels. Until now, the different LWR-PROTEUS phases have permitted to study more than fifteen different configurations, each of them having to be demonstrated to be operationally safe, in particular, for the Swiss safety authorities. In this context, recent developments of the PSI computer capabilities have made possible the use of full-scale SD-heterogeneous MCNPX models to calculate accurately different safety related parameters (e.g. the critical driver loading and the shutdown rod worth). The current paper presents the MCNPX predictions of these operational characteristics for seven different LWR-PROTEUS configurations using a large number of nuclear data libraries. More specifically, this significant benchmarking exercise is based on the ENDF/B6v2, ENDF/B6v8, JEF2.2, JEFF3.0, JENDL3.2, and JENDL3.3 libraries. The results highlight certain library specific trends in the prediction of the multiplication factor k{sub eff} (e.g. the systematically larger reactivity calculated with JEF2.2 and the smaller reactivity associated with JEFF3.0). They also confirm the satisfactory determination of reactivity variations by all calculational schemes, for instance, due to the introduction of a safety rod pair, these calculations having been compared with experiments. (authors)

Plaschy, M.; Murphy, M.; Jatuff, F.; Seiler, R. [Paul Scherrer Institut PSI, CH-5232 Villigen PSI (Switzerland); Chawla, R. [Paul Scherrer Institut PSI, CH-5232 Villigen PSI (Switzerland); Ecole Polytechnique Federale de Lausanne EPFL, CH-1015 Lausanne (Switzerland)

2006-07-01

359

Slit-scanning differential phase-contrast mammography: first experimental results  

NASA Astrophysics Data System (ADS)

The demands for a large field-of-view (FOV) and the stringent requirements for a stable acquisition geometry rank among the major obstacles for the translation of grating-based, differential phase-contrast techniques from the laboratory to clinical applications. While for state-of-the-art Full-Field-Digital Mammography (FFDM) FOVs of 24 cm x 30 cm are common practice, the specifications for mechanical stability are naturally derived from the detector pixel size which ranges between 50 and 100 ?m. However, in grating-based, phasecontrast imaging, the relative placement of the gratings in the interferometer must be guaranteed to within micro-meter precision. In this work we report on first experimental results on a phase-contrast x-ray imaging system based on the Philips MicroDose L30 mammography unit. With the proposed approach we achieve a FOV of about 65 mm x 175 mm by the use of the slit-scanning technique. The demand for mechanical stability on a micrometer scale was relaxed by the specific interferometer design, i.e., a rigid, actuator-free mount of the phase-grating G1 with respect to the analyzer-grating G2 onto a common steel frame. The image acquisition and formation processes are described and first phase-contrast images of a test object are presented. A brief discussion of the shortcomings of the current approach is given, including the level of remaining image artifacts and the relatively inefficient usage of the total available x-ray source output.

Roessl, Ewald; Daerr, Heiner; Koehler, Thomas; Martens, Gerhard; van Stevendaal, Udo

2014-03-01

360

Experimental results from containment piping bellows subjected to severe accident conditions: Results from bellows tested in corroded conditions. Volume 2  

SciTech Connect

Bellows are an integral part of the containment pressure boundary in nuclear power plants. They are used at piping penetrations to allow relative movement between piping and the containment wall, while minimizing the load imposed on the piping and wall. Piping bellows are primarily used in steel containments; however, they have received limited use in some concrete (reinforced and prestressed) containments. In a severe accident they may be subjected to pressure and temperature conditions that exceed the design values, along with a combination of axial and lateral deflections. A test program to determine the leak-tight capacity of containment penetration bellows is being conducted at Sandia National Laboratories under the sponsorship of the US Nuclear Regulatory Commission. Several different bellows geometries, representative of actual containment bellows, have been subjected to extreme deflections along with pressure and temperature loads. The bellows geometries and loading conditions are described along with the testing apparatus and procedures. A total of nineteen bellows have been tested. Thirteen bellows were tested in ``like-new`` condition (results reported in Volume 1), and six were tested in a corroded condition. The tests showed that bellows in ``like-new`` condition are capable of withstanding relatively large deformations, up to, or near, the point of full compression or elongation, before developing leakage, while those in a corroded condition did not perform as well, depending on the amount of corrosion. The corroded bellows test program and results are presented in this report.

Lambert, L.D.; Parks, M.B. [Sandia National Labs., Albuquerque, NM (United States)

1995-10-01

361

OPERA, MINOS Experimental Result Prove Special and General Relativity Theories; the Principle of Lorentz Invariance Invalid  

NASA Astrophysics Data System (ADS)

A great discrepancy exists - the speed of light and the neutrino speed must be identical; as indicated by supernova1987A; yet, OPERA predicts faster-than-light neutrinos. Einstein's theories are based on the invariance of the speed of light, and no privileged Galilean frame of reference exists. Both of these hypotheses are in error and must be reconciled in order to solve the dilemma. The Michelson-Morley Experiment was misinterpreted - my Neoclassical Theory postulates that BOTH mirrors of the interferometer physically and absolutely move towards its center. The result is a three-directional-Contraction, (x, y, z axis), an actual distortion of space itself; a C-Space condition. ``PRESSLER'S LAW OF C-SPACE: The speed of light, c, will always be measured the same speed in all three directions (300,000 km/sec), in ones own inertial reference system, and will always be measured as having a different speed in all other inertial frames which are at a different kinetic energy level or at a location with a different strength gravity field'' Thus, the faster you go, motion, or the stronger the gravity field the smaller you get in all three directions. OPERA results are explained; at the surface of Earth, the strength of gravity field is at maximum -- below the earth's surface, time and space is less distorted; therefore, time is absolutely faster accordingly. Reference OPERA's preprint: Neutrino's faster time-effect due to altitude difference; (10-13ns) x c (299792458m) = 2.9 x 10-5 m/ns x distance (730085m) + 21.8m.) This is consistent with the OPERA result.

Pressler, David E.

2012-03-01

362

Selected Results from STAR Beam Energy Scan Program  

E-print Network

Results from the Beam Energy Scan (BES) program conducted by STAR experiment at RHIC are presented. The data from Phase-I of the BES program collected in Au+Au collisions at center-of-mass energies ($\\sqrt{s_{NN}}$) of 7.7, 11.5, 19.6, 27, and 39 GeV cover a wide range of baryon chemical potential $\\mu_{B}$ (100--400 MeV) in the QCD phase diagram. Several STAR results from the BES Phase-I related to "turn-off" of strongly interacting quark--gluon plasma (sQGP) signatures and signals of QCD phase boundary are reported. In addition to this, an outlook is presented for the future BES Phase-II program and a possible fixed target program at STAR.

Michal umbera for the STAR Collboration

2013-12-10

363

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

364

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

365

Recent theoretical and experimental results of high-current transport studies at the University of Maryland and GSI  

SciTech Connect

In this paper recent simulation studies at GSI on instabilities and emittance growth for different particle distributions and initial experimental results with the 12-lens section of the University of Maryland electron beam transport channel are reviewed.

Reiser, M.

1984-01-01

366

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 (0.81.0)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

367

A comparison of experimental and theoretical results for leakage, pressure gradient, and rotordynamic coefficients for tapered annular gas seals  

E-print Network

A COMPARISON OF EXPERIMENTAL AND THEORETICAL RESULTS FOR LEAKAGE, PRESSURE GRADIENT, AND ROTORDYNAMIC COEFFICIENTS FOR TAPERED ANNULAR GAS SEALS A Thesis by DAVID ALAN ELROD Submitted to the Graduate College of Texas A&M University... in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE December 1986 Major Subject: Mechanical Engineering A COMPARISON OF EXPERIMENTAL AND THEORETICAL RESULTS FOR LEAKAGE, PRESSURE GRADIENT, AND ROTORDYNAMIC COEFFICIENTS...

Elrod, David Alan

2012-06-07

368

Understanding how hydrodynamics affects particle transport in saturated fractures using modelling and experimental results  

NASA Astrophysics Data System (ADS)

Approximately 35% of Canadians and Americans utilize groundwater for drinking water and as such, it is essential to understand the mechanisms which may jeopardize this resource. Porous media aquifers typically provide significant removal of particulate contaminants (eg. viruses, bacteria); however, fractures in fractured rock aquifers and aquitards often provide pathways for particles to move in greater numbers and speed than in porous media. Thus, understanding flow and transport in fractures is important for the preservation and use of groundwater sources. Models based on coupling flow and transport equations can be used in understanding transport in fractures. Both experiments and simulations have shown that there are inconsistencies in current transport, attachment and detachment theory, particularly when particle size is varied. The assumption that hydrodynamic effects do not significantly affect transport of particles is likely untrue. As well, it has been shown that preferential flow paths occur in fractures, but the effects of path specific properties such as fracture geometry have yet to be thoroughly explored. It has been observed that eddies caused by local changes in geometry exist in fractures in the environment and models have demonstrated that such eddies will retard the flow of particles. In this work, two 2D fractures were randomly generated with a mean aperture of approximately 2mm. Finite element software, COMSOL Multiphysics, generated flow fields through the fractures by numerically solving the steady-state Navier-Stokes equation for varied flow rates. Eddies were observed in one of the fractures at both low (~1 m/day) and high (>100 m/day) velocities. A program was written using random walk particle tracking to simulate transport. Theories of attachment, detachment and matrix flow are not included in this model in order to isolate hydrodynamic forces. In combination with the modelling procedure, the two fractures were inscribed into pieces of poly(methyl methacrylate), thus creating a pseudo-2D fracture. Namely, the 2D fracture (x-y coordinates) is cut into the plastic using a laser printer, thus the z-coordinate is constant to a depth of 2.3 mm. Experiments using Acid Yellow 17, as a tracer, as well as fluorescent microspheres (42.5 nm and 525 nm, non-carboxylated to minimize attachment/detachment) will be performed in order to compare simulations and experimental results. Concentrations of the microspheres and tracer were measured at the effluent end of the fracture where the end cap housed an LED (400-470 nm) and an optical fibre attached to a spectrophotometer. Simulations suggest that in fractures where eddies occur, there is retention of smaller particles only when there is sufficient diffusion and a slow enough fluid velocity to allow them to enter the eddy. Otherwise, the particles exit the fracture earlier than typically expected when considering particle size exclusion and average fluid velocity. Further modelling results suggest that using bulk measurements (eg. mean aperture, mean fluid velocity, and measures of fracture roughness) to predict the resultant particulate outflow in a saturated fracture is difficult. We plan to include visualization experiments in order to draw further comparisons to the modelling results.

Cianflone, S.; Lakhian, V.; Dickson, S. E.

2013-12-01

369

Experimental determination of the solubility of iridium in silicate melts: Preliminary results  

NASA Technical Reports Server (NTRS)

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

1992-01-01

370

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

371

EXPERIMENTAL RESULTS OF A MESOSCALE ELECTRIC POWER GENERATION SYSTEM FROM PRESSURIZED GAS FLOW  

Microsoft Academic Search

In many process applications, where a pressure reduction is required, the energy is 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 density

D. Krhenbhl; C. Zwyssig; H. Weser; J. W. Kolar

372

Variation of Pneumococcal Pilus-1 Expression Results in Vaccine Escape during Experimental Otitis Media [EOM  

PubMed Central

The pneumococcal Pilus-1 enhances attachment to epithelial cells in the respiratory tract and subsequent invasion. Pilus-1 expression is bi-stable and positively regulated by the RlrA transcriptional regulator. To delineate the role of pilus-1 in Experimental Otitis Media (EOM), we evaluated colonization and disease due to a Streptococcus pneumoniae (SP) wild type strain (Taiwan19F-14 wt) and its otherwise isogenic pilus-1 and pilus-2 deficient mutant (Taiwan19F-14 ?PI-1/PI-2-) as well as potential for a chimeric protein (RrgB321) vaccine candidate for prevention of middle ear (ME) disease. Methods Chinchillas were challenged intranasally with either Taiwan19F-14 wt or Taiwan19F-14PI-1/PI-2 deficient mutant. ME status was assessed and direct cultures performed. New cohorts of animals were immunized with RrgB321 or alum. Intranasal challenge with Taiwan19F-14 wt [erythromycin susceptible E(S)] was performed. Subsequently, a second cohort of animals was immunized and challenged with either Taiwan19F-14 wt or a Pilus-1 over-expressing mutant [Taiwan19F-14+pMU1328_Pc-rlrA mutant; E resistant (R)] strain. Pilus-1 expression was analyzed in SP isolated from nasopharynx (NP) and ME fluids by flow cytometry. Results Culture positive EOM developed following challenge with either wild type SP (Taiwan19F-14) or its pilus-1 deficient mutant. Culture positive EOM developed following challenge with wild type in both RrgB321 immunized and control animals. Pilus-1 expression in ME fluids was significantly higher in controls compared to immunized chinchillas. In second cohort of immunized and control animals challenged with the over-expressing Pilus-1 mutant, delayed development of EOM in the immunized animals was observed. Pneumococci recovered from ME fluid of immunized animals were no longer E(R) signifying the loss of the pMU1328_Pc-rlrA plasmid. Conclusion Pneumococcal pilus-1 was not essential for EOM. Regulation of Pilus-1 expression in ME fluids in the presence of anti RrgB321 antibody was essential for survival of S. pneumoniae. Pneumococci have evolved mechanisms of regulation of non-essential surface proteins to evade host defenses. PMID:24421906

Figueira, Marisol; Moschioni, Monica; De Angelis, Gabriella; Barocchi, Michele; Sabharwal, Vishakha; Masignani, Vega; Pelton, Stephen I.

2014-01-01

373

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

374

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

375

Results of Stocking Largemouth Black Bass and Channel Catfish in Experimental Texas Farm Ponds  

Microsoft Academic Search

Twenty-two experimental farm ponds were operated at the A. E. Wood State Fish Hatchery, San Marcos, Texas, during the period 194850. Various stocking ratios and species combinations were employed for both fry and fingerlings of largemouth black bass (Micropterus salmoides) and fingerling channel catfish (Ictalurus lacustris). Forage fish including bluegill (Lepomis macrochirus), redear (Lepomis microlophus), and yellowbelly (Lepomis auritus) sunfish

William H. Brown

1951-01-01

376

Comparison of numerical and experimental results of the flow in the U9 Kaplan turbine model  

Microsoft Academic Search

The present work compares simulations made using the OpenFOAM CFD code with experimental measurements of the flow in the U9 Kaplan turbine model. Comparisons of the velocity profiles in the spiral casing and in the draft tube are presented. The U9 Kaplan turbine prototype located in Porjus and its model, located in lvkarleby, Sweden, have curved inlet pipes that lead

O. Petit; B. Mulu; H. Nilsson; M. Cervantes

2010-01-01

377

Catalytic combustion in a reactor with periodic flow reversal. Part 1. Experimental results  

Microsoft Academic Search

The use of a reactor with periodic flow reversal for catalytic incineration of the model pollutants carbon monoxide and propane has been experimentally studied. The mean axial temperature profile over one period in cycle steady state is a symmetrical curve which can be linearised and subdivided into three regions. The center of reactor with a constant maximum temperature and two

H. Zfle; T. Turek

1997-01-01

378

Fracture of Brittle Solids. III. Experimental Results on the Distribution of Fragment Size in Single Fracture  

Microsoft Academic Search

In papers I and II of this series, it was concluded on the basis of theory and a limited number of experimental samples that the over-all differential probability p? of single fracture, as a function of the mean fragment dimension x, should show the presence of three peaks. These correspond to the effect of internal flaws of facial and volume

J. J. Gilvarry; B. H. Bergstrom

1962-01-01

379

Design of a micromachined thermal accelerometer: thermal simulation and experimental results  

Microsoft Academic Search

This paper describes numerical simulation of a micromachined thermal accelerometer and experimental measurements. The sensor principle consists of a heating resistor, which creates a symmetrical temperature profile, and two temperature detectors symmetrically placed on both sides of the heater. When an acceleration is applied, the free convection is modified, the temperature profile becomes asymmetric and the two detectors measure the

F. Mailly; A. Martinez; A. Giani; F. Pascal-delannoy; A. Boyer

2003-01-01

380

Syntactic\\/semantic interactions in programmer behavior: A model and experimental results  

Microsoft Academic Search

This paper presents a cognitive framework for describing behaviors involved in program composition, comprehension, debugging, modification, and the acquisition of new programming concepts, skills, and knowledge. An information processing model is presented which includes a long-term store of semantic and syntactic knowledge, and a working memory in which problem solutions are constructed. New experimental evidence is presented to support the

Ben Shneiderman; Richard Mayer

1979-01-01

381

Event-Based GUI Testing and Reliability Assessment Techniques An Experimental Insight and Preliminary Results  

E-print Network

that graphical user interfaces (GUIs) highly affect--positive or negative--the quality and reliability of human used for testing it also affect the factors mentioned above, especially failure data to be observedEvent-Based GUI Testing and Reliability Assessment Techniques An Experimental Insight

Memon, Atif M.

382

Research results for the Tornado Wind-Energy system: analysis and conclusions  

SciTech Connect

The Tornado Wind Energy System (TWES) concept utilizes a wind driven vortex confined by a hollow tower to create a low pressure core intended to serve as a turbine exhaust reservoir. The turbine inlet flow is provided by a separate ram air supply. Numerous experimental and analytical research efforts have investigated the potential of the TWES as a wind energy conversion system (WECS). The present paper summarizes and analyzes much of theresearch to date on the TWES. A simplified cost analysis incorporating these research results is also included. Based on these analyses, the TWES does not show significant promise of improving on either the performance or the cost of energy attainable by conventional WECS. The prospects for achieving either a system power coefficient above 0.20 or a cost of energy less than $0.50/kWh (1979 dollars) appear to be poor.

Jacobs, E.

1983-01-01

383

Research results for the Tornado wind energy system: analysis and conclusions  

SciTech Connect

The Tornado Wind Energy System (TWES) concept utilizes a wind-driven vortex confined by a hollow tower to create a low-pressure core intended to serve as a turbine exhaust reservoir. The turbine inlet flow is provided by a separate ram air supply. Numerous experimental and analytical research efforts have investigated the potential of the TWES as a wind energy conversion system (WECS). The present paper summarizes and analyzes much of the research to date on the TWES. A simplified cost analysis incorporating these research results is also included. Based on these analyses, the TWES does not show any significant promise of improving on either the performance or the cost of energy attainable by conventional WECS. The prospects for achieving either a system power coefficient above 0.20 or a cost of energy less than $0.50/kWh (1979 dollars) appear to be poor.

Jacobs, E.W.

1985-02-01

384

High-energy radiation damage in zirconia: modeling results  

SciTech Connect

Zirconia is viewed as a material of exceptional resistance to amorphization by radiation damage, and consequently proposed as a candidate to immobilize nuclear waste and serve as an inert nuclear fuel matrix. Here, we perform molecular dynamics simulations of radiation damage in zirconia in the range of 0.1-0.5 MeV energies with account of electronic energy losses. We nd that the lack of amorphizability co-exists with a large number of point defects and their clusters. These, importantly, are largely isolated from each other and therefore represent a dilute damage that does not result in the loss of long-range structural coherence and amorphization. We document the nature of these defects in detail, including their sizes, distribution and morphology, and discuss practical implications of using zirconia in intense radiation environments.

Zarkadoula, Evangelia [Queen Mary, University of London] [Queen Mary, University of London; Devanathan, Ram [Pacific Northwest National Laboratory (PNNL)] [Pacific Northwest National Laboratory (PNNL); Weber, William J [ORNL] [ORNL; Seaton, M [Daresbury Laboratory, UK] [Daresbury Laboratory, UK; Todorov, I T [Daresbury Laboratory, UK] [Daresbury Laboratory, UK; Nordlund, Kai [University of Helsinki] [University of Helsinki; Dove, Martin T [Queen Mary, University of London] [Queen Mary, University of London; Trachenko, Kostya [Queen Mary, University of London] [Queen Mary, University of London

2014-01-01

385

Experimental results from Al/p-CdTe/Pt X-ray detectors  

NASA Astrophysics Data System (ADS)

Recently, Al/CdTe/Pt detectors have been proposed for the development of high resolution X-ray spectrometers. Due to the low leakage currents, these detectors allow high electric fields and the pixellization of anodes with the possibility to realize single charge carrier sensing detectors. In this work, we report on the results of electrical and spectroscopic investigations on CdTe diode detectors with Al/CdTe/Pt electrode configuration (4.14.10.75 and 4.14.12 mm3). The detectors are characterized by very low leakage currents in the reverse bias operation: 0.3 nA at 25 C and 2.4 pA at -25 C under a bias voltage of -1000 V. The spectroscopic performance of the detectors at both low and high photon counting rates were also investigated with a focus on the minimization of time instability, generally termed as polarization, looking for the optimum bias voltage and temperature. Good time stability, during a long-term operation of 10 h, was observed for both detectors at -25 C and by using an electric field of 5000 V/cm. The 2 mm thick detector exhibited good energy resolution of 6.1%, 2.5% and 2.0% (FWHM) at 22.1 keV, 59.5 and 122.1 keV, respectively. Performance enhancements were obtained by using digital pulse processing techniques, especially at high photon counting rates (300 kcps). The 2 mm thick detector, after a digital pulse shape correction (PSC), is characterized by similar performance to the thin detector ones, opening up to the use of thick CdTe detectors without excessive performance degradations. This work was carried out in the framework of the development of portable X-ray spectrometers for both laboratory research and medical applications.

Abbene, L.; Gerardi, G.; Turturici, A. A.; Del Sordo, S.; Principato, F.

2013-12-01

386

Experimental determination of the energy generated in nuclear cascades by a high energy beam  

NASA Astrophysics Data System (ADS)

An already existing, sub-critical arrangement made of natural uranium and water moderator has been exposed to a low intensity (? 10 9 ppp) proton beam from CERN-PS at several kinetic energies from 600 MeV to 2.75 GeV. The energy delivered by the hadronic cascade induced by the beam in the device has been measured by the temperature rise of small sampling blocks of uranium located in several different positions inside the device and counting the fissions in thin probe foils of natural uranium. We find typically G ? 30 in reasonable agreement with calculations, where G is the ratio of the energy produced in the device to the energy delivered by the beam. This result opens the way to the realisation of the so-called Energy Amplifier, a practical device to produce energy from thorium or depleted uranium targets exposed to an intense high energy proton beam. Results show that the optimal kinetic is ? 1 GeV, below which G decreases but is still acceptable in the energy range explored

Andriamonje, S.; Angelopoulos, A.; Apostolakis, A.; Attale, F.; Brillard, L.; Buono, S.; Calero, J.; Carminati, F.; Casagrande, F.; Cennini, P.; Charalambous, S.; Del Moral, R.; Eleftheriadis, C.; Gallego, E.; Galvez, J.; Garcia-Tabares, L.; Geles, C.; Goulas, I.; Giorni, A.; Gonzalez, E.; Hussonnois, M.; Jaren, J.; Klapisch, R.; Kokkas, P.; Lemeilleur, F.; Lindecker, G.; Liolios, A.; Loiseaux, J. M.; Lopez, C.; Lorente, A.; Macri, M.; Martinez-Val, J. M.; Nifenecker, H.; Oropesa, J.; Pavlopoulos, P.; Pinston, J. A.; Revol, J.-P.; Roche, C.; Rubbia, C.; Rubio, J. A.; Sakelariou, K.; Sakelliou, L.; Saldana, F.; Schussler, F.; Tamarit, J.; Trubert, D.; Viano, J. B.; Vieira, S.; Vlachos, S.; Li, Xuan; Zarris, G.

1995-02-01

387

Theoretical and experimental studies of electrified interfaces relevant to energy storage.  

SciTech Connect

Advances in technology for electrochemical energy storage require increased understanding of electrolyte/electrode interfaces, including the electric double layer structure, and processes involved in charging of the interface, and the incorporation of this understanding into quantitative models. Simplified models such as Helmholtz's electric double-layer (EDL) concept don't account for the molecular nature of ion distributions, solvents, and electrode surfaces and therefore cannot be used in predictive, high-fidelity simulations for device design. This report presents theoretical results from models that explicitly include the molecular nature of the electrical double layer and predict critical electrochemical quantities such as interfacial capacitance. It also describes development of experimental tools for probing molecular properties of electrochemical interfaces through optical spectroscopy. These optical experimental methods are designed to test our new theoretical models that provide descriptions of the electric double layer in unprecedented detail.

Templeton, Jeremy Alan; Jones, Reese E.; Lee, Jonathan W.; Mandadapu, Kranthi Kiran; Kliewer, Christopher Jesse; Sasaki, Darryl Yoshio; Kane, Marie C.; Reyes, Karla Rosa; Hayden, Carl C.

2013-12-01

388

Computational and Experimental Studies of Turbulence in Wind and Hydrokinetic Energy: From Turbines to Farms  

NASA Astrophysics Data System (ADS)

Recent computational and experimental advances at the St. Anthony Falls Laboratory (SAFL) aimed at understanding the structure of turbulence past wind and hydrokinetic turbines and farms will be presented. A powerful computational framework has been developed for carrying out LES of turbulent flow past complete turbine configurations as well as large-scale wind farms. For the former, the geometrical details of the turbine are resolved on fine computational grids using the CURVIB method with a wall model (Kang et al., Adv. in Water Resources, 34(1), 98-113, 2011) while for the latter the turbines are parametrized as actuator disks. Laboratory experiments in the SAFL atmospheric boundary layer wind tunnel and a large water flume have provided data sets for model validation. The computed and experimental results yield novel insights into the structure of turbulence in turbine wakes and suggest strategies for optimizing layouts of multi-turbine arrays for maximizing energy capture.

Sotiropoulos, Fotis; Kang, Seokkoo; Yang, Xiaolei; Chamorro, Leonardo; Hill, Craig; Arndt, Roger

2011-11-01

389

An experimental/computational study of sharp fin induced shock wave/turbulent boundary layer interactions at Mach 5 - Experimental results  

NASA Technical Reports Server (NTRS)

A combined experimental/computational study has been performed of sharp fin induced shock wave/turbulent boundary layer interactions at Mach 5. The current paper focuses on the experiments and analysis of the results. The experimental data include mean surface heat transfer, mean surface pressure distributions and surface flow visualization for fin angles of attack of 6, 8, 10, 12, 14 and 16-degrees at Mach 5 under a moderately cooled wall condition. Comparisons between the results and correlations developed earlier show that Scuderi's correlation for the upstream influence angle (recast in a conical form) is superior to other such correlations in predicting the current results, that normal Mach number based correlations for peak pressure heat transfer are adequate and that the initial heat transfer peak can be predicted using pressure-interaction theory.

Rodi, Patrick E.; Dolling, David S.

1992-01-01

390

Molecular interactions between photosystem I and ferredoxin: an integrated energy frustration and experimental model.  

PubMed

The stromal domain (PsaC, PsaD, and PsaE) of photosystem I (PSI) reduces transiently bound ferredoxin (Fd) or flavodoxin. Experimental structures exist for all of these protein partners individually, but no experimental structure of the PSI/Fd or PSI/flavodoxin complexes is presently available. Molecular models of Fd docked onto the stromal domain of the cyanobacterial PSI site are constructed here utilizing X-ray and NMR structures of PSI and Fd, respectively. Predictions of potential protein-protein interaction regions are based on experimental site-directed mutagenesis and cross-linking studies to guide rigid body docking calculations of Fd into PSI, complemented by energy landscape theory to bring together regions of high energetic frustration on each of the interacting proteins. The results identify two regions of high localized frustration on the surface of Fd that contain negatively charged Asp and Glu residues. This study predicts that these regions interact predominantly with regions of high localized frustration on the PsaC, PsaD, and PsaE chains of PSI, which include several residues predicted by previous experimental studies. Copyright 2014 John Wiley & Sons, Ltd. PMID:25178855

Cashman, Derek J; Zhu, Tuo; Simmerman, Richard F; Scott, Cathy; Bruce, Barry D; Baudry, Jerome

2014-10-01

391

Experimental and analytical results of tangential blowing applied to a subsonic V/STOL inlet  

NASA Technical Reports Server (NTRS)

Engine inlets for subsonic V/STOL aircraft must operate over a wide range of conditions without internal flow separation. Experimental and analytical investigations were conducted to evaluate the effectiveness of tangential blowing to maintain attached flow to high angles of attack. The inlet had a relatively thin lip with a blowing slot located either on the lip or in the diffuser. The height and width of these slots was varied. Experimentally determined flow separation boundaries showed that lip blowing achieved higher angle of attack capability than diffuser blowing. This capability was achieved with the largest slot circumferential extent and either of the two slot heights. Predicted (analytical) separation boundaries showed good agreement except at the highest angles of attack.

Burley, R. R.; Hwang, D. P.

1982-01-01

392

Using Research Findings to Change School and Classroom Practices: Results of an Experimental Study  

Microsoft Academic Search

A quasi-experimental, treatment-control group investigation was designed to test the effects of introducing research findings from effective teaching and school leadership into ongoing school settings. Research findings were translated into observable staff developer and teacher behaviors. Following 5 days of training 3 weeks prior to the beginning of school, treatment staff developers implemented self-designed plans to increase effective teaching behaviors.

Gary A. Griffin; Susan Barnes

1986-01-01

393

Calcification in Chronically-Implanted Blood Pumps: Experimental Results and Review of the Literature  

PubMed Central

Blood compatibility is a major objective in the development of long-term, implantable circulatory assist (left ventricular assist devices) and replacement (total artificial heart) devices. An important problem in experimental studies in animals has been the propensity for calcification to occur at the blood/material interface. Presented is a summary of our experience (27 studies) with blood pump calcification and a review of the current literature regarding this complication. Images PMID:15226958

Turner, Stephen A.; Bossart, Mattie I.; Milam, John D.; Fuqua, John M.; Igo, Stephen R.; McGee, Michael G.; Frazier, O. Howard

1982-01-01

394

Promoting walking to school: results of a quasi-experimental trial  

Microsoft Academic Search

Study objective: To assess the impact of a combined intervention on childrens travel behaviour, stage of behavioural change and motivations for and barriers to actively commuting to school.Design: A quasi-experimental trial involving pre- and post-intervention mapping of routes to school by active and inactive mode of travel and surveys of stage of behaviour change and motivations for and barriers to

Rosie McKee; Nanette Mutrie; Fiona Crawford; Brian Green

2007-01-01

395

Preliminary experimental results of gas recycling subsystems except carbon dioxide concentration  

NASA Astrophysics Data System (ADS)

Oxygen concentration and separation is an essential factor for air recycling in a CELSS. Furthermore, if the value of the plant assimilatory quotient is not coincident with that of the animal respiratory quotient, the recovery of O2 from the concentrated CO2 through chemical methods will become necessary to balance the gas contents in a CELSS. Therefore, oxygen concentration and separation equipment using Salcomine and O2 recovery equipment, such as Sabatier and Bosch reactors, were experimentally developed and tested.

Otsuji, K.; Sawada, T.; Satoh, S.; Kanda, S.; Matsumura, H.; Kondo, S.; Otsubo, K.

396

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

Microsoft Academic Search

The performance of heat pipe solar collector is investigated theoretically and experimentally. The system employs wick-assisted\\u000a heat pipe for the heat transfer from the absorber (evaporator) to a heat exchanger (condenser). The heat pipe is made with\\u000a a copper tube and the evaporator section is finned with aluminium plate. Theoretical model predicts the outlet water from\\u000a heat exchanger, heat pipe

E. Azad

2009-01-01

397

Elasticity of mechanical oscillators in nonequilibrium steady states: experimental, numerical, and theoretical results.  

PubMed

We study experimentally, numerically, and theoretically the elastic response of mechanical resonators along which the temperature is not uniform, as a consequence of the onset of steady-state thermal gradients. Two experimental setups and designs are employed, both using low-loss materials. In both cases, we monitor the resonance frequencies of specific modes of vibration, as they vary along with variations of temperatures and of temperature differences. In one case, we consider the first longitudinal mode of vibration of an aluminum alloy resonator; in the other case, we consider the antisymmetric torsion modes of a silicon resonator. By defining the average temperature as the volume-weighted mean of the temperatures of the respective elastic sections, we find out that the elastic response of an object depends solely on it, regardless of whether a thermal gradient exists and, up to 10% imbalance, regardless of its magnitude. The numerical model employs a chain of anharmonic oscillators, with first- and second-neighbor interactions and temperature profiles satisfying Fourier's Law to a good degree. Its analysis confirms, for the most part, the experimental findings and it is explained theoretically from a statistical mechanics perspective with a loose notion of local equilibrium. PMID:23005235

Conti, Livia; De Gregorio, Paolo; Bonaldi, Michele; Borrielli, Antonio; Crivellari, Michele; Karapetyan, Gagik; Poli, Charles; Serra, Enrico; Thakur, Ram-Krishna; Rondoni, Lamberto

2012-06-01

398

Overview of the Manitou Experimental Forest Observatory: site description and selected science results from 2008-2013  

NASA Astrophysics Data System (ADS)

The Bio-hydro-atmosphere interactions of Energy, Aerosols, Carbon, H2O, Organics & Nitrogen (BEACHON) project seeks to understand the feedbacks and inter-relationships between hydrology, biogenic emissions, carbon assimilation, aerosol properties, clouds and associated feedbacks within water-limited ecosystems. The Manitou Experimental Forest Observatory (MEFO) was established in 2008 by the National Center for Atmospheric Research to address many of the BEACHON research objectives, and it now provides a fixed field site with significant infrastructure. MEFO is a mountainous, semi-arid ponderosa pine-dominated forest site that is normally dominated by clean continental air, but is periodically influenced by anthropogenic sources from Colorado Front Range cities. This article summarizes the past and ongoing research activities at the site, and highlights some of the significant findings that have resulted from these measurements. These activities include: - soil property measurements, - hydrological studies, - measurements of high-frequency turbulence parameters, - eddy covariance flux measurements of water, energy, aerosols and carbon dioxide through the canopy, - biogenic and anthropogenic volatile organic compound emissions and their influence on regional atmospheric chemistry, - aerosol number and mass distributions, - chemical speciation of aerosol particles, - characterization of ice and cloud condensation nuclei, - trace gas measurements, and - model simulations using coupled chemistry and meteorology. In addition to various long-term continuous measurement, three focused measurement campaigns with state-of-the-art instrumentation have taken place since the site was established, and two of these are the subjects of this special issue: BEACHON-ROCS (Rocky Mountain Organic Carbon Study, 2010) and BEACHON-RoMBAS (Rocky Mountain Biogenic Aerosol Study, 2011).

Ortega, J.; Turnipseed, A.; Guenther, A. B.; Karl, T. G.; Day, D. A.; Gochis, D.; Huffman, J. A.; Prenni, A. J.; Levin, E. J. T.; Kreidenweis, S. M.; DeMott, P. J.; Tobo, Y.; Patton, E. G.; Hodzic, A.; Cui, Y.; Harley, P. C.; Hornbrook, R. H.; Apel, E. C.; Monson, R. K.; Eller, A. S. D.; Greenberg, J. P.; Barth, M.; Campuzano-Jost, P.; Palm, B. B.; Jimenez, J. L.; Aiken, A. C.; Dubey, M. K.; Geron, C.; Offenberg, J.; Ryan, M. G.; Fornwalt, P. J.; Pryor, S. C.; Keutsch, F. N.; DiGangi, J. P.; Chan, A. W. H.; Goldstein, A. H.; Wolfe, G. M.; Kim, S.; Kaser, L.; Schnitzhofer, R.; Hansel, A.; Cantrell, C. A.; Mauldin, R. L., III; Smith, J. N.

2014-01-01

399

First experimental results on the kinetic processes in a surface-wave-sustained argon discharge at atmospheric pressure  

SciTech Connect

This communication presents an advance of the results of an experimental study of the kinetic processes in a surface-wave-sustained argon discharge at atmospheric pressure. We utilize the study developed by Fujimoto on the population and depopulation processes of the excited levels of atoms and ions. This theory has been applied by S. Daviaud and A. Hirabayashi to explain the kinetic processes in helium plasma at low pressure. Fujimoto has studied the ionization and recombination mechanisms of the plasma under various conditions and its relation to the population density distributions. This study establishes, for an hydrogenic ion with a core charge z, different zones in the atomic system (level map). Each zone is characterized by the dominant mechanisms of the population and depopulation of their excited levels, A level is characterized for the effective principal quantum number p, where p = z (E{sub H}/{vert_bar}E{sub p}{vert_bar}){sup 1/2}, E{sub H} is the hydrogen ionization energy and {vert_bar}E{sub p}{vert_bar} is the energy required to ionize the atom from the level considered. The population of each level p can be expressed in terms of the parameter b(p) defined as n(p)/n{sup SB}(p), n(p) and n{sup SB}(p) being the actual population and the Saha-Boltzmann equilibrium population of the level, respectively. Figure I shows the population and depopulation processes of a level p, which are both collisional and radiative that are characterized by their respective coefficients.

Calzada, M.D.; Gamero, A.; Sola, A. [Universidad de Cordoba (Spain)] [and others

1995-12-31

400

Simple Experimental Verification of the Relation between the Band-Gap Energy and the Energy of Photons Emitted by LEDs  

ERIC Educational Resources Information Center

The wavelength of the light emitted by a light-emitting diode (LED) is intimately related to the band-gap energy of the semiconductor from which the LED is made. We experimentally estimate the band-gap energies of several types of LEDs, and compare them with the energies of the emitted light, which ranges from infrared to white. In spite of

Precker, Jurgen W.

2007-01-01

401

Experimental Results of the Impact of an Ion Thruster Plasma on Microwave Propagation  

NASA Technical Reports Server (NTRS)

Electric thrusters are being considered for a variety of space missions because of the significant propellant savings that result from the use of high performance, electric propulsion technologies. Propellant mass savings reduces spacecraft launch requirements and increases mission lifetime and payload. The impact of electric thruster plasma plumes on microwave signal propagation however is an important spacecraft integration concern. Arcjets were the first electric thrusters to be considered for operational missions. Ling, et al. studied the effect of arcjet plumes on propagation. Arcjets produce a lightly ionized plume and Ling's analysis predicted that the plume would have a negligible effect on communication. Plumes from the higher performance ion thrusters being developed exhibit higher ionization levels, plasma temperatures and particle velocities than arcjets. Therefore, there was a need to assess the impact due to these plumes. To address this need, the authors designed and performed a series of experiments to examine propagation effects of plumes. The challenge with these experiments was that they had to be performed in the operational environment of the thruster. Therefore, the experiments were conducted inside a metal chamber which could be depressurized to simulate a near vacuum condition of space. The metal chamber presents a potential large source of error to the propagation measurements due to the corruption of the desired data by multiple wall reflections within the chamber. This chamber effect was minimized by employing a pulsed-continuous wave transmitter and receiver system. This system based on an HP8510 Network Analyzer, uses external hardware time gating to eliminate the clutter of the spurious reflections. Additionally, high gain antennas were used in the measurements to ensure that minimal amounts of energy were transmitted/received in undesirable directions. The measurements took place in Vacuum Facility 5 of the Electric Propulsion Laboratory at the NASA Glenn Research Center. This facility utilizes a cylindrical, stainless steel, vacuum chamber, which is 18.3 m long and 4.6 m in diameter. For the tests being described here a 30 cm diameter, xenon ion thruster was used. The thruster provided between 500 W and 2.3 kW of operating power. The thruster was mounted on a stand along the axis of the chamber near one of its ends and could be moved axially.

Zaman, Afroz J.; Lambert, Kevin M.

2000-01-01

402

Experimental Results of the Impact of an Ion Thruster Plasma on Microwave Propagation  

NASA Technical Reports Server (NTRS)

Electric thrusters are being considered for a variety of space missions because of the significant propellant savings that result from the use of high performance, electric propulsion technologies, Propellant mass savings reduces spacecraft launch requirements and increases mission lifetime and payload. The impact of electric thruster plasma plumes on microwave signal propagation however is an important spacecraft integration concern. Arcjets were the first electric thrusters to be considered for operational missions. Ling, et al., studied the effect of arcjet plumes on propagation. Arcjets produce a lightly ionized plume and Ling's analysis predicted that the plume would have a negligible effect on communication. Plumes from the higher performance ion thrusters being developed exhibit higher ionization levels, plasma temperatures and particle velo@ities than arcjets. Therefore, there was a need to assess the impact due to these plumes. To address this need, the authors designed and performed a series of experiments to examine propagation effects of plumes. The challenge with these experiments was that they had to be performed in the operational environment of the thruster. Therefore, the experiments were conducted inside a metal chamber which could be depressurized to simulate a near vacuum condition of space. The metal chamber presents a potential large source of error to the propagation measurements due to the corruption of the desired data by multiple wall reflections within the chamber. This chamber effect was minimized by employing a pulsed-continuous wave transmitter and receiver system. This system, based on an HP8510 Network Analyzer, uses external hardware time gating to eliminate the clutter of the spurious reflections. Additionally, high gain antennas were used in the measurements to ensure that minimal amounts of energy ",ere transmitted/received in undesirable directions. The measurements took place in Vacuum Facility 5 of the Electric Propulsion Laboratory at the NASA Glenn Research Center. This facility utilizes a cylindrical, stainless steel, vacuum chamber, which is 18.3 m long and 4.6 m in diameter. For the tests being described here a 30 cm diameter, xenon ion thruster was used. The thruster provided between 500 W and 2.3 kW of operating power. The thruster was mounted on a stand along the axis of the chamber near one of its ends.

Zaman, Afroz J.; Lambert, Kevin M.

2000-01-01

403

Recent results from experimental studies on laser-plasma coupling in a shock ignition relevant regime  

NASA Astrophysics Data System (ADS)

Shock ignition (SI) is an appealing approach in the inertial confinement scenario for the ignition and burn of a pre-compressed fusion pellet. In this scheme, a strong converging shock is launched by laser irradiation at an intensity I?2 > 1015 W cm-2 m2 at the end of the compression phase. In this intensity regime, laser-plasma interactions are characterized by the onset of a variety of instabilities, including stimulated Raman scattering, Brillouin scattering and the two plasmon decay, accompanied by the generation of a population of fast electrons. The effect of the fast electrons on the efficiency of the shock wave production is investigated in a series of dedicated experiments at the Prague Asterix Laser Facility (PALS). We study the laser-plasma coupling in a SI relevant regime in a planar geometry by creating an extended preformed plasma with a laser beam at 7 1013 W cm-2 (250 ps, 1315 nm). A strong shock is launched by irradiation with a second laser beam at intensities in the range 1015-1016 W cm-2 (250 ps, 438 nm) at various delays with respect to the first beam. The pre-plasma is characterized using x-ray spectroscopy, ion diagnostics and interferometry. Spectroscopy and calorimetry of the backscattered radiation is performed in the spectral range 250-850 nm, including (3/2)?, ? and ?/2 emission. The fast electron production is characterized through spectroscopy and imaging of the K? emission. Information on the shock pressure is obtained using shock breakout chronometry and measurements of the craters produced by the shock in a massive target. Preliminary results show that the backscattered energy is in the range 3-15%, mainly due to backscattered light at the laser wavelength (438 nm), which increases with increasing the delay between the two laser beams. The values of the peak shock pressures inferred from the shock breakout times are lower than expected from 2D numerical simulations. The same simulations reveal that the 2D effects play a major role in these experiments, with the laser spot size comparable with the distance between critical and ablation layers.

Koester, P.; Antonelli, L.; Atzeni, S.; Badziak, J.; Baffigi, F.; Batani, D.; Cecchetti, C. A.; Chodukowski, T.; Consoli, F.; Cristoforetti, G.; De Angelis, R.; Folpini, G.; Gizzi, L. A.; Kalinowska, Z.; Krousky, E.; Kucharik, M.; Labate, L.; Levato, T.; Liska, R.; Malka, G.; Maheut, Y.; Marocchino, A.; Nicolai, P.; O'Dell, T.; Parys, P.; Pisarczyk, T.; Raczka, P.; Renner, O.; Rhee, Y. J.; Ribeyre, X.; Richetta, M.; Rosinski, M.; Ryc, L.; Skala, J.; Schiavi, A.; Schurtz, G.; Smid, M.; Spindloe, C.; Ullschmied, J.; Wolowski, J.; Zaras, A.

2013-12-01

404

Early times and thermalization in heavy ion collisions: a summary of experimental results for photons, light vector mesons, open and hidden heavy flavors  

E-print Network

This contribution summarizes the main experimental results presented at the 2009 Quark Matter conference concerning single and dilepton production in proton and heavy ion collisions at high energy. The dilepton invariant mass spectrum has been measured over a range that extends from the $\\pi^0$ mass to the $\\Upsilon$ mass, and for various collision energies at SPS, Fermilab, Hera and RHIC. This paper focuses on the various contributions (photons, low mass vector mesons, open and hidden heavy flavors) to this spectrum and discuss their implications on our understanding of the matter formed in heavy ion collisions.

Hugo Pereira Da Costa

2009-08-21

405

Investigations in Experimental and Theoretical High Energy Physics  

SciTech Connect

We report on the work done under DOE grant DE-FG02-01ER41155. The experimental tasks have ongoing efforts at CERN (ATLAS), the Whipple observatory (VERITAS) and R&D work on dual readout calorimetry and neutrino-less double beta decay. The theoretical task emphasizes the weak interaction and in particular CP violation and neutrino physics. The detailed descriptions of the final report on each project are given under the appropriate task section of this report.

Krennrich, Frank [Iowa State University

2013-07-29

406

A research program in experimental high energy physics  

NASA Astrophysics Data System (ADS)

An experimental program in strong and electro-weak interaction physics of elementary particles is being carried out using electronic detection techniques. Experiments have been performed at Brown, Brookhaven, and Fermilab. The work described in this report by the Electronic Detector Group addresses the following: neutrino interactions and intrinsic properties, preparations for experiments (D-ZERO) at the FNAL 2 TeV antiproton-proton Collider, new detection techniques for neutrino properties.

Lanou, R. E., Jr.; Cutts, D.

1990-07-01

407

Simulation of diurnal thermal energy storage systems: Preliminary results  

NASA Astrophysics Data System (ADS)

This report describes the results of a simulation of thermal energy storage (TES) integrated with a simple-cycle gas turbine cogeneration system. Integrating TES with cogeneration can serve the electrical and thermal loads independently while firing all fuel in the gas turbine. The detailed engineering and economic feasibility of diurnal TES systems integrated with cogeneration systems has been described in two previous PNL reports. The objective of this study was to lay the ground work for optimization of the TES system designs using a simulation tool called TRNSYS (TRaNsient SYstem Simulation). TRNSYS is a transient simulation program with a sequential-modular structure developed at the Solar Energy Laboratory, University of Wisconsin-Madison. The two TES systems selected for the base-case simulations were: (1) a one-tank storage model to represent the oil/rock TES system; and (2) a two-tank storage model to represent the molten nitrate salt TES system. Results of the study clearly indicate that an engineering optimization of the TES system using TRNSYS is possible. The one-tank stratified oil/rock storage model described here is a good starting point for parametric studies of a TES system. Further developments to the TRNSYS library of available models (economizer, evaporator, gas turbine, etc.) are recommended so that the phase-change processes is accurately treated.

Katipamula, S.; Somasundaram, S.; Williams, H. R.

1994-12-01

408

PUBLISHED ONLINE: 29 JULY 2012 | DOI: 10.1038/NPHYS2375 Experimental free-energy measurements  

E-print Network

ARTICLES PUBLISHED ONLINE: 29 JULY 2012 | DOI: 10.1038/NPHYS2375 Experimental free-energy-molecule technologies have made it possible to use irreversible work measurements to extract free-energy differences associated with the mechanical (un)folding of molecules. To date, free-energy recovery has been focused

Loss, Daniel

409

Slepton mass splittings and cLFV in the SUSY seesaw in the light of recent experimental results  

NASA Astrophysics Data System (ADS)

Following recent experimental developments, in this study we re-evaluate if the interplay of high- and low-energy lepton flavour violating observables remains a viable probe to test the high-scale type-I supersymmetric seesaw. Our analysis shows that fully constrained supersymmetric scenarios no longer allow to explore this interplay, since recent LHC data precludes the possibility of having sizeable slepton mass differences for a slepton spectrum sufficiently light to be produced, and in association to BR( ? ? e?) within experimental reach. However, relaxing the strict universality of supersymmetric soft-breaking terms and fully exploring heavy neutrino dynamics, still allows to have slepton mass splittings , for slepton masses accessible at the LHC, with associated ? ? e? rates within future sensitivity. For these scenarios, we illustrate how the correlation between high- and low-energy lepton flavour violating observables allows to probe the high-scale supersymmetric seesaw.

Figueiredo, A. J. R.; Teixeira, A. M.

2014-01-01

410

A comprehensive experimental program for investigation of various Omega operational modes with selected data analysis results  

NASA Technical Reports Server (NTRS)

The investigations considered are concerned with a better definition of the achievable accuracy and propagation characteristics of Omega and the provision of data which could be used for an analysis to study the potential application of Omega position determination to support other NASA projects. The data collection program is considered along with the experimental equipment employed. Attention is given to the design of the receiving station, aspects of data processing, position measurement errors, differential errors, problems of lane decision, and the definition of the update rate.

Lytle, C. D.; Bradshaw, E. S.; Jowers, L. J.

1974-01-01

411

BIB Detector for astrophysics applications: Principle of operation, technology and first experimental results  

NASA Astrophysics Data System (ADS)

This paper is a presentation of the activity that has been performed in the domain of Blocked Impurity Band detector, from the operating principle to the characterization. This study has been performed commonly with IMEC in Belgium, MPIA Heidelberg and Thales Alenia Space in Cannes. The presentation deals with: A brief description of the context and the organization of the study. A description of the BIB detector operating principle. A short presentation of the technological steps for the detector fabrication. The main outcomes of the experimentation at diode level and at array level.

Israbian, C.

412

Preliminary experimental results of gas recycling subsystems except carbon dioxide concentration  

NASA Technical Reports Server (NTRS)

Oxygen concentration and separation is an essential factor for air recycling in a controlled ecological life support system (CELSS). Furthermore, if the value of the plant assimilatory quotient is not coincident with that of the animal respiratory quotient, the recovery of oxygen from the concentrated CO2 through chemical methods will become necessary to balance the gas contents in a CELSS. Therefore, oxygen concentration and separation equipment using Salcomine and O2 recovery equipment, such as Sabatier and Bosch reactors, were experimentally developed and tested.

Otsuji, K.; Sawada, T.; Satoh, S.; Kanda, S.; Matsumura, H.; Kondo, S.; Otsubo, K.

1987-01-01

413

Literature review and experimental results for a cylinder with perforations and protrusions at high Reynolds numbers  

NASA Technical Reports Server (NTRS)

The NASA Langley Low Turbulence Pressure Tunnel has been used to conduct an experimental study of the flow around a series of circular cylinders; the models used consisted of a baseline, smooth cylinder together with a cylinder that could be reconfigured with six different arrangements of two types of surface irregularity. Mean lift and drag forces were measured on all seven model configurations, and correlations were made between unsteady pressure in the wake region and fluctuating lift forces, in order to identify coherent structures.

Jones, G. S.; Horvath, T. J.; Stainback, P. C.; Beasley, W. D.; Mcghee, R. J.

1987-01-01

414

Cavity-Enhanced Frequency-Agile Rapid Scanning (fars) Spectroscopy: Experimental Realizations and Measurement Results  

NASA Astrophysics Data System (ADS)

We present a series of experimental realizations of cavity-enhanced, frequency-agile rapid scanning (FARS) spectroscopy using distributed feedback diode lasers, external cavity diode lasers, and ultra-narrow linewidth fiber lasers. FARS offers a scanning rate which is limited only by the cavity response time itself as well as a microwave-level frequency axis. Finally, it allows for an absorption sensitivity which is one of the highest ever reported. These realizations offer a range of applications from low-cost field measurements of trace gases to laboratory-based metrology.

Long, David A.; Truong, Gar-Wing; Zee, Roger Van; Plusquellic, David F.; Hodges, Joseph T.

2013-06-01

415

Results of experimental tests and calibrations of the surface neutron moisture measurement probe  

SciTech Connect

The surface neutron moisture probe has been tested both to demonstrate that is is able to operate in the expected in-tank temperature and gamma-ray fields and to provide detector responses to known moisture concentration materials. The probe will properly function in a simultaneous high temperature (80 degrees C) and high gamma radiation field (210 rad/hr)environment. Comparisons between computer model predicted and experimentally measured detector responses to changes in moisture provide a basis for the probe calibration to in-tank moisture concentrations.

Watson, W.T.; Bussell, J.H., Westinghouse Hanford

1996-08-13

416

Experimental study of spectral energy fluxes in turbulence generated by a fractal, tree-like object  

NASA Astrophysics Data System (ADS)

We report on an experimental study of the kinetic energy fluxes between scales in the turbulent near-wake flow downstream of a fractal, tree-like object. Experiments are performed in a liquid channel and data are acquired using planar Particle Image Velocimetry (PIV). The data are analyzed based on the filtering framework of relevance to Large Eddy Simulations. The flow and energy fluxes differ from the case of a canonical flow such as the cylinder wake, where typically kinetic energy is injected into turbulence by an object characterized by a single, well-defined, length-scale. For a fractal tree-like object, we find that the measured energy flux is strongly dependent on scale. In the present flow, scale-dependent injection of kinetic energy into the cascade arises from production as well as spatial transport terms. The injection rate spectrum is evaluated directly from the data by quantifying the rate of change of spectral energy flux as a function of wavenumber. The net injection rate spectrum is observed to scale approximately as k-7/3, in accordance with heuristic and dimensional arguments previously used for the kinetic energy production rate spectrum in shear flows. In order to scale the results, we consider an equivalent mixing length-scale that can be obtained from the tree geometry by adding over the relevant scales of successive branch clusters. In prior work, this equivalent length scale has been found to collapse the eddy-viscosity well. Here we find that this scale also collapses the energy flux and the net injection rate spectrum successfully.

Bai, Kunlun; Meneveau, Charles; Katz, Joseph

2013-11-01

417

Fatigue fracture in thin plates subjected to tensile and shearing loads - Crack tip fields, J integral and preliminary experimental results  

NASA Technical Reports Server (NTRS)

In one scenario of a crack in an airplane fuselage, the crack is subjected to cyclic tensile and out of plane shearing loads. To predict the fatigue crack growth in such a situation, experiments are being performed to measure the crack growth rate in laboratory specimens subjected to similar loadings. The mechanics of this problem are reviewed, the energy release rate is calculated and designs for an experiment are discussed along with some preliminary experimental observations.

Zehnder, Alan T.; Viz, Mark J.; Ingraffea, Anthony R.

1992-01-01

418

Negative Refraction and Energy Funneling by Hyperbolic Materials: An Experimental Demonstration in Acoustics  

NASA Astrophysics Data System (ADS)

This Letter reports the design, fabrication, and experimental characterization of hyperbolic materials showing negative refraction and energy funneling of airborne sound. Negative refraction is demonstrated using a stack of five holey Plexiglas plates where their thicknesses, layer separation, hole diameters, and lattice periodicity have been determined to show hyperbolic dispersion around 40 kHz. The resulting hyperbolic material shows a flat band profile in the equifrequency contour allowing the gathering of acoustic energy in a broad range of incident angles and its funneling through the material. Our demonstrations foresee interesting developments based on both phenomena. Acoustic imaging with subwavelength resolution and spot-size converters that harvest and squeeze sound waves irradiating from many directions into a collimated beam are just two possible applications among many.

Garca-Chocano, Victor M.; Christensen, Johan; Snchez-Dehesa, Jos

2014-04-01

419

Experimental Results in Synchronous-Clock One-Way-Travel-Time Acoustic Navigation for Autonomous Underwater Vehicles  

E-print Network

by other standard navigation means. Initial results for a maximum- likelihood sensor fusion frameworkExperimental Results in Synchronous-Clock One-Way-Travel-Time Acoustic Navigation for Autonomous in the development and deployment of a synchronous-clock acous- tic navigation system suitable for the simultaneous

Whitcomb, Louis L.

420

The yield strength of subliquidus basalts experimental results S.R. Hoover, K.V. Cashman*, M. Manga  

E-print Network

The yield strength of subliquidus basalts Ð experimental results S.R. Hoover, K.V. Cashman*, M 2000; revised 11 December 2000; accepted 11 December 2000 Abstract Yield strength is an important, the onset of yield strength may result in threshold transitions in ¯ow behavior and ¯ow surface morphology

Manga, Michael

421

Adaptive wave field synthesis for active sound field reproduction: experimental results.  

PubMed

Sound field reproduction has applications in music reproduction, spatial audio, sound environment reproduction, and experimental acoustics. Sound field reproduction can be used to artificially reproduce the spatial character of natural hearing. The objective is then to reproduce a sound field in a real reproduction environment. Wave field synthesis (WFS) is a known open-loop technology which assumes that the reproduction environment is anechoic. The room response thus reduces the quality of