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1

Energy-resolved computed tomography: first experimental results.  

PubMed

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. PMID:18799830

Shikhaliev, Polad M

2008-10-21

2

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

3

Experimental results from CERN on reaction mechanisms in high energy heavy ion collisions  

SciTech Connect

Three main experimental results from CERN concerning reaction mechanisms in high energy heavy ion collisions are discussed: (1) the striking validity of the single particle picture, (2) the nuclear stopping power and (3) the attained energy densities.

Sorensen, S.P. (Oak Ridge National Lab., TN (USA) Tennessee Univ., Knoxville, TN (USA). Dept. of Physics)

1990-01-01

4

Preliminary results of the large experimental wind turbine phase of the national wind energy program  

NASA Technical Reports Server (NTRS)

The preliminary results of two projects in the development phase of reliable wind turbines designed to supply cost-competitive electrical energy were discussed. An experimental 100 kW wind turbine design and its status are first reviewed. The results of two parallel design studies for determining the configurations and power levels for wind turbines with minimum energy costs are also discussed. These studies predict wind energy costs of 1.5 to 7 cents per kW-h for wind turbines produced in quantities of 100 to 1000 per year and located at sites having average winds of 12 to 18 mph.

Thomas, R. L.; Sholes, T.; Sholes, J. E.

1975-01-01

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

Preliminary results of the large experimental wind turbine phase of the national wind energy program  

NASA Technical Reports Server (NTRS)

A major phase of the wind energy program is the development of reliable wind turbines for supplying cost-competitive electrical energy. This paper discusses the preliminary results of two projects in this phase of the program. First an experimental 100 kW wind turbine design and its status are reviewed. Also discussed are the results of two parallel design studies for determining the configurations and power levels for wind turbines with minimum energy costs. These studies show wind energy costs of 7 to 1.5 c/kWH for wind turbines produced in quantities of 100 to 1000 a year and located at sites having average winds of 12 to 18 mph.

Thomas, R. L.; Sholes, J. E.

1975-01-01

7

Optimal piezoelectric beam shape for single and broadband vibration energy harvesting: Modeling, simulation and experimental results  

NASA Astrophysics Data System (ADS)

Harvesting energy from the surroundings has become a new trend in saving our environment. Among the established ones are solar panels, wind turbines and hydroelectric generators which have successfully grown in meeting the world's energy demand. However, for low powered electronic devices; especially when being placed in a remote area, micro scale energy harvesting is preferable. One of the popular methods is via vibration energy scavenging which converts mechanical energy (from vibration) to electrical energy by the effect of coupling between mechanical variables and electric or magnetic fields. As the voltage generated greatly depends on the geometry and size of the piezoelectric material, there is a need to define an optimum shape and configuration of the piezoelectric energy scavenger. In this research, mathematical derivations for unimorph piezoelectric energy harvester are presented. Simulation is done using MATLAB and COMSOL Multiphysics software to study the effect of varying the length and shape of the beam to the generated voltage. Experimental results comparing triangular and rectangular shaped piezoelectric beam are also presented.

Muthalif, Asan G. A.; Nordin, N. H. Diyana

2015-03-01

8

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

NASA Technical Reports Server (NTRS)

The Thermal Energy Storage-1 (TES-1) is a flight experiment that flew on the Space Shuttle Columbia (STS-62), in March 1994, as part of the OAST-2 mission. TES-1 is the first experiment in a four experiment suite designed to provide data for understanding the long duration microgravity behavior of thermal energy storage fluoride salts that undergo repeated melting and freezing. Such data have never been obtained before and have direct application for the development of space-based solar dynamic (SD) power systems. These power systems will store solar energy in a thermal energy salt such as lithium fluoride or calcium fluoride. The stored energy is extracted during the shade portion of the orbit. This enables the solar dynamic power system to provide constant electrical power over the entire orbit. Analytical computer codes have been developed for predicting performance of a spaced-based solar dynamic power system. Experimental verification of the analytical predictions is needed prior to using the analytical results for future space power design applications. The four TES flight experiments will be used to obtain the needed experimental data. This paper will focus 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. The TES-1 conceptual development, hardware design, final development, and system verification testing were accomplished at the NASA lewis Research Center (LeRC). TES-1 was developed under the In-Space Technology Experiment Program (IN-STEP), which sponsors NASA, industry, and university flight experiments designed to enable and enhance space flight technology. The IN-STEP Program is sponsored by the Office of Space Access and Technology (OSAT).

Wald, Lawrence W.; Tolbert, Carol; Jacqmin, David

1995-01-01

9

Experimental Results on Diffraction  

E-print Network

Experimental Results on Diffraction Hadron Collider Physics Symposium May 28, 2008 Pierre Van Mechelen Pierre.VanMechelen@ua.ac.be #12;Pierre Van Mechelen - Experimental Results on Diffraction - Hadron Collider Physics Symposium -- May 28, 2008 2 Outline b, W, b, W, H Diffractive processes and kinematics

10

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

SciTech Connect

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

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

2008-07-08

11

Experimental Results from the Thermal Energy Storage-2 (TES-2) Flight Experiment  

NASA Technical Reports Server (NTRS)

Thermal Energy Storage-2 (TES-2) is a flight experiment that flew on the Space Shuttle Endeavour (STS-72), in January 1996. TES-2 originally flew with TES-1 as part of the OAST-2 Hitchhiker payload on the Space Shuttle Columbia (STS-62) in early 1994. The two experiments, TES-1 and TES-2 were identical except for the fluoride salts to be characterized. TES-1 provided data on lithium fluoride (LiF), TES-2 provided data on a fluoride eutectic (LiF/CaF2). Each experiment was a complex autonomous payload in a Get-Away-Special payload canister. TES-1 operated flawlessly for 22 hr. Results were reported in a paper entitled, Effect of Microgravity on Materials Undergoing Melting and Freezing-The TES Experiment, by David Namkoong et al. A software failure in TES-2 caused its shutdown after 4 sec of operation. TES-1 and 2 were the first experiments in a four experiment suite designed to provide data for understanding the long duration microgravity behavior of thermal energy storage salts that undergo repeated melting and freezing. Such data have never been obtained before and have direct application for the development of space-based solar dynamic (SD) power systems. These power systems will store energy in a thermal energy salt such as lithium fluoride or a eutectic of lithium fluoride/calcium difluoride. The stored energy is extracted during the shade portion of the orbit. This enables the solar dynamic power system to provide constant electrical power over the entire orbit. Analytical computer codes were developed for predicting performance of a space-based solar dynamic power system. Experimental verification of the analytical predictions were needed prior to using the analytical results for future space power design applications. The four TES flight experiments were to be used to obtain the needed experimental data. This paper will address the flight results from the first and second experiments, TES-1 and 2, in comparison to the predicted results from the Thermal Energy Storage Simulation (TESSIM) analytical computer code. An analysis of the TES-2 data was conducted by Cleveland State University Professor, Mounir Ibrahim. TESSIM validation was based on two types of results; temperature history of various points on the containment vessel and TES material distribution within the vessel upon return from flight. The TESSIM prediction showed close comparison with the flight data. Distribution of the TES material within the vessel was obtained by a tomography imaging process. The frozen TES material was concentrated toward the colder end of the canister. The TESSIM prediction indicated a similar pattern. With agreement between TESSIM and the flight data, a computerized representation was produced to show the movement and behavior of the void during the entire melting and freezing cycles.

Tolbert, Carol

2000-01-01

12

Heating stents with radio frequency energy to prevent tumor ingrowth: modeling and experimental results  

NASA Astrophysics Data System (ADS)

Stents are often inserted into internal orifices to treat blockage due to tumor ingrowth. Stents are favored due to their minimally invasive nature, possible avoidance of a surgical procedure, and their ability to palliate surgically non-resectable disease. Because of rapid tumor growth however, a treatment means to prevent overgrowth through the stent and resultant blockage is required. To further this goal, experiments were performed in which a stent was placed in tissue and heated with radiofrequency (RF) energy to coagulate a cylinder of tissue, thereby eradicating viable tissue in the proximity of the stent. Temperatures were measured at the central stent surface and edges over time during a 5 - 10 minute heating in phantom and in fresh tissue. In addition, a finite element model was used to simulate the electric field and temperature distribution. Blood flow was also introduced in the model by evaluating RF application to stents to determine effectiveness of the energy applications. Changing perfusion and tissue electrical conductivity as a function of temperature was applied as the tissue was heated to 100 degree(s)C. Results from the electric field model will be shown as well as the thermal distribution over time from the simulations. Lastly, results from the damage integral will be discussed.

Ryan, Thomas P.; Lawes, Kate; Goldberg, S. Nahum

1998-04-01

13

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

14

Charmonium 2007: New experimental results  

NASA Astrophysics Data System (ADS)

The most important experimental results in charmonium physics in the energy region above the threshold for open-charm production that were obtained in recent years are surveyed. The first measurements of the exclusive cross sections for e + e - ? D bar D , D bar D *, and D* bar D * processes are discussed along with the discovered decay ?(4415) ? bar D_2^* (2460). The properties of charmonium-like states, including the group of states Y (4260), Y (4325), and Y (4660) with quantum numbers of J PC = 1--; the X(3940) and X(4160) states discovered in the process of double charmonium production in e + e - annihilation; and the X(3872), Y(3940), and Z ±(4430) states found in B-meson decays, are presented.

Pakhlova, G. V.

2009-03-01

15

Experimental Test Results of Energy Efficient Transport (EET) High-Lift Airfoil in Langley Low-Turbulence Pressure Tunnel  

NASA Technical Reports Server (NTRS)

This report describes the results of an experimental study conducted in the Langley Low-Turbulence Pressure Tunnel to determine the effects of Reynolds number and Mach number on the two-dimensional aerodynamic performance of the Langley Energy Efficient Transport (EET) High-Lift Airfoil. The high-lift airfoil was a supercritical-type airfoil with a thickness-to- chord ratio of 0.12 and was equipped with a leading-edge slat and a double-slotted trailing-edge flap. The leading-edge slat could be deflected -30 deg, -40 deg, -50 deg, and -60 deg, and the trailing-edge flaps could be deflected to 15 deg, 30 deg, 45 deg, and 60 deg. The gaps and overlaps for the slat and flaps were fixed at each deflection resulting in 16 different configurations. All 16 configurations were tested through a Reynolds number range of 2.5 to 18 million at a Mach number of 0.20. Selected configurations were also tested through a Mach number range of 0.10 to 0.35. The plotted and tabulated force, moment, and pressure data are available on the CD-ROM supplement L-18221.

Morgan, Harry L., Jr.

2002-01-01

16

Experimental High Energy Physics  

E-print Network

Experimental High Energy Physics at the University of Toronto Faculty Members David Bailey Peter-energy physics research today is the culmination of centuries of searching for an understanding of the ultimate nature of matter. Over the last 30 years, the standard model of particle physics has gradually taken

17

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

18

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

SciTech Connect

Finite element calculations and measurements are compared for material and energy flow in a system to evaporate pure titanium. A 40 kW electron beam is used to heat the end of a 7.62 cm diameter cylindrical rod which is fed vertically through a water-cooled crucible. Vapor emanates from a liquid pool in which flow is driven strongly by buoyancy and capillary forces. At high evaporation rates, the vapor exerts strong shear and normal forces on the liquid-vapor interface. The MELT finite element code is used to calculate steady-state, axisymmetric flow and temperature fields along with liquid-solid and liquid-vapor interface locations. The influence of the vapor on the liquid top surface is treated using boundary conditions with parameters derived from Monte Carlo simulations. The upper and lower interfaces of the liquid pool are tracked using a mesh structured with rotating spines. Experimental evaporation rates are obtained from measured feed rates, and heat flow rates are determined from measured temperature rises in the cooling water. The finite element model provides a good representation of the measured evaporation rates, heat flows, and lower pool boundary locations.

McClelland, M A; Westerberg, K W; Meier, T C; Braun, D G; Frischknecht, K D; Anklam, T M

2003-05-12

19

A New Determination of the Binding Energy of Atomic Oxygen on Dust Grain Surfaces: Experimental Results and Simulations  

E-print Network

The energy to desorb atomic oxygen from an interstellar dust grain surface, $E_{\\rm des}$, is an important controlling parameter in gas-grain models; its value impacts the temperature range over which oxygen resides on a dust grain. However, no prior measurement has been done of the desorption energy. We report the first direct measurement of $E_{\\rm des}$ for atomic oxygen from dust grain analogs. The values of $E_{\\rm des}$ are $1660\\pm 60$~K and $1850\\pm 90$~K for porous amorphous water ice and for a bare amorphous silicate film, respectively, or about twice the value previously adopted in simulations of the chemical evolution of a cloud. We use the new values to study oxygen chemistry as a function of depth in a molecular cloud. For $n=10^4$ cm$^{-3}$ and $G_0$=10$^2$ ($G_0$=1 is the average local interstellar radiation field), the main result of the adoption of the higher oxygen binding energy is that H$_2$O can form on grains at lower visual extinction $A_{\\rm V}$, closer to the cloud surface. A higher ...

He, Jiao; Hopkins, Tyler; Vidali, Gianfranco; Kaufman, Michael J

2015-01-01

20

First results of an experimental study of the residual activity induced by high-energy uranium ions in steel and copper  

Microsoft Academic Search

First results of an experimental study of the residual activity induced by high-energy uranium ions are presented. As a preparatory work for constructing the FAIR facility at GSI, samples of stainless steel and copper were irradiated by 500MeV\\/u 238U ions and investigated by gamma-ray spectroscopy. The isotopes that contribute dominantly to the residual activity have been identified and their contributions

A. Fertman; E. Mustafin; R. Hinca; I. Strašík; M. Pavlovic; D. Schardt; N. Sobolevskiy; A. Golubev; B. Sharkov; G. Fehrenbacher; I. Hofmann; H. Iwase; E. Kozlova; G. Mustafina

2007-01-01

21

An overview of STAR experimental results  

NASA Astrophysics Data System (ADS)

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 ?{sNN} = 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 collective dynamics, electromagnetic probes, heavy-flavor, initial state physics, jets, QCD phase diagram, thermodynamics and hadron chemistry, and future experimental facilities, upgrades, and instrumentation[1]. 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.

Xu, Nu

2014-11-01

22

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

23

Mach 5 inlet CFD and experimental results  

NASA Technical Reports Server (NTRS)

An experimental research program was conducted in the NASA Lewis Research Center 10 x 10 ft supersonic wind tunnel. The 2-D inlet model was designed to study the Mach 3.0 to 5.0 speed range for an over-under turbojet plus ramjet propulsion system. The model was extensively instrumented to provide both analytical code validation data as well as inlet performance information. Support studies for the program include flow field predictions with both 3-D parabolized Navier-Stokes (PNS) and 3-D full Navier-Stokes (FNS) analytical codes. Analytical predictions and experimental results are compared.

Weir, Lois J.; Reddy, D. R.; Rupp, George D.

1989-01-01

24

Mach 5 inlet CFD and experimental results  

NASA Technical Reports Server (NTRS)

An experimental research program was conducted in the NASA Lewis Research Center 10 ft. by 10 ft. supersonic wind tunnel. The two-dimensional inlet model was designed to study the Mach 3.0 to 5.0 speed range for an 'over-under' turbojet plus ramjet propulsion system. The model was extensively instrumented to provide both analytical code validation data as well as inlet performance information. Support studies for the program include flow field predictions with both three-dimensional parabolized Navier-Stokes (PNS) and three-dimensional full Navier-Stokes (FNS) analytical codes. Analytical predictions and experimental results are compared.

Weir, Lois J.; Reddy, D. R.; Rupp, George D.

1989-01-01

25

Microwave radiometry for humanitarian demining: experimental results  

NASA Astrophysics Data System (ADS)

Previous modeling studies have indicated that a multi-frequency radiometer could prove advantageous for humanitarian demining due to the oscillatory patterns in brightness temperature versus frequency that would be observed in the presence of a sub-surface target. Initial experimental results are reported in this paper from a multi-frequency radiometer (MFRAD) system operating at 19 frequencies in the 2.1-6.5 GHz band. The basic design of MFRAD is reviewed, and the calibration and noise background removal procedures discussed. Experimental results with sub-surface metallic and styrofoam targets are then provided that demonstrate the predicted oscillatory behavior. An FFT-based detection algorithm is also described and applied to measured data. Further plans for experiments and tests with this system are also detailed.

Johnson, Joel T.; Kim, Hyunjin; Wiggins, David R.; Cheon, Yonghun

2002-08-01

26

A critical review of RHIC experimental results  

NASA Astrophysics Data System (ADS)

The relativistic heavy-ion collider (RHIC) was constructed to achieve an asymptotic state of nuclear matter in heavy-ion collisions, a near-ideal gas of deconfined quarks and gluons denoted quark-gluon plasma or QGP. RHIC collisions are indeed very different from the hadronic processes observed at the Bevalac and AGS, but high-energy elementary-collision mechanisms are also non-hadronic. The two-component model (TCM) combines measured properties of elementary collisions with the Glauber eikonal model to provide an alternative asymptotic limit for A-A collisions. RHIC data have been interpreted to indicate formation of a strongly-coupled QGP (sQGP) or "perfect liquid". In this review, I consider the experimental evidence that seems to support such conclusions and alternative evidence that may conflict with those conclusions and suggest different interpretations.

Trainor, Thomas A.

2014-07-01

27

A new method for the determination of the specific kinetic energy (SKE) released to pyroclastic particles at magmatic fragmentation: theory and first experimental results  

NASA Astrophysics Data System (ADS)

Brittle magmatic fragmentation plays a crucial role in explosive eruptions. It represents the starting point of hazardous explosive events that can affect large areas surrounding erupting volcanoes. Knowing the initial energy released during this fragmentation process is fundamental for the understanding of the subsequent dynamics of the eruptive gas-particle mixture and consequently for the forecasting of the erupting column's behavior. The specific kinetic energy (SKE) of the particles quantifies the initial velocity shortly after the fragmentation and is therefore a necessary variable to model the gas-particle conduit flow and eruptive column regime. In this paper, we present a new method for its determination based on fragmentation experiments and identification of the timings of energy release. The results obtained on compositions representative for basaltic and phonolitic melts show a direct dependence on magma material properties: poorly vesiculated basaltic melts from Stromboli show the highest SKE values ranging from 7.3 to 11.8 kJ/kg, while experiments with highly vesiculated samples from Stromboli and Vesuvius result in lower SKE values (3.1 to 3.8 kJ/kg). The described methodology presents a useful tool for quantitative estimation of the kinetic energy release of magmatic fragmentation processes, which can contribute to the improvement of hazard assessment.

Dürig, Tobias; Dioguardi, Fabio; Büttner, Ralf; Dellino, Pierfrancesco; Mele, Daniela; Zimanowski, Bernd

2012-05-01

28

Overview of the Initial NSTX Experimental Results  

SciTech Connect

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

Ono, M. [Princeton Plasma Physics Laboratory (PPPL)] [Princeton Plasma Physics Laboratory (PPPL); Bell, M. [Princeton Plasma Physics Laboratory (PPPL)] [Princeton Plasma Physics Laboratory (PPPL); Bell, R. E. [Princeton Plasma Physics Laboratory (PPPL)] [Princeton Plasma Physics Laboratory (PPPL); Bigelow, Tim S [ORNL] [ORNL; Bitter, M. [Princeton Plasma Physics Laboratory (PPPL)] [Princeton Plasma Physics Laboratory (PPPL); Blanchard, W. [Princeton Plasma Physics Laboratory (PPPL)] [Princeton Plasma Physics Laboratory (PPPL); Darrow, D. [Princeton Plasma Physics Laboratory (PPPL)] [Princeton Plasma Physics Laboratory (PPPL); Fredrickson, E. [Princeton Plasma Physics Laboratory (PPPL)] [Princeton Plasma Physics Laboratory (PPPL); Gates, D. [Princeton Plasma Physics Laboratory (PPPL)] [Princeton Plasma Physics Laboratory (PPPL); Grisham, L. [Princeton Plasma Physics Laboratory (PPPL)] [Princeton Plasma Physics Laboratory (PPPL); Hosea, J. [Princeton Plasma Physics Laboratory (PPPL)] [Princeton Plasma Physics Laboratory (PPPL); Kaye, S. [Princeton Plasma Physics Laboratory (PPPL)] [Princeton Plasma Physics Laboratory (PPPL); Kaita, R. [Princeton Plasma Physics Laboratory (PPPL)] [Princeton Plasma Physics Laboratory (PPPL); Kubota, S. [University of California, Los Angeles] [University of California, Los Angeles; Kugel, H. [Princeton Plasma Physics Laboratory (PPPL)] [Princeton Plasma Physics Laboratory (PPPL); Johnson, D. [Princeton Plasma Physics Laboratory (PPPL)] [Princeton Plasma Physics Laboratory (PPPL); LeBlanc, B [Princeton Plasma Physics Laboratory (PPPL)] [Princeton Plasma Physics Laboratory (PPPL); Maingi, Rajesh [ORNL] [ORNL; Maqueda, R. [Los Alamos National Laboratory (LANL)] [Los Alamos National Laboratory (LANL); Mazzucato, E. [Princeton Plasma Physics Laboratory (PPPL)] [Princeton Plasma Physics Laboratory (PPPL); Menard, J. [Princeton Plasma Physics Laboratory (PPPL)] [Princeton Plasma Physics Laboratory (PPPL); Mueller, D. [Princeton Plasma Physics Laboratory (PPPL)] [Princeton Plasma Physics Laboratory (PPPL); Nelson, Brad E [ORNL] [ORNL; Neumeyer, C. L. [Princeton Plasma Physics Laboratory (PPPL)] [Princeton Plasma Physics Laboratory (PPPL); Paoletti, F. [Columbia University] [Columbia University; Paul, S. [Princeton Plasma Physics Laboratory (PPPL)] [Princeton Plasma Physics Laboratory (PPPL); Peng, Yueng Kay Martin [ORNL] [ORNL; Ramakrishnan, S. [Princeton Plasma Physics Laboratory (PPPL)] [Princeton Plasma Physics Laboratory (PPPL); Raman, R. [University of Washington, Seattle] [University of Washington, Seattle; Ryan, Philip Michael [ORNL] [ORNL; Sabbagh, S. A. [Columbia University] [Columbia University; Skinner, C. [Princeton Plasma Physics Laboratory (PPPL)] [Princeton Plasma Physics Laboratory (PPPL); Stevenson, T. [Princeton Plasma Physics Laboratory (PPPL)] [Princeton Plasma Physics Laboratory (PPPL); Stutman, D. [Johns Hopkins University] [Johns Hopkins University; Synakowski, E. J. [Princeton Plasma Physics Laboratory (PPPL)] [Princeton Plasma Physics Laboratory (PPPL); Swain, David W [ORNL] [ORNL; Taylor, G. [Princeton Plasma Physics Laboratory (PPPL)] [Princeton Plasma Physics Laboratory (PPPL); Von Halle, A. [Princeton Plasma Physics Laboratory (PPPL)] [Princeton Plasma Physics Laboratory (PPPL); Wilgen, John B [ORNL] [ORNL; Williams, M. [Princeton Plasma Physics Laboratory (PPPL)] [Princeton Plasma Physics Laboratory (PPPL); Wilson, J. R. [Princeton Plasma Physics Laboratory (PPPL)] [Princeton Plasma Physics Laboratory (PPPL); Ackers, R. [EURATOM / UKAEA, UK] [EURATOM / UKAEA, UK; Barry, Robert E [ORNL] [ORNL; Bers, A. [Massachusetts Institute of Technology (MIT)] [Massachusetts Institute of Technology (MIT); Bialek, J. [Columbia University] [Columbia University; Bonoli, P. [Massachusetts Institute of Technology (MIT)] [Massachusetts Institute of Technology (MIT); Carter, Mark Dwain [ORNL] [ORNL; Chrzanowski, J. [Princeton Plasma Physics Laboratory (PPPL)] [Princeton Plasma Physics Laboratory (PPPL); Davis, W. [Princeton Plasma Physics Laboratory (PPPL)] [Princeton Plasma Physics Laboratory (PPPL)

2001-01-01

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

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

31

Experimental rotordynamic coefficient results for honeycomb seals  

NASA Technical Reports Server (NTRS)

Test results (leakage and rotordynamic coefficients) are presented for seven honeycomb-stator smooth-rotor seals. Tests were carried out with air at rotor speeds up to 16,000 cpm and supply pressures up to 8.2 bars. Test results for the seven seals are compared, and the most stable configuration is identified based on the whirl frequency ratio. Results from tests of a smooth-rotor/smooth-stator seal, a teeth-on-stator labyrinth seal, and the most stable honeycomb seal are compared.

Elrod, David A.; Childs, Dara W.

1988-01-01

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

On collisional disruption - Experimental results and scaling laws  

NASA Technical Reports Server (NTRS)

Both homogeneous and inhomogeneous targets have been addressed by the present experimental consideration of the impact strengths, fragment sizes, and fragment velocities generated by cement mortar targets whose crushing strengths vary by an order of magnitude, upon impact of projectiles in the velocity range of 50-5700 m/sec. When combined with additional published data, dynamic impact strength is found to correlate with quasi-static material strengths for materials ranging in character from basalt to ice; two materials not following this trend, however, are weak mortar and clay targets. Values consistent with experimental results are obtainable with a simple scaling algorithm based on impact energy, material properties, and collisional strain rate.

Davis, Donald R.; Ryan, Eileen V.

1990-01-01

34

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

35

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

36

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

37

Liquid hydrogen for automotive vehicles - Experimental results  

SciTech Connect

A BMW-518 has been adapted for LH2-fuel, representing the first LH2-fueled car in Europe. This is a joint program between the German Research and Testing Laboratory for Aeronautics and the Research Institute for Motor-Transport Service and Automotive Engines at the University of Stuttgart. The program was established for demonstration of successful car-operation and and the safe handling of LH2-fuel during car operation and refueling. Based on earlier papers, more recent test results and experiences are reported about car operation and engine performance. The car has been driven over an accumulated distance of about 1800 km on a test track. The test track consists of a loop of about 2.5 km in length, including a proper combination of straight level sections, curved sections and ascending sections. In order to demonstrate a safe liquid hydrogen refueling procedure that could also be used by untrained people, a semiautomatic computer operated refueling station has been developed. This refueling station is in successful operation.

Peschka, W.

1981-01-01

38

Experimental High Energy Neutrino Astrophysics  

SciTech Connect

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

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

2005-10-12

39

Strain Energy During Mechanical Milling: Part II. Experimental  

NASA Astrophysics Data System (ADS)

The strain energy stored in mechanically milled 5083 Al powders was investigated using two experimental approaches: thermal and microstructural analysis. The experimental results show that mechanically milled 5083 Al powders store strain energy on the order of a few tens of joules per gram. These experimental results are consistent with the calculated strain energy stored in mechanically milled powders. The experimentally measured strain energy stored in powders increases with an increase in attritor diameter, impeller's rotational frequency, and ball-to-powder mass ratio; however, it decreases with an increase in ball diameter. These trends were in good agreement with the calculated strain energy stored in powders as a function of the corresponding processing parameters.

Lin, Yaojun; Yao, Bo; Zhang, Zhihui; Li, Ying; Sohn, Yongho; Schoenung, Julie M.; Lavernia, Enrique J.

2012-11-01

40

Blanking and piercing theory, applications and recent experimental results  

NASA Astrophysics Data System (ADS)

Blanking and piercing are manufacturing processes by which certain geometrical shapes are sheared off a sheet metal. If the sheared off part is the one required, the processes referred to as blanking and if the remaining part in the sheet is the one required, the process is referred to as piercing. In this paper, the theory and practice of these processes are reviewed and discussed The main parameters affecting these processes are presented and discussed. These include: the radial clearance percentage, punch and die geometrical parameters, for example punch and die profile radii. The abovementioned parameters on the force and energy required to effect blanking together with their effect on the quality of the products are also presented and discussed. Recent experimental results together with photomacrographs and photomicrographs are also included and discussed. Finally, the effect of punch and die wear on the quality of the blanks is alsogiven and discussed.

Zaid, Adnan l. O.

2014-06-01

41

Alternative Experimental Protocol for a PBR-Like Result  

E-print Network

Pusey, Barrett and Rudolph (PBR) have recently proven an important new theorem in the foundations of quantum mechanics. Here we propose alternative experimental protocols which lead to the PBR result for a special case and a weaker PBR-like result generally. Alternative experimental protocols support the assumption of measurement independence required for the PBR theorem.

D. J. Miller

2012-02-29

42

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

43

1. DARK ENERGY DETECTION: AN EXPERIMENTAL PROBLEM  

E-print Network

The majority of astronomers and physicists accept the reality of dark energy and also believe that it can only be studied indirectly through observation of the motions of stars and galaxies. In this paper I open the experimental question of whether it is possible to directly detect dark energy through the presence of dark energy density. Two thirds of this paper outlines the major aspects of dark energy density as now comprehended by the astronomical and physics community. The final third summarizes various proposals for direct detection of dark energy density or its possible effects. At this time I do not have a

Martin L. Perl

44

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

45

Acoustic analysis in Mudejar-Gothic churches: Experimental results  

NASA Astrophysics Data System (ADS)

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. .

Galindo, Miguel; Zamarreño, Teófilo; Girón, Sara

2005-05-01

46

Experimental results on atomic oxygen corrosion of silver  

NASA Technical Reports Server (NTRS)

The results of an experimental study of the reaction kinetics of silver with atomic oxygen in 10 degree increments over the temperature range of 0 to 70 C is reported. The silver specimens, of the order of 10,000 A in thickness, were prepared by thermal evaporation onto 3 inch diameter polished silicon wafers. There were later sliced into pieces having surface areas of the order of 1/4 to 1/2 square inch. Atomic oxygen was generated by a gas discharge in a commercial plasmod asher operating in the megahertz frequency range. The sample temperature within the chamber was controlled by means of a thermoelectric unit. Exposure of the silver specimens to atomic oxygen was incremental, with oxide film thickness measurements being carried out between exposures by means of an automated ellipsometer. For the early growth phase, the data can be described satisfactorily by a logarithmic growth law: the oxide film thickness increases as the logarithm of the exposure time. Furthermore, the oxidation process is thermally activated, the rate increasing with increasing temperature. However, the empirical activation energy parameter deduced from Arrhenius plots is quite low, being of the order of 0.1 eV.

Fromhold, Albert T.

1988-01-01

47

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 Landeo; Kathryn Spier

2012-01-01

48

Flow Measurement with Tangential Paddlewheel Flow Meters: Analysis of Experimental Results and in-situ Diagnostics  

E-print Network

Proceedings of the 16th Annual Industrial Energy Technology Conference 1994, Houston, TX pp. 252-260 ESL-PA-94/04-02 REPRINTED WITH PERMISSION FLOW MEASUREMENT WITH TANGENTIAL PADDLEWHEEL FLOW METERS: ANALYSIS OF EXPERIMENTAL RESULTS AND IN...-SITU DIAGNOSTICS Jim Watt, Jeff Haberl Energy Systems Laboratory Mechanical Engineering Department Texas A&M University College Station, TX ABSTRACT Flow measurement is an important part of the analysis of building energy use whenever thermal energy use is being...

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

49

Comparison of calculated and experimental results of fragmenting cylinder experiments  

SciTech Connect

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

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

2000-06-02

50

CANDELA PHOTO-INJECTOR EXPERIMENTAL RESULTS WITH A DISPENSER PHOTOCATHODE  

E-print Network

CANDELA PHOTO-INJECTOR EXPERIMENTAL RESULTS WITH A DISPENSER PHOTOCATHODE C. Travier, B. Leblond, M- injector. The dispenser photocathode is illuminated by a 500 fs pulse from a frequency-tripled Ti:sapphire laser. In this paper we report charge measurements showing that the dispenser pho- tocathode has

Paris-Sud XI, Université de

51

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 we derive a dynamical model of a blimp, which is described as nonlinear dynamical equations

52

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.

53

Variable amplitude fatigue crack growth, experimental results and modeling  

E-print Network

the growth of fatigue cracks under complex load spectra. It contains a crack propagation law (da/dt = a Predicting fatigue crack growth in metals under random loadings is a difficult task, in particular becauseVariable amplitude fatigue crack growth, experimental results and modeling R. Hamam a , S. Pommier

54

Nonlinear fundamental photothermal response: experimental results for tungsten  

E-print Network

Nonlinear fundamental photothermal response: experimental results for tungsten A. Salnicka,*, J structures containing a tungsten layer is presented. Two sets of wafers, one with a very rough tungsten overlayer surface and another with a smooth polished tungsten surface have been studied. It is shown

Mandelis, Andreas

55

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

56

Modeling and experimental result analysis for high-power VECSELs  

Microsoft Academic Search

We present a comparison of experimental and microscopically based model results for optically pumped vertical external cavity surface emitting semiconductor lasers. The quantum well gain model is based on a quantitative ab-initio approach that allows calculation of a complex material susceptibility dependence on the wavelength, carrier density and lattice temperature. The gain model is coupled to the macroscopic thermal transport,

Aramais R. Zakharian; Joerg Hader; Jerome V. Moloney; Stephan W. Koch; Stephan Lutgen; Peter Brick; Tony Albrecht; Stefan Grötsch; Johann Luft; Werner Späth

2003-01-01

57

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

58

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

59

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

60

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

61

An Experimental Overview of Results Presented at SQM 2006  

E-print Network

I have been asked to give an critical overview on the experimental results shown in the conference with a emphasis of what has been learned and the challenges that are ahead in trying to understand the physics of the strongly interacting quark-gluon plasma. I will not try to summarize all of the results presented, rather I will concentrate primarily on RHIC data from this conference. Throughout this summary, I will periodically review some of the previous results for those not familiar with the present state of the field.

Richard Seto

2006-06-26

62

Experimental Results and Theoretical Developments of Muon g-2  

E-print Network

The anomalous magnetic moments of both positive and negative muons are measured to the precision of 0.7 parts per million. Two values are in good agreement. The standard model calculations of muon g-2 are under further studies, especially the descrepancies between $e^+e^-$ and $\\tau$ data. The differences between experimental result and the standard model calculations are $2.4\\sigma$ for $e^+e^-$ data and $0.9\\sigma$ for $\\tau$ data.

H. Deng; for Muon g-2 Collaboration

2004-08-31

63

Wavelength modulation photoacoustic spectroscopy: Theoretical description and experimental results  

Microsoft Academic Search

A theoretical description of photoacoustic spectroscopy generated by wavelength modulation of a semiconductor laser source is reported for a Lorentzian absorption line. This model describes the first- and second-harmonic photoacoustic signals produced by a current-modulated semiconductor laser. Combined intensity- and wavelength-modulation is considered with arbitrary phase shift. Experimental results obtained when probing a CO2 absorption line with a 2-?m distributed

Stéphane Schilt; Luc Thévenaz

2006-01-01

64

Mechanical properties of triaxially braided composites: Experimental and analytical results  

NASA Technical Reports Server (NTRS)

This paper investigates the unnotched tensile properties of two-dimensional triaxial braid reinforced composites from both an experimental and analytical viewpoint. 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 readings. Larger strain gages gave more consistent results and correlated better with the extensometer readings. Experimental strains correlated reasonably well with analytical predictions in the longitudinal, zero degree, 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 assistence of computer analysis of the microgeometry. Photomicrographs of the 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

65

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

66

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

67

[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

68

Showing results, 3 Energy technology and energy planning  

E-print Network

techniques for industry ­ Wind energy, 4 Wind turbines, 4 Wind energy systems, 5 Wind resources and wind systems, 10 Energy planning in developing countries, 11 ­ Environmental impact of atmospheric processesShowing results, 3 Energy, 4 Energy technology and energy planning Environment, 12 Environmental

69

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

70

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

71

Results of a high energy gamma telescope  

NASA Astrophysics Data System (ADS)

We report on experimental results obtained using a new type of detector for high energy gamma astrophysics. The apparatus can detect gamma-rays in the GeV range, with an angular resolution of a few mrad and an acceptance of 50°. The telescope is based on the imaging of the Cherenkov light produced in a dense medium (liquid or solid) backed by a parabolic or spherical reflecting surface. The high energy electrons, produced at the start of the electromagnetic shower, generate a ring-shaped photon image which may produce tens or hundreds of photoelectrons on an appropriate photon imaging detector placed at the focal plane of the system on the entrance surface of the converter. A prototype consisting of a liquid radiator (C6F14), a multistep parallel-plate avalanche chamber and an optical readout system has been tested in a 1-10 GeV/c charged particle beam. The analysed data indicate that the initial direction of particles can be reconstructed with an angular resolution of approximatelly 3.5 mrad. Furthermore, the capability of such a detector to separate e/? in the GeV range seems promising. Possible use of the apparatus in a space-borne experiment for distinct gamma-ray sources is also discussed.

Charpak, G.; Giomataris, Y.; Gougas, A.

1994-04-01

72

Experimental Results for Titan Aerobot Thermo-Mechanical Subsystem Development  

NASA Technical Reports Server (NTRS)

This paper presents experimental results on a set of 4 thermo-mechanical research tasks aimed at Titan and Venus aerobots: 1. A cryogenic balloon materials development program culminating in the fabrication and testing of a 4.6 m long blimp prototype at 93K. 2. A combined computational and experimental thermal analysis of the effect of radioisotope power system (RPS) waste heat on the behavior of a helium filled blimp hull. 3. Aerial deployment and inflation testing using a blimp 4. A proof of concept experiment with an aerobot-mounted steerable high gain antenna These tasks were supported with JPL internal R&D funds and executed by JPL engineers with substantial industry collaboration for Task #1, the cryogenic balloon materials

Pauken, Michael T.; Hall, Jeffery L.

2006-01-01

73

Recent experimental results with uranium fragments at the FRS  

NASA Astrophysics Data System (ADS)

New experimental results were obtained with relativistic exotic nuclei produced via uranium projectile fragmentation and projectile fission at the in-flight separator FRS. 60 neutron-rich isotopes have been discovered in the element range from Nd to Ac and their production cross sections have been measured. In other experimental campaigns the fragments were separated in flight and injected into the storage-cooler ring ESR for accurate mass- and lifetime measurements. New mass values have been measured for 33 nuclides in the element range from Pt to U circulating in the ESR. The systematic error has been reduced to about 10 keV which was possible by a new evaluation method.

Geissel, H.

2012-10-01

74

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

75

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

76

Some results of experimental investigations of fire tornadoes  

NASA Astrophysics Data System (ADS)

Results of experimental investigations of liquid fuel combustion in the regime of a twisted jet (model of a fire tornado) are presented. To perform investigations, a stand equipped with measuring devices based on optical and thermal imaging methods has been developed and manufactured. Dependences of the geometrical characteristics, heat flux, combustion rate, and frequencies of maxima in the spectral function of the intensity fluctuations and in the centre of gravity of image of the laser beam that has passed through the tornado on the twist velocity are determined.

Grishin, A. M.; Reino, V. V.; Sazanovich, V. M.; Tsvyk, R. Sh.; Sherstobitov, M. V.

2012-05-01

77

Energy Audit Results for Residential Building Energy Efficiency  

E-print Network

Energy Audit Results for Residential Building Energy Efficiency Forrest City Phases I and II This report analyses complete energy audit results from 28 homes within the Forest City residential complex. Relationships between temperature, humidity, comfort, and energy consumption are detailed. Recommendations

78

Silicon drift detector with reduced lateral diffusion:. experimental results  

NASA Astrophysics Data System (ADS)

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

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

2000-01-01

79

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

80

Experimental Results of Rover-Based Coring and Caching  

NASA Technical Reports Server (NTRS)

Experimental results are presented for experiments performed using a prototype rover-based sample coring and caching system. The system consists of a rotary percussive coring tool on a five degree-of-freedom manipulator arm mounted on a FIDO-class rover and a sample caching subsystem mounted on the rover. Coring and caching experiments were performed in a laboratory setting and in a field test at Mono Lake, California. Rock abrasion experiments using an abrading bit on the coring tool were also performed. The experiments indicate that the sample acquisition and caching architecture is viable for use in a 2018 timeframe Mars caching mission and that rock abrasion using an abrading bit may be feasible in place of a dedicated rock abrasion tool.

Backes, Paul G.; Younse, Paulo; DiCicco, Matthew; Hudson, Nicolas; Collins, Curtis; Allwood, Abigail; Paolini, Robert; Male, Cason; Ma, Jeremy; Steele, Andrew; Conrad, Pamela G.

2011-01-01

81

Object impedance control for cooperative manipulation - Theory and experimental results  

NASA Technical Reports Server (NTRS)

This paper presents the dynamic control module of the Dynamic and Strategic Control of Cooperating Manipulators (DASCCOM) project at Stanford University's Aerospace Robotics Laboratory. First, the cooperative manipulation problem is analyzed from a systems perspective, and the desirable features of a control system for cooperative manipulation are discussed. Next, a control policy is developed that enforces a controlled impedance not of the individual arm endpoints, but of the manipulated object itself. A parallel implementation for a multiprocessor system is presented. The controller fully compensates for the system dynamics and directly controls the object internal forces. Most importantly, it presents a simple, powerful, intuitive interface to higher level strategic control modules. Experimental results from a dual two-link-arm robotic system are used to compare the object impedance controller with other strategies, both for free-motion slews and environmental contact.

Schneider, Stanley A.; Cannon, Robert H., Jr.

1992-01-01

82

The yield strength of subliquidus basalts — experimental results  

NASA Astrophysics Data System (ADS)

Yield strength is an important property of particle-fluid 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 strength-crystallinity relations are poorly known, particularly in geologic suspensions, where difficulties of experimental and field measurements have limited data acquisition in the subliquidus temperature range. Here we describe two complementary experimental approaches designed to examine the effect of particle shape on the low-shear yield strength of subliquidus basalts. The first involves melting cubes of holocrystalline basalt samples with different initial textures to determine the temperature (crystallinity) at which these samples lose their cubic form. These experiments provide information on the minimum crystal volume fractions (0.20< ?<0.35) required to maintain the structual integrity of the cube. The second set of experiments uses suspensions of corn syrup and neutrally buoyant particles to isolate the effect of particle shape on yield strength development. From these experiments, we conclude that the shape is important in determining the volume fraction range over which suspensions exhibit a finite yield strength. As anisotropic particles may orient during flow, the effect of particle shape will be controlled by the orientation distribution of the constituent particles. We find that the so-called 'excluded volume' can be used to relate results of experiments on anisotropic particles to those of suspensions of spherical particles. Recent measurements of yield strength onset in basaltic melts at crystal volume fractions near 0.25 are consistent with our observations that crystal frameworks develop at low to moderate crystal volume fractions when crystals are anisotropic (e.g. plagioclase). We further suggest that conditions leading to yield strength onset at low crystallinities include rapid cooling (increased crystal anisotropy), heterogeneous nucleation (which promotes extensive crystal clustering and large cluster anisotropy) and static conditions (random crystal orientations).

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

2001-06-01

83

Experimental results for Titan aerobot thermo-mechanical subsystem development  

NASA Astrophysics Data System (ADS)

This paper describes experimental results from a development program focused in maturing Titan aerobot technology in the areas of mechanical and thermal subsystems Results from four key activities are described first a cryogenic balloon materials development program involving coupon and cylinder tests and culminating in the fabrication and subsequent testing of an inflated 4 6 m long prototype blimp at 93 K second a combined lab experiment and numerical simulation effort to assess potential problems resulting from radioisotope thermal generator waste heat generation near an inflated blimp third an aerial deployment and inflation development program consisting of laboratory and helicopter drop tests on a near full scale 11 m long prototype blimp and fourth a proof of concept experiment demonstrating the viability of using a mechanically steerable high gain antenna on a floating blimp to perform direct to Earth telecommunications from Titan The paper provides details on all of these successful activities and discusses their impact on the overall effort to produce mature systems technology for future Titan aerobot missions

Hall, J.; Jones, J.; Kerzhanovich, V.; Lachenmeier, T.; Mahr, P.; Pauken, M.; Plett, G.; Smith, L.; van Luvender, M.; Yavrouian, A.

84

Experimental Results for Titan Aerobot Thermo-Mechanical Subsystem Development  

NASA Technical Reports Server (NTRS)

This paper describes experimental results from a development program focused in maturing Titan aerobot technology in the areas of mechanical and thermal subsystems. Results from four key activities are described: first, a cryogenic balloon materials development program involving coupon and cylinder tests and culminating in the fabrication and testing of an inflated 4.6 m long prototype blimp at 93 K; second, a combined lab experiment and numerical simulation effort to assess potential problems resulting from radioisotope thermal generator waste heat generation near an inflated blimp; third, an aerial deployment and inflation development program consisting of laboratory and helicopter drop tests on a near full scale (11 m long) prototype blimp; and fourth, a proof of concept experiment demonstrating the viability of using a mechanically steerable high gain antenna on a floating blimp to perform direct to Earth telecommunications from Titan. The paper provides details on all of these successful activities and discusses their impact on the overall effort to produce mature systems technology for future Titan aerobot missions.

Hall, Jeffrey L.; Jones, J. A.; Kerzhanovich, V. V.; Lachenmeier, T.; Mahr, P.; Pauken, M.; Plett, G. A.; Smith, L.; VanLuvender, M. L.; Yavrouian, A. H.

2006-01-01

85

Experimental results for Titan aerobot thermo-mechanical subsystem development  

NASA Astrophysics Data System (ADS)

This paper describes experimental results from a development program focused on maturing Titan aerobot technology in the areas of mechanical and thermal subsystems. Results from four key activities are described: first, a cryogenic balloon materials development program involving coupon and cylinder tests and culminating in the fabrication and testing of an inflated 4.6 m long prototype blimp at 93 K; second, a combined lab experiment and numerical simulation effort to assess potential problems resulting from radioisotope power source waste heat generation near an inflated blimp; third, an aerial deployment and inflation development program consisting of laboratory and helicopter drop tests on a near full scale (11 m long) prototype blimp; and fourth, a proof of concept experiment demonstrating the viability of using a mechanically steerable high gain antenna on a floating blimp to perform direct to Earth telecommunications from Titan. The paper provides details on all of these successful activities and discusses their impact on the overall effort to produce mature systems technology for future Titan aerobot missions.

Hall, J. L.; Jones, J. A.; Kerzhanovich, V. V.; Lachenmeier, T.; Mahr, P.; Pauken, M.; Plett, G. A.; Smith, L.; van Luvender, M. L.; Yavrouian, A. H.

2008-11-01

86

Experimental results with hydrocarbon mixtures in domestic refrigerator/freezers  

SciTech Connect

With propane/n-butane blends, energy savings up to 6% were achieved in a domestic refrigerator/freezer compared to the baseline test with R-12. The hydrocarbon mixtures were tested as drop-in substitutes. All the hardware remained the same, only the capillary tube was lengthened to control the flow rate. The additional capillary tube length, the blend concentration, and the charge were adjusted to determine the optimum performance. The best result of 2.29 kWh/day was achieved with a blend of 70% R-290 and 30% R-600, 70 g of charge, and an additional capillary tube length of 5 ft.

Liu, B.Y.; Tomasek, M.L.; Radermacher, R. [Univ. of Maryland, College Park, MD (United States). Center for Environmental Energy Engineering

1995-08-01

87

Comparison of IQMD results with experimental data for Sn induced reactions  

E-print Network

Here we are comparing our results with experimental data of reactions 57La124+50Sn124, 50Sn124+50Sn124 and 50Sn107+50Sn124 at energy 600 MeV/nucleon. It is observed that IMF's shows the agreement with data at low impact parameters but fails at intermediate impact parameters. We shall try to reproduce the result with reduced cross-section in future.

Bahadur Singh; Suneel Kumar; Rajeev K. Puri

2010-09-27

88

FRVT 2006 and ICE 2006 large-scale experimental results.  

PubMed

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

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

2010-05-01

89

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

90

Experimental study on a pendulum wave energy converter  

NASA Astrophysics Data System (ADS)

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

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

2013-06-01

91

Experimental study of low-energy charge transfer in nitrogen  

NASA Technical Reports Server (NTRS)

Total charge transfer cross sections were obtained for the N2(+)-N2 system with relative translational ion energies between 9 and 441 eV. Data were obtained to examine the dependence of total cross section on ion energy. The effect of ion excitation on the cross sections was studied by varying the electron ionization energy in the mass spectrometer ion source over an electron energy range between 14.5 and 32.1 eV. The dependence of total cross section on the neutralization chamber gas pressure was examined by obtaining data at pressure values from 9.9 to 0.000199 torr. Cross section values obtained were compared with experimental and theoretical results of other investigations.

Smith, A.

1979-01-01

92

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

NASA Astrophysics Data System (ADS)

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

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

2002-08-01

93

Experimental classical flutter results of a composite advanced turboprop model  

NASA Technical Reports Server (NTRS)

Experimental results are presented that show the effects of blade pitch angle and number of blades on classical flutter of a composite advanced turboprop (propfan) model. An increase in the number of blades on the rotor or the blade pitch angle is destablizing which shows an aerodynamic coupling or cascade effect between blades. The flutter came in suddenly and all blades vibrated at the same frequency but at different amplitudes and with a common predominant phase angle between consecutive blades. This further indicates aerodynamic coupling between blades. The flutter frequency was between the first two blade normal modes, signifying an aerodynamic coupling between the normal modes. Flutter was observed at all blade pitch angles from small to large angles-of-attack of the blades. A strong blade response occurred, for four blades at the two-per-revolution (2P) frequency, when the rotor speed was near the crossing of the flutter mode frequency and the 2P order line. This is because the damping is low near the flutter condition and the interblade phase angle of the flutter mode and the 2P response are the same.

Mehmed, O.; Kaza, K. R. V.

1987-01-01

94

Vortex Dust Flux: Experimental Results Comparing Terrestrial and Martian Cases  

NASA Astrophysics Data System (ADS)

Evidence for active aeolian processes (dunes, windstreaks, ripples, dust storms, and dust devils) on Mars have been observed by Viking, Mars Global Surveyor (MGS), Mars Pathfinder (MPF), and Mars Odyssey. Dust devils on Mars, as on Earth, are seasonally dependent and are very common in some areas, leaving both bright and dark streaks in their wakes demonstrating their ability to modify the surface. Previously, experimental work demonstrated that the dust lifting mechanism, predominantly the pressure drop (? P) in the dust devil core, is more efficient at lifting dust than boundary layer winds. The amount of dust that is lifted via the ? P-mechanism (dust flux) is not well understood for Earth or Mars. This study aims to develop that understanding through experiments with the Arizona State University Vortex Generator (ASUVG) at both Earth-ambient ( ˜1000mb) and Mars ( ˜10mb) conditions using physical analogs for martian dust (particles ˜2? m in diameter). The ASUVG generates dust-devil-like vortices through a motor-driven blade assembly positioned over a configurable test bed. Currently flux experiments have included a removable test plate that rests on an in situ balance used to measure the dust mass loss as a function of time for a ˜5mm-thick bed of dust settled by suspension. Preliminary results have given lower limits on dust devil dust flux for terrestrial ( ˜1-2 g/m2/s) and martian ( ˜2-4 g/m2/s) conditions. Martian conditions yield fluxes that are ˜1.5-2.0 times that of the analogous terrestrial cases. The terrestrial results are comparable to field observations made by Metzger (1999) in Eldorado Valley, NV, demonstrating the validity of using the ASUVG. Future studies intend the usage of optical systems to relate suspended dust opacity to mass in order to expand the range in sizes and speeds of vortices examined.

Neakrase, L. D.; Greeley, R.; Eddlemon, E.; Iversen, J.; Balme, M.; Beardmore, G.

2003-12-01

95

Results from computational and experimental modeling of runaway electron damage on plasma facing components  

SciTech Connect

The purpose of this research was to extend the theoretical and experimental knowledge of runaway electron damage-impact-bombardment on plasma facing components and materials in magnetic fusion devices. The emphasis of this work involved computational modeling and experimental studies to investigate runaway electron energy deposition and thermal response in plasma facing materials. The goals were: (1) to develop a computational model to study and analyze runaway electron damage; (2) to characterize runaway electron parameters; and (3) to perform experiments to analyze runaway electron damage. These goals were accomplished by first assembling the PTA code package. PTA is a unique application of PATRAN, the Integrated TIGER Series (ITS), and ABAQUS for modeling high energy electron impact on magnetic fusion materials and components. The PTA code package provides a three-dimensional, time dependent, computational code package which predicts material response from runaway bombardment under most runaway conditions (i.e., electron energy, incident angle, energy density, and deposition time). As part of this research, PTA was used to study energy deposition and material response in several design applications, to analyze damaged material, and to analyze several experiments. Runaway electron characterization was determined through parametric studies, analysis of damaged materials, and analysis of experimental results. Characterization provided information on electron energy, incident angle, current, deposition time, and volume of material impacted by runaway electrons. Finally an experiment was performed on the Advanced Toroidal Facility (ATF) at Oak Ridge National Laboratory to study runaway electron damage. The experiment provided information on the runaway electron energy and current in ATF, as well as supplemented the existing experimental knowledge of runaway electron damage.

Niemer, K.A. [Westinghouse Savannah River Co., Aiken, SC (United States); Gilligan, J.G. [North Carolina State Univ., Raleigh, NC (United States); Croessmann, C.D. [Sandia National Labs., Albuquerque, NM (United States)

1994-11-01

96

Can plumes collapse?: Experimental results and applications to Iceland.  

NASA Astrophysics Data System (ADS)

Iceland has produced magma in a series of episodic events. From lava chemistry it has been inferred that the plume temperature decreased over the first 5 Myr by ~50°C and for the next 3 Myr following continental break up it continued to oscillate by ~25°C. Such data has been used to infer possible episodic collapse of the Iceland plume. Collapsing plumes are not common fluid dynamical features. In thermochemical plumes it is possible to achieve collapse by varying the relative buoyancy due to chemistry and due to temperature. In thermal plumes however, with a constant heat source we would expect plumes not to collapse but to not continue to rise after reaching a point of neutral buoyancy. We expect thermal plumes, like those Earth's bottom thermal boundary layer is capable of producing, to either rise to the surface or be deflected but not to collapse. We have designed an experimental setup to investigate the conditions that may lead to collapse in thermal plumes with constant heat sources. We used high-Prandtl number fluids with strongly temperature-dependent viscosities (Lyle Golden syrup and Liquidose 436) as analogues to Earth's high viscosity mantle in a cubic Plexiglas tank (26.5cm inner sides), heated by a circular 2cm diameter heater (flat with the base of the tank). We explored ?Ts between 3-60°C. The flow was visualized with shadowgraphs and an automated -3D Stereoscopic Particle Image Velocimetry (SPIV) system to measure velocities. In Lyle's Golden Syrup collapse occurred at ?Ts as high as 8°C, while in Liquidose 436 the 8°C ?T run showed only partial collapse. The difference is not unexpected given the different physical properties. Partial collapse was seen even for ?Ts as high as 50°C. Both complete and partial collapse manifested themselves as downwelling flow in the central part of the conduit. Collapse stopped in the hotter plumes when the downwelling fluid met the hottest part of the conduit. The observed results suggest that diffusive time-scales are faster than the time-scales of buoyant rise. A naïve Rayleigh number analysis suggested that even a ?T as low as 1°C is above Rayleigh critical for the size of the convecting region. We will also present preliminary 3-D velocimetry results. Our results imply a much wider range of fluid dynamical behaviours for thermal plumes, which suggests that the dynamics of Earth plumes is probably not as straight-forward as previously hypothesised.

Pears, M.; Lithgow-Bertelloni, C.

2012-04-01

97

SPS energy scan results and physics prospects at FAIR  

E-print Network

Experimental studies of nucleus-nucleus collisions in the whole SPS energy range are reviewed. Selected topics such as statistical properties of the hadronic phase, strangeness production, fluctuations and correlations are discussed with regard to information on the onset of deconfinement and the critical point of strongly interacting matter. In spite of the very interesting results obtained in particular at the low SPS energies, additional data including rare probes such as charmed particles and di-leptons are required for a precise understanding of the underlying physics. An outlook about prospects and capabilities of upcoming experiments in this interesting energy region at RHIC, SPS, and in particular with CBM at FAIR, is given.

C. Hohne

2009-09-25

98

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

99

New experimental results on neutrino mixing and decay.  

NASA Astrophysics Data System (ADS)

The search for neutrino decay is a sensitive method to look for very small neutrino mixing parameter. The authors report about the status of an decay experiment performed at a reactor in Bugey and present preliminary new experimental limits on the coupling of a heavy neutrino to the electron state. Additionally new experimental lifetime bounds on the radiative decay mode are given. Rigid laboratory limits on this decay mode for the hypothetical 17 keV neutrino are presented. Limits on the radiative decay of a 17 keV neutrino obtained from the supernova SN 1987A are discussed.

Oberauer, L.; von Feilitzsch, F.; Hagner, C.; Kempf, G.; Mößbauer, R. L.; Declais, Y.; Kajfasz, E.

100

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

101

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

102

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. Á.; Santonja, C.; Domingo, M.

2014-06-01

103

Compaction of lithic sands: Experimental results and applications  

SciTech Connect

Compaction experiments showed that the degree of physical compaction of a lithic sand is related to the amount and type of lithic material present. Physical compaction models were developed based on experimental data from well-sorted lithic sandstones for which the percentage of preserved porosities were functions of the effective stress, the type of lithic material, and the quantity of lithic material. These models are derived from laboratory sandstones with at least 25% lithic grains in the following categories: moderately ductile metamorphic lithic fragments, highly ductile shale lithic fragments, and extremely ductile altered volcanic lithic fragments. Application of the compaction models of the experimental compaction techniques to modern subsurface sand samples (or outcrop equivalents) can provide valuable estimates of the preserved porosities (i.e., reservoir potential) for lithic sandstones that may be exploratory objectives in frontier basins. Examples using the models and experimental compaction techniques for exploration are given. Experimental data showed that precompaction cement and overpressure may be beneficial to porosity preservation. An early formed partial cement can retard compaction and preserve porosity by stabilizing the sand pack. A later cement does not have this beneficial effect. Overpressure, when developed early, retards compaction by reducing the effective stress. Of course, a late-developing overpressure is not effective at preserving porosity because compaction is an irreversible process.

Pittman, E.D.; Larese, R.E. (Amoco Production Co., Tulsa, OK (United States))

1991-08-01

104

Experimental determination of ice sublimation energies  

NASA Astrophysics Data System (ADS)

In Astrophysics, the study of ices is important due to the wide range of scenarios in which they are present. Their physical and chemical characteristics play an important role in the study of the interstellar medium (ISM). The assessment of the energy of sublimation allows us to improve our understanding of physical and/or chemical processes that take place where ices are present. The energy of sublimation E_sub is defined as the change of energy between solid and gas phase of certain molecule. This value is important to determinate other thermodynamical parameters such as the reticular energy of ionic compounds, the energy of formation in gas phase from the energy of formation in condensed phase, or to estimate the sublimation rate, which is very important in determining the evolution of surfaces of astrophysical objects.

Luna, R.; Canto, J.; Satorre, M. A.; Domingo, M.

2011-11-01

105

Detritiation of water by isotopic exchange. Experimental results  

SciTech Connect

This paper presents new experimental data on a simple, low-cost vapor-sparging technique using the process of isotopic exchange, which capitalizes on the isotopic disequilibrium between a tritiated wastewater and a tritium free, water-saturated vapor. Isotopic equilibrium was observed between the tritiated water and exhaust vapors for tritium as well as for deuterium and oxygen-18 within 1-2 s (over a 20-cm bubble rise). This steady-state equilibrium provides maximum efficiency in reducing the tritium concentrations by isotopic exchange. About 50% of the initial tritium activity (either 5000 or 630 000 TU) of a tritated water was transferred to the vapor phase over an average of 45 days. Exchange rates analysis for all isotopes studied indicates that for a given experimental geometry and isotopic equilibrium the factors controlling the magnitude of the exchange are the absolute humidity and the flow rate of the tritium-free airstream. 17 refs., 5 figs.

Slattery, M.W.; Ingraham, N.L. (Univ. of Nevada System, Las Vegas, NV (United States))

1994-08-01

106

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

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

Adaptive iterative learning control for robot manipulators: Experimental results  

Microsoft Academic Search

In this paper, two adaptive iterative learning control schemes, proposed by A. Tayebi [2004, Automatica, 40(7), 1195–1203], are tested experimentally on a five-degrees-of-freedom (5-DOF) robot manipulator CATALYST5. The control strategy consists of using a classical PD feedback structure plus an additional iteratively updated term designed to cope with the unknown parameters and disturbances. The control implementation is very simple in

A. Tayebi; S. Islam

2006-01-01

109

Energy Monitoring--Objectives vs Results  

E-print Network

ENERGY MONITORING -- OBJECTIVES VS RESULTS R. M. McEver, Jr. ENGINEERING MEASUREMENTS COMPANY Houston, INTRODUCTION Universities, hospitals and similar institutions, as well as manufacturers and plants have implemented programs of utility... expectations. Most of the programs are continuing in an expanding mode. Results of improvements to the uti! ity distribution system can be measured in reduced usage and improved efficiency after submetering is in place. Networking of this monitoring...

McEver, R. M. Jr.

110

Laser ablation of a turbid medium: Modeling and experimental results  

SciTech Connect

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

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

2006-08-01

111

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.

1993-01-01

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

JFIT: a framework to obtain combined experimental results through joint fits  

E-print Network

A framework is presented for obtaining combined experimental results through joint fits of datasets from several experiments. The JFIT framework allows such fits to be performed keeping the data separated, in its original format, and using independent fitting environments, thus simplifying the process with respect to data access policies. It is based on a master-server architecture, using the network communication classes from ROOT. The framework provides an optimal way to exploit data from several experiments: it ensures that correlations are correctly taken into account and results in a better determination of nuisance parameters. Its advantages are discussed and illustrated by two examples from the domain of high energy physics.

Eli Ben-Haim; René Brun; Bertrand Echenard; Thomas E. Latham

2014-09-17

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

Experimental results for a microscale ethanol vapor jet ejector  

NASA Astrophysics Data System (ADS)

A microscale jet ejector driven by ethanol vapor is designed and tested to induce a suction draft using a supersonic converging-diverging micronozzle. A three-dimensional axisymmetric nozzle is fabricated using electro-discharge machining to produce a throat diameter of 187 µm with an expansion ratio of 3:1. The motive nozzle achieves a design mass flow efficiency of 93% compared to isentropic calculations. Two different ejector area ratios are compared using ethanol vapor and nitrogen gas separately to motivate and entrain ambient air. The experimental data indicate that the ejector can produce a sufficient suction draft to satisfy both microengine mass flow and power off-take requirements to enable its substitution for high-speed microscale pumping turbomachinery.

Gardner, W. G.; Jaworski, J. W.; Camacho, A. P.; Protz, J. M.

2010-04-01

116

Results from STAR Beam Energy Scan Program  

E-print Network

Results from the Beam Energy Scan (BES) program conducted recently 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-o?ff" of strongly inter- acting 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 Sumbera

2013-01-31

117

Simulation of Differential Interferometry and Comparison with Experimental Results  

E-print Network

phenomenon can be adapted until it closely fits the result of the physical experiment. The use of computer is the so­called Mach­Zehnder Interferome­ ter. It utilizes the variation of the index of refraction accumulates indices of refraction along a light beam passing through a medium, the resulting interferogram

118

Experimental test results of a generalized parameter fuel control  

NASA Technical Reports Server (NTRS)

Considerable interest has been generated recently in low cost jet propulsion systems. One of the more complicated components of jet engines is the fuel control. Results of an effort to develop a simpler hydromechanical fuel control are presented. This prototype fuel control was installed on a J85-GE-13 jet engine. Results show that the fuel control provided satisfactory engine performance at sea level static conditions over its normal nonafterburning operating range, including startup. Results of both bench and engine tests are presented; the difficulties encountered are described.

Batterton, P. G.; Gold, H.

1973-01-01

119

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; Márquez-Sánchez, C; Marcelino-Aranda, M; Marciano-Melchor, M; Silva-Ortigoza, G; Bautista-Quintero, R; Ramos-Silvestre, E R; Rivera-Díaz, J C; Muñoz-Carrillo, D

2013-01-01

120

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

121

Waste glass corrosion modeling: Comparison with experimental results  

SciTech Connect

A chemical model of glass corrosion will be used to predict the rates of release of radionuclides from borosilicate glass waste forms in high-level waste repositories. The model will be used both to calculate the rate of degradation of the glass, and also to predict the effects of chemical interactions between the glass and repository materials such as spent fuel, canister and container materials, backfill, cements, grouts, and others. Coupling between the degradation processes affecting all these materials is expected. Models for borosilicate glass dissolution must account for the processes of (1) kinetically-controlled network dissolution, (2) precipitation of secondary phases, (3) ion exchange, (4) rate-limiting diffusive transport of silica through a hydrous surface reaction layer, and (5) specific glass surface interactions with dissolved cations and anions. Current long-term corrosion models for borosilicate glass employ a rate equation consistent with transition state theory embodied in a geochemical reaction-path modeling program that calculates aqueous phase speciation and mineral precipitation/dissolution. These models are currently under development. Future experimental and modeling work to better quantify the rate-controlling processes and validate these models are necessary before the models can be used in repository performance assessment calculations.

Bourcier, W.L.

1993-11-01

122

EXPERIMENTAL RESULTS FROM A MICROWAVE CAVITY BEAM POSITION MONITOR.  

SciTech Connect

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

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

1999-03-29

123

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.; Márquez-Sánchez, C.; Marcelino-Aranda, M.; Marciano-Melchor, M.; Silva-Ortigoza, G.; Bautista-Quintero, R.; Ramos-Silvestre, E. R.; Rivera-Díaz, J. C.; Muñoz-Carrillo, D.

2013-01-01

124

Experimental results with hydrogen fueled internal combustion engines  

NASA Technical Reports Server (NTRS)

The paper focuses on the most important experimental findings for hydrogen-fueled internal combustion engines, with particular reference to the application of these findings to the assessment of the potential of hydrogen engines. Emphasis is on the various tradeoffs that can be made, such as between maximum efficiency, maximum power, and minimum NO emissions. The various possibilities for induction and ignition are described. Some projections are made about areas in which hydrogen engines may find their initial application and about optimum ways to design such engines. It is shown that hydrogen-fueled reciprocal internal combustion engines offer important advantages with respect to thermal efficiency and exhaust emissions. Problems arising from preignition can suitably be avoided by restricting the fuel-air equivalence ratio to values below about 0.5. The direct cylinder injection appears to be a very attractive way to operate the engine, because it combines a wide range of possible power outputs with a high thermal efficiency and very low NO emissions at part loads.

De Boer, P. C. T.; Mclean, W. J.; Homan, H. S.

1975-01-01

125

Control of queues with MAP servers: experimental results  

E-print Network

time (waiting time + service time) in this work. As results we report some surprising optimal policies server selection. We focus on the analysis of M/MAP(k)/n queues, where customers arrive to a queuing

Telek, Miklós

126

Experimental results from a network-assisted PID controller  

SciTech Connect

The results presented here are a continuation of studies on a neural-network-based controller. Part 1 is a summary of the previous studies, and Part 2 presents new results and offers some novel techniques used for training the network and making the entire package easier to use. The two major additions are (1) efficient use of training data for dramatically reducing memory requirements and (2) incorporation of a PID algorithm for performing control during training periods.

Curtiss, P.S. [Univ. of Colorado, Boulder, CO (United States). Joint Center for Energy Management

1996-11-01

127

Experimental results of USSR nuclear explosion decoupling measurements  

SciTech Connect

This report was presented at the 14th annual PL/DARPA Seismic Research Symposium on September 16, 1992. In it, we describe a decoupling experiment undertaken by the former Soviet Union at Azghir, north of the Caspian Sea. The properties of the cavity are given, including a rough description of the geology (salt-dome overlain by 275 m radius sphere, 987 m deep), velocities, densities, etc. These shots had larger yields than the Salmon-Sterling decoupling experiments undertaken by the U.S. in the mid-sixties. Like the U.S. experiment, this Soviet experiment did not achieve full decoupling. The energy decoupling factor (computed from statistical relationships between the yield and amplitude-distance curves rather than spectra) increased to a maximum of 30 as distance increase. Based on our observations and theoretical limits to decoupling, we conclude that a fully decoupled 1 kt explosion could be observed at a distance of 2,500 km.

Adushkin, V.V.; Kitov, I.O.; Sultanov, D.D.

1992-09-01

128

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

129

Experimental investigations on energy harvesting performance of dielectric elastomers  

NASA Astrophysics Data System (ADS)

In this paper, the emerging technology of energy harvesting based on dielectric elastomers (DE), a new type of functional materials belonging to the family of Electroactive Polymers (EAPs), is presented with emphasis on its performance characteristics and some key influencing factors. At first, on the basic principle of DE energy harvesting, the effects of some control parameters are theoretically analyzed under certain mechanical and electrical constraints. Then, a type of annular DE generator using the commercial elastomers of VHB 4910 (3M, USA), is specially designed and fabricated. A series of experimental tests for the device's energy harvesting performance are implemented at different pre-stretch ratios, stretch amplitudes (displacements), and bias voltages in the constant charge (open-circuit) condition. The experiment results demonstrate the associated influence laws of the above control parameters on the performance of the DE generator, and have good consistent with those obtained from the theoretical analysis. This study is expected to provide a helpful guidance for the design and operation of practical DE energy harvesting devices/systems.

Wang, Yongquan; Liu, Xuejing; Xue, Huanhuan; Chen, Hualing; Jia, Shuhai

2014-03-01

130

Electrodynamic magnetic suspension-models, scaling laws, and experimental results  

Microsoft Academic Search

A simple experiment illustrating the principles of electrodynamic magnetic suspension is described and test results are given. A disk-shaped coil made of insulated copper magnet wire and energized with 60 Hz AC line voltage is levitated in a stable equilibrium position above a wide aluminum plate. The mechanisms generating levitation force are identified by the use of Maxwell's equations. A

Marc T. Thompson

2000-01-01

131

Qualitative versus Quantitative Results: An Experimental Introduction to Data Interpretation.  

ERIC Educational Resources Information Center

Described is an experiment in which the student can ascertain the meaning of a negative result from a qualitative test by performing a more sensitive quantitative test on the same sample. Methodology for testing urinary glucose with a spectrophotometer at 630 nm and with commercial assaying glucose strips is presented. (MVL)

Johnson, Eric R.; Alter, Paula

1989-01-01

132

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

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

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

135

Experimental test accelerator: description and results of initial experiments  

SciTech Connect

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

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

1980-06-02

136

Experimental Results of Guided Wave Travel Time Tomography  

NASA Astrophysics Data System (ADS)

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

Volker, Arno; Bloom, Joost

2011-06-01

137

Acceleration and torque feedback for robotic control - Experimental results  

NASA Technical Reports Server (NTRS)

Gross motion control of robotic manipulators typically requires significant on-line computations to compensate for nonlinear dynamics due to gravity, Coriolis, centripetal, and friction nonlinearities. One controller proposed by Luo and Saridis avoids these computations by feeding back joint acceleration and torque. This study implements the controller on a Puma 600 robotic manipulator. Joint acceleration measurement is obtained by measuring linear accelerations of each joint, and deriving a computationally efficient transformation from the linear measurements to the angular accelerations. Torque feedback is obtained by using the previous torque sent to the joints. The implementation has stability problems on the Puma 600 due to the extremely high gains inherent in the feedback structure. Since these high gains excite frequency modes in the Puma 600, the algorithm is modified to decrease the gain inherent in the feedback structure. The resulting compensator is stable and insensitive to high frequency unmodeled dynamics. Moreover, a second compensator is proposed which uses acceleration and torque feedback, but still allows nonlinear terms to be fed forward. Thus, by feeding the increment in the easily calculated gravity terms forward, improved responses are obtained. Both proposed compensators are implemented, and the real time results are compared to those obtained with the computed torque algorithm.

Mclnroy, John E.; Saridis, George N.

1990-01-01

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

Wide-field Fizeau imaging telescope: experimental results.  

PubMed

A nine-aperture, wide-field Fizeau imaging telescope has been built at the Lockheed-Martin Advanced Technology Center. The telescope consists of nine, 125 mm diameter collector telescopes coherently phased and combined to form a diffraction-limited image with a resolution that is consistent with the 610 mm diameter of the telescope. The phased field of view of the array is 1 murad. The measured rms wavefront error is 0.08 waves rms at 635 nm. The telescope is actively controlled to correct for tilt and phasing errors. The control sensing technique is the method known as phase diversity, which extracts wavefront information from a pair of focused and defocused images. The optical design of the telescope and typical performance results are described. PMID:16778931

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

2006-06-20

140

Correlation between analytical and experimental results for propagation buckling  

SciTech Connect

Pipelines are subjected to local damage due to accidental load caused by impact of heavy objects such as equipment dropping from the platforms or anchors. In addition, lost of axial tension during installation and irregularities on the seafloor also induce local damage in pipelines which can lead to buckling initiation. Laboratory tests have been conducted using aluminum and steel small scale models of pipelines with diameter to thickness ratios typical for deepwater applications to determine the minimum pressure to sustain the propagation buckling. Formulae available in the literature for propagation pressure in pipelines have been selected and a correlation study has been performed in order to compare the results from analytical formulae and laboratory tests. Statistical parameters have been used to indicate the most reliable formulae. Sensitivity studies for actual pipelines have been then performed using reliability techniques.

Estefen, S.F.; Aguiar, L.A.D. [Federal Univ. of Rio de Janeiro (Brazil). Ocean Engineering Dept.; Alves, T.M.J. [Petrobras S.A., Rio de Janeiro (Brazil)

1996-12-01

141

Experimental results on microwave pulse compression using helically corrugated waveguide  

NASA Astrophysics Data System (ADS)

The paper presents new results on the development of a method to generate ultrahigh-power short-microwave pulses by using a known principle of compression (reduction in pulse duration accompanying with increase in pulse amplitude) of a frequency-swept wave packet propagating through a dispersive medium. An oversized circular waveguide with helical-corrugations of its inner surface ensures an eigenwave with strongly frequency dependent group velocity far from cutoff. These dispersive properties in conjunction with high rf breakdown strength and low Ohmic losses make a helically corrugated waveguide attractive for increasing microwave peak power. The experiments performed at kilowatt power levels, demonstrate that an X-band microwave pulse of 80 ns duration with a 5% frequency sweep can be compressed into a 1.5 ns pulse having 25 times higher peak power by optimizing the frequency modulation of the input wave packet.

McStravick, M.; Samsonov, S. V.; Ronald, K.; Mishakin, S. V.; He, W.; Denisov, G. G.; Whyte, C. G.; Bratman, V. L.; Cross, A. W.; Young, A. R.; MacInnes, P.; Robertson, C. W.; Phelps, A. D. R.

2010-09-01

142

Longitudinal variation of the equatorial ionosphere: Modeling and experimental results  

NASA Astrophysics Data System (ADS)

We describe a new version of the Parameterized Regional Ionospheric Model (PARIM) which has been modified to include the longitudinal dependences. This model has been reconstructed using multidimensional Fourier series. To validate PARIM results, the South America maps of critical frequencies for the E (foE) and F (foF2) regions were compared with the values calculated by Sheffield Plasmasphere-Ionosphere Model (SUPIM) and IRI representations. PARIM presents very good results, the general characteristics of both regions, mainly the presence of the equatorial ionization anomaly, were well reproduced for equinoctial conditions of solar minimum and maximum. The values of foF2 and hmF2 recorded over Jicamarca (12°S; 77°W; dip lat. 1°N; mag. declination 0.3°) and sites of the conjugate point equatorial experiment (COPEX) campaign Boa Vista (2.8°N; 60.7°W; dip lat. 11.4°; mag. declination -13.1°), Cachimbo (9.5°S; 54.8°W; dip lat. -1.8°; mag. declination -15.5°), and Campo Grande (20.4°S; 54.6°W; dip lat. -11.1°; mag. declination -14.0°) have been used in this work. foF2 calculated by PARIM show good agreement with the observations, except during morning over Boa Vista and midnight-morning over Campo Grande. Some discrepancies were also found for the F-region peak height (hmF2) near the geomagnetic equator during times of F3 layer occurrences. IRI has underestimated both foF2 and hmF2 over equatorial and low latitude sectors during evening-nighttimes, except for Jicamarca where foF2 values were overestimated.

Souza, J. R.; Asevedo, W. D.; dos Santos, P. C. P.; Petry, A.; Bailey, G. J.; Batista, I. S.; Abdu, M. A.

2013-02-01

143

Dust Devils: Experimental Results for Vortex Sediment Flux  

NASA Astrophysics Data System (ADS)

Laboratory experiments using the Arizona State University Vortex Generator ("dust devil machine") yield new results in simulating the amount of sand and dust (flux) raised by dust devils. Flux experiments involved measuring mass loss from a test bed as a function of time for known vortex parameters yielding a calculated value for the flux. Sediment fluxes of dust (2 ? m in diameter), silica sands (5 sizes ranging in diameter from 90 to 500 ? m), and walnut shells (2 sizes ranging in diameter from 590 to 1700 ? m) are compared to the Reynold's number, u{? r{? }/? } (4000-18,000), and a dimensionless lifting parameter, ? P/(? pgDp), (0.001-1.0), in which u{? } and r{? } are the vortex tangential velocity and core radius, ? is the kinematic viscosity of the air, ? P is the pressure drop across the vortex, ? p and Dp are the particle density and diameter, and g is gravitational acceleration. Results show that in general, flux increases with Reynold's number and with lifting parameter. Lower-density walnut shells show a higher flux than silica sands and dust suggesting that on Mars (where g is lower) the flux would be greater in comparison to Earth. Lower-density walnut shell particles are used to simulate the lower g of Mars. Future work involves further expansion of the experiment matrix with other materials of varying sizes and densities. Use of the Mars Surface Wind Tunnel facility at NASA Ames Research Center will also allow this study to be simulated at Mars atmospheric pressures.

Neakrase, L. D.; Greeley, R.; Iversen, J. D.; Balme, M. L.; Foley, D. J.; Eddlemon, E. E.

2004-12-01

144

Experimental determinations of electron stopping power at low energies  

Microsoft Academic Search

An accurate knowledge of electron stopping power is important for calculations and simulations of electron beam interactions with solids especially in the low energy region (< 10 keV). This paper describes a simplified and rapid experimental procedure using based on electron energy loss spectroscopy which permits accurate stopping power determinations to be made from any material which can be observed

Suicho Luo; Xiao Zhang; David C. Joy

1991-01-01

145

Bridge Testing With Ground-Based Interferometric Radar: Experimental Results  

NASA Astrophysics Data System (ADS)

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

Chiara, P.; Morelli, A.

2010-05-01

146

Bridge Testing With Ground-Based Interferometric Radar: Experimental Results  

SciTech Connect

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

Chiara, P.; Morelli, A. [SO.IN.G Strutture e Ambiente S.r.l., Via delle Corallaie 24/4, Livorno (Italy)

2010-05-28

147

Impact ejecta dynamics in an atmosphere - Experimental results and extrapolations  

NASA Technical Reports Server (NTRS)

It is noted that the impacts of 0.635-cm aluminum projectiles at 6 km/sec into fine pumice dust, at 1 atm, generate a ball of ionized gas behind an expanding curtain of upward moving ejecta. The gas ball forms a toroid which dissolves as it is driven along the interior of the ejecta curtain, by contrast to near-surface explosions in which a fireball envelops early-time crater growth. High frame rate Schlieren photographs show that the atmosphere at the base of the ejecta curtain is initially turbulent, but later forms a vortex. These experiments suggest that although small size ejecta may be decelerated by air drag, they are not simply lofted and suspended but become incorporated in an ejecta cloud that is controlled by air flow which is produced by the response of the atmosphere to the impact. The extrapolation of these results to large body impacts on the earth suggests such contrasts with laboratory experiments as a large quantity of impact-generated vapor, the supersonic advance of the ejecta curtain, the lessened effect of air drag due to the tenuous upper atmosphere, and the role of secondary cratering.

Schultz, P. H.; Gault, D. E.

1982-01-01

148

The experimental results and analysis of a borehole radar prototype  

NASA Astrophysics Data System (ADS)

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

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

2012-04-01

149

Experimental results of tri-axial HTS cable  

NASA Astrophysics Data System (ADS)

Recently, a tri-axial cable composed of three concentric phases has been intensively developed, because it has advantages such as reduced high-temperature superconducting (HTS) tape, small leakage field and small heat loss as compared to three single-phase cables. However, there is an inherent imbalance in the three-phase currents in tri-axial cables due to the differences in the radii of the three-phase current layers. The imbalance of the currents causes additional loss and a large leakage field in the cable, and deteriorates the electric power quality. We have already proposed that it is possible to obtain a balanced three-phase distribution by adjusting all of the twist pitches. In order to verify the theory, we designed and fabricated a 1-m-long tri-axial HTS cable and carried out the cable test. The balanced three-phase voltages of the cable were measured by supplying an AC transport current with frequency from 50 to 500 Hz at 77 K. It is found from the test results that the balanced three-phase distributions can be realized by adjusting all of the twist pitches.

Shimoyama, Kazuki; Ozcivan, Nuri; Soeda, Seiji; Hu, Nannan; Onoe, Yuichi; Yagai, Tsuyoshi; Tsuda, Makoto; Hamajima, Takataro

2009-08-01

150

Modeling and experimental characterization of a fluttering windbelt for energy harvesting  

NASA Astrophysics Data System (ADS)

Wind energy harvesters based on fluttering offer a valuable and efficient alternative to the traditional wind turbines. A longer life expectancy and cheaper fabrication is attained through the absence of gears or bearings. This article presents the theoretical and experimental study of a novel windbelt-based energy harvester, designed to harvest from continuously changing low-speed winds. A theoretical model is derived to explore the scaling effect on the critical flutter frequency, and experimental results validate the theoretical predictions.

Arroyo, E.; Foong, S.; Wood, K. L.

2014-11-01

151

Ultrahigh-Energy Cosmic Rays: Results and Prospects  

NASA Astrophysics Data System (ADS)

Observations of cosmic rays have been improved at all energies, both in terms of higher statistics and reduced systematics. As a result, the all-particle cosmic ray energy spectrum starts to exhibit more structures than could be seen previously. Most importantly, a second knee in the cosmic ray spectrum—dominated by heavy primaries—is reported just below 1017 eV. The light component, on the other hand, exhibits an ankle-like feature above 1017 eV and starts to dominate the flux at the ankle. The key question at the highest energies is about the origin of the flux suppression observed at energies above 5 · 1019 eV. Is this the long-awaited Greisen-Zatsepin-Kuzmin effect or the exhaustion of sources? The key to answering this question is again given by the still largely unknown mass composition at the highest energies. Data from different observatories do not quite agree, and common efforts have been started to settle that question. The high level of isotropy observed even at the highest energies starts to challenge a proton-dominated composition if extragalactic magnetic fields are on the order of a few nanogauss or more. We shall discuss the experimental and theoretical progress in the field and the prospects for the next decade.

Kampert, Karl-Heinz

2013-12-01

152

Experimental verification of Santilli`s clean, subnuclear, hadronic energy  

SciTech Connect

The structure of the nucleus and its constituents still presents a challenge to both theoretical and experimental physicists. This paper deals mainly with the an experimental attempt for the verification of the new theory for neutron structure and its stimulated decay recently proposed by R.M. Santilli which would imply a new, clean, subnuclear energy. The experiment is carried out by the Laboratory of Nuclear Technology at the University of Thrace, Xanthi, Greece.

Tsagas, N.F.; Mystakidis, A.; Bakos, G. [Democritus Univ. of Thrace, Xanthi (Greece)] [and others

1996-02-01

153

An Experimental Investigation of the Droplet Deformation Process Resulting from Binary Collisions of a Viscous Fluid  

NASA Astrophysics Data System (ADS)

An experimental investigation of the collisional dynamics of equal sized drops of a viscous, silicone based oil, DC 200, has been conducted for head-on impacts in a vacuum. Results show that the range of droplet Weber numbers necessary to describe the boundaries between permanent coalescence and what has been previously described as reflexive separation, is several orders of magnitude higher than has been reported in studies involving water and hydrocarbon fuel droplets. Energy dissipation during the deformation process has been measured, and the results show a wide discrepancy with available theory. Detailed observations of the post-impact deformation process reveals that in this case, the formation of multiple drops is due solely to the growth of Rayleigh instabilities on the extended fluid ligament.

Willis, Keeney; Orme, Melissa

1997-11-01

154

Experimental and theoretical research in high energy astrophysics  

NASA Technical Reports Server (NTRS)

NASA grants to MIT for investigations in experimental and theoretical high energy astrophysics have, over the years, nurtured the infrastructure development and experimental activities that have led to successful proposals for the OSO 7, SAS 3, HEAO 1, and HEAO 2 missions and to the achievements in high energy astrophysics of the MIT Group. This report consists of excerpts from the progress reports of 1988 through 1990 that have been submitted as a regular feature of the renewal requests. These excerpts convey the flavor of the grant-supported activities, and a sense of the progress that has been made in each of the areas investigations.

Clark, George W.

1990-01-01

155

Recent experimental results on the beam-beam effects in storage rings and an attempt of their interpretation  

SciTech Connect

The latest available experimental results on the luminosity, the space charge parameters, and the beam blowup as functions of particle energy and beam current are reviewed. The comparison with the phenomenological diffusion theory is done and useful scaling laws are derived. Some implications for anti p p storage rings are discussed.

Kheifets, S.

1980-06-01

156

Energy Monitoring in Gins - 2012 Preliminary Results  

Technology Transfer Automated Retrieval System (TEKTRAN)

Electricity and fuel are the second largest source of variable costs for cotton gins, after labor. Few studies of gin energy use have been conducted recently and none have monitored energy use continuously throughout the ginning season. More detailed information is needed to identify management st...

157

Experimental results of two stage harmonic generation with picosecond pulses on the Stanford Mark III FEL  

NASA Astrophysics Data System (ADS)

We report experimental results on upper harmonic conversion using a lithium niobate and a beta barium borate crystal to quadruple the FEL light up into the visible and near infrared. The effects of finite linewidth, birefingent walk-off, and group velocity walk-off on conversion efficiency will be discussed with reference to the experimental results.

Hooper, Brett A.; Benson, Stephen V.; Cutolo, Antonello; Madey, John M. J.

1988-10-01

158

Experimental results of two stage harmonic generation with picosecond pulses on the Stanford Mark III FEL  

Microsoft Academic Search

We report experimental results on upper harmonic conversion using a lithium niobate and a beta barium borate crystal to quadruple the FEL light up into the visible and near infrared. The effects of finite linewidth, birefingent walk-off, and group velocity walk-off on conversion efficiency will be discussed with reference to the experimental results.

Brett A. Hooper; Stephen V. Benson; Antonello Cutolo; John M. J. Madey

1988-01-01

159

Transient excitation of an antenna with a nonlinear load: Numerical and experimental results  

Microsoft Academic Search

A comparison of numerical and experimental results for the current flowing into a nonlinear diode load attached to the terminals of a receiving antenna for transient excitation is presented. It is shown that a simple nonlinear resistive model for the diode is not sufficient to obtain good agreement between the theoretical and experimental results. The diode model and numerical analysis

T. Liu; F. Tesche; F. Deadrick

1977-01-01

160

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

Microsoft Academic Search

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

Alfredo Iranzo; Miguel Muñoz; Felipe Rosa; Javier Pino

2010-01-01

161

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

SciTech Connect

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

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

2005-05-24

162

Comparison of CFD and experimental performance results of a variable area ratio steam ejector  

Microsoft Academic Search

The advantages of numerical modelling compared with experimental studies (e.g. reduced cost, easy control of the variables, high yield etc.) are well known. Theoretical studies where experimental validation is also presented provide an important added value to numerical investigations. In the present paper, experimental and computational fluid dynamics (CFD) results for a 5-kW-rated capacity steam ejector, with a variable primary

Szabolcs Varga; Armando C. Oliveira; Xiaoli Ma; Siddig A. Omer; Wei Zhang; Saffa B. Riffat

2010-01-01

163

Comparative studies on shielding properties of some steel alloys using Geant4, MCNP, WinXCOM and experimental results  

NASA Astrophysics Data System (ADS)

The mass attenuation coefficients, ?/? and effective atomic numbers, Zeff of some carbon steel and stainless steel alloys have been calculated by using Geant4, MCNP simulation codes for different gamma ray energies, 279.1 keV, 661.6 keV, 662 keV, 1115.5 keV, 1173 keV and 1332 keV. The simulation results of Zeff using Geant4 and MCNP codes have been compared with possible available experimental results and theoretical WinXcom, and good agreement has been observed. The simulated ?/? and Zeff values using Geant4 and MCNP code signifies that both the simulation process can be followed to determine the gamma ray interaction properties of the alloys for energies wherever analogous experimental results may not be available. This kind of studies can be used for various applications such as for radiation dosimetry, medical and radiation shielding.

Singh, Vishwanath P.; Medhat, M. E.; Shirmardi, S. P.

2015-01-01

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

Experimental results from the HDL orotron - A tunable source of coherent millimeter wave radiation  

Microsoft Academic Search

The present investigation is concerned with recent experimental results obtained from the Harry Diamond Laboratories (HDL) orotron, a free electron laser (FEL). A description is provided of experimental observations of orotron oscillations. In the HDL orotron a 0.3 mm x 10.0 mm electron beam passes over and interacts with a copper reflecting diffraction grating. This grating is imbedded in a

H. Dropkin; R. P. Leavitt; D. E. Wortman

1982-01-01

166

Single-phase convective heat transfer in microchannels: a review of experimental results  

Microsoft Academic Search

A bibliographical review on the convective heat transfer through microchannels is presented. The available experimental works quoted in the open literature are critically analysed in order to highlight the main results obtained on the friction factor, on the laminar-to-turbulent transition and on the Nusselt number in channels having a hydraulic diameter less than 1 mm. A comparison of the experimental

Gian Luca Morini

2004-01-01

167

Measurement of uranium enrichment by gamma spectroscopy: result of an experimental design  

E-print Network

PAPER Measurement of uranium enrichment by gamma spectroscopy: result of an experimental design Gamma spectroscopy is commonly used in nuclear safeguards to measure uranium enrichment. An experimental design has been carried out for the measurement of uranium enrichment using this technique with different

168

China Energy Efficiency Round Robin Testing Results for Room  

E-print Network

LBNL-3502E China Energy Efficiency Round Robin Testing Results for Room Air Conditioners Nan Zhou Round Robin Testing Results and Analysis by China National Institute of Standardization..................................................................................................................... 1 I.1.1 China's Energy Constraint Problem and the Need to Improve the Energy Efficiency of Energy

169

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

170

David Alciatore ("Dr. Dave") ILLUSTRATED PRINCIPLES "Squirt Part II: experimental results"  

E-print Network

David Alciatore ("Dr. Dave") ILLUSTRATED PRINCIPLES "Squirt ­ Part II: experimental results" Note." Sunscreen on the arms is also recommended. The "robot" is Dave Gross, a top regional player with a very

Alciatore, David G.

171

Experimental results and first 22 Na source image reconstruction by1  

E-print Network

Xenon (LXe) in the scintillation mode is studied for Positron Emission14 Tomography (PET) of small In [2], only performances of a single LXe prototype module in terms of energy, time and15 spatial resolution capabilities were estimated. Since then, a new experimental set-up with two16 LXe modules

Paris-Sud XI, Université de

172

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

E-print Network

THEORY VERSUS EXPERIMENTAL RESULTS AND COMPARISONS FOR FIVE ORIFICE-COMPENSATED HYBRID BEARING CONFIGURATIONS A Thesis by NANCY MARIE FRANCHEIC Submitted to the Office of Graduate Studies of Texas ARM University in partial fulfillment... of the requirements for the degree of MASTER OF SCIENCE December 1992 Major Subject: Mechanical Engineering THEORY VERSUS EXPERIMENTAL RESULTS AND COMPARISONS FOR FIVE ORIFICE-COMPENSATED HYBRID BEARING CONFIGURATIONS A Thesis by NANCY MARIE FRANCIIEI...

Franchek, Nancy Marie

2012-06-07

173

A Computational Model for Predicting Experimental RNA and DNA Nearest-Neighbor Free Energy Rankings  

PubMed Central

Hydrogen-bonding, intra-strand base-stacking, and inter-strand base-stacking energies were calculated for RNA and DNA dimers at the MP2(full)/6-311G** level of theory. Standard A-form RNA and B-form DNA geometries from average fiber diffraction data were employed for all base monomer and dimer geometries, and all dimer binding energies were obtained via single-point calculations. The effects of water solvation were considered using the PCM model. The resulting dimer binding energies were used to calculate the 10 unique RNA and 10 unique DNA computational nearest-neighbor energies, and the ranking of these computational nearest neighbor energies are in excellent agreement with the ranking of the experimental nearest neighbor free energies. These results dispel the notion that average fiber diffraction geometries are insufficient for calculating RNA and DNA stacking energies. PMID:21619071

Johnson, Charles A.; Bloomingdale, Richard J.; Ponnusamy, Vikram E.; Tillinghast, Conor A.; Znosko, Brent M.; Lewis, Michael

2011-01-01

174

Experimental Results for Temporally Overlapping Pulses from Quantel EverGreen 200 Laser  

NASA Technical Reports Server (NTRS)

This report will detail the experimental results and observations obtained while investigating the feasibility of temporally overlapping the two laser pulses from a Quantel EverGreen 200 Laser. This laser was specifically designed for Particle Imaging Velocimetry (PIV) applications and operate by emitting two 532 nm laser pulses that are seperated by an adjustable finite time (typically on the order of ten to hundreds of microseconds). However, the use of this model laser has found recent application for Pressure Sensitive Paint (PSP) testing, especially for rotorcraft research. For this testing, it is desired to only use one laser pulse. While this is easily done by only firing one of the laser heads, more excitation energy could conceivably be had if both laser heads are fired with zero pulse separation. In addition, recently large field-of-view PIV measurements have become possible and need ever increasing laser power to illuminate the larger areas. For this work, two different methods of timing the laser are investigated using both a traditional power meter to monitor laser power as well as a fast photodiode to determine pulse separation. The results are presented here as well as some simple implications for PIV experiments using these methods.

Watkins, A. Neal

2013-01-01

175

Electromagnetic properties of 100Mo: Experimental results and theoretical description of quadrupole degrees of freedom  

NASA Astrophysics Data System (ADS)

The Coulomb excitation experiment to study electromagnetic properties of the heaviest stable Mo isotope, 100Mo, was performed using a 76 MeV 32S beam from the Warsaw cyclotron U-200P. Magnitudes and relative signs of 26 E1, E2, E3, and M1 matrix elements coupling nine low-lying states in 100Mo were determined using the least-squares code gosia. Diagonal matrix elements (related to the spectroscopic quadrupole moments) of the 21+, 22+, and 23+ states as well as the 41+ state were extracted. The resulting set of reduced E2 matrix elements was complete and precise enough to obtain, using the quadrupole sum rules approach, quadrupole deformation parameters of 100Mo in its two lowest 0+ states: ground and excited. The overall deformation of the 01+ and 02+ states in 100Mo is of similar magnitude, in both cases larger compared to what was found for the neighboring isotopes 96Mo and 98Mo. At the same time, the asymetry parameters obtained for both states strongly differ, indicating a triaxial shape of the 100Mo nucleus in the ground state and a prolate shape in the excited 0+ state. Low-energy quadrupole excitations of the 100Mo nucleus were studied in the frame of the general quadrupole collective Bohr Hamiltonian model (GBH). The potential energy and inertial functions were calculated using the adiabatic time-dependent Hartree-Fock-Bogoliubov (ATDHFB) method starting from two possible variants of the Skyrme effective interaction: SIII and Sly4. The overall quadrupole deformation parameters resulting from the GBH calculations with the SLy4 variant of the Skyrme interaction are slightly closer to the experimentally obtained values than those obtained using SIII.

Wrzosek-Lipska, K.; Próchniak, L.; Zieli?ska, M.; Srebrny, J.; Hady?ska-Kl?k, K.; Iwanicki, J.; Kisieli?ski, M.; Kowalczyk, M.; Napiorkowski, P. J.; Pi?tak, D.; Czosnyka, T.

2012-12-01

176

Hyperfine-structure studies of Zr ii: Experimental and relativistic configuration-interaction results  

NASA Astrophysics Data System (ADS)

We report an experimental and theoretical study of the hyperfine structure (hfs) in various metastable levels in 91Zr ii. Hyperfine structures in 11 levels arising from the 4d3 and 4d25s configurations were measured using the laser-rf double-resonance method in a collinear laser-ion-beam geometry. The hfs A and B constants were measured to a precision of 4 and 11 kHz, respectively. Less precise values for hfs constants for nine upper levels in the 4d25p configuration were derived from optical spectra. Theoretically, the A and B constants for the metastable levels having J=0.5 and 1.5 were calculated using a relativistic configuration-interaction (RCI) approach. The final many-body wave function produced energy gaps between the five J=0.5 levels which differ from experiment by an average of 0.050 eV, whereas the corresponding value for the ten J=1.5 levels is 0.087 eV. For the two J=0.5 levels measured and calculated, the average error in A is 31.8%. For the three J=1.5 levels, the situation is better, with the average error in A being 9.2%. For comparison, the average errors in A using independent-particle Dirac-Fock (DF) wave functions were 88% and 136% for J=0.5 and 1.5, respectively. In all cases, the many-body (RCI) result represents a vast improvement from the DF result for the A values. The value for the electric-quadrupole moment of 91Zr obtained from a comparison of the experimental B values and theoretical matrix elements is 0.257(0.013) b. In addition, the calculations confirm a previous report that the level at 17 614.00 cm-1 reported in Moore's Atomic Energy Levels, Vol. II (U.S. Government Printing Office, Washington, D.C., 1971) is spurious.

Young, L.; Kurtz, C. A.; Beck, Donald R.; Datta, Debasis

1993-07-01

177

Experimental energy straggling of protons in SiO{sub 2}  

SciTech Connect

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

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

2003-10-01

178

Experimental studies on coupling coefficient of impulse in materials irradiated by high-energy laser  

Microsoft Academic Search

The coupling coefficient of two kinds of materials (paint A and paint B) irradiated by pulsed high-energy laser was studied experimentally in this paper, and the sensor technique that using the principles of directly measuring the specific time intervals was introduced. Results showed that, under the radiation of high-energy laser, the coupling coefficient of impulse is 4.64xlO-SN-W-l for paint A,

Chang-Li Wang; Peng Lin; Hui Wang; Deng-Wang Wang

2011-01-01

179

RESEARCH RESULTS FORUM FOR RENEWABLE ENERGY TECHNOLOGY AND RESOURCE ASSESSMENTS  

E-print Network

impact on fatigue life? 17 #12;California Renewable Energy Center 18 Wind: Emerging Technologies;California Renewable Energy Center Organization of this session: · Overview of solar, wind, geothermal Angeles Basin results later (Task 2). #12;California Renewable Energy Center California Wind Energy

California at Davis, University of

180

RESEARCH RESULTS FORUM FOR RENEWABLE ENERGY TECHNOLOGY AND RESOURCE ASSESSMENTS  

E-print Network

Fowler (Ph.D. candidate) #12;California Renewable Energy Center 9:00 Introduction and Overview 9RESEARCH RESULTS FORUM FOR RENEWABLE ENERGY TECHNOLOGY AND RESOURCE ASSESSMENTS Public Workshop at the California Energy Commission (CEC) September 3, 2014 California Renewable Energy Center #12;California

California at Davis, University of

181

Experimental Results From Stitched Composite Multi-Bay Fuselage Panels Tested Under Uni-Axial Compression  

NASA Technical Reports Server (NTRS)

The experimental results from two stitched VARTM composite panels tested under uni-axial compression loading are presented. The curved panels are divided by frames and stringers into five or six bays with a column of three bays along the compressive loading direction. The frames are supported at the ends to resist out-of-plane translation. Back-to-back strain gages are used to record the strain and displacement transducers were used to record the out-of-plane displacements. In addition a full-field measurement technique that utilizes a camera-based-stero-vision system was used to record displacements. The panels were loaded in increments to determine the first bay to buckle. Loading was discontinued at limit load and the panels were removed from the test machine for impact testing. After impacting at 20 ft-lbs to 25 ft-lbs of energy with a spherical indenter, the panels were loaded in compression until failure. Impact testing reduced the axial stiffness 4 percent and less than 1 percent. Postbuckled axial panel stiffness was 52 percent and 70 percent of the pre-buckled stiffness.

Baker, Donald J.

2004-01-01

182

Development, calibration, and experimental results obtained with an innovative calorimeter (CALMOS) for nuclear heating measurements  

SciTech Connect

Nuclear heating inside an MTR reactor has to be known in order to be able to control samples temperature during irradiation experiments. An R and D program has been carried out at CEA to design a new type of in-core calorimetric system. This new development, started in 2002, has for main objective to manufacture a calorimeter suitable to monitoring nuclear heating inside the 70 MWth OSIRIS material testing reactor operated by CEA's Nuclear Energy Division at the Saclay research center. An innovative calorimetric probe, associated to a specific handling system, has been designed to provide access to measurements both along the fissile height and on the upper part of the core, where nuclear heating still remains high. Two mock-ups of the probe were manufactured and tested in 2005 and 2009 in ex-core area of OSIRIS reactor for process validation, while a displacement system has been especially studied to move the probe along a given axial measurement range. This paper deals with the development, tests on preliminary mock-ups and the finalization of the probe. Main modeling and experimental results are presented. Moreover, alternative methods to calibration for nuclear heating rate measurements which are now possible with this new calorimeter are presented and discussed. (authors)

Carcreff, Hubert; Cloute-Cazalaa, Veronique; Salmon, Laurent [CEA, DEN, DRSN, SIREN, LASPI Saclay, F-91191 Gif Sur Yvette, (France)

2012-08-15

183

Experimental Summary: Very High Energy Cosmic Rays and their Interactions  

NASA Astrophysics Data System (ADS)

The XVII International Symposium on Very High Energy Cosmic Ray Interactions, held in August of 2012 in Berlin, was the first one in the history of the Symposium,where a plethora of high precision LHC data with relevance for cosmic ray physics was presented. This report aims at giving a brief summary of those measurements andit discusses their relevance for observations of high energy cosmic rays. Enormous progress has been made also in air shower observations and in direct measurements of cosmic rays, exhibiting many more structure in the cosmic ray energy spectrum than just a simple power law with a knee and an ankle. At the highest energy, the flux suppression may not be dominated by the GZK-effect but by the limiting energy of a nearby source or source population. New projects and application of new technologies promise further advances also in the near future. We shall discuss the experimental and theoretical progress in the field and its prospects for coming years.

Kampert, Karl-Heinz

2013-06-01

184

Lifetime predictions for real loading situations—concepts and experimental results of fatigue crack growth  

Microsoft Academic Search

In this paper experimental results for real fatigue loading situations and loading changes are presented. It can be shown that the retardation effect depends on many factors, e.g. the overload ratio or the loading direction. Also, the lifetime is affected by the reconstruction of counting methods. In addition the results of simulations with the program code NASGRO are presented and

M. Sander; H. A. Richard

2003-01-01

185

Low Energy Experimental Elastic Cross Sections for Medical Physics Application  

NASA Astrophysics Data System (ADS)

Elastic cross sections for electron energies below 10 MeV are fundamental quantities needed in treatment planning systems used at hospitals and health facilities. To date, there is very little if not no data within that energy regime. In collaboration with the high current, high energy resolution continuous electron beam of the Department of Energy's Jefferson Lab accelerator, we have performed a first stage of dedicated experiments with energies of 100-150 keV to collect data for this type of reactions. The targets used were gold, copper and silver. A Mott scattering chamber was used to detect the outgoing electrons. We will present the first results of this program that aims at performing a wide range of measurements including the use of polarization data for spin studies.

Epps, Michael

2006-03-01

186

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.

187

Experimental Validation of Damping Model for a MEMS Bistable Electrostatic Energy Harvester  

NASA Astrophysics Data System (ADS)

This paper validates lumped models of an asymmetric bistable MEMS electrostatic energy harvester against measurements. A conventional model of constant damping coefficient turns out to be ineffective in predicting or reproducing the device response. This shortcoming is demonstrated by the effective damping coefficient obtained from fits to experimental results being far from constant under varying operating conditions. Therefore, two different nonlinear models of the damping force in polynomial form are introduced and investigated. We find that the experimental results are well reproduced over the entire range of measured acceleration amplitudes by modeling with a phenomenological nonlinear damping force which is a high-order polynomial in the velocity.

Nguyen, C. H.; Nguyen, D. S.; Halvorsen, E.

2014-11-01

188

Broadband permeability measurement method for ferrites at any magnetization state: Experimental results  

NASA Astrophysics Data System (ADS)

This paper describes the experimental results obtained by a broadband permeability measurement method based on the full-wave electromagnetic (EM) analysis of a non-reciprocal transmission line. The method offers a new experimental tool for measuring the broadband dynamic behavior of ferrites whatever their magnetization state. The methodology and experimental setup are presented with the aim of extracting both the permittivity and the two components (diagonal ? and off-diagonal ?) of the permeability tensor. Experimental data on commercial ferrites set in different magnetization states are presented and discussed. Furthermore, this method opens perspectives for the determination of other useful magnetic parameters such as resonance linewidth ?H. This quantity can be then measured at different frequencies, where conventional resonant methods give a value at a fixed frequency.

Chevalier, A.; Cortes, J.; Lezaca, J.; Queffelec, P.

2013-11-01

189

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

190

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

191

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

NASA Astrophysics Data System (ADS)

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

Coppersmith, Susan N.

2013-03-01

192

Armature reaction effects on a high temperature superconducting field winding of an synchronous machine: experimental results  

NASA Astrophysics Data System (ADS)

This paper presents experimental results from the Superwind laboratory setup. Particular focus in the paper has been placed on describing and quantifying the influence of armature reaction on performance of the HTS filed winding. Presented experimental results have confirmed the HTS field winding sensitivity to both armature reaction intensity and angular position with respect to the HTS coils. Furthermore, the characterization of the HTS field winding has been correlated to the electromagnetic torque of the machine where the maximal Ic reduction of 21% has been observed for the maximum torque.

Mijatovic, Nenad; Jensen, Bogi Bech

2014-05-01

193

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

194

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

PubMed

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

Ferrari, José A; Frins, Erna

2011-07-01

195

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

SciTech Connect

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

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

2011-07-15

196

Parametric Evaluation of Absorption Losses and Comparison of Numerical Results to Boeing 707 Aircraft Experimental HIRF Results  

NASA Astrophysics Data System (ADS)

A broadband (100 MHz-1.2 GHz) plane wave electric field source was used to evaluate electric field penetration inside a simplified Boeing 707 aircraft model with a finite-difference time-domain (FDTD) method using EMA3D. The role of absorption losses inside the simplified aircraft was investigated. It was found that, in this frequency range, none of the cavities inside the Boeing 707 model are truly reverberant when frequency stirring is applied, and a purely statistical electromagnetics approach cannot be used to predict or analyze the field penetration or shielding effectiveness (SE). Thus it was our goal to attempt to understand the nature of losses in such a quasi-statistical environment by adding various numbers of absorbing objects inside the simplified aircraft and evaluating the SE, decay-time constant ?, and quality factor Q. We then compare our numerical results with experimental results obtained by D. Mark Johnson et al. on a decommissioned Boeing 707 aircraft.

Kitaygorsky, J.; Amburgey, C.; Elliott, J. R.; Fisher, R.; Perala, R. A.

197

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

198

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

199

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

E-print Network

pressure sensor and three velocity-meters that are sensitive in a specific direction - x, y or z. SinceGeometric 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.

200

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

E-print Network

Dynamics of Dual Prism Adaptation: Relating Novel Experimental Results to a Minimalistic Neural direct effect, i.e. adaptation to prisms, and aftereffect, i.e. behavior after removal of prisms transfer and generalization of prism adaptation, as observed in other experiments. Citation: Are´valo O

Kreiter, Andreas K.

201

Studies of crack dynamics in clay soil I. Experimental methods, results, and morphological quantification  

E-print Network

Studies of crack dynamics in clay soil I. Experimental methods, results, and morphological geometric measures which provide a quantitative description of crack patterns at the soil surface including Minkowski functions. Additionally, we measured the distribution of angles within the crack network

Hoffmann, Heiko

202

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

203

Design of an automatic impedance matching system for industrial continuous microwave ovens. Part II: experimental results  

Microsoft Academic Search

The algorithm proposed in part I (see ibid., p.791-5) was carried out in an experimental test. This test is elaborated in order to make a fine tuning of the algorithm parameters and analyze the results. An artificial load was used, composed of a matched load with a mismatched device. The mismatch was obtained by varying the length of four screws

V. C. Parro; F. M. Pait

2003-01-01

204

Nodal and Mesh Analysis: Comparison of Analysis, Experimental, and Simulated (SPICE) Results  

E-print Network

1 Nodal and Mesh Analysis: Comparison of Analysis, Experimental, and Simulated (SPICE) Results ECE #12;2 Procedures Part One 1. Use your SPICE simulation engine to build an example circuit provided using your SPICE engine for your computed voltage VS and measured resistor values using a DC operating

Miller, Damon A.

205

Experimental results of ultrasonic monitoring of cryotherapy on in vitro skin samples of domestic pig  

Microsoft Academic Search

One of the principal difficulties encountered in cryosurgery is to know the extent and depth of the frozen tissue boundary during the freezing process and the extent of the cryonecrosis in the postfreezing period. The authors seek to evaluate echography possibilities in monitoring the freezing process during cryotherapy in dermatology. The first experimental results of ultrasound monitoring of the freezing

P. Laugier; G. Berger

1992-01-01

206

Probing a cold surface with slow heavy-atom scattering: Experimental results and theoretical calculations  

E-print Network

Probing a cold surface with slow heavy-atom scattering: Experimental results and theoretical manuscript received 20 September 2001; published 2 January 2002 Slow heavy atoms scattering from cold, which is slow and strong, it is typically much more complex.2 In the common case of a light particle

Burke, Kieron

207

Simulation and experimental results of kaleidoscope homogenizers for longitudinal diode pumping.  

PubMed

With the goal to set a homogenizer to allow coupling of a stack of diodes with a disk amplifier medium for a longitudinally pumped laser or amplifier, we report simulation and experimental results on homogenization of the light supplied by a large stack of diodes. We investigate various kaleidoscope cross-section shapes and various optical coupling configurations. PMID:20300161

Bartnicki, Eric; Bourdet, Gilbert L

2010-03-20

208

Correlation of fretting fatigue experimental results using an asymptotic approach D.A. Hills a  

E-print Network

Correlation of fretting fatigue experimental results using an asymptotic approach D.A. Hills a , A online 23 February 2012 Keywords: Fretting fatigue Incomplete contacts Asymptotic methods Short crack. They are then used to re-analyse several sets of publicly available fretting fatigue data. Several different

Barber, James R.

209

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

E-print Network

Modeling and Identification of 2 DOF Low Cost Driving Simulator: Experimental Results Hichem Arioui and the modeling aspects of a 2 DOF low cost motion platform allowing the restitution of the longitudinal and yaw. For this reason, it was interesting to offer targeted solutions based low-cost mobile platforms aimed primarily

Paris-Sud XI, Université de

210

Electron Impact H-H and D-D Fusions in Molecules Embedded in Al I. Experimental Results  

NASA Astrophysics Data System (ADS)

Both H-H and D-D fusion reactions, detected via high energy particle emission on CR-39, are shown to occur when 200 and 400 keV electrons are bombarded onto H+ or D+ ion implanted Al thin crystals. Roughly 1--2× 103 particle emissions, including both hydrogen and helium isotopes, in whole space were observed in each case. Collisions between recoilled D atoms due to the high energy electron impact give only 10-12 to 10-26 times smaller fusion rates than the experimental results. The present observations suggest the presence of a new kind of fusion reaction which occurs with negligible kinetic energy of the reacting nuclei.

Kamada, Kohji

1992-09-01

211

Broadband optical cavities for infrared free electron lasers: analysis and preliminary experimental results  

SciTech Connect

In this work we describe the complete design of a broadband optical cavity for a new IR free electron laser under construction at Stanford using the first section of the Mark III linac. Although the numerical results apply specifically to the Mark III FEL, the general scheme is applicable to any tunable free electron laser. In the last section, some preliminary experimental results for the acoustooptic output coupler are reported and discussed.

Cutolo, A.; Khuri-Yakub, B.T.; Madey, J.M.J.

1984-09-01

212

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

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

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

215

Evaluating impacts of CO2 gas intrusion into a confined sandstone aquifer: Experimental results  

SciTech Connect

Deep subsurface storage and sequestration of CO2 has been identified as a potential mitigation technique for rising atmospheric CO2 concentrations. Sequestered CO2 represents a potential risk to overlying aquifers if the CO2 leaks from the deep storage reservoir. Experimental and modeling work is required to evaluate potential risks to groundwater quality and develop a systematic understanding of how CO2 leakage may cause important changes in aquifer chemistry and mineralogy by promoting dissolution/precipitation, adsorption/desorption, and redox reactions. Sediments from the High Plains aquifer in Kansas, United States, were used in this investigation, which is part of the National Risk Assessment Partnership Program sponsored by the US Department of Energy. This aquifer was selected to be representative of consolidated sand and gravel/sandstone aquifers overlying potential CO2 sequestration repositories within the continental US. In this paper, we present results from batch experiments conducted at room temperature and atmospheric pressure with four High Plains aquifer sediments. Batch experiments simulate sudden, fast, and short-lived releases of the CO2 gas as would occur in the case of well failure during injection. Time-dependent release of major, minor, and trace elements were determined by analyzing the contacting solutions. Characterization studies demonstrated that the High Plains aquifer sediments were abundant in quartz and feldspars, and contained about 15 to 20 wt% montmorillonite and up to 5 wt% micas. Some of the High Plains aquifer sediments contained no calcite, while others had up to about 7 wt% calcite. The strong acid extraction tests confirmed that in addition to the usual elements present in most soils, rocks, and sediments, the High Plains aquifer sediments had appreciable amounts of As, Cd, Pb, Cu, and occasionally Zn, which potentially may be mobilized from the solid to the aqueous phase during or after exposure to CO2. However, the results from the batch experiments showed that the High Plains sediments mobilized only low concentrations of trace elements (potential contaminants), which were detected occasionally in the aqueous phase during these experiments. Importantly, these occurrences were more frequent in the calcite-free sediment. Results from these investigations provide useful information to support site selection, risk assessment, and public education efforts associated with geological CO2 storage and sequestration.

Qafoku, Nikolla; Lawter, Amanda R.; Shao, Hongbo; Wang, Guohui; Brown, Christopher F.

2014-12-31

216

Application of an Unstructured Grid Navier-Stokes Solver to a Generic Helicopter Boby: Comparison of Unstructured Grid Results with Structured Grid Results and Experimental Results  

NASA Technical Reports Server (NTRS)

An unstructured-grid Navier-Stokes solver was used to predict the surface pressure distribution, the off-body flow field, the surface flow pattern, and integrated lift and drag coefficients on the ROBIN configuration (a generic helicopter) without a rotor at four angles of attack. The results are compared to those predicted by two structured- grid Navier-Stokes solvers and to experimental surface pressure distributions. The surface pressure distributions from the unstructured-grid Navier-Stokes solver are in good agreement with the results from the structured-grid Navier-Stokes solvers. Agreement with the experimental pressure coefficients is good over the forward portion of the body. However, agreement is poor on the lower portion of the mid-section of the body. Comparison of the predicted surface flow patterns showed similar regions of separated flow. Predicted lift and drag coefficients were in fair agreement with each other.

Mineck, Raymond E.

1999-01-01

217

Experimental and Theoretical Analysis of Low-energy CO + H2 Inelastic Collisions  

NASA Astrophysics Data System (ADS)

Carbon monoxide is one of the most abundant components in many interstellar media and modeling its spectra requires knowledge of rate coefficients for the rotational (de-)excitation by collision with the dominant species in molecular regions, H2. In this Letter, we report on experimental observation of resonances in the collisional excitation of CO by para- and ortho-H2 at low collision energies characteristic of cold molecular clouds (down to a few Kelvin). Our experimental integral cross sections are compared to the results of new quantum mechanical scattering calculations performed using the highly accurate ab initio potential energy surface of Jankowski et al. Since the scattering calculations are very sensitive to the accuracy of the potential, especially when quantum resonances are involved, the quality of the agreement between theory and experiment reinforces the confidence in the observables derived from this potential energy surface, such as collisional rate coefficients calculated in the 1-20 K range.

Chefdeville, S.; Stoecklin, T.; Naulin, C.; Jankowski, P.; Szalewicz, K.; Faure, A.; Costes, M.; Bergeat, A.

2015-01-01

218

Axisymmetric laser welding of ceramics: comparison of experimental and finite element results  

NASA Astrophysics Data System (ADS)

In this paper, we compare experimental data for a laser spot weld on a ceramic to the solution from an adaptive finite element model of the system. Our focus is on validating the finite element model, which necessarily includes numerous simplifications. We assume an axisymmetric geometry and flow profile, with a flat free surface. Buoyancy and surface tension drive the liquid motion in the molten ceramic pool beneath the laser, which is calculated using the axisymmetric forms of the continuity, momentum and energy equations. Latent heat, temperature-dependent material properties and radiation effects are all included in the formulation. These equations are solved with standard finite element techniques utilizing mesh relocation with a movement indicator based on solution gradients. Comparision with experimental data indicates that the numerical techniques used successfully predicted the depth and diameter of the actual ceramic weld pool.

Hirsch, J. W.; Olson, L. G.; Nazir, Z.; Alexander, D. R.

1998-06-01

219

Experimental evaluation of exhaust mixers for an Energy Efficient Engine  

NASA Technical Reports Server (NTRS)

Static scale model tests were conducted to evaluate exhaust system mixers for a high bypass ratio engine as part of the NASA sponsored Energy Efficient program. Gross thrust coefficients were measured for a series of mixer configurations which included variations in the number of mixer lobes, tailpipe length, mixer penetration, and length. All of these parameters have a significant impact on exhaust system performance. In addition, flow visualization pictures and pressure/temperature traverses were obtained for selected configurations. Parametric performance trends are discussed and the results considered relative to the Energy Efficient Engine program goals.

Kozlowski, H.; Kraft, G.

1980-01-01

220

Experimental limit on the cosmic diffuse ultrahigh energy neutrino flux.  

PubMed

We report results from 120 h of live time with the Goldstone lunar ultrahigh energy neutrino experiment (GLUE). The experiment searches for < or = 10 ns microwave pulses from the lunar regolith, appearing in coincidence at two large radio telescopes separated by 22 km and linked by optical fiber. Such pulses would arise from subsurface electromagnetic cascades induced by interactions of > or = 100 EeV (1 EeV = 10(18) eV neutrinos in the lunar regolith. No candidates are yet seen, and the implied limits constrain several current models for ultrahigh energy neutrino fluxes. PMID:15323748

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

2004-07-23

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

Review on optical constants of Titan aerosols: Experimental results and modeling/observational data  

NASA Astrophysics Data System (ADS)

During the last years many studies have been performed to improve the experimental database of optical constants of Titan aerosols. Indeed, the determination of the optical constants of these particles is essential to quantify their capacity to absorb and to scatter solar radiation, and thus to evaluate their role on Titan's radiative balance and climate. The study of optical properties is also crucial to analyze and to better interpret many of Titan's observational data, in particular those acquired during the Cassini-Huygens mission. One way to determine Titan aerosols optical constant is to measure the optical constants of analogues of Titan complex organic material synthesized in the laboratory, usually named Titan's tholins (Sagan and Khare, 1979). But the optical constants depend on the chemical composition, the size and the shape of particles (Raulin et al., 2012). Those three parameters result from the experimental conditions such as energy source, gas mixing ratio, gas pressure, flow rate and irradiation time (Cable et al., 2012). Besides the determination of the refractive index in the laboratory, there are others methods using theoretical models or observational data. Nevertheless, theoretical models are based on laboratory data or/and observational data. The visible - near infrared spectral region of optical constants has been widely studied with laboratory analogues. Comparison of the obtained results suggest that tholins synthesized by Tran et al. (2003) and Majhoub et al. (2012) are the best representative of Titan aerosols with regards to their refractive indexes in this spectral region. The mid-infrared spectral range has been studied only by Imanaka et al. (2012) and slightly by Tran et al. (2003). In that spectral range, Titan tholins do not exhibit the features displayed by Kim and Courtin (2013) from Titan's observations. For spectral region of wavelengths smaller than 0.20µm or higher than 25µm, only the data from Khare et al. (1984) are available. Therefore it would be very useful to get more laboratory data and especially from Tran et al (2013), Mahjoub et al. (2012) and Imanaka et al. (2012) samples in these spectral regions since their refractive indexes match observational and theoretical data in other spectral ranges. This presentation will critically summarize these recent results and present detailled constraints on the optical constants Titan's aerosols. In addition, specific lacks of data will be highlighted as well as some possible investigations to be carried out to fill these gaps. References: Cable, M. L., et al., 2012. Titan Tholins: Simulating Titan Organic Chemistry in the Cassini-Huygens Era. Chemical Reviews. 112, 1882-1909. Imanaka, H., et al., 2012. Optical constants of Titan tholins at mid-infrared wavelengths (2.5-25 µm) and the possible chemical nature of Titan's haze particles. Icarus. 218, 247-261. Khare, B. N., et al., 1984. Optical-Constants of Organic Tholins Produced in a Simulated Titanian Atmosphere - from Soft-X-Ray to Microwave-Frequencies. Icarus. 60, 127-137. Kim, S. J., Courtin, R., 2013. Spectral characteristics of the Titanian haze at 1-5 micron from Cassini/VIMS solar occultation data. Astronomy & Astrophysics. 557, L6. Mahjoub, A., et al., 2012. Influence of methane concentration on the optical indices of Titan's aerosols analogues. Icarus. 221, 670-677. Raulin, F., et al., 2012. Prebiotic-like chemistry on Titan. Chemical Society Reviews. 41, 5380-5393. Sagan, C., Khare, B. N., 1979. Tholins - Organic-Chemistry of Inter-Stellar Grains and Gas. Nature. 277, 102-107. Tran, B. N., et al., 2003. Simulation of Titan haze formation using a photochemical flow reactor - The optical constants of the polymer. Icarus. 165, 379-390. Acknowledgements: We acknowledge support from the French Space Agency (CNES) and the European Space Agency (ESA).

Brassé, Coralie; Muñoz, Olga; Coll, Patrice; Raulin, François

2014-05-01

223

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

224

Predictions of the equation of state of cerium yield interesting insights into experimental results  

SciTech Connect

There has been much interest in the past in understanding the dynamic properties of phase changing materials. In this paper we begin to explore the dynamic properties of the complex material of cerium. Cerium metal is a good candidate material to explore capabilities in determining a dynamic phase diagram on account of its low dynamic phase boundaries, namely, the {gamma}-{alpha}, and {alpha}-liquid phase boundaries. Here we present a combination of experimental results with calculated results to try to understand the dynamic behavior of the material. Using the front surface impact technique, we performed a series of experiments which displayed a rarefaction shock upon release. These experiments show that the reversion shock stresses occur at different magnitudes, allowing us to plot out the {gamma}-{alpha} phase boundary. Applying a multiphase equation of state a broader understanding of the experimental results will be discussed.

Cherne, Frank J [Los Alamos National Laboratory; Jensen, Brian J [Los Alamos National Laboratory; Rigg, Paulo A [Los Alamos National Laboratory; Elkin, Vyacheslav M [VNIITF

2009-01-01

225

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

NASA Astrophysics Data System (ADS)

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

Goldhirsh, Julius; Vogel, Wolfhard J.

1992-02-01

226

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

227

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

228

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

NASA Astrophysics Data System (ADS)

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 LXe 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 an LXe PET configuration might be a promising solution insensitive to any parallax effect.

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

2009-02-01

229

Experimental Analysis of a Coupled Energy Harvesting System with Monostable and Bistable Configuration  

NASA Astrophysics Data System (ADS)

In this paper we present experimental results from an energy harvesting system with two coupled energy harvesters. The energy conversion mechanism of the two coupled energy harvesters is based on the electromagnetic principle. The coupling is generated by two magnets in a repulsive arrangement. In this manner a bistable configuration can be obtained if the gap between the magnets is sufficiently small. We demonstrate that the total power output can be increased in comparison to a linear reference system, if specific conditions are fulfilled. In this respect, the highest power output occurs in the nonlinear region of a monostable system configuration, mostly near the transition to a bistable configuration. On the other hand, the results also indicate, that a bistable operating mode does not necessarily enhance the power output of the coupled system.

Hoffmann, D.; Folkmer, B.; Manoli, Y.

2014-11-01

230

Experimental and Analytical Evaluation of a Composite Honeycomb Deployable Energy Absorber  

NASA Technical Reports Server (NTRS)

In 2006, the NASA Subsonic Rotary Wing Aeronautics Program sponsored the experimental and analytical evaluation of an externally deployable composite honeycomb structure that is designed to attenuate impact energy during helicopter crashes. The concept, which is designated the Deployable Energy Absorber (DEA), utilizes an expandable Kevlar honeycomb structure to dissipate kinetic energy through crushing. The DEA incorporates a unique flexible hinge design that allows the honeycomb to be packaged and stowed flat until needed for deployment. A variety of deployment options such as linear, radial, and/or hybrid methods can be used. Experimental evaluation of the DEA utilized a building block approach that included material characterization testing of its constituent, Kevlar -129 fabric/epoxy, and flexural testing of single hexagonal cells. In addition, the energy attenuation capabilities of the DEA were demonstrated through multi-cell component dynamic crush tests, and vertical drop tests of a composite fuselage section, retrofitted with DEA blocks, onto concrete, water, and soft soil. During each stage of the DEA evaluation process, finite element models of the test articles were developed and simulations were performed using the explicit, nonlinear transient dynamic finite element code, LS-DYNA. This report documents the results of the experimental evaluation that was conducted to assess the energy absorption capabilities of the DEA.

Jackson, Karen E.; Kellas, Sotiris; Horta, Lucas G.; Annett, Martin S.; Polanco, Michael A.; Littell, Justin D.; Fasanella, Edwin L.

2011-01-01

231

Numerical predictions and experimental results of a dry bay fire environment.  

SciTech Connect

The primary objective of the Safety and Survivability of Aircraft Initiative is to improve the safety and survivability of systems by using validated computational models to predict the hazard posed by a fire. To meet this need, computational model predictions and experimental data have been obtained to provide insight into the thermal environment inside an aircraft dry bay. The calculations were performed using the Vulcan fire code, and the experiments were completed using a specially designed full-scale fixture. The focus of this report is to present comparisons of the Vulcan results with experimental data for a selected test scenario and to assess the capability of the Vulcan fire field model to accurately predict dry bay fire scenarios. Also included is an assessment of the sensitivity of the fire model predictions to boundary condition distribution and grid resolution. To facilitate the comparison with experimental results, a brief description of the dry bay fire test fixture and a detailed specification of the geometry and boundary conditions are included. Overall, the Vulcan fire field model has shown the capability to predict the thermal hazard posed by a sustained pool fire within a dry bay compartment of an aircraft; although, more extensive experimental data and rigorous comparison are required for model validation.

Suo-Anttila, Jill Marie; Gill, Walter; Black, Amalia Rebecca

2003-11-01

232

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

233

16th intersociety energy conversion engineering conference. CDIF - activation completion and initial MHD test results  

Microsoft Academic Search

The Component Development and Integration Facility (CDIF) is one of the Department of Energy's (DOE) Magnetohydrodynamics (MHD) experimental test facilities. The scope of this paper is limited to a brief description of the facility activation and results from the initial MHD testing using an oil fired ash injected combustor (AIC) and a supersonic channel. 1 ref.

G. E. Staats; V. J. DeJong; R. J. Karvinen; R. A. Carrington; L. E. Bauman

1981-01-01

234

Experimental evaluation of a stationary spherical reflector tracking absorber solar energy collector  

NASA Technical Reports Server (NTRS)

This article presents experimental data for the thermal performance of a stationary, spherical-reflector, tracking-absorber solar energy collector (SRTA). The principle of operation and details of thermal performance of such an SRTA have previously been described. These experimental results were compared with the predictions of a thermal analysis previously published. Experimental results were compared with the prediction of Kreider's computer model. Within the range of the temperature of the experiments, the predicted performance of the unit agreed well with experimental data collected under clear sky conditions. In addition, the extrapolation of the efficiency to higher temperature is shown so that the potential of an SRTA solar collector as a means of providing high temperature steam to operate an electric power facility or for process heat can be evaluated. As a result of the tests conducted by NASA, and an economic analysis not yet publicly available, it appears that the SRTA solar collector concept will be economically viable in competition with any other existing solar system in providing electrical energy.

Steward, W. G.; Kreider, J. F.; Caruso, P. S., Jr.; Kreith, F.

1976-01-01

235

Experimental High Energy Physics Research: Direct Detection of Dark Matter  

SciTech Connect

The grant supported research on an experimental search for evidence of dark matter interactions with normal matter. The PI carried out the research as a member of the LUX and LZ collaborations. The LUX research team collected a first data set with the LUX experiment, a large liquid xenon detector installed in the Sanford Underground Research Facility (SURF). The first results were published in Physical Review Letters on March 4, 2014. The journal Nature named the LUX result a scientific highlight of the year for 2013. In addition, the LZ collaboration submitted the full proposal for the Lux Zeplin experiment, which has since been approved by DOE-HEP as a second-generation dark matter experiment. Witherell is the Level 2 manager for the Outer Detector System on the LUX-Zeplin experiment.

Witherell, Michael S.

2014-10-02

236

Controls-structures interaction guest investigator program: Overview and phase 1 experimental results and future plans  

NASA Technical Reports Server (NTRS)

The NASA Controls-Structures Interaction (CSI) Guest Investigator program is described in terms of its support of the development of CSI technologies. The program is based on the introduction of CSI researchers from industry and academia to available test facilities for experimental validation of technologies and methods. Phase 1 experimental results are reviewed with attention given to their use of the Mini-MAST test facility and the facility for the Advance Control Evaluation of Structures. Experiments were conducted regarding the following topics: collocated/noncollocated controllers, nonlinear math modeling, controller design, passive/active suspension systems design, and system identification and fault isolation. The results demonstrate that significantly enhanced performance from the control techniques can be achieved by integrating knowledge of the structural dynamics under consideration into the approaches.

Smith-Taylor, Rudeen; Tanner, Sharon E.

1993-01-01

237

A study on the failure of circular plates struck by masses. Part 1: experimental results  

Microsoft Academic Search

In the present study experimental results recorded from a series of tests are presented, which examine the dynamic response and petalling failure of thin circular plates struck transversely at the centre by masses having conical heads and spherical noses. The circular plates are cut from mild steel plates with five different thicknesses of 1.17, 1.5, 2, 3 and 4mm and

W. Q. Shen; N. O. Rieve; B. Baharun

2002-01-01

238

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

SciTech Connect

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

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

2008-06-23

239

STRAIN-BALANCED MULTI QUANTUM WELL SOLAR CELLS IN TANDEM STRUCTURES - FIRST EXPERIMENTAL RESULTS  

Microsoft Academic Search

The first results are presented of a monolithic, two terminal tandem solar cell incorporating strain- balanced multi-quantum-wells (MQW) into the second, GaAs based junction. This approach is expected to boost the photocurrent of the lower junction, allowing better spectral matching between top and bottom junctions without the need to thin the top cell. Measured efficiencies of experimental devices compare well

T. N. D. Tibbits; I. M. Ballard; K. W. J. Barnham; D. B. Bushnell; J. P. Connolly; G. Hill; J. S. Roberts; R. Airey; G. Smekens

240

Experimental Results on the Missing Cone Problem in Computer Aided Tomography  

PubMed Central

This experimental paper discusses some results on the missing cone problem in computer aided tomography. Several methods are discussd for 1-dimensional signal reconstruction and their extension to the 2-d case. Here we propose the iterative Gerchberg algorithm for reconstructing the missing cone of the CAT scan in the Fourier domain. Further the performance of the reconstruction algorithm is investigated when the projection information from the CAT scanner is corrupted with noise. ImagesFigure 6AFigure 6BFigure 6C

Renjen, Sanjeev; Huang, Tom S.

1981-01-01

241

Estimating the hyperfine coupling parameters of the avian compass by comprehensively considering the available experimental results.  

PubMed

Migratory birds can utilize the geomagnetic field for orientation and navigation through a widely accepted radical-pair mechanism. Although many theoretical works have been done, the available experimental results have not been fully considered, especially the temporary disorientation induced by the field which is increased by 30% of the geomagnetic field and the disorientation of the very weak resonant field of 15 nT. In this paper, we consider the monotonicity of the singlet yield angular profile as the prerequisite of direction sensitivity, and find that for some optimal values of the hyperfine coupling parameters (that is, the order of 10^{-7}?10^{-6} meV) the experimental results available so far can be satisfied. We also investigate the effects of two decoherence environments and demonstrate that, in order to satisfy the available experimental results, the decoherence rate should be lower than the recombination rate. Finally, we investigate the effects of the fluctuating magnetic noises and find that the vertical noise destroys the monotonicity of the profile completely, but the parallel noise preserves the monotonicity perfectly and even can enhance the direction sensitivity. PMID:24125290

Xu, Bao-Ming; Zou, Jian; Li, Jun-Gang; Shao, Bin

2013-09-01

242

Energy Results of ISO 50001 Deployment by Program Administrators  

E-print Network

results, and since its release in 2011 numerous companies around the world have deployed it. At the same time, program administrators from leading utilities and resource acquisition organizations have implemented energy efficiency programs that target...

Brown, K.; Gilless, C.; Milward, R.

2013-01-01

243

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 µm (? =1 g?cm–3). 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. PMID:25333022

2014-01-01

244

Studies of Multipactor in Dielectric-Loaded Accelerator Structures: Comparison of Simulation Results with Experimental Data  

SciTech Connect

In this paper new results of numerical studies of multipactor in dielectric-loaded accelerator structures are presented. The results are compared with experimental data obtained during recent studies of such structures performed by Argonne National Laboratory, the Naval Research Laboratory, SLAC National Accelerator Laboratory and Euclid TechLabs, LLC. Good agreement between the theory and experiment was observed for the structures with larger inner diameter, however the structures with smaller inner diameter demonstrated a discrepancy between the two. Possible reasons for such discrepancy are discussed.

Sinitsyn, Oleksandr; Nusinovich, Gregory; Antonsen, Thomas Jr. [Institute for Research in Electronics and Applied Physics, University of Maryland, College Park, MD 20742-3511 (United States)

2010-11-04

245

Electron emission from surfaces resulting from low energy positron bombardment  

NASA Astrophysics Data System (ADS)

Measurements of the energy distribution of electrons resulting from very low energy positron bombardment of a polycrystalline Au and Cu(100) surfaces provide evidence for a single step transition from an unbound scattering state to an image potential bound state. The primary positron energy threshold for secondary electron emission and cutoff in the secondary electron energy spectra are consistent with a process in which an incident positrons make a transition from a scattering state to a surface-image potential bound while transferring all of the energy difference to an outgoing secondary electron. Estimates of the probability of this process as a function of incident positron energy are also presented. Background free Auger spectra of the MVV transition in Cu and the OVV transition in Au were obtained by setting the incident positron beam energy below the secondary electron emission threshold. Auger electron emission resulted from the annihilation of surface state positrons with core electrons. The low energy tail associated with the low energy CVV Auger transitions in Cu and Au were found to have integrated intensity several times larger than Auger peak providing strong evidence for multi-electron Auger processes.

Mukherjee, S.; Shastry, K.; Weiss, A. H.

2009-03-01

246

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

SciTech Connect

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

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

2001-08-01

247

Vibration Based Crack Detection in a Rotating Disk. Part 2; Experimental Results  

NASA Technical Reports Server (NTRS)

This paper describes the experimental results concerning the detection of a crack in a rotating disk. The goal was to utilize blade tip clearance and shaft vibration measurements to monitor changes in the system's center of mass and/or blade deformation behaviors. The concept of the approach is based on the fact that the development of a disk crack results in a distorted strain field within the component. As a result, a minute deformation in the disk's geometry as well as a change in the system's center of mass occurs. Here, a notch was used to simulate an actual crack. The vibration based experimental results failed to identify the existence of a notch when utilizing the approach described above, even with a rather large, circumferential notch (l.2 in.) located approximately mid-span on the disk (disk radius = 4.63 in. with notch at r = 2.12 in.). This was somewhat expected, since the finite element based results in Part 1 of this study predicted changes in blade tip clearance as well as center of mass shifts due to a notch to be less than 0.001 in. Therefore, the small changes incurred by the notch could not be differentiated from the mechanical and electrical noise of the rotor system. Although the crack detection technique of interest failed to identify the existence ofthe notch, the vibration data produced and captured here will be utilized in upcoming studies that will focus on different data mining techniques concerning damage detection in a disk.

Gyekenyesi, Andrew L.; Sawicki, Jerzy T.; Martin, Richard E.; Haase, Wayne C.; Baaklini, George

2005-01-01

248

Electron emission from surfaces resulting from low energy positron bombardment  

NASA Astrophysics Data System (ADS)

Measurements of the secondary electron energy spectra resulting from very low energy positron bombardment of a polycrystalline Au and Cu (100) surfaces are presented that provide evidence for a single step transition from an unbound scattering state to an image potential bound state. The primary positron energy threshold for secondary electron emission and energy cutoff of the positron induced secondary electron energy peak are consistent with an Auger like process in which an incident positron make a transition from a scattering state to a surface-image potential bound while transferring all of the energy difference to an outgoing secondary electron. We term this process: the Auger mediated quantum sticking effect (AQSE). The intensities of the positron induced secondary electron peak are used to estimate the probability of this process as a function of incident positron energy. Positron annihilation induced Auger spectra (PAES) of Cu and Au are presented that are free of all primary beam induced secondary electron background. This background was eliminated by setting the positron beam energy below AQSE threshold. The background free PAES spectra obtained include the first measurements of the low energy tail of CVV Auger transitions all the way down to zero kinetic energy. The integrated intensity of this tail is several times larger than Auger peak itself which provides strong evidence for multi-electron Auger processes.

Mukherjee, Saurabh

249

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 1.3 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. 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; García-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-López, 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; Tomás, 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

250

Experimental results from the HDL orotron - A tunable source of coherent millimeter wave radiation  

NASA Astrophysics Data System (ADS)

The present investigation is concerned with recent experimental results obtained from the Harry Diamond Laboratories (HDL) orotron, a free electron laser (FEL). A description is provided of experimental observations of orotron oscillations. In the HDL orotron a 0.3 mm x 10.0 mm electron beam passes over and interacts with a copper reflecting diffraction grating. This grating is imbedded in a cylindrical mirror which, with a spherical mirror above it, forms an open resonator that allows good mode selection. This resonator reflects the radiation emitted by the beam back onto the beam and causes beam bunching. Attention is also given to a novel technique for obtaining hundred nanosecond pulses by the use of 10 V modulation signals.

Dropkin, H.; Leavitt, R. P.; Wortman, D. E.

251

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

252

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

253

Use of dynamic theory to describe experimental results from volume holography  

NASA Technical Reports Server (NTRS)

The general applicability of dynamic theory to the description of the recording and readout characteristics of volume (thick) hologram gratings is indicated. In dynamic theory (as opposed to static theory), the volume nature of the thick holographic grating allows the interference of an incident light beam with its own diffracted beam inside the recording medium. This effect causes the continuous recording of another grating that alters the initial one, producing a resultant grating that is not uniform through the thickness of the recording material and a grating whose writing and reading characteristics may vary dramatically, depending on the recording material and the experimental conditions. A large number of diverse types of writing, reading, and angular-selectivity behavior have been reported. The dynamic theory of thick-hologram writing and reading is shown to predict qualitatively all of these various types of experimental behavior.

Magnusson, R.; Gaylord, T. K.

1976-01-01

254

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

255

LBE water interaction in sub-critical reactors: First experimental and modelling results  

NASA Astrophysics Data System (ADS)

This paper concerns the study of the phenomena involved in the interaction between LBE and pressurised water which could occur in some hypothetical accidents in accelerator driven system type reactors. The LIFUS 5 facility was designed and built at ENEA-Brasimone to reproduce this kind of interaction in a wide range of conditions. The first test of the experimental program was carried out injecting water at 70 bar and 235 °C in a reaction vessel containing LBE at 1 bar and 350 °C. A pressurisation up to 80 bar was observed in the test section during the considered transient. The SIMMER III code was used to simulate the performed test. The calculated data agree in a satisfactory way with the experimental results giving confidence in the possibility to use this code for safety analyses of heavy liquid metal cooled reactors.

Ciampichetti, A.; Agostini, P.; Benamati, G.; Bandini, G.; Pellini, D.; Forgione, N.; Oriolo, F.; Ambrosini, W.

2008-06-01

256

Experimental energy resolution of a paracentric hemispherical deflector analyzer for different entry positions and bias  

NASA Astrophysics Data System (ADS)

A specially designed hemispherical deflector analyzer (HDA) with 5-element input lens having a movable entry position R0 suitable for electron energy analysis in atomic collisions was constructed and tested. The energy resolution of the HDA was experimentally determined for three different entry positions R0 = 84, 100, 112 mm as a function of the nominal entry potential V(R0) under pre-retardation conditions. The resolution for the (conventional) entry at the mean radius R0 = 100 mm was found to be a factor of 1.6-2 times worse than the resolution for the two (paracentric) positions R0 = 84 and 112 mm at particular values of V(R0). These results provide the first experimental verification and a proof of principle of the utility of such a paracentric HDA, while demonstrating its advantages over the conventional HDA: greater dispersion with reduced angular aberrations resulting in better energy resolution without the use of any additional fringing field correction electrodes. Supporting simulations of the entire lens plus HDA spectrometer are also provided and mostly found to be within 20%-30% of experimental values. The paracentric HDA is expected to provide a lower cost and/or more compact alternative to the conventional HDA particularly useful in modern applications utilizing a position sensitive detector.

Dogan, M.; Ulu, M.; Gennarakis, G. G.; Zouros, T. J. M.

2013-04-01

257

Experimental investigations of the use of an erbium:YAG laser on temporomandibular joint (TMJ) structures: first experimental results  

NASA Astrophysics Data System (ADS)

The following paper introduces the results of an interdisciplinary research project. With the aid of photomacroscopic examination, light and scanning electron microscope investigations, changes to temporomandibular joint structures were detected in vitro after irradiation with an Erbium:YAG laser system. The solid-state Erbium:YAG laser, operating at a wavelength of 2.94 micrometers was used in the normal- spiking mode. The free-running laser beam was focussed onto freshly excised porcine tissue samples using a 108-mm sapphire lens. In this study the output was generally pulsed at a repetition rate of 4 Hz, with a pulse duration varying from 120 microsecond(s) to 500 microsecond(s) . Between 50 mJ and 500 mJ per pulse were applied to create pinpoint lesions. The optimum average energy density and pulse duration of the Erbium:YAG laser radiation for the purpose of TMJ-surgery (as far as it concerns meniscus and articulating facets) - which means efficient etch rate and minimal adjacent injury - seems to be about 24-42 J/cm2 and 120 microsecond(s) -240 microsecond(s) , respectively.

Nuebler-Moritz, Michael; Niederdellmann, Herbert; Hering, Peter; Deuerling, Christian; Dammer, Ralf; Behr, M.

1995-04-01

258

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

259

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

260

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

261

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

262

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

263

Experimental results from a diagnostic beamline for the PBX-M experiment  

SciTech Connect

The experimental performance of a high-brightness neutral-beam system is described which has been designed and manufactured by Culham Laboratory under contract to the Princeton Plasma Physics Laboratory. The neutral beam serves as a diagnostic on the PBX-M experiment and is used to perform studies of high-beta, bean-shaped, neutral-beam-heated plasmas, and plasma-current profile shaping using ion Bernstein wave and lower hybrid rf systems. A maximum extracted current of {similar to}2.7 A of positive hydrogen ions at 80 keV has been obtained from a multiaperture extraction system. The full-energy H{sup 0}-equivalent neutral-current density measured 370 cm from the extraction plane was {similar to}6 mA cm{sup {minus}2}.

Coupland, J.R.; Gray, I.L.S.; Hancock, O.J.; Martel, K.P.; Mepham, J.W.; Preest, A.A. (Culham Laboratory (Euratom/UKAEA Fusion Association), Abingdon, Oxon, OX14 3DB, England (GB)); Kugel, H.W.; Kaita, R. (Princeton Plasma Physics Laboratory, Princeton University, P.O. Box 451, Princeton, New Jersey 08544 (USA))

1990-01-01

264

Broadband optical cavities for infrared free electron lasers Analysis and preliminary experimental results  

NASA Astrophysics Data System (ADS)

One advantage of the free electron laser (FEL) is related to its capability for broadband tuning through variation of either the wiggler magnetic field strength or the electronic energy. As in any laser system, broadband optical feedback is needed for the practical attainment of broadband tunability. Cutolo and Madey (1984) have concluded that, in the IR, broadband optical feedback could best be accomplished through the use of metallic mirrors in a stable optical cavity configuration. As a solution to the output coupling problem, it has been proposed to employ an intracavity acoustooptic output coupler. A description has been given of several different possible configurations for the output coupler, and an analysis of thermal effects and effects of finite bandwidth has been conducted. The present investigation has the aim to provide a description of the complete design of the 2-10-micron optical cavity for the Mark III FEL, taking into account the experimental performance of the acoustooptic couplers.

Cutolo, A.; Khuri-Yakub, B. T.; Madey, J. M. J.

1984-09-01

265

Importance of dose-rate and cell proliferation in the evaluation of biological experimental results  

NASA Technical Reports Server (NTRS)

The nuclei of cells within the bodies of astronauts traveling on extended missions outside the geomagnetosphere will experience single traversals of particles with high Linear Energy Transfer (LET) (e.g., one iron ion per one hundred years, on average) superimposed on a background of tracks with low LET (approximately one proton every two to three days, and one helium ion per month). In addition, some cell populations within the body will be proliferating, thus possibly providing increasing numbers of cells with 'initiated' targets for subsequent radiation hits. These temporal characteristics are not generally reproduced in laboratory experimental protocols. Implications of the differences in the temporal patterns of radiation delivery between conventionally designed radiation biology experiments and the pattern to be experienced in space are examined and the importance of dose-rate and cell proliferation are pointed out in the context of radiation risk assessment on long mission in space.

Curtis, S. B.

1994-01-01

266

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

NASA Technical Reports Server (NTRS)

A new supersonic retropropulsion experimental effort, intended to provide code validation data, was recently completed in the Langley Research Center Unitary Plan Wind Tunnel Test Section 2 over the Mach number range from 2.4 to 4.6. The experimental model was designed using insights gained from pre-test computations, which were instrumental for sizing and refining the model to minimize tunnel wall interference and internal flow separation concerns. A 5-in diameter 70-deg sphere-cone forebody with a roughly 10-in long cylindrical aftbody was the baseline configuration selected for this study. The forebody was designed to accommodate up to four 4:1 area ratio supersonic nozzles. Primary measurements for this model were a large number of surface pressures on the forebody and aftbody. Supplemental data included high-speed Schlieren video and internal pressures and temperatures. The run matrix was developed to allow for the quantification of various sources of experimental uncertainty, such as random errors due to run-to-run variations and bias errors due to flow field or model misalignments. Preliminary results and observations from the test are presented, while detailed data and uncertainty analyses are ongoing.

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

2011-01-01

267

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

PubMed

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

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

2013-11-01

268

Non-local spatial frequency response of photopolymer materials containing chain transfer agents: II. Experimental results  

NASA Astrophysics Data System (ADS)

In part I of this paper the non-local photo-polymerization driven diffusion model was extended to include the kinetics of chain transfer and re-initiation, in order to analyse the effects of chain transfer agents on the system kinetics and to study their use in reducing the average polymer chain length in free-radical based photopolymer materials. Based on these results, it is proposed that one possible way to improve the material response at high spatial frequency is the addition of chain transfer agents. In this paper, the validity of the proposed model is examined by applying it to fit experimental data for an acrylamide/polyvinyl alcohol (AA/PVA) layer containing two different types of chain transfer agent (CTA): sodium formate (HCOONa) and 1-mercapto-2-propanol (CH3CH(OH)CH2SH). The effects on decreasing the average polymer chain length formed, by the addition of chain transfer agent, which in turn reduces the non-local response of the material, are demonstrated. These reductions are shown to be accompanied by improved high spatial frequency response. Key material parameters are extracted by numerically fitting experimentally measured refractive index modulation growth curves using the model. Further independent experimental confirmation of the reduction in the average polymer molecular weight is provided using a diffusion based holographic technique.

Guo, Jinxin; Gleeson, Michael R.; Liu, Shui; Sheridan, John T.

2011-09-01

269

Thermodynamic prediction of glycine polymerization as a function of temperature and pH consistent with experimentally obtained results.  

PubMed

Prediction of the thermodynamic behaviors of biomolecules at high temperature and pressure is fundamental to understanding the role of hydrothermal systems in the origin and evolution of life on the primitive Earth. However, available thermodynamic dataset for amino acids, essential components for life, cannot represent experimentally observed polymerization behaviors of amino acids accurately under hydrothermal conditions. This report presents the thermodynamic data and the revised HKF parameters for the simplest amino acid "Gly" and its polymers (GlyGly, GlyGlyGly and DKP) based on experimental thermodynamic data from the literature. Values for the ionization states of Gly (Gly(+) and Gly(-)) and Gly peptides (GlyGly(+), GlyGly(-), GlyGlyGly(+), and GlyGlyGly(-)) were also retrieved from reported experimental data by combining group additivity algorithms. The obtained dataset enables prediction of the polymerization behavior of Gly as a function of temperature and pH, consistent with experimentally obtained results in the literature. The revised thermodynamic data for zwitterionic Gly, GlyGly, and DKP were also used to estimate the energetics of amino acid polymerization into proteins. Results show that the Gibbs energy necessary to synthesize a mole of peptide bond is more than 10 kJ mol(-1) less than previously estimated over widely various temperatures (e.g., 28.3 kJ mol(-1) ? 17.1 kJ mol(-1) at 25 °C and 1 bar). Protein synthesis under abiotic conditions might therefore be more feasible than earlier studies have shown. PMID:24652580

Kitadai, Norio

2014-04-01

270

Silicon Carbide Epitaxy in a Vertical CVD Reactor: Experimental Results and Numerical Process Simulation  

NASA Astrophysics Data System (ADS)

In this paper an overview is given on the epitaxial growth of SiC in a vertical CVD reactor. Results concerning impurity incorporation and ways to achieve background doping levels as low as 1014 cm - 3 are discussed. Precise control of the C/Si ratio in the gas phase, which is easily achieved in the described reactor, and the use of reduced pressure, lead to good control of dopant incorporation over more than three orders of magnitude, and smooth surface morphology at growth rates higher than 5 m/h. Doping variations <+/-12% across 35 mm wafers can routinely be obtained. The quality of the epilayers is proven by electrical brakdown fields as high as 2×106 V/cm at NA - ND = 5×10 - 15 cm - 3 achieved in both pn and Schottky diodes and an electron mobility higher than 700 cm2/Vs at 300 K (4H-SiC) estimated from the on-resistance of these test devices. Another important experimental boundary condition, the influence of the gas composition at the end of the epitaxial growth process on the surface properties of the epitaxial layer, is described. It will be shown that surfaces nearly resistant against oxidation can be generated in a hydrogen free atmosphere. As a second main topic of this paper, results of an elaborate numerical process simulation will be described including both fluid mechanical and chemical behavior. The influence of the main process parameters like total flow, chamber pressure, and rotation speed on the stability of the flow was investigated. The results achieved are compared with experimental observations showing excellent agreement. The experimental observation of an irradiant layer in the gas phase in front of the wafer under typical process conditions is explained with the help of the numerical model. The usefulness of this specific feature for the optimization of process conditions is discussed.

Rupp, R.; Makarov, Yu. N.; Behner, H.; Wiedenhofer, A.

1997-07-01

271

Experimental and Analytical Studies on Pyroelectric Waste Heat Energy Conversion  

E-print Network

21st Intersociety Energy Conversion Engineering Conference,Energy Conversion by Felix Lee Master of Science in Mechanical EngineeringEnergy Conversion A thesis submitted in partial satisfaction of the requirements for the degree Master of Science in Mechanical Engineering

Lee, Felix

2012-01-01

272

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

NASA Astrophysics Data System (ADS)

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

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

2010-05-01

273

A Comparison of Experimental and Theoretical Results for Labyrinth Gas Seals. Ph.D. Thesis  

NASA Technical Reports Server (NTRS)

The basic equations are derived for a two control volume model for compressible flow in a labyrinth seal. The flow is assumed to be completely turbulent and isoenergetic. The wall friction factors are determined using the Blasius formula. Jet flow theory is used for the calculation of the recirculation velocity in the cavity. Linearized zeroth and first order perturbation equations are developed for small motion about a centered position by an expansion in the eccentricity ratio. The zeroth order pressure distribution is found by satisfying the leakage equation. The circumferential velocity distribution is determined by satisfying the momentum equations. The first order equations are solved by a separation of variable solution. Integration of the resultant pressure distribution along and around the seal defines the reaction force developed by the seal and the corresponding dynamic coefficients. The results of this analysis are compared to experimental test results.

Scharrer, Joseph Kirk

1987-01-01

274

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

NASA Technical Reports Server (NTRS)

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.

1984-01-01

275

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

NASA Astrophysics Data System (ADS)

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

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

2010-06-01

276

Investigation of sonar transponders for offshore wind farms: modeling approach, experimental setup, and results.  

PubMed

The installation of offshore wind farms in the German Exclusive Economic Zone requires the deployment of sonar transponders to prevent collisions with submarines. The general requirements for these systems have been previously worked out by the Research Department for Underwater Acoustics and Marine Geophysics of the Bundeswehr. In this article, the major results of the research project "Investigation of Sonar Transponders for Offshore Wind Farms" are presented. For theoretical investigations a hybrid approach was implemented using the boundary element method to calculate the source directivity and a three-dimensional ray-tracing algorithm to estimate the transmission loss. The angle-dependence of the sound field as well as the weather-dependence of the transmission loss are compared to experimental results gathered at the offshore wind farm alpha ventus, located 45?km north of the island Borkum. While theoretical and experimental results are in general agreement, the implemented model slightly underestimates scattering at the rough sea surface. It is found that the source level of 200?dB re 1??Pa at 1?m is adequate to satisfy the detectability of the warning sequence at distances up to 2 NM (?3.7?km) within a horizontal sector of ±60° if realistic assumptions about signal-processing and noise are made. An arrangement to enlarge the angular coverage is discussed. PMID:24180764

Fricke, Moritz B; Rolfes, Raimund

2013-11-01

277

Raman scattering in crystals excited in total reflection condition: Theory and experimental results  

NASA Astrophysics Data System (ADS)

In this paper we present a macroscopic theory of the Raman scattering excited in condition of total reflection (RSTR) at the interface between two isotropic transparent solids. We obtain a general expression of the RSTR efficiency and discuss its angular dependence. We show that such a kind of scattering is suitable for studying the bulk excitations in a very thin region under the interface as well as the surface excitations in crystals. A comparison between theory and preliminary experimental results for a sapphire-NaBrO 3 interface is reported.

Mattei, Giorgio; Fornari, Bruno; Pagannone, Mario

1980-10-01

278

Active vibration absorber for the CSI evolutionary model - Design and experimental results. [Controls Structures Interaction  

NASA Technical Reports Server (NTRS)

The development of control of large flexible structures technology must include practical demonstrations to aid in the understanding and characterization of controlled structures in space. To support this effort, a testbed facility has been developed to study practical implementation of new control technologies under realistic conditions. The paper discusses the design 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. Experimental results in the presence of these factors are presented and discussed. The robustness of this design under model uncertainty is demonstrated.

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

1991-01-01

279

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

280

Experimental results of field windings and concepts of rotor component development of superconducting generator  

NASA Astrophysics Data System (ADS)

Field windings of superconducting generators are wound in slots which are cut on the outer surface of a support tube, and they are supported by wedges against centrifugal and electromagnetic forces. To improve reliability of field windings, ac losses due to flux change, and ohmic losses due to the winding, connections must be small and field windings must be tightly compressed by wedges. This paper presents experimental results of ac losses, ohmic losses, compression-displacement measurements of field windings, and design concepts of the present rotor-component development project.

Ueda, A.; Hirao, T.; Hatanaka, H.; Morita, M.

1987-09-01

281

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

282

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

283

Experimental results and first 22Na source image reconstruction by two prototype modules in coincidence of a liquid xenon positron emission tomograph for small animal imaging  

NASA Astrophysics Data System (ADS)

A detector with a very specific design using liquid Xenon (LXe) in the scintillation mode is studied for Positron Emission Tomography (PET) of small animals. Two prototype modules equipped with Position Sensitive Photo Multiplier Tubes (PSPMTs) operating in the VUV range (178 nm) and at 165 K were built and studied in coincidence. This paper reports on energy, time and spatial resolution capabilities of this experimental test bench. Furthermore, these experimental results were used to perform the first image reconstruction of a 22Na source placed in the experimental setup.

Gallin-Martel, M.-L.; Grondin, Y.; Gac, N.; Carcagno, Y.; Gallin-Martel, L.; Grondin, D.; Marton, M.; Muraz, J.-F.; Rossetto, O.; Vezzu, F.

2012-08-01

284

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

285

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

286

Monte Carlo calculations and experimental results of Bonner spheres systems with a new cylindrical Helium-3 proportional counter  

NASA Astrophysics Data System (ADS)

The experimental results on neutron energy spectra, integral fluences and equivalent dose measurements performed by means of a Bonner sphere system placed inside the containment building of the Vandellòs II Nuclear Power Plant (Tarragona, Spain) are presented. The equivalent dose results obtained with this system are compared to those measured with different neutron area detectors (Berthold, Dineutron, Harwell). A realistic geometry model of the Bonner sphere system with a new cylindrical counter type "F" (0,5NH1/1KI—Eurisys Mesures) and with a set of eight polyethylene moderating spheres is described in detail. The response function in fluence of this new device, to mono-energetic neutrons from thermal energy to 20 MeV, is calculated by the MCNP-4B code for each moderator sphere. The system has been calibrated at IPSN Cadarache facility for ISO Am-Be calibrated source and thermal neutron field, then the response functions were confirmed by measurements at PTB (Germany) for ISO recommended energies of mono-energetic neutrons and with the CANEL IPSN facility which simulates realistic fields.

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

2002-01-01

287

Theoretical versus experimental results for the rotordynamic coefficients of eccentric, smooth, gas annular seal annular gas seals  

NASA Technical Reports Server (NTRS)

This viewgraph presentation presents the following results: (1) The analytical results overpredict the experimental results for the direct stiffness values and incorrectly predict increasing stiffness with decreasing pressure ratios. (2) Theory correctly predicts increasing cross-coupled stiffness, K(sub YX), with increasing eccentricity and inlet preswirl. (3) Direct damping, C(sub XX), underpredicts the experimental results, but the analytical results do correctly show that damping increases with increasing eccentricity. (4) The whirl frequency values predicted by theory are insensitive to changes in the static eccentricity ratio. Although these values match perfectly with the experimental results at 16,000 rpm, the results at the lower speed do not correspond. (5) Theoretical and experimental mass flow rates match at 5000 rpm, but at 16,000 rpm the theoretical results overpredict the experimental mass flow rates. (6) Theory correctly shows the linear pressure profiles and the associated entrance losses with the specified rotor positions.

Childs, Dara W.; Alexander, Chis

1994-01-01

288

Experimental study of a transformer with superconducting elements for fault current limitation and energy redistribution  

NASA Astrophysics Data System (ADS)

Numerous proposed and developed superconducting fault current limiters and self-limiting transformers limit successfully fault currents but do not provide uninterrupted supplying of consumers. A design investigated in the work combines the functions of a conventional transformer with the functions of fast energy redistribution and fault protection. The device constitutes a transformer containing an additional high-temperature superconducting (HTS) coil short-circuited by a thin film HTS switching element. Fault current limitation and redistribution of the power flow to a standby line are achieved as a result of a fast transition of the superconducting switching element from the superconducting into the normal state. Transient and steady-state characteristics were experimentally investigated. A mathematical model of the device operation was proposed, and the calculated results were found to be in good agreement with the experimental data. The application field and basic requirements to such devices were discussed and it was shown that the proposed device meets these requirements.

Meerovich, V.; Sokolovsky, V.

2005-08-01

289

Numerical and experimental investigation on frosting of energy-recovery ventilator  

NASA Astrophysics Data System (ADS)

Frosting of energy-recovery ventilators results in two major problems: increase of pressure losses and reduction of heat transfer rates. Frost formation of heat and mass exchangers used in these ventilation systems is investigated both experimentally and numerically. A numerical model for the prediction of the thermal behavior of the exchanger is presented. The model is validated with experimental data and is then employed to conduct a parametric study. Results indicate that the absolute humidity is the prevailing parameter for characterizing the frosting phenomenon. A frost-mass-fraction chart is established in terms of the absolute humidity of the warm exhaust stream and of the temperature of the cold supply stream. The effect of time and mass flowrate is also evaluated. The transient three-dimensional model shows that the absolute humidity and the temperature of both air flows vary nonlinearly in the frosted zone.

Bilodeau, Stephane; Mercadier, Yves; Brousseau, Patrick

290

Parametric study of horizontally vibrated grain packings: comparison between Discrete Element Method and experimental results.  

PubMed

Numerical and experimental studies have been undertaken to analyze three parameters controlling the compaction of granular media submitted to sinusoidal horizontal vibrations. We have characterized the influence of the dimensionless acceleration ?, the geometry of the container and the friction coefficients on the grain velocities and on the packing densities. Above a critical acceleration ?, the velocities increases with ?. For low values of ?, the surface layers are compacted, whereas the bottom layers remain at their initial density. For high values of ?, the bottom layers get compacted, the surface layers are fluidized so that the bulk dynamic and relaxed densities decreased. In the same way, the effect of the dimensions of the container and of the friction coefficients on the packing properties has been studied for given heights of sand, acceleration and frequency. It has been shown that the influence of the two last parameters is similar to that of acceleration. The numerical results given by the Discrete Element Method appear to be in good agreement with experimental results. PMID:21744301

Nadler, S; Bonnefoy, O; Chaix, J-M; Thomas, G; Gelet, J-L

2011-07-01

291

Analysis and comparison of experimental and simulated results for an omnidirectional free space optical receiver architecture  

NASA Astrophysics Data System (ADS)

Lasercomm or Free Space Optical (FSO) communication has the potential to provide fiber optic data rates without the need for wired physical connectivity. This paper investigates the feasibility of an Omnidirectional FSO (O-FSO) communications link that utilizes fiber bundles for improved omni-directionality and compares experimental data with modeled results. Current state of the art O-FSO link ranges are limited to 100 meters or so, with data rates of only a few100 kbits/sec. The proposed architecture is formed from commercially available fiber bundle that collects omnidirectional light due to the hemispheric nature of the fiber bundle by exploiting the acceptance cones of the individual fiber exposed to the optical radiation. The experimental transmitter is composed of an LED source that is driven by an On-Off-Keying signal. This paper presents the received optical power while varying the range between the transmitter and receiver. The omni-directionality of this architecture is also verified. The measured results are then compared to the model predictions for omni-directionality and range.

Murshid, Syed H.; Lovell, Gregory L.; Finch, Michael F.

2014-09-01

292

Epistemology and expectations survey about experimental physics: Development and initial results  

NASA Astrophysics Data System (ADS)

In response to national calls to better align physics laboratory courses with the way physicists engage in research, we have developed an epistemology and expectations survey to assess how students perceive the nature of physics experiments in the contexts of laboratory courses and the professional research laboratory. The Colorado Learning Attitudes about Science Survey for Experimental Physics (E-CLASS) evaluates students' epistemology at the beginning and end of a semester. Students respond to paired questions about how they personally perceive doing experiments in laboratory courses and how they perceive an experimental physicist might respond regarding their research. Also, at the end of the semester, the E-CLASS assesses a third dimension of laboratory instruction, students' reflections on their course's expectations for earning a good grade. By basing survey statements on widely embraced learning goals and common critiques of teaching labs, the E-CLASS serves as an assessment tool for lab courses across the undergraduate curriculum and as a tool for physics education research. We present the development, evidence of validation, and initial formative assessment results from a sample that includes 45 classes at 20 institutions. We also discuss feedback from instructors and reflect on the challenges of large-scale online administration and distribution of results.

Zwickl, Benjamin M.; Hirokawa, Takako; Finkelstein, Noah; Lewandowski, H. J.

2014-06-01

293

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

SciTech Connect

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

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

1996-04-15

294

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

295

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

296

The Langley Research Center CSI phase-0 evolutionary model testbed-design and experimental results  

NASA Technical Reports Server (NTRS)

A testbed for the development of Controls Structures Interaction (CSI) technology is described. The design philosophy, capabilities, and early experimental results are presented to introduce some of the ongoing CSI research at NASA-Langley. The testbed, referred to as the Phase 0 version of the CSI Evolutionary model (CEM), is the first stage of model complexity designed to show the benefits of CSI technology and to identify weaknesses in current capabilities. Early closed loop test results have shown non-model based controllers can provide an order of magnitude increase in damping in the first few flexible vibration modes. Model based controllers for higher performance will need to be robust to model uncertainty as verified by System ID tests. Data are presented that show finite element model predictions of frequency differ from those obtained from tests. Plans are also presented for evolution of the CEM to study integrated controller and structure design as well as multiple payload dynamics.

Belvin, W. K.; Horta, Lucas G.; Elliott, K. B.

1991-01-01

297

Experimental and raytrace results for throat-to-throat compound parabolic concentrators  

NASA Technical Reports Server (NTRS)

Compound parabolic concentrators are nonimaging cone-shaped optics with useful angular transmission characteristics. Two cones used throat-to-throat accept radiant flux within one well-defined acceptance angle and redistribute it into another. If the entrance cone is fed with Lambertian flux, the exit cone produces a beam whose half-angle is the exit cone's acceptance angle and whose cross section shows uniform irradiance from near the exit mouth to infinity. (The pair is a beam angle transformer). The design of one pair of cones is discussed, also an experiment to map the irradiance of the emergent beam, and a raytracing program which models the cones fed by Lambertian flux. Experimental results compare favorably with raytrace results.

Leviton, D. B.; Leitch, J. W.

1986-01-01

298

Experimental results of exothermic reaction with concentration gradient catalyst in a solar chemical heat pump  

SciTech Connect

Solar chemical heat pump can upgrade the low temperature solar heat about 80 C to about 150--200 C by the reversible chemical reactions of 2-propanol/acetone/hydrogen, which are composed of endothermic and exothermic reactions. In the exothermic process of above reaction, a temperature peak occurs near the inlet of reaction zone in the case of arranging catalyst uniformly. Such a temperature distribution is not suitable for heat exchange. Therefore, the authors arrange the concentration of catalyst gradationally so as not to occur the temperature peak. In this paper, experimental results of exothermic reaction with concentration gradient catalyst in a double tubular exothermic reactor are presented. These results show that the arrangement of concentration gradient catalyst has the possibility about the temperature control in the catalytic reactor.

Takashima, Takumi; Doi, Takuya; Ando, Yuji; Tanaka, Tadayoshi [Electrotechnical Lab., Tsukuba, Ibaraki (Japan); Miyahara, Ryosuke; Kamoshida, Junji [Shibaura Inst. of Tech., Omiya, Saitama (Japan)

1997-12-31

299

An iterative CFD and mechanical brush seal model and comparison with experimental results  

SciTech Connect

The position of the bristles within a brush seal is dictated by the pressure distribution within the seal, which is itself influenced by the position of the bristle matrix. In order to predict mass flows, pressure capabilities, bristle displacements, stresses, and contact loads at the rotor interface, a technique for iterating between a CFD and a mechanical model has been developed. The iterative technique is used to model the behavior of seals with an initial build clearance, where the application of pressure causes a change in the position of the bristle matrix. Frictional effects between neighboring bristles and at the backing ring influence the behavior of the bristles and these are accounted for within the mechanical part of the model. Results are presented and discussed for seals of both initial build clearance and interference. The mathematical predictions for flow, contact loads at the rotor interface, and the nature of the bristles displacements are compared with experimental results.

Chen, L.H.; Wood, P.E.; Jones, T.V.; Chew, J.W.

1999-10-01

300

Beam-waveguide antenna performance predictions with comparisons to experimental results  

NASA Technical Reports Server (NTRS)

An overview of a NASA/JPL antenna project is presented, with specific focus on the methodology used to predict the microwave performance of a 34-m-diameter beam-waveguide (BWG) reflector antenna, designated DSS 13 (Deep Space Station 13). DSS 13 is the R&D facility serving the NASA/JPL Deep Space Network. Microwave performance predictions as well as a summary of test results for the antenna are given. The antenna has Cassegrain and centerline BWG operating modes at X-band (8.450-GHz) and Ka-band (32-GHz) frequencies. The performance predictions regarding antenna area efficiencies, corresponding beampeak gains, and for several (but not all) operating noise temperatures are found to agree reasonably well with the corresponding experimental results.

Bathker, Dan A.; Veruttipong, Watt; Otoshi, Tom Y.; Cramer, Paul W., Jr.

1992-01-01

301

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

302

Experimental realization of magnetic energy concentration and transmission at a distance by metamaterials  

NASA Astrophysics Data System (ADS)

Concentrating magnetic energy in a desired volume is an important requirement for many technologies. Here, we experimentally realize a superconductor-ferromagnetic metamaterial that allows to concentrate the magnetostatic energy in its interior and in other situations to amplify the energy in its exterior. We show that surrounding two distant current loops with two such metamaterials enhance the magnetostatic coupling between them. We also demonstrate that a ferromagnetic-only metamaterial, without superconducting parts, achieves these properties with only a slight decrease in performance. Results may be applied to increase the sensitivity of magnetic sensors or for enhancing wireless power transmission, where efficiency depends critically on the magnetic coupling strength between source and receiver.

Prat-Camps, Jordi; Navau, Carles; Sanchez, Alvaro

2014-12-01

303

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

304

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

SciTech Connect

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

Innocenzi, V., E-mail: valentina.innocenzi1@univaq.it; De Michelis, I.; Ferella, F.; Vegliò, F.

2013-11-15

305

Development of Revised Energy Standards for Texas Buildings: Preliminary Results  

E-print Network

-specific equations will be applied to an expanded set of exclusively Texas locations. Theae improved equations will provide lore reliable results for Texaa but will not affect the structure or format of the calculation and caplience procedures. The second step... for the reduction in electric lighting energy resulting from automatic controls in zones adjacent to wind- or skylights. The control credit takem the form of an increased lighting power density allowance. The envelope Basic Requirements specify a calculation...

Hunn, B. D.; Jones, J. W.; Silver, S. C.

1988-01-01

306

A prediction of energy savings resulting from building infiltration control  

E-print Network

is not considered), annual energy savings were found in a warm climate as high as 17%, and as high as 30% in a cooler climate. The results were less promising when compared against the performance of a building experiencing natural, or not induced, airflow (and heat...

McWatters, Kenneth Rob

2012-06-07

307

Experimental results of fingerprint comparison validity and reliability: A review and critical analysis.  

PubMed

Our purpose in this article is to determine whether the results of the published experiments on the accuracy and reliability of fingerprint comparison can be generalized to fingerprint laboratory casework, and/or to document the error rate of the Analysis-Comparison-Evaluation (ACE) method. We review the existing 13 published experiments on fingerprint comparison accuracy and reliability. These studies comprise the entire corpus of experimental research published on the accuracy of fingerprint comparisons since criminal courts first admitted forensic fingerprint evidence about 120years ago. We start with the two studies by Ulery, Hicklin, Buscaglia and Roberts (2011, 2012), because they are recent, large, designed specifically to provide estimates of the accuracy and reliability of fingerprint comparisons, and to respond to the criticisms cited in the National Academy of Sciences Report (2009). Following the two Ulery et al. studies, we review and evaluate the other eleven experiments, considering problems that are unique to each. We then evaluate the 13 experiments for the problems common to all or most of them, especially with respect to the generalizability of their results to laboratory casework. Overall, we conclude that the experimental designs employed deviated from casework procedures in critical ways that preclude generalization of the results to casework. The experiments asked examiner-subjects to carry out their comparisons using different responses from those employed in casework; the experiments presented the comparisons in formats that differed from casework; the experiments enlisted highly trained examiners as experimental subjects rather than subjects drawn randomly from among all fingerprint examiners; the experiments did not use fingerprint test items known to be comparable in type and especially in difficulty to those encountered in casework; and the experiments did not require examiners to use the ACE method, nor was that method defined, controlled, or tested in these experiments. Until there is significant progress in defining and measuring the difficulty of fingerprint test materials, and until the steps to be followed in the ACE method are defined and measurable, we conclude that new experiments patterned on these existing experiments cannot inform the fingerprint profession or the courts about casework accuracy and errors. PMID:25278202

Haber, Ralph Norman; Haber, Lyn

2014-09-01

308

Numerical Predictions and Experimental Results of Air Flow in a Smooth Quarter-Scale Nacelle  

SciTech Connect

Fires in aircraft engine nacelles must be rapidly suppressed to avoid loss of life and property. The design of new and retrofit suppression systems has become significantly more challenging due to the ban on production of Halon 1301 for environmental concerns. Since fire dynamics and the transport of suppressants within the nacelle are both largely determined by the available air flow, efforts to define systems using less effective suppressants greatly benefit from characterization of nacelle air flow fields. A combined experimental and computational study of nacelle air flow therefore has been initiated. Calculations have been performed using both CFD-ACE (a Computational Fluid Dynamics (CFD) model with a body-fitted coordinate grid) and WLCAN (a CFD-based fire field model with a Cartesian ''brick'' shaped grid). The flow conditions examined in this study correspond to the same Reynolds number as test data from the full-scale nacelle simulator at the 46 Test Wing. Pre-test simulations of a quarter-scale test fixture were performed using CFD-ACE and WLCAN prior to fabrication. Based on these pre-test simulations, a quarter-scale test fixture was designed and fabricated for the purpose of obtaining spatially-resolved measurements of velocity and turbulence intensity in a smooth nacelle. Post-test calculations have been performed for the conditions of the experiment and compared with experimental results obtained from the quarter-scale test fixture. In addition, several different simulations were performed to assess the sensitivity of the predictions to the grid size, to the turbulence models, and to the use of wall functions. In general, the velocity predictions show very good agreement with the data in the center of the channel but deviate near the walls. The turbulence intensity results tend to amplify the differences in velocity, although most of the trends are in agreement. In addition, there were some differences between WLCAN and CFD-ACE results in the angled wall regions due to the Cartesian grid structure used by the WLCAN code. Also, the experimental data tended t o show poorer resolution near the walls of the transition ducts. The increased uncertainty in the data highlights some of the challenges in getting data near the walls due to the low signal to noise ratio. Overall, this effort provided a benchmark case for both the WLCAN and CFD-ACE codes for the application of interest.

BLACK, AMALIA R.; SUO-ANTTILA, JILL M.; GRITZO, LOUIS A.; DISIMILE, PETER J.; TUCKER, JAMES R.

2002-06-01

309

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

310

Thermodiffusion in concentrated ferrofluids: Experimental and numerical results on magnetic thermodiffusion  

SciTech Connect

Ferrofluids consist of magnetic nanoparticles dispersed in a carrier liquid. Their strong thermodiffusive behaviour, characterised by the Soret coefficient, coupled with the dependency of the fluid's parameters on magnetic fields is dealt with in this work. It is known from former experimental investigations on the one hand that the Soret coefficient itself is magnetic field dependent and on the other hand that the accuracy of the coefficient's experimental determination highly depends on the volume concentration of the fluid. The thermally driven separation of particles and carrier liquid is carried out with a concentrated ferrofluid (? = 0.087) in a horizontal thermodiffusion cell and is compared to equally detected former measurement data. The temperature gradient (1 K/mm) is applied perpendicular to the separation layer. The magnetic field is either applied parallel or perpendicular to the temperature difference. For three different magnetic field strengths (40 kA/m, 100 kA/m, 320 kA/m) the diffusive separation is detected. It reveals a sign change of the Soret coefficient with rising field strength for both field directions which stands for a change in the direction of motion of the particles. This behaviour contradicts former experimental results with a dilute magnetic fluid, in which a change in the coefficient's sign could only be detected for the parallel setup. An anisotropic behaviour in the current data is measured referring to the intensity of the separation being more intense in the perpendicular position of the magnetic field: S{sub T?} = ?0.152 K{sup ?1} and S{sub T?} = ?0.257 K{sup ?1} at H = 320 kA/m. The ferrofluiddynamics-theory (FFD-theory) describes the thermodiffusive processes thermodynamically and a numerical simulation of the fluid's separation depending on the two transport parameters ?{sub ?} and ?{sub ?} used within the FFD-theory can be implemented. In the case of a parallel aligned magnetic field, the parameter can be determined to ?{sub ?} = (2.8;?9.1;?11.2)?×?10{sup ?11}?·?D{sub ?} kg/(A{sup 2}m) for the different field strengths and in dependence on the magnetic diffusion coefficient D{sub ?}. An adequate fit in the perpendicular case is not possible, by ?{sub ?} = 1?×?10{sup ?17} kg/(Am{sup 2}) a rather good agreement between numerical and experimental data can be found for a field strength of 40 kA/m, a change in the coefficient's sign in the perpendicular setup is not numerically determinable via this theory. The FFD-theory is only partly applicable to calculate the concentration profile in concentrated magnetic fluids established due to a temperature gradient and magnetic field applied.

Sprenger, Lisa, E-mail: Lisa.Sprenger@tu-dresden.de; Lange, Adrian; Odenbach, Stefan [Institute of Fluid Mechanics, Chair of Magnetofluiddynamics, Measuring and Automation Technology, TU Dresden, 01062 Dresden (Germany)] [Institute of Fluid Mechanics, Chair of Magnetofluiddynamics, Measuring and Automation Technology, TU Dresden, 01062 Dresden (Germany)

2014-02-15

311

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

312

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

313

Experimental Studies of Energy Trends Development of Artificial Ecosystems and Their Links  

NASA Astrophysics Data System (ADS)

Two types of artificial ecosystems with different trophic links have been used for experimental studies of energy trends development and microevolution procecces 1 Microbial populations in artificial ecosystems AES for water purification are the most active transforming organisms and consumers of organic substances of wastes In our experiments we observed different changes in Active Sludge AS structure and populations composition connected with changes in environmental factors and self-development of AS As a result of biological adaptations unutilized substrate concentration decreased in many cases The exact structure of microbial community also changed the biological diversity decreased But in all experiments we observed certain increase of fluxes of energy utilized by the system 2 In experiments with continuous microbial cultures we used Escherichia coli genetically engineered strains They contain in plasmids the cloned genes of marine photobacteria bioluminescence and genes of green fluorescent protein GFP which expression level can be easily changed and controlled We observed kinetic diversity of evolutionary transfers in systems But general mechanisms characterized the increase of used energy flow by bacterial populations under study According to our experimental data at spontaneous development and microevolution processes heat dissipation characterizing the rate of entropy growth increased rather then decreased or maintained steady as G Nikolis and I Prigogin believed The results require further development

Somova, L. A.; Pechurkin, N. S.; Brilkov, A. V.; Loginov, I. A.; Morozova, E. V.

314

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

315

Damping as a result of piezoelectric energy harvesting  

NASA Astrophysics Data System (ADS)

Systems that harvest or scavenge energy from their environments are of considerable interest for use in remote power supplies. A class of such systems exploits the motion or deformation associated with vibration, converting the mechanical energy to electrical, and storing it for later use; some of these systems use piezoelectric materials for the direct conversion of strain energy to electrical energy. The removal of mechanical energy from a vibrating structure necessarily results in damping. This research addresses the damping associated with a piezoelectric energy harvesting system that consists of a full-bridge rectifier, a filter capacitor, a switching DC-DC step-down converter, and a battery. Under conditions of harmonic forcing, the effective modal loss factor depends on: (1) the electromechanical coupling coefficient of the piezoelectric system; and (2) the ratio of the rectifier output voltage during operation to its maximum open-circuit value. When the DC-DC converter is maximizing power flow to the battery, this voltage ratio is very nearly 1/2, and the loss factor depends only on the coupling coefficient. Experiments on a base-driven piezoelectric cantilever, having a system coupling coefficient of 26%, yielded an effective loss factor for the fundamental vibration mode of 2.2%, in excellent agreement with theory.

Lesieutre, G. A.; Ottman, G. K.; Hofmann, H. F.

2004-01-01

316

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

317

Modelling Viscoelastic Behaviour of Polymer by A Mixed Velocity, Displacement Formulation - Numerical and Experimental Results  

SciTech Connect

The objective of this work is to model the viscoelastic behaviour of polymer from the solid state to the liquid state. With this objective, we perform experimental tensile tests and compare with simulation results. The chosen polymer is a PMMA whose behaviour depends on its temperature. The computation simulation is based on Navier-Stokes equations where we propose a mixed finite element method with an interpolation P1+/P1 using displacement (or velocity) and pressure as principal variables. The implemented technique uses a mesh composed of triangles (2D) or tetrahedra (3D). The goal of this approach is to model the viscoelastic behaviour of polymers through a fluid-structure coupling technique with a multiphase approach.

Pham, VT.; Silva, L.; Digonnet, H.; Combeaud, C.; Billon, N.; Coupez, T. [Centre for Material Forming (CEMEF), MINES ParisTech, Rue Claude Daunesse, Sophia Antipolis cedex (France)

2011-05-04

318

An epistemology and expectations survey about experimental physics: Development and initial results  

E-print Network

In response to national calls to better align physics laboratory courses with the way physicists engage in research, we have developed an epistemology and expectations survey to assess how students perceive the nature of physics experiments in the contexts of laboratory courses and the professional research laboratory. The Colorado Learning Attitudes about Science Survey for Experimental Physics (E-CLASS) evaluates students' shifts in epistemology and affect at the beginning and end of a semester. Also, at the end of the semester, the E-CLASS assesses students' reflections on their course's expectations for earning a good grade. By basing survey statements on widely embraced learning goals and common critiques of teaching labs, the E-CLASS serves as an assessment tool for lab courses across the undergraduate curriculum and as a tool for PER research. We present the development, evidence of validation, and initial formative assessment results from a sample that includes 45 classes at 20 institutions. We also d...

Zwickl, Benjamin M; Finkelstein, Noah; Lewandowski, H J

2013-01-01

319

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

NASA Technical Reports Server (NTRS)

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

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

1992-01-01

320

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

PubMed

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

2012-03-01

321

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

322

Laser chemical vapor deposition of TiN dots: A comparison of theoretical and experimental results  

NASA Astrophysics Data System (ADS)

A mathematical model for the concentration profile of TiCl4 at the top surface of an Incoloy 800H substrate placed inside a laser chemical vapor deposition (LCVD) reactor is developed by using the three-dimensional transient mass diffusion equation. The model is used for studying the spatial variation of the thickness of TiN dots deposited by LCVD, using a CO2 laser and a reactive atmosphere consisting of TiCl4, N2, and H2. By assuming that the chemical reaction is first-order with respect to TiCl4, and that the sticking coefficient of TiN at the substrate surface is temperature dependent, the deposited TiN film is found to have a volcanic profile under certain conditions, which is in good agreement with experimental results.

Conde, O.; Kar, A.; Mazumder, J.

1992-07-01

323

Inlet Flow Test Calibration for a Small Axial Compressor Facility. Part 1: Design and Experimental Results  

NASA Technical Reports Server (NTRS)

An axial compressor test rig has been designed for the operation of small turbomachines. The inlet region consisted of a long flowpath region with two series of support struts and a flapped inlet guide vane. A flow test was run to calibrate and determine the source and magnitudes of the loss mechanisms in the inlet for a highly loaded two-stage axial compressor test. Several flow conditions and IGV angle settings were established in which detailed surveys were completed. Boundary layer bleed was also provided along the casing of the inlet behind the support struts and ahead of the IGV. A detailed discussion of the flowpath design along with a summary of the experimental results are provided in Part 1.

Miller, D. P.; Prahst, P. S.

1994-01-01

324

NACA0012 benchmark model experimental flutter results with unsteady pressure distributions  

NASA Technical Reports Server (NTRS)

The Structural Dynamics Division at NASA Langley Research Center has started a wind tunnel activity referred to as the Benchmark Models Program. The primary objective of this program is to acquire measured dynamic instability and corresponding pressure data that will be useful for developing and evaluating aeroelastic type computational fluid dynamics codes currently in use or under development. The program is a multi-year activity that will involve testing of several different models to investigate various aeroelastic phenomena. This paper describes results obtained from a second wind tunnel test of the first model in the Benchmark Models Program. This first model consisted of a rigid semispan wing having a rectangular planform and a NACA 0012 airfoil shape which was mounted on a flexible two degree of freedom mount system. Experimental flutter boundaries and corresponding unsteady pressure distribution data acquired over two model chords located at the 60 and 95 percent span stations are presented.

Rivera, Jose A., Jr.; Dansberry, Bryan E.; Bennett, Robert M.; Durham, Michael H.; Silva, Walter A.

1992-01-01

325

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

NASA Astrophysics Data System (ADS)

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

Cheng, Bo; Deng, Xinyan

2009-11-01

326

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

327

Noise characteristics of upper surface blown configurations. Experimental program and results  

NASA Technical Reports Server (NTRS)

An experimental data base was developed from the model upper surface blowing (USB) propulsive lift system hardware. While the emphasis was on far field noise data, a considerable amount of relevant flow field data were also obtained. The data were derived from experiments in four different facilities resulting in: (1) small scale static flow field data; (2) small scale static noise data; (3) small scale simulated forward speed noise and load data; and (4) limited larger-scale static noise flow field and load data. All of the small scale tests used the same USB flap parts. Operational and geometrical variables covered in the test program included jet velocity, nozzle shape, nozzle area, nozzle impingement angle, nozzle vertical and horizontal location, flap length, flap deflection angle, and flap radius of curvature.

Brown, W. H.; Searle, N.; Blakney, D. F.; Pennock, A. P.; Gibson, J. S.

1977-01-01

328

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

329

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

330

Preliminary Test Results of Heshe Hydrogeological Experimental Well Station in Taiwan  

NASA Astrophysics Data System (ADS)

Safe disposal of radioactive waste is a critical issue for the development of nuclear energy. The design of final disposal system is based on the concept of multiple barriers which integrate the natural barriers and engineering barriers for long-term isolation of radioactive wastes. As groundwater is the major medium that can transport radionuclides to our living environment, it is essential to characterize groundwater flow at the disposal site. Taiwan is located at the boundary between the Eurasian plate and the Philippine Sea plate. Geologic formations are often fractured due to tectonic compression and extension. In this study, a well station for the research and development of hydrogeological techniques was established at the Experimental Forest of the National Taiwan University in central Taiwan. There are 10 testing wells, ranging in depth from 25 m to 100 m, at the station. The bedrock beneath the regolith is highly fractured mudstone. As fracture is the preferential pathway of the groundwater flow, the focus of in-situ tests is to investigate the location of permeable fractures and the connection of permeable fractures. Several field tests have been conducted, including geophysical logging, heat-pulse flowmeter, hydraulic test, tracer test and double packer test, for the development of advanced technologies to detect the preferential groundwater flow in fractured rocks.

Chuang, P.; Liu, C.; Lin, M.; Chan, W.; Lee, T.; Chia, Y.; Teng, M.; Liu, C.

2013-12-01

331

Flight Test Results of a Thermoelectric Energy Harvester for Aircraft  

NASA Astrophysics Data System (ADS)

The idea of thermoelectric energy harvesting for low-power wireless sensor systems in aircraft and its practical implementation was recently published. The concept of using a thermoelectric generator (TEG) attached to the aircraft inner hull and a thermal storage device to create an artificial temperature gradient at the TEG during take-off and landing from the temperature changes of the fuselage has passed initial tests and is now subject to flight testing. This work presents preflight test results, e.g., vibration and temperature testing of the harvesters, the practical installation of two harvesting devices inside a test plane, and the first test flight results. Several flight cycles with different flight profiles, flight lengths, and outside temperatures have been performed. Although the influence of different flight profiles on the energy output of the harvester can be clearly observed, the results are in good agreement with expectations from numerical simulations with boundary conditions evaluated from initial climate chamber experiments. In addition, the flight test demonstrates that reliable operation of thermoelectric energy harvesting in harsh aircraft environments seems to be feasible, therefore paving the way for realization of energy-autonomous, wireless sensor networks.

Samson, D.; Kluge, M.; Fuss, T.; Schmid, U.; Becker, Th.

2012-06-01

332

An experimental study of SO3 dissociation as a mechanism for converting and transporting solar energy  

NASA Technical Reports Server (NTRS)

The high temperature catalytic dissocation of SO3 is an important chemical process being considered in the development and application of solar-thermal energy conversion, transport, and storage systems. A facility for evaluating chemical converter-heat exchangers at temperatures to 1000 C with high flow rates of gaseous SO3 feedstock has been assembled and operated on the NMSU campus. Several quartz and metal reactors containing different catalyst configurations have been tested. Descriptions of the test facility and of the reactors are given along with a presentation and discussion of experimental results.

Mccrary, J. H.; Mccrary, G. E.; Chubb, T. A.; Won, Y. S.

1981-01-01

333

Experimental demonstration of high two-photon time-energy entanglement  

SciTech Connect

We report on the experimental demonstration of high energy-time entanglement in two-photon states created in the process of spontaneous parametric down-conversion. We show that the classical variance product, which we violate by three orders of magnitude, actually represents a lower bound estimate of the number of information eigenmodes K. Explicit measurements estimate K to be greater than 100, with theoretical estimates predicting a value of as high as 1x10{sup 6}. These results provide incentive for the practical feasibility of large bandwidth quantum information processing, particularly in cryptography over large distances.

Ali Khan, Irfan; Howell, John C. [Department of Physics and Astronomy, University of Rochester, Rochester, New York 14627 (United States)

2006-03-15

334

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

335

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

336

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

337

Large Fluorescence Enhancements of Fluorophore Ensembles with Multilayer Plasmonic Substrates: Comparison of Theory and Experimental Results.  

PubMed

Multilayer substrates consisting of a glass slide, silver mirror, silica layer, and silver nanoparticles were fabricated using magnetron sputtering. This new geometry of substrates with backplane mirror and dielectric photonic cavity produced large average fluorescence enhancements up to 190-fold. Fluorescence enhancements of five fluorescent probes were measured over the broad spectral range from 470 to 800 nm. Fluorescent probes were streptavidin conjugates attached to the substrate surface through a layer of biotinylated bovine serum albumin. The protein layers represent a common surface modification for surface-based bioassays such as immunoassays or molecular diagnostic assays. We found that optimal enhancement is dependent on the thickness of the dielectric layer separating the silver mirror and the silver nanoparticles and on the spectral range. We performed numerical calculations for enhancement in both the excitation and emission using finite element method (FEM) the results of which were in qualitative agreement with the experimental results. The described method for fabrication multilayered substrates and the results obtained with protein layers demonstrate great potential for the design of simple and ultrasensitive fluorometric bioassays with large optical amplifications compared to the standard approaches of enzyme-based bioassays with dielectric surfaces. PMID:24163712

Szmacinski, Henryk; Badugu, Ramachandram; Mahdavi, Farhad; Blair, Steve; Lakowicz, Joseph R

2012-10-11

338

An experimental investigation of multi-element airfoil ice accretion and resulting performance degradation  

NASA Technical Reports Server (NTRS)

An investigation of the ice accretion pattern and performance characteristics of a multi-element airfoil was undertaken in the NASA Lewis 6- by 9-Foot Icing Research Tunnel. Several configurations of main airfoil, slat, and flaps were employed to examine the effects of ice accretion and provide further experimental information for code validation purposes. The text matrix consisted of glaze, rime, and mixed icing conditions. Airflow and icing cloud conditions were set to correspond to those typical of the operating environment anticipated tor a commercial transport vehicle. Results obtained included ice profile tracings, photographs of the ice accretions, and force balance measurements obtained both during the accretion process and in a post-accretion evaluation over a range of angles of attack. The tracings and photographs indicated significant accretions on the slat leading edge, in gaps between slat or flaps and the main wing, on the flap leading-edge surfaces, and on flap lower surfaces. Force measurments indicate the possibility of severe performance degradation, especially near C sub Lmax, for both light and heavy ice accretion and performance analysis codes presently in use. The LEWICE code was used to evaluate the ice accretion shape developed during one of the rime ice tests. The actual ice shape was then evaluated, using a Navier-Strokes code, for changes in performance characteristics. These predicted results were compared to the measured results and indicate very good agreement.

Potapczuk, Mark G.; Berkowitz, Brian M.

1989-01-01

339

Comparison Between Numerical and Experimental Results on Mechanical Stirrer and Bubbling in a Cylindrical Tank - 13047  

SciTech Connect

The process of vitrification in a cold crucible heated by direct induction is used in the fusion of oxides. Its feature is the production of high-purity materials. The high-level of purity of the molten is achieved because this melting technique excludes the contamination of the charge by the crucible. The aim of the present paper is to analyze the hydrodynamic of the vitrification process by direct induction, with the focus in the effects associated with the interaction between the mechanical stirrer and bubbling. Considering the complexity of the analyzed system and the goal of the present work, we simplified the system by not taking into account the thermal and electromagnetic phenomena. Based in the concept of hydraulic similitude, we performed an experimental study and a numerical modeling of the simplified model. The results of these two studies were compared and showed a good agreement. The results presented in this paper in conjunction with the previous work contribute to a better understanding of the hydrodynamics effects resulting from the interaction between the mechanical stirrer and air bubbling in the cold crucible heated by direct induction. Further works will take into account thermal and electromagnetic phenomena in the presence of mechanical stirrer and air bubbling. (authors)

Lima da Silva, M.; Sauvage, E.; Brun, P. [CEA-Marcoule, BP 17171, 30207 Bagnols sur Ceze (France)] [CEA-Marcoule, BP 17171, 30207 Bagnols sur Ceze (France); Gagnoud, A.; Fautrelle, Y. [SIMaP, Grenoble INP, UJF, CNRS, BP 75, 38402 Saint Martin D'Heres (France)] [SIMaP, Grenoble INP, UJF, CNRS, BP 75, 38402 Saint Martin D'Heres (France); Riva, R. [CEA-Grenoble, 17 rue des Martyrs, 38054 Grenoble (France)] [CEA-Grenoble, 17 rue des Martyrs, 38054 Grenoble (France)

2013-07-01

340

Theoretical modeling and experimental realization of dynamically magnified thermoacoustic-piezoelectric energy harvesters  

NASA Astrophysics Data System (ADS)

Conventional thermoacoustic-piezoelectric (TAP) harvesters convert thermal energy, such as solar or waste heat energy, directly into electrical energy without the need for any moving components. The input thermal energy generates a steep temperature gradient along a porous medium. At a critical threshold of the temperature gradient, self-sustained acoustic waves are developed inside an acoustic resonator. The associated pressure fluctuations impinge on a piezoelectric diaphragm, placed at the end of the resonator. In this study, the TAP harvester is coupled with an auxiliary elastic structure in the form of a simple spring-mass system to amplify the strain experienced by the piezoelectric element. The auxiliary structure is referred to as a dynamic magnifier and has been shown in different areas to significantly amplify the deflection of vibrating structures. A comprehensive model of the dynamically magnified thermoacoustic-piezoelectric (DMTAP) harvester has been developed that includes equations of motions of the system's mechanical components, the harvested voltage, the mechanical impedance of the coupled structure at the resonator end and the equations necessary to compute the self-excited frequencies of oscillations inside the acoustic resonator. Theoretical results confirmed that significant amplification of the harvested power is feasible if the magnifier's parameters are properly chosen. The performance characteristics of experimental prototypes of a thermoacoustic-piezoelectric resonator with and without the magnifier are examined. The obtained experimental findings are validated against the theoretical results. Dynamic magnifiers serve as a novel approach to enhance the effectiveness of thermoacoustic energy harvested from waste heat by increasing the efficiency of their harvesting components.

Nouh, M.; Aldraihem, O.; Baz, A.

2014-07-01

341

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

342

Assessing Internet energy intensity: A review of methods and results  

SciTech Connect

Assessing the average energy intensity of Internet transmissions is a complex task that has been a controversial subject of discussion. Estimates published over the last decade diverge by up to four orders of magnitude — from 0.0064 kilowatt-hours per gigabyte (kWh/GB) to 136 kWh/GB. This article presents a review of the methodological approaches used so far in such assessments: i) top–down analyses based on estimates of the overall Internet energy consumption and the overall Internet traffic, whereby average energy intensity is calculated by dividing energy by traffic for a given period of time, ii) model-based approaches that model all components needed to sustain an amount of Internet traffic, and iii) bottom–up approaches based on case studies and generalization of the results. Our analysis of the existing studies shows that the large spread of results is mainly caused by two factors: a) the year of reference of the analysis, which has significant influence due to efficiency gains in electronic equipment, and b) whether end devices such as personal computers or servers are included within the system boundary or not. For an overall assessment of the energy needed to perform a specific task involving the Internet, it is necessary to account for the types of end devices needed for the task, while the energy needed for data transmission can be added based on a generic estimate of Internet energy intensity for a given year. Separating the Internet as a data transmission system from the end devices leads to more accurate models and to results that are more informative for decision makers, because end devices and the networking equipment of the Internet usually belong to different spheres of control. -- Highlights: • Assessments of the energy intensity of the Internet differ by a factor of 20,000. • We review top–down, model-based, and bottom–up estimates from literature. • Main divergence factors are the year studied and the inclusion of end devices. • We argue against extending the Internet system boundary beyond data transmission. • Decision-makers need data that differentiates between end devices and transmission.

Coroama, Vlad C., E-mail: vcoroama@gmail.com [Instituto Superior Técnico, Universidade Técnica de Lisboa, Av. Rovisco Pais 1, 1049-001 Lisboa (Portugal); Hilty, Lorenz M. [Department of Informatics, University of Zurich, Binzmühlestrasse 14, 8050 Zurich (Switzerland) [Department of Informatics, University of Zurich, Binzmühlestrasse 14, 8050 Zurich (Switzerland); Empa, Swiss Federal Laboratories for Materials Science and Technology, Lerchenfeldstr. 5, 9014 St. Gallen (Switzerland); Centre for Sustainable Communications, KTH Royal Institute of Technology, Lindstedtsvägen 5, 100 44 Stockholm (Sweden)

2014-02-15

343

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

PubMed Central

Micro-focusing optical devices at synchrotron beamlines usually have a limited acceptance, but more flux can be intercepted if such optics are used to focus secondary sources created by the primary optics. Flux throughput can be maximized by placing the secondary focusing optics close to or exactly at the secondary source position. However, standard methods of beamline optics analysis, such as the lens equation or matching the mirror surface to an ellipse, work poorly when the source-to-optics distance is very short. In this paper the general characteristics of the focusing of beams with Gaussian profiles by a ‘thin lens’ are analysed under the paraxial approximation in phase space, concluding that the focusing of a beam with a short source-to-optics distance is distinct from imaging the source; slope errors are successfully included in all the formulas so that they can be used to calculate beamline focusing with good accuracy. A method is also introduced to use the thin-lens result to analyse the micro-focusing produced by an elliptically bent trapezoid-shaped Kirkpatrick–Baez mirror. The results of this analysis are in good agreement with ray-tracing simulations and are confirmed by the experimental results of the secondary focusing at the 18-ID Bio-CAT beamline (at the APS). The result of secondary focusing carried out at 18-ID using a single-bounce capillary can also be explained using this phase-space analysis. A discussion of the secondary focusing results is presented at the end of this paper. PMID:20724786

Huang, Rong; Meron, Mati; Kujala, Naresh; Barrea, Raul A.

2010-01-01

344

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

SciTech Connect

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

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

2011-11-17

345

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

346

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

347

Experimental analysis of fluid mechanical energy losses in aortic valve stenosis: importance of pressure recovery.  

PubMed

Current methods for assessing the severity of aortic stenosis depend primarily on measures of maximum systolic pressure drop at the aortic valve orifice and related calculations such as valve area. It is becoming increasingly obvious, however, that the impact of the obstruction on the left ventricle is equally important in assessing its severity and could potentially be influenced by geometric factors of the valve, causing variable degrees of downstream pressure recovery. The goal of this study was to develop a method for measuring fluid mechanical energy losses in aortic stenosis that could then be directly related to the hemodynamic load placed on the left ventricle. A control volume form of conservation of energy was theoretically analyzed and modified for application to aortic valve stenosis measurements. In vitro physiological pulsatile flow experiments were conducted with different types of aortic stenosis models, including a venturi meter, a nozzle, and 21-mm Medtronic-Hall tilting disc and St. Jude bileaflet mechanical valves. The energy loss created by each model was measured for a wide range of experimental conditions, simulating physiological variation. In all cases, there was more energy lost for the nozzle (mean = 0.27 J) than for any other model for a given stroke volume. The two prosthetic valves generated approximately the same energy losses (mean = 0.18 J), which were not statistically different, whereas the venturi meter had the lowest energy loss for all conditions (mean = 0.037 J). Energy loss correlated poorly with orifice pressure drop (r2 = 0.34) but correlated well with recovered pressure drop (r2 = 0.94). However, when the valves were considered separately, orifice and recovered pressure drop were both strongly correlated with energy loss (r2 = 0.99, 0.96). The results show that recovered pressure drop, not orifice pressure drop, is directly related to the energy loss that determines pump work and therefore is a more accurate measure of the hemodynamic significance of aortic stenosis. PMID:8923988

Heinrich, R S; Fontaine, A A; Grimes, R Y; Sidhaye, A; Yang, S; Moore, K E; Levine, R A; Yoganathan, A P

1996-01-01

348

Save Energy Now Assessments Results 2008 Detailed Report  

SciTech Connect

In October 2005, U.S. Department of Energy Secretary Bodman launched his Easy Ways to Save Energy campaign with a promise to provide energy assessments to 200 of the largest U.S. manufacturing plants. DOE's Industrial Technologies Program (ITP) responded to the Secretary's campaign with its Save Energy Now initiative, featuring a new and highly cost-effective form of energy savings assessment. The approach for these assessments drew heavily on the existing resources of ITP's technology delivery component. Over the years, ITP Technology Delivery has worked with industry partners to assemble a suite of respected software tools, proven assessment protocols, training curricula, certified energy experts, and strong partnerships for deployment. The Save Energy Now assessments conducted in calendar year 2006 focused on natural gas savings and targeted many of the nation's largest manufacturing plants - those that consume at least 1 TBtu of energy annually. The 2006 Save Energy Now assessments focused primarily on assessments of steam and process heating systems, which account for an estimated 74% of all natural gas use by U.S. manufacturing plants. Because of the success of the Save Energy Now assessments conducted in 2006 and 2007, the program was expanded and enhanced in two major ways in 2008: (1) a new goal was set to perform at least 260 assessments; and (2) the assessment focus was expanded to include pumping, compressed air, and fan systems in addition to steam and process heating. DOE ITP also has developed software tools to assess energy efficiency improvement opportunities in pumping, compressed air, and fan systems. The Save Energy Now assessments integrate a strong training component designed to teach industrial plant personnel how to use DOE's opportunity assessment software tools. This approach has the advantages of promoting strong buy-in of plant personnel for the assessment and its outcomes and preparing them better to independently replicate the assessment process at the company's other facilities. Another important element of the Save Energy Now assessment process is the follow-up process used to identify how many of the recommended savings opportunities from individual assessments have been implemented in the industrial plants. Plant personnel involved with the Save Energy Now assessments are contacted 6 months, 12 months, and 24 months after individual assessments are completed to determine implementation results. A total of 260 Save Energy Now assessments were successfully completed in calendar year 2008. This means that a total of 718 assessments were completed in 2006, 2007, and 2008. As of July 2009, we have received a total of 239 summary reports from the ESAs that were conducted in year 2008. Hence, at the time that this report was prepared, 680 final assessment reports were completed (200 from year 2006, 241 from year 2007, and 239 from year 2008). The total identified potential cost savings from these 680 assessments is $1.1 billion per year, including natural gas savings of about 98 TBtu per year. These results, if fully implemented, could reduce CO{sub 2} emissions by about 8.9 million metric tons annually. When this report was prepared, data on implementation of recommended energy and cost savings measures from 488 Save Energy Now assessments were available. For these 488 plants, measures saving a total of $147 million per year have been implemented, measures that will save $169 million per year are in the process of being implemented, and plants are planning implementation of measures that will save another $239 million per year. The implemented recommendations are already achieving total CO{sub 2} reductions of about 1.8 million metric tons per year. This report provides a summary of the key results for the Save Energy Now assessments completed in 2008; details of the 6-month, 12-month, and 24-month implementation results obtained to date; and an evaluation of these implementation results. This report also summarizes key accomplishments, findings, and lessons learned from all the Save Energy No

Wright, Anthony L [ORNL; Martin, Michaela A [ORNL; Nimbalkar, Sachin U [ORNL; Quinn, James [U.S. Department of Energy; Glatt, Ms. Sandy [DOE Industrial Technologies Program; Orthwein, Mr. Bill [U.S. Department of Energy

2010-09-01

349

Save Energy Now Assessments Results 2008 Summary Report  

SciTech Connect

In October 2005, U.S. Department of Energy Secretary Bodman launched his Easy Ways to Save Energy campaign with a promise to provide energy assessments to 200 of the largest U.S. manufacturing plants. DOE's Industrial Technologies Program (ITP) responded to the Secretary's campaign with its Save Energy Now initiative, featuring a new and highly cost-effective form of energy savings assessment. The approach for these assessments drew heavily on the existing resources of ITP's technology delivery component. Over the years, ITP Technology Delivery has worked with industry partners to assemble a suite of respected software tools, proven assessment protocols, training curricula, certified energy experts, and strong partnerships for deployment. The Save Energy Now assessments conducted in calendar year 2006 focused on natural gas savings and targeted many of the nation's largest manufacturing plants - those that consume at least 1 TBtu of energy annually. The 2006 Save Energy Now assessments focused primarily on assessments of steam and process heating systems, which account for an estimated 74% of all natural gas use by U.S. manufacturing plants. Because of the success of the Save Energy Now assessments conducted in 2006 and 2007, the program was expanded and enhanced in two major ways in 2008: (1) a new goal was set to perform at least 260 assessments; and (2) the assessment focus was expanded to include pumping, compressed air, and fan systems in addition to steam and process heating. DOE ITP also has developed software tools to assess energy efficiency improvement opportunities in pumping, compressed air, and fan systems. The Save Energy Now assessments integrate a strong training component designed to teach industrial plant personnel how to use DOE's opportunity assessment software tools. This approach has the advantages of promoting strong buy-in of plant personnel for the assessment and its outcomes and preparing them better to independently replicate the assessment process at the company's other facilities. Another important element of the Save Energy Now assessment process is the follow-up process used to identify how many of the recommended savings opportunities from individual assessments have been implemented in the industrial plants. Plant personnel involved with the Save Energy Now assessments are contacted 6 months, 12 months, and 24 months after individual assessments are completed to determine implementation results. A total of 260 Save Energy Now assessments were successfully completed in calendar year 2008. This means that a total of 718 assessments were completed in 2006, 2007, and 2008. As of July 2009, we have received a total of 239 summary reports from the ESAs that were conducted in year 2008. Hence, at the time that this report was prepared, 680 final assessment reports were completed (200 from year 2006, 241 from year 2007, and 239 from year 2008). The total identified potential cost savings from these 680 assessments is $1.1 billion per year, including natural gas savings of about 98 TBtu per year. These results, if fully implemented, could reduce CO{sub 2} emissions by about 8.9 million metric tons annually. When this report was prepared, data on implementation of recommended energy and cost savings measures from 488 Save Energy Now assessments were available. For these 488 plants, measures saving a total of $147 million per year have been implemented, measures that will save $169 million per year are in the process of being implemented, and plants are planning implementation of measures that will save another $239 million per year. The implemented recommendations are already achieving total CO{sub 2} reductions of about 1.8 million metric tons per year. This report provides a summary of the key results for the Save Energy Now assessments completed in 2008; details of the 6-month, 12-month, and 24-month implementation results obtained to date; and an evaluation of these implementation results. This report also summarizes key accomplishments, findings, and lessons learned from all the Save Energy No

Wright, Anthony L [ORNL; Martin, Michaela A [ORNL; Nimbalkar, Sachin U [ORNL; Quinn, James [U.S. Department of Energy; Glatt, Ms. Sandy [DOE Industrial Technologies Program; Orthwein, Mr. Bill [U.S. Department of Energy

2010-09-01

350

Recent Experimental Results from the NSCL on the Structure of Exotic Nuclei  

SciTech Connect

The Coupled Cyclotron Facility at the National Superconducting Cyclotron Laboratory at Michigan State University provides a large variety of new isotopes previously inaccessible and others at rates sufficient for in-beam spectroscopy. This talk presents some of our recent results elucidating the structure of exotic nuclei.After a general overview of scientific highlights from the first two years of operation particular results from several in-beam gamma-ray spectroscopy experiments in the vicinities of neutron numbers N=16, N=20, N=28 in the {pi}(sd) shell around 56Ni will be discussed. Inelastic scattering experiments with gamma-ray detection on light and heavy targets have determined specific transition matrix elements and excited state energies. One- and two-particle nucleon knockout reactions were used to investigate the wave functions of specific states and to deduce corresponding spectroscopic factors.

Glasmacher, T.; Campbell, C.M.; Church, J.A.; Dinca, D.C.; Gade, A.; Olliver, H.; Sherrill, B.M.; Yurkewicz, K.L. [National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, MI 48824 (United States); Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824 (United States); Bazin, D.; Mueller, W.F. [National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, MI 48824 (United States)

2004-02-27

351

Dynamics of dual prism adaptation: relating novel experimental results to a minimalistic neural model.  

PubMed

In everyday life, humans interact with a dynamic environment often requiring rapid adaptation of visual perception and motor control. In particular, new visuo-motor 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 ('dual-adaptation'). 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 dual-adaptation be faster if switches ('phase changes') between the environments occur more frequently? We investigated the dynamics of dual-adaptation under different training schedules in a virtual pointing experiment. Surprisingly, we found that acquisition speed of dual visuo-motor 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 dual-adaptation 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 dual-adaptation 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

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

2013-01-01

352

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

353

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 visuo–motor 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 (‘dual–adaptation’). 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 dual–adaptation be faster if switches (‘phase changes’) between the environments occur more frequently? We investigated the dynamics of dual–adaptation under different training schedules in a virtual pointing experiment. Surprisingly, we found that acquisition speed of dual visuo–motor 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 dual–adaptation 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 dual–adaptation 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

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

2013-01-01

354

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

355

Spacecraft Power Beaming Using High-Energy Lasers, Experimental Validation  

Microsoft Academic Search

The lifetime of many spacecrafts are often limited by degradation of their electrical power subsystem, e.g. radiation-damaged solar arrays or failed batteries. Being able to beam power from terrestrial sites using high energy lasers, could alleviate this limitation, extending the lifetime of billions of dollars of satellite assets, as well as providing additional energy for electric propulsion that can be

Sherif Michael; Sherif

2008-01-01

356

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

PubMed Central

Significant improvements have made it possible to add the technology of time-of-flight (TOF) to improve PET imaging, particularly for oncology applications. The goals of this work were to investigate the benefits of TOF in experimental phantoms and to determine how these benefits translate into improved performance for patient imaging. Methods The Gemini TF scanner (Philips Medical Systems) used in this study is a fully 3D scanner and utilizes the scintillator LYSO with a system timing resolution of ~600 ps. The data are acquired in list-mode and reconstructed with an ML-EM algorithm; the system model includes the TOF kernel and corrections for attenuation, detector normalization, randoms, and scatter. The scatter correction is an extension of the modelbased single-scatter simulation to include the time domain. Phantom measurements to study the benefit of TOF include 27-cm and 35-cm diameter distributions with spheres ranging in size from 10 mm to 37 mm. To assess the benefit of TOF PET for clinical imaging, patient studies are quantitatively analyzed. Results The lesion phantom studies demonstrate the improved contrast of the smallest spheres with TOF compared to non-TOF and also confirm the faster convergence of contrast with TOF. These gains are evident from visual inspection of the images, as well as a quantitative evaluation of contrast recovery of the spheres and noise in the background. The gains with TOF are higher for larger objects. These results correlate with patient studies in which lesions are seen more clearly and with higher uptake at comparable noise for TOF than with non-TOF. Conclusion TOF leads to a better contrast vs. noise trade-off than non-TOF but one that is difficult to quantify in terms of a simple sensitivity gain improvement: a single gain factor for TOF improvement does not include the increased rate of convergence with TOF, nor does it consider that TOF may converge to a different contrast than non-TOF. The experimental phantoms results agree with those of prior simulations and help explain the improved image quality with TOF for patient oncology studies. PMID:18287269

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

2009-01-01

357

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 Šumbera for the STAR Collboration

2013-12-10

358

Characterization of melting and solidification in a real-scale PCM–air heat exchanger: Experimental results and empirical model  

Microsoft Academic Search

This paper describes the experimental studies carried out to test thermal cycling of a real-scale PCM–air heat exchanger at ambient temperatures. To achieve this goal an experimental setup previously designed and used for testing real-scale prototypes of PCM–air heat exchangers is modified. The PCM used is commercially available, organic, and paraffin based. The total energy exchanged during melting and solidification,

Pablo Dolado; Ana Lazaro; Jose M. Marin; Belen Zalba

2011-01-01

359

Experimental energy loss of slow H{sup +} and H{sub 2}{sup +} in channeling conditions  

SciTech Connect

The interactions of hydrogen molecular ions (H{sub 2}{sup +}) and protons in the low energy range (E<7.5 keV/u) with very thin foils of monocrystalline gold are experimentally studied. Measurements of energy loss distributions of molecular fragments, recombined molecules, and protons channeled in the <100> direction of a monocrystalline gold thin film have been performed. From the energy loss data we determine the stopping power ratio, which shows a significant negative ''vicinage effect,'' giving a reduced energy loss of molecular fragments and recombined molecules as compared to the energy loss of protons. This effect is more pronounced in the case of detected molecules. Computational simulations, where nonlinear models are included, qualitatively agree with our experimental results and suggest that some pairs of ions travel and emerge from the crystal with appropriate internuclear distances and relative velocities and are able to recombine at the exit.

Valdes, J.E.; Parra, C.; Diaz-Valdes, J.; Denton, C.D.; Agurto, C.; Ortega, F.; Arista, N.R.; Vargas, P. [Laboratorio de Colisiones Atomicas, Departamento de Fisica, Universidad de Santiago de Chile, Casilla 307, Santiago (Chile); Departamento de Fisica, Universidad Federico Santa Maria, Casilla 110-V, Valparaiso (Chile); Departamento de Fisica, Universidad de Concepcion, Casilla 160-C, Correo 3, Concepcion (Chile); Departamento de Fisica, Universidad Federico Santa Maria, Casilla 110-V, Valparaiso (Chile); Laboratorio de Colisiones Atomicas, Departamento de Fisica, Universidad de Santiago de Chile, Casilla 307, Santiago (Chile); Division Colisiones Atomicas, Centro Atomico Bariloche, Instituto Balseiro, S.C. de Bariloche (Argentina); Departamento de Fisica, Universidad Federico Santa Maria, Casilla 110-V, Valparaiso (Chile)

2003-12-01

360

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

361

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

PubMed

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, T(1)s, equilibrium magnetizations, M(0)s, 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 T(1); (iii) T(1) and M(0) changes between control and intervention periods, and chemical exchange contribute to different extents to quantitation errors in phosphocreatine and gamma-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. PMID:12713964

Galbán, Craig J; Ellis, Scott J; Spencer, Richard G S

2003-04-01

362

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.

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

2003-04-01

363

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

NASA Technical Reports Server (NTRS)

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

Plumb, Robert C.

1992-01-01

364

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

PubMed

Ethicists contend that researchers are obliged to report genetic research findings to individual study participants when they are clinically significant, that is, when they are clinically useful or personally meaningful to participants. Yet whether such standards are well understood and can be consistently applied remains unknown. We conducted an international, cross-sectional survey of cystic fibrosis (CF) and autism genetics researchers using a quasi-experimental design to explore factors influencing researchers' judgments. Eighty percent of researchers agreed, in principle, that clinically significant findings should be reported to individual participants. Yet judgments about when a specific finding was considered clinically significant or warranted reporting varied by scientific factors (replication, robustness, intentionality, and disease context), capacity of the research team to explain the results, and type of research ethics guidance. Further, judgments were influenced by the researchers' disease community (autism or CF), their primary role (clinical, molecular, statistical) and their beliefs regarding a general reporting obligation. In sum, judgments about the clinical significance of genetic research results, and about whether they should be reported, are influenced by scientific parameters as well as contextual factors related to the specific research project and the individual researcher. These findings call into question the assumption that the conditions under which an obligation to disclose arises are uniformly understood and actionable. Adjudicating the clinical readiness of provisional data may be a responsibility better suited to evaluative experts at arms' length of the provisional data in question, rather than a responsibility imposed upon researchers themselves. PMID:21407262

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

2011-07-01

365

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

366

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

367

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

NASA Astrophysics Data System (ADS)

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?1011 photons/s at 125 eV and 2?1010 photons/s at about 1100 eV. Using the high flux grating with the best resolution achievable 1.7?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 ?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.; Finazzi, M.; Pardini, T.; Platè, M.; Rochow, R.; Cocco, D.; Parmigiani, F.

2004-05-01

368

Experimental Test of Bose-Einstein Condensation Mechanism for Low Energy Nuclear Reaction in Nanoscale Atomic Clusters  

Microsoft Academic Search

We report preliminary results of experimental test of the Bose-Einstein condensation (BEC) mechanism for ultra low energy nuclear fusion in nano-scale atomic clusters at pressures up to a 20,000 psi and at both room temperature and liquid nitrogen temperatures. BEC of integer-spin nuclei was suggested as a possible mechanism for ultra low-energy nuclear reaction in 1998. Recently, theoretical studies of

Yeong E. Kim; David S. Koltick; Ryan Prenger; Jeff Myers; Rhoda Koltick

2005-01-01

369

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

370

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

371

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

372

The roughness of the protein energy landscape results in anomalous diffusion of the polypeptide backbone.  

PubMed

Although protein folding is often described by motion on a funnel-shaped overall topology of the energy landscape, the many local interactions that can occur result in considerable landscape roughness which slows folding by increasing internal friction. Recent experimental results have brought to light that this roughness also causes unusual diffusional behaviour of the backbone of an unfolded protein, i.e. the relative motion of protein sections cannot be described by the normal diffusion equation, but shows strongly subdiffusional behaviour with a nonlinear time dependence of the mean square displacement, ?r(2)(t)? ? t(?) (? ? 1). This results in significantly slower configurational equilibration than had been assumed hitherto. Analysis of the results also allows quantification of the energy landscape roughness, i.e. the root-mean-squared depth of local minima, yielding a value of 4-5kBT for a typical small protein. PMID:25412176

Volk, Martin; Milanesi, Lilia; Waltho, Jonathan P; Hunter, Christopher A; Beddard, Godfrey S

2014-12-10

373

Experimental self-energy corrections to the Ni valence band  

Microsoft Academic Search

The self-energy responsible for the narrowing of the Ni 3d band as observed in photoemission data is obtained from a comparison of a calculated band structure with a band structure determined from photoemission data. The self-energy is found to depend on both wavevector k and band index n, but the authors are able to demonstrate that this dependence is almost

H. I. Starnberg; P. O. Nilsson

1988-01-01

374

Experimental Analysis of a Piezoelectric Energy Harvesting System for Harmonic, Random, and Sine on Random Vibration  

SciTech Connect

Formal journal article Experimental analysis of a piezoelectric energy harvesting system for harmonic, random, and sine on random vibration Abstract: Harvesting power with a piezoelectric vibration powered generator using a full-wave rectifier conditioning circuit is experimentally compared for varying sinusoidal, random and sine on random (SOR) input vibration scenarios. Additionally, the implications of source vibration characteristics on harvester design are discussed. Studies in vibration harvesting have yielded numerous alternatives for harvesting electrical energy from vibrations but piezoceramics arose as the most compact, energy dense means of energy transduction. The rise in popularity of harvesting energy from ambient vibrations has made piezoelectric generators commercially available. Much of the available literature focuses on maximizing harvested power through nonlinear processing circuits that require accurate knowledge of generator internal mechanical and electrical characteristics and idealization of the input vibration source, which cannot be assumed in general application. In this manuscript, variations in source vibration and load resistance are explored for a commercially available piezoelectric generator. We characterize the source vibration by its acceleration response for repeatability and transcription to general application. The results agree with numerical and theoretical predictions for in previous literature that load optimal resistance varies with transducer natural frequency and source type, and the findings demonstrate that significant gains are seen with lower tuned transducer natural frequencies for similar source amplitudes. Going beyond idealized steady state sinusoidal and simplified random vibration input, SOR testing allows for more accurate representation of real world ambient vibration. It is shown that characteristic interactions from more complex vibrational sources significantly alter power generation and power processing requirements by increasing harvested power, shifting optimal conditioning impedance, inducing significant voltage supply fluctuations and ultimately rendering idealized sinusoidal and random analyses insufficient.

Cryns, Jackson W.; Hatchell, Brian K.; Santiago-Rojas, Emiliano; Silvers, Kurt L.

2013-07-01

375

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

376

Experimental results of a household automatic icemaker in a refrigerator/freezer  

SciTech Connect

This paper describes the performance test results of an automatic icemaker refrigerator under various modes of icemaker operation. The tests were conducted on a 20-ft{sup 3} (0.566-m{sup 3}) household refrigerator that had a single forced convection evaporator and was charged with R-12. The focus of the research was to ascertain the effect of icemaker operation on the refrigerator`s daily energy consumption. Thus, three different types of tests were conducted, depending upon the icemaker`s operating mode. In the first test type, the baseline, the automatic icemaker was turned off and no ice was made. In the second test type, the ice-making mode (test A), the icemaker was turned on and ice was continuously made. Compared to the baseline, additional power was intermittently consumed by a mold heater that melts the ice cubes` interface with the tray, a solenoid valve that supplies water to the icemaker tray, and a motor that rotates the ejector blades to press the crescent-shaped ice cubes out of the mold and unload them into an ice bin. In the third test type, the failure mode (test B), the water supply was manually disconnected but the icemaker was left turned on. Even though no ice was made, additional power was still consumed by the mold heater, the solenoid valve, and the motorized ejector. In tests A and B, the energy consumed by the icemaker`s components increases the cooling load, which raises the compressor power consumption. The present study shows that at the AHAM-specified test conditions, uninterrupted icemaking increased the daily energy consumption by 22.5% to 27.2%.

Haider, I.; Feng, H.; Radermacher, R. [Univ. of Maryland, College Park, MD (United States). Center for Environmental Energy Engineering

1996-12-31

377

Experimental results and modeling techniques for substrate noise in mixed-signal integrated circuits  

Microsoft Academic Search

An experimental technique is described for observing the effects of switching transients in digital MOS circuits that perturb analog circuits integrated on the same die by means of coupling through the substrate. Various approaches to reducing substrate crosstalk (the use of physical separation of analog and digital circuits, guard rings, and a low-inductance substrate bias) are evaluated experimentally for a

David K. Su; Marc J. Loinaz; Shoichi Masui; Bruce A. Wooley

1993-01-01

378

Preliminary results of the LLNL airborne experimental test-bed SAR system  

Microsoft Academic Search

The Imaging and Detection Program (IDP) within Laser Programs at Lawrence Livermore National Laboratory (LLNL) in cooperation with the Hughes Aircraft Company has developed a versatile, high performance, airborne experimental test-bed (AETB) capability. The test-bed has been developed for a wide range of research and development experimental applications including radar and radiometry plus, with additional aircraft modifications, optical systems. The

M. G. Miller; C. J. Mullenhoff; R. D. Kiefer; J. M. Brase; M. G. Wieting; G. L. Berry; H. E. Jones

1996-01-01

379

Primary experimental results of wire-array Z-pinches on PTS  

NASA Astrophysics Data System (ADS)

The Primary Test Stand (PTS) developed at the China Academy of Engineering Physics is a multiterawatt pulsed power driver, which can deliver a ˜10 MA, 70 ns rise-time (10%-90%) current to a short circuit load and has important applications in Z-pinch driven inertial confinement fusion and high energy density physics. In this paper, primary results of tungsten wire-array Z-pinch experiments on PTS are presented. The load geometries investigated include 15-mm-tall cylindrical single and nested arrays with diameter ranging from 14.4-26.4 mm, and consisting of 132˜276 tungsten wires with 5˜10 ?m in diameter. Multiple diagnostics were fielded to determine the characteristics of x-ray radiations and to obtain self-emitting images of imploding plasmas. X-ray power up to 80 TW with ˜3 ns FWMH is achieved by using nested wire arrays. The total x-ray energy exceeds 500 kJ and the peak radiation temperature is about 150 eV. Typical velocity of imploding plasmas goes around 3˜5×107 cm/s and the radial convergence ratio is between 10 and 20.

Huang, X. B.; Zhou, S. T.; Ren, X. D.; Dan, J. K.; Wang, K. L.; Zhang, S. Q.; Li, J.; Xu, Q.; Cai, H. C.; Duan, S. C.; Ouyang, K.; Chen, G. H.; Ji, C.; Wang, M.; Feng, S. P.; Yang, L. B.; Xie, W. P.; Deng, J. J.

2014-12-01

380

Preliminary Experimental Results of Integrated Gasification Fuel Cell Operation Using Hardware Simulation  

SciTech Connect

A newly developed integrated gasification fuel cell (IGFC) hybrid system concept has been tested using the Hybrid Performance (Hyper) project hardware-based simulation facility at the U.S. Department of Energy, National Energy Technology Laboratory. The cathode-loop hardware facility, previously connected to the real-time fuel cell model, was integrated with a real-time model of a gasifier of solid (biomass and fossil) fuel. The fuel cells are operated at the compressor delivery pressure, and they are fueled by an updraft atmospheric gasifier, through the syngas conditioning train for tar removal and syngas compression. The system was brought to steady state; then several perturbations in open loop (variable speed) and closed loop (constant speed) were performed in order to characterize the IGFC behavior. Coupled experiments and computations have shown the feasibility of relatively fast control of the plant as well as a possible mitigation strategy to reduce the thermal stress on the fuel cells as a consequence of load variation and change in gasifier operating conditions. Results also provided an insight into the different features of variable versus constant speed operation of the gas turbine section.

Traverso, Alberto; Tucker, David; Haynes, Comas L.

2012-07-01

381

Experimental results from a preclinical X-ray phase-contrast CT scanner  

PubMed Central

To explore the future clinical potential of improved soft-tissue visibility with grating-based X-ray phase contrast (PC), we have developed a first preclinical computed tomography (CT) scanner featuring a rotating gantry. The main challenge in the transition from previous bench-top systems to a preclinical scanner are phase artifacts that are caused by minimal changes in the grating alignment during gantry rotation. In this paper, we present the first experimental results from the system together with an adaptive phase recovery method that corrects for these phase artifacts. Using this method, we show that the scanner can recover quantitatively accurate Hounsfield units in attenuation and phase. Moreover, we present a first tomography scan of biological tissue with complementary information in attenuation and phase contrast. The present study hence demonstrates the feasibility of grating-based phase contrast with a rotating gantry for the first time and paves the way for future in vivo studies on small animal disease models (in the mid-term future) and human diagnostics applications (in the long-term future). PMID:23019354

Tapfer, Arne; Bech, Martin; Velroyen, Astrid; Meiser, Jan; Mohr, Jürgen; Walter, Marco; Schulz, Joachim; Pauwels, Bart; Bruyndonckx, Peter; Liu, Xuan; Sasov, Alexander; Pfeiffer, Franz

2012-01-01

382

Preparation, conduct, and experimental results of the AVR loss-of-coolant accident simulation test  

SciTech Connect

A loss-of-coolant accident (LOCA) is one of the most severe accidents for a nuclear power plant. To demonstrate inherent safety characteristics incorporated into small high-temperature gas-cooled reactor (HTGR) design, LOCA simulation tests have been conducted at the Arbeitsgemeinschaft Versuchsreaktor (AVR), the German pebble-bed-high-temperature reactor plant. The AVR is the only nuclear power plant ever to have been intentionally subjected to LOCA conditions without emergency cooling. This paper presents the planning and licensing activities including pretest predictions performed for the LOCA test are described, and the conduct of the test and experimental results. The LOCA test was planned to create conditions that would exist if a rapid LOCA occurred with the reactor operating at full power. The test demonstrated this reactor's safe response to an accident in which the coolant escapes from the reactor core and no emergency system is available to provide coolant flow to the core. The test is of special interest because it demonstrates the inherent safety features incorporated into optimized modular HTGR designs. The main LOCA test lasted for 5 days. After the test began, core temperatures increased for {approx}13 h and then gradually and continually decreased as the rate of heat dissipation from the core exceeded the simulated decay power. Throughout the test, temperatures remained below limiting values for the core and other reactor components.

Kruger, K.; Bergerfurth, A.; Burger, S.; Pohl, P.; Wimmers, M. (Arbeitsgemeinschaft Versuchsreaktor AVR GmbH, Duesseldorf (DE)); Cleveland, J.C. (Oak Ridge National Lab., TN (United States))

1991-02-01

383

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

384

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

385

A new mechanical device for circular compression anastomosis. Preliminary results of animal and clinical experimentation.  

PubMed Central

The authors report the preliminary results obtained in animal and clinical experimentation of a new mechanical device for circular anastomosis which they have developed. It is a gun that places an apparatus consisting of three polypropylene rings that, through the compression among them of the severed edges of the bowel, realize a sutureless anastomosis and are spontaneously evacuated. Fifty-eight colonic anastomoses were performed in dogs with this device; 23 stapled colonic anastomoses were also executed concurrently. Forty-four animals underwent a relaparotomy to remove the colonic specimen containing the anastomoses. Bursting pressure and the histologic features of the anastomoses were evaluated at different time intervals after operation. A good healing of all compression anastomoses was observed, thereby allowing them to initiate the experience in humans. Thirteen anastomoses (6 colorectal extraperitoneal, 1 colorectal intraperitoneal, 5 colocolonic, 1 ileorectal) were performed at the 1st Surgical Department, Milan University. One subclinical leakage (7.7%) spontaneously healed in a few days. No stenoses were observed. Images Fig. 1. Fig. 2., Fig. 4., Fig. 6. Fig. 3., Fig. 5., Fig. 7. Fig. 8. Fig. 9. PMID:3345111

Rosati, R; Rebuffat, C; Pezzuoli, G

1988-01-01

386

Experimental results from a preclinical X-ray phase-contrast CT scanner.  

PubMed

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, Jürgen; Walter, Marco; Schulz, Joachim; Pauwels, Bart; Bruyndonckx, Peter; Liu, Xuan; Sasov, Alexander; Pfeiffer, Franz

2012-09-25

387

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 Alfvén 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 & Török, 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

388

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 find 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, E., E-mail: zarkadoulae@ornl.gov [School of Physics and Astronomy, Queen Mary University of London, Mile End Road, London E1 4NS (United Kingdom); SEPnet, Queen Mary University of London, Mile End Road, London E1 4NS (United Kingdom); Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); Devanathan, R. [Nuclear Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 99352 (United States); Weber, W. J. [Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); Department of Materials Science and Engineering, University of Tennessee, Knoxville, Tennessee 37996 (United States); Seaton, M. A.; Todorov, I. T. [STFC Daresbury Laboratory, Scientific Computing Department, Keckwick Lane, Daresbury, Warrington, Cheshire WA4 4AD (United Kingdom); Nordlund, K. [University of Helsinki, P.O. Box 43, FIN-00014 Helsinki (Finland); Dove, M. T. [School of Physics and Astronomy, Queen Mary University of London, Mile End Road, London E1 4NS (United Kingdom); Trachenko, K. [School of Physics and Astronomy, Queen Mary University of London, Mile End Road, London E1 4NS (United Kingdom); SEPnet, Queen Mary University of London, Mile End Road, London E1 4NS (United Kingdom)

2014-02-28

389

Nitrogen-broadened lineshapes in the oxygen A-band: Experimental results and theoretical calculations  

NASA Astrophysics Data System (ADS)

We report measurements for N 2-broadening, pressure-shift and line mixing coefficients for 55 oxygen transitions in the A-band retrieved using a multispectrum fitting technique. Nineteen laboratory absorption spectra were recorded at 0.02 cm -1 resolution using a multi-pass absorption cell with path length of 1636.9 cm and the IFS 120 Fourier transform spectrometer located at Justus-Liebig-University in Giessen, Germany. The total sample pressures ranged from 8.8 to 3004.5 Torr with oxygen volume mixing ratios in nitrogen ranging between 0.057 and 0.62. An Exponential Power Gap (EPG) scaling law was used to calculate the N 2-broadening and N 2-line mixing coefficients. The line broadening and shift coefficients for the A-band of oxygen self-perturbed and perturbed by N 2 are modeled using semiclassical calculations based on the Robert-Bonamy formalism and two intermolecular potentials. These potentials involve electrostatic contributions including the hexadecapole moment of the molecules and (a) a simple dispersion contribution with one adjustable parameter to fit the broadening coefficients or (b) the atom-atom Lennard-Jones model without such adjustable parameters. The first potential leads to very weak broadening coefficients for high J transitions whereas the second potential gives much more improved results at medium and large J values, in reasonable agreement with the experimental data. For the line shifts which mainly arise in our calculation from the electronic state dependence of the isotropic potential, their general trends with increasing J values can be well predicted, especially from the first potential. From the theoretical results, we have derived air-broadening and air-induced shift coefficients with an agreement comparable to that obtained for O 2-O 2 and O 2-N 2.

Predoi-Cross, Adriana; Holladay, Christopher; Heung, Henry; Bouanich, Jean-Pierre; Mellau, Georg Ch.; Keller, Reimund; Hurtmans, Daniel R.

2008-09-01

390

Experimental Evidence of Threshold Effects in the Energy Loss of Protons in Carbon and Aluminum due to Inner Shell Ionization  

NASA Astrophysics Data System (ADS)

We explore the contributions of inner shell ionization to the energy loss of 7 to 270 keV protons in C and Al foils under experimental conditions such that the product of the observation angle and the projectile energy is kept constant. By normalizing these energy loss measurements to the energy loss in the forward direction we observe a pronounced rising behavior with increasing energy. This effect appears in the same range of energies where the respective K- and L-shell ionization cross sections of these elements show a similar threshold behavior. Based also on various theoretical considerations we interpret these results as clear evidence of the inner shell ionization contribution to the energy loss.

Famá, M.; Eckardt, J. C.; Lantschner, G. H.; Arista, N. R.

2000-11-01

391

Experimental study of energy transport between two granular gas thermostats  

NASA Astrophysics Data System (ADS)

We report on the energy transport between two coupled probes in contact with granular thermostats at different temperatures. In our experiment, two identical blades, which are electromechanically coupled, are immersed in two granular gases maintained in different non-equilibrium stationary states, characterized by different temperatures. First, we show that the energy flux from one probe to another is, in temporal average, proportional to the temperature difference, as in the case of equilibrium thermostats. Secondly, we observe that the instantaneous flux is highly intermittent and that fluctuations exhibit an asymmetry which increases with the temperature difference. Interestingly, this asymmetry, related to irreversibility, is correctly accounted for by a relation strongly evoking the Fluctuation Theorem. Our experiment is a simple macroscopic realisation, suitable for the study of energy exchanges between systems in non-equilibrium steady states.

Lecomte, Charles-Édouard; Naert, Antoine

2014-11-01

392

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

NASA Astrophysics Data System (ADS)

A new method for the chemical generation of atomic iodine intended for use in a chemical oxygen-iodine 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 of a computational model for the reaction system. The yield of iodine atoms in the nitrogen flow reached 70-100% under optimum experimental conditions. Gain was observed in preliminary experiments on the chemical generation of atomic iodine in a flow of singlet oxygen.

Špalek, Otomar; Jirásek, Vít.; ?enský, Miroslav; Kodymová, Jarmila; Jakubec, Ivo; Hager, Gordon D.

2002-08-01

393

A comparison of experimental and theoretical results for rotordynamic coefficients of four annular gas seals  

NASA Technical Reports Server (NTRS)

The test facility and initial test program developed to experimentally measure the fluid forces induced by annular gas seals is described. A comparison of theoretically predicted and experimentally obtained data for smooth and honeycomb seals is provided. And a comparison of experimental data from the tests of three smooth-rotor/smooth-stator seals is provided. The leakage of the working fluid through the seal, the pressure gradient along the seal length, entrance pressure-loss data, and rotordynamic coefficients provide a basis for comparison. A short discussion on seal theory is included, and various rotordynamic coefficient identification schemes are described.

Childs, D. W.; Nelson, C. C.; Elrod, D.; Nicks, C.

1985-01-01

394

Comparison of the beam-beam effects simulation with the experimental results obtained on VEPP-2M  

NASA Astrophysics Data System (ADS)

Beam-beam effects simulations for VEPP-2M have been carried out, and satisfactory agriment with the experimental results have been detected. Both simulations and expirements have been prepared in "strong-weak" case.

Nesterenko, I. N.; Shatilov, D. N.; Simonov, E. A.

1997-05-01

395

Cabauw Experimental Results from the Project for Intercomparison of Land-Surface Parameterization Schemes  

NASA Technical Reports Server (NTRS)

In the Project for Intercomparison of Land-Surface Parameterization Schemes phase 2a experiment, meteorological data for the year 1987 from Cabauw, the Netherlands, were used as inputs to 23 land-surface flux schemes designed for use in climate and weather models. Schemes were evaluated by comparing their outputs with long-term measurements of surface sensible heat fluxes into the atmosphere and the ground, and of upward longwave radiation and total net radiative fluxes, and also comparing them with latent heat fluxes derived from a surface energy balance. Tuning of schemes by use of the observed flux data was not permitted. On an annual basis, the predicted surface radiative temperature exhibits a range of 2 K across schemes, consistent with the range of about 10 W/m in predicted surface net radiation. Most modeled values of monthly net radiation differ from the observations by less than the estimated maximum monthly observational error (+/- 10 W/sq m). However, modeled radiative surface temperature appears to have a systematic positive bias in most schemes; this might be explained by an error in assumed emissivity and by models' neglect of canopy thermal heterogeneity. Annual means of sensible and latent heat fluxes, into which net radiation is partitioned, have ranges across schemes of 30 W/sq m and 25 W/sq m, respectively. Annual totals of evapotranspiration and runoff, into which the precipitation is partitioned, both have ranges of 315 mm. These ranges in annual heat and water fluxes were approximately halved upon exclusion of the three schemes that have no stomatal resistance under non-water-stressed conditions. Many schemes tend to underestimate latent heat flux and overestimate sensible heat flux in summer, with a reverse tendency in winter. For six schemes, root-mean-square deviations of predictions from monthly observations are less than the estimated upper bounds on observation errors (5 W/m for sensible beat flux and 10 W/m for latent heat flux). Actual runoff at the site is believed to be dominated by vertical drainage to ground water, but several schemes produced significant amounts of runoff as overland flow or interflow. There is a range across schemes of 184 mm (40% of total pore volume) in the simulated annual mean root-zone soil moisture. Unfortunately, no measurements of soil moisture were available for model evaluation. A theoretical analysis suggested that differences in boundary conditions used in various schemes are not sufficient to explain the large variance in soil moisture. However, many of the extreme values of soil moisture could be explained in terms of the particulars of experimental setup or excessive evapotranspiration.

Chen, Tian Hong; Henderson-Sellers, A.; Milly, P. C. D.; Pitman, A. J.; Beljaars, A. C. M.; Polcher, J.; Abramopoulos, F.; Boone, A.; Chang, S.; Chen, F.; Dai, Y.; Desborough, C. E.; Dickinson, R. E.; Duemenil, L.; Ek, M.; Garratt, J. R.; Gedney, N.; Gusev, Y. M.; Kim, J.; Koster, R.

1997-01-01

396

Cabauw experimental results from the Project for Intercomparison of Land-Surface Parameterization Schemes  

USGS Publications Warehouse

In the Project for Intercomparison of Land-Surface Parameterization Schemes phase 2a experiment, meteorological data for the year 1987 from Cabauw, the Netherlands, were used as inputs to 23 land-surface flux schemes designed for use in climate and weather models. Schemes were evaluated by comparing their outputs with long-term measurements of surface sensible heat fluxes into the atmosphere and the ground, and of upward longwave radiation and total net radiative fluxes, and also comparing them with latent heat fluxes derived from a surface energy balance. Tuning of schemes by use of the observed flux data was not permitted. On an annual basis, the predicted surface radiative temperature exhibits a range of 2 K across schemes, consistent with the range of about 10 W m-2 in predicted surface net radiation. Most modeled values of monthly net radiation differ from the observations by less than the estimated maximum monthly observational error (±10 W m-2). However, modeled radiative surface temperature appears to have a systematic positive bias in most schemes; this might be explained by an error in assumed emissivity and by models' neglect of canopy thermal heterogeneity. Annual means of sensible and latent heat fluxes, into which net radiation is partitioned, have ranges across schemes of 30 W m-2 and 25 W m-2, respectively. Annual totals of evapotranspiration and runoff, into which the precipitation is partitioned, both have ranges of 315 mm. These ranges in annual heat and water fluxes were approximately halved upon exclusion of the three schemes that have no stomatal resistance under non-water-stressed conditions. Many schemes tend to underestimate latent heat flux and overestimate sensible heat flux in summer, with a reverse tendency in winter. For six schemes, root-mean-square deviations of predictions from monthly observations are less than the estimated upper bounds on observation errors (5 W m-2 for sensible heat flux and 10 W m-2 for latent heat flux). Actual runoff at the site is believed to be dominated by vertical drainage to groundwater, but several schemes produced significant amounts of runoff as overland flow or interflow. There is a range across schemes of 184 mm (40% of total pore volume) in the simulated annual mean root-zone soil moisture. Unfortunately, no measurements of soil moisture were available for model evaluation. A theoretical analysis suggested that differences in boundary conditions used in various schemes are not sufficient to explain the large variance in soil moisture. However, many of the extreme values of soil moisture could be explained in terms of the particulars of experimental setup or excessive evapotranspiration.

Chen, T.H.; Henderson-Sellers, A.; Milly, P.C.D.; Pitman, A.J.; Beljaars, A.C.M.; Polcher, J.; Abramopoulos, F.; Boone, A.; Chang, S.; Chen, F.; Dai, Y.; Desborough, C.E.; Dickinson, R.E.; Dumenil, L.; Ek, M.; Garratt, J.R.; Gedney, N.; Gusev, Y.M.; Kim, J.; Koster, R.; Kowalczyk, E.A.; Laval, K.; Lean, J.; Lettenmaier, D.; Liang, X.; Mahfouf, J.-F.; Mengelkamp, H.-T.; Mitchell, K.; Nasonova, O.N.; Noilhan, J.; Robock, A.; Rosenzweig, C.; Schaake, J.; Schlosser, C.A.; Schulz, J.-P.; Shao, Y.; Shmakin, A.B.; Verseghy, D.L.; Wetzel, P.; Wood, E.F.; Xue, Y.; Yang, Z.-L.; Zeng, Q.

1997-01-01

397

Experimental analysis of an energy self sufficient ocean buoy utilizing a bi-directional turbine  

E-print Network

An experimental analysis of a Venturi shrouded hydro turbine for wave energy conversion. The turbine is designed to meet the specific power requirements of a, Woods Hole Oceanographic Institute offshore monitoring buoy ...

Gruber, Timothy J. (Timothy James)

2012-01-01

398

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

399

A numerical flow model and experimental results of a cryogenic micro-valve for distributed cooling applications  

NASA Astrophysics Data System (ADS)

This paper describes a steady numerical flow model and experimental gas flow results of a self-encapsulated, piezoelectrically actuated, cryogenic micro-valve for distributed cooling applications. Experimental flow data of the prototype micro-valve design is obtained for various gases at room temperature and for helium at near liquid nitrogen temperature. With a pressure differential of 100 kPa across the inlet and outlet, a prototype micro-valve is shown to modulate the flow of room temperature helium from 1200 to 0 sccm. Numerical flow results and experimental data agree well, with 60% of the data points falling within the range of ±10%.

Brosten, Tyler R.; Park, Jong M.; Evans, Allan T.; Rasmussen, Kristian; Nellis, Gregory F.; Klein, Sanford A.; Feller, Jeffery R.; Salerno, Louis; Gianchandani, Yogesh B.

2007-09-01

400

Chemical and Mechanical Alteration of Fractures: Micro-Scale Simulations and Comparison to Experimental Results  

NASA Astrophysics Data System (ADS)

Fractures are often the main pathways for subsurface fluid flow especially in rocks with low matrix porosity. Therefore, the hydro-mechanical properties of fractures are of fundamental concern for subsurface CO2 sequestration, enhanced geothermal energy production, enhanced oil recovery, and nuclear waste disposal. Chemical and mechanical stresses induced during these applications may lead to significant alteration of the hydro-mechanical properties of fractures. Laboratory experiments aimed at understanding the chemo-hydro-mechanical response of fractures have shown a range of results that contradict simple conceptual models. For example, under conditions favoring mineral dissolution, where one would expect an overall increase in permeability and fracture aperture, permeability increases under some conditions and decreases under others. Recent experiments have attempted to link these core-scale observations to the relevant small-scale processes occurring within fractures. Results suggest that the loss of mechanical strength in asperities due to chemical alteration may cause non-uniform deformation and alteration of fracture apertures. However, it remains difficult to directly measure the coupled chemical and mechanical processes that lead to alteration of contacting fracture surfaces, which challenges our ability to predict the long-term evolution of the hydro-mechanical properties of fractures. Here, we present a computational model that uses micro-scale surface roughness and explicitly couples dissolution and elastic deformation to calculate local alterations in fracture aperture under chemical and mechanical stresses. Chemical alteration of the fracture surfaces is modeled using a depth-averaged algorithm of fracture flow and reactive transport. Then, we deform the resulting altered fracture-surfaces using an algorithm that calculates the elastic deformation. Nonuniform dissolution may cause the location of the resultant force between the two contacting surfaces to shift away from the equilibrium location. We apply a relative rotation of the fracture surfaces to preserve force equilibrium during each iteration. The results of the model are compared with flow-through experiments conducted on fractured limestone cores and on analogue rough-surfaced KDP-glass fractures. The fracture apertures are mapped before, during (for some) and after the experiments. These detailed aperture measurements are used as input to our new coupled model. The experiments cover a wide range of transport and reaction conditions; some exhibit permeability increase due to channel formation and others exhibit fracture closure due to deformation of contacting asperities. Simulation results predict these general trends as well as the small-scale details in regions of contacting asperities.n example of an aperture field under chemical and mechanical alterations. The color scale is in microns.

Ameli, P.; Detwiler, R. L.; Elkhoury, J. E.; Morris, J. P.

2012-12-01

401

Prediction of sonic boom from experimental near-field overpressure data. Volume 1: Method and results  

NASA Technical Reports Server (NTRS)

A computerized procedure for predicting sonic boom from experimental near-field overpressure data has been developed. The procedure extrapolates near-field pressure signatures for a specified flight condition to the ground by the Thomas method. Near-field pressure signatures are interpolated from a data base of experimental pressure signatures. The program is an independently operated ODIN (Optimal Design Integration) program which obtains flight path information from other ODIN programs or from input.

Glatt, C. R.; Hague, D. S.; Reiners, S. J.

1975-01-01

402

Finite element simulation of cement-bone interface micromechanics; a comparison to experimental results  

PubMed Central

Recently, experiments have been performed to determine the micromechanical behavior of the cement-bone interface under tension-compression loading conditions. These experiments were simulated using finite element analysis (FEA) to test whether the micromechanical response of the cement-bone interface could be captured in micro-models. Cement-bone interface models were created of experimental specimens based upon micro-computed tomography data, including the complex interdigitated bone-cement morphology and simulated frictional contact at the interface. The models were subjected to a fully reversible tension-compression load, mimicking the experimental protocol. Similar to what was found experimentally, the simulated interface was stiffer in compression than in tension and the majority of displacement localized to the cement-bone interface. There was a weak correlation between the FEA predicted stiffness and the stiffness found experimentally, with average errors of 8.3 and 29.8% in tension and compression, respectively. The hysteresis behavior found experimentally was partially reproduced in the simulation by including friction at the cement-bone interface. Furthermore, stress analysis suggested that cement was more at risk of fatigue failure than bone, concurring with the experimental observation that more cracks were formed in the cement than in the bone. The current study provides information that may help to better understand the load transfer mechanisms taking place at the cement-bone interface. PMID:19340877

Janssen, Dennis; Mann, Kenneth A.; Verdonschot, Nico

2009-01-01

403

Finite element simulation of cement-bone interface micromechanics: a comparison to experimental results.  

PubMed

Recently, experiments were performed to determine the micromechanical behavior of the cement-bone interface under tension-compression loading conditions. These experiments were simulated using finite element analysis (FEA) to test whether the micromechanical response of the interface could be captured in micromodels. Models were created of experimental specimens based upon microcomputed tomography data, including the complex interdigitated bone-cement morphology and simulated frictional contact at the interface. The models were subjected to a fully reversed tension-compression load, mimicking the experimental protocol. Similar to what was found experimentally, the simulated interface was stiffer in compression than in tension, and the majority of displacement was localized to the cement-bone interface. A weak correlation was found between the FEA-predicted stiffness and the stiffness found experimentally, with average errors of 8 and 30% in tension and compression, respectively. The hysteresis behavior found experimentally was partially reproduced in the simulation by including friction at the cement-bone interface. Furthermore, stress analysis suggested that cement was more at risk of fatigue failure than bone, concurring with the experimental observation that more cracks were formed in the cement than in the bone. The current study provides information that may help explain the load transfer mechanisms taking place at the cement-bone interface. PMID:19340877

Janssen, Dennis; Mann, Kenneth A; Verdonschot, Nico

2009-10-01

404

Hazards by shock waves during explosive eruptions: preliminary results of experimental investigations.  

NASA Astrophysics Data System (ADS)

A recent study (Scolamacchia and Shouwenaars, 2009) investigated the nature of microscopic craters on the steel surface of a basketball pole left standing in one of the villages destroyed by the 1982 eruption of El Chichón volcano. The craters were attributed to the impacts of ash particles (70-280 ?m) accelerated by shock waves due to an efficient momentum coupling with a gas phase, such that a sudden expansion of the gas, caused by shock wave propagation, drag the particles up to speeds of 710 to 980 m/s. Several open questions existed on this kind of phenomena. Preliminary tests were performed to investigate the correlation between particle size and the high velocities calculated, based on inner deformation of the steel and crater geometry. We used a shock tube apparatus consisting of a high-pressure (HP) steel autoclave, pressurized with Ar gas, and a low pressure (LP) tank at atmospheric conditions. We used ash and lapilli bulk samples from El Chichón trachyandesites, and lapilli with random irregular shapes obtained by crushing and abrading dacitic blocks from pyroclastic flow deposits of Unzen volcano. The samples were placed inside an autoclave at ambient T and P, located between the HP autoclave and the LP tank. Steel plates (same type of the original impacted material), were fixed to the LP tank walls, 10 cm above the autoclave that contained the samples. Shock waves were generated by the sudden decompression of the Ar gas due to the systematical failure of a diaphragm (which separate the LP from the HP section). Air expansion accelerated the particles from below toward the steel plate. The speed of the particles was measured using a system of 4 copper wires conducting an electric signal. The signals dropped when the particles reached the wires. We used low pressure ranges (3.1 to 9.8 MPa) for all experimental runs, obtaining a range of particles velocities between 40 and 257 m/s. These velocities can be attained by pyroclastic density currents. Higher velocities (205 to 257 m/s) were obtained for smaller grain-sizes, in a range of fine lapilli-medium ash (2.8 to 177 ?m). Lower velocities, 40 m/s to 85 m/s, were attained by medium (8 mm) and fine lapilli (4 mm), respectively. These values seem not directly related to the the material composition. Impacts craters on steel plates were experimentally obtained, but we did not observe a modification of the steel inner structure, as observed in the original impacted pole. These results are in agreement with impacts occurred at low particle velocities, typical for gravity driven currents, as those reached in these experiments. We observed a great reduction in grain-size of samples recovered after all experiments with respect to the original material. Such evidence coud be due not only to the disruption of grains when impacting the metal plate, but also to processes stricly related to shock wave propagation and gas expansion. These preliminary results need to be further investigated.

Scolamacchia, Teresa; Alatorre Ibarguengoïtia, Miguel; Spieler, Oliver; Dingwell, Donald B.

2010-05-01

405

Optical oscillator strengths, mean excitation energy, shell corrections and experimental values for stopping power  

NASA Astrophysics Data System (ADS)

In a recent paper, Smith, Inokuti, Karstens and Shiles discussed optical oscillator strengths (OOS) of graphite, Al and Si and compared the mean excitation energy I obtained by integration to that from stopping power measurements. They found agreement for graphite and Al, but disagreement for Si. In this paper, we discuss the OOS of Al, Si, Cu and Au and compare the stopping powers calculated from these OOS (or from a single I-value), using program CasP40, directly to experimental stopping power values for protons between 10 and 80 MeV. We find that the choice of proper shell corrections is essential: since the shell correction built into CasP is too small, we take the correction for Al, Si and Cu from the BEST program of Berger and Bichsel. For Au, better results are obtained using Bonderup's shell correction. With these choices, we find fair agreement between experimental and calculated stopping data, both with the I-values from ICRU Report 49 and with OOS. Even in the case of Si, the stopping curve based on OOS is not in conflict with experimental data. In all cases, the curves calculated using SRIM are in good agreement with the data.

Paul, Helmut; Grande, Pedro L.; Smith, D. Y.

2009-08-01

406

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

407

Concept and first experimental results of a new ferromagnetic assist device for extra-aortic counterpulsation  

PubMed Central

OBJECTIVES Based on a ferromagnetic silicone cuff for extra-aortic counterpulsation, a new assist device concept was developed. The driving force is generated by an external magnetic field, which leads to contraction of a soft magnetic cuff. The force generation capacity of the device was tested in a silicone aorta model. METHODS Magnetic elastomers can be constructed through dispersion of micro- or nanoparticles in polymer matrices and were designed to act as soft actuators. Two magnetically active silicone cuffs were produced with a nanomagnet loading of 250 wt% (Cuff 1) and a micromagnet loading of 67 wt% (Cuff 2). The magnetic cuffs were applied on a silicone aorta model and contracted against hydrostatic pressure. RESULTS A full contraction of Cuff 1 was possible against a maximal hydrostatic pressure of 30 cmH2O (22 mmHg) at a magnetic flux density of 0.4 T (Tesla) and 65 cmH2O (48 mmHg) at a magnetic flux density of 1.2 T. A 50% contraction of Cuff 2 was possible against a maximal hydrostatic pressure of 80 cmH2O (59 mmHg) at a magnet-cuff-distance (MCD) of 0 cm. At MCDs of 1 and 2 cm a 50% contraction was possible against 33 cmH2O (24 mmHg) and 10 cmH2O (7 mmHg), respectively. CONCLUSIONS Combining the advantages of magnetic elastomers with the principle of extra-aortic counterpulsation in a new assist device concept avoids the need for anticoagulation (no contact with bloodstream). With regard to the magnetic principle of action, no intra- to extracorporeal connection is needed. More experimental work is needed to further increase the force generated by the silicone cuff and to transfer the device concept into an in vivo setting. PMID:24061069

Starck, Christoph T.; Becker, Jakob; Fuhrer, Roland; Sündermann, Simon; Stark, Jan Wendelin; Falk, Volkmar

2014-01-01

408

An experimental investigation of aluminum honeycomb as an energy absorber  

E-print Network

Thickness of specimen Mass PE Potential energy Summation Stroke Lead distance Time t tr V VI W t Trigger time Initial velocity Impact velocity Final velocity Trigger velocity Weight viii CHAPTER I INTRODUCTION Various types of systems... by the shearing of the cell walls during the crushing stroke by using an area in compression smaller than that of the specimen. This investigation has a practical application for use on the shock- absorption system in the astronauts' couch of a vehicle...

Bland, William Joseph

2012-06-07

409

Simulation of diurnal thermal energy storage systems: Preliminary results  

SciTech Connect

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. [Pacific Northwest Lab., Richland, WA (United States); Williams, H.R. [Univ. of Alaska, Fairbanks, AK (United States). Dept. of Mechanical Engineering

1994-12-01

410

Experimental Results from a Rational Reconstruction of MINSTREL Brandon Tearse Peter Mawhorter Michael Mateas Noah Wardrip-Fruin  

E-print Network

Experimental Results from a Rational Reconstruction of MINSTREL Brandon Tearse Peter Mawhorter results from a rational reconstruction project that is aimed at exploring the creative potential of Scott the variance of the output space and the ratio of sensible to nonsensical results (as determined by hand

California at Santa Cruz, University of

411

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

412

Experimental and theoretical results on electron emission in collisions between He targets and dressed Liq+ (q = 1, 2) projectiles  

NASA Astrophysics Data System (ADS)

We investigate experimentally and theoretically the electron emission in collisions between He atoms and L{{i}^{q+}} (q = 1, 2) projectiles at intermediate to high incident energies. We report on measured absolute values of double-differential cross-sections, as a function of the emitted electron energy and angle, at a collision energy of 440 keV u-1. The different contributions from target ionization, projectile ionization, and simultaneous target-projectile ionization are calculated with the quantum-mechanical continuum distorted wave and continuum distorted wave-eikonal initial state models, and with classical trajectory Monte Carlo simulations. There is an overall good agreement of the calculations with the experimental data for electron emission cross-sections.

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

2014-08-01

413

Numerical and experimental assessment of turbulent kinetic energy in an aortic coarctation.  

PubMed

The turbulent blood flow through an aortic coarctation in a 63-year old female patient was studied experimentally using magnetic resonance imaging (MRI), and numerically using computational fluid dynamics (CFD), before and after catheter intervention. Turbulent kinetic energy (TKE) was computed in the numerical model using large eddy simulation and compared with direct in vivo MRI measurements. Despite the two totally different methods to obtain TKE values, both quantitative and qualitative results agreed very well. The results showed that even though both blood flow rate and Reynolds number increased after intervention, total turbulent kinetic energy levels decreased in the coarctation. Therefore, the use of the Reynolds number alone as a measure of turbulence in cardiovascular flows should be used with caution. Furthermore, the change in flow field and kinetic energy were assessed, and it was found that before intervention a jet formed in the throat of the coarctation, which impacted the arterial wall just downstream the constriction. After intervention the jet was significantly weaker and broke up almost immediately, presumably resulting in less stress on the wall. As there was a good agreement between measurements and numerical results (the increase and decrease of integrated TKE matched measurements almost perfectly while peak values differed by approximately 1mJ), the CFD results confirmed the MRI measurements while at the same time providing high-resolution details about the flow. Thus, this preliminary study indicates that MR-based TKE measurements might be useful as a diagnostic tool when evaluating intervention outcome, while the detailed numerical results might be useful for further understanding of the flow for treatment planning. PMID:23746596

Lantz, Jonas; Ebbers, Tino; Engvall, Jan; Karlsson, Matts

2013-07-26

414

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

415

Experimental Results On The Influence of Vegetation In The Threshold Movement.  

NASA Astrophysics Data System (ADS)

The riverine vegetation is an important actuation in the restoration of degradated riverbeds and river management. One of the most important factors of riverbanks sta- bility is related to the deposition or erosion induced by the presence of vegetation. To study this kind of phenomena we carried out a set of experiments with the objective to found the threshold movement of uniform sand in a vegetated bed. A 2.5 m wide flume was used with different combination of flow discharges and vegetation density. In order to model the flexibility of natural riverine plants, plastic strips were placed in a uniform, random staggered pattern. Also an analysis of the velocity profile and the Reynolds stresses was presented. An analysis of the stresses distribution was used to determine the drag force absortion due to the presence of plants. For this, a NDV velocimeter device was used. A simple study of flow resistance factor was made in order to its direct application for engineering calculations, like manning and darcy.weissbach resistance factor. A complete turbulence analysis was elaborated to a deeper understand of the behavior of the flow in presence of plants; it is, integral lenghtscales and density plant length- scale relationship, turbulent intensities distribution and energy spectrum. Our results agree with Nezu (2001) and Nepf (2000) works.

Velasco, D.; Bateman, A.; Demedina, V.; Raffaeli, S.

416

An experimental evaluation of surrounding RF energy harvesting devices  

Microsoft Academic Search

In this paper, we present a study of RF energy harvesting devices. The surrounding RF power density was measured. The average of the total radiation power density in broadband (1GHz-3.5GHz) is in the order of -12dBm\\/m2 (63?W\\/m2). The maximum of the RF density power is measured in 1.8GHz-1.9GHz frequency band, it is around -14dBm\\/m2. Two rectifiers have been designed and

D. Bouchouicha; M. Latrach; F. Dupont; L. Ventura

2010-01-01

417

Stability and spring constant investigation for micromachined inductive suspensions: theoretical analysis vs. experimental results  

NASA Astrophysics Data System (ADS)

We present a linear analytical model coupled with experimental analysis to discuss stability of a levitated proof mass (PM) in a micromachined inductive suspension (MIS), which has been previously introduced and characterized. The model is a function of the MIS geometry, describes the dynamics of a levitated disk-shaped PM near the equilibrium point, and predicts conditions for stable levitation. The experimental setup directly measures the lateral component of the Lorentz force, which has a stabilization role in the MIS structure, as well as the vertical levitation force. The experimental setup is further used to derive mechanical parameters such as stiffness values relative to lateral, vertical and angular displacements, proven to be in excellent agreement with the values predicted by the analytical model.

Poletkin, K.; Lu, Z.; den Hartogh, B.; Wallrabe, U.; Badilita, V.

2014-11-01

418

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

419

Experimental search for low energy nuclear excitation by femtosecond plasma  

NASA Astrophysics Data System (ADS)

New experimental data on the secondary electron yield from a thin layer of 57Fe irradiated by emission of the hot dense plasma source created by femtosecond laser pulses with intensity of 1017 W cm?2 is presented. Plasma source hard x-ray and electron fluxes are measured for the source characterization. Thorough statistical analysis of the delayed secondary electron spectrum from the 57Fe layer in the 20–100 ns temporal window allows exclusion of the ‘null’ hypothesis of the random character of the differences of this spectrum with that obtained using a 56Fe target. Thus, statistically valid maxima at ?5.8 and 7.4 keV can be attributed to the decay of the isomeric nuclear state of 57Fe (3/2?, 14.41 keV, 98 ns) by the internal conversion process through the atomic K-shell (maximum at 7.4 keV), followed by the Auger process (maximum at 5.8 keV).

Chefonov, O. V.; Ovchinnikov, A. V.; Yurkevich, A. A.; Romashevskiy, S. A.; Shulyapov, S. A.; Petrovskiy, V. P.; Savel’ev, A. B.; Agranat, M. B.

2014-11-01

420

Experimental Results of Olive Pits Gasification in a Fixed Bed Downdraft Gasifier System  

Microsoft Academic Search

Environmental legislation and interest in using newly utilized renewable biomass energy sources in small-scale downdraft biomass gasifiers have stimulated this research work. Biomass gasification for the production of green and clean energy generation in the form of electricity and\\/or heat is a viable alternative to fossil fuels and a clean technology, which can reduce greenhouse gas emissions and facilitate closure

Murat Dogru

2012-01-01