Science.gov

Sample records for energy experimental results

  1. Energy-resolved computed tomography: first experimental results

    NASA Astrophysics Data System (ADS)

    Shikhaliev, Polad M.

    2008-10-01

    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.

  2. Recent theoretical and experimental results on inertial fusion energy physics

    NASA Astrophysics Data System (ADS)

    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

    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.

  3. Comments on experimental results of energy confinement of tokamak plasmas

    SciTech Connect

    Chu, T.K.

    1989-04-01

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

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

    NASA Technical Reports Server (NTRS)

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

    1975-01-01

    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.

  5. High energy nucleus-nucleus collisions at CERN: Signatures, physical observables and experimental results

    SciTech Connect

    Harris, J.W.

    1988-02-01

    Experimental results on high energy nucleus-nucleus collisions have become available with the recent experiments at CERN utilizing 200 GeV/n oxygen and sulfur beams. Physics motivations for these experiments are presented: a description of predicted signatures for possible formation of a quark-gluon plasma and physical observables that are expected to provide important information for understanding the dynamics of these collisions. A presentation will be made of some of the first experimental results to emerge from this new field. 28 refs., 9 figs.

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

    NASA Technical Reports Server (NTRS)

    Jacqmin, David

    1995-01-01

    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.

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

    NASA Technical Reports Server (NTRS)

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

    1975-01-01

    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.

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

    NASA Technical Reports Server (NTRS)

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

    1995-01-01

    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).

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

    NASA Astrophysics Data System (ADS)

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

    2015-03-01

    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.

  10. Multigan®: first experimental results.

    PubMed

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

    2012-02-01

    A new design of a multicharged ion source based on the MONO1000 ECRIS has been presented at the last ECR ion source (ECRIS) Workshop 2010. [L. Maunoury et al., in Proceedings of the XIXth International Workshop on ECR Ion Sources, Grenoble, France, 23-26 August 2010] This source has not only two opening at both ends but also a large space in the middle of the source enabling a direct contact with the ECR plasma. The source has been assembled mechanically and put on a test bench at the Pantechnik company. The primary tests have shown that the plasma ignition occurred at low pressure (10(-6) mbar) and low RF power (10 W). The first experimental results ( = 1.30 for Ar and 1.85 for Xe) demonstrated the potential of this ion source in production of multicharged ion beams. PMID:22380185

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

    SciTech Connect

    Sorrentino, Luigi; Masiani, Renato; Benedetti, Stefano

    2008-07-08

    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.

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

    NASA Technical Reports Server (NTRS)

    Tolbert, Carol

    2000-01-01

    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.

  13. Energy Transfer with Hydrogen and Superconductivity - The Review of the First Experimental Results

    NASA Astrophysics Data System (ADS)

    Vysotsky, V. S.; Antyukhov, I. V.; Firsov, V. P.; Blagov, E. V.; Kostyuk, V. V.; Nosov, A. A.; Fetisov, S. S.; Zanegin, S. Yu.; Rachuk, V. S.; Katorgin, B. I.

    The transfer of massive amounts of both electrical and chemical power over long distances will present a major challenge for the global energy enterprise in future. Attraction of hydrogen is apparent as a chemical energy agent, possessing among the highest energy density content of various common fuels, whose combustive "waste" is simply water. The usage of "gratis" cold to cool a superconducting cable made of proper superconductor permits to deliver extra electrical power with the same line. This, rather old theoretical idea recently found its experimental realization. The team of Russian institutes and organizations with using Italian-produced MgB2 wire has made and successfully tested two hybrid energy transfer lines with liquid hydrogen as a chemical source of power and superconducting cable as a source of electricity. The first line has been tested in 2011. It has length ?10 m, maximum liquid hydrogen flow ?250 g/s and maximum current of MgB2 superconducting cable 2600 A @ 20K. This test was the first experimental proof of conception of the hybrid energy transfer line. The second line has been tested in October 2013. It has length ?30 m. The new MgB2 cable has critical current at 21 K ?3500 A and successfully passed high voltage DC test of 50 kV. New hydrogen cryostat has three sections with different types of thermal insulation in each section. The idea of hybrid energy transfer is formulated and details of first experiments are reviewed.

  14. Characterization of an extrapolation chamber for low-energy X-rays: experimental and Monte Carlo preliminary results.

    PubMed

    Neves, Lucio P; Silva, Eric A B; Perini, Ana P; Maidana, Nora L; Caldas, Linda V E

    2012-07-01

    The extrapolation chamber is a parallel-plate ionization chamber that allows variation of its air-cavity volume. In this work, an experimental study and MCNP-4C Monte Carlo code simulations of an ionization chamber designed and constructed at the Calibration Laboratory at IPEN to be used as a secondary dosimetry standard for low-energy X-rays are reported. The results obtained were within the international recommendations, and the simulations showed that the components of the extrapolation chamber may influence its response up to 11.0%. PMID:22182629

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

    SciTech Connect

    Mashnik, Stepan G

    2010-11-22

    MCNP6, the latest and most advanced LANL transport code representing a recent merger of MCNP5 and MCNPX, has been Validated and Verified (V and V) against a variety of intermediate and high-energy experimental data and against results by different versions of MCNPX and other codes. In the present work, we V andV MCNP6 using mainly the latest modifications of the Cascade-Exciton Model (CEM) and of the Los Alamos version of the Quark-Gluon String Model (LAQGSM) event generators CEM03.02 and LAQGSM03.03. We found that MCNP6 describes reasonably well various reactions induced by particles and nuclei at incident energies from 18 MeV to about 1 TeV per nucleon measured on thin and thick targets and agrees very well with similar results obtained with MCNPX and calculations by CEM03.02, LAQGSM03.01 (03.03), INCL4 + ABLA, and Bertini INC + Dresner evaporation, EPAX, ABRABLA, HIPSE, and AMD, used as stand alone codes. Most of several computational bugs and more serious physics problems observed in MCNP6/X during our V and V have been fixed; we continue our work to solve all the known problems before MCNP6 is distributed to the public.

  16. Majorana Thermosyphon Prototype Experimental Results

    SciTech Connect

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

    2010-12-17

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

  17. Experimental results from the small isochronous ring

    SciTech Connect

    Eduard Pozdeyev

    2005-05-01

    The Small Isochronous Ring (SIR) is a compact, low-energy storage ring designed to investigate the beam dynamics of high-intensity isochronous cyclotrons and synchrotrons at the transition energy. The ring was developed at Michigan State University (MSU) and has been operational since December 2003. It stores 20 keV hydrogen beams with a peak current of 10-20 microamps for up to 200 turns. The transverse and longitudinal profiles of extracted bunches are measured with an accuracy of approximately 1 mm. The high accuracy of the measurements makes the experimental data attractive for validation of multi-particle space charge codes. The results obtained in the ring show a fast growth of the energy spread induced by the space charge forces. The energy spread growth is accompanied by a breakup of the beam bunches into separated clusters that are involved in the vortex motion specific to the isochronous regime. The experimental results presented in the paper show a remarkable agreement with simulations performed with the code CYCO. In this paper, we discuss specifics of space charge effects in the isochronous regime, present results of experiments in SIR, and conduct a detailed comparison of the experimental data with results of simulations.

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

    NASA Technical Reports Server (NTRS)

    Morgan, Harry L., Jr.

    2002-01-01

    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.

  19. Experimental electrochemical capacitor test results

    SciTech Connect

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

    1998-07-01

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

  20. Recent Experimental Results from HELIOS

    NASA Astrophysics Data System (ADS)

    Wuosmaa, A. H.

    2013-03-01

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

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

    E-print Network

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

    1994-01-01

    Recently third-party financing has become a popular mechanism for funding energy conservation retrofits in commercial/institutional buildings. Although many successful projects have been heralded by the press quite a few ...

  2. Isospin diffusion in semi-peripheral $^{58}Ni$ + $^{197}Au$ collisions at intermediate energies (I): Experimental results

    E-print Network

    E. Galichet; M. F. Rivet; B. Borderie; M. Colonna; R. Bougault; A. Chbihi; R. Dayras; D. Durand; J. D. Frankland; D. C. R. Guinet; P. Lautesse; N. Le Neindre; O. Lopez; L. Manduci; M. Parlog; E. Rosato; B. Tamain; E. Vient; C. Volant; J. P. Wieleczko

    2008-12-15

    Isospin diffusion in semi-peripheral collisions is probed as a function of the dissipated energy by studying two systems $^{58}Ni$ + $^{58}Ni$ and $^{58}Ni$ + $^{197}Au$, over the incident energy range 52-74\\AM. A close examination of the multiplicities of light products in the forward part of phase space clearly shows an influence of the isospin of the target on the neutron richness of these products. A progressive isospin diffusion is observed when collisions become more central, in connection with the interaction time.

  3. Pattern preserving deposition: Experimental results and modeling

    NASA Astrophysics Data System (ADS)

    Castez, Marcos F.; Fonticelli, Mariano H.; Azzaroni, Omar; Salvarezza, Roberto C.; Solari, Hernán G.

    2005-09-01

    In this work we discuss pattern-preserving growth during metal deposition from the vapor on micro/nano-structured metal substrates. Experimental results for Cu deposition on patterned Cu substrates show pattern preserving growth or pattern destruction depending on the incident angle. We introduce a mesoscopic 1+1 dimensional model including deposition flow (directed and isotropic), surface diffusion and shadowing effects that account for the experimental growth data. Moreover, simulations on post-deposition annealing, for high aspect-ratio patterns show departures from the predictions of the linear theory for surface diffusion.

  4. A critical review of RHIC experimental results

    NASA Astrophysics Data System (ADS)

    Trainor, Thomas A.

    2014-07-01

    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.

  5. Fuel-rich, catalytic reaction experimental results

    NASA Technical Reports Server (NTRS)

    Rollbuhler, R. James

    1991-01-01

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

  6. Experimental results on advanced rotary desiccant dehumidifiers

    SciTech Connect

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

    1986-08-01

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

  7. Bioreactor landfills: experimental and field results.

    PubMed

    Warith, Mostafa

    2002-01-01

    Bioreactor landfills allow a more active landfill management that recognizes the biological, chemical and physical processes involved in a landfill environment. This paper presents the results of an experimental study carried out to determine the effect of solid waste size, leachate recirculation and nutrient balance on the rate of municipal solid waste (MSW) biodegradation. Higher rates of MSW biodegradation eventually cause a reduction of the contaminant life span of the landfill and decrease in the cost of long term monitoring. The study indicated that the smaller the size of the MSW the faster the biodegradation rate of the waste. In addition, the paper presents the results of leachate recirculation on solid waste biodegradation in a full-scale landfill site, which is located in Nepean, Ontario, Canada. The leachate was recirculated into the landfilled solid waste for 8 years through infiltration lagoons. Similar results to those obtained in the laboratory scale experiments were noted. The average pH of the leachate in the early stages of recirculation was on the acidic range of the pH scale, however, the pH value was in the range of 7-8 after 2 years of leachate recirculation. The concentration of chloride remained fairly constant at about 1000 mg/l during the leachate recirculation period. A decreasing trend of the organic load, measured as biological oxygen demand and chemical oxygen demand, was observed. Recovery of landfill air space was also noted because of the enhanced subsidence and decomposition of the solid waste. PMID:11942706

  8. Experimental Results of the Small Isochronous Ring

    SciTech Connect

    Felix Martin; Richard York; Juan Rodriguez; Eduard Pozdeyev

    2004-06-01

    The Small Isochronous Ring (SIR) has been in operation since December 2003. The main purpose of this ring, developed and built at the National Superconducting Cyclotron Laboratory (NSCL) at Michigan State University (MSU), is to simulate the dynamics of intense beams in large accelerators. To observe the same effects, the beam power needed in SIR is orders of magnitude lower and the time scale is much longer than in the full scale machines. These differences simplify the design and operation of the accelerator. The ring measurements can be used to validate the results of space charge codes. After a variable number of turns, the injected hydrogen bunch (with energies up to 30 keV) is extracted and its longitudinal profile is measured using a fast Faraday cup. We present a summary of the design, the results of the first six months of operation and the comparison with selected space charge codes.

  9. Overview of recent experimental results on MAST

    NASA Astrophysics Data System (ADS)

    Lloyd, B.; Ahn, J.-W.; Akers, R. J.; Appel, L. C.; Arends, E. R.; Axon, K. B.; Buttery, R. J.; Byrom, C.; Carolan, P. G.; Challis, C.; Ciric, D.; Conway, N. J.; Cox, M.; Counsell, G. F.; Cunningham, G.; Darke, A.; Dnestrovskij, A.; Dowling, J.; Dunstan, M. R.; Field, A. R.; Fielding, S. J.; Gee, S.; Gryaznevich, M. P.; Helander, P.; Hole, M.; Hood, M. B.; Jones, P. A.; Kirk, A.; Lehane, I. P.; Maddison, G. P.; Manhood, S. J.; Martin, R.; McArdle, G. J.; McClements, K. G.; McGrath, M. A.; Meyer, H.; Morris, A. W.; Nielsen, S. K.; Nightingale, M.; Patel, A.; Pinfold, T.; Price, M. N.; Qin, J.; Ribeiro, C.; Roach, C. M.; Robinson, D. C.; Sauter, O.; Shevchenko, V.; Shibaev, S.; Stammers, K.; Sykes, A.; Tabasso, A.; Taylor, D.; Tournianski, M. R.; Turri, G.; Valovic, M.; Voss, G.; Walsh, M. J.; Warder, S.; Watkins, J. R.; Wilson, H. R.; Yang, Y.; You, S.; MAST, the; NBI Teams

    2003-12-01

    The low aspect ratio of the mega amp spherical tokamak (MAST) allows differentiation between different forms of the H-mode threshold scaling. With optimized fuelling using inboard puffing, and a connected double null divertor (DND) magnetic configuration, the H-mode power threshold data lie about 1.7 times higher than recent scaling laws. Slight magnetic configuration changes, of the order of the ion Larmor radius, around a connected DND significantly influence H-mode access. H-mode confinement in discharges with low frequency edge localized modes (ELMs) is generally consistent with international scaling laws, e.g. IPB98(y,2). Strong indications of both particle and energy internal transport barriers have been seen. Normalized beta values bgrN > 5 have been obtained, approaching the ideal n = 1 no wall external kink stability limit. Sawtooth triggered neo-classical tearing modes have been observed; numerical modelling of the island evolution reproduces mode behaviour well and confirms the significance of stabilizing field curvature effects. Divertor power loading studies, including transient effects due to ELMs, show a strong bias of power efflux to the outboard targets, where it is more easily handled. ELM energy losses, Dgr WELM, are less than 4% of the stored energy in all regimes explored so far, but ELM effluxes extending 30 cm outside the outboard separatrix have been measured. Toroidally asymmetric divertor biasing resulted in significant broadening of the Dagr profile on the biased components and a reduction in the total power to the unbiased components. Halo current magnitudes and asymmetries are generally small compared with conventional tokamaks; recent measurements show that the plasma behaves more as a voltage source than a current source. Initial neutral beam current drive experiments indicate non-inductively driven current values (INBI ~ 0.3Ip) comparable with code predictions.

  10. 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...

  11. Preliminary experimental results from a MARS Micro-CT system.

    PubMed

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

    2012-01-01

    The Medipix All Resolution System (MARS) system is a commercial spectral/multi-energy micro-CT scanner designed and assembled by the MARS Bioimaging, Ltd. in New Zealand. This system utilizes the state-of-the-art Medipix photon-counting, energy-discriminating detector technology developed by a collaboration at European Organization for Nuclear Research (CERN). In this paper, we report our preliminary experimental results using this system, including geometrical alignment, photon energy characterization, protocol optimization, and spectral image reconstruction. We produced our scan datasets with a multi-material phantom, and then applied ordered subset-simultaneous algebraic reconstruction technique (OS-SART) to reconstruct images in different energy ranges and principal component analysis (PCA) to evaluate spectral deviation among the energy ranges. PMID:22635175

  12. Comparison between theoretical and experimental results for energy states of two-dimensional electron gas in pseudomorphically strained InAs high-electron-mobility transistors

    NASA Astrophysics Data System (ADS)

    Nishio, Yui; Tange, Takahiro; Hirayama, Naomi; Iida, Tsutomu; Takanashi, Yoshifumi

    2014-01-01

    The energy states of a two-dimensional electron gas (2DEG) in high-electron-mobility transistors with a pseudomorphically strained InAs channel (PHEMTs) were analyzed rigorously using a recently established theory that takes into account the nonparabolicity of the conduction band of the channel layer. The sheet density of the 2DEG in InxGa1-xAs-PHEMTs and the drain I-V characteristics of those devices were calculated theoretically and compared with the density and characteristics obtained experimentally. Not only the calculated threshold voltage (VTH) but also the calculated transconductance agreed fairly well with the corresponding values obtained experimentally. When the effects of the compositions of the InxGa1-xAs subchannel layer in the composite channel and the channel layer on energy states of 2DEG were investigated in order to establish a guiding principle for a design of the channel structure in PHEMTs, it was found that VTH is determined by the effective conduction-band offset energy ?EC between the InAlAs barrier and the channel layers.

  13. Experimental rotordynamic coefficient results for honeycomb seals

    NASA Technical Reports Server (NTRS)

    Elrod, David A.; Childs, Dara W.

    1988-01-01

    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.

  14. 1 Experimental Results in Robust Lateral

    E-print Network

    Abstract Vehicle lateral dynamics are affected by vehicle mass, longitudin* *al velocity, vehicle as on a test vehicle. Test results for experime* *nts conducted on an instrumented track are presented Vehicles Raymond H. Byrne Chaouki T. Abdallah Peter Dorato Sandia

  15. Adaptive structures - Test hardware and experimental results

    NASA Technical Reports Server (NTRS)

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

    1990-01-01

    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.

  16. Selected experimental results from heavy-ion collisions at LHC

    DOE PAGESBeta

    Singh, Ranbir; Kumar, Lokesh; Netrakanti, Pawan Kumar; Mohanty, Bedangadas

    2013-01-01

    We review a subset of experimental results from the heavy-ion collisions at the Large Hadron Collider (LHC) facility at CERN. Excellent consistency is observed across all the experiments at the LHC (at center of mass energysNN=2.76 TeV) for the measurements such as charged particle multiplicity density, azimuthal anisotropy coefficients, and nuclear modification factor of charged hadrons. Comparison to similar measurements from the Relativistic Heavy Ion Collider (RHIC) at lower energy (sNN=200 GeV) suggests that the system formed at LHC has a higher energy density and larger system size and lives for a longer time. These measurements aremore »compared to model calculations to obtain physical insights on the properties of matter created at the RHIC and LHC.« less

  17. Numerical taxonomy on data: Experimental results

    SciTech Connect

    Cohen, J.; Farach, M.

    1997-12-01

    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.

  18. Experimental results for absolute cylindrical wavefront testing

    NASA Astrophysics Data System (ADS)

    Reardon, Patrick J.; Alatawi, Ayshah

    2014-09-01

    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.

  19. On collisional disruption - Experimental results and scaling laws

    NASA Technical Reports Server (NTRS)

    Davis, Donald R.; Ryan, Eileen V.

    1990-01-01

    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.

  20. Theoretical and Experimental Results Regarding LENR/CF

    SciTech Connect

    Robert W. Bass; Wm. Stan Gleeson

    2000-11-12

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

  1. Experimental Test Results of the Energy Efficient Transport (EET) Flap-Edge Vortex Model in the Langley Low-Turbulence Pressure Tunnel

    NASA Technical Reports Server (NTRS)

    Morgan, Harry L., Jr.

    2002-01-01

    This report presents the results of a test conducted in the Langley Low-Turbulence Pressure Tunnel to measure the flow field properties of a flap-edge vortex. The model was the EET (Energy Efficient Transport) Flap-Edge Vortex Model, which consists of a main element and a part-span, single-slotted trailing-edge flap. The model surface was instrumented with several chordwise and spanwise rows of pressure taps on each element. The off-body flow field velocities were to be measured in several planes perpendicular to the flap edge with a laser velocimetry system capable of measuring all three components in coincidence. However, due to seeding difficulties, the preliminary laser data did not have sufficient accuracy to be suitable for presentation; therefore, this report presents only the tabulated and plotted surface pressure data. In addition, the report contains a detail description of the model which can be used to generate accurate CFD grid structures.

  2. Non-shock initiation model for explosive families : experimental results.

    SciTech Connect

    Anderson, Mark U.; Jensen, Charles B.; Todd, Steven N.; Hugh, Chance G.; Caipen, Terry L.

    2010-03-01

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

  3. Non-Shock Initiation Model for Explosive Families: Experimental Results

    NASA Astrophysics Data System (ADS)

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

    2009-12-01

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

  4. Acoustic analysis in Mudejar-Gothic churches: Experimental results

    NASA Astrophysics Data System (ADS)

    Galindo, Miguel; Zamarreño, Teófilo; Girón, Sara

    2005-05-01

    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. .

  5. Acoustic analysis in Mudejar-Gothic churches: experimental results.

    PubMed

    Galindo, Miguel; Zamarreño, Teófilo; Girón, Sara

    2005-05-01

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

  6. Results of experimental investigations of cobalt beta decay rate variation

    E-print Network

    Baurov, Yu A; Nikitin, V A; Dunin, V B; Tihomirov, V V; Sergeev, S V; Demchuk, N A

    2013-01-01

    Results of long-term investigations of variation of cobalt beta decay rate from 28.12.2010 till 08.02.2012 are presented. The scintillation spectrometer with two LaBr3 detectors is used to register of gamma-quanta with energy 1.173 and 1.332 MeV accompanying cobalt beta decay. Counting rate of each detector and their gamma-quanta coincidence are collected in successive time intervals 10 s. The statistical Kolmogorov-Smirnov method for data analysis is used. Temperature influence on experimental results is also analyzed. Deviations of beta decay counting rate from constant distribution during the days were detected in those decades: from 11.03 to 21.03 with significance level a = 0.1; from 22.04 to 02.05 with a=0.0125; from 24.06 to 04.07 with a=0.05; from 04.08 to 14.08 with a=0.05.

  7. Results of experimental investigations of cobalt beta decay rate variation

    E-print Network

    Yu. A. Baurov; A. Yu. Baurov; A. Yu. Baurov; V . A. Nikitin; V. B. Dunin; V. V. Tihomirov; S. V. Sergeev; N. A. Demchuk

    2013-04-25

    Results of long-term investigations of variation of cobalt beta decay rate from 28.12.2010 till 08.02.2012 are presented. The scintillation spectrometer with two LaBr3 detectors is used to register of gamma-quanta with energy 1.173 and 1.332 MeV accompanying cobalt beta decay. Counting rate of each detector and their gamma-quanta coincidence are collected in successive time intervals 10 s. The statistical Kolmogorov-Smirnov method for data analysis is used. Temperature influence on experimental results is also analyzed. Deviations of beta decay counting rate from constant distribution during the days were detected in those decades: from 11.03 to 21.03 with significance level a = 0.1; from 22.04 to 02.05 with a=0.0125; from 24.06 to 04.07 with a=0.05; from 04.08 to 14.08 with a=0.05.

  8. Experimental Results from a Resonant Dielectric Laser Accelerator

    NASA Astrophysics Data System (ADS)

    Yoder, Rodney; McNeur, Joshua; Sozer, Esin; Travish, Gil; Hazra, Kiran Shankar; Matthews, Brian; England, Joel; Peralta, Edgar; Wu, Ziran

    2015-04-01

    Laser-powered accelerators have the potential to operate with very large accelerating gradients (~ GV/m) and represent a path toward extremely compact colliders and accelerator technology. Optical-scale laser-powered devices based on field-shaping structures (known as dielectric laser accelerators, or DLAs) have been described and demonstrated recently. Here we report on the first experimental results from the Micro-Accelerator Platform (MAP), a DLA based on a slab-symmetric resonant optical-scale structure. As a resonant (rather than near-field) device, the MAP is distinct from other DLAs. Its cavity resonance enhances its accelerating field relative to the incoming laser fields, which are coupled efficiently through a diffractive optic on the upper face of the device. The MAP demonstrated modest accelerating gradients in recent experiments, in which it was powered by a Ti:Sapphire laser well below its breakdown limit. More detailed results and some implications for future developments will be discussed. Supported in part by the U.S. Defense Threat Reduction Agency (UCLA); U.S. Dept of Energy (SLAC); and DARPA (SLAC).

  9. Experimental Results on Jets in pA

    NASA Astrophysics Data System (ADS)

    Appelt, Eric

    2015-04-01

    The experimentally observed reduction of jet yields in ultrarelativistic heavy ion (AA) collisions relative to proton-proton (pp) collisions is widely interpreted in terms of energy loss of a hard scattered parton traversing a quark-gluon plasma (QGP) before fragmenting into a jet of hadrons. In order to constrain proposed mechanisms of energy loss, a variety of measurements are needed that quantify both how the jet yields and jet structure are modified in the medium. However, jets may also be modified by differences in the initial state of the nucleus relative to that of the proton. The precise determination of the QGP properties relies on disentangling these additional modifications, collectively termed ``cold nuclear matter'' effects, from energy loss in the QGP. Collisions between heavy ions and protons (pA) provide a potential control environment where cold nuclear matter effects should be present, but QGP formation is generally not expected to occur. In this talk, an overview of recent jet results from proton-lead collisions produced at the LHC will be given. The yield of inclusive jets and distributions of dijet pairs are shown to be compatible with generally accepted theoretical expectations, although significant modification is observed when yields are measured from specific centrality classes of pA collision events. Some measurements of high-pT charged hadron yields suggest a larger modification in pA collisions relative to pp collisions than for inclusive jet yields. The potential implications of this difference along with other measurements relating to jet structure will be discussed.

  10. Experimental results on atomic oxygen corrosion of silver

    NASA Technical Reports Server (NTRS)

    Fromhold, Albert T.

    1988-01-01

    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.

  11. Ultrasonic radiation from wedges of cubic profile: Experimental results.

    PubMed

    Anderson, Brian E; Remillieux, Marcel C; Le Bas, Pierre-Yves; Ulrich, T J; Pieczonka, Lukasz

    2015-12-01

    This paper presents experimental results demonstrating the increase in ultrasonic radiation obtained from a wedge of cubic profile relative to a plate of uniform thickness. The wedge of cubic profile provides high efficiency sound radiation matching layer from a mounted piezoelectric transducer into the surrounding air. Previous research on structures with indentations of power-law profile has focused on vibration mitigation using the so called "acoustic black-hole" effect, whereas here such structures are used to enhance ultrasonic radiation. The work provides experimental verification of the numerical results of Remillieux et al. (2014). PMID:26166628

  12. Comparison of calculated and experimental results of fragmenting cylinder experiments

    SciTech Connect

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

    2000-06-02

    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.

  13. CP violation in the B meson system: recent experimental results

    E-print Network

    Gautier Hamel de Monchenault

    2001-12-05

    Recent experimental results on CP violation in the study of B meson decays are reviewed. The emphasis is put on the recent measurements of the CP parameter sin2beta by the BABAR and BELLE experiments at asymmetric B factories, which establish for the first time CP violation in the B meson system.

  14. Game Play in Engineering Education Concept and Experimental Results*

    E-print Network

    Foss, Bjarne A.

    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 resources as having a positive learning effect. Keywords: dynamic simulation; games; engineering education

  15. Some Experimental Results with Tree Adjunct Grammar Guided Genetic

    E-print Network

    McKay, Robert Ian

    Some Experimental Results with Tree Adjunct Grammar Guided Genetic Programming N.X.Hoai 1 , R.I. Mc-adjunct grammar guided genetic programming (TAG3P) [5] is a grammar guided genetic programming system that uses context-free grammars along with tree-adjunct grammars as means to set language bias for the genetic

  16. Control of hysteresis: theory and experimental results , Ram Venkataraman

    E-print Network

    Iyer, Ram Venkataraman

    Control of hysteresis: theory and experimental results Xiaobo Tan , Ram Venkataraman , and P. S ABSTRACT Hysteresis in smart materials hinders the wider applicability of such materials in actuators. In this paper, a systematic approach for coping with hysteresis is presented. The method is illustrated through

  17. Design and experimental results for the S805 airfoil

    SciTech Connect

    Somers, D.M.

    1997-01-01

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

  18. Design and experimental results for the S809 airfoil

    SciTech Connect

    Somers, D.M.

    1997-01-01

    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.

  19. Experimental results of the MIT 17 GHz RF gun

    SciTech Connect

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

    1999-07-12

    We report on experimental results of a 17 GHz RF photocathode electron gun. This is the first photocathode electron gun to operate at a frequency above 2.856 GHz. The 1.5 cell, {pi}-mode, copper cavity was tested with 50 ns pulses from a 17.150 GHz klystron amplifier built by Haimson Research Corp. A Bragg filter was used at the RF gun to reduce the reflection of parasitic modes back into the klystron. Coupling hole theory in conjunction with cold test measurements was used to determine the field profile in the RF gun. The particle in cell code MAGIC was used to simulate the beam dynamics in the RF gun. With power levels of 4 MW, the on axis electric field at the cathode exceeds 300 MV/m, corresponding to an average accelerating gradient of 200 MV/m over the first half cell of the gun. Breakdown was observed at power levels above 5 MW. Electron bunches were produced by 20 {mu}J, 1 ps UV laser pulses impinging on the RF gun copper photocathode and were measured with a Faraday cup to have up to 0.1 nC of charge. This corresponds to a peak current of about 100 A, and a density at the cathode of 8.8 kA/cm{sup 2}. Multiple output electron bunches were obtained for multiple laser pulses incident on the cathode. Phase scans of laser induced electron emission reveal an overall phase stability of better than {+-}20 deg., corresponding to {+-}3 ps synchronization of the laser pulses to the phase of the microwave field. A Browne-Buechner magnetic spectrometer indicated that the RF gun generated 1 MeV electrons with a single shot rms energy spread of less than 2.5%, in good agreement with theoretical predictions.

  20. Experimental results of the MIT 17 GHz RF gun

    SciTech Connect

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

    1999-07-01

    We report on experimental results of a 17 GHz RF photocathode electron gun. This is the first photocathode electron gun to operate at a frequency above 2.856 GHz. The 1.5 cell, {pi}-mode, copper cavity was tested with 50 ns pulses from a 17.150 GHz klystron amplifier built by Haimson Research Corp. A Bragg filter was used at the RF gun to reduce the reflection of parasitic modes back into the klystron. Coupling hole theory in conjunction with cold test measurements was used to determine the field profile in the RF gun. The particle in cell code MAGIC was used to simulate the beam dynamics in the RF gun. With power levels of 4 MW, the on axis electric field at the cathode exceeds 300 MV/m, corresponding to an average accelerating gradient of 200 MV/m over the first half cell of the gun. Breakdown was observed at power levels above 5 MW. Electron bunches were produced by 20 {mu}J, 1 ps UV laser pulses impinging on the RF gun copper photocathode and were measured with a Faraday cup to have up to 0.1 nC of charge. This corresponds to a peak current of about 100 A, and a density at the cathode of 8.8 kA/cm{sup 2}. Multiple output electron bunches were obtained for multiple laser pulses incident on the cathode. Phase scans of laser induced electron emission reveal an overall phase stability of better than {plus_minus}20{degree}, corresponding to {plus_minus}3 ps synchronization of the laser pulses to the phase of the microwave field. A Browne-Buechner magnetic spectrometer indicated that the RF gun generated 1 MeV electrons with a single shot rms energy spread of less than 2.5{percent}, in good agreement with theoretical predictions. {copyright} {ital 1999 American Institute of Physics.}

  1. Experimental results for a hypersonic nozzle/afterbody flow field

    NASA Technical Reports Server (NTRS)

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

    1995-01-01

    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.

  2. On the interpretation of the results of the experimental test of the Askar'yan effect

    NASA Astrophysics Data System (ADS)

    Filonenko, A. D.

    2009-06-01

    The effect of the environment on the results of measuring the radio radiation spectrum is considered in the experimental simulation of the cascade shower by a high-energy ?-ray beam in a dense medium. The calculation shows that the character of the measured energy spectrum depends on the location of the receiving antenna with respect to the shower axis.

  3. Proteins in electric fields and pressure fields: experimental results.

    PubMed

    Fidy, J; Balog, E; Köhler, M

    1998-08-18

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

  4. Experimental results on mass-thickness distribution in spacecraft equipment

    NASA Technical Reports Server (NTRS)

    Bodin, V. V.; Repin, N. N.; Sakovich, V. A.; Sakharov, V. M.

    1978-01-01

    A technique is described for evaluating the shielding properties of spacecraft equipment with respect to cosmic radiation. A gamma-ray source is used in conjunction with a scintillation detector to determine mass-thickness distribution both in plane geometry for equipment units, and in spherical geometry for given points within the spacecraft. Equations are presented for calculating mass-thickness distribution functions, and the results are compared with experimental measurements.

  5. Modeling and experimental result analysis for high-power VECSELs

    NASA Astrophysics Data System (ADS)

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

    2003-06-01

    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, spatially resolved in both the radial and longitudinal directions, with temperature and carrier density dependent pump absorption. The radial distribution of the refractive index and gain due to temperature variation are computed. Thermal managment issues, highlighted by the experimental data, are discussed. Experimental results indicate a critical dependence of the input power, at which thermal roll-over occurs, on the thermal resistance of the device. This requires minimization of the substrate thickness and optimization of the design and placement of the heatsink. Dependence of the model results on the radiative and non-radiative carrier recombination lifetimes and cavity losses are evaluated.

  6. Mechanical properties of triaxially braided composites: Experimental and analytical results

    NASA Technical Reports Server (NTRS)

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

    1992-01-01

    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.

  7. Higgs decay H ? ??: New theoretical results and possible experimental implications

    NASA Astrophysics Data System (ADS)

    Gastmans, R.; Wu, Sau Lan; Wu, Tai Tsun

    2015-11-01

    The contribution of one W loop to the decay of the Higgs particle into two gammas is recalculated. Since this matrix element is finite in the standard model, it should be calculated in a straightforward way without artifacts such as regularization or ghosts. The result of the present calculation differs from the previous one, giving a Higgs decay rate smaller by a factor of 2 in the mass range of physical interest. In view of the results from the ATLAS Collaboration and the CMS Collaboration, this leads to possible far-reaching experimental consequences.

  8. An experimentally validated electromagnetic energy harvester

    NASA Astrophysics Data System (ADS)

    Elvin, Niell G.; Elvin, Alex A.

    2011-05-01

    A relatively simple method for determining the electromechanical parameters of electromagnetic energy harvesters are presented in this paper. The optimal power generated through a load resistor at both off-resonance and resonance is derived analytically. The experimentally measured performance of a rudimentary electromechanical energy harvester using a rare-earth magnet shows good agreement with the results from the model. The parasitic generator coil resistance can have a profound effect on the overall performance of an electromagnetic generator by essentially acting to degrade the effective coupling coefficient. Data from the setup electromagnetic generator shows normalized power densities of 1.7 ?W/[(m/s 2) 2 cm 3] operating at a resonance frequency of 112.25 Hz. This power density is comparable with other electromagnetic devices of the same volume operating at these frequencies. The power output of the presented electromagnetic generator is comparable to equivalent piezoelectric generators.

  9. Design and experimental results for the S814 airfoil

    SciTech Connect

    Somers, D.M.

    1997-01-01

    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.

  10. Correlation of analytical and experimental hot structure vibration results

    NASA Technical Reports Server (NTRS)

    Kehoe, Michael W.; Deaton, Vivian C.

    1993-01-01

    High surface temperatures and temperature gradients can affect the vibratory characteristics and stability of aircraft structures. Aircraft designers are relying more on finite-element model analysis methods to ensure sufficient vehicle structural dynamic stability throughout the desired flight envelope. Analysis codes that predict these thermal effects must be correlated and verified with experimental data. Experimental modal data for aluminum, titanium, and fiberglass plates heated at uniform, nonuniform, and transient heating conditions are presented. The data show the effect of heat on each plate's modal characteristics, a comparison of predicted and measured plate vibration frequencies, the measured modal damping, and the effect of modeling material property changes and thermal stresses on the accuracy of the analytical results at nonuniform and transient heating conditions.

  11. Experimental High Energy Neutrino Astrophysics

    SciTech Connect

    Distefano, Carla

    2005-10-12

    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.

  12. Sheet Hydroforming Process Numerical Model Improvement Through Experimental Results Analysis

    NASA Astrophysics Data System (ADS)

    Gabriele, Papadia; Antonio, Del Prete; Alfredo, Anglani

    2010-06-01

    The increasing application of numerical simulation in metal forming field has helped engineers to solve problems one after another to manufacture a qualified formed product reducing the required time [1]. Accurate simulation results are fundamental for the tooling and the product designs. The wide application of numerical simulation is encouraging the development of highly accurate simulation procedures to meet industrial requirements. Many factors can influence the final simulation results and many studies have been carried out about materials [2], yield criteria [3] and plastic deformation [4,5], process parameters [6] and their optimization. In order to develop a reliable hydromechanical deep drawing (HDD) numerical model the authors have been worked out specific activities based on the evaluation of the effective stiffness of the blankholder structure [7]. In this paper after an appropriate tuning phase of the blankholder force distribution, the experimental activity has been taken into account to improve the accuracy of the numerical model. In the first phase, the effective capability of the blankholder structure to transfer the applied load given by hydraulic actuators to the blank has been explored. This phase ended with the definition of an appropriate subdivision of the blankholder active surface in order to take into account the effective pressure map obtained for the given loads configuration. In the second phase the numerical results obtained with the developed subdivision have been compared with the experimental data of the studied model. The numerical model has been then improved, finding the best solution for the blankholder force distribution.

  13. Experimental water vapor permeability results for common wall materials

    SciTech Connect

    Sipes, J.M.; Hosni, M.H.

    2000-07-01

    This paper presents the experimental water vapor permeability results for gypsum board, latex paint, permeable vinyl wallpaper, vinyl wallpaper, and elastomeric stucco. For each material, a series of modified cup tests was conducted, and the material water vapor permeability was obtained as a function of relative humidity across the specimen. This test method was a modification of the ASTM Standard Test Method E 96-93. The permeability values for the materials tested in this study were compared to the limited available data from literature and were found to be in good agreement.

  14. Experimental Results on Flavour Oscillations and CP-Violation

    E-print Network

    P. K. Behera

    2009-01-11

    30 years ago M. Kobayashi and T. Masakawa (won the Nobel Prize in physics 2008 for their famous t heory), gave a theory to explaining CP violation. This theory predicted that large CP violation wou ld be observed in B mesons . In the last 10 years, Both the B-factories (babar at Stanford Linear Accelerator Center, USA and Belle at KEK, Japan) have observed large CP violation as predicted by th e KM mechanism. The ground breaking experimental results of Flavor Oscillation and CP violation in B and D mesons are summarized and compared with the Standard Model expectations.

  15. Large aperture spatial heterodyne imaging spectrometer: Principle and experimental results

    NASA Astrophysics Data System (ADS)

    Xiangli, Bin; Cai, Qisheng; Du, Shusong

    2015-12-01

    A large aperture spatial heterodyne imaging spectrometer (LASHIS) is proposed. It is a kind of pushbroom Fourier transform ultraspectral imager with no moving parts. This imaging spectrometer, based on a Sagnac lateral shearing interferometer combined with a pair of gratings, has the advantages of high spectral resolution, high throughput and robustness. The principle of LASHIS and its spectral retrieval method are introduced. The processing chain to convert raw images to ultraspectral datacube is also described. Experimental results demonstrate the high resolving power of LASHIS with the emission spectrum of a low pressure sodium lamp.

  16. Experimental and simulational result multipactors in 112 MHz QWR injector

    SciTech Connect

    Xin, T.; Ben-Zvi, I.; Belomestnykh, S.; Brutus, J. C.; Skaritka, J.; Wu, Q.; Xiao, B.

    2015-05-03

    The first RF commissioning of 112 MHz QWR superconducting electron gun was done in late 2014. The coaxial Fundamental Power Coupler (FPC) and Cathode Stalk (stalk) were installed and tested for the first time. During this experiment, we observed several multipacting barriers at different gun voltage levels. The simulation work was done within the same range. The comparison between the experimental observation and the simulation results are presented in this paper. The observations during the test are consisted with the simulation predictions. We were able to overcome most of the multipacting barriers and reach 1.8 MV gun voltage under pulsed mode after several round of conditioning processes.

  17. Experimental determination of stress variation threshold resulted in earthquake triggering

    NASA Astrophysics Data System (ADS)

    Novikova, Elena; Novikov, Victor; Okunev, Vladimir; Klyuchkin, Vadim

    2014-05-01

    There are many field observations of earthquake triggering by static and dynamic stress variations caused by impact of distant strong earthquakes, underground chemical and nuclear explosions, solar-lunar earth tides, strong variations of atmospheric pressure etc., as well as by electric current injection into the Earth crust. It is supposed that the external impacts on the earthquake source result in exceeding the threshold stress and earthquake triggering. Nevertheless, the mechanisms of the earthquake triggering phenomena is not clear, and the problem of determination of stress variation threshold resulted in initiation of seismic events is very important. At present, based on analysis of field observations of dynamic triggering of earthquakes (by wave train from distant strong earthquakes) performed for various regions, including the USA, Japan, China, Greece, etc. it is considered that the triggering threshold of stress variations is about of 500 kPa. An experimental study at the spring-slider system was carried out for detailed study of behavior of fault area under near-to-failure state and experimental triggering impacts, as well as for determination of the threshold variation of normal stress in the fault gauge resulted in earthquake (slip) triggering. The spring-slider system provides a spring loading rate of 0.001 to 0.02 mm/s. The travelling block of dimensions 250x120x65 mm is connected with electromechanical drive via the spring with 9.5 N/mm spring constant. The normal stress of the travelling block is up to 30 kPa. For determination of the triggering threshold of normal stress variations the electromagnetic system was activated by control system at the level of 0.98-0.99 critical (fault failure) shear stress, which provided reducing the normal stress (by 0.001% to 0.1%) in the form of rectangular pulses of 0.5 to 5.0 s duration generated in time interval of 20 to 40 s. The level of stress variation impact resulted in the slip of travelling block (with stable time delay after the pulse initiation) is considered as the threshold for the present experimental "stick-slip" system. The measured triggering threshold of normal stress variations in the fault simulator is 0.05% to 0.10%. An implication of obtained threshold values for various earthquake mechanisms is discussed.

  18. Interpretation of PISCES -- A RF antenna system experimental results

    SciTech Connect

    Rothweil, D.A.; Phelps, D.A.; Doerner, R.

    1995-10-01

    The paper describes experimental data from rf coupling experiments using one to four coil antenna arrays that encircle a linear magnetized plasma column. Experimental results using single turn coil that produce symmetric (i.e. m = 0), dipole (m = 1), and radial rf magnetic fields for coupling to ion waves are compared. By operating without a Faraday shield, it was observed for the first time that the plasma resistive load seen by these different antenna types tends to increase with the number of turns to at least the second power. A four-turn m = 0 coil experienced a record 3--5 {Omega} loading, corresponding to over 90% power coupling to the plasma. A four-turn m = 1 coil experienced up to 1--1.5 {Omega} loading, also higher than previous observations. First time observations using a two coil array of m = 0 coil are also reported. As predicted, the loading decreases with increasing phase between coil from 0{degree} to 180{degree}. Experiments using four coil arrays were difficult to optimize and interpret primarily due to complexity of the manual tuning. To facilitate this optimization in the future, a proposed feedback control system that automatically matches load variations between 0.2 and 10 {Omega} is described.

  19. Physical mechanism of comet outbursts - An experimental result

    NASA Technical Reports Server (NTRS)

    Hartmann, William K.

    1993-01-01

    Attention is given to an experimental investigation of the physical mechanism of comet outbursts which is consistent with the general picture of mantle presence on comets and clarifies the relation of mantles to eruptive activity. The experiment and closeup observation of Comet P/Halley suggest a result different from most mathematical models in that the release of gas pressure does not occur only from uniform gas flow out of the entire surface. In some active comets near perihelion within a few AU of the sun, gas production rates and disturbance of the surface may be so high that the outflow is nearly continuous, with the regolith being entirely stripped away, as in many of the models. The present model provides a cyclic eruption and recharge mechanism which is lacking in most other models.

  20. Experimental results to study astrophysical plasma jets using Intense Lasers

    NASA Astrophysics Data System (ADS)

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

    2009-08-01

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

  1. Solving and Learning Soft Temporal Constraints: Experimental Setting and Results

    NASA Technical Reports Server (NTRS)

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

    2002-01-01

    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.

  2. Percutaneous removal of ureteral calculi: clinical and experimental results.

    PubMed

    Hunter, D W; Castaneda-Zuniga, W R; Young, A T; Cardella, J; Lund, G; Rysavy, J A; Hulbert, J; Lange, P; Reedy, P; Amplatz, K

    1985-08-01

    Between May 1983 and October 1984, 51 patients who had 68 ureteral stones underwent treatment at the University of Minnesota. All 68 stones were removed successfully using percutaneous techniques. The 100% success rate is a great improvement over previous results at our institution. The primary factors appear to be the development of the retrograde-flush technique, familiarity with and access to a wider range of methods, and the increasing use of the retrograde ureterorenoscope to see stones in the lower ureter. The average patient was a 45-year-old man who had no other medical problems. The average hospital stay was 6.8 days. Experimental studies with dogs indicate that injection rates of up to 30 ml/sec of contrast material through a retrograde catheter in the ureter are safe if a vent is present in the upper collecting system. PMID:4011895

  3. Beta decay and the origins of biological chirality - Experimental results

    NASA Technical Reports Server (NTRS)

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

    1982-01-01

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

  4. ['Methadone substitution therapy and driving'. Results of an experimental study].

    PubMed

    Dittert, S; Naber, D; Soyka, M

    1999-05-01

    The aim of our experimental study was to gain informations and data on the driving ability of patients undergoing a methadone substitution programme as well as to explore the influence of an HIV infection. 28 patients, five of them HIV-positive, were compared to a control group equal in age, sex and education. For the traffic relevant tests the methadone patients showed significantly reduced performance. Six of the methadone patients passed the tests in a way regarded to have sufficient driving skills. We were unable to prove an influence of HIV infection on driving skills when lacking relevant somatic and neuropsychiatric symptoms. There was no significant correlation between the test results and patients age or dose of medication. We conclude that in general methadone substitution does not implicate driving inability although the majority of our patients showed some reduction of their psychomotoric skills. PMID:10407842

  5. Experimental results of a single emittance compensation solenoidal magnet

    SciTech Connect

    Palmer, D.T.; Miller, R.H.; Wang, X.J.; Ben-Zvi, I.; Skaritka, J.

    1997-07-01

    A new iron dominated single emittance compensation solenoidal magnet was designed to be integrated with the BNL/SLAC/UCLA 1.6 cell S-Band Photocathode rf Gun. This emittance compensated photoinjector is now in operation at the Brookhaven Accelerator Test Facility. It has produced a 0.329 {+-} 0.012 pC, {tau}{sub 95%} = 10.9 psec electron bunches with a normalized rms transverse emittance of {epsilon}{sub n,rms} = 1.17 {+-} 0.16 {pi} mm mrad. POISSON field maps were used with PARMELA to optimize the emittance compensation solenoidal magnet design. Magnetic field measurements show that at the cathode plane B{sub z} {le} 10 G for a peak magnetic field of B{sub z,max} = 3 kG. Which is in agreement with POISSON simulation. A single emittance compensation solenoidal magnet will produces an initial angular momentum of the electron bunch that manifests itself in a initial magnetic emittance term that cannot be eliminated. This magnetic emittance {epsilon}{sub n,rms}{sup mag} scales as 0.010 {pi} mm mrad/G as the cathode, which is in agreement with PARMELA simulations. Experimental beam dynamics results are presented that shows relative angular rotation and spot size as a function of cathode magnetic field. These results are compared to theory.

  6. Experimental evidence that evolutionarily diverse assemblages result in higher productivity

    PubMed Central

    Cadotte, Marc W.

    2013-01-01

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

  7. Experimental Results of Integrated Refrigeration and Storage System Testing

    NASA Technical Reports Server (NTRS)

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

    2009-01-01

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

  8. Experimental subarachnoid haemorrhage results in multifocal axonal injury.

    PubMed

    Kummer, Terrance T; Magnoni, Sandra; MacDonald, Christine L; Dikranian, Krikor; Milner, Eric; Sorrell, James; Conte, Valeria; Benetatos, Joey J; Zipfel, Gregory J; Brody, David L

    2015-09-01

    The great majority of acute brain injury results from trauma or from disorders of the cerebrovasculature, i.e. ischaemic stroke or haemorrhage. These injuries are characterized by an initial insult that triggers a cascade of injurious cellular processes. The nature of these processes in spontaneous intracranial haemorrhage is poorly understood. Subarachnoid haemorrhage, a particularly deadly form of intracranial haemorrhage, shares key pathophysiological features with traumatic brain injury including exposure to a sudden pressure pulse. Here we provide evidence that axonal injury, a signature characteristic of traumatic brain injury, is also a prominent feature of experimental subarachnoid haemorrhage. Using histological markers of membrane disruption and cytoskeletal injury validated in analyses of traumatic brain injury, we show that axonal injury also occurs following subarachnoid haemorrhage in an animal model. Consistent with the higher prevalence of global as opposed to focal deficits after subarachnoid haemorrhage and traumatic brain injury in humans, axonal injury in this model is observed in a multifocal pattern not limited to the immediate vicinity of the ruptured artery. Ultrastructural analysis further reveals characteristic axonal membrane and cytoskeletal changes similar to those associated with traumatic axonal injury. Diffusion tensor imaging, a translational imaging technique previously validated in traumatic axonal injury, from these same specimens demonstrates decrements in anisotropy that correlate with histological axonal injury and functional outcomes. These radiological indicators identify a fibre orientation-dependent gradient of axonal injury consistent with a barotraumatic mechanism. Although traumatic and haemorrhagic acute brain injury are generally considered separately, these data suggest that a signature pathology of traumatic brain injury-axonal injury-is also a functionally significant feature of subarachnoid haemorrhage, raising the prospect of common diagnostic, prognostic, and therapeutic approaches to these conditions. PMID:26115676

  9. New experimental results for a vector boson A

    NASA Astrophysics Data System (ADS)

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

    2012-03-01

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

  10. Alkali Metal Backup Cooling for Stirling Systems - Experimental Results

    NASA Technical Reports Server (NTRS)

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

    2013-01-01

    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.

  11. Alkali Metal Backup Cooling for Stirling Systems - Experimental Results

    NASA Technical Reports Server (NTRS)

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

    2013-01-01

    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.

  12. CP Violation in B Meson Decays: Experimental Results

    SciTech Connect

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

    2005-08-30

    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.

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

    SciTech Connect

    Zayarnaya, I. S.

    2008-02-15

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

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

    SciTech Connect

    Kato, K.G.; Crouch, D.D.; Sar, D.R.; Speciale, R.A.; Carlsten, B.E.; Fazio, M.V.; Haynes, W.B.; Stringfield, R.M.

    1994-12-31

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

  15. Applying computational methods to interpret experimental results in tribology and enantioselective catalysis

    NASA Astrophysics Data System (ADS)

    Garvey, Michael T.

    Computational methods are rapidly becoming a mainstay in the field of chemistry. Advances in computational methods (both theory and implementation), increasing availability of computational resources and the advancement of parallel computing are some of the major forces driving this trend. It is now possible to perform density functional theory (DFT) calculations with chemical accuracy for model systems that can be interrogated experimentally. This allows computational methods to supplement or complement experimental methods. There are even cases where DFT calculations can give insight into processes and interactions that cannot be interrogated directly by current experimental methods. This work presents several examples of the application of computational methods to the interpretation and analysis of experimentally obtained results. First, triobological systems were investigated primarily with full-potential linearized augmented plane wave (FLAPW) method DFT calculations. Second, small organic molecules adsorbed on Pd(111) were studied using projector-augmented wave (PAW) method DFT calculations and scanning tunneling microscopy (STM) image simulations to investigate molecular interactions involved in enantioselective heterogeneous catalysis. A method for method for calculating pressure-dependent shear properties of model boundary-layer lubricants is demonstrated. The calculated values are compared with experimentally obtained results. For the case of methyl pyruvate adsorbed on Pd(111), DFT-calculated adsorption energies and structures are used along with STM simulations to identify species observed by STM imaging. A previously unobserved enol species is discovered to be present along with the expected keto species. The information about methyl pyruvate species on Pd(111) is combined with previously published studies of S-alpha-(1-naphthyl)-ethylamine (NEA) to understand the nature of their interaction upon coadsorption on Pd(111). DFT calculated structures and energies are used to identify potential docking complexes and STM simulations are compared to the experimental STM images.

  16. Experimental Studies of Ion Beam Neutralization: Preliminary Results

    SciTech Connect

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

    2011-05-20

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

  17. Laser ablation of a turbid medium: Modeling and experimental results

    SciTech Connect

    Brygo, F.; Semerok, A.; Weulersse, J.-M.; Thro, P.-Y.; Oltra, R.

    2006-08-01

    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.

  18. Experimental results for a microscale ethanol vapor jet ejector

    NASA Astrophysics Data System (ADS)

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

    2010-04-01

    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.

  19. Electromagnetic structure of the deuteron: review of recent theoretical and experimental results

    E-print Network

    Franz Gross

    2002-09-26

    This talk reviews recent theoretical and experimental results for elastic electron deuteron scattering (yielding the deuteron form factors), threshold electrodisintegration ($e+d\\to e'+p+n$ where the mass of the final $np$ pair, $W$, is only a few MeV above the threshold value of $m_p+m_n$), and high energy deuteron photodisintegration ($\\gamma+d\\to p+n$). The talk is based on the complete reviews of Refs. [GVO,S,GG], with a few new results not previously reported.

  20. Fracture mechanics analysis of composite microcracking - Experimental results in fatigue

    NASA Technical Reports Server (NTRS)

    Nairn, J. A.; Liu, S.

    1990-01-01

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

  1. Waste glass corrosion modeling: Comparison with experimental results

    SciTech Connect

    Bourcier, W.L.

    1993-11-01

    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.

  2. Experimental results with hydrogen fueled internal combustion engines

    NASA Technical Reports Server (NTRS)

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

    1975-01-01

    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.

  3. Vaporization inside a mini microfin tube: experimental results and modeling

    NASA Astrophysics Data System (ADS)

    Diani, A.; Rossetto, L.

    2015-11-01

    This paper proposes a comparison among the common R134a and the extremely low GWP refrigerant R1234yf during vaporization inside a mini microfin tube. This microfin tube has an internal diameter of 2.4 mm, it has 40 fins, with a fin height of 0.12 mm. Due to the high heat transfer coefficients shown by this tube, this technology can lead to a refrigerant charge reduction. Tests were run in the Heat Transfer in Micro Geometries Lab of the Dipartimento di Ingegneria Industriale of the Università di Padova. Mass velocities range between 375 and 940 kg m-2 s-1, heat fluxes from 10 to 50 kW m-2, vapour qualities from 0.10 to 0.99, at a saturation temperature of 30°C. The comparison among the two fluids is proposed at the same operating conditions, in order to highlight the heat transfer and pressure drop differences among the two refrigerants. In addition, two correlations are proposed to estimate the heat transfer coefficient and frictional pressure drop during refrigerant flow boiling inside mini microfin tubes. These correlations well predict the experimental values, and thus they can be used as a useful tool to design evaporators based on these mini microfin tubes.

  4. Modeling of rock friction 1. Experimental results and constitutive equations

    USGS Publications Warehouse

    Dieterich, J.H.

    1979-01-01

    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.

  5. Construction of a WMR for Trajectory Tracking Control: Experimental Results

    PubMed Central

    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

    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

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

    PubMed

    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

    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

  7. EXPERIMENTAL RESULTS FROM A MICROWAVE CAVITY BEAM POSITION MONITOR.

    SciTech Connect

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

    1999-03-29

    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.

  8. Effects of imperfect dynamic clamp: computational and experimental results.

    PubMed

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

    2008-04-30

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

  9. [Experimental and theoretical high energy physics program

    SciTech Connect

    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

    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)

  10. Fuel Canister Stress Corrosion Cracking Susceptibility Experimental Results

    SciTech Connect

    Colleen Shelton-Davis

    2003-03-01

    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.

  11. Experimental results and modeling of a dynamic hohlraum on SATURN

    SciTech Connect

    Derzon, M.S.; Allshouse, G.O.; Deeney, C.; Leeper, R.J.; Nash, T.J.; Matuska, W.; Peterson, D.L.; MacFarlane, J.J.; Ryutov, D.D.

    1998-06-01

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

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

    ERIC Educational Resources Information Center

    Johnson, Eric R.; Alter, Paula

    1989-01-01

    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)

  13. Joint Soviet-American experiment on hypokinesia: Experimental results

    NASA Technical Reports Server (NTRS)

    Burovskiy, N. N.

    1979-01-01

    Comprehensive results are reported from the Soviet portion of a joint Soviet-American experiment involving hypokinesia. The main emphases are on chemical analyses of blood and urine, functional tests, and examination of the cardiovascular system by electrocardiography, echocardiography, and plethysmography.

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

    NASA Astrophysics Data System (ADS)

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

    2014-04-01

    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.

  15. Delaminations in composite plates under transverse static loads - Experimental results

    NASA Technical Reports Server (NTRS)

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

    1992-01-01

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

  16. Overview of Recent DIII-D Experimental Results

    NASA Astrophysics Data System (ADS)

    Fenstermacher, M. E.; DIII-D Team

    2014-10-01

    Recent DIII-D experiments have added to the ITER physics basis and to physics understanding for extrapolation to future devices. Physics mechanisms contributing to resonant magnetic perturbation ELM suppression and QH-mode were identified. The QH-mode operating space was extended to ITER-relevant parameters and predicted Super-H mode performance was observed at high shaping. Upgraded divertor Thomson data was combined with edge modeling to identify the core density limit at divertor detachment. Pedestal studies were done to determine the role of ?*, Zeff and kinetic ballooning mode instabilities in controlling pedestal structure. Injection of massive high-Z gas dissipates magnetic and kinetic energy of runaway electron beams. 3D magnetics data validate several linear MHD codes, including ability to predict neoclassical tearing viscosity torque. Feedback control of applied 3D fields facilitates access to increased ?N values above the no-wall limit. The effect of test blanket module (TBM) fields on fast ion losses and momentum transport, and partial correction of TBM fields at high ? was achieved. Density gradient driven trapped electron modes and core ne peaking were controlled by electron cyclotron heating suggesting a possible burn control technique. Work supported by the US DOE under DE-FC02-04ER54698 and DE-AC52-07NA27344.

  17. Quark-Gluon Plasma: from lattice simulations to experimental results

    NASA Astrophysics Data System (ADS)

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

    2014-07-01

    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.

  18. Delaminations in composite plates under transverse impact loads - Experimental results

    NASA Technical Reports Server (NTRS)

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

    1993-01-01

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

  19. Experimental test accelerator: description and results of initial experiments

    SciTech Connect

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

    1980-06-02

    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.

  20. Experimental Results of Guided Wave Travel Time Tomography

    NASA Astrophysics Data System (ADS)

    Volker, Arno; Bloom, Joost

    2011-06-01

    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.

  1. Acceleration and torque feedback for robotic control - Experimental results

    NASA Technical Reports Server (NTRS)

    Mclnroy, John E.; Saridis, George N.

    1990-01-01

    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.

  2. IP voice over ATM satellite: experimental results over satellite channels

    NASA Astrophysics Data System (ADS)

    Saraf, Koroush A.; Butts, Norman P.

    1999-01-01

    IP telephony, a new technology to provide voice communication over traditional data networks, has the potential to revolutionize telephone communication within the modern enterprise. This innovation uses packetization techniques to carry voice conversations over IP networks. This packet switched technology promises new integrated services, and lower cost long-distance communication compared to traditional circuit switched telephone networks. Future satellites will need to carry IP traffic efficiently in order to stay competitive in servicing the global data- networking and global telephony infrastructure. However, the effects of Voice over IP over switched satellite channels have not been investigated in detail. To fully understand the effects of satellite channels on Voice over IP quality; several experiments were conducted at Lockheed Martin Telecommunications' Satellite Integration Lab. The result of those experiments along with suggested improvements for voice communication over satellite are presented in this document. First, a detailed introduction of IP telephony as a suitable technology for voice communication over future satellites is presented. This is followed by procedures for the experiments, along with results and strategies. In conclusion we hope that these capability demonstrations will alleviate any uncertainty regarding the applicability of this technology to satellite networks.

  3. Microgravity Fluid Separation Physics: Experimental and Analytical Results

    NASA Technical Reports Server (NTRS)

    Shoemaker, J. Michael; Schrage, Dean S.

    1997-01-01

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2007-12-01

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

  5. Experimental results: Pilot plant calcine dissolution and liquid feed stability

    SciTech Connect

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

    1995-02-01

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

  6. Longitudinal variation of the equatorial ionosphere: Modeling and experimental results

    NASA Astrophysics Data System (ADS)

    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

    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.

  7. Impact ejecta dynamics in an atmosphere - Experimental results and extrapolations

    NASA Technical Reports Server (NTRS)

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

    1982-01-01

    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.

  8. Bridge Testing With Ground-Based Interferometric Radar: Experimental Results

    SciTech Connect

    Chiara, P.; Morelli, A.

    2010-05-28

    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.

  9. EXPERIMENTAL RESULTS OF THE NEPHELINE PHASE III STUDY

    SciTech Connect

    Fox, K.; Edwards, T.

    2009-11-09

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

  10. Selected problems in experimental intermediate energy physics

    SciTech Connect

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

    1990-09-01

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

  11. Alfven Wave Generation by a Rotating Magnetic Field Source: Theory, Modeling and Experimental Results

    NASA Astrophysics Data System (ADS)

    Sharma, A. S.; Karavaev, A. V.; Gumerov, N.; Shao, X.; Papadopoulos, K.; Gekelman, W.; Wang, Y.; Vincena, S.; Pribyl, P.

    2010-11-01

    Recent experiments conducted in the Large Plasma Device (LAPD) located at UCLA demonstrated efficient excitation of whistler and shear Alfven waves by a Rotating Magnetic Field (RMF) source. We present analytical theory, computational modeling and experimental results of the shear Alfven wave excitation by RMF source created by a phased orthogonal two-loop antenna in a plasma. An analytical theory and simulations using a three-dimensional cold two-fluid model of Alfven wave excitation were developed and compared with experiments. These comparisons show good agreement on linear shear Alfven wave properties, namely, spatio-temporal wave structure, dispersion relation, and the dependence of wave magnitude on the wave frequency. From the simulations it was found that the energy of the Alfven wave generated by the rotating magnetic field source is distributed among the kinetic energies of ions and electrons and the electromagnetic energy of the wave. The wave magnetic field power calculated from the experimental data and using a fluid model agrees within ˜1 percent. The RMF source is thus very efficient in generating shear Alfven waves. Work supported by ONR MURI grant.

  12. Alfven Wave Generation by a Rotating Magnetic Field Source: Theory, Modeling and Experimental Results

    NASA Astrophysics Data System (ADS)

    Shao, X.; Karavaev, A. V.; Gumerov, N.; Sharma, A. S.; Papadopoulos, K.; Gekelman, W. N.; Wang, Y.; Vincena, S. T.; Pribyl, P.

    2010-12-01

    Recent experiments conducted in the Large Plasma Device (LAPD) located at UCLA demonstrated efficient excitation of whistler and shear Alfven waves by a Rotating Magnetic Field (RMF) source. We present analytical theory, computational modeling and experimental results of the shear Alfven wave excitation by RMF source created by a phased orthogonal two-loop antenna in a plasma. An analytical theory and simulations using a three-dimensional cold two-fluid model of Alfven wave excitation were developed and compared with experiments. These comparisons show good agreement on linear shear Alfven wave properties, namely, spatio-temporal wave structure, dispersion relation, and the dependence of wave magnitude on the wave frequency. From the simulations it was found that the energy of the Alfven wave generated by the rotating magnetic field source is distributed among the kinetic energies of ions and electrons and the electromagnetic energy of the wave. The wave magnetic field power calculated from the experimental data and using a fluid model agrees within 1 percent. The RMF source is thus very efficient in generating shear Alfven waves. Work supported by ONR MURI grant.

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

    E-print Network

    Srinivasan, Palanivel Rajan

    2000-01-01

    to represent twenty different laboratory experiments. The results of these models are compared with results available from extensive experimental dynamic testing on a geotechnical centrifuge. Though the various results from the finite element analysis...

  14. 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

  15. Preliminary experimental results of tungsten wire-array Z-pinches on primary test stand

    NASA Astrophysics Data System (ADS)

    Huang, Xian-Bin; Zhou, Shao-Tong; Dan, Jia-Kun; Ren, Xiao-Dong; Wang, Kun-Lun; Zhang, Si-Qun; Li, Jing; Xu, Qiang; Cai, Hong-Chun; Duan, Shu-Chao; Ouyang, Kai; Chen, Guang-Hua; Ji, Ce; Wei, Bing; Feng, Shu-Ping; Wang, Meng; Xie, Wei-Ping; Deng, Jian-Jun; Zhou, Xiu-Wen; Yang, Yi

    2015-07-01

    The Primary Test Stand (PTS) developed at the China Academy of Engineering Physics is a 20 TW 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. Preliminary 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 13 mm to 30 mm, consisting of 132-300 tungsten wires with 5-10 ?m in diameter. Multiple diagnostics were fielded to characterize the x-ray radiation from wire-array Z pinches. The x-ray peak power (˜50 TW) and total radiated energy (˜500 kJ) were obtained from a single 20-mm-diam array with 80-ns stagnation time. The highest x-ray peak power up to 80 TW with 2.4 ns FWHM was achieved by using a nested array with 20-mm outer diameter, and the total x-ray energy from the nested array is comparable to that of single array. Implosion velocity estimated from the time-resolved image measurement exceeds 30 cm/?s. The detailed experimental results and other findings are presented and discussed.

  16. Uncalibrated Building Energy Simulation Modeling Results 

    E-print Network

    Ahmad, M.; Culp, C.H.

    2006-01-01

    &R RESEARCH OCTOBER 2006 1141 Uncalibrated Building Energy Simulation Modeling Results Mushtaq Ahmad Charles H. Culp, PhD, PE Associate Member ASHRAE Fellow ASHRAE Received June 23, 2005; accepted April 17, 2006 Uncalibrated simulations have provided useful... for calibrated simulation procedures and tools. Mushtaq Ahmad is a research engineering associate II in the Energy Systems Laboratory and Charles H. Culp is an associate professor in the Department of Architecture and associate director of the Energy Systems...

  17. Problem Definition and Motivation Existing solutions New fast algorithm Experimental Results Lempel-Ziv Factorization Revisited

    E-print Network

    Lonardi, Stefano

    Problem Definition and Motivation Existing solutions New fast algorithm Experimental Results Lempel Palermo, June 27th 2011 #12;Problem Definition and Motivation Existing solutions New fast algorithm Experimental Results Outline 1 Problem Definition and Motivation 2 Existing solutions 3 New fast algorithm 4

  18. CZT detectors used in different irradiation geometries: Simulations and experimental results

    SciTech Connect

    Fritz, Shannon G.; Shikhaliev, Polad M.

    2009-04-15

    The purpose of this work was to evaluate potential advantages and limitations of CZT detectors used in surface-on, edge-on, and tilted angle irradiation geometries. Simulations and experimental investigations of the energy spectrum measured by a CZT detector have been performed using different irradiation geometries of the CZT. Experiments were performed using a CZT detector with 10x10 mm{sup 2} size and 3 mm thickness. The detector was irradiated with collimated photon beams from Am-241 (59.5 keV) and Co-57 (122 keV). The edge-scan method was used to measure the detector response function in edge-on illumination mode. The tilted angle mode was investigated with the radiation beam directed to the detector surface at angles of 90 degree sign , 15 degree sign , and 10 degree sign . The Hecht formalism was used to simulate theoretical energy spectra. The parameters used for simulations were matched to experiment to compare experimental and theoretical results. The tilted angle CZT detector suppressed the tailing of the spectrum and provided an increase in peak-to-total ratio from 38% at 90 degree sign to 83% at 10 degree sign tilt angle for 122 keV radiation. The corresponding increase for 59 keV radiation was from 60% at 90 degree sign to 85% at 10 degree sign tilt angle. The edge-on CZT detector provided high energy resolution when the beam thickness was much smaller than the thickness of CZT. The FWHM resolution in edge-on illumination mode was 4.2% for 122 keV beam with 0.3 mm thickness, and rapidly deteriorated when the thickness of the beam was increased. The energy resolution of surface-on geometry suffered from strong tailing effect at photon energies higher than 60 keV. It is concluded that tilted angle CZT provides high energy resolution but it is limited to a 1D linear array configuration. The surface-on CZT provides 2D pixel arrays but suffers from tailing effect and charge build up. The edge-on CZT is considered suboptimal as it requires small beam thickness and also suffers from charge buildup.

  19. Inter-species extrapolation of skin heating resulting from millimeter wave irradiation: modeling and experimental results.

    PubMed

    Nelson, D A; Walters, T J; Ryan, K L; Emerton, K B; Hurt, W D; Ziriax, J M; Johnson, L R; Mason, P A

    2003-05-01

    This study reports measurements of the skin surface temperature elevations during localized irradiation (94 GHz) of three species: rat (irradiated on lower abdomen), rhesus monkey (posterior forelimb), and human (posterior forearm). Two exposure conditions were examined: prolonged, low power density microwaves (LPM) and short-term, high power density microwaves (HPM). Temperature histories were compared with calculations from a bio-heat transfer model. The mean peak surface temperature increase was approximately 7.0 degrees C for the short-term HPM exposures for all three species/locations, and 8.5 degrees C (monkey, human) to 10.5 degrees C (rat) for the longer-duration LPM exposures. The HPM temperature histories are in close agreement with a one-dimensional conduction heat transfer model with negligible blood flow. The LPM temperature histories were compared with calculations from the bio-heat model, evaluated for various (constant) blood flow rates. Results suggest a variable blood flow model, reflecting a dynamic thermoregulatory response, may be more suited to describing skin surface temperature response under long-duration MMW irradiation. PMID:12747480

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

    SciTech Connect

    Menapace, E.; Birattari, C.; Bonardi, M.L.; Groppi, F.; Morzenti, S.; Zona, C.

    2005-05-24

    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.

  1. 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

  2. An Experimental Evaluation of Duct-Mounted Relative Humidity Sensors: Part 2 – Accuracy Results 

    E-print Network

    Joshi, S.N.; Pate, M.B.; Nelson, R.M; House, J.H.; Klaasen, C.J.

    2005-01-01

    with permission of the copyright owner. Further reproduction prohibited without permission. An Experimental Evaluation of Duct-Mounted Relative Humidity Sensors: Part 2-Accuracy Results Joshi, Shailesh N;House, John M;Pate, Michael B;Klaassen, Curtis J...

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

    NASA Astrophysics Data System (ADS)

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

    2013-02-01

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

  4. Experimental study of energy conversion in the magnetic reconnection layer

    NASA Astrophysics Data System (ADS)

    Yamada, Masaaki

    2014-10-01

    Magnetic reconnection, in which magnetic field lines break and reconnect to change their topology, occurs throughout the universe: in solar flares, the earth's magnetosphere, star forming galaxies, and laboratory fusion plasmas. The essential feature of reconnection is that it energizes plasma particles by converting magnetic energy to particle energy; this process both accelerates and heats the plasma particles. Despite the recent advances of reconnection research, the exact mechanisms for bulk plasma heating, particle acceleration, and energy flow channels remain unresolved. In this work, the mechanisms responsible for the energization of plasma particles in the magnetic reconnection layer are investigated in the MRX device together with a quantitative evaluation of the conversion of magnetic energy to ions and electrons. A comprehensive analysis of the reconnection layer is made in terms of two-fluid physics based on the measurements of two-dimensional profiles of 1) electric potential, 2) flow vectors of electrons and ions, and 3) the electron temperature, Te and the ion temperature, Ti in the layer. It is experimentally verified that a saddle shaped electrostatic electric potential profile is formed in the reconnection plane. Ions are accelerated across the separatrices by the strong electrostatic field and enter the exhaust region where they become thermalized. Electron heating is observed to extend beyond the electron diffusion region, and non-classical heating mechanisms associated with high frequency fluctuations is found to play a role. Our quantitative analysis of the energy transport processes and energy inventory concludes that more than 50% of magnetic energy is converted to plasma particles, of which 2/3 transferred to ions and 1/3 to electrons. The results which demonstrate that conversion of magnetic energy occurs in a significantly larger region than theoretically considered before, are compared with the two-fluid simulations and the recent space measurements. Broader implication of the present results will be discussed. Supported by DOE, NASA and NSF. Collaborators; J. Yoo, J. Jara Almonte, H. Ji, R. Kulsrud, and C. Myers.

  5. Experimental Results for Temporally Overlapping Pulses from Quantel EverGreen 200 Laser

    NASA Technical Reports Server (NTRS)

    Watkins, A. Neal

    2013-01-01

    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.

  6. Synthesizing large-scale pyroclastic flows: Experimental design, scaling, and first results from PELE

    NASA Astrophysics Data System (ADS)

    Lube, G.; Breard, E. C. P.; Cronin, S. J.; Jones, J.

    2015-03-01

    Pyroclastic flow eruption large-scale experiment (PELE) is a large-scale facility for experimental studies of pyroclastic density currents (PDCs). It is used to generate high-energy currents involving 500-6500 m3 natural volcanic material and air that achieve velocities of 7-30 m s-1, flow thicknesses of 2-4.5 m, and runouts of >35 m. The experimental PDCs are synthesized by a controlled "eruption column collapse" of ash-lapilli suspensions onto an instrumented channel. The first set of experiments are documented here and used to elucidate the main flow regimes that influence PDC dynamic structure. Four phases are identified: (1) mixture acceleration during eruption column collapse, (2) column-slope impact, (3) PDC generation, and (4) ash cloud diffusion. The currents produced are fully turbulent flows and scale well to natural PDCs including small to large scales of turbulent transport. PELE is capable of generating short, pulsed, and sustained currents over periods of several tens of seconds, and dilute surge-like PDCs through to highly concentrated pyroclastic flow-like currents. The surge-like variants develop a basal <0.05 m thick regime of saltating/rolling particles and shifting sand waves, capped by a 2.5-4.5 m thick, turbulent suspension that grades upward to lower particle concentrations. Resulting deposits include stratified dunes, wavy and planar laminated beds, and thin ash cloud fall layers. Concentrated currents segregate into a dense basal underflow of <0.6 m thickness that remains aerated. This is capped by an upper ash cloud surge (1.5-3 m thick) with 100 to 10-4 vol % particles. Their deposits include stratified, massive, normally and reversely graded beds, lobate fronts, and laterally extensive veneer facies beyond channel margins.

  7. Transient Creep and Strain Energy Dissipation: An Experimental Perspective

    NASA Astrophysics Data System (ADS)

    Faul, Ulrich; Jackson, Ian

    2015-05-01

    Energy dissipation due to intrinsic attenuation occurs at elevated temperatures in rocks as a result of a range of processes. Examples where small-strain, transient deformation occurs are seismic waves, tidal deformation, and at longer timescales post-glacial rebound and far-field post-seismic deformation. Experiments at mantle temperatures and seismic frequencies show that grain boundary sliding is a key process that results in a broad absorption band, as indicated by seismic observations. Models of grain boundary sliding predict a smooth transition from elastic behavior through an anelastic regime toward viscous (Maxwell) behavior, consistent with experimental observations. Other mechanisms that may contribute to dissipation in Earth, at least locally, are dislocations and melt. Extrapolation of the laboratory data shows that first-order observations of planetary behavior and structure can be explained by the effects of temperature and pressure on transient creep properties, but that locally, additional mechanisms are required.

  8. Numerical and Experimental Investigation of Tidal Current Energy Extraction 

    E-print Network

    Sun, Xiaojing

    2008-01-01

    Numerical and experimental investigations of tidal current energy extraction have been conducted in this study. A laboratory-scale water flume was simulated using commercial computational fluid dynamics (CFD) code FLUENT. ...

  9. On the Design of LIL Tests for (Pseudo) Random Generators and Some Experimental Results

    E-print Network

    International Association for Cryptologic Research (IACR)

    . The experimental results show that for a sample size of 1000 sequences (2TB), the statistical distance between.001 at the sample size 1000. These results justify the importance of LIL testing techniques designed in this paper with counter modes (e.g., in Java Crypto Library and in NIST SP800-90A standards). Though security of hash

  10. A stereo triangulation system for structural identification: Analytical and experimental results

    NASA Technical Reports Server (NTRS)

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

    1988-01-01

    Identification of large space structures' distributed mass, stiffness, and energy dissipation characteristics poses formidable analytical, numerical, and implementation difficulties. Development of reliable on-orbit structural identification methods is important for implementing active vibration suppression concepts which are under widespread study in the large space structures community. Near the heart of the identification problem lies the necessity of making a large number of spatially distributed measurements of the structure's vibratory response and the associated force/moment inputs with sufficient spatial and frequency resolution. In the present paper, we discuss a method whereby tens of active or passive (retro-reflecting) targets on the structure are tracked simultaneously by the focal planes of two or more video cameras mounted on an adjacent platform. Triangulation (optical ray intersection) of the conjugate image centroids yield inertial trajectories of each target on the structure. Given the triangulated motion of the targets, we apply and extend methodology developed by Creamer, Junkins, and Juang to identify the frequencies, mode shapes, and updated estimates for the mass/stiffness/damping parameterization of the structure. The methodology is semi-automated, for example, the post experiment analysis of the video imagery to determine the inertial trajectories of the targets typically requires less than thirty minutes of real time. Using methodology discussed herein, the frequency response of a large number of points on the structure (where reflective targets are mounted) on the structure can be determined from optical measurements alone. For comparison purposes, we also utilize measurements from accelerometers and a calibrated impulse hammer. While our experimental work remains in a research stage of development, we have successfully tracked and stereo triangulated 20 targets (on a vibrating cantilevered grid structure) at a sample frequency of 200 HZ, and have established conclusively the feasibility and desirability of this approach. We discuss, in summary, recent advances in analog and digital video processing methodology, actuation methods, and bring them to bear on the structural identification problem. We include a brief discussion of our experimental hardware and some recent experimental results which support the practical feasibility of this structural vibration sensing approach.

  11. Dynamic characterization of composites with embedded shape memory alloys: Some experimental results

    SciTech Connect

    De Santis, S.; Trochu, F.; Ostiguy, G.; Sol, H.; DeVisscher, J.

    1995-10-01

    Composites with embedded Shape Memory Alloy (SMA) fibers are considered to be adaptive materials. The physical properties of these materials can be modified by applying certain stimuli through the fibers. These changes mainly concern stiffness and damping of the material and strongly modify the vibrational behavior of structures made of these materials. The design of smart structures incorporating adaptive materials, assumes precise knowledge of material as well as structure behavior. The paper explores two methods for obtaining a dynamic characterization of thin epoxy composites plates with embedded SMA fibers. The first method, experimental modal analysis, determines the modal parameters of the composite structure. The second method, based on natural frequency and modal damping ratio measurements, determines the complex engineering constants of the composite material. Results are obtained at room temperature for test plates with martensitic and austenitic (Cu/Zn/Al) fibers. Comparisons are made with respect to at est plate without fibers. Finally, a modal strain energy approach is used to numerically determine modal damping ratios of the test plates from the values of the complex engineering constants.

  12. First Experimental Results From the Princeton MagnetoRotational Instability (MRI) Experiment

    NASA Astrophysics Data System (ADS)

    Schartman, E.; Ji, H.; Cutler, R.; Burin, M. J.; Goodman, J.

    2006-10-01

    The inferred rate of angular momentum transport in accretion disks is too large to be explained by a molecular viscosity. Two sources of instability to drive turbulence have been proposed: the MRI and subcritical hydrodynamic instability. In the MRI, a weak magnetic field can use the angular velocity gradient as a source of free energy. In the subcritical case, finite amplitude disturbances are expected to allow access to non-linear instabilities. Recent experimental investigations have claimed to observe both mechanisms in the laboratory, but neither has been conclusively demonstrated. During the first year of operation, the Princeton MRI Experiment has been searching for conclusive evidence of these instabilities. The experiment is a Couette-Taylor apparatus which uses water or liquid Gallium alloy to generate rotating shear flows with linear stability properties analagous to astrophysical disks. In the purely hydrodynamic case we do not find evidence of angular momentum transport great enough to be astrophysically important. We will also present initial results of our search for the MRI using liquid Gallium as our working fluid.

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

    SciTech Connect

    Carcreff, Hubert; Cloute-Cazalaa, Veronique; Salmon, Laurent

    2012-08-15

    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)

  14. Trends in experimental high-energy physics

    SciTech Connect

    Sanford, T.W.L.

    1982-06-01

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

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

    PubMed

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

    2011-03-20

    Using experimental results and numerical simulations, two measuring concepts of the laser induced deflection (LID) technique are introduced and optimized for absolute thin film absorption measurements from deep ultraviolet to IR wavelengths. For transparent optical coatings, a particular probe beam deflection direction allows the absorption measurement with virtually no influence of the substrate absorption, yielding improved accuracy compared to the common techniques of separating bulk and coating absorption. For high-reflection coatings, where substrate absorption contributions are negligible, a different probe beam deflection is chosen to achieve a better signal-to-noise ratio. Various experimental results for the two different measurement concepts are presented. PMID:21460979

  16. Experimental and computational study of the mean energy of electrons backscattered from surface films

    SciTech Connect

    Dapor, Maurizio; Rau, Eduard I.; Sennov, Ruslan A.

    2007-09-15

    Experimental measurements and Monte Carlo simulation of the mean energy of backscattered electrons by Au/Si targets irradiated by electron beams have been made as a function of the Au layer thickness for primary electron energies in the range 8-20 keV. The simulated trends are compared to experimental data. The mean backscattered energy as a function of the layer thickness presents a maximum whose position depends on the primary energy. The simulated and experimental behaviors are in satisfactory agreement. Similarities and differences between experimental and Monte Carlo results are illustrated and briefly discussed. A somewhat unexpected effect is observed: the maximum of the mean backscattered energy of layered targets is higher than that of the elements constituting the system. This effect is discussed on the basis of semi-empirical considerations.

  17. Cold Climate Foundation Retrofit Experimental Hygrothermal Performance. Cloquet Residential Research Facility Laboratory Results

    SciTech Connect

    Goldberg, Louise F.; Harmon, Anna C.

    2015-04-09

    This project was funded jointly by the National Renewable Energy Laboratory (NREL) and Oak Ridge National Laboratory (ORNL). ORNL focused on developing a full basement wall system experimental database to enable others to validate hygrothermal simulation codes. NREL focused on testing the moisture durability of practical basement wall interior insulation retrofit solutions for cold climates. The project has produced a physically credible and reliable long-term hygrothermal performance database for retrofit foundation wall insulation systems in zone 6 and 7 climates that are fully compliant with the performance criteria in the 2009 Minnesota Energy Code. These data currently span the period from November 10, 2012 through May 31, 2014 and are anticipated to be extended through November 2014. The experimental data were configured into a standard format that can be published online and that is compatible with standard commercially available spreadsheet and database software.

  18. Performance of VAV Parallel Fan Powered Terminal Units: Experimental Results and Models 

    E-print Network

    Furr, J.; O'Neal, D.; Davis, M.; Bryant, J.; Cramlet, A.

    2008-01-01

    This paper is the first of three papers on the development of experimental performance models of variable air volume fan powered terminal units. Tests were conducted on both parallel and series fan powered terminal units. Data from these tests were used... to develop empirical models of airflow, power, and leakage of both parallel and series fan power terminal units. These models are suitable for use in annual energy use models of variable air volume systems in commer- cial buildings. This paper provides a...

  19. Modeling and experimental characterization of a fluttering windbelt for energy harvesting

    NASA Astrophysics Data System (ADS)

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

    2014-11-01

    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.

  20. The mapping of electronic energy distributions using experimental electron density.

    PubMed

    Tsirelson, Vladimir G

    2002-08-01

    It is demonstrated that the approximate kinetic energy density calculated using the second-order gradient expansion with parameters of the multipole model fitted to experimental structure factors reproduces the main features of this quantity in a molecular or crystal position space. The use of the local virial theorem provides an appropriate derivation of approximate potential energy density and electronic energy density from the experimental (model) electron density and its derivatives. Consideration of these functions is not restricted by the critical points in the electron density and provides a comprehensive characterization of bonding in molecules and crystals. PMID:12149553

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

    NASA Astrophysics Data System (ADS)

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

    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.

  2. Photon Detection with Cooled Avalanche Photodiodes: Theory and Preliminary Experimental Results

    NASA Technical Reports Server (NTRS)

    Robinson, D. L.; Hays, D. A.

    1985-01-01

    Avalanche photodiodes (APDs) can be operated in a geiger-tube mode so that they can respond to single electron events and thus be used as photon counting detectors. Operational characteristics and theory of APDs while used in this mode are analyzed and assessed. Preliminary experimental investigation of several commercially available APDs has commenced, and initial results for dark count statistics are presented.

  3. De-amortized Cuckoo Hashing: Provable Worst-Case Performance and Experimental Results

    E-print Network

    Naor, Moni

    De-amortized Cuckoo Hashing: Provable Worst-Case Performance and Experimental Results Yuriy Arbitman Moni Naor Gil Segev Abstract Cuckoo hashing is a highly practical dynamic dictionary: it provides '07) proposed a de-amortization of cuckoo hashing using queueing techniques that preserve its

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

    SciTech Connect

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

    2007-01-01

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

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

    E-print Network

    Kreiter, Andreas K.

    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

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

    ERIC Educational Resources Information Center

    Gates, Joshua

    2009-01-01

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

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

    E-print Network

    Tsiotras, Panagiotis

    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

  8. Multi-carrier Signal Transmission through HVAC Ducts: Experimental Results for Channel Capacity

    E-print Network

    Stancil, Daniel D.

    , for the first time, experimental results on channel capacity of heating, ventilation, and air-conditioning (HVAC.4 GHz Industrial, Scientific, and Medical (ISM) band. Experiments using actual synthesized signals--Multi-carrier transmission; indoor propagation; Heat- ing, Ventilation, and Air Conditioning (HVAC) Systems for wireless

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

    E-print Network

    Hoffmann, Heiko

    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

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

    E-print Network

    Lau, Kung-Kiu

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

  11. Experimental investigation of fatigue in a cantilever energy harvesting beam

    NASA Astrophysics Data System (ADS)

    Avvari, Panduranga Vittal; Yang, Yaowen; Liu, Peiwen; Soh, Chee Kiong

    2015-03-01

    Over the last decade, cantilever energy harvesters gained immense popularity owing to the simplicity of the design and piezoelectric energy harvesting (PEH) using the cantilever design has undergone considerable evolution. The major drawback of a vibrating cantilever beam is its vulnerability to fatigue over a period of time. This article brings forth an experimental investigation into the phenomenon of fatigue of a PEH cantilever beam. As there has been very little literature reported in this area, an effort has been made to scrutinize the damage due to fatigue in a linear vibrating cantilever PEH beam consisting of an aluminum substrate with a piezoelectric macro-fiber composite (MFC) patch attached near the root of the beam and a tip mass attached to the beam. The beam was subjected to transverse vibrations and the behavior of the open circuit voltage was recorded with passing time. Moreover, electro-mechanical admittance readings were obtained periodically using the same MFC patch as a Structural health monitoring (SHM) sensor to assess the health of the PEH beam. The results show that with passing time the PEH beam underwent fatigue in both the substrate and MFC, which is observed in a complimentary trend in the voltage and admittance readings. The claim is further supported using the variation of root mean square deviation (RMSD) of the real part of admittance (conductance) readings. Thus, this study concludes that the fatigue issue should be addressed in the design of PEH for long term vibration energy harvesting.

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

    E-print Network

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

    2015-09-18

    A master-worker architecture is presented for obtaining combined experimental results through joint fits of datasets from several experiments, ensuring that correlations are correctly taken into account and resulting in a better determination of nuisance parameters. The JFIT framework allows such joint fits to be performed keeping the data separated, in its original format, and using independent fitting environments. We present a C++ implementation of such a framework based on the ROOT package, and demonstrate its functionalities with concrete examples.

  13. The experimental results of AMTEC and a study of its terrestrial applications in IEE of China

    SciTech Connect

    Ni, Q.; Tong, J.; Kan, Y.; Wang, J.; Cui, Y.

    1997-12-31

    The R and D activities in the field of AMTEC research at The Institute of Electrical Engineering, Chinese Academy of Sciences are introduced. The outline of experimental facility with a single tube cell is described. The experimental results so far are reported followed by an analysis of electrical characteristic, in particular, an evaluation of characteristic of BASE/porous electrode interface with the effective sheet resistivity and the electrode efficiency. The approaches for improving device performance are discussed. The terrestrial applications of AMTEC in China are considered as an alternative of conventional diesel-generators. The possibility of AMTEC power supply for some separate sites is predicted.

  14. An Experimental Investigation of Occupancy-Based Energy-Efficient Control of Commercial Building Indoor Climate

    E-print Network

    Carloni, Luca

    An Experimental Investigation of Occupancy-Based Energy-Efficient Control of Commercial Building evaluation of a scalable control algorithm for a commercial building heating, ventilation, and air-conditioning (HVAC) sys- tem. The experiments showed that the controller resulted in 37% energy savings without

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

    NASA Technical Reports Server (NTRS)

    Goldhirsh, Julius; Vogel, Wolfhard J.

    1992-01-01

    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.

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

    SciTech Connect

    Cherne, Frank J; Jensen, Brian J; Rigg, Paulo A; Elkin, Vyacheslav M

    2009-01-01

    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.

  17. Evaluating Impacts of CO2 Gas Intrusion Into a Confined Sandstone aquifer: Experimental Results

    SciTech Connect

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

    2014-12-31

    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.

  18. Evaluating Impacts of CO2 Gas Intrusion Into a Confined Sandstone aquifer: Experimental Results

    DOE PAGESBeta

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

    2014-12-31

    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 Partnershipmore »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.« less

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

    SciTech Connect

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

    2003-11-01

    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.

  20. Thermally stimulated luminescence and conductivity - theoretical models and their applicability to experimental results

    NASA Astrophysics Data System (ADS)

    Sunta, C. M.; Kulkarni, R. N.; Ayta, W. E. F.; Chubaci, J. F. D.; Watanabe, S.

    In this paper computational glow curves are presented for commonly used models by varying the various parameters in the respective models. The characteristics of the computed glow curves are discussed in the following aspects: (i) temperature of maximum intensity, (ii) shape of the glow curve, (iii) kinetics order b, in particular the relevance of non-integral order and the condition causing it, (iv) pre-exponential factor s' and its dimensions, (v) possible relationship of empirical parameters (b and s') with the physical parameters, (vi) growth of intensity as a function of trap occupancy, (vii) pre-dose sensitization, (viii) applicability of different models to experimental results from some commonly studied materials, (ix) role of trapping/untrapping transitions and other physico-chemical processes during thermal stimulation of emission and (x) relevance of computerized fitting and deconvolution of experimentally obtained glow curves. The results of the study show that in general the glow peaks shift their position and undergo change in their shape when the trap occupancy (dose) is changed. The exceptions to this general behaviour occur only when the applicable value of kinetic order b is 1 at all trap occupancies. These theoretical glow curve behaviours are discussed in the perspective of those observed experimentally in most materials. It is concluded that among the various models in vogue, it is only the interactive trap system model which is commensurate with the experimental observations.

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

    NASA Astrophysics Data System (ADS)

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

    2014-05-01

    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).

  2. Experimental and theoretical research in high energy astrophysics

    NASA Technical Reports Server (NTRS)

    Clark, George W.

    1990-01-01

    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.

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

    SciTech Connect

    SAMIOS,N.P.

    2002-01-18

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

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

    NASA Technical Reports Server (NTRS)

    Smith-Taylor, Rudeen; Tanner, Sharon E.

    1993-01-01

    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.

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

    NASA Astrophysics Data System (ADS)

    Dirba, I.; Kleperis, J.

    2011-01-01

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

  6. Experimental Studies of Elementary Particle Interactions at High Energies

    SciTech Connect

    Goulianos, Konstantin

    2013-07-31

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

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

    SciTech Connect

    Stein, D.J.; Spera, F.J. )

    1993-09-15

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

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

    NASA Astrophysics Data System (ADS)

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

    1992-08-01

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

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

    SciTech Connect

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

    2008-06-23

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2013-09-01

    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.

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

    E-print Network

    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

    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.

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

    SciTech Connect

    Sinitsyn, Oleksandr; Nusinovich, Gregory; Antonsen, Thomas Jr.

    2010-11-04

    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.

  13. Summary of experimental heat-transfer results from the turbine hot section facility

    NASA Technical Reports Server (NTRS)

    Gladden, Herbert J.; Yeh, Fredrick C.

    1993-01-01

    Experimental data from the turbine Hot Section Facility are presented and discussed. These data include full-coverage film-cooled airfoil results as well as special instrumentation results obtained at simulated real engine conditions. Local measurements of airfoil wall temperature, airfoil gas-path static-pressure distribution, and local heat-transfer coefficient distributions are presented and discussed. In addition, measured gas and coolant temperatures and pressures are presented. These data are also compared with analyses from Euler and boundary-layer codes.

  14. The 3D structure of the hadrons: recents results and experimental program at Jefferson Lab

    SciTech Connect

    Munoz Camacho, Carlos

    2014-04-01

    The understanding of Quantum Chromodynamics (QCD) at large distances still remains one of the main outstanding problems of nuclear physics. Studying the internal structure of hadrons provides a way to probe QCD in the non-perturbative domain and can help us unravel the internal structure of the most elementary blocks of matter. Jefferson Lab (JLab) has already delivered results on how elementary quarks and gluons create nucleon structure and properties. The upgrade of JLab to 12 GeV will allow the full exploration of the valence-quark structure of nucleons and the extraction of real threedimensional pictures. I will present recent results and review the future experimental program at JLab.

  15. Cold Climate Foundation Retrofit Experimental Hygrothermal Performance: Cloquet Residential Research Facility Laboratory Results

    SciTech Connect

    Goldberg, Louise F.; Harmon, Anna C.

    2015-04-01

    Thermal and moisture problems in existing basements create a unique challenge because the exterior face of the wall is not easily or inexpensively accessible. This approach addresses thermal and moisture management from the interior face of the wall without disturbing the exterior soil and landscaping. the interior and exterior environments. This approach has the potential for improving durability, comfort, and indoor air quality. This project was funded jointly by the National Renewable Energy Laboratory (NREL) and Oak Ridge National Laboratory (ORNL). ORNL focused on developing a full basement wall system experimental database to enable others to validate hygrothermal simulation codes. NREL focused on testing the moisture durability of practical basement wall interior insulation retrofit solutions for cold climates. The project has produced a physically credible and reliable long-term hygrothermal performance database for retrofit foundation wall insulation systems in zone 6 and 7 climates that are fully compliant with the performance criteria in the 2009 Minnesota Energy Code. The experimental data were configured into a standard format that can be published online and that is compatible with standard commercially available spreadsheet and database software.

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

    NASA Technical Reports Server (NTRS)

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

    2005-01-01

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2010-08-01

    The present work compares simulations made using the OpenFOAM CFD code with experimental measurements of the flow in the U9 Kaplan turbine model. Comparisons of the velocity profiles in the spiral casing and in the draft tube are presented. The U9 Kaplan turbine prototype located in Porjus and its model, located in Älvkarleby, Sweden, have curved inlet pipes that lead the flow to the spiral casing. Nowadays, this curved pipe and its effect on the flow in the turbine is not taken into account when numerical simulations are performed at design stage. To study the impact of the inlet pipe curvature on the flow in the turbine, and to get a better overview of the flow of the whole system, measurements were made on the 1:3.1 model of the U9 turbine. Previously published measurements were taken at the inlet of the spiral casing and just before the guide vanes, using the laser Doppler anemometry (LDA) technique. In the draft tube, a number of velocity profiles were measured using the LDA techniques. The present work extends the experimental investigation with a horizontal section at the inlet of the draft tube. The experimental results are used to specify the inlet boundary condition for the numerical simulations in the draft tube, and to validate the computational results in both the spiral casing and the draft tube. The numerical simulations were realized using the standard k-e model and a block-structured hexahedral wall function mesh.

  18. Wind Code Application to External Forebody Flowfields with Comparisons to Experimental Results

    NASA Technical Reports Server (NTRS)

    Frate, F. C.; Kim, H. D.

    2001-01-01

    The WIND Code, a general purpose Navier-Stokes solver, has been utilized to obtain supersonic external flowfield Computational Fluid Dynamics (CFD) solutions over an axisymmetric, parabolic forebody with comparisons made to wind tunnel experimental results. Various cases have been investigated at supersonic freestream conditions ranging from Mach 2.0 to 3.5, at 0 deg and 3 deg angles-of-attack, and with either a sharp-nose or blunt-nose forebody configuration. Both a turbulent (Baldwin-Lomax algebraic turbulence model) and a laminar model have been implemented in the CFD. Obtaining the solutions involved utilizing either the parabolized- or full-Navier-Stokes analyses supplied in WIND. Comparisons have been made with static pressure measurements, with boundary-layer rake and flowfield rake pitot pressure measurements, and with temperature sensitive paint experimental results. Using WIND's parabolized Navier-Stokes capability, grid sequencing, and the Baldwin-Lomax algebraic turbulence model allowed for significant reductions in computational time while still providing good agreement with experiment. Given that CFD and experiment compare well, WIND is found to be a good computational platform for solving this type of forebody problem, and the grids developed in conjunction with it will be used in the future to investigate varying freestream conditions not tested experimentally.

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

    SciTech Connect

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

    2001-08-01

    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.

  20. Respiratory rate detection algorithm based on RGB-D camera: theoretical background and experimental results

    PubMed Central

    Freddi, Alessandro; Monteriù, Andrea; Longhi, Sauro

    2014-01-01

    Both the theoretical background and the experimental results of an algorithm developed to perform human respiratory rate measurements without any physical contact are presented. Based on depth image sensing techniques, the respiratory rate is derived by measuring morphological changes of the chest wall. The algorithm identifies the human chest, computes its distance from the camera and compares this value with the instantaneous distance, discerning if it is due to the respiratory act or due to a limited movement of the person being monitored. To experimentally validate the proposed algorithm, the respiratory rate measurements coming from a spirometer were taken as a benchmark and compared with those estimated by the algorithm. Five tests were performed, with five different persons sat in front of the camera. The first test aimed to choose the suitable sampling frequency. The second test was conducted to compare the performances of the proposed system with respect to the gold standard in ideal conditions of light, orientation and clothing. The third, fourth and fifth tests evaluated the algorithm performances under different operating conditions. The experimental results showed that the system can correctly measure the respiratory rate, and it is a viable alternative to monitor the respiratory activity of a person without using invasive sensors.

  1. Experimental laser anastomosis of the large bowel: conclusive results and future prospect

    NASA Astrophysics Data System (ADS)

    Kawahara, Masaki; Kuramoto, Shu; Ryan, Peter

    2003-06-01

    Completely sutureless end-to-end large bowel anastomoses were successfully performed in New Zealand white rabbits by using 1064 nm, 0.4-W power pulsating Nd:YAG laser to produce welding. Purpose: The aim of this study was to assess the results of our whole experimental data and summarize our experimental work on laser colon anastomosis. Methods: This experimental study investigated integrity of anastomosis, degree of narrowing, macroscopic appearance, microscopic findings, animal body weight change, and collagen concentration of laser colon anastomoses, compared with those of conventional sutured anastomoses up to ninety postoperative days. Results: Bursting pressures of laser anastomoses were at first low and came to be equivalent at seven days, but the laser group exhibited a consistent narrowing tendency. However, laser anastomoses demonstrated fewer and milder adhesions, and animals showed a better recovery of body weight. Histologically, laser anastomoses showed better layer-to-layer reconstitution without foreign body response and with less fibrosis. Difference in collagen concentration did not reach statistical significance. Conclusion: The technique of laser anastomosis presents a promising alternative to suturing in reconstitution of the large bowel.

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

    NASA Technical Reports Server (NTRS)

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

    2006-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2008-06-01

    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.

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

    NASA Technical Reports Server (NTRS)

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

    2012-01-01

    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

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

    SciTech Connect

    Somers, D. M.

    2005-01-01

    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.

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

    NASA Technical Reports Server (NTRS)

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

    2006-01-01

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

  7. 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...

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

    E-print Network

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

    1994-01-01

    meters are often used to integrate and display flow and energy data or generate a totalized signal for input into a data acquisition system. In this paper new results from calibration efforts in the LoanSTAR program are presented, including the premature... or generate a totalized signal that can be recorded by data acquisition system. The accuracy of totalized flow and energy measurements is directly effected by the quality of thermal and flow measurement devices. In a closed-loop system a thermal energy meter...

  9. Focusing effect of bent GaAs crystals for gamma-ray Laue lenses: Monte Carlo and experimental results

    E-print Network

    Virgilli, E; Rosati, P; Bonnini, E; Buffagni, E; Ferrari, C; Stephen, J B; Caroli, E; Auricchio, N; Basili, A; Silvestri, S

    2015-01-01

    We report on results of observation of the focusing effect from the planes (220) of Gallium Arsenide (GaAs) crystals. We have compared the experimental results with the simulations of the focusing capability of GaAs tiles through a developed Monte Carlo. The GaAs tiles were bent using a lapping process developed at the cnr/imem - Parma (Italy) in the framework of the laue project, funded by ASI, dedicated to build a broad band Laue lens prototype for astrophysical applications in the hard X-/soft gamma-ray energy range (80-600 keV). We present and discuss the results obtained from their characterization, mainly in terms of focusing capability. Bent crystals will significantly increase the signal to noise ratio of a telescope based on a Laue lens, consequently leading to an unprecedented enhancement of sensitivity with respect to the present non focusing instrumentation.

  10. Energy Monitoring--Objectives vs Results 

    E-print Network

    McEver, R. M. Jr.

    1986-01-01

    Universities, hospitals and similar institutions, as well as manufacturers and plants have implemented programs of utility submetering. Submetering of utilities is defined as the measurement of energy at or near the ...

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

    SciTech Connect

    BURRELL,HK

    2002-11-01

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

  12. Energy: government policy or market result

    SciTech Connect

    Reagan, M.D.

    1983-03-01

    From the Truman presidency through that of Carter, the United States worked fitfully toward the development of an energy policy. Now, consistent with the free market philosophy of the Reagan Administration, the 1981 National Energy Policy Plan proposes that individual choices and reliance on market decisions replace regulations and subsidies in the nation's strategy for energy. This paper starts from the assumption that the Spring, 1982 oil glut may turn out to be a rather temporary thing. If one therefore wants to pursue a policy strategy that will protect us in the case of sudden short-term supply disruptions and also work toward long-term energy-supply diversification, how far will market reliance carry us. What is a range of policies and programs that might usefully supplement the market. What are the externalities for which compensatory actions may still be needed if one would like to employ the market strategy as a basic thrust. The scope of the paper includes contingency planning, synthetic-fuel development, renewables (especially solar energy), conservation, equity issues, environmental externalities, and the conceptualization of policies differentiated as energy, environmental, or economic.

  13. Theoretical modelling and experimental results of electromechanical actuation of an elastomer

    NASA Astrophysics Data System (ADS)

    Díaz-Calleja, Ricardo; Llovera-Segovia, Pedro; Dominguez, José Jorge; Carsí Rosique, Marta; Quijano Lopez, Alfredo

    2013-06-01

    Electromechanical actuation is a growing field of research today both for applications or theoretical modelling. The interaction between electric and mechanical constraints has been used for electromechanic actuators or generators based on elastomers. From a theoretical point of view, many recent works have been focused on uniaxial or biaxial stretching of elastomer plates with compliant electrodes. Free stretching or pre-strained samples have been theoretically modelled, mainly by neo-Hookean equations. In this work, we present theoretical and experimental results of electromechanic actuation of an elastomer (the widely used 3M VHB4910, an acrylic foam) in a pre-strained case and a free case. Experimental characterization of the material shows that the Ogden model gives the best accurate fitting of mechanical properties. Thus, a theoretical development based on this model is carried out in order to obtain the curves describing the electromechanical behaviour of the material. The mechanical instability related to wrinkling of the material is theoretically calculated and experimentally verified.

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

    NASA Technical Reports Server (NTRS)

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

    2011-01-01

    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.

  15. Experimental results of 40-kA Nb3Al conductor

    NASA Astrophysics Data System (ADS)

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

    1993-03-01

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

  16. Transdermal flux predictions for selected selective oestrogen receptor modulators (SERMs): comparison with experimental results.

    PubMed

    Güngör, Sevgi; Delgado-Charro, M Begoña; Masini-Etévé, Valérie; Potts, Russell O; Guy, Richard H

    2013-12-28

    The aim of this work was to evaluate the feasibility of delivering transdermally a series of highly lipophilic compounds (log P ~4-7), comprising several selective oestrogen receptor modulators and a modified testosterone (danazol). The maximum fluxes of the drugs were predicted theoretically using the modified Potts & Guy algorithm (to determine the permeability coefficient (kp) from water) and the calculated aqueous solubilities. The correction provided by Cleek & Bunge took into account the contribution of the viable epidermal barrier to the skin permeation of highly lipophilic compounds. Experimental measurements of drug fluxes from saturated hydroalcoholic solutions were determined in vitro through excised pig skin. Overall, the predicted fluxes were in good general agreement (within a factor of 10) with the experimental results. Most of the experimental fluxes were greater than those predicted theoretically suggesting that the 70:30 v/v ethanol-water vehicle employed may have had a modest skin penetration enhancement effect. This investigation shows that the transdermal fluxes of highly lipophilic compounds can be reasonably predicted from first principles provided that the viable epidermis, underlying the stratum corneum, is included as a potentially important contributor to the skin's overall barrier function. Furthermore, the absolute values of the measured fluxes, when considered in parallel with previous clinical studies, indicate that it might be feasible to topically deliver a therapeutically useful amount of some of the compounds considered to treat cancerous breast tissue. PMID:24076520

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

    NASA Astrophysics Data System (ADS)

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

    1995-04-01

    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.

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

    NASA Technical Reports Server (NTRS)

    Scharrer, Joseph Kirk

    1987-01-01

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2010-06-01

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2010-05-01

    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.

  1. Failure properties of two porous sandstones: experimental results and the applicability of a theoretical prediction

    NASA Astrophysics Data System (ADS)

    Ma, X.; Rudnicki, J. W.; Haimson, B. C.

    2013-12-01

    True triaxial experiments have been performed in Coconino (n = 17%) and Bentheim (n = 24%) sandstones using two distinct loading paths. Tests using a novel loading path maintain a constant deviatoric stress state N (= -?2(?2 - ?oct)/?oct, Rudnicki and Rice, 1975), by keeping ?3 constant and raising ?1 and ?2 simultaneously at a predetermined ratio of (?2 - ?3)/(?1 - ?3) until failure occurs. Experiments were conducted for an array of seven ?3 magnitudes between 0 and 150 MPa, and five stress ratios (between 0 and 1), i.e., five N magnitudes between +1 (axisymmetric compression) and -1 (axisymmetric extension). Test data for Coconino show that for each constant N the octahedral shear stress at failure, ?oct,f, rises as the mean stress, ?oct,f increases, albeit at a decreasing rate; in Bentheim sandstone, ?oct,f not only rises at a decreasing rate with increasing ?oct,f, but reaches a peak and forms a ';cap', beyond which it continuously drops with a rise in ?oct,f. In both rocks, for a constant ?oct,f, ?oct,f typically increases as N varies from +1 (?2 = ?3) to -1 (?2 = ?1). Tests using the common loading path, maintain constant both ?2 and ?3, while raising ?1 monotonically to failure (?1,peak). In these tests, ?1,peak first rises with an increase in the constant ?2 beyond ?2 = ?3. The rate of increase slows down for higher ?2, until a top magnitude is reached, beyond which ?1,peak drops continuously as ?2 is raised from test to test, and approaches its initial magnitude when ?2 = ?1. Under the assumption that ?2 effect on failure in the common loading path tests is caused by changes in both ?oct and N, we fitted the novel test data with the three-invariant failure representation F (?oct, ?oct, N) = 0 (proposed by Rudnicki, 2008), and used this expression to predict ?1,peak = f (?2, ?3) for each constant ?3 series. We then compared the experimental results with the theoretical predictions. The failure prediction in both sandstones generally replicates the strengthening effect of ?2 observed experimentally. In Coconino, predicted ?1,peak underestimates somewhat experimental magnitudes at the two extremes of ?2 (?2 = ?3 and ?2 = ?1). In Bentheim, the trend for the theoretical failure point is to slightly over-predict experimental results. Generally, the predicted ?1,peak in both sandstones yields a reasonable fit to experimental data.

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

    PubMed

    Fricke, Moritz B; Rolfes, Raimund

    2013-11-01

    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

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

    NASA Technical Reports Server (NTRS)

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

    1991-01-01

    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.

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

    NASA Technical Reports Server (NTRS)

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

    1992-01-01

    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.

  5. Preliminary Results on the Experimental Investigation of the Structure Functions of Bound Nucleons

    SciTech Connect

    Bodek, Arie

    2015-09-01

    We present preliminary results on an experimental study of the nuclear modification of the longitudinal (sL) and transverse (sT ) structure functions of nucleons bound in nuclear targets. The origin of these modifications (commonly referred as as the EMC effect) is not fully understood. Our measurements of R= sL=sT for nuclei (RA) and for deuterium (RD) indicate that nuclear modifications of the structure functions of bound nucleons are different for the longitudinal and transverse structure functions, and that contrary to expectation from several theoretical models, RA < RD.

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

    NASA Technical Reports Server (NTRS)

    Dewey, J. S.; Devasia, Santosh

    1996-01-01

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

  7. Experimental and Theoretical Results in Output Trajectory Redesign for Flexible Structures

    NASA Technical Reports Server (NTRS)

    Dewey, J. S.; Leang, K.; Devasia, S.

    1998-01-01

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

  8. The density-of-states concept versus the experimentally determined distribution of activation energies

    SciTech Connect

    Adriaenssens, G.J.; Arkhipov, V.I.

    1996-12-31

    Random fluctuations of localized state energies will result in thermal release of carriers trapped in those states at shorter times than would be observed from a stationary distribution of the same energies. An experimentally observed distribution of activation energies will hence differ from the distribution of average energies of the states involved. It will also be temperature-dependent. In a-Si:H, low-frequency fluctuations with a spectrum comparable to the one of 1/f noise, can account for the measured temperature dependence of the distribution. They also explain the apparent shift in localized-state energy under steady-state illumination.

  9. 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

    Little, Priscilla M. D.; Harris, Erin

    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…

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

    NASA Technical Reports Server (NTRS)

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

    1982-01-01

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

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

    SciTech Connect

    Zhang, Jinsuo

    2008-01-01

    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.

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

    NASA Technical Reports Server (NTRS)

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

    1984-01-01

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

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

    NASA Technical Reports Server (NTRS)

    Curtis, S. B.

    1994-01-01

    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.

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

    NASA Technical Reports Server (NTRS)

    Childs, Dara W.; Alexander, Chis

    1994-01-01

    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.

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

    SciTech Connect

    Schmitz-Rode, Thomas; Vorwerk, Dierk; Schuermann, Karl; Guenther, Rolf W.

    1996-04-15

    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.

  16. Tilted wheel satellite attitude control with air-bearing table experimental results

    NASA Astrophysics Data System (ADS)

    Inumoh, Lawrence O.; Forshaw, Jason L.; Horri, Nadjim M.

    2015-12-01

    Gyroscopic actuators for satellite control have attracted significant research interest over the years, but their viability for the control of small satellites has only recently started to become clear. Research on variable speed gyroscopic actuators has long been focused on single gimbal actuators; double gimbal actuators typically operate at constant wheel spin rate and allow tilt angle ranges far larger than the ranges needed to operate most satellite missions. This research examines a tilted wheel, a newly proposed type of inertial actuator that can generate torques in all three principal axes of a rigid satellite using a spinning wheel and a double tilt mechanism. The tilt mechanism tilts the angular momentum vector about two axes providing two degree of freedom control, while variation of the wheel speed provides the third. The equations of motion of the system lead to a singularity-free system during nominal operation avoiding the need for complex steering logic. This paper describes the hardware design of the tilted wheel and the experimental setup behind both standalone and spherical air-bearing tables used to test it. Experimental results from the air bearing table are provided with the results depicting the high performance capabilities of the proposed actuator in torque generation.

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

    SciTech Connect

    Maryuama, Koichi; Narita, Yoshihiro; Ichinomiya, Osamu

    1995-11-01

    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.

  18. Transport of fluorobenzoate tracers in a vegetated hydrologic control volume: 1. Experimental results

    NASA Astrophysics Data System (ADS)

    Queloz, Pierre; Bertuzzo, Enrico; Carraro, Luca; Botter, Gianluca; Miglietta, Franco; Rao, P. S. C.; Rinaldo, Andrea

    2015-04-01

    This paper reports about the experimental evidence collected on the transport of five fluorobenzoate tracers injected under controlled conditions in a vegetated hydrologic volume, a large lysimeter (fitted with load cells, sampling ports, and an underground chamber) where two willows prompting large evapotranspiration fluxes had been grown. The relevance of the study lies in the direct and indirect measures of the ways in which hydrologic fluxes, in this case, evapotranspiration from the upper surface and discharge from the bottom drainage, sample water and solutes in storage at different times under variable hydrologic forcings. Methods involve the accurate control of hydrologic inputs and outputs and a large number of suitable chemical analyses of water samples in discharge waters. Mass extraction from biomass has also been performed ex post. The results of the 2 year long experiment established that our initial premises on the tracers' behavior, known to be sorption-free under saturated conditions which we verified in column leaching tests, were unsuitable as large differences in mass recovery appeared. Issues on reactivity thus arose and were addressed in the paper, in this case attributed to microbial degradation and solute plant uptake. Our results suggest previously unknown features of fluorobenzoate compounds as hydrologic tracers, potentially interesting for catchment studies owing to their suitability for distinguishable multiple injections, and an outlook on direct experimental closures of mass balance in hydrologic transport volumes involving fluxes that are likely to sample differently stored water and solutes.

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

    NASA Astrophysics Data System (ADS)

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

    2014-06-01

    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.

  20. Survey of Experimental Results in High-Contrast Imaging for Future Exoplanet Missions

    NASA Technical Reports Server (NTRS)

    Lawson, P. R.; Belikov, R.; Cash, W.; Clampin, M.; Glassman, T.; Guyon, O.; Kasdin, N. J.; Kern, B. D.; Lyon, R.; Mawet, D.; Moody, D.; Samuele, R.; Serabyn, E.; Sirbu, D.; Trauger, J.

    2013-01-01

    We present and compare experimental results in high contrast imaging representing the state of the art in coronagraph and starshade technology. These experiments have been undertaken with the goal of demonstrating the capability of detecting Earth-like planets around nearby Sun-like stars. The contrast of an Earth seen in reflected light around a Sun-like star would be about 1.2 x 10(exp -10). Several of the current candidate technologies now yield raw contrasts of 1.0 x 10(exp -9) or better, and so should enable the detection of Earths, assuming a gain in sensitivity in post-processing of a factor of 10. We present results of coronagraph and starshade experiments conducted at visible and infrared wavelengths. Cross-sections of dark fields are directly compared as a function of field angle and bandwidth. The strength and differences of the techniques are compared.

  1. Fault detection, isolation and reconfiguration in FTMP Methods and experimental results. [fault tolerant multiprocessor

    NASA Technical Reports Server (NTRS)

    Lala, J. H.

    1983-01-01

    The Fault-Tolerant Multiprocessor (FTMP) is a highly reliable computer designed to meet a goal of 10 to the -10th failures per hour and built with the objective of flying an active-control transport aircraft. Fault detection, identification, and recovery software is described, and experimental results obtained by injecting faults in the pin level in the FTMP are presented. Over 21,000 faults were injected in the CPU, memory, bus interface circuits, and error detection, masking, and error reporting circuits of one LRU of the multiprocessor. Detection, isolation, and reconfiguration times were recorded for each fault, and the results were found to agree well with earlier assumptions made in reliability modeling.

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

    NASA Technical Reports Server (NTRS)

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

    1976-01-01

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

  3. Fundamental finite element evaluation of a three dimensional rolled thread form: Modelling and experimental results

    SciTech Connect

    Martin, J.A.

    1998-07-01

    This paper presents an evaluation of residual stresses generated by a cold rolled thread forming process. Major factors associated with the forming process which affect the residual stress state and are addressed include: stress-strain relations, effects of friction and contact on plastic deformation, and the influence of manufacturing parameters. MARC finite element software is used to determine the stresses and deformation that occur in a multipass cold rolled flat plate with a modified ACME thread form. Variations in friction, contact, and manufacturing parameters are assessed based on relative comparison of results. Stress results for selected parameters are compared to experimentally measured data generated using X-ray diffraction and hole drilling techniques.

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

    NASA Technical Reports Server (NTRS)

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

    1991-01-01

    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.

  5. Experimental Results for a Flapped Natural-laminar-flow Airfoil with High Lift/drag Ratio

    NASA Technical Reports Server (NTRS)

    Mcghee, R. J.; Viken, J. K.; Pfenninger, W.; Beasley, W. D.; Harvey, W. D.

    1984-01-01

    Experimental results have been obtained for a flapped natural-laminar-flow airfoil, NLF(1)-0414F, in the Langley Low-Turbulence Pressure Tunnel. The tests were conducted over a Mach number range from 0.05 to 0.40 and a chord Reynolds number range from about 3.0 x 10(6) to 22.0 x 10(6). The airfoil was designed for 0.70 chord laminar flow on both surfaces at a lift coefficient of 0.40, a Reynolds number of 10.0 x 10(6), and a Mach number of 0.40. A 0.125 chord simple flap was incorporated in the design to increase the low-drag, lift-coefficient range. Results were also obtained for a 0.20 chord split-flap deflected 60 deg.

  6. Experimental results of a new system using microwaves for vision correction

    NASA Astrophysics Data System (ADS)

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

    2009-02-01

    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.

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

    NASA Technical Reports Server (NTRS)

    Banin, A.; Rishpon, J.

    1979-01-01

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

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

    SciTech Connect

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

    2013-11-15

    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.

  9. Immiscible liquid-liquid pressure-driven flow in capillary tubes: Experimental results and numerical comparison

    NASA Astrophysics Data System (ADS)

    Soares, Edson J.; Thompson, Roney L.; Niero, Debora C.

    2015-08-01

    The immiscible displacement of one viscous liquid by another in a capillary tube is experimentally and numerically analyzed in the low inertia regime with negligible buoyancy effects. The dimensionless numbers that govern the problem are the capillary number Ca and the viscosity ratio of the displaced to the displacing fluids N?. In general, there are two output quantities of interest. One is associated to the relation between the front velocity, Ub, and the mean velocity of the displaced fluid, U ¯ 2 . The other is the layer thickness of the displaced fluid that remains attached to the wall. We compute these quantities as mass fractions in order to make them able to be compared. In this connection, the efficiency mass fraction, me, is defined as the complement of the mass fraction of the displaced fluid that leaves the tube while the displacing fluid crosses its length. The geometric mass fraction, mg, is defined as the fraction of the volume of the layer that remains attached to the wall. Because in gas-liquid displacement, these two quantities coincide, it is not uncommon in the literature to use mg as a measure of the displacement efficiency for liquid-liquid displacements. However, as is shown in the present paper, these two quantities have opposite tendencies when we increase the viscosity of the displacing fluid, making this distinction a crucial aspect of the problem. Results from a Galerkin finite element approach are also presented in order to make a comparison. Experimental and numerical results show that while the displacement efficiency decreases, the geometrical fraction increases when the viscosity ratio decreases. This fact leads to different decisions depending on the quantity to be optimized. The quantitative agreement between the numerical and experimental results was not completely achieved, especially for intermediate values of Ca. The reasons for that are still under investigation. The experiments conducted were able to achieve a wide range of Ca. We show that in the range 1 < N? < 2, wavy shape instabilities appear at the interface and that increasing capillary number the amplitude of those waves increases. A deeper investigation on the operation window where these instabilities occur is in order.

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

    SciTech Connect

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

    2002-06-01

    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.

  11. Frequency-dependent seismic attenuation in shales: experimental results and theoretical analysis

    NASA Astrophysics Data System (ADS)

    Delle Piane, Claudio; Sarout, Joel; Madonna, Claudio; Saenger, Erik H.; Dewhurst, David N.; Raven, Mark

    2014-07-01

    Samples of shales from the Ordovician Bongabinni and Goldwyer source rock formations were recovered from the Canning Basin (Western Australia). Attenuation was experimentally measured on preserved plugs from these formations in the frequency range between 10-2 and 102 Hz. Samples cored with different orientations with respect to the sedimentary bedding were prepared and tested in their native saturated state and after drying in the oven at 105 °C for 24 hr to assess the effect of fluids and of the sediment anisotropy on attenuation. To aid the interpretation of the experimental results, the clay-rich samples were characterized in terms of mineralogy, water content, porosity, permeability and microstructure. The two shales have significantly different quality factors; and this is seen to be dependent on both the saturation state of the samples and the propagation direction of the oscillatory signal. The attenuation coefficient for compression/extension parallel to bedding is less than that vertical to bedding in both the preserved and partially dehydrated situations. No frequency dependency is observed in the preserved samples within the range of frequencies explored in this study. On the other hand partially saturated samples show peaks in attenuation at around 40 Hz when the stress perturbation is transmitted normal to the macroscopic bedding. The interpretation of the attenuation measurements in terms of well-established theoretical models is discussed in view of the physical characteristics and microstructure of the tested rocks.

  12. Numerical and experimental study of local heat transfer enhancement in helically coiled pipes. Preliminary results.

    NASA Astrophysics Data System (ADS)

    Bozzoli, F.; Cattani, L.; Rainieri, S.; Zachár, A.

    2015-11-01

    In the last years, the attention of heat transfer equipments manufacturers turned toward helically coiled-tube heat exchangers, especially with regards to applications for viscous and/or particulate products. The recent progress achieved in numerical simulation motivated many research groups to develop numerical models for this kind of apparatuses. These models, intended both to improve the knowledge of the fundamental heat transfer mechanisms in curved geometries and to support the industrial design of this kind of apparatuses, are usually validated throughout the comparison with either theoretical or experimental evidences by considering average heat transfer performances. However, this approach doesn't guarantee that the validated models are able to reproduce local effects in details, which are so important in this kind of non-standard geometries. In the present paper a numerical model of convective heat transfer in coiled tubes for laminar flow regime was formulated and discussed. Its goodness was checked throughout the comparison with the latest experimental outcomes of Bozzoli et al. [1] in terms of convective heat flux distribution along the boundary of the duct, by ensuring the effectiveness of the model also in the description of local behaviours. Although the present paper reports only preliminary results of this simulation/validation process, it could be of interest for the research community because it proposes a novel approach that could be useful to validate many numerical models for nonstandard geometries.

  13. Experimental results and modeling tests of an adsorptive air-conditioning unit

    SciTech Connect

    Guilleminot, J.J.; Poyelle, F.; Meunier, F.

    1998-10-01

    Experimental tests have been performed on a zeolite-water adsorptive system suitable for air conditioning and consisting of two adsorbers filled with a consolidated composite made of zeolite mixed with a highly conductive matrix. This paper describes the experimental results of such a heat pump unit operating with a heat and mass recovery cycle. An important enhancement of the specific cooling power (SCP) has been achieved. At evaporating temperature T = 4 C, mass transfer resistance controls the process and limits the expected COP. Tests carried out at higher evaporating pressure make it possible to achieve the predicted COP and SCP. A predictive model developed and validated elsewhere in order to describe the temperature evolution of components and the heat and mass transfer in the adsorbers explains the mass transfer resistance in the adsorbent. Last, a new highly conductive adsorbent composite with good mass transfer properties is developed. The model is used to predict the performances of this new material. Very good SCP and COP can be achieved.

  14. Experimental investigations of trace element fractionation in iron meteorites. I - Early results

    NASA Technical Reports Server (NTRS)

    Bild, R. W.; Drake, M. J.

    1978-01-01

    Experimental procedures for measuring trace element partitioning among metal and sulfide and silicate phases are described, and solid metal/liquid metal partition coefficients for minor and trace elements in the Fe-Ni system at 5 to 14% Ni are reported. The bulk compositions desired are homogenized at superliquidus temperature for 15-24 hours, held at a temperature in the solid/liquid two phase region for about 24 hours, and quenched to freeze in the equilibrium compositions. Run products are analyzed by electron microprobe. With the exception of Cr, all preliminary partition coefficients obtained are in the same sense as values derived from iron meteorites. The partition coefficients for Cr in solid metal/liquid metal and metal/troilite systems suggest that IIIAB and main group pallasites equilibrated with 9-22% troilite. A second method which makes it possible to place upper and lower limits on the partition coefficient by holding part of the sample at subliquidus and part at superliquidus temperatures, yielded significantly different results for the two metals tested (Au and Pt) from those obtained by the first method, demonstrating the importance of a close approach to equilibrium before using experimentally-determined partition coefficients to test empirical differentiation models for iron meteorites.

  15. First experimental results of time-of-flight reconstruction on an LSO PET scanner

    NASA Astrophysics Data System (ADS)

    Conti, Maurizio; Bendriem, Bernard; Casey, Mike; Chen, Mu; Kehren, Frank; Michel, Christian; Panin, Vladimir

    2005-10-01

    Time-of-flight (TOF) positron emission tomography (PET) was studied and preliminarily developed in the 1980s, but the lack of a scintillator able to deliver at the same time proper time resolution and stopping power has prevented this technique from becoming widespread and commercially available. With the introduction of LSO in PET, TOF is now a feasible option. TOF reconstruction has been implemented in the CPS Hi-Rez PET scanner, both with 2D filtered-back-projection (FBP2D) and 3D ordered subset expectation maximization (OSEM3D). A new procedure has been introduced in the time alignment to compensate for the limited digital time resolution of the present electronics. A preliminary version of scatter correction for TOF has been devised and is presented. The measured time resolution of 1.2 ns (FWHM) allowed for a signal-to-noise ratio increase of about 50% in phantoms of about 40 cm transaxial size, or a gain larger than 2 in noise equivalent counts (NEC). TOF reconstruction has shown the expected improvement in SNR, both in simulation and experimental data. First experimental results show two improvements of TOF reconstruction over conventional (non-TOF) reconstruction: a lower noise level and a better capability to resolve structures deep inside large objects.

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

    NASA Astrophysics Data System (ADS)

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

    2002-01-01

    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.

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

    SciTech Connect

    Sprenger, Lisa Lange, Adrian; Odenbach, Stefan

    2014-02-15

    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.

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

    NASA Technical Reports Server (NTRS)

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

    1971-01-01

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

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

    SciTech Connect

    1995-12-31

    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).

  20. Experimental and calculational results from the Spent Fuel Test-Climax

    SciTech Connect

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

    1982-10-14

    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.

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

    NASA Technical Reports Server (NTRS)

    Akin, David L.

    1987-01-01

    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.

  2. Introduction Random Walks Random Walks with Tabu Lists In Messages In Nodes Experimental Results Conclusion Routing Algorithms using Random Walks

    E-print Network

    Devismes, Stéphane

    Introduction Random Walks Random Walks with Tabu Lists In Messages In Nodes Experimental Results Conclusion Routing Algorithms using Random Walks with Tabu Lists Karine Altisen, Stéphane Devismes, Pascal;Introduction Random Walks Random Walks with Tabu Lists In Messages In Nodes Experimental Results Conclusion

  3. De-amortized Cuckoo Hashing: Provable Worst-Case Performance and Experimental Results

    E-print Network

    Arbitman, Yuriy; Segev, Gil

    2009-01-01

    Cuckoo hashing is a highly practical dynamic dictionary: it provides amortized constant insertion time, worst case constant deletion time and lookup time, and good memory utilization. However, with a noticeable probability during the insertion of n elements some insertion requires \\Omega(log n) time. Whereas such an amortized guarantee may be suitable for some applications, in other applications (such as high-performance routing) this is highly undesirable. Recently, Kirsch and Mitzenmacher (Allerton '07) proposed a de-amortization of cuckoo hashing using various queueing techniques that preserve its attractive properties. Kirsch and Mitzenmacher demonstrated a significant improvement to the worst case performance of cuckoo hashing via experimental results, but they left open the problem of constructing a scheme with provable properties. In this work we follow Kirsch and Mitzenmacher and present a de-amortization of cuckoo hashing that provably guarantees constant worst case operations. Specifically, for any ...

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

    NASA Technical Reports Server (NTRS)

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

    1977-01-01

    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.

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

    NASA Technical Reports Server (NTRS)

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

    1991-01-01

    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.

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

    E-print Network

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

    2013-01-01

    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...

  7. Rainfall estimation using microwave links. Results from an experimental setup in Luxembourg

    NASA Astrophysics Data System (ADS)

    Fenicia, Fabrizio; Matgen, Patrick; Pfister, Laurent

    2010-05-01

    Microwave links represent a valid alternative to traditional rainfall estimation methods. They are commonly used in mobile phone communication, and they constitute built-in widely distributed networks. Due to their ability of providing high temporal and spatial resolution measurements, their use is particularly suitable in urban settings. We here show results from an experimental setup in Luxembourg City, where two dual frequency links have been installed. The links cover a distance of about 4km, and measure power attenuation at 1 min. timestep. The links have been equipped with several recording raingauges, which measure rainfall in real-time communicating through a wireless connection. This set-up has been used to analyze in detail the mapping between attenuation and rainfall intensity, and gain insights into the potential accuracy of these instruments. In addition, we investigated the relation between rainfall and discharge response of the urban area of Luxembourg, which shows the potential utility of high frequency rainfall measurements for urban environments.

  8. An experimental study of stratospheric gravity waves - Design and preliminary results

    NASA Astrophysics Data System (ADS)

    Talagrand, O.; Ovarlez, H.

    1984-02-01

    The design of balloon-borne experimental apparatus for long-term gravitational-wave measurements in the stratosphere is reported, and preliminary results of a first test flight are presented. Two gondolas (each containing a pressure sensor; a temperature sensor; horizontal and vertical sonic anemometers; a fin equipped with crossed magnetometers; and data-processing, data-transmission, and control electronics) are suspended 100 and 300 m below a solar/terrestrial-IR-absorption-heated hot-air balloon drifting between altitudes 22 km (night) and 28 km (day); power is supplied by NiCd batteries recharged by solar cells. The path of the first flight, a circumnavigation beginning in Pretoria, South Africa and crossing South America and northern Australia, from December 11, 1982, to February 2, 1983 (when transmission ceased over southern Africa) is shown on a map, and sample data for a 36-h period are summarized in a graph.

  9. An aerodynamic analysis of the autogiro rotor with a comparison between calculated and experimental results

    NASA Technical Reports Server (NTRS)

    Wheatley, John B

    1935-01-01

    This report presents an extension of the autogiro theory of Glauert and Lock in which the influence of a pitch varying with the blade radius is evaluated and methods of approximating the effect of blade tip losses and the influence of reversed velocities on the retreating blades are developed. A comparison of calculated and experimental results showed that most of the rotor characteristics could be calculated with reasonable accuracy, and that the type of induced flow assumed has a secondary effect upon the net rotor forces, although the flapping motion is influenced appreciably. An approximate evaluation of the effect of parasite drag on the rotor blades established the importance of including this factor in the analysis.

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

    NASA Technical Reports Server (NTRS)

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

    1992-01-01

    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.

  11. An Experimental and Theoretical High Energy Physics Program

    SciTech Connect

    Shipsey, Ian

    2012-07-31

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

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

    NASA Astrophysics Data System (ADS)

    Figuera, P.

    2014-05-01

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

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

    SciTech Connect

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

    1998-10-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2011-10-01

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

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

    NASA Technical Reports Server (NTRS)

    Potapczuk, Mark G.; Berkowitz, Brian M.

    1989-01-01

    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.

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

    PubMed

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

    2012-06-01

    The growth of diffracting crystals from purified proteins is often a major bottleneck in determining structures of biological and medical interest. The PROSPERO web server, http://skuld.bmsc.washington.edu/prospero, is intended both to provide a means of organizing the potentially large numbers of experimental characterizations measured from such proteins, and to provide useful guidance for structural biologists who have succeeded in purifying their target protein but have reached an impasse in the difficult and poorly understood process of turning purified protein into well diffracting crystals. These researchers need to decide which of many possible rescue options are worth pursuing, given finite resources. This choice is even more crucial when attempting to solve high-priority but relatively difficult structures of eukaryotic proteins. The site currently uses the HyGX1 predictor, which was trained and validated on protein samples from pathogenic protozoa (eukaryotes) using results from six types of experiment. PROSPERO allows users to store, analyze and display multiple results for each sample, to group samples into projects, and to share results and predictions with collaborators. PMID:22675232

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

    NASA Technical Reports Server (NTRS)

    Potapczuk, Mark G.; Berkowitz, Brian M.

    1989-01-01

    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 for 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 past-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 measurements 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.

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

    SciTech Connect

    Lima da Silva, M.; Sauvage, E.; Brun, P.; Gagnoud, A.; Fautrelle, Y.; Riva, R.

    2013-07-01

    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)

  19. TRIDENT high-energy-density facility experimental capabilities and diagnostics

    SciTech Connect

    Batha, S. H.; Aragonez, R.; Archuleta, F. L.; Archuleta, T. N.; Benage, J. F.; Cobble, J. A.; Cowan, J. S.; Fatherley, V. E.; Flippo, K. A.; Gautier, D. C.; Gonzales, R. P.; Greenfield, S. R.; Hegelich, B. M.; Hurry, T. R.; Johnson, R. P.; Kline, J. L.; Letzring, S. A.; Loomis, E. N.; Lopez, F. E.; Luo, S. N.

    2008-10-15

    The newly upgraded TRIDENT high-energy-density (HED) facility provides high-energy short-pulse laser-matter interactions with powers in excess of 200 TW and energies greater than 120 J. In addition, TRIDENT retains two long-pulse (nanoseconds to microseconds) beams that are available for simultaneous use in either the same experiment or a separate one. The facility's flexibility is enhanced by the presence of two separate target chambers with a third undergoing commissioning. This capability allows the experimental configuration to be optimized by choosing the chamber with the most advantageous geometry and features. The TRIDENT facility also provides a wide range of standard instruments including optical, x-ray, and particle diagnostics. In addition, one chamber has a 10 in. manipulator allowing OMEGA and National Ignition Facility (NIF) diagnostics to be prototyped and calibrated.

  20. Experimental And Theoretical High Energy Physics Research At UCLA

    SciTech Connect

    Cousins, Robert D.

    2013-07-22

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

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

    NASA Technical Reports Server (NTRS)

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

    2006-01-01

    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.

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

    SciTech Connect

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

    2011-11-17

    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.

  3. Conservation of Mechanical and Electric Energy: Simple Experimental Verification

    ERIC Educational Resources Information Center

    Ponikvar, D.; Planinsic, G.

    2009-01-01

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

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

    NASA Technical Reports Server (NTRS)

    Manley, M. B.

    1980-01-01

    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.

  5. Low Dimensional Non-Crystallographic Metallic Nanostructures:. HRTEM Simulation, Models and Experimental Results

    NASA Astrophysics Data System (ADS)

    Rodríguez-López, J. L.; Montejano-Carrizales, J. M.; José-Yacamán, M.

    Modern nanoparticle research in the field of small metallic systems has confirmed that many nanoparticles take on some Platonic and Archimedean solids related shapes. A Platonic solid looks the same from any vertex, and intuitively they appear as good candidates for atomic equilibrium shapes. A very clear example is the icosahedral (Ih) particle that only shows {111} faces that contribute to produce a more rounded structure. Indeed, many studies report the Ih as the most stable particle at the size range r?20 Å for noble gases and for some metals. In this review, we report on the structure and shape of mono- and bimetallic nanoparticles in the wide size range from 1-300 nm. First, we present AuPd nanoparticles in the 1-2 nm size range that show dodecahedral atomic growth packing, one of the Platonic solid shapes that have not been identified before in this small size range for metallic particles. Next, with particles in the size range of 2-5 nm, we present an energetic surface reconstruction phenomenon observed also on bimetallic nanoparticle systems of AuPd and AuCu, similar to a re-solidification effect observed during cooling process in lead clusters. These binary alloy nanoparticles show the fivefold edges truncated, resulting in {100} faces on decahedral structures, an effect largely envisioned and reported theoretically, with no experimental evidence in the literature before. Next nanostructure we review is a monometallic system in the size range of ?5 nm that we termed the decmon. We present here some detailed geometrical analysis and experimental evidence that supports our models. Finally, in the size range of 100-300 nm, we present icosahedrally derived star gold nanocrystals which resembles the great stellated dodechaedron, which is a Kepler-Poisont solid. We conclude then that the shape or morphology of some mono- and bimetallic particles evolves with size following the sequence from atoms to the Platonic solids, and with a slightly greater particle's size, they tend to adopt Archimedean related shapes. If the particle's size is still greater, they tend to adopt shapes beyond the Archimedean (Kepler-Poisont) solids, reaching at the very end the bulk structure of solids. We demonstrate both experimentally and by means of computational simulations for each case that this structural atomic growth sequence is followed in such mono- and bimetallic nanoparticles.

  6. Preliminary Experimental Results on the Technique of Artificial River Replenishment to Mitigate Sediment Loss Downstream Dams

    NASA Astrophysics Data System (ADS)

    Franca, M. J.; Battisacco, E.; Schleiss, A. J.

    2014-12-01

    The transport of sediments by water throughout the river basins, from the steep slopes of the upstream regions to the sea level, is recognizable important to keep the natural conditions of rivers with a role on their ecology processes. Over the last decades, a reduction on the supply of sand and gravel has been observed downstream dams existing in several alpine rivers. Many studies highlight that the presence of a dam strongly modifies the river behavior in the downstream reach, in terms of morphology and hydrodynamics, with consequences on local ecology. Sediment deficit, bed armoring, river incision and bank instability are the main effects which affect negatively the aquatic habitats and the water quality. One of the proposed techniques to solve the problem of sediment deficit downstream dams, already adopted in few Japanese and German rivers although on an unsatisfactory fashion, is the artificial replenishment of these. Generally, it was verified that the erosion of the replenishments was not satisfactory and the transport rate was not enough to move the sediments to sufficient downstream distances. In order to improve and to provide an engineering answer to make this technique more applicable, a series of laboratory tests are ran as preparatory study to understand the hydrodynamics of the river flow when the replenishment technique is applied. Erodible volumes, with different lengths and submergence conditions, reproducing sediment replenishments volumes, are positioned along a channel bank. Different geometrical combinations of erodible sediment volumes are tested as well on the experimental flume. The first results of the experimental research, concerning erosion time evolution, the influence of discharge and the distance travelled by the eroded sediments, will be presented and discussed.

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

    PubMed Central

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

    2013-01-01

    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

  8. Experimental investigation of a packed bed thermal energy storage system

    NASA Astrophysics Data System (ADS)

    Cascetta, Mario; Cau, Giorgio; Puddu, Pierpaolo; Serra, Fabio

    2015-11-01

    In this work experimental investigations on a thermal energy storage system with a solid material as storage media and air as heat transfer fluid will be presented. The experimental test rig, installed at the DIMCM of the University of Cagliari, consists of a carbon steel tank filled with freely poured alumina beads that allows investigations of heat transfer phenomena in packed beds. The aim of this work is to show the influence of the operating conditions and physical parameters on thermocline formation and, in particular, the thermal behaviour of the thermal energy storage for repeated charging and discharging cycles. Better charging efficiency is obtained for lower values of mass flow rate and maximum air temperature and for increasing aspect ratio. A decreasing influence of the metal wall with continuous operation is also highlighted. In conclusion, the analysis focuses on the thermal hysteresis phenomenon, which causes degradation of the thermocline and the reduction of the energy that can be stored by the accumulator as the repeated number of cycles increases.

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

    SciTech Connect

    Leishear, R.

    2011-08-07

    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.

  10. A comparison of experimental results of soot production in laminar premixed flames

    NASA Astrophysics Data System (ADS)

    Caetano, Nattan R.; Soares, Diego; Nunes, Roger P.; Pereira, Fernando M.; Smith Schneider, Paulo; Vielmo, Horácio A.; van der Laan, Flávio Tadeu

    2015-05-01

    Soot emission has been the focus of numerous studies due to the numerous applications in industry, as well as the harmful effects caused to the environment. Thus, the purpose of this work is to analyze the soot formation in a flat flame burner using premixed compressed natural gas and air, where these quasi-adiabatic flames have one-dimensional characteristics. The measurements were performed applying the light extinction technique. The air/fuel equivalence ratiowas varied to assess the soot volume fractions for different flame configurations. Soot production along the flamewas also analyzed by measurements at different heights in relation to the burner surface. Results indicate that soot volume fraction increases with the equivalence ratio. The higher regions of the flamewere analyzed in order to map the soot distribution on these flames. The results are incorporated into the experimental database for measurement techniques calibration and for computational models validation of soot formation in methane premixed laminar flames, where the equivalence ratio ranging from 1.5 up to 8.

  11. Evaluation of in-vehicle HMI using occlusion techniques: experimental results and practical implications.

    PubMed

    Baumann, Martin; Keinath, Andreas; Krems, Josef F; Bengler, Klaus

    2004-05-01

    Despite the usefulness of new on-board information systems one has to be concerned about the potential distraction effects that they impose on the driver. Therefore, methods and procedures are necessary to assess the visual demand that is connected to the usage of an on-board system. The occlusion-method is considered a strong candidate as a procedure for evaluating display designs with regard to their visual demand. This paper reports results from two experimental studies conducted to further evaluate this method. In the first study, performance in using an in-car navigation system was measured under three conditions: static (parking lot), occlusion (shutter glasses), and driving. The results show that the occlusion-procedure can be used to simulate visual requirements of real traffic conditions. In a second study the occlusion method was compared to a global evaluation criterion based on the total task time. It can be demonstrated that the occlusion method can identify tasks which meet this criterion, but are yet irresolvable under driving conditions. It is concluded that the occlusion technique seems to be a reliable and valid method for evaluating visual and dialogue aspects of in-car information systems. PMID:15145282

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

    NASA Technical Reports Server (NTRS)

    Plumb, Robert C.

    1992-01-01

    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.

  13. RESEARCH RESULTS FORUM FOR RENEWABLE ENERGY TECHNOLOGY AND RESOURCE ASSESSMENTS

    E-print Network

    California at Davis, University of

    RESEARCH 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 Renewable Energy Center Assessment of Geothermal Resources In Under-served Regions #12;California Renewable

  14. Experimental studies of systematic multiple-energy operation at HIMAC synchrotron

    NASA Astrophysics Data System (ADS)

    Mizushima, K.; Katagiri, K.; Iwata, Y.; Furukawa, T.; Fujimoto, T.; Sato, S.; Hara, Y.; Shirai, T.; Noda, K.

    2014-07-01

    Multiple-energy synchrotron operation providing carbon-ion beams with various energies has been used for scanned particle therapy at NIRS. An energy range from 430 to 56 MeV/u and about 200 steps within this range are required to vary the Bragg peak position for effective treatment. The treatment also demands the slow extraction of beam with highly reliable properties, such as spill, position and size, for all energies. We propose an approach to generating multiple-energy operation meeting these requirements within a short time. In this approach, the device settings at most energy steps are determined without manual adjustments by using systematic parameter tuning depending on the beam energy. Experimental verification was carried out at the HIMAC synchrotron, and its results proved that this approach can greatly reduce the adjustment period.

  15. Position Tracking for a Nonlinear Underactuated Hovercraft: Controller Design and Experimental Results

    E-print Network

    Hespanha, João Pedro

    Position Tracking for a Nonlinear Underactuated Hovercraft: Controller Design and Experimental@ece.ucsb.edu Abstract-- This paper addresses the position tracking control problem of an underactuated hovercraft

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

    SciTech Connect

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

    2013-01-01

    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.

  17. Thermal Conductivity of Amorphous Geomaterials at Magmatic Temperatures: Review, Theory, and New Experimental Results.

    NASA Astrophysics Data System (ADS)

    Zayac, J. M.; Spera, F. J.

    2002-12-01

    Of all the transport properties of silicate melts and glasses, thermal conductivity remains the most poorly known despite its significance regarding both the transport of heat between magma and its surroundings and the petrologic evolution of open magmatic systems. The dearth of experimental conductivity data arises from the intrinsic difficulty of the experiments due to the confounding effects of convective heat transport and radiative transport, the latter which becomes important at high temperature (T). Although the volumetric absorption of radiation can be treated using the extinction coefficient, ?ex, defined as the inverse of the photon mean-free path, lph, the simultaneous treatment of the absorption, emission and scattering of radiation in a nonisothermal experiment may be complex. Additional complexity arises due to the dependence of lph on wavelength, ? . For example, for low-FeO silicate glass, lph = 0.2 m (?ex \\approx 5 m-1) at \\lambda = 0.4 ?m, whereas for \\lambda = 8 ?m, lph = 0.002 m (?ex \\approx 500 m-1). In natural systems, the optical thickness, ?OT \\equiv ?exL is large and the `thick-medium' approximation is justified since ?OT >> 1. Under this assumption the radiant conductivity (kR = 16/3\\sigmaSBn2T3lph) may be defined where the radiant heat flux is proportional to the temperature gradient as is the case for phonon conduction. We have undertaken a critical compilation of experimental results in order to separate the effects of the radiant (kR) and phonon (kP) conductivity in amorphous (molten and glassy) silicates and to understand the role of structural disorder on phonon conductivity. Because the radiative conductivity (kR) is ~ T3, experimental values of the `apparent' or `total' thermal conductivity (kT = kR + kP) plotted against T3 enable one to separate approximately the effects of radiation from phonon conduction in some instances. This approach enables one to estimate wavelength integrated extinction coefficients since the radiative heat flux is inversely proportional to the mean (wave-length integrated) extinction coefficient. In contrast, the phonon conductivity (kP) derives from two sources: phonon interaction and scattering due to structural disorder. Above the Debye temperature, Cp of a melt is constant; kp is ~ to the mean free path between atomic collisions (? ) which in turn varies inversely to the number of excited phonons (~ T). Hence, kP ~ 1/T. Near the Debye temperature, Cp decreases as T decreases and kP is less than expected from 1/T dependence. At very low temperature, even though few phonons are excited ? does not increase without limit because of structural disorder. Additionally, Cp ~ T3 and so kP is an increasing function of T. Finally, we present new experimental measurements of the thermal conductivity for supercooled amorphous geomaterials using a transient method and minimize radiant conductive effects using large volume (5x10-5 m3) samples (L ~0.04 m). The radiant contribution to the thermal conductivity is small in this apparatus for liquids characterized by mean (wave-length integrated) extinction coefficients > ~200 m-1.

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

    SciTech Connect

    Cantero, E. D.; Lantschner, G. H.; Arista, N. R.; Montanari, C. C.; Miraglia, J. E.; Behar, M.; Fadanelli, R. C.

    2011-07-15

    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.

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

    NASA Astrophysics Data System (ADS)

    Cantero, E. D.; Montanari, C. C.; Behar, M.; Fadanelli, R. C.; Lantschner, G. H.; Miraglia, J. E.; Arista, N. R.

    2011-07-01

    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.

  20. Experimental investigation of energy balance in plasma arc cutting process

    NASA Astrophysics Data System (ADS)

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

    2014-05-01

    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.

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

    NASA Technical Reports Server (NTRS)

    Carrier, Alain C.; Aubrun, Jean-Noel

    1993-01-01

    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.

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

    SciTech Connect

    Zangrando, M.; Zacchigna, M.; Bondino, F.; Finazzi, M.; Pardini, T.; Plate, M.; Rochow, R.; Cocco, D.; Parmigiani, F.

    2004-05-12

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

  3. CO2 utilization and storage in shale gas reservoirs: Experimental results and economic impacts

    DOE PAGESBeta

    Schaef, Herbert T.; Davidson, Casie L.; Owen, Antionette Toni; Miller, Quin R. S.; Loring, John S.; Thompson, Christopher J.; Bacon, Diana H.; Glezakou, Vassiliki Alexandra; McGrail, B. Peter

    2014-12-31

    Natural gas is considered a cleaner and lower-emission fuel than coal, and its high abundance from advanced drilling techniques has positioned natural gas as a major alternative energy source for the U.S. However, each ton of CO2 emitted from any type of fossil fuel combustion will continue to increase global atmospheric concentrations. One unique approach to reducing anthropogenic CO2 emissions involves coupling CO2 based enhanced gas recovery (EGR) operations in depleted shale gas reservoirs with long-term CO2 storage operations. In this paper, we report unique findings about the interactions between important shale minerals and sorbing gases (CH4 and CO2) andmore »associated economic consequences. Where enhanced condensation of CO2 followed by desorption on clay surface is observed under supercritical conditions, a linear sorption profile emerges for CH4. Volumetric changes to montmorillonites occur during exposure to CO2. Theory-based simulations identify interactions with interlayer cations as energetically favorable for CO2 intercalation. Thus, experimental evidence suggests CH4 does not occupy the interlayer and has only the propensity for surface adsorption. Mixed CH4:CO2 gas systems, where CH4 concentrations prevail, indicate preferential CO2 sorption as determined by in situ infrared spectroscopy and X-ray diffraction techniques. Collectively, these laboratory studies combined with a cost-based economic analysis provide a basis for identifying favorable CO2-EOR opportunities in previously fractured shale gas reservoirs approaching final stages of primary gas production. Moreover, utilization of site-specific laboratory measurements in reservoir simulators provides insight into optimum injection strategies for maximizing CH4/CO2 exchange rates to obtain peak natural gas production.« less

  4. Experimental and analytical results of a liquid-gas separator in microgravity

    NASA Astrophysics Data System (ADS)

    Best, Frederick; Ellis, Michael

    1999-01-01

    The microgravity phase separator designed and fabricated at Texas A&M University relies on centripetally driven buoyancy forces to form a gas-liquid vortex within a fixed, right-circular cylinder. Two phase flow is injected tangentially along the inner wall of this cylinder. Centripetal acceleration is produced from the intrinsic momentum of the resulting rotating flow and drives the buoyancy process. Gas travels under density gradients through the rotating liquid, eventually forming a gaseous core along the centerline of the cylinder. Gas core stability, the presence of liquid in the air line, and the presence of air in the liquid line determine whether a successful core results. To predict separation failure, these three factors were examined both analytically and empirically with the goal of determining what operating circumstances would generate them. The centripetal acceleration profile was determined from angular velocity measurements taken using a paddle wheel assembly. To aid in understanding the nature of the rotating flow, these results were compared to analytical results provided by solving simplified Navier-Stokes equations. The theoretical velocity profile indicated a linear dependence on radius, which with the experimental data agreed, although two distinctly different slopes were observed. As injection nozzle width increased, the difference between the slopes lessened. For all three nozzles tested, the discontinuity between the linear sections occurred at a radius of approximately 3.8 cm. The maximum centripetal acceleration generated by the flow was greatest for the 0.0635 cm wide, 0.516 cm tall injection nozzle and least for the 0.102 cm wide, 1.02 cm tall injection nozzle. The circumstances leading to carry-under are dictated by the relationship between axial and radial bubble transit times. To determine the radial and axial transit times, the radial velocity profile was solved analytically by relating the buoyancy and drag forces for a 0.0635 cm radius bubble. This velocity profile was then used to produce a numerical solution for the radial transit time. Volumetric flowrate analysis provided the axial velocity and bubble transit time. 33.4, 50.1, 66.8, and 83.5 cm3/s flowrates were tested and only the 33.4 cm3/s flowrate resulted in conditions which would lead to carry under.

  5. First Experimental Results Using Sparse Aperture Mask for Low Order Wavefront Sensing

    NASA Astrophysics Data System (ADS)

    Subedi, Hari; Zimmerman, Neil T.; Kasdin, N. Jeremy; Eldorado Riggs, A. J.

    2016-01-01

    We can determine the existence of life outside of earth by analyzing the spectra of exoplanets. Such direct imaging will provide the capability to thoroughly characterize an exoplanet's atmosphere. Direct imaging of exoplanets, however, has many technical challenges and difficulties: scattering and diffraction of light and the large difference in contrast, which is the ratio of brightness between the bright star and the dimmer planet. A coronagraph is an optical device that manipulates the diffraction of starlight and creates a region of high contrast (dark hole) where the dimmer planets can be seen. While in principle the level of contrast required for direct imaging of exoplanets can be achieved by stellar coronagraphic imaging, the resulting dark hole is highly sensitive to phase aberrations. In order to effectively suppress starlight for exoplanet imaging applications, low-order wavefront aberrations entering a coronagraph such as tip-tilt, defocus and coma must be determined and compensated for. A sparse-aperture mask (SAM) can be integrated in the telescopic imaging system to make precise estimate of low-order wavefront aberrations. In this technique, the starlight rejected by the coronagraph's focal plane stop is collimated to a relay pupil, where the mask forms an interference fringe pattern on a detector and the phase aberrations are inferred from this fringe pattern. At Princeton's High Contrast Imaging Lab (HCIL), we have numerically proved this concept and we are currently working on verifying it experimentally.

  6. Tubulin dipole moment, dielectric constant and quantum behavior: computer simulations, experimental results and suggestions

    E-print Network

    Mershin, A; Schüssler, H A; Nanopoulos, Dimitri V; Mershin, Andreas; Kolomenski, Alexandre A.; Schuessler, Hans A.; Nanopoulos, Dimitri V.

    2004-01-01

    We used computer simulation to calculate the electric dipole moments of the alpha and beta tubulin monomers and dimer and found those to be |palpha|=552D, |pbeta|=1193D and |palpha-beta|=1740D respectively. Independent surface plasmon resonance (SPR) and refractometry measurements of the high-frequency dielectric constant and polarizability strongly corroborated our previous SPR-derived results giving delta-n/delta-c ~1.800x10^-3 ml/mg. The refractive index of tubulin was measured to be n_tub ~2.90 and the high frequency tubulin dielectric constant kappa_tub ~8.41 while the high-frequency polarizability was found to be alpha_tub ~ 2.1x10^-33 C m^2/V. Methods for the experimental determination of the low-frequency p are explored as well as ways to test the often conjectured quantum coherence and entanglement properties of tubulin. Biobits, bioqubits and other applications to bioelectronics are discussed.

  7. Transport of silica colloids through unsaturated porous media: experimental results and model comparisons.

    PubMed

    Lenhart, John J; Saiers, James E

    2002-02-15

    We present results on the migration of silica colloids through laboratory columns packed with partially saturated quartz sand. The transport of the silica colloids responds to changes in the steady-state volumetric moisture content (theta) and for low theta depends on the wetting history of the sand pack prior to colloid injection. A mathematical model that incorporates a first-order rate law to simulate film straining and a second-order rate law to simulate partitioning at air-water interfaces closely describes colloid transport and mass transfer over the range of experimental conditions tested. The mass-transfer parameters of the model are sensitive to changes in both the level of water saturation and the flow rate. A semiempirical expression, based on a modification of film-straining theory, accounts for the observed variation in the first-order rate coefficient with changes in theta and average porewater velocity. Our work indicates that the presence of the air phase substantially influences porewater concentrations of mineral colloids in water-unsaturated media and that the kinetics of particle removal attributed to air-water boundaries reflects the contribution of multiple mass-transfer mechanisms. PMID:11878396

  8. Experimental Results from a 2 kW Brayton Power Conversion Unit

    NASA Astrophysics Data System (ADS)

    Hervol, David; Mason, Lee; Birchenough, Arthur

    2003-01-01

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

  9. Experimental Results From a 2kW Brayton Power Conversion Unit

    NASA Astrophysics Data System (ADS)

    Hervol, David; Mason, Lee; Birchenough, Arthur

    2003-01-01

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

  10. Bioimaging and biospectra analysis by means of independent component analysis: experimental results

    NASA Astrophysics Data System (ADS)

    Zhao, Qun; Langley, Jason; Lee, Joonsang; Abell, Justin; Zhao, Yiping

    2011-06-01

    Analysis of bioimaging and biospectra data has received increasingly attention in recent years. Here we will present two experimental results based on independent component analysis (ICA): differentiation of superparamagnetic iron oxide (SPIO) nanoparticles used as contrast agents in magnetic resonance imaging (MRI), and differentiation of mixed chemical analytes by surface-enhanced Raman scattering (SERS). The SPIO nanoparticles have been applied extensively as contrast agent in MRI for tracking of stem cells, targeted detection of cancer, due to its biocompatible and biodegradable features. For differentiation of SPIO from the background signal (e.g. interface between air and tissues), the signal voids from multiple sources makes the task very difficult. To solve this problem, we assume that the number of sensors corresponds to the number of acquisitions with different combinations of MR parameters, i.e., longitudinal and transverse relaxation times. For detection of chemical and biological analytes, the SERS approach has drawn more interest because of its high sensitivity. SERS spectra of mixed analytes were acquired at different locations of a silver nanorod array substrate. Due to the nonuniform diffusion and adsorption of the analytes, these spectra have been successfully used to identify the characteristic SERS spectrum of individual analytes. In both the MRI and SERS data, signal source separation (SPIO or mixed chemical analytes from background signal) was performed on a pixel by pixel basis. The ICA was performed by a spatial analysis using the fast ICA method.

  11. Non-Shock Initiation Model for Plastic Bonded Explosive PBXN-5 and Cast Explosive: Experimental Results

    NASA Astrophysics Data System (ADS)

    Anderson, Mark; Todd, Steven; Caipen, Terry; Jensen, Charlie; Hughs, Chance

    2009-06-01

    A damage initiated reaction (DMGIR) computational model is being developed for the CTH shock physics code to predict the response of an explosive to non-shock mechanical insults. The distinguishing feature of this model is the introduction of a damage variable, which relates the evolution of damage to the initiation of reaction in the explosive, and its growth to detonation. The DMGIR model is a complement to the History Variable Reactive Burn (HVRB) model embedded in the current CTH code. Specifically designed experiments are supporting the development, implementation, and validation of the DMGIR numerical approach. PBXN-5 was the initial explosive material used experimentally to develop the DMGIR model. This explosive represents a family of plastically bonded explosives with good mechanical strength and rigid body properties. The model has been extended to cast explosives represented by Composition B. Furthermore, the DMGIR model will extended to predict results of non-shock mechanical insults for moldable plastic explosives such as C4 and PrimaSheet.

  12. Analytical model for a pulse tube cryocooler bellows phase shifter and experimental results

    NASA Astrophysics Data System (ADS)

    Cheadle, Michael; Nellis, Gregory; Klein, Sanford

    2012-06-01

    Losses within a pulse tube cryocooler (PTC) are dominated by regenerator losses that scale directly with the magnitude of the mass flow rate within the regenerator. Therefore, in order to maximize PTC performance it is necessary to minimize the ratio of the mass flow rate in the regenerator to the acoustic power. This is accomplished by controlling the phase between the mass flow and the pressure with a phase shifting device installed at the warm end of the pulse tube. The most common device, the inertance tube, has significant disadvantages including limited achievable phase angles and large mass and volume. Also, once installed the inertance tube is not tunable. It has been proposed that the inertance tube be replaced with a hybrid mechanical/electrical phase shifting system. The damping for this system is provided by an eddy current damper and can be controlled via an applied external magnetic field that provides active real-time phase control. This paper presents an analytical model of a bellows phase shifting mechanism for a PTC. The model is used to determine properties of the phase shifting mechanism (volume, mass, spring constant, damping force, etc.) based on typical PTC operating conditions. Initial experimental results are also presented.

  13. Design and experimental results for a compact laser printer optical system with MEMS scanning mirror

    NASA Astrophysics Data System (ADS)

    Suzuki, Takatoshi; Seki, Daisuke; Fujii, Shuichi; Mukai, Yukihiro

    2010-02-01

    There are many features expected by printer users, which include high resolution, low price, compact size, color, high speed printing and so on. Laser printers generally utilize a polygon mirror as a reflector in their optical configurations, but the usual size of the polygon mirror prevents laser scanning unit from being made much smaller. We have been conducting research on techniques which can contribute to reducing the optical unit size. Although oscillating mirror made with MEMS technology enables the system to be compact, it requires a sophisticated optical design having an increased number of constraints due to the change in angular velocity which varies depending on the orientation of the mirror, while the polygon mirror allows the scanning with constant speed. Using a small MEMS mirror is one of the critical issues concerning the reduction of cost. We have successfully resolved all the challenges listed above by using high-precision free-form optical surfaces and an optical layout making efficient use of 3D space. Our techniques can make the unit size much smaller and reduce the price. The optical path is designed to have a ray passing through a lens twice. We report both theoretical and experimental results for this system.

  14. A Computational Model for Predicting Experimental RNA Nearest-Neighbor Free Energy Rankings: Inosine•Uridine Pairs.

    PubMed

    Jolley, Elizabeth A; Lewis, Michael; Znosko, Brent M

    2015-10-16

    A computational model for predicting RNA nearest neighbor free energy rankings has been expanded to include the nonstandard nucleotide inosine. The model uses average fiber diffraction data and molecular dynamic simulations to generate input geometries for Quantum mechanic calculations. This resulted in calculated intrastrand stacking, interstrand stacking, and hydrogen bonding energies that were combined to give total binding energies. Total binding energies for RNA dimer duplexes containing inosine were ranked and compared to experimentally determined free energy ranks for RNA duplexes containing inosine. Statistical analysis showed significant agreement between the computationally determined ranks and the experimentally determined ranks. PMID:26525429

  15. Initial Experimental Results of a Laboratory Mini-Magnetosphere for Astronaut Protection

    NASA Astrophysics Data System (ADS)

    Bamford, R. A.; Bingham, R.; Gibson, K.; Thornton, A.; Bradford, J.; Hapgood, M.; Gargate, L.; Silva, L.; Norberg, C.; Todd, T.; Wilson, H.; Stamper, R.

    2007-12-01

    Radiation is a major scientific and technological challenge for manned missions to Mars. With an interplanetary flight time of months to years there is a high probability of Solar Energetic Particle events during the flight. Radiation damage to human tissue could result in acute sickness or death of the occupants of an unprotected spacecraft. Thus there is much interest in techniques to mitigate the effects of these events and of the exposure to cosmic rays. The experimental and modelling work presented here concerns one of several innovative "Active Shield" solutions being proposed [1]. The idea of generating an artificial magnetosphere to recreate the protective shield of the Earth's magnetic field for space craft travelling to the Moon or Mars was considered seriously in the 1960's during the Apollo era. With most of the space agencies around the world setting their sights returning to the Moon and then on to Mars, the idea of some sort of active field solution is experiencing a resurgence. Results from the laboratory experiment to determine the effectiveness of a mini-magnetosphere barrier to be able to expel a flowing energetic "solar wind" plasma will be presented. This is compared to a 3D hybrid simulation code that has been successfully compared to other astrophysical situations e.g. AMPTE artificial comet releases [2]. The experiment and modelling comparisons will demonstrate the scalability between the laboratory and astrophysical scale. [1] Adams, J.H. et al., "Revolutionary Concepts of Radiation Shielding for Human Exploration of Space", NASA/TM- 2005-213688, March 2005. [2] Gargate, L.; Bingham, R.; Fonseca, R. A.; Silva, L. O., "dHybrid: A massively parallel code for hybrid simulations of space plasmas", Computer Physics Communications, Volume 176, Issue 6, Pages 419-425, 15 March 2007, doi:10.1016/j.cpc.2006.11.013

  16. Experimental studies of pion-nucleus interactions at intermediate energies

    SciTech Connect

    Not Available

    1991-12-31

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

  17. Acoustic propagation in the Hudson River Estuary: Analysis of experimental measurements and numerical modeling results

    NASA Astrophysics Data System (ADS)

    Radhakrishnan, Sreeram

    Underwater intrusion detection is an ongoing security concern in port and harbor areas. Of particular interest is to detect SCUBA divers, unmanned underwater vehicles and small boats from their acoustic signature. A thorough understanding of the effects of the shallow water propagating medium on acoustic signals can help develop new technologies and improve the performance of existing acoustic based surveillance systems. The Hudson River Estuary provides us with such a shallow water medium to conduct research and improve our knowledge of shallow water acoustics. Acoustic propagation in the Hudson River Estuary is highly affected by the temporal and spatial variability of salinity and temperature due to tides, freshwater inflows, winds etc. The primary goal of this research is to help develop methodologies to predict the formation of an acoustic field in the realistic environment of the lower Hudson River Estuary. Shallow water high-frequency acoustic propagation experiments were conducted in the Hudson River near Hoboken, New Jersey. Channel Impulse Response (CIR) measurements were carried out in the frequency band from 10 to 100 kHz for distances up to 200 meters in a water depth of 8-10 meters which formed the basis for experimental Transmission Loss (TL). CIR data was also utilized to demonstrate multi-path propagation in shallow water. Acoustic propagation models based on Ray Theory and Parabolic Equation methods were implemented in the frequency band from 10 to 100 kHz and TL was estimated. The sound velocity profiles required as input by acoustic propagation models were calculated from in-situ measurements of temperature, salinity and depth. Surface reflection loss was obtained from CIR data and incorporated into the acoustic propagation models. Experimentally obtained TL was used to validate the acoustic model predictions. An outcome of this research is an operational acoustic transmission loss (TL) forecast system based on the existing, Stevens New York Harbor observation and prediction system (NYHOPS) which provides 48-hour forecasts of salinity and temperature profiles. Initial results indicate that the NYHOPS forecast of sound speed profiles used in conjunction with the acoustic propagation model is able to make realistic forecasts of TL in the Hudson River Estuary.

  18. Wageningen Urban Rainfall Experiment 2014 (WURex14): Experimental Setup and First Results

    NASA Astrophysics Data System (ADS)

    Uijlenhoet, R.; Overeem, A.; Leijnse, H.; Hazenberg, P.

    2014-12-01

    Microwave links from cellular communication networks have been shown to be able to provide valuable information concerning the space-time variability of rainfall. In particular over urban areas, where network densities are generally high, they have the potential to complement existing dedicated infrastructure to measure rainfall (gauges, radars). In addition, microwave links provide a great opportunity for ground-based rainfall measurement for those land surface areas of the world where gauges and radars are generally lacking, e.g. Africa, Latin America, and large parts of Asia. Such information is not only crucial for water management and agriculture, but also for instance for ground validation of space-borne rainfall estimates such as those provided by the recently launched core satellite of the GPM (Global Precipitation Measurement) mission. WURex14 is dedicated to address several errors and uncertainties associated with such quantitative precipitation estimates in detail. The core of the experiment is provided by two co-located microwave links installed between two major buildings on the Wageningen University campus, approximately 2 km apart: a 38 GHz commercial microwave link, kindly provided to us by T-Mobile NL, and a 38 GHz dual-polarization research microwave link from RAL. Transmitting and receiving antennas have been attached to masts installed on the roofs of the two buildings, about 30 m above the ground. This setup has been complemented with a Scintec infrared Large-Aperture Scintillometer, installed over the same path, as well as a Parsivel optical disdrometer, located close to the mast on the receiving end of the links. During the course of the experiment, a 26 GHz RAL research microwave link was added to the experimental setup. Temporal sampling of the received signals was performed at a rate of 20 Hz. In addition, two time-lapse cameras have been installed on either side of the path to monitor the wetness of the antennas as well as the state of the atmosphere. Approximately halfway along the link path a rain gauge from the KNMI operational network is located. Finally, data is available from several commercial microwave links in the vicinity of the experimental setup, as well as from the KNMI weather radars. We report on the first results from this experiment, collected during the Summer and Fall of 2014.

  19. Wageningen Urban Rainfall Experiment 2014 (WURex14): Experimental Setup and First Results

    NASA Astrophysics Data System (ADS)

    van Leth, Thomas; Uijlenhoet, Remko; Overeem, Aart; Leijnse, Hidde; Hazenberg, Pieter

    2015-04-01

    Microwave links from cellular communication networks have been shown to be able to provide valuable information concerning the space-time variability of rainfall. In particular over urban areas, where network densities are generally high, they have the potential to complement existing dedicated infrastructure to measure rainfall (gauges, radars). In addition, microwave links provide a great opportunity for ground-based rainfall measurement for those land surface areas of the world where gauges and radars are generally lacking, e.g. Africa, Latin America, and large parts of Asia. Such information is not only crucial for water management and agriculture, but also for instance for ground validation of space-borne rainfall estimates such as those provided by the recently launched core satellite of the GPM (Global Precipitation Measurement) mission. WURex14 is dedicated to address several errors and uncertainties associated with such quantitative precipitation estimates in detail. The core of the experiment is provided by two co-located microwave links installed between two major buildings on the Wageningen University campus, approximately 2 km apart: a 38 GHz commercial microwave link, kindly provided to us by T-Mobile NL, and a 38 GHz dual-polarization research microwave link from RAL. Transmitting and receiving antennas have been attached to masts installed on the roofs of the two buildings, about 30 m above the ground. This setup has been complemented with a Scintec infrared Large-Aperture Scintillometer, installed over the same path, as well as a Parsivel optical disdrometer, located close to the mast on the receiving end of the links. During the course of the experiment, a 26 GHz RAL research microwave link was added to the experimental setup. Temporal sampling of the received signals was performed at a rate of 20 Hz. In addition, two time-lapse cameras have been installed on either side of the path to monitor the wetness of the antennas as well as the state of the atmosphere. Approximately halfway along the link path a rain gauge from the KNMI operational network is located. Finally, data is available from several commercial microwave links in the vicinity of the experimental setup, as well as from the KNMI weather radars. We report on the first results from this experiment, collected during the Summer and Fall of 2014.

  20. Robotic Exploration and Science in Pits and Caves: Results from Three Years and Counting of Analog Field Experimentation

    NASA Astrophysics Data System (ADS)

    Wong, U. Y.; Whittaker, W. L.

    2015-10-01

    Robots are poised to access, investigate, and model planetary caves. We present the results of a multi-year campaign to develop robotic technologies for this domain, anchored by the most comprehensive analog field experimentation to date.

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

    NASA Technical Reports Server (NTRS)

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

    1985-01-01

    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.

  2. NASA/Pratt and Whitney experimental clean combustor program: Engine test results

    NASA Technical Reports Server (NTRS)

    Roberts, R.; Fiorentino, A. J.; Greene, W.

    1977-01-01

    A two-stage vorbix (vortex burning and mixing) combustor and associated fuel system components were successfully tested in an experimental JT9D engine at steady-state and transient operating conditions, using ASTM Jet-A fuel. Full-scale JT9D experimental engine tests were conducted in a phase three aircraft experimental clean combustor program. The low-pollution combustor, fuel system, and fuel control concepts were derived from phase one and phase two programs in which several combustor concepts were evaluated, refined, and optimized in a component test rig. Significant pollution reductions were achieved with the combustor which meets the performance, operating, and installation requirements of the engine.

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

    NASA Astrophysics Data System (ADS)

    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

    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.

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

    SciTech Connect

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

    2012-07-01

    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.

  5. EXPERIMENTAL RESULTS ON TRAPPING A GUN PLASMA IN A TOROIDAL MAGNETIC CUSP EXPERIMENT

    SciTech Connect

    Pincosy, P.A.; Myers, B.R.; Levine, M.A.; Feinberg, B.; Niland, R.A.; Soroka, L.

    1983-11-01

    A start-up method for producing a plasma in the bi-cusp field configuration of a toroidal magnetic cusp (TORMAC) is described. The method uses the radial injection and trapping of a toroidal gun plasma. Measurements of an injected plasma with a velocity of 17 {micro}sec{sup -1} and 4.5 x 10{sup 18} particles is presented. The plasma was observed to be stopped and trapped in an equilibrium position. A well-defined outer boundary remained stationary for 20 {micro}sec. Particle flux distribution emanating from the cusp field lines defined a sheath having a width of 1-1.5 ion gyroradii in the poloidial field. This translates to a narrow outer boundary and a broad inner boundary based on the gradient of the poloidial field at the two radial positions. Measurements of Thomson scattering and interferometry give a T{sub e} of 15eV, a 15 {micro}sec density decay time, and a 5 {micro}sec energy decay time. These results show that this injection and trapping method is successful, and thus a higher gun plasma energy combined with a flux conserving barrier may lead to higher temperatures for testing containment in TORMAC.

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

    SciTech Connect

    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.

    2014-12-15

    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?5×10{sup 7} cm/s and the radial convergence ratio is between 10 and 20.

  7. Effect of Hydrodynamics on Particle Transport in Saturated Fractures: Experimental and Simulation Results

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

    Approximately one third of Canadians and Americans use groundwater as their source of drinking water. Porous media aquifers typically provide significant filtration of particulate contaminants (e.g., viruses, bacteria, protozoa). Fractured media, however, does not provide the same degree of filtration, and in fact often acts as a pathway for particulates to migrate, typically at much greater velocities than in porous media. Fractured aquifers, therefore, are significantly more vulnerable to particulate contamination than unconsolidated porous media. Thus, understanding in the mechanisms of particle migration and retention in fractures is important for the protection and management of these drinking water sources. The purpose of this work was to investigate the role of hydrodynamics on particle transport in saturated, variable aperture fractures. A 2D fracture was randomly generated with an average aperture of approximately 2mm. The fracture was inscribed into pieces of poly(methyl methacrylate), thus creating a pseudo-2D fracture (the xy fracture domain is invariant in z). Transport experiments using fluorescent microspheres (0.05 um, 0.5 um, and 0.75 um) were performed at 2.6 m/day, 26 m/day and 113 m/day and the resulting breakthrough curves were measured. These breakthrough curves included various shoulders and artifacts that were repeatable and could be used to evaluate the quality of a model. COMSOL Multiphysics, was used to generate an average flow field through the 2D fracture by numerically solving the steady-state Navier-Stokes equation. In order to have a 3D realization of the flow field, a parabolic flow regime was assumed in the z-axis and used to scale the average flow field. Random walk particle tracking was utilized to generate breakthrough curves; however, the Brownian motion and local fluid shear mechanisms needed to be considered in addition to the standard movement of particles via the local flow field in order to appropriately model the experimental results. These results suggest that local hydrodynamics are important in defining the transport of particles through a fracture. We plan to discuss further applications, general statistics, and particle retention in fractures due to hydrodynamics and ultimately the role of fracture geometry in particle transport.

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

    NASA Astrophysics Data System (ADS)

    Karato, S.; Dai, L.

    2013-12-01

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

  9. Coherent optical receiver for PPM signals received through atmospheric turbulence: performance analysis and preliminary experimental results

    NASA Technical Reports Server (NTRS)

    Munoz Fernandez, M.; Vilnrotter, V. A.

    2004-01-01

    The performance of a coherent free-space optical communications system is investigated. Bit Error Rate (BER) performance is analyzed, and laboratory equipment and experimental setup used to carry out these experiments at JPL are described.

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

    NASA Astrophysics Data System (ADS)

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

    2009-11-01

    An experimental investigation of two jet noise reduction techniques is presented. These techniques are currently employed on commercial aircraft, and we now apply them to a convergent-divergent nozzle with geometry typical of military aircraft. The acoustic effects of chevrons and fluidic injection on chevrons are quantified by Near-Field and Far-Field acoustic measurements. Experimental tests are shown for overexpanded, underexpanded, and on design nozzle pressure ratios to simulate the entire flight envelope of a military aircraft. In nearly all cases chevrons are shown to reduce noise and eliminate screech tones. Adding fluidic injection to chevrons shows additional far-field noise reduction for underexpanded conditions. This presentation is the experimental portion of a joint numerical/experimental program.

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

    NASA Technical Reports Server (NTRS)

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

    1976-01-01

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2012-12-01

    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.

  13. Regional Assesssment and Monitoring of Teh Carbon Balance Within Europe (recab): Experimental Strategy and Mesoscale Modeling Preliminary Results

    NASA Astrophysics Data System (ADS)

    Dolman, H.; de Martino, B.; Gioli, B.; Hutjes, R. W. A.; Lindroth, A.; Miglietta, F.; Millan, M. M.; Sanz, M. J.; Schumacher, M.

    The aim of RECAB project (EU project EVK2-CT-1999-00034) is to quantify the contribution of fossil fuel and biospheric sources and sinks of CO2 in Europe to the atmospheric concentration at the regional scale by using a generic coupled bio- sphere atmosphere modelling and experimental approach. To achieve this, a coupled mesoscale-land surface model incorporating the biosphere is being developed; a flux aircraft for low flying purposes was set up and is being used for the regional flux mea- surements (Sky Arrow 650 TCN version ERA); and a system for collecting flask sam- ples to determine gas concentrations (CH4, CO2 and N2O) and isotope ratios (ä13C and ä18O in CO2) is operative on small aircrafts is also set up. The ERA represents the first attempt in Europe to measure surface mass and energy fluxes using airborne eddy covariance. The ERA uses the Best Aircraft Turbulence Probe (BAT) probe that is being developed by NOAA and Airborne Research Australia (ARA). The BAT in- corporates a pressure sphere housing with a synthesis of differential GPS (DGPS), solid-state sensors, and electronic and aerodynamic technology to allow high fidelity turbulence measurements from any aeroplane. CO2 and water vapour concentrations are measured using a fast response open-path infrared gas analyser (LiCor7500) which is mounted on the aircraft nose. For the flask sampling air probes are taken as twin pairs at different flight levels. During the flights the track is recorded by GPS and meteorological parameters as also the CO2 concentration (LiCor6251) are measured online to employ a CBL-Budget-Method as another approach. Additional air probes are taken with a similar sampling unit at ground level within sites of characteristic land use for gas concentration analyses and isotope ratio determination. Three summer (Valencia, Spain; Hainich, Germany; Norunda, Sweden) and three winter (Valencia; 1 Hainich; Loobos, Netherlands) experimental campaigns were successfully executed. Experimental deployments and preliminary experimental an modelling results show- ing different synoptic weather conditions are available, including CO2 vertical profiles (isotopes and concentration), horizontal flux transects and other relevant parameters. Also measurements from eddy flux towers in the measurement areas. are available, and in addition various ABL probes (RASS, SODAR, tethered balloons). 2

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

    NASA Astrophysics Data System (ADS)

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

    2010-05-01

    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.

  15. Incorporation of OH in olivine at high pressure: new experimental results

    NASA Astrophysics Data System (ADS)

    Mosenfelder, J. L.; Deligne, N. I.; Asimow, P. D.; Rossman, G. R.

    2002-12-01

    Numerous studies of natural and experimentally hydrated samples show that olivine can incorporate substantial amounts of hydrogen at high pressures, which has important implications for the rheology, melting behavior and transport properties of the mantle. We have conducted new experiments to further investigate the incorporation of hydroxide in olivine at high pressures (2-10 GPa) and temperatures (1100-1300°C) and varying oxygen fugacity and silica activity. In contrast to previous experiments, we calculate the concentration of OH in olivine by integrating the total absorbance from three FTIR spectra polarized in orthogonal directions and applying the new calibration of Bell et al. (in press). This procedure is inherently more accurate than the use of nominally unpolarized spectra and the generic calibration of Paterson (1982). We have used both fine-grained natural Fo90 olivine powders and oriented single crystals (500 x 600 x 700 ?m) as starting materials. Water in the experiments is provided by dehydration of talc and/or brucite, the ratio of which is chosen in order to establish equilibrium with either orthopyroxene or (Mg,Fe)O. In some experiments, Ni + NiO or Re + ReO is also added to the charge in order to influence the oxygen fugacity of the experiment. In experiments using fine-grained powders at 1150-1300°C, significant grain growth takes place, resulting in grain diameters up to ~300 ?m; suitably oriented grains for polarized spectroscopy are then identified using a variety of techniques. Our preliminary results include the following: 1) The spectra in all samples are dominated by sharp peaks in the range of ~3650-3400 cm-1, regardless of estimated silica activity. This is consistent with most previous experimental studies and, broadly speaking, with the spectra of most natural olivines. 2) The shapes of the spectra in all our samples are similar regardless of whether grain growth occurred under hydrous conditions or diffusion of H into existing large crystals took place. This strongly suggests that the mechanism of incorporation is identical in both cases. However, in experiments at 1100°C, large single crystals exhibit strongly zoned concentration profiles, consistent with the most recent diffusion data for OH in olivine (Kohlstedt and Mackwell, 1998). This complicates interpretation of these experiments and casts uncertainty on interpretation of previous experiments that used the same technique. 3) Comparison of experiments using Ni-NiO or Re-ReO as buffers shows little effect of oxygen fugacity (in this range, ~2 log units in fO2) on either concentration or incorporation mechanism. 4) Concentrations measured in the samples that used fine-grained starting materials are 2.5-3 times higher than the previous estimates for OH solubility measured by Kohlstedt et al. (1996). This difference is primarily attributed to use of the new calibration and measurement of polarized spectra. We are conducting further experiments to understand more quantitatively the roles of silica activity, oxygen fugacity, and starting point defect structure on incorporation of OH in olivine.

  16. Preliminary Experimental Results on a Volcanic Meimechite Composition From Meymecha, Siberia

    NASA Astrophysics Data System (ADS)

    Elkins-Tanton, L. T.; Jewell, J.; Hess, P. C.

    2003-12-01

    Ultramafic lavas, predominantly meimechites, form an approximately 1400 m stack at the top of the Siberian flood basalt section in the Maymecha-Kotuy region (see in particular Fedorenko and Czamanske, 1997). The meimechite stratigraphy correlates with an area above the top of the Siberian flood basalt stratigraphic sections in Noril'sk, Tunguska, and Putorana. Meimechites are exceptionally high in magnesium and iron (up to 38 wt% and 17 wt% respectively), low in silica (40 to 42 wt%). Although the major element compositions of the meimechite melt inclusions measured by Sobolev et al. (1991) plot on the same trends as the bulk rocks, the alkali contents of the melt inclusions are systematically higher than the lava compositions, suggesting that the lavas have lost alkalis. The majority of whole rock compositions have sodium to potassium ratios below one, while the majority of melt inclusions have ratios above one, indicating loss of sodium. With the higher alkali content, up to 5 wt% sodium plus potassium in the melt inclusions, the melt inclusion liquids no longer qualify as meimechites under the new IUGS definition, but rather as foidites. Further analysis of major element trends indicates that, in agreement with Arndt et al. (1995) and others, compositions with MgO contents of approximately 25% represent liquid compositions, and we conclude that lower magnesium compositions are the results of olivine fractionation, while higher magnesium composition have accumulated olivine. Preliminary one-atmosphere and piston-cylinder experiments have been performed on a synthetic analog of a meimechite composition obtained from an olivine melt inclusion, with 26.9 wt% MgO, 8.2 wt% CaO, and 40.2 wt% silica. The experimental composition, with an Mg# of 78.3, has a nearly identical major element composition as whole rock compositions, except that the melt inclusion has higher alkali content, at about 3 wt% sodium oxide plus potassium oxide. The preliminary experiments show that the composition's liquidus at one atmosphere is at about 1450 degrees C, and at 1 GPa the liquidus lies at about 1550 degrees C. Olivine and spinel are stable at the liquidus from one atmosphere to 1 GPa, and pyroxene appears at one atmosphere at about 1250 degrees C, after approximately 200 degrees of olivine crystallization. While the roles of hydrous fluids and magma mixing have yet to be determined, it can be shown that a number of the lavas erupted within their olivine stability fields, with pyroxene only in the groundmass, and from our preliminary experimental results this constrains the eruption temperature to between 1250 and 1450 degrees C. The high magnesium content of these lavas have lead some workers to conclude that they are the definitive plume signature, arguing that they could only have been formed by very deep and hot melting. Others have suggested that they are olivine cumulates, supported by the large, abundant olivine grains in the lavas, because the linear compositional trends in major elements of all the meimechite bulk compositions are consistent with an accumulation or loss of olivine. The high concentration of incompatible elements of the lavas also may suggest either a lithospheric component, a very small degree of mantle melting, or possibly magma mixing. The very high liquidus temperature for this composition is a strong contraint on processes of formation for the Siberian flood basalts, and as experiments are performed at higher temperatures, suggestions for the mantle source lithology will be discovered.

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

    USGS Publications Warehouse

    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, Jean-Francois; Mengelkamp, H.-T.; Mitchell, Ken; 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

    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.

  18. Promoting walking to school: results of a quasi?experimental trial

    PubMed Central

    McKee, Rosie; Mutrie, Nanette; Crawford, Fiona; Green, Brian

    2007-01-01

    Study objective To assess the impact of a combined intervention on children's travel behaviour, stage of behavioural change and motivations for and barriers to actively commuting to school. Design A quasi?experimental trial involving pre? and post?intervention mapping of routes to school by active and inactive mode of travel and surveys of “stage of behaviour change” and motivations for and barriers to actively commuting to school. Intervention The intervention school participated in a school?based active travel project for one school term. Active travel was integrated into the curriculum and participants used interactive travel?planning resources at home. The control school participated in before and after measurements but did not receive the intervention. Setting Two primary schools in Scotland with similar socioeconomic and demographic profiles. Participants Two classes of primary 5 children and their families and teachers. Main results Post intervention, the mean distance travelled to school by walking by intervention children increased significantly from baseline, from 198 to 772?m (389% increase). In the control group mean distance walked increased from 242 to 285?m (17% increase). The difference between the schools was significant (t (38) ?=??4.679, p<0.001 (95% confidence interval ?315 to ?795?m)). Post intervention, the mean distance travelled to school by car by intervention children reduced significantly from baseline, from 2018 to 933?m (57.5% reduction). The mean distance travelled to school by car by control children increased from baseline, from 933 to 947?m (1.5% increase). The difference in the change between schools was significant (t (32) ?=?4.282, p<0.001 (95% confidence interval 445 to 1255?m)). Conclusions Intervention was effective in achieving an increase in the mean distance travelled by active mode and a reduction in the mean distance travelled by inactive mode on school journey. PMID:17699538

  19. RESEARCH RESULTS FORUM FOR RENEWABLE ENERGY TECHNOLOGY AND RESOURCE ASSESSMENTS

    E-print Network

    California at Davis, University of

    RESEARCH 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;Biomass/MSW Gap operate as close-coupled combustion ("two-step oxidation") but ­ advanced systems in development Bill

  20. Development of Revised Energy Standards for Texas Buildings: Preliminary Results 

    E-print Network

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

    1988-01-01

    OF REVISED ENERGY STANDARDS FOR TEXAS BUILDINGS: PRELIMINARY RESULTS B. D. HUNN, J. W. JONJlS, and S. C. SILVER Center for Energy Studies The University of Texas at Austin Amtin, Texas In 1977, the State of Texas published a two- part Energy...

  1. Experimental High Energy Physics Brandeis University Final Report

    SciTech Connect

    Blocker, Craig A.; Bensinger, James; Sciolla, Gabriella; Wellenstein, Hermann

    2013-07-26

    During the past three years, the Brandeis experimental particle physics group was comprised of four faculty (Bensinger, Blocker, Sciolla, and Wellenstein), one research scientist, one post doc, and ten graduate students. The group focused on the ATLAS experiment at LHC. In 2011, the LHC delivered 5/fb of pp colliding beam data at a center-of-mass energy of 7 TeV. In 2012, the center-of-mass energy was increased to 8 TeV, and 20/fb were delivered. The Brandeis group focused on two aspects of the ATLAS experiment -- the muon detection system and physics analysis. Since data taking began at the LHC in 2009, our group actively worked on ATLAS physics analysis, with an emphasis on exploiting the new energy regime of the LHC to search for indications of physics beyond the Standard Model. The topics investigated were Z' -> ll, Higgs -> ZZ* -. 4l, lepton flavor violation, muon compositeness, left-right symmetric theories, and a search for Higgs -> ee. The Brandeis group has for many years been a leader in the endcap muon system, making important contributions to every aspect of its design and production. During the past three years, the group continued to work on commissioning the muon detector and alignment system, development of alignment software, and installation of remaining chambers.

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

    SciTech Connect

    Lambert, L.D.; Parks, M.B.

    1995-10-01

    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.

  3. Chlorine Stable Isotope Composition of Altered Oceanic Crust: Empirical and Experimental Results

    NASA Astrophysics Data System (ADS)

    Barnes, J.; Gardner, J. E.

    2010-12-01

    Chlorine is an excellent geochemical tracer of fluid-rock interactions because it strongly partitions into the aqueous fluid phase. Chlorine can be used to study the migration of fluids in the crustal environment, volatiles in subduction zones, and the interaction between oceanic lithosphere and seawater-derived hydrothermal fluids. Cl is only a useful tracer, however, if 1) the ?37Cl values of potential chlorine reservoirs and 2) the relevant equilibrium chlorine isotope fractionation factors are both well constrained. Poor constraints on both 1 and 2 for altered oceanic crust (AOC) severely limit our understanding of the global Cl cycle. Here we present ?37Cl values of AOC sampled by the Ocean Drilling Program (ODP). Samples from the Southwest Indian Ridge (ODP Hole 735B) have ?37Cl values ranging from -0.2 to +0.2‰ (error < ± 0.3‰) vs. SMOC (Standard Mean Ocean Chloride, defined as 0‰). Samples from the Western Pacific (ODP Hole 801C) have ?37Cl values ranging from -0.4 to +0.8‰. ODP Site 735 samples a 11 Ma lower section of slow spreading (0.6-1.0 cm/yr) oceanic crust. In contrast, ODP Site 801 is located in ~170 Ma fast-spreading crust (16 cm/yr). Despite those differences in age and tectonic setting, the ?37Cl values of AOC are remarkably similar, implying similar sources and mechanisms of hydration. The only previously reported AOC ?37Cl values are from the Costa Rica Rift (ODP Hole 504B). Site 504 was drilled into 5.9 Ma crust from an intermediate spreading center (~3 cm/yr). ?37Cl values range from -1.6 to -0.9‰ (Bonifacie et al., 2007). Our study expands the range of ?37Cl values reported for AOC, and can be used to reevaluate mass balance calculations improving our understanding of subduction recycling. Experimental and theoretical constraints on chlorine isotope fractionation in inorganic systems are limited to only a handful of studies. Theoretical calculations estimate that at 25°C substances in which Cl bonds with 2+ cations will be ~ +2-3‰ heavier than those in which Cl bonds with 1+ cations (Schauble et al., 2003). These calculations have led to the hypothesis that silicates should have higher 37Cl/35Cl ratios than co-existing brines at room temperature (Schauble et al., 2003). Preliminary Cl isotope fractionation experiments between pargasitic amphibole and either seawater or brine (25 wt% NaCl solution) were run in cold-seal pressure vessels at 600°C and 500 bars. Preliminary results suggest that ?37Clpargasite-Cl(aq) is within analytical error of the theoretically predicted fractionation factor, as well as measured ?37Cl values of AOC samples. Further work is planned to investigate the role of fluid-rock ratio and amphibole composition. Additional experimental data may allow us to infer the fluid-rock ratio and temperature during hydration of natural samples and to unravel the fluid histories recorded in the alteration minerals.

  4. Nonlinear numerical modelling and experimental validation of multilayer piezoelectric vibration energy scavengers

    NASA Astrophysics Data System (ADS)

    Blaževi?, D.; Zelenika, S.

    2015-05-01

    Scavenging of low-level ambient vibrations i.e. the conversion of kinetic into electric energy, is proven as effective means of powering low consumption electronic devices such as wireless sensor nodes. Cantilever based scavengers are characterised by several advantages and thus thoroughly investigated; analytical models based on a distributed parameter approach, Euler-Bernoulli beam theory and eigenvalue analysis have thus been developed and experimentally verified. Finite element models (FEM) have also been proposed employing different modelling approaches and commercial software packages with coupled analysis capabilities. An approach of using a FEM analysis of a piezoelectric cantilever bimorph under harmonic excitation is used in this work. Modal, harmonic and linear and nonlinear transient analyses are performed. Different complex dynamic effects are observed and compared to the results obtained by using a distributed parameter model. The influence of two types of finite elements and three mesh densities is also investigated. A complex bimorph cantilever, based on commercially available Midé Technology® Volture energy scavengers, is then considered. These scavengers are characterised by an intricate multilayer structure not investigated so far in literature. An experimental set-up is developed to evaluate the behaviour of the considered class of devices. The results of the modal and the harmonic FEM analyses of the behaviour of the multilayer scavengers are verified experimentally for three different tip masses and 12 different electrical load values. A satisfying agreement between numerical and experimental results is achieved.

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

    NASA Technical Reports Server (NTRS)

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

    1976-01-01

    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.

  6. Simulated and associated experimental results of CdZnTe radiation detector response for gamma-ray imaging applications

    SciTech Connect

    Verger, L.; Bonnefoy, J.P.; Gliere, A.; Ouvrier-Buffet, P.; Rosaz, M.

    1998-12-31

    Simulated and associated experimental results of a high efficiency CdZnTe (CZT) radiation detector response for gamma-ray imaging applications are presented. The model of a high efficiency semiconductor gamma ray detector takes into account several different physical phenomena involved in the detection and correction processes, namely the geometry of the irradiation, the gamma-ray`s interaction with the crystal, the physics of the semiconductor`s charge collection, the electric field distribution and the pulse height correction method. A few important decoupling assumptions allow the authors to use a one dimensional charge collection simulation with a two-dimensional field model and a full three dimensional Monte-Carlo calculation of the gamma ray interactions. The model allows calculation of charge collection and gamma ray spectra for non uniform electric field distribution in either planar, striped or pixellated detector. The model takes also into account the new CZT fast pulse correction method and its associated noise by considering the pulse height and the rise time of electron signals (Bi-Parametric spectrum) for all gamma ray interactions. Specific simulated and experimental spectra at 122 keV are presented for CZT. First, basic spectral changes are calculated for variations in crystal and detector properties like mobility, trapping lifetime and electric field profiles. Second, new experimental results of the fast pulse correction method applied to different CZT detector grades are presented. This method allows to achieve a high detection efficiency (> 80%) with a good energy resolution (< 6% FWHM) at 122 keV for a 4 x 4 x 6 mm{sup 3} CZT detector. No specific contact geometry is needed and the unusual low applied bias voltage allows to limit the aging and break voltage effects and also the dark current and its associated noise. This fast correction method is expected to be useful for medical imaging and other applications. Finally, simulated Bi-Parametric (BP) spectra expected with the fast pulse correction method according to the detector properties (electric field profiles, electron lifetime) are simulated and a qualitative comparison is provided.

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

    NASA Astrophysics Data System (ADS)

    D'Angelo, D.

    2011-03-01

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

  8. Experimental and Analytical Evaluation of a Composite Honeycomb Deployable Energy Absorber

    NASA Technical Reports Server (NTRS)

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

    2011-01-01

    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.

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

    NASA Technical Reports Server (NTRS)

    Borisov, Alexander; Dingwell, Donald B.; Oneill, Hugh ST.C.; Palme, Herbert

    1992-01-01

    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.

  10. The 110 GHz ECH installation on DII-D: Status and initial experimental results

    SciTech Connect

    Lohr, J.; Callis, R.W.; O`Neill, R.C.

    1997-05-01

    Two 110 GHz gyrotrons with nominal output power of 1 MW each have been installed on the DIII-D tokamak. The gyrotrons, produced by Gycom and Communications and Power Industries, are connected to the tokamak by windowless evacuated transmission lines using circular corrugated waveguide carrying the HE{sub 11} mode. Initial experiments with the Gycom gyrotron showed good central heating efficiency at the second harmonic resonance with record central electron temperatures for DIII-D in excess of 10 keV achieved. The beam spot in the DIII-D vacuum vessel was well focused, with a diameter of approximately 8 cm, and it could be steered poloidally by a remotely adjustable mirror. The injection was at 19 deg off-perpendicular for current drive and the beams could be modulated for studies of energy transport and power deposition. The system will be described and the initial physics results will be presented. A third gyrotron, also at 110 GHz, will be installed later this year. Progress with this CPI tube will be discussed and future plans for the ECH installation and physics experiments using it will be presented.

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

    NASA Astrophysics Data System (ADS)

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

    2013-07-01

    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.

  12. Multiple Measures of Juvenile Drug Court Effectiveness: Results of a Quasi-Experimental Design

    ERIC Educational Resources Information Center

    Rodriguez, Nancy; Webb, Vincent J.

    2004-01-01

    Prior studies of juvenile drug courts have been constrained by small samples, inadequate comparison groups, or limited outcome measures. The authors report on a 3-year evaluation that examines the impact of juvenile drug court participation on recidivism and drug use. A quasi-experimental design is used to compare juveniles assigned to drug court…

  13. Experimental High Energy Physics Research: Direct Detection of Dark Matter

    SciTech Connect

    Witherell, Michael S.

    2014-10-02

    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.

  14. Experimental limit on the cosmic diffuse ultrahigh energy neutrino flux.

    PubMed

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

    2004-07-23

    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

  15. Experimental evaluation of exhaust mixers for an Energy Efficient Engine

    NASA Technical Reports Server (NTRS)

    Kozlowski, H.; Kraft, G.

    1980-01-01

    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.

  16. Experimental results of the 140 GHz, 1 MW long-pulse gyrotron for W7-X

    NASA Astrophysics Data System (ADS)

    Koppenburg, K.; Arnold, A.; Borie, E.; Dammertz, G.; Giguet, E.; Heidinger, R.; Illy, S.; Kuntze, M.; Le Cloarec, G.; Legrand, F.; Leonhardt, W.; Lievin, C.; Neffe, G.; Piosczyk, B.; Schmid, M.; Thumm, M.

    2003-02-01

    Gyrotrons at high frequency with high output power are mainly developed for microwave heating and current drive in plasmas for thermonuclear fusion. For the stellarator Wendelstein 7-X now under construction at IPP Greifswald, Germany, a 10 MW ECRH system is foreseen. A 1 MW, 140 GHz long-pulse gyrotron has been designed and a pre-prototype (Maquette) has been constructed and tested in an European collaboration between FZK Karlsruhe, CRPP Lausanne, IPF Suttgart, IPP Greifswald, CEA Cadarache and TED Vélizy [1]. The cylindrical cavity is designed for operating in the TE28,8 mode. It is a standard tapered cavity with linear input downtaper and a non-linear uptaper. The diameter of the cylindrical part is 40.96 mm. The transitions between tapers and straight section are smoothly rounded to avoid mode conversion. The TE28,8-cavity mode is transformed to a Gaussian TEM0,0 output mode by a mode converter consisting of a rippled-wall waveguide launcher followed by a three mirror system. The output window uses a single, edge cooled CVD-diamond disk with an outer diameter of 106 mm, a window aperture of 88 mm and a thickness of 1.8 mm corresponding to four half wavelengths. The collector is at ground potential, and a depression voltage for energy recovery can be applied to the cavity and to the first two mirrors. Additional normal-conducting coils are employed to the collector in order to produce an axial magnetic field for sweeping the electron beam with a frequency of 7 Hz. A temperature limited magnetron injection gun without intermediate anode ( diode type ) is used. In short pulse operation at the design current of 40 A an output power of 1 MW could be achieved for an accelerating voltage of 82 kV without depression voltage and with a depression voltage of 25 kV an output power of 1.15 MW at an accelerating voltage of 84 kV has been measured. For these values an efficiency of 49% was obtained. At constant accelerating voltages, the output power did not change up to depression voltages of 33 kV. The output beam of the gyrotron is injected into an RF-tight microwave chamber which is equipped with two water-cooled mirrors directing the beam towards the 1 MW water load. The second mirror inside the microwave chamber contains a directional output coupler formed by a row of holes in the mirror surface. A diode detector is connected to the directional coupler and the forward power can be determined once the signal has been calibrated. This was performed by calorimetric measurement of the RF wave in short-pulse measurements. The mode purity of the Gaussian beam was measured by an IR camera and a thin dielectric target plate placed at different positions across the RF beam. The measured beam distribution agrees very well with the theoretical predictions. After some problems with the RF load, long-pulse operation was performed: The power measurements were done by the signal of the diode detector placed at the second mirror. The measured output power of the calorimetric RF-load normally shows values reduced by about 20%. Output powers of 1 MW could be achieved for 10 s, and an energy as high as 90 MJ per pulse has been produced with an output power of 0.64 MW. The pulse lengths were mainly determined by the preset values, and due to lack of experimental time no attempt was made to increase the pulse length. Only for a 100 s pulse with 0.74 MW output power, a limitation was found due to a pressure increase beyond about 10-7mbar. The gyrotron was sent back to the manufacturer Thales Electron Devices for a visual inspection, and an improved prototype was built and delivered to Forschungszentrum Karlsruhe in the middle of April 2002.

  17. Experimental analysis of a new retarding field energy analyzer

    NASA Astrophysics Data System (ADS)

    Wei, Yu-Xiang; Liu, Shu-Qing; Li, Xian-Xia; Shen, Hong-Li; Huang, Ming-Guang; Liu, Pu-Kun

    2015-06-01

    In this paper, a new compact retarding field energy analyzer (RFEA) is designed for diagnosing electron beams of a K-band space travelling-wave tube (TWT). This analyzer has an aperture plate to sample electron beams and a cylindrical electrode to overcome the defocusing effects. The front end of the analyzer constructed as a multistage depression collector (MDC) structure is intended to shape the field to prevent electrons from being accelerated to escape. The direct-current (DC) beams of the K-band space TWTs with the removing MDC can be investigated on the beam measurement system. The current density distribution of DC beams is determined by the analyzer, while the anode voltage and helix voltage of the TWTs are 7000 V and 6850 V, respectively. The current curve's slope effect due to the reflection of secondary electrons on the copper collector of the analyzer is discussed. The experimental analysis shows this RFEA has a good energy resolution to satisfy the requirement of beam measurement.

  18. Electromagnetic energy conversion at dipolarization fronts: Multispacecraft results

    NASA Astrophysics Data System (ADS)

    Huang, S. Y.; Fu, H. S.; Yuan, Z. G.; Zhou, M.; Fu, S.; Deng, X. H.; Sun, W. J.; Pang, Y.; Wang, D. D.; Li, H. M.; Li, H. M.; Yu, X. D.

    2015-06-01

    Dipolarization fronts (DFs) are believed to play important roles in transferring plasmas, magnetic fluxes, and energies in the magnetotail. Using the Cluster observations in 2003, electromagnetic energy conversion at the DFs is investigated by case and statistical studies. The case study indicates strongest energy conversion at the DF. The statistical study shows the similar features that the energy of the fields can be significantly transferred to the plasmas (load, J · E > 0) at the DFs. These results are consistent with some recent simulations. Examining the electromagnetic fluctuations at the DFs, we suggest that the wave activities around the lower hybrid frequency may play an important role in the energy dissipation.

  19. Experimental analysis of energy harvesting from self-induced flutter of a composite beam

    NASA Astrophysics Data System (ADS)

    Zakaria, Mohamed Y.; Al-Haik, Mohammad Y.; Hajj, Muhammad R.

    2015-07-01

    Previous attempts to harvest energy from aeroelastic vibrations have been based on attaching a beam to a moving wing or structure. Here, we exploit self-excited oscillations of a fluttering composite beam to harvest energy using piezoelectric transduction. Details of the beam properties and experimental setup are presented. The effects of preset angle of attack, wind speed, and load resistance on the levels of harvested power are determined. The results point to a complex relation between the aerodynamic loading and its impact on the static deflection and amplitudes of the limit cycle oscillations on one hand and the load resistance and level of power harvested on the other hand.

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

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

    Recently, Al/CdTe/Pt detectors have been proposed for the development of high resolution X-ray spectrometers. Due to the low leakage currents, these detectors allow high electric fields and the pixellization of anodes with the possibility to realize single charge carrier sensing detectors. In this work, we report on the results of electrical and spectroscopic investigations on CdTe diode detectors with Al/CdTe/Pt electrode configuration (4.1×4.1×0.75 and 4.1×4.1×2 mm3). The detectors are characterized by very low leakage currents in the reverse bias operation: 0.3 nA at 25 °C and 2.4 pA at -25 °C under a bias voltage of -1000 V. The spectroscopic performance of the detectors at both low and high photon counting rates were also investigated with a focus on the minimization of time instability, generally termed as polarization, looking for the optimum bias voltage and temperature. Good time stability, during a long-term operation of 10 h, was observed for both detectors at -25 °C and by using an electric field of 5000 V/cm. The 2 mm thick detector exhibited good energy resolution of 6.1%, 2.5% and 2.0% (FWHM) at 22.1 keV, 59.5 and 122.1 keV, respectively. Performance enhancements were obtained by using digital pulse processing techniques, especially at high photon counting rates (300 kcps). The 2 mm thick detector, after a digital pulse shape correction (PSC), is characterized by similar performance to the thin detector ones, opening up to the use of thick CdTe detectors without excessive performance degradations. This work was carried out in the framework of the development of portable X-ray spectrometers for both laboratory research and medical applications.

  1. Calibration and experimental results of a two-dimensional interferometric radiometer laboratory prototype

    NASA Astrophysics Data System (ADS)

    Camps, A.; Torres, F.; Corbella, I.; Bará, J.; Soler, X.

    1997-09-01

    In recent years, Earth observation by means of aperture synthesis radiometry has received special attention by some space agencies as a possible solution to achieve high radiometric accuracy and spatial resolution at low microwave frequencies (L band), where the apparent brightness temperature is much more sensitive to soil moisture and sea surface salinity. This paper presents the characterization and calibration procedure, as well as some synthetic images measured with an X band experimental Y-shaped Synthetic Aperture Interferometric Radiometer prototype developed at the Polytechnic University of Catalonia. The instrument is composed of a single pair of antennas that can be moved along the arms of an Y structure to synthesize a set of baselines. An experimental procedure is proposed to evaluate and then calibrate offset, inphase, quadrature, and amplitude errors generated by receivers and correlators.

  2. Performance of VAV Fan Powered Terminal Units: Experimental Results and Models for Parallel Units 

    E-print Network

    Furr, J.; O'Neal, D.; Davis, M.; Bryant, J.; Cramlet, A.

    2008-01-01

    Empirical models of airflow output, power consumption, and primary airflow were developed for parallel fan powered variable air volume terminal units at typical operating pres- sures. Both 8 in. (203 mm) and 12 in. (304 mm) primary air inlet terminal units... from three manufacturers were evaluated. Generalized models were developed from the experimental data with coefficients varying by size and manufacturer. Fan power and airflow data were collected at down- stream static pressures over a range from 0...

  3. Performance of VAV Fan Powered Terminal Units: Experimental Results and Models for Series Units 

    E-print Network

    Furr, J.; O'Neal, D.; Davis, M.; Bryant, J.; Cramlet, A.

    2008-01-01

    Empirical models of airflow output and power consump- tion were developed for series fan powered variable air volume terminal units at typical operating pressures. Terminal units with 8 in. (203 mm) and 12 in. (304 mm) primary air inlets from three different... manufacturers were evaluated. Generalized models were developed from the experimental data with coef- ficients varying by size and manufacturer. Fan power and airflow data were collected at downstream static pressures of 0.25 w.g. (63 Pa). Upstream static...

  4. Preliminary experimental results of gas recycling subsystems except carbon dioxide concentration

    NASA Astrophysics Data System (ADS)

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

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

  5. Experimental results of water film formation on various fuel forms from a fire suppression system

    SciTech Connect

    Ross, R.H.; Davis, J.R.

    1993-12-31

    The purpose of the study was to determine the thickness and coverage of water film formations on various materials during fire sprinkler deluge. An exhaustive literature search revealed that no applicable research data exists that governs water film formations from fire protection systems. Therefore, a controlled, infield, mockup was created to predict the thickness and coverage of water film on fissile material forms. This paper discusses the background, experimental procedure and the characterization of these water films.

  6. High-Temperature Oxygen Isotope Exchange Between Meteorite Sample and Water Vapor: Preliminary Experimental Results

    NASA Astrophysics Data System (ADS)

    Yu, Y.; Hewins, R. H.; Clayton, R. N.; Mayeda, T. K.

    1993-07-01

    Chondrules in carbonaceous and ordinary chondrites show slope-1 mixing lines on the oxygen three-isotope diagram, suggestive of a gas-melt exchange process during chondrule formation. In order to test this conjecture and to extend our existing knowledge of chondrule thermal history and the kinetics of reaction of interstellar dust with solar nebula gas, an experiment involving high- temperature oxygen isotope exchange between a 16O-rich sample (meteorite) and water vapor (terrestrial) has been designed. The experiment was conducted with a DELTECH vertical tube furnace with ceramic parts shielded with metal foil. The starting meteorite powder (one of two C3 carbonaceous chondrites--bulk Allende and Ornans) was pressed into a pellet and suspended at the hot spot inside the furnace. The furnace gas was a mixture of H2O vapor and H2 (1 atm total pressure, fO2 = IW-0.5) [1]. The preliminary experiments were performed at 1400 degrees C for durations from 5 minutes to 36 hours, and were terminated by quenching the samples into liquid nitrogen. The meteorite charges and the water samples collected were later analyzed for their oxygen isotope compositions. The experimental results (Fig.1) show that the exchange process has greatly modified delta-18O and delta-17O for both meteorites, which move towards the projected equilibrium point as the heating time increases. For Allende samples, the exchange proceeds quickly in the first 5 minutes, which accounts for most of the isotope exchange (~84% of total change in delta-18O(sub)A-W, and ~57% of total change in delta-17O). Then the exchange is dramatically slowed down, and takes at least 12 hours to finally reach equilibrium with the ambient water vapor. The approach to equilibrium is not a straight line on the three-isotope graph, possibly due to the presence of residual 16O-rich solids in the molten sample. A similar exchange profile is observed for Ornans samples. However, it takes longer for the Ornans sample to reach equilibrium after the initial fast exchange. The 15-hour run for Ornans is still away from the TF line, and it is moving toward the TF line about 1 permil lighter than the expected equilibrium value. Microscopic and electron microprobe studies on the heated Allende and Ornans samples (parallel runs) show that the quenched charges are composed of olivine relics and glass. The initial fast exchange observed is probably due to the rapid exchange between the ambient gas and the molten part of the meteorite sample, and the existence of olivine crystals eventually slows down the exchange process because of its much lower rate of oxygen diffusion [2]. The concentration of exchangeable gas molecules in our experiments is much greater than that in the solar nebula. The next step of this study will be experiments at higher temperatures, under conditions more similar to the chondrule-forming environment, such as flash heating and with gas diluted with Ar to obtain fewer oxygen molecules. Acknowledgments: We thank T. Grove for technical guidance, E. Jarosewich (NMNH, Washington) and B. Zanda (MNHN, Paris) for meteorite samples, and NASA (OSS) and NSF for financial support. References: [1] Baker M. B. and Grove T. L. (1985) Am. Mineral., 70, 279-287. [2] Jaoul O. et al. (1983) JGR, 88, 613-624.

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

    SciTech Connect

    Ortega, John; Turnipseed, A.; Guenther, Alex B.; Karl, Thomas G.; Day, D. A.; Gochis, David; Huffman, J. A.; Prenni, Anthony J.; Levin, E. J.; Kreidenweis, Sonia M.; DeMott, Paul J.; Tobo, Y.; Patton, E. G.; Hodzic, Alma; Cui, Y. Y.; Harley, P.; Hornbrook, R. S.; Apel, E. C.; Monson, Russell K.; Eller, A. S.; Greenberg, J. P.; Barth, Mary; Campuzano-Jost, Pedro; Palm, B. B.; Jiminez, J. L.; Aiken, A. C.; Dubey, Manvendra K.; Geron, Chris; Offenberg, J.; Ryan, M. G.; Fornwalt, Paula J.; Pryor, S. C.; Keutsch, Frank N.; DiGangi, J. P.; Chan, A. W.; Goldstein, Allen H.; Wolfe, G. M.; Kim, S.; Kaser, L.; Schnitzhofer, R.; Hansel, A.; Cantrell, Chris; Mauldin, R. L.; Smith, James N.

    2014-01-01

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

  8. Molten salt oxidation of chloro-organic compounds: Experimental results for product gas compositions and final forms studies

    SciTech Connect

    Rudolph, J.C.; Haas, P.A.; Bell, J.T.; Crosley, S.M.; Calhoun, C.L. Jr.; Gorin, A.H.; Nulf, L.E.

    1995-04-01

    Molten salt oxidation (MSO) has been selected as a promising technology for treatment of some US Department of Energy (DOE) mixed wastes. Mixed wastes are defined as those wastes that contain both radioactive components, which are regulated by the Atomic Energy Act of 1954, and hazardous waste components, which are regulated under the Resource Conservation and Recovery Act (RCRA). Oak Ridge National Laboratory (ORNL) has installed and operated a bench-scale MSO apparatus to obtain experimental information needed before the design and construction of an MSO pilot plant. The primary objective of the experiments performed was to show that dioxin and furan emissions from a molten salt oxidation (MSO) unit were below the proposed regulatory limit of 0.1 ng/m{sup 3} as 2,3,7,8-tetrachlorodibenzo-para-dioxin equivalents or toxic equivalence quotient. The feed stream was to contain 2,4-dichlorophenol, a suspected precursor to the formation of dioxin and furans. The tests were to be done over a range of salt compositions and flow rates expected in a pilot- or full-scale MSO unit. Two other objectives were to demonstrate destruction and removal efficiencies (DREs) greater than US Environmental Protection Agency requirements and to show that levels of products of incomplete combustion (PICs) are the same as, or lower than, those observed in incinerators for two common waste constituents [carbon tetrachloride (CCl{sub 4}) and CH{sub 3}CCl{sub 3}]. A final objective was to perform some initial studies of final waste forms using sulfur polymer cement (SPC). This report presents the results from the operation of the bench-scale MSO system.

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

    SciTech Connect

    Calzada, M.D.; Gamero, A.; Sola, A.

    1995-12-31

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

  10. New results in nucleon-nucleon scattering at intermediate energies

    SciTech Connect

    Spinka, H.

    1995-01-01

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

  11. Compressed air system upgrade results in substantial energy savings

    SciTech Connect

    None, None

    2002-01-01

    This case study highlights a compressed air system upgrade at BWX Technologies manufacturing plant in Lynchburg, Virginia, which replaced antiquated compressors and dryers and implemented an improved control strategy, resulting in improved energy efficiency and savings in energy and maintenance costs.

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

    E-print Network

    Hugo Pereira Da Costa

    2009-09-30

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

  13. Plucked piezoelectric bimorphs for knee-joint energy harvesting: modelling and experimental validation

    NASA Astrophysics Data System (ADS)

    Pozzi, Michele; Zhu, Meiling

    2011-05-01

    The modern drive towards mobility and wireless devices is motivating intensive research in energy harvesting technologies. To reduce the battery burden on people, we propose the adoption of a frequency up-conversion strategy for a new piezoelectric wearable energy harvester. Frequency up-conversion increases efficiency because the piezoelectric devices are permitted to vibrate at resonance even if the input excitation occurs at much lower frequency. Mechanical plucking-based frequency up-conversion is obtained by deflecting the piezoelectric bimorph via a plectrum, then rapidly releasing it so that it can vibrate unhindered; during the following oscillatory cycles, part of the mechanical energy is converted into electrical energy. In order to guide the design of such a harvester, we have modelled with finite element methods the response and power generation of a piezoelectric bimorph while it is plucked. The model permits the analysis of the effects of the speed of deflection as well as the prediction of the energy produced and its dependence on the electrical load. An experimental rig has been set up to observe the response of the bimorph in the harvester. A PZT-5H bimorph was used for the experiments. Measurements of tip velocity, voltage output and energy dissipated across a resistor are reported. Comparisons of the experimental results with the model predictions are very successful and prove the validity of the model.

  14. Nitrogen ion implantation in metals - A comparison of Experimental Results and Computer Simulations

    NASA Astrophysics Data System (ADS)

    Sanghera, Harpreet; Sullivan, John

    2000-04-01

    The aim of this work is to investigate the effects of ion energy, current density and dose on low energy nitrogen ion implantation profiles in metal surfaces. For this purpose, metal (Al, Fe, Cu and Au) bulk samples, with a purity of 99.9energies of 2, 3, 4 and 5 keV with current densities of 1 mA/cm2 and 5 mA/cm2 for each ion energy. The ion fluences for these experiments range from 6xE16 and 3xE17 ions/cm2. The chemical composition and chemical structure of the implanted metals were investigated by XPS and Angle Resolved X-ray Photoelectron Spectroscopy (ARXPS). The concentration profiles of nitrogen ions implanted into metals were measured by X-ray Photoelectron Spectroscopy (XPS) and these were compared with the profiles created using computer simulation codes SUSPRE and SATVAL.

  15. An experimental-finite element analysis on the kinetic energy absorption capacity of polyvinyl alcohol sponge.

    PubMed

    Karimi, Alireza; Navidbakhsh, Mahdi; Razaghi, Reza

    2014-06-01

    Polyvinyl alcohol (PVA) sponge is in widespread use for biomedical and tissue engineering applications owing to its biocompatibility, availability, relative cheapness, and excellent mechanical properties. This study reports a novel concept of design in energy absorbing materials which consist in the use of PVA sponge as an alternative reinforcement material to enhance the energy loss of impact loads. An experimental study is carried out to measure the mechanical properties of the PVA sponge under uniaxial loading. The kinetic energy absorption capacity of the PVA sponge is computed by a hexahedral finite element (FE) model of the steel ball and bullet through the LS-DYNA code under impact load at three different thicknesses (5, 10, 15mm). The results show that a higher sponge thickness invokes a higher energy loss of the steel ball and bullet. The highest energy loss of the steel ball and bullet is observed for the thickest sponge with 160 and 35J, respectively. The most common type of traumatic brain injury in which the head subject to impact load causes the brain to move within the skull and consequently brain hemorrhaging. These results suggest the application of the PVA sponge as a great kinetic energy absorber material compared to commonly used expanded polystyrene foams (EPS) to absorb most of the impact energy and reduces the transmitted load. The results might have implications not only for understanding of the mechanical properties of PVA sponge but also for use as an alternative reinforcement material in helmet and packaging material design. PMID:24863223

  16. Mixing Silicate Melts with High Viscosity Contrast by Chaotic Dynamics: Results from a New Experimental Device

    NASA Astrophysics Data System (ADS)

    de Campos, Cristina; Perugini, Diego; Ertel-Ingrisch, Werner; Dingwell, Donald B.; Poli, Giampiero

    2010-05-01

    A new experimental device has been developed to perform chaotic mixing between high viscosity melts under controlled fluid-dynamic conditions. The apparatus is based on the Journal Bearing System (JBS). It consists of an outer cylinder hosting the melts of interest and an inner cylinder, which is eccentrically located. Both cylinders can be independently moved to generate chaotic streamlines in the mixing system. Two experiments were performed using as end-members different proportions of a peralkaline haplogranite and a mafic melt, corresponding to the 1 atm eutectic composition in the An-Di binary system. The two melts were stirred together in the JBS for ca. two hours, at 1,400° C and under laminar fluid dynamic condition (Re of the order of 10-7). The viscosity ratio between the two melts, at the beginning of the experiment, was of the order of 103. Optical analyses of experimental samples revealed, at short length scale (of the order of ?m), a complex pattern of mixed structures. These consisted of an intimate distribution of filaments; a complex inter-fingering of the two melts. Such features are typically observed in rocks thought to be produced by magma mixing processes. Stretching and folding dynamics between the melts induced chaotic flow fields and generated wide compositional interfaces. In this way, chemical diffusion processes become more efficient, producing melts with highly heterogeneous compositions. A remarkable modulation of compositional fields has been obtained by performing short time-scale experiments and using melts with a high viscosity ratio. This indicates that chaotic mixing of magmas can be a very efficient process in modulating compositional variability in igneous systems, especially under high viscosity ratios and laminar fluid-dynamic regimes. Our experimental device may replicate magma mixing features, observed in natural rocks, and therefore open new frontiers in the study of this important petrologic and volcanological process.

  17. Comparison of dynamic analysis of a Schilling hydraulic manipulator with experimental results

    SciTech Connect

    Baker, C.P.; Lew, J.Y.; Evans, M.S.; Magee, D.P.

    1993-07-01

    Two independent models of the dynamics of a Schilling Titan II hydraulic manipulator were developed and compared in order to obtain an accurate model of the manipulator dynamics. These models will be used in the development of feedback control laws and active damping algorithms. One of the model is an analytical model which was developed {open_quotes}by hand{close_quotes} with the assistance of computer symbolic manipulation. The other is a numerical model developed using a commercially available dynamics code. The data from these models were then compared with experimental data from an actual Titan II manipulator.

  18. Experimental results of water film formation on various fuel forms from a fire suppression system

    SciTech Connect

    Ross, R.H.; Davis, J.R.

    1994-12-31

    The purpose of the study was to determine the thickness and coverage of water film formations on various materials during fire sprinkler deluge. The primary criticality safety concern with automatic fire suppression systems is the increased amount of water that a film adds to the interstitial volume of an array per unit time. An exhaustive literature search revealed that no applicable research data exist that govern water film formations from fire protection systems. Therefore, a controlled, infield, mockup was created to predict the thickness and coverage of water film on fissile material forms. This paper discusses the background, experimental procedure, and the characterization of these water films.

  19. Preliminary experimental results of gas recycling subsystems except carbon dioxide concentration

    NASA Technical Reports Server (NTRS)

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

    1987-01-01

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

  20. Line tension approaching a first-order wetting transition: Experimental results from contact angle measurements

    NASA Astrophysics Data System (ADS)

    Wang, J. Y.; Betelu, S.; Law, B. M.

    2001-03-01

    The line tension values of n-octane and 1-octene on a hexadecyltrichlorosilane coated silicon wafer, are determined by contact angle measurements at temperatures near a first-order wetting transition Tw. It is shown experimentally that the line tension changes sign as the temperature increases toward Tw in agreement with a number of theoretical predictions. A simple phenomenological model possessing a repulsive barrier at l0=5.1+/-0.2 nm and a scale factor of B=78+/-6 provides a quantitative description of the experiments.

  1. Experimental and numerical results on a shear layer excited by a sound pulse

    NASA Technical Reports Server (NTRS)

    Maestrello, L.; Bayliss, A.; Turkel, E.

    1979-01-01

    The behavior of a sound in a jet was investigated. It is verified that the far-field acoustic power increased with flow velocity for the lower and medium frequency range. Experimentally, an attenuation at higher frequencies is also observed. This increase is found numerically to be due primarily to the interactions between the mean vorticity and the fluctuation velocities. Spectral decomposition of the real time data indicates that the power increase occurs in the low and middle frequency range, where the local instability waves have the largest spatial growth rate. The connection between this amplification and the local instability waves is discussed.

  2. Transmission and phase balancing of alternating phase-shifting masks (5x): theoretical and experimental results

    NASA Astrophysics Data System (ADS)

    Griesinger, Uwe A.; Pforr, Rainer; Knobloch, Juergen; Friedrich, Christoph M.

    1999-12-01

    Dual trench alternating phase shifting masks with an optimized value of the so-called shallow trench depth represents an interesting approach to overcome aerial image imbalances. In order to get a better understanding of the possibilities and limits of this approach, especially for 5X reduction, theoretical and experimental investigations were accomplished. In this paper experimental data obtained from 5X dual trench type alternating PSMs, using DUV-lithography are introduced and compared with 3D-mask simulations. The masks were fabricated with different etch depths and contain parts of typical DRAM patterns. Besides the transmission balancing also the phase balancing has an important influence on the effective process window of an alternating PSM. The effective phase error can be measured with an AIMS-system (MSM100). The comparison with simulated data allows the determination of the phase error. In a second step the influence of different balancing methods on phase and transmission were investigated with the TEMPEST mask simulator for unpolarized light. The optimization of the balancing with respect to the CD-bias, undercut and etch depth will be shown and a first approach of a sensitivity analysis will be presented.

  3. From the experimental simulation to integrated non-destructive analysis by means of optical and infrared techniques: results compared

    NASA Astrophysics Data System (ADS)

    Sfarra, S.; Ibarra-Castanedo, C.; Lambiase, F.; Paoletti, D.; Di Ilio, A.; Maldague, X.

    2012-11-01

    In this work the possibility of modeling manufacturing ceramic products is analyzed through the application of transient thermography, holographic interferometry and digital speckle photography, in order to identify the subsurface defects characteristics. This integrated method could be used to understand the nature of heterogeneous materials (such as plastic, sponge simulating a void, wood, aluminum) potentially contained within ceramic materials, as well as to predict crack formation due to them. The paper presents the analysis of green ceramic tile containing defects of different types and sizes located at different depths. The finite element method is used for solving the problem of transient heat transfer occurring in experimental conditions. Unknown parameters of the numerical model (such as convective heat transfer coefficients and sample surface emissivity) were adjusted to obtain numerical simulation results as close as possible to those obtained experimentally. Similarities and differences between experimental and simulated data are analyzed and discussed. Possibilities for improving the results and further developments are proposed.

  4. Subsonic Kernel-Function Flutter Analysis of a Highly Tapered Tail Surface and Comparison with Experimental Results

    NASA Technical Reports Server (NTRS)

    Walberg, Gerald D.

    1960-01-01

    A flutter analysis employing the kernel function for three-dimensional, subsonic, compressible flow is applied to a flutter-tested tail surface which has an aspect ratio of 3.5, a taper ratio of 0.15, and a leading-edge sweep of 30 deg. Theoretical and experimental results are compared at Mach numbers from 0.75 to 0.98. Good agreement between theoretical and experimental flutter dynamic pressures and frequencies is achieved at Mach numbers to 0.92. At Mach numbers from 0.92 to 0.98, however, a second solution to the flutter determinant results in a spurious theoretical flutter boundary which is at a much lower dynamic pressure and at a much higher frequency than the experimental boundary.

  5. Recent experimental and analytical results of BNL direct containment heating programs

    SciTech Connect

    Ginsberg, T.; Tutu, N.K.

    1986-01-01

    The direct containment heating (DCH) scenario involves high-pressure ejection of molten core material from the reactor vessel into the region beneath the vessel and into various subcompartments of the containment building. The stored energy in the melt consists of the sensible energy of melt and the chemical reaction energy of the various components assuming that they can react with either the oxygen or the steam within containment. The metallic phase may first react with steam, if local conditions permit, and thereby produce hydrogen. The hydrogen may then burn at some later time at a different location. In order to predict the containment response, one must follow the melt through the various subcompartments of the containment building, while computing the integrated release of energy from the melt to the containment atmosphere and the quantity of hydrogen produced during the time period that the melt is suspended. The BNL research program in the area of direct containment heating is directed towards the development of a methodology to predict the hydrodynamic, chemical and thermal interactions which could take place in three regions of PWR containment buildings: the reactor cavity, the intermediate compartments (e.g., steam generator room) and the containment dome. Separate effects, scaled experiments are performed related to selected aspects of the DCH problem, and analytical models are developed to characterize the relevant phenomena.

  6. American Institute of Aeronautics and Astronautics Experimental Results of Structural Health Monitoring of

    E-print Network

    an opportunity to exercise a number of structural health monitoring (SHM) techniques and nondestructive testing = Nondestructive Testing NREL = National Renewable Energy Laboratory NWTC = National Wind Technology Center PAC, developed under a Sandia National Laboratories R&D program, was recently fatigue tested to blade failure

  7. Irradiation-induced magnetic ordering in SiC: Experimental results and a density functional study

    SciTech Connect

    He, Xiujie; Zhang, Baoliang; Key Laboratory of Nuclear Radiation and Nuclear Energy Technology, Chinese Academy of Sciences, Shanghai 201800 ; Tan, Jie; Zhao, Mingwen; Liu, Xiangdong; Xia, Huihao; He, Zhoutong; Yang, Xinmei; Zhou, Xingtai

    2013-12-23

    Magnetism of 6H-SiC single crystals implanted with 3 MeV protons is studied both experimentally and theoretically. We found that proton irradiation can induce stable ferromagnetism in 6H-SiC with a Curie temperature above 300 K. There is a dose window available for tuning the magnetization of the samples. The maximum saturation magnetizations (0.17 emu/g) are three orders of magnitude larger than that reported in neutron-irradiated SiC crystals (1 × 10{sup ?4} emu/g). First-principles calculations indicate that the ferromagnetism is related to the divacancy-related defects (V{sub Si}V{sub C} + nH, (n = 1–3)) generated under proton irradiation. This offers a promising route for the development of metal-free SiC magnets.

  8. Performance of the Argonne Wakefield Accelerator facility and initial experimental results

    SciTech Connect

    Gai, W.; Conde, M.; Cox, G.; Konecny, R.; Power, J.; Schoessow, P.; Simpson, J.; Barov, N.

    1997-09-01

    The Argonne Wakefield Accelerator (AWA) facility has begun its experimental program. This unique facility is designed to address advanced acceleration research which requires very short, intense electron bunches. The facility incorporates two photo-cathode based electron sources. One produces up to 100 nC, multi-kiloamp drive bunches which are used to excite wakefields in dielectric loaded structures and in plasma. The second source produces much lower intensity witness pulses which are used to probe the fields produced by the drive. The drive and witness pulses can be precisely timed as well as laterally positioned with respect to each other. The authors discuss commissioning, initial experiments, and outline plans for a proposed 1 GeV demonstration accelerator.

  9. Performance of the Argonne Wakefield Accelerator Facility and initial experimental results

    SciTech Connect

    Gai, W.; Conde, M.; Cox, G.; Konecny, R.; Power, J.; Schoessow, P.; Simpson, J.; Barov, N.

    1996-10-01

    The Argonne Wakefield Accelerator facility has begun its experimental program. It is designed to address advanced acceleration research requiring very short, intense electron bunches. It incorporates two photocathode based electron sources. One produces up to 100 nC, multi-kiloamp `drive` bunches which are used to excite wakefields in dielectric loaded structures and in plasma. The second source produces much lower intensity `witness` pulses which are used to probe the fields produced by the drive. The drive and witness pulses can be precisely timed as well as laterally positioned with respect to each other. This paper discusses commissioning, initial experiments, and outline plans for a proposed 1 GeV demonstration accelerator.

  10. Validation data for photochemical mechanisms: experimental results. Interim report, April 1986-December 1987

    SciTech Connect

    Sexton, K.G.; Arnold, J.R.; Jeffries, H.E.; Kale, T.L.; Kamens, R.M.

    1988-11-01

    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 using NOx and various hydrocarbons and hydrocarbon mixtures. Experiments were also conducted to better understand and characterize (1) the chamber when operated dynamically to simulate continuous emissions and dilution, and (2) the solar radiation inside the smog chamber. The chamber experiments described in the report were added to the existing UNC data base for model testing, bringing the total number of dual experiments in the data base to 417. The data base is available on an ANSI-formatted magnetic tape.

  11. Experimental and computational ice shapes and resulting drag increase for a NACA 0012 airfoil

    NASA Technical Reports Server (NTRS)

    Shin, Jaiwon; Bond, Thomas H.

    1992-01-01

    Tests were conducted in the Icing Research Tunnel (IRT) at LeRC to document the repeatability of the ice shape over the range of temperatures varying from -15 to 28 F. Measurements of drag increase due to the ice accretion were also made. The ice shape and drag coefficient data, with varying total temperatures at two different airspeeds, were compared with the computational predictions. The calculations were made with the 2D LEWICE/IBL code which is a combined code of LEWICE and the interactive boundary layer method developed for iced airfoils. Comparisons show good agreement with the experimental data in ice shapes. The calculations show the ability of the code to predict drag increases as the ice shape changes from a rime shape to a glaze shape.

  12. Experimental and clinical results with proximal end-to-end duodenojejunostomy for pathologic duodenogastric reflux.

    PubMed Central

    DeMeester, T R; Fuchs, K H; Ball, C S; Albertucci, M; Smyrk, T C; Marcus, J N

    1987-01-01

    Existing Roux-en-Y bile diversion procedures for duodenogastric reflux coupled with distal gastric resection or antrectomy and vagotomy have varied success due to interruption of the physiologic relationships between stomach and duodenum, the reduction of the gastric reservoir, the side effects of vagotomy, and the effect of the Roux limb on gastric emptying. A new bile diversion procedure, suprapapillary Roux-en-Y duodenojejunostomy, was studied, which eliminates the need for gastric resection to prevent jejunal ulcers by preserving duodenal inhibition of gastric acid secretion and the protective effects of duodenal secretion on the surrounding mucosa. Experimentally, the incidence of jejunal ulceration was significantly decreased by the preservation of the proximal duodenum. Clinically, bile diversion by suprapapillary Roux-en-Y duodenojejunostomy alleviates symptoms of duodenogastric reflux disease without being ulcerogenic (in the presence of normal gastric secretion) or prolonging gastric emptying. PMID:3662657

  13. Experimental deformation of polycrystalline H2O ice at high pressure and low temperature - Preliminary results

    NASA Astrophysics Data System (ADS)

    Durham, W. B.; Heard, H. C.; Kirby, S. H.

    1983-11-01

    A preliminary study is carried out of involving 70 constant strain deformation tests on pure polycrystalline H2O ice under conditions covering most of the stability field of ice Ih. Brittle failure of Ih is found to be promoted by lower P, lower T, and higher strain rates. Ductile flow is found to be promoted by higher P, higher T, and lower strain rates. The brittle failure of ice Ih is found to be most unusual. The fracture strength is a positive function of P only below 50 MPa. At pressures greater than this, the fracture strength is independent of P, and the fracture plane lies approximately 45 deg from the load axis. It is believed that existing extrapolation based on existing experimental data to Ganymede and Callisto may be badly in error.

  14. Overview of experimental results and code validation activities at Alcator C-Mod

    NASA Astrophysics Data System (ADS)

    Greenwald, M.; Bader, A.; Baek, S.; Barnard, H.; Beck, W.; Bergerson, W.; Bespamyatnov, I.; Bitter, M.; Bonoli, P.; Brookman, M.; Brower, D.; Brunner, D.; Burke, W.; Candy, J.; Chilenski, M.; Chung, M.; Churchill, M.; Cziegler, I.; Davis, E.; Dekow, G.; Delgado-Aparicio, L.; Diallo, A.; Ding, W.; Dominguez, A.; Ellis, R.; Ennever, P.; Ernst, D.; Faust, I.; Fiore, C.; Fitzgerald, E.; Fredian, T.; Garcia, O. E.; Gao, C.; Garrett, M.; Golfinopoulos, T.; Granetz, R.; Groebner, R.; Harrison, S.; Harvey, R.; Hartwig, Z.; Hill, K.; Hillairet, J.; Howard, N.; Hubbard, A. E.; Hughes, J. W.; Hutchinson, I.; Irby, J.; James, A. N.; Kanojia, A.; Kasten, C.; Kesner, J.; Kessel, C.; Kube, R.; LaBombard, B.; Lau, C.; Lee, J.; Liao, K.; Lin, Y.; Lipschultz, B.; Ma, Y.; Marmar, E.; McGibbon, P.; Meneghini, O.; Mikkelsen, D.; Miller, D.; Mumgaard, R.; Murray, R.; Ochoukov, R.; Olynyk, G.; Pace, D.; Park, S.; Parker, R.; Podpaly, Y.; Porkolab, M.; Preynas, M.; Pusztai, I.; Reinke, M.; Rice, J.; Rowan, W.; Scott, S.; Shiraiwa, S.; Sierchio, J.; Snyder, P.; Sorbom, B.; Soukhanovskii, V.; Stillerman, J.; Sugiyama, L.; Sung, C.; Terry, D.; Terry, J.; Theiler, C.; Tsujii, N.; Vieira, R.; Walk, J.; Wallace, G.; White, A.; Whyte, D.; Wilson, J.; Wolfe, S.; Woller, K.; Wright, G.; Wright, J.; Wukitch, S.; Wurden, G.; Xu, P.; Yang, C.; Zweben, S.

    2013-10-01

    Recent research on the Alcator C-Mod tokamak has focused on a range of scientific issues with particular emphasis on ITER needs and on detailed comparisons between experimental measurements and predictive models. Research on ICRF (ion cyclotron range of frequencies) heating emphasized the origins and mitigation of metallic impurities while work on lower hybrid current drive experiments have focused on linear and nonlinear wave interactions that limit efficiency at high densities in regimes with low single pass absorption. Experiments in core turbulence and transport focused on quantitative, multi-field comparisons between nonlinear gyro-kinetics simulations and experimental measurements of profiles, fluxes and fluctuations. Experiments into self-generated rotation observed spontaneous flow reversal at a critical density identical to the transition density between linear ohmic confinement and saturated ohmic confinement regimes. H-mode studies have measured pedestal widths consistent with kinetic-ballooning-mode-like instabilities, while the pedestal heights quantitatively match the EPED code predictions. Experiments with I-mode have increased the operating window for this promising edge-localized-mode-free regime. Extrapolation of I-mode to ITER suggests that the fusion gain Q ? 10 could be possible in ITER. Investigations into the physics and scaling of the power exhaust channel width in attached enhanced D-alpha H-mode and L-mode plasma showed a direct connection between the midplane pressure-folding length and the outer divertor target footprint. The width was found to scale inversely with IP, while being independent of conducted power, BT or q95 and insensitive to the scrape-off layer connection length—a behaviour that suggests critical-gradient physics sets both pressure and heat-flux profiles.

  15. Microfabricated Air-Microfluidic Sensor for Personal Monitoring of Airborne Particulate Matter: Design, Fabrication, and Experimental Results

    EPA Science Inventory

    We present the design and fabrication of a micro electro mechanical systems (MEMS) air-microfluidic particulate matter (PM) sensor, and show experimental results obtained from exposing the sensor to concentrations of tobacco smoke and diesel exhaust, two commonly occurring P...

  16. Composite CaO-Based CO2 Sorbents Synthesized by Ultrasonic Spray Pyrolysis: Experimental Results and Modeling

    E-print Network

    Suslick, Kenneth S.

    the experimental results and provide an explanation for the effect of sintering and agglomeration sorbing capacity, fast kinetics, and high thermal/mechanical stability are required. Among high cost, high capacity, fast kinetics, and selectivity. CaO, however, suffers from performance degradation

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

    E-print Network

    Eustice, Ryan

    Experimental Results in Synchronous-Clock One-Way-Travel-Time Acoustic Navigation for Autonomous in the development and deployment of a synchronous-clock acous- tic navigation system suitable for the simultaneous navigation of multiple underwater vehicles. The goal of this work is to enable the task of navigating

  18. Extraction of the defect density of states in microcrystalline silicon from experimental results and simulation studies

    NASA Astrophysics Data System (ADS)

    Tibermacine, T.; Merazga, A.; Ledra, M.; Ouhabab, N.

    2015-09-01

    The constant photocurrent method in the ac-mode (ac-CPM) is used to determine the defect density of states (DOS) in hydrogenated microcrystalline silicon (?c-Si:H) prepared by very high frequency plasma-enhanced chemical vapor deposition (VHF-PECVD). The absorption coefficient spectrum (ac-?(hv)), is measured under ac-CPM conditions at 60 Hz. The measured ac-?(hv) is converted by the CPM spectroscopy into a DOS distribution covering a portion in the lower energy range of occupied states. We have found that the density of valence band-tail states falls exponentially towards the gap with a typical band-tail width of 63 meV. Independently, computer simulations of the ac-CPM are developed using a DOS model that is consistent with the measured ac-?(hv) in the present work and a previously measured transient photocurrent (TPC) for the same material. The DOS distribution model suggested by the measurements in the lower and in the upper part of the energy-gap, as well as by the numerical modelling in the middle part of the energy-gap, coincide reasonably well with the real DOS distribution in hydrogenated microcrystalline silicon because the computed ac-?(hv) is found to agree satisfactorily with the measured ac-?(hv).

  19. Micronozzles: 3D numerical structural and gas dynamics modeling, fabrication, and preliminary experimental results

    NASA Astrophysics Data System (ADS)

    Borovkov, Alexei I.; Pyatishev, Evgenij N.; Lurie, Mihail S.; Korshunov, Andrey V.; Akulshin, Y. D.; Dolganov, A. G.; Sabadash, V. O.

    2001-02-01

    The tiny engines, founded on the principle of reactive thrust, are one of most perspective actuators developed by modern micromechanics. These engines can be applied for such apparent problems, as orientation and stabilization of small space objects, but also as local or distributed reactive thrust of new phylum of aerospace objects, for control of boundary layer of flying objects and in series of converting power devices of different purposes. Distinctive features of jet tiny engines are profitability (very large thrust-to-weight ratio) and high (milliseconds) response, which makes them to irreplaceable elements in control systems and, specially, in distributed power generations. These features are provided the minimum sizes, high pressure in working chambers and hypersonic velocity of propulsive jet. Topologically micronozzles are designed as the flat batch devices (3 layers as minimum). The lower and upper layers make flat walls of the nozzle and mainly influence on strength properties of the device. The mean layer reshapes geometry and determines gas dynamic characteristic of the nozzle. A special problem is the opening-up of the combustion-mixture, which is not esteemed in this work. It is necessary to allow for effect of considerable local stresses arising at the expense of static and dynamic loading at design of the jet tiny engines. Thermal gas dynamic processes in the chamber and nozzle determine the values and nature of these stresses, which are hardly studied for the microdevices. The priority is mathematical and experimental simulation of these processes. The most suitable object for initial phase of experimental simulation is the 'cold' engine. The demanded chamber static pressure is formed by external compressed air. In Laboratory of Microtechnology and MicroElectroMechanical Systems a number of such tiny engines with different shapes of the chamber's and the nozzles' surfaces were designed, made and tested. The engines were produced from photosensing glass by methods of microtechnology on the basis of photolithography processes. After expositing through a mask the latent map of the glass was 'showed' by heat treatment and etched. The obtained parts sitallized and subjected to level-by-level assembly. At experiments on 'ardent' engines it is supposed to keep the basic stages of a technological route, but to use stronger and temperature- resistant materials including coating from high-strength membranes plotted by vacuum deposition methods. During trial tests, for the 'cold' engine with an altitude of a nozzle of 1.2 mm and width of the throat of 0.4 mm at chamber pressure 0.6 MPa the exhaust velocity on escaping of the nozzle about 1.5 M was obtained. The engine thrust has compounded 45 gr. The obtained data are in satisfactory conformity with 1D computation and allow to proceed piloting objects of other range of the characteristics. The microactuators having high response and profitability are demanded for perspective small aerospace objects. This activators are indispensable for creation of distributed thrust and control of boundary layer of micro air flying objects (MAV), for devices of stabilization and orientation of micro-satellites. A number of such activators forms on the areas of flat micronozzle devices. Developed micronozzles should provide demanded parameters at the expense of a high level of pressure in working chamber and supersonic exhaust velocities. At creation of the micronozzle the effect of considerable loads arising as at the expense of static, and dynamic loading should be mentioned. Thermomechanics-gasodynamic processes in the chamber and nozzle determine the nature and kind of loading. Mathematical and experimental simulation of these hardly studied for the microscopic object processes is necessary.

  20. Micronozzles: 3D numerical structural and gas dynamics modeling, fabrication, and preliminary experimental results

    NASA Astrophysics Data System (ADS)

    Borovkov, Alexei I.; Pyatishev, Evgenij N.; Lurie, Mihail S.; Korshunov, Andrey V.; Akulshin, Y. D.; Dolganov, A. G.; Sabadash, V. O.

    2000-02-01

    The tiny engines, founded on the principle of reactive thrust, are one of most perspective actuators developed by modern micromechanics. These engines can be applied for such apparent problems, as orientation and stabilization of small space objects, but also as local or distributed reactive thrust of new phylum of aerospace objects, for control of boundary layer of flying objects and in series of converting power devices of different purposes. Distinctive features of jet tiny engines are profitability (very large thrust-to-weight ratio) and high (milliseconds) response, which makes them to irreplaceable elements in control systems and, specially, in distributed power generations. These features are provided the minimum sizes, high pressure in working chambers and hypersonic velocity of propulsive jet. Topologically micronozzles are designed as the flat batch devices (3 layers as minimum). The lower and upper layers make flat walls of the nozzle and mainly influence on strength properties of the device. The mean layer reshapes geometry and determines gas dynamic characteristic of the nozzle. A special problem is the opening-up of the combustion-mixture, which is not esteemed in this work. It is necessary to allow for effect of considerable local stresses arising at the expense of static and dynamic loading at design of the jet tiny engines. Thermal gas dynamic processes in the chamber and nozzle determine the values and nature of these stresses, which are hardly studied for the microdevices. The priority is mathematical and experimental simulation of these processes. The most suitable object for initial phase of experimental simulation is the 'cold' engine. The demanded chamber static pressure is formed by external compressed air. In Laboratory of Microtechnology and MicroElectroMechanical Systems a number of such tiny engines with different shapes of the chamber's and the nozzles' surfaces were designed, made and tested. The engines were produced from photosensing glass by methods of microtechnology on the basis of photolithography processes. After expositing through a mask the latent map of the glass was 'showed' by heat treatment and etched. The obtained parts sitallized and subjected to level-by-level assembly. At experiments on 'ardent' engines it is supposed to keep the basic stages of a technological route, but to use stronger and temperature- resistant materials including coating from high-strength membranes plotted by vacuum deposition methods. During trial tests, for the 'cold' engine with an altitude of a nozzle of 1.2 mm and width of the throat of 0.4 mm at chamber pressure 0.6 MPa the exhaust velocity on escaping of the nozzle about 1.5 M was obtained. The engine thrust has compounded 45 gr. The obtained data are in satisfactory conformity with 1D computation and allow to proceed piloting objects of other range of the characteristics. The microactuators having high response and profitability are demanded for perspective small aerospace objects. This activators are indispensable for creation of distributed thrust and control of boundary layer of micro air flying objects (MAV), for devices of stabilization and orientation of micro-satellites. A number of such activators forms on the areas of flat micronozzle devices. Developed micronozzles should provide demanded parameters at the expense of a high level of pressure in working chamber and supersonic exhaust velocities. At creation of the micronozzle the effect of considerable loads arising as at the expense of static, and dynamic loading should be mentioned. Thermomechanics-gasodynamic processes in the chamber and nozzle determine the nature and kind of loading. Mathematical and experimental simulation of these hardly studied for the microscopic object processes is necessary.

  1. The results of computer and experimental studies on compressing the ultrashort photoelectron bunches with time-dependent electric fields

    NASA Astrophysics Data System (ADS)

    Andreev, Sergey A.; Bryukhnevich, Gennadiy I.; Degtyareva, Valentina P.; Greenfield, Dmitriy E.; Lozovoi, Valeriy; Monastyrskiy, Mikhail A.; Schelev, Mikhail Y.; Serdiuchenko, Yuri N.; Tarasov, Victor A.; Vorobiev, Nikolai S.

    2007-01-01

    Some theoretical milestones, in definite sense summarizing our studies on temporal compressing of photoelectron bunch with time-depending electric fields, are elucidated. The recent experimental results on dynamic compression of photoelectron bunches of picosecond duration, gained with the use of a newly designed photoelectron gun employing the electric field ramp of about 1.5 kV/ns, are presented and compared with the results of computer simulation.

  2. [Recent morphologic and experimental results on the normal and impaired function of cutaneous vascular organ].

    PubMed

    Hammersen, F

    1976-10-01

    The objective of this article is to briefly review our present knowledge of the pattern, the functional behaviour and the fine structure of the cutaneous papillary vessels and their alterations under various pathological conditions. The shape of these capillary loops varies within wide ranges dependant on the functional state of the covering epidermis. If the latter is hyperplastic the vessels are elongated, twisted and coiled. In case of epidermal atrophy the capillaries become shorter, decrease in number until their final complete absorption. At the level of the electron microscope the capillary wall clearly shows to consist of 2--3 or more endothelial cells of high electron density encircling an always narrow lumen. Both the inner and outer endothelial surfaces are irregular in outline and the cytoplasm is crowded with filaments of 50--70 A in diameter. In addition it is characterized by the occurrence of a larger number of vacuoles and Weibel-Palade bodies, the latter serving as an excellent marker for endothelial cells to e.g. clearly decide the morphogenesis of certain vascular tumors. Along their apex the capillary loops show a fenestrated endothelium particularly at their adepidermal sites. The basal lamina is multilayered and thereby giving a scroll-like appearance in cross sections. At the ultrastructural level endothelial cells are only provided with a limited repertoire of reactions to noxious stimuli. Among these are: (1) an increase in vesiculation and organelles, (2) the formation of cytoplasmic processes often accompanied by the development of interendothelial "gaps" and (3) alterations - mostly thickenings - of the basement membrane. These different fine structural changes were shown to also occur in various diseases of the skin including it's vascular tumors. In experimental research of the skin microvasculature the most spectacular technique was that of a human skin chamber as originated by Branemark. Thereby most of our older findings as to the functional behavior of the microcirculation in laboratory animals were shown to be valid and hence transferable to humans provided similar experimental approaches were used. Finally the vitalmicroscopy and ultrastructure of tumors (melanoma, hemangiopericytoma and neurilemmoma) transplanted into the hamster cheek pouch are briefly outlined. PMID:993020

  3. Experimental and theoretical high energy physics research. [UCLA

    SciTech Connect

    Buchanan, Charles D.; Cline, David B.; Byers, N.; Ferrara, S.; Peccei, R.; Hauser, Jay; Muller, Thomas; Atac, Muzaffer; Slater, William; Cousins, Robert; Arisaka, Katsushi

    1992-01-01

    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.

  4. UVA experimental and high energy physics. Final grant report

    SciTech Connect

    Cox, B.

    1999-10-07

    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.

  5. Ocean thermal energy conversion plants : experimental and analytical study of mixing and recirculation

    E-print Network

    Jirka, Gerhard H.

    Ocean thermal energy conversion (OTEC) is a method of generating power using the vertical temperature gradient of the tropical ocean as an energy source. Experimental and analytical studies have been carried out to determine ...

  6. Comparison between experimental and theoretical results for the fast-head-tail instability in PEP

    SciTech Connect

    Not Available

    1983-07-01

    The fast-head-tail instability has been observed at several storage rings. This is a single-bunch beam instability where the unstable motion can occur in either the horizontal or vertical plane. Kohaupt and Talman have offered a simplified treatment of this instability by modeling the bunch as two rigid macroparticles executing synchrotron oscillations and thus exchanging their longitudinal positions periodically. While the wake field forces which drive the fast-head-tail instability are the same ones which drive the slow-head-tail instability, the growth mechanism is considerably different. The two particle model describes the particle motion with two normal modes; below a certain stability threshold, these two modes are stable with different frequencies. In the limit of zero beam current only one of these modes has a center-of-charge motion. However, as the current is increased, both modes acquire center-of-charge motions and at threshold the center-of-charge components of their motions become equal in magnitude, thus when the center-of-charge motion is excited by an impulse as by an injection kicker, the relative amplitude of the two modes depends upon the ratio of bunch current to the threshold current. We shall describe the character of this coherent motion both theoretically and experimentally.

  7. Nonconventional control of the flexible pole-cart balancing problem: Experimental results.

    PubMed

    Dadios, E P; Williams, D J

    1998-01-01

    Emerging techniques of intelligent or learning control seem attractive for applications in manufacturing and robotics. It is however important to understand the capabilities of such control systems. In the past the inverted pendulum has been used as a test case, however, this problem is not sufficiently testing. This research therefore concentrates on the control of the inverted pendulum with additional degrees of freedom as a testing demonstrator problem for learning control system experimentation. A flexible pole is used in place of a rigid one. The transverse displacement of the flexible pole has distributed elasticity and therefore infinite degrees of freedom. The dynamics of this new system are more complex as the system needs additional parameters to be defined due to the pole's elastic deflection. This problem also has many of the significant features associated with flexible robots with lightweight links as applied in manufacturing. Novel neural network and fuzzy control systems are presented that control such a system in real time in one of its modes of vibration. A fuzzy-genetic approach is also demonstrated that allows the creation of fuzzy control systems without the use of extensive knowledge. PMID:18256010

  8. Experimental Results in Support of Simulating Progressive Crush in Carbon-Fiber Textile Composites

    SciTech Connect

    DeTeresa, S J; Allison, L M; Cunningham, B J; Freeman, DC; Saculla, M D; Sanchez, R J; Winchester, S W

    2001-04-02

    This report summarizes the findings of an experimental program conducted to support the modeling of the crush behavior of triaxial braid carbon fiber composites. The matrix material as well as braided panels and tubes were characterized in order to determine material properties, to assess failure modes, and to provide a test bed for new analytical and numerical tools developed specifically for braided composites. The matrix material selected by the ACC was an epoxy vinyl ester (Ashland Hetron 922). Tensile tests were used to compare two formulations-one used by the ACC and one recommended by the resin supplier. The latter was a faster reacting system and gelled in one-third the time of the ACC formulation. Both formulations had an average elongation at failure that was only half of the resin supplier's reported value. Only one specimen of each type came close to the reported elongation value and it was shown that failure invariably initiated at both surface and internal defects. Overall, the tensile properties of the two formulations were nearly identical, but those of the ACC system were more consistent. The properties of the ACC matrix formulation were measured in tension, shear, and compression and the average properties obtained in these tests are summarized.

  9. Modeling and experimental results for condensing supercritical CO2 power cycles.

    SciTech Connect

    Wright, Steven Alan; Conboy, Thomas M.; Radel, Ross F.; Rochau, Gary Eugene

    2011-01-01

    This Sandia supported research project evaluated the potential improvement that 'condensing' supercritical carbon dioxide (S-CO{sub 2}) power cycles can have on the efficiency of Light Water Reactors (LWR). The analytical portion of research project identified that a S-CO{sub 2} 'condensing' re-compression power cycle with multiple stages of reheat can increase LWR power conversion efficiency from 33-34% to 37-39%. The experimental portion of the project used Sandia's S-CO{sub 2} research loop to show that the as designed radial compressor could 'pump' liquid CO{sub 2} and that the gas-cooler's could 'condense' CO{sub 2} even though both of these S-CO{sub 2} components were designed to operate on vapor phase S-CO{sub 2} near the critical point. There is potentially very high value to this research as it opens the possibility of increasing LWR power cycle efficiency, above the 33-34% range, while lowering the capital cost of the power plant because of the small size of the S-CO{sub 2} power system. In addition it provides a way to incrementally build advanced LWRs that are optimally designed to couple to S-CO{sub 2} power conversion systems to increase the power cycle efficiency to near 40%.

  10. Experimental results of underwater cooperative source localization using a single acoustic vector sensor.

    PubMed

    Felisberto, Paulo; Rodriguez, Orlando; Santos, Paulo; Ey, Emanuel; Jesus, Sérgio M

    2013-01-01

    This paper aims at estimating the azimuth, range and depth of a cooperative broadband acoustic source with a single vector sensor in a multipath underwater environment, where the received signal is assumed to be a linear combination of echoes of the source emitted waveform. A vector sensor is a device that measures the scalar acoustic pressure field and the vectorial acoustic particle velocity field at a single location in space. The amplitudes of the echoes in the vector sensor components allow one to determine their azimuth and elevation. Assuming that the environmental conditions of the channel are known, source range and depth are obtained from the estimates of elevation and relative time delays of the different echoes using a ray-based backpropagation algorithm. The proposed method is tested using simulated data and is further applied to experimental data from the Makai'05 experiment, where 8-14 kHz chirp signals were acquired by a vector sensor array. It is shown that for short ranges, the position of the source is estimated in agreement with the geometry of the experiment. The method is low computational demanding, thus well-suited to be used in mobile and light platforms, where space and power requirements are limited. PMID:23857257

  11. Solid-state dynamic nuclear polarization at 263 GHz: spectrometer design and experimental results.

    PubMed

    Rosay, Melanie; Tometich, Leo; Pawsey, Shane; Bader, Reto; Schauwecker, Robert; Blank, Monica; Borchard, Philipp M; Cauffman, Stephen R; Felch, Kevin L; Weber, Ralph T; Temkin, Richard J; Griffin, Robert G; Maas, Werner E

    2010-06-14

    Dynamic Nuclear Polarization (DNP) experiments transfer polarization from electron spins to nuclear spins with microwave irradiation of the electron spins for enhanced sensitivity in nuclear magnetic resonance (NMR) spectroscopy. Design and testing of a spectrometer for magic angle spinning (MAS) DNP experiments at 263 GHz microwave frequency, 400 MHz (1)H frequency is described. Microwaves are generated by a novel continuous-wave gyrotron, transmitted to the NMR probe via a transmission line, and irradiated on a 3.2 mm rotor for MAS DNP experiments. DNP signal enhancements of up to 80 have been measured at 95 K on urea and proline in water-glycerol with the biradical polarizing agent TOTAPOL. We characterize the experimental parameters affecting the DNP efficiency: the magnetic field dependence, temperature dependence and polarization build-up times, microwave power dependence, sample heating effects, and spinning frequency dependence of the DNP signal enhancement. Stable system operation, including DNP performance, is also demonstrated over a 36 h period. PMID:20449524

  12. Some experimental and theoretical results on the anodic patterns in plasma discharge

    SciTech Connect

    Gurlui, S.; Agop, M.; Strat, M.; Strat, Georgeta; Bacaita, Simona; Cerepaniuc, Adina

    2006-06-15

    The dynamics of an interface plasma-plasma self-structured as a double anodic layer using the fractal space-time theory is established. So, for the fractal dimension D=2, the Schroedinger 'fluid' is obtained as an irrotational movement of a Navier-Stokes fluid with an imaginary viscosity coefficient. In the deterministic case, the anodic double layer is described by a set of diffusion-reaction equations, a situation in which the equal diffusion curves are of the Koch-type and the self-structuring is given by means of the coherence of the electron-ion pairs. In the nondeterministic case, the anodic double layer is described by a set of time-dependent Schroedinger-type equations and the self-structuring is given by means of the negative differential resistance and the pulsation-potential linear dependence. Through the spontaneous symmetry breaking the Langmuir's relations, the distributions of the potential field and charge densities have been obtained. The model was verified by means of our experimental data too.

  13. Experimental Results of Underwater Cooperative Source Localization Using a Single Acoustic Vector Sensor

    PubMed Central

    Felisberto, Paulo; Rodriguez, Orlando; Santos, Paulo; Ey, Emanuel; Jesus, Sérgio M.

    2013-01-01

    This paper aims at estimating the azimuth, range and depth of a cooperative broadband acoustic source with a single vector sensor in a multipath underwater environment, where the received signal is assumed to be a linear combination of echoes of the source emitted waveform. A vector sensor is a device that measures the scalar acoustic pressure field and the vectorial acoustic particle velocity field at a single location in space. The amplitudes of the echoes in the vector sensor components allow one to determine their azimuth and elevation. Assuming that the environmental conditions of the channel are known, source range and depth are obtained from the estimates of elevation and relative time delays of the different echoes using a ray-based backpropagation algorithm. The proposed method is tested using simulated data and is further applied to experimental data from the Makai'05 experiment, where 8–14 kHz chirp signals were acquired by a vector sensor array. It is shown that for short ranges, the position of the source is estimated in agreement with the geometry of the experiment. The method is low computational demanding, thus well-suited to be used in mobile and light platforms, where space and power requirements are limited. PMID:23857257

  14. Solid-state dynamic nuclear polarization at 263 GHz: spectrometer design and experimental results

    PubMed Central

    Rosay, Melanie; Tometich, Leo; Pawsey, Shane; Bader, Reto; Schauwecker, Robert; Blank, Monica; Borchard, Philipp M.; Cauffman, Stephen R.; Felch, Kevin L.; Weber, Ralph T.; Temkin, Richard J.; Griffin, Robert G.; Maas, Werner E.

    2015-01-01

    Dynamic Nuclear Polarization (DNP) experiments transfer polarization from electron spins to nuclear spins with microwave irradiation of the electron spins for enhanced sensitivity in nuclear magnetic resonance (NMR) spectroscopy. Design and testing of a spectrometer for magic angle spinning (MAS) DNP experiments at 263 GHz microwave frequency, 400 MHz 1H frequency is described. Microwaves are generated by a novel continuous-wave gyrotron, transmitted to the NMR probe via a transmission line, and irradiated on a 3.2 mm rotor for MAS DNP experiments. DNP signal enhancements of up to 80 have been measured at 95 K on urea and proline in water–glycerol with the biradical polarizing agent TOTAPOL. We characterize the experimental parameters affecting the DNP efficiency: the magnetic field dependence, temperature dependence and polarization build-up times, microwave power dependence, sample heating effects, and spinning frequency dependence of the DNP signal enhancement. Stable system operation, including DNP performance, is also demonstrated over a 36 h period. PMID:20449524

  15. Experimental cavity pressure measurements at subsonic and transonic speeds. Static-pressure results

    NASA Technical Reports Server (NTRS)

    Plentovich, E. B.; Stallings, Robert L., Jr.; Tracy, M. B.

    1993-01-01

    An experimental investigation was conducted to determine cavity flow-characteristics at subsonic and transonic speeds. A rectangular box cavity was tested in the Langley 8-Foot Transonic Pressure Tunnel at Mach numbers from 0.20 to 0.95 at a unit Reynolds number of approximately 3 x 10(exp 6) per foot. The boundary layer approaching the cavity was turbulent. Cavities were tested over a range of length-to-depth ratios (l/h) of 1 to 17.5 for cavity width-to-depth ratios of 1, 4, 8, and 16. Fluctuating- and static-pressure data in the cavity were obtained; however, only static-pressure data is analyzed. The boundaries between the flow regimes based on cavity length-to-depth ratio were determined. The change to transitional flow from open flow occurs at l/h at approximately 6-8 however, the change from transitional- to closed-cavity flow occurred over a wide range of l/h and was dependent on Mach number and cavity configuration. The change from closed to open flow as found to occur gradually. The effect of changing cavity dimensions showed that if the vlaue of l/h was kept fixed but the cavity width was decreased or cavity height was increased, the cavity pressure distribution tended more toward a more closed flow distribution.

  16. Heat transfer with very high free-stream turbulence. I - Experimental data. II - Analysis of results

    NASA Technical Reports Server (NTRS)

    Maciejewski, P. K.; Moffat, R. J.

    1992-01-01

    Boundary layer heat transfer with very high freestream turbulence is investigated. The problem is studied experimentally by placing a constant-temperature heat transfer surface at various locations in the margin of a turbulent free jet and measuring both the surface heat transfer rate and the turbulence in the freestream. Freestream turbulent fluctuations 20 to 60 percent relative to the mean velocity augment heat transfer 1.8 to 4 times that which would be predicted locally using accepted correlations for turbulent boundary layers at the same Reynolds number. The correlations of Simonich and Bradshaw (1989), Pedisius et al. (1983), and Blair (1983) each fail to describe the present data. For flows over flat surfaces in air with very high freestream turbulence, greater than 0.2, u-prime determines h. A new heat transfer parameter, St-prime, characterizes turbulent boundary layer heat transfer with freestream turbulence on the domain 0-0.65 to within +/- 15 percent for high Reynolds number flows with uniform thermal boundary conditions.

  17. Results of a preliminary experimental investigation of a vapor transport fuel pin

    NASA Technical Reports Server (NTRS)

    Lanzo, C. D.

    1972-01-01

    In-Pile experimental tests were conducted on two fuel pins mounted side-by-side in a holder assembly. The fuel pins consisted of stacked fully enriched UO2 pellets enclosed in a type 316 stainless steel clad 1/2 inch outside diameter and 3 inches in length. Each fuel pin contained four pellets for a total of 22 grams of fuel weight. The experiment was operated to maintain the maximum clad temperature at 395 K corresponding to a fuel temperature at the central void surface of 2350 K. Total primary coolant water flow past the pin holder was calculated to be 110 gallons per minute. Forty-four gallons per minute at a velocity of 36.5 feet per second flowed around each fuel pin. Calculations indicated the maximum heat flux was at the point of the highest temperature and was equal to 0.24 kW/sq cm or 7.62 Btu/hr sq ft. A series of high resolution neutron radiographs of the nuclear fueled vapor transport capsule was taken. The thermal neutrons emitted from the core of the 60 megawatt Plum Brook reactor facility were used.

  18. Bulk Modulus of Sc2O3: Ab initio Calculations and Experimental Results

    SciTech Connect

    S Barzilai; I Halvey; O Yeheskel

    2011-12-31

    The bulk modulus of scandia is evaluated by ab initio calculation, based on density functional theory, and compared with bulk modulus measurement on nearly fully dense scandia and with the value attained from the equation of state based on diamond anvil cell measurements. The current results are in the upper range of the bulk moduli results in the literature. The scatter in the literature results might be explained by the differences in the specific volumes of the measured and calculated cases. For the specific volume of 59.65{+-}0.07 {angstrom}{sup 3} the average measured isothermal bulk modulus of scandia from the present study and recent literature results is 188{+-}10 GPa.

  19. Experimental Results for Over-the-Horizon Planetary Exploration using a LIDAR sensor

    E-print Network

    Rekleitis, Ioannis

    -priori the detailed geometry of the environment, and thus will not be able to select way-points for the rovers contains results from a representative experiment and the paper concludes with lessons learned and future

  20. Investigations of a Combustor Using a 9-Point Swirl-Venturi Fuel Injector: Recent Experimental Results

    NASA Technical Reports Server (NTRS)

    Hicks, Yolanda R.; Heath, Christopher M.; Anderson, Robert C.; Tacina, Kathleen M.

    2012-01-01

    This paper explores recent results obtained during testing in an optically-accessible, JP8-fueled, flame tube combustor using baseline Lean Direct Injection (LDI) research hardware. The baseline LDI geometry has nine fuel/air mixers arranged in a 3 x 3 array. Results from this nine-element array include images of fuel and OH speciation via Planar Laser-Induced Fluorescence (PLIF), which describe fuel spray pattern and reaction zones. Preliminary combustion temperatures derived from Stokes/Anti-Stokes Spontaneous Raman Spectroscopy are also presented. Other results using chemiluminescence from major combustion radicals such as CH* and C2* serve to identify the primary reaction zone, while OH PLIF shows the extent of reaction further downstream. Air and fuel velocities and fuel drop size results are also reported.

  1. Horizontal convection in water heated by infrared radiation and cooled by evaporation: scaling analysis and experimental results

    NASA Astrophysics Data System (ADS)

    Wåhlin, A. K.; Johansson, A. M.; Aas, E.; Broström, G.; Weber, J. E. H.; Grue, J.

    2010-03-01

    An experimental study of horizontal convection with a free surface has been conducted. Fresh water was heated from above by an infrared lamp placed at one end of a tank, and cooled by evaporation as the water moved away from the heat source. The heat radiated from the lamp was absorbed in a thin (less than 1 mm) layer next to the surface, and then advected and diffused away from the lamp region. Latent heat loss dominated the surface cooling processes and accounted for at least 80% of the energy loss. The velocity and temperature fields were recorded with PIV technology, thermometers and an infrared camera. In similarity with previous horizontal convection experiments the measurements showed a closed circulation with a gradually cooling surface current moving away from the lamp. Below the surface current the water was stably stratified with a comparatively thick and slow return current. The thickness and speed, and hence the mass transport, of the surface- and the return current increased with distance from the lamp. The latent cooling at the free surface gives a heat flux which increases with the temperature difference between the surface water and the air above it. Hence the surface temperature relaxes towards an equilibrium value, for which the heat flux is zero. The main new result is a scaling law, taking into account this relaxation boundary condition for the surface temperature. The new scaling includes a (relaxation) length scale for the surface temperature, equivalent to the distance the surface current travels before it has lost the heat that was gained underneath the lamp. The length scale increases with the forcing strength and the (molecular) thermal diffusivity but decreases with the strength of the relaxation. Numerical simulations of this problem for a shallow tank have also been performed. The velocity and temperature in the laboratory and numerical experiments agree with the scaling laws in the upper part of the tank, but not in the lower.

  2. INTERACTION OF A 24 GEV PROTON BEAM IWHT A MUON COLLIDER MERCURY JET TARGET EXPERIMENTAL RESULTS AND THERMODYNAMIC ASSESSMENT.

    SciTech Connect

    SIMOS,N.; KIRK,H.; FINFROCK,C.; GREENE,G.; LUDEWIG,H.; MCDONALD,K.; MOKHOV,N.

    2001-11-11

    A muon collider or a neutrino factory based on a muon storage ring require intense beams of muons that can be generated by a 1-4 MW proton beam incident on a moving target inside a 20-T solenoid magnet, with a mercury jet as a preferred example. This paper addresses the thermodynamic interaction of the intense proton beam with the proposed mercury jet target, and the consequences of the generated pressure waves on the target integrity. Specifically, a 24 GeV proton beam with approximately 16 TP (1 TP = 10{sup 12} protons) per pulse and a pulse length of 2 ns will interact with a 1 cm diameter mercury jet within the 20-Tesla magnetic field. In one option, a train of six such proton pulses is to be delivered on target within 2 {micro}s, in which case the state of the mercury jet following the interaction with each pulse is critical. Using the equation of state for mercury from the SESAME library, in combination with the energy deposition rates calculated the by the hadron interaction code MARS, the induced 3-D pressure field in the target is estimated. The consequent pressure wave propagation and attenuation in the mercury jet is calculated using a transient analysis based on finite element modeling, and the state of the mercury jet at the time of arrival of the subsequent pulse is assessed. Issues associated with the use of a liquid metal jet as a target candidate are addressed. Lastly, some experimental results from the BNL E951 experiment are presented and discussed.

  3. Clinical pathology results from cranes with experimental West Nile Virus infection

    USGS Publications Warehouse

    Olsen, Glenn H.

    2011-01-01

    Sandhill cranes (Grus canadensis) were vaccinated for and then challenged with West Nile virus. Resulting titers demonstrated protection in the vaccinated-challenged cranes as compared to the unvaccinated-challenged cranes. Clinical pathology results showed challenged cranes, whether vaccinated or not, had a decrease in their hematocrits and an elevation of 2.5-fold in their white blood cell counts as compared to unchallenged control sandhill cranes. No differences were apparent in the differential counts of heterophils and lymphocytes.

  4. An experimental search strategy retrieves more precise results than PubMed and Google for questions about medical interventions

    PubMed Central

    Dylla, Daniel P.; Megison, Susan D.

    2015-01-01

    Objective. We compared the precision of a search strategy designed specifically to retrieve randomized controlled trials (RCTs) and systematic reviews of RCTs with search strategies designed for broader purposes. Methods. We designed an experimental search strategy that automatically revised searches up to five times by using increasingly restrictive queries as long at least 50 citations were retrieved. We compared the ability of the experimental and alternative strategies to retrieve studies relevant to 312 test questions. The primary outcome, search precision, was defined for each strategy as the proportion of relevant, high quality citations among the first 50 citations retrieved. Results. The experimental strategy had the highest median precision (5.5%; interquartile range [IQR]: 0%–12%) followed by the narrow strategy of the PubMed Clinical Queries (4.0%; IQR: 0%–10%). The experimental strategy found the most high quality citations (median 2; IQR: 0–6) and was the strategy most likely to find at least one high quality citation (73% of searches; 95% confidence interval 68%–78%). All comparisons were statistically significant. Conclusions. The experimental strategy performed the best in all outcomes although all strategies had low precision. PMID:25922798

  5. An experimental search strategy retrieves more precise results than PubMed and Google for questions about medical interventions.

    PubMed

    Badgett, Robert G; Dylla, Daniel P; Megison, Susan D; Harmon, E Glynn

    2015-01-01

    Objective. We compared the precision of a search strategy designed specifically to retrieve randomized controlled trials (RCTs) and systematic reviews of RCTs with search strategies designed for broader purposes. Methods. We designed an experimental search strategy that automatically revised searches up to five times by using increasingly restrictive queries as long at least 50 citations were retrieved. We compared the ability of the experimental and alternative strategies to retrieve studies relevant to 312 test questions. The primary outcome, search precision, was defined for each strategy as the proportion of relevant, high quality citations among the first 50 citations retrieved. Results. The experimental strategy had the highest median precision (5.5%; interquartile range [IQR]: 0%-12%) followed by the narrow strategy of the PubMed Clinical Queries (4.0%; IQR: 0%-10%). The experimental strategy found the most high quality citations (median 2; IQR: 0-6) and was the strategy most likely to find at least one high quality citation (73% of searches; 95% confidence interval 68%-78%). All comparisons were statistically significant. Conclusions. The experimental strategy performed the best in all outcomes although all strategies had low precision. PMID:25922798

  6. Design and experimental results on a terawatt magnetically controlled plasma opening switch

    SciTech Connect

    Savage, M.E.; Simpson, W.W.; Mendel, C.W. Jr.; McDaniel, D.H.; Levine, J.S.; Tucker, T.S.

    1998-05-01

    The magnetically controlled plasma opening switch (MCPOS) is an advanced plasma opening switch that utilizes magnetic fields to improve operation. Magnetic fields always dominate terawatt, pulsed power plasma opening switches. For that reason, the MCPOS uses controlled applied magnetic fields with magnitude comparable to the self-magnetic field of the storage inductor. One applied field holds the plasma in place while energy accumulates in the storage inductor, then another applied field pushes the plasma away from the cathode to allow energy to flow downstream. Over a ten month period, an MCPOS was designed, built, and tested on DECADE Module 2 at Physics International. The peak drive current was 1.8 MA in 250 ns. The output parameters were up to 1 MA into an electron beam load. The radiation temporal pulse width averaged 60 nanoseconds full-width at half-maximum. The peak load voltage ranged from one to two megavolts. The experiments demonstrated efficient power flow through a long, low-impedance magnetically insulated transmission line between the magnetically controlled plasma opening switch and the load.

  7. Numerical simulation of cross-flow-induced fluidelastic vibration of tube arrays and comparison with experimental results

    SciTech Connect

    Eisinger, F.L. ); Rao, M.S.M. ); Steininger, D.A. ); Haslinger, K.H. )

    1995-02-01

    Tube arrays exposed to air, gas or liquid cross-flow can vibrate due to vortex-shedding, turbulence, or fluidelastic instability. The major emphasis of this paper is on the phenomenon of fluidelastic instability (or fluidelastic vibration). A numerical model is applied to the simulation of fluidelastic vibration of representative tubes in a tube bundle, based on S. S. Chen's unsteady flow theory. The results are validated against published data based on linear cases. The model is then applied to a nonlinear structure of a U-bend tube bundle with clearances at supports, and the computed results compared to those obtained by experimental testing. The numerical studies were performed using the ABAQUS-EPGEN finite element code using a special subroutine incorporating fluidelastic forces. It is shown that the results of both the linear and nonlinear modeling are in good agreement with experimental data.

  8. A comparison of experimental and theoretical results for labyrinth gas seals with honeycomb stators. M.S. Thesis

    NASA Technical Reports Server (NTRS)

    Hawkins, Lawrence Allen

    1988-01-01

    Experimental results for the rotordynamic stiffness and damping coefficients of a labyrinth -rotor honeycomb-stator seal are presented. The coefficients are compared to the coefficients of a labyrinth-rotor smooth-stator seal having the same geometry. The coefficients are compared to analytical results from a two-control-volume compressible flow model. The experimental results show that the honeycomb stator configuration is more stable than the smooth stator configuration at low rotor speeds. At high rotor speeds and low clearance, the smooth stator seal is more stable. The theoretical model predicts the cross-coupled stiffness of the honeycomb stator seal correctly within 25 percent of measured values. The model provides accurate predictions of direct damping for large clearance seals. Overall, the model does not perform as well for low clearance seals as for high clearance seals.

  9. Verification of a general-purpose laminated composite shell element implementation - Comparisons with analytical and experimental results

    NASA Astrophysics Data System (ADS)

    Murray, Yvonne D.; Schwer, Leonard E.

    1993-04-01

    The constitutive behavior of a laminated shell element, implemented in a nonlinear finite element code, is verified by analyzing a series of analytical and experimental results. Comparisons between the laminated shell model and analytical results available in the literature verify the implementation of the model for the membrane response, bending response with and without transverse shear, and the coupled response between the membrane and bending modes. The theoretical basis of the laminated shell model is verified by analyzing an impulsively loaded ring test. Our purpose in presenting this set of analytical and experimental results is to provide other researchers and developers of laminated composite shell elements with an initial source of comparative data for both their element verification and performance relative to the DYNA3D implementation.

  10. Experimental results for labyrinth gas seals with honeycomb stators - Comparisons to smooth-stator seals and theoretical predictions

    NASA Technical Reports Server (NTRS)

    Hawkins, Larry; Childs, Dara; Hale, Keith

    1989-01-01

    Experimental measurements are presented for the rotordynamic stiffness and damping coefficients of a teeth-on-rotor labyrinth seal with a honeycomb stator. Inlet circumferential velocity, inlet pressure, rotor speed, and seal clearance are primary variables. Results are compared to data for teeth-on-rotor labyrinth seals with smooth stators and to analytical predictions from a two-control-volume compressible flow model. The experimental results show that the honeycomb-stator configuration is more stable than the smooth-stator configuration at low rator speeds. At high rotor speeds, the stator surface does not affect stability. The theoretical model predicts the cross-coupled stiffness of the honeycomb-stator seal correctly within 25 percent of measured values. The model provides accurate predictions of direct damping for large clearance seals; however, the model predictions and test results diverge with increasing running speed. Overall, the model does not perform as well for low clearance seals as for high clearance seals.

  11. Hidden modes in open disordered media: analytical, numerical, and experimental results

    NASA Astrophysics Data System (ADS)

    Bliokh, Yury P.; Freilikher, Valentin; Shi, Z.; Genack, A. Z.; Nori, Franco

    2015-11-01

    We explore numerically, analytically, and experimentally the relationship between quasi-normal modes (QNMs) and transmission resonance (TR) peaks in the transmission spectrum of one-dimensional (1D) and quasi-1D open disordered systems. It is shown that for weak disorder there exist two types of the eigenstates: ordinary QNMs which are associated with a TR, and hidden QNMs which do not exhibit peaks in transmission or within the sample. The distinctive feature of the hidden modes is that unlike ordinary ones, their lifetimes remain constant in a wide range of the strength of disorder. In this range, the averaged ratio of the number of transmission peaks {N}{{res}} to the number of QNMs {N}{{mod}}, {N}{{res}}/{N}{{mod}}, is insensitive to the type and degree of disorder and is close to the value \\sqrt{2/5}, which we derive analytically in the weak-scattering approximation. The physical nature of the hidden modes is illustrated in simple examples with a few scatterers. The analogy between ordinary and hidden QNMs and the segregation of superradiant states and trapped modes is discussed. When the coupling to the environment is tuned by an external edge reflectors, the superradiance transition is reproduced. Hidden modes have been also found in microwave measurements in quasi-1D open disordered samples. The microwave measurements and modal analysis of transmission in the crossover to localization in quasi-1D systems give a ratio of {N}{{res}}/{N}{{mod}} close to \\sqrt{2/5}. In diffusive quasi-1D samples, however, {N}{{res}}/{N}{{mod}} falls as the effective number of transmission eigenchannels M increases. Once {N}{{mod}} is divided by M, however, the ratio {N}{{res}}/{N}{{mod}} is close to the ratio found in 1D.

  12. An experimental study of vibration based energy harvesting in dynamically tailored structures with embedded acoustic black holes

    NASA Astrophysics Data System (ADS)

    Zhao, Liuxian; Conlon, Stephen C.; Semperlotti, Fabio

    2015-06-01

    In this paper, we present an experimental investigation on the energy harvesting performance of dynamically tailored structures based on the concept of embedded acoustic black holes (ABHs). Embedded ABHs allow tailoring the wave propagation characteristics of the host structure creating structural areas with extreme levels of energy density. Experiments are conducted on a tapered plate-like aluminum structure with multiple embedded ABH features. The dynamic response of the structure is tested via laser vibrometry in order to confirm the vibration localization and the passive wavelength sweep characteristic of ABH embedded tapers. Vibrational energy is extracted from the host structure and converted into electrical energy by using ceramic piezoelectric discs bonded on the ABHs and shunted on an external electric circuit. The energy harvesting performance is investigated both under steady state and transient excitation. The experimental results confirm that the dynamic tailoring produces a drastic increase in the harvested energy independently from the nature of the excitation input.

  13. Initial experimental results from a laboratory size beam plasma discharge device

    NASA Technical Reports Server (NTRS)

    Konradi, A.; Bernstein, W.; Bulgher, D. L.; Garrity, J. O.; Winkler, J. L.

    1983-01-01

    A laboratory beam plasma discharge (BPD) device produced BPD in N2, A, and He. All features of the BPD observed in the device agree with those observed in a large vacuum chamber. The empirical ignition criteria determined in the large chamber apply in the small device but do not fit when used for extrapolation between the large and the small geometry. At some energies and magnetic fields beam currents exist for which the total light output in the BPD state varies by a factor of 2 with a factor of 6 pressure variation. Above 0.0001 torr the BPD width is pressure independent but for lower pressures it expands by as much as a factor of 4 at 0.00002 torr.

  14. Experimental Results from an Antineutrino Detector for Cooperative Monitoring of Nuclear Reactors

    SciTech Connect

    Bowden, N S; Bernstein, A; Allen, M; Brennan, J S; Cunningham, M; Estrada, J K; Greaves, C R; Hagmann, C; Lund, J; Mengesha, W; Weinbeck, T D; Winant, C D

    2006-09-18

    Our collaboration has designed, installed, and operated a compact antineutrino detector at a nuclear power station, for the purpose of monitoring the power and plutonium content of the reactor core. This paper focuses on the basic properties and performance of the detector. We describe the site, the reactor source, and the detector, and provide data that clearly show the expected antineutrino signal. Our data and experience demonstrate that it is possible to operate a simple, relatively small, antineutrino detector near a reactor, in a non-intrusive and unattended mode for months to years at a time, from outside the reactor containment, with no disruption of day-to-day operations at the reactor site. This unique real-time cooperative monitoring capability may be of interest for the International Atomic Energy Agency (IAEA) reactor safeguards program and similar regimes.

  15. Structural stability of thermoelectric diffusion barriers: Experimental results and first principles calculations

    NASA Astrophysics Data System (ADS)

    Hsu, Hsiao-Hsuan; Cheng, Chun-Hu; Lin, Yu-Li; Chiou, Shan-Haw; Huang, Chiung-Hui; Cheng, Chin-Pao

    2013-07-01

    This study demonstrates the feasibility of producing a tantalum nitride (TaN) thin film as a diffusion barrier and buffer layer for p-type bismuth telluride [(Bi,Sb)2Te3] thermoelectric devices. A network of TaN with nitrogen (N) incorporation is structurally more stable on (Bi,Sb)2Te3 than the conventional Ni diffusion barrier because of less inter-diffusion and a greater likelihood of stoichiometry in the TaN/(Bi,Sb)2Te3 interface. The atomic inter-diffusion between the barrier layers and (Bi,Sb)2Te3 was evaluated in terms of interface adhesion energy using nanoscratching, and proved with first-principles calculations.

  16. Experimental results from an antineutrino detector for cooperative monitoring of nuclear reactors

    NASA Astrophysics Data System (ADS)

    Bowden, N. S.; Bernstein, A.; Allen, M.; Brennan, J. S.; Cunningham, M.; Estrada, J. K.; Greaves, C. M. R.; Hagmann, C.; Lund, J.; Mengesha, W.; Weinbeck, T. D.; Winant, C. D.

    2007-03-01

    Our collaboration has designed, installed, and operated a compact antineutrino detector at a nuclear power station, for the purpose of monitoring the power and plutonium content of the reactor core. This paper focuses on the basic properties and performance of the detector. We describe the site, the reactor source, and the detector, and provide data that clearly show the expected antineutrino signal. Our data and experience demonstrate that it is possible to operate a simple, relatively small, antineutrino detector near a reactor, in a non-intrusive and unattended mode for months to years at a time, from outside the reactor containment, with no disruption of day-to-day operations at the reactor site. This unique real-time cooperative monitoring capability may be of interest for the International Atomic Energy Agency (IAEA) reactor safeguards program and similar regimes.

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

    E-print Network

    Illinois at Urbana-Champaign, University of

    modeled by adding damped linear oscillator terms to describe the effect of the shell,22 while later models postexcitation signal results Daniel A. Kinga) Department of Mechanical Science and Engineering, University microbubbles are compared with the Marmottant theoretical model for large amplitude oscillations of ultrasound

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

    E-print Network

    Scharer, John E.

    densities have been measured for a periodic copper knife-edge cathode to compare with the TMM model result-Nordheim FN and Richardson- Laue-Dushman RLD laws,1­4 respectively. The supply electrons obey the Sommerfeld is the Boltzmann constant, and T is the background temperature. In the original FN law,1 the image charge potential

  19. Experimental results on QCD (Quantum Chromodynamics) from e/sup +/e/sup -/ annihilation

    SciTech Connect

    de Boer, W.

    1987-09-01

    A review is given on QCD results from studying e/sup +/e/sup -/ annihilation with the PEP and PETRA storage rings with special emphasis on jet physics and the determination of the strong coupling constant ..cap alpha../sub s/. 92 refs., 28 figs., 3 tabs.

  20. Hypersonic research engine/aerothermodynamic integration model, experimental results. Volume 2: Mach 6 performance

    NASA Technical Reports Server (NTRS)

    Andrews, E. H., Jr.; Mackley, E. A.

    1976-01-01

    Computer program performance results of a Mach 6 hypersonic research engine during supersonic and subsonic combustion modes were presented. The combustion mode transition was successfully performed, exit surveys made, and effects of altitude, angle of attack, and inlet spike position were determined during these tests.

  1. Implications of Bt Traits on Mycotoxin Contamination in Maize: Overview and Recent Experimental Results

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Methods are becoming available to control mycotoxin-producing fungi in pre-harvest crops, including biocontrol and host plant resistance. While published reports since 1999 have associated Bt expression in corn with reduced mycotoxin levels, subsequent field results have been inconsistent. There i...

  2. Results from an Experimental Study about Reinforcements Employed in Early Training

    ERIC Educational Resources Information Center

    Aparicio, Maria Teresa Sanz

    2004-01-01

    The Down's syndrome population presents a social quotient higher than its intelligence quotient, the main characteristic of its personality and because of the pronounced hypotony suffered by them, principally in the first years of life. This report shows the results of a study carried out about differential acquisitions of two groups of trisomy-21…

  3. Resource evaluation of marine gas hydrate deposits using the seafloor compliance method: Experimental methods and results

    NASA Astrophysics Data System (ADS)

    Willoughby, Eleanor Colleen

    My purpose is to develop a new geophysical tool capable of assessing offshore methane hydrate deposits; something that traditional seismological techniques have not been able to do effectively. Methane hydrate is an ice-like clathrate trapping methane compactly. Natural deposits are estimated to account for 53% of the total organic carbon in the Earth, twice as much carbon as all other fossil fuels combined. Methane is not only an immense fuel resource, it is also a powerful greenhouse gas. Clearly the detection and evaluation of the extent of sub-seafloor methane hydrate deposits is of great importance, not only to determine the potential for resource recovery but also for natural hazard assessment. I applied a relatively new and novel technique: seafloor compliance. Wind-induced surface gravity waves create a pressure field which propagates downward to palpitate the seafloor. Compliance is the transfer function between this pressure, which is of the order of 1 Pa and the associated vertical deformation, of the order of microns. Compliance measurements are made by lowering a self-levelling gravimeter, differential pressure gauge and data logger to the sea floor, where simultaneous time series of pressure and acceleration are recorded. Sea-floor compliance data can be inverted to yield a profile of shear modulus with depth and by inference hydrate content because the shear modulus is a strong function of sediment stiffness caused by hydrate cementation. In conjunction with Scintrex Ltd., I adapted their gravimeter for seafloor use, and experimentally ascertained the frequency calibration of both it and the differential pressure gauge. I gathered seafloor compliance data on five separate research cruises off the coast of Vancouver Island. The data provide a new estimate for shear velocity in the ocean bottom sediments of the region, something quite difficult to achieve with traditional methods, but they do not as of yet uniquely resolve the hydrate layer. I have established how best to apply the method, and that it is consistent with other available geophysical data. When inverted jointly with seismic data, compliance can produce an estimate of the total mass of a hydrate deposit.

  4. Mechanism of amorphous silica particles precipitation: simulation approach compared to experimental results

    NASA Astrophysics Data System (ADS)

    Noguera, Claudine; Fritz, Bertrand; Clement, Alain

    2015-04-01

    Despite its importance in numerous industrial and natural processes, many unsolved questions remain regarding the mechanism of silica precipitation in aqueous solutions: order of the reaction, role of silica oligomers, existence of an induction time and characteristics of the particle population. Beyond empirical approaches used in the past, we demonstrate that the classical nucleation theory associated to a size dependent growth law, as embedded in the NANOKIN code (1-3), allows a quantitative description of precipitation occurring under largely different experimental conditions : preexisting initial supersaturation in a large domain of temperature (5-150°C) and chemical composition (4), supersaturation reached by neutralization of a high pH silica solution (5) or by fast cooling (6). In that way, the mechanism of silica precipitation can be unraveled. We are able to discard the hypothesis of an induction time as an explanation for the plateaus observed in the saturation curves in these experiments. We challenge the role of oligomer incorporation at the growth stage to account for the observed rate laws and we stress the difference between the order of the growth law and the order of the total reaction rate. We also demonstrate that the characteristics of the particle population are strongly dependent on the way supersaturation is reached (7). Such a microscopic approach thus proves to be well suited to elucidate the mechanism of nanoparticle formation in natural and industrial contexts, involving silica, but also other mineral phases produced as nanoparticles (8). (1) Noguera C., Fritz B., Clément A. and Barronet A., J. Cryst. Growth, 2006, 297, 180. (2) Noguera C., Fritz B., Clément A. and Barronet A., J. Cryst. Growth, 2006, 297, 187. (3) Fritz B., Clément A., Amal Y. and Noguera C., Geochim. Cosmochim. Acta, 2009, 73, 1340. (4) Rothbaum, H.P. and Rohde A.G., J. Colloid Interf. Sci., 1979,71, 533. (5) Tobler D.J., Shaw S. and Benning L.G., Geochim. Cosmochim. Acta, 2009, 73, 5377. (6) Tobler D.J. and Benning L.G., Geochim. Cosmochim. Acta, 2013, 114, 156. (7) Noguera C., Fritz B., Clément A., submitted. (8) Fritz B., Clément A., Montes-Hernandez G. and Noguera C., CrystEngComm, 2013, 15, 3392.

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

    NASA Astrophysics Data System (ADS)

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

    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

  6. Experimental results from magnetized-jet experiments executed at the Jupiter Laser Facility

    NASA Astrophysics Data System (ADS)

    Manuel, M. J.-E.; Kuranz, C. C.; Rasmus, A. M.; Klein, S. R.; MacDonald, M. J.; Trantham, M. R.; Fein, J. R.; Belancourt, P. X.; Young, R. P.; Keiter, P. A.; Drake, R. P.; Pollock, B. B.; Park, J.; Hazi, A. U.; Williams, G. J.; Chen, H.

    2015-12-01

    Recent experiments at the Jupiter Laser Facility investigated magnetization effects on collimated plasma jets. Laser-irradiated plastic-cone-targets produced collimated, millimeter-scale plasma flows as indicated by optical interferometry. Proton radiography of these jets showed no indication of strong, self-generated magnetic fields, suggesting a dominantly hydrodynamic collimating mechanism. Targets were placed in a custom-designed solenoid capable of generating field strengths up to 5 T. Proton radiographs of the well-characterized B-field, without a plasma jet, suggested an external source of trapped electrons that affects proton trajectories. The background magnetic field was aligned with the jet propagation direction, as is the case in many astrophysical systems. Optical interferometry showed that magnetization of the plasma results in disruption of the collimated flow and instead produces a hollow cavity. This result is a topic of ongoing investigation.

  7. Plasma discharge in N2 + CH4 at low pressures - Experimental results and applications to Titan

    NASA Technical Reports Server (NTRS)

    Thompson, W. Reid; Henry, Todd J.; Schwartz, Joel M.; Khare, B. N.; Sagan, Carl

    1991-01-01

    Results are reported from laboratory continuous-flow plasma-discharge experiments designed to simulate the formation of hydrocarbons and nitriles from N2 and CH4 in the atmosphere of Titan. Gas-chromatography and mass-spectrometry data were obtained in experiments lasting up to 100 h at temperature 295 K and pressure 17 or 0.24 mbar, modeling (1) cosmic-ray-induced processes in the Titan troposphere and (2) processes related to stratospheric aurorae excited by energetic electrons and ions from the Saturn magnetosphere, respectively. The results are presented in extensive tables and graphs, and the 0.24-mbar yields are incorporated into an eddy-mixing model to give stratospheric column abundances and mole fractions in good agreement with Voyager IRIS observations.

  8. First experimental results at the gran sasso laboratory on cold nuclear fusion in titanium electrodes

    NASA Astrophysics Data System (ADS)

    Bertin, A.; Bruschi, M.; Capponi, M.; De Castro, S.; Marconi, U.; Moroni, C.; Piccinini, M.; Semprini-Cesari, N.; Trombini, A.; Vitale, A.; Zoccoli, A.; Czirr, J. B.; Jensen, G. L.; Jones, S. E.; Palmer, E. P.

    1990-06-01

    We present here the first results obtained at the Gran Sasso Laboratory on the neutron emission following the electrolytic infusion of deuterons into titanium electrodes. The measurements were carried out under a 4000-m water equivalent rock thickness, i.e., in an extremely reduced cosmic-radiation background. The neutrons were detected by proton-recoil liquid scintillation detectors, allowing a huge reduction of the local gamma-ray background. The results obtained provide a neutron emission rate comparable in size to the one recently reported by Jones et al. in an electrolysis experiment performed with a different apparatus in ordinary laboratory conditions. They provide more evidence in favor of low-level cold nuclear fusions in metals.

  9. Experimental Results of Hydrogen Slosh in a 62 Cubic Foot (1750 Liter) Tank

    NASA Technical Reports Server (NTRS)

    Moran, Matthew E.; Mcnelis, Nancy B.; Kudlac, Maureen T.; Haberbusch, Mark S.; Satornino, George A.

    1994-01-01

    Extensive slosh testing with liquid and slush hydrogen was conducted in a 62 cubic foot spherical tank to characterize the thermodynamic response of the system under normal gravity conditions. Slosh frequency and amplitude, pressurant type, ramp pressure, and ullage volume were parametrically varied to assess the effect of each of these parameters on the tank pressure and fluid/wall temperatures. A total of 91 liquid hydrogen and 62 slush hydrogen slosh tests were completed. Both closed tank tests and expulsions during sloshing were performed. This report presents and discusses highlights of the liquid hydrogen closed tank results in detail and introduces some general trends for the slush hydrogen tests. Summary comparisons between liquid and slush hydrogen slosh results are also presented.

  10. Operational results for the experimental DOE/NASA Mod-OA wind turbine project

    NASA Technical Reports Server (NTRS)

    Shaltens, R. K.; Birchenough, A. G.

    1983-01-01

    The Mod-OA wind turbine project which was to gain early experience in the operation of large wind turbines in a utility environment is discussed. The Mod-OA wind turbines were a first generation design, and even though not cost effective, the operating experience and performance characteristics had a significant effect on the design and development of the second and third generation machines. The Mod-OA machines were modified as a result of the operational experience, particularly the blade development and control system strategy. The results of study to investigate the interaction of a Mod-OA wind turbine with an isolated diesel generation system are discussed. The machine configuration, its advantages and disadvantages and the machine performance and availability are discussed.

  11. Hypersonic research engine/aerothermodynamic integration model, experimental results. Volume 1: Mach 6 component integration

    NASA Technical Reports Server (NTRS)

    Andrews, E. H., Jr.; Mackley, E. A.

    1976-01-01

    The NASA Hypersonic Research Engine (HRE) Project was initiated for the purpose of advancing the technology of airbreathing propulsion for hypersonic flight. A large component (inlet, combustor, and nozzle) and structures development program was encompassed by the project. The tests of a full-scale (18 in. diameter cowl and 87 in. long) HRE concept, designated the Aerothermodynamic Integration Model (AIM), at Mach numbers of 5, 6, and 7. Computer program results for Mach 6 component integration tests are presented.

  12. First PGAA and NAA experimental results from a compact high intensity D-D neutron generator

    NASA Astrophysics Data System (ADS)

    Reijonen, J.; Leung, K.-N.; Firestone, R. B.; English, J. A.; Perry, D. L.; Smith, A.; Gicquel, F.; Sun, M.; Koivunoro, H.; Lou, T.-P.; Bandong, B.; Garabedian, G.; Revay, Zs.; Szentmiklosi, L.; Molnar, G.

    2004-04-01

    High neutron output D-D neutron generators have been developed in the Plasma and Ion Source Technology Group in LBNL. A new facility has been build to enable testing and running these powerful generators. The co-axial neutron generator and the shielding/moderator structure are described in this presentation. Also presented are the first PGAA (Prompt Gamma Activation Analysis) and NAA (Neutron Activation Analysis) results measured in this neutron facility.

  13. Initial experimental results of a machine learning-based temperature control system for an RF gun

    E-print Network

    Edelen, A L; Milton, S V; Chase, B E; Crawford, D J; Eddy, N; Edstrom, D; Harms, E R; Ruan, J; Santucci, J K; Stabile, P

    2015-01-01

    Colorado State University (CSU) and Fermi National Accelerator Laboratory (Fermilab) have been developing a control system to regulate the resonant frequency of an RF electron gun. As part of this effort, we present initial test results for a benchmark temperature controller that combines a machine learning-based model and a predictive control algorithm. This is part of an on-going effort to develop adaptive, machine learning-based tools specifically to address control challenges found in particle accelerator systems.

  14. Experimental results for the rapid determination of the freezing point of fuels

    NASA Technical Reports Server (NTRS)

    Mathiprakasam, B.

    1984-01-01

    Two methods for the rapid determination of the freezing point of fuels were investigated: an optical method, which detected the change in light transmission from the disappearance of solid particles in the melted fuel; and a differential thermal analysis (DTA) method, which sensed the latent heat of fusion. A laboratory apparatus was fabricated to test the two methods. Cooling was done by thermoelectric modules using an ice-water bath as a heat sink. The DTA method was later modified to eliminate the reference fuel. The data from the sample were digitized and a point of inflection, which corresponds to the ASTM D-2386 freezing point (final melting point), was identified from the derivative. The apparatus was modifified to cool the fuel to -60 C and controls were added for maintaining constant cooling rate, rewarming rate, and hold time at minimum temperature. A parametric series of tests were run for twelve fuels with freezing points from -10 C to -50 C, varying cooling rate, rewarming rate, and hold time. Based on the results, an optimum test procedure was established. The results showed good agreement with ASTM D-2386 freezing point and differential scanning calorimetry results.

  15. Experimental results on plasma interactions with large surfaces at high voltages

    NASA Technical Reports Server (NTRS)

    Grier, N. T.

    1980-01-01

    Multikilowatt power levels for future payloads can be more efficiently generated using solar arrays operating in the kilovolt range. This implies that large areas of the array at high operating voltages will be exposed to the space plasma environment. The resulting interactions of these high voltage surfaces with space plasma environments can seriously impact the performance of the satellite system. The plasma-surface interaction phenomena were studied in tests performed in two separate vacuum chambers, a 4.6 m diameter by 19.2 long chamber and a 20 m diameter by 27.4 m long chamber. The generated plasma density was approximately 1x10 to the 4th power/cu cm. Ten solar array panels, each with areas of 1400 sq cm were used in the tests. Nine of the solar panels were tested as a composite unit in the form of a 3x3 solar panel matrix. The results from all the tests confirmed small sample tests results: insulators were found to enhance the plasma coupling current for high positive bias and arcing was found to occur at high negative bias.

  16. Rheology of cross-linked polymers and polymer foams: Theory and experimental results

    NASA Astrophysics Data System (ADS)

    Herman, John N.

    Typical polymers have a time-dependent response to loading which results in stress relaxation or creep. Models using springs/dashpots or Volterra integrals are capable of predicting the material response, but place little or no emphasis on the reasoning behind the response. This research proposes a microscopic reasoning behind polymer chain movement, while developing a model to predict the creep and stress relaxation of a polymer foam. Based on the theorized slip/stick of polymer chains as they slide past each other, this model successfully predicts the behavior of a PMI polymer foam under tensile loads. This model lends insights into polymer microscopic behavior, which may be used for the development of future polymer materials. When possible, industry standard test methods are used to obtain tensile creep and stress relaxation results from rectangular specimens of Rohacell 31 IG foam. A common set of material parameters is fitted to the data, validating the micromechanic reasoning to polymer chain movement. To gain insight into observed test result variability, an investigation of the elastic modulus and material density relationship is performed using nominal foam densities of 31 kg/m3, 51 kg/m3,, 71 kg/m3. Additional testing and modeling is performed to validate the model under load/partial-unload/ hold, load/unload/recovery, and load/instantaneous-unload test cycles. The model successfully captures the observed material nuances during these more complex loading cycles.

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

    SciTech Connect

    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

    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.

  18. Analysis, design, and experimental results for lightweight space heat receiver canisters, phase 1

    NASA Technical Reports Server (NTRS)

    Schneider, Michael G.; Brege, Mark A.; Heidenreich, Gary R.

    1991-01-01

    Critical technology experiments have been performed on thermal energy storage modules in support of the Brayton Advanced Heat Receiver program. The modules are wedge-shaped canisters designed to minimize the mechanical stresses that occur during the phase change of the lithium fluoride phase change material. Nickel foam inserts were used in some of the canisters to provide thermal conductivity enhancement and to distribute the void volume. Two canisters, one with a nickel foam insert, and one without, were thermally cycled in various orientations in a fluidized bed furnace. The only measurable impact of the nickel foam was seen when the back and short sides of the canister were insulated to simulate operation in the advanced receiver design. In tests with insulation, the furnace to back side delta T was larger in the canister with the nickel foam insert, probably due to the radiant absorptivity of the nickel. However, the differences in the temperature profiles of the two canisters were small, and in many cases the profiles matched fairly well. Computed Tomography (CT) was successfully used to nondestructively demarcate void locations in the canisters. Finally, canister dimensional stability, which was measured throughout the thermal cycling test program with an inspection fixture was satisfactory with a maximum change of 0.635 mm (0.025 in.).

  19. Active Monitoring With The Use Of Seismic Vibrators: Experimental Systems And The Results Of Works

    NASA Astrophysics Data System (ADS)

    Kovalevsky, V.; Alekseev, A.; Glinsky, B.; Khairetdinov, M.; Seleznev, V.; Emanov, A.; Soloviev, V.

    2004-12-01

    Active methods of geophysical monitoring with the use of powerful seismic vibrators play an important role in the investigation of changes in the medium's stressed-deformed state in seismic prone zones for problems of seismic hazard prediction. In the last three decades, this scientific direction has been actively developed at institutes of Siberian Branch of Russian Academy of Sciences. In this period, experimental systems for the active monitoring of the medium, which include powerful vibrational sources with computer control systems, mobile specialized complexes for the precision recording of vibrational seismic signals, and data processing systems have been created. A review of various constructions of resonant vibrational seismic sources with a vibrational force of 100 tons in the frequency range from 5 to 15 Hz and the principles of creation of precision computer control systems and low-frequency three-component recording systems VIRS-M, VIRS-K, and ROSA is presented. A method for the active monitoring of the medium with the use of wideband sweep signals and narrow-band harmonic signals radiated by seismic vibrators has been developed. To determine the sensitivity of the active monitoring system, some experiments to detect the influence of the Earth's crust tidal deformations (of the order of 10-7) on seismic wave velocities have been performed. A 100-ton seismic vibrator and recording systems were located at a distance of 356 km. The radiation sessions of harmonic and sweep signals were repeated every 3 hours during 8 days. This made it possible to construct the time series of variations in the amplitudes and phases of the signals and wave arrival times. Both 12-hour and 24-hour periodicities correlated with the earth's tides were distinguished in the spectrum of variations of the recorded signals. The experiment has shown that the active monitoring system makes it possible to detect relative variations of the seismic wave velocities of the order of 10-5 - 10-6 in an area of 300-400 km around the source. This makes possible the direct monitoring of the state of stresses in an area of 100 thousand km2 to detect the regions and phases of the critical stress as an earthquake precursor. In recent years, works on the use of the method of vibroseismic interferometry for the active monitoring of the lake Baikal region have been started. The method is based on the seismic sounding of the region by powerful seismic vibrators with a long radiation of narrow-band harmonic signals. The changes in the stressed-deformed state are determined through the variations of the amplitude-phase characteristics of stationary wave fields, which are excited in the medium due to a long-time radiation of harmonic signals of constant frequency from the vibrator. The method of vibroseismic interferometry has a high sensitivity to the time changes of the parameters of the medium in the case of long-distance observations. A peculiarity of the experiments is the simultaneous use of the data of regional seismic stations and mobile recording complexes.

  20. Influence of Protolith Composition and Sliding Velocity on the Microfabric of Fault Gouge: Experimental Results

    NASA Astrophysics Data System (ADS)

    Song, C.; Underwood, M.; Schleicher, A.; Ikari, M.; Saffer, D. M.; Marone, C.

    2013-12-01

    The relation between fault gouge fabric and fault-slip behavior remains a central unknown in our knowledge of fault and earthquake mechanics. The linkage of cause to effect remains cryptic in part because natural gouges are highly variable (i.e., particle size distribution, mineralogy, microfabric), due to the heterogeneity of protoliths and differences in cumulative slip. To help isolate key variables, we conducted a series of direct shearing tests in a double direct shear configuration, on specimens of artificial powdered gouge. The experiments were conducted under room temperature and humidity conditions (RH = 14.4-32.8%), using ~3 mm-thick (prior to shearing) layers with nominal contact areas of 5x5 cm. Layers were sheared between grooved steel forcing blocks designed to minimize slip at the layer boundary. We tested four gouge compositions: illitic shale, chlorite schist, a 50:50 mixture of smectite and quartz, and Westerly granite. Three load point sliding velocities were applied (1.15, 11.5, and 115 microns/sec), and all experiments were conducted under a normal stress of ~50 MPa. As expected, the coefficients of friction vary as a function of both composition and sliding velocity. The smectite:quartz mixture is consistently weakest (0.38-0.39) and granite gouge is consistently strongest (0.60-0.61). Gouges of illitic shale and chlorite schist yielded larger differences as a function of sliding velocity, 0.40-0.53 and 0.48-0.58, respectively. To characterize the microfabric that developed within each sample during shearing, the twelve experimental wafers were analyzed by X-ray texture goniometry (XTG) and imaged (uncoated) using an FEI Quanta 600 scanning electron microscopy in low vacuum mode (80 Pa). SEM images were shot parallel and perpendicular to the shear plane at high voltage (30 kV) with spot size of 3.0 and working distance of 10 mm. After processing the digital images (1000X magnification), we ran statistical analyses of the apparent long-axis orientations, with an average of 660 grains per view (i.e., graphical standard deviation of the azimuths). Preferred orientations are much stronger on views perpendicular to the shear plane, whereas grains on shear-parallel surfaces are randomly oriented. Within each gouge composition, samples subjected to faster sliding velocity developed more highly preferred grain orientations. Among the four compositions, both SEM and XTG show that chlorite schist gouge developed the most highly preferred orientation, granite and smectite:quartz the least. Faster sliding velocity weakens the fabric of chlorite-rich gouge but strengthens the fabric of illite-rich gouge. Although the alignment of microfabric in natural fault gouge is undoubtedly enhanced by repeated slip events and growth of diagenetic phases, our experiments show that protolith mineralogy, especially the abundance and types of phyllosilicates, is a key prerequisite to preferred grain orientation and fabric development.

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

    NASA Technical Reports Server (NTRS)

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

    1981-01-01

    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.

  2. Experimental demonstration of high two-photon time-energy entanglement

    SciTech Connect

    Ali Khan, Irfan; Howell, John C.

    2006-03-15

    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.

  3. Experimental Results of Plasma Induced EMI Effects in a Reflector Antenna System

    NASA Astrophysics Data System (ADS)

    Bandinelli, M.; Pandolfo, L.; Sarri, A.; Fittipaldi, D. A.; Pawlak, H.; Marliani, F.

    2012-05-01

    This paper presents measurement results of the electromagnetic interference (EMI) caused by the plasma plume of ion thrusters firing through the RF beam of reflector antennas. The EMI effect consists mainly in the introduction of discrete spurious modulation products on the RF carrier thus degrading spectral purity. The measurements were carried out on a mockup which is geometrically representative of the actual SGEO spacecraft design. The mockup and the acquisition system were specifically designed to allow RF measurements inside a metallic vacuum chamber. Three ion thrusters were characterised during the test campaign: SPT-100, HEMP-T, PPS-1350.

  4. Scattering cross sections of liquid deuterium for ultracold neutrons: Experimental results and a calculation model

    E-print Network

    Döge, Stefan; Müller, Stefan; Morkel, Christoph; Gutsmiedl, Erwin; Geltenbort, Peter; Lauer, Thorsten; Fierlinger, Peter; Petry, Winfried; Böni, Peter

    2015-01-01

    We present scattering cross sections $\\sigma_\\text{scatt}$ of ultracold neutrons (UCN) in liquid deuterium at T = 20.6 K, as recently measured by means of a transmission experiment. The indispensable thorough raw data treatment procedure is explained. A calculation model for coherent and incoherent scattering in liquid deuterium in the hydrodynamic limit based on appropriate physical concepts is provided and shown to ?t the data well. The applicability of the incoherent approximation for UCN scattering in liquid deuterium was tested and found to deliver acceptable results.

  5. Preliminary Results of an Experimental Investigation of the Qu Superconducting Heat Pipe

    NASA Technical Reports Server (NTRS)

    Blackmon, James B.; Entrekin, Sean F.

    2006-01-01

    This note on preliminary results of our evaluation of the so-called Qu Tube is prompted in part by recent concerns expressed to the authors by some researchers regarding the performance characteristics of the superconducting, solid-state heat pipe as described in the patents, or on the company's websites. Briefly, the company's claims include: a new type of heat transfer mechanism that is a form of solid state thermal superconductivity, which results in an effective thermal conductivity of the order of tens of thousands of times that of an equivalent solid silver bar, or, tens to hundreds of times that of liquid - vapor heat pipes. The company's website also refers to tests conducted by Stanford Research Institute that substantiate these claims, but the report is apparently not publicly available. We are conducting an investigation of the Qu Tube under a NASA Grant, and in general find that these claims have merit, but our study is not yet complete. We present some of our preliminary results in part to show that it would not be imprudent to conduct such studies, especially for possible future applications requiring exceptional thermal management performance capabilities. Working with HiTek Services, we originally acquired several Qu Tubes, including 17" long, 5/16" diameter copper tubes, one that is 7 7/8" long, 3/16" diameter, and one that is 4" long, 1" diameter. We subjected the smaller tubes to various exploratory tests, including a transient test with electrical band heaters, boiling water tests, and a series of steady state tests with electrical band heaters heating one end with free convective cooling along the remainder of the length. All results indicate a very high thermal conductivity, but the length of these tubes limited our ability to obtain accurate data on temperature gradients, necessary to determine the effective thermal conductivity. We then acquired nine Qu Tubes that are 10' long, 5/16" diameter, and we have recently conducted initial tests, which further support the claims of exceptional thermal conductivity.

  6. A system identification technique based on the random decrement signatures. Part 2: Experimental results

    NASA Technical Reports Server (NTRS)

    Bedewi, Nabih E.; Yang, Jackson C. S.

    1987-01-01

    Identification of the system parameters of a randomly excited structure may be treated using a variety of statistical techniques. Of all these techniques, the Random Decrement is unique in that it provides the homogeneous component of the system response. Using this quality, a system identification technique was developed based on a least-squares fit of the signatures to estimate the mass, damping, and stiffness matrices of a linear randomly excited system. The results of an experiment conducted on an offshore platform scale model to verify the validity of the technique and to demonstrate its application in damage detection are presented.

  7. Chemical vapor deposition of solid oxides in porous media for ceramic membrane preparation. Comparison of experimental results with semianalytical solutions

    SciTech Connect

    Xomeritakis, G.; Lin, Y.S. . Dept. of Chemical Engineering)

    1994-11-01

    Explicit equations correlating chemical vapor deposition (CVD) conditions and substrate parameters to the deposition zone thickness, location of maximum deposition, and pore size evolution of a modified counterdiffusion CVD process (MCVD) are derived from recently developed semianalytical solutions. The permeability reduction ratio and the substrate average pore size as a function of deposition time are calculated using the semianalytical solutions and substrate pore size distribution data. Recently reported experimental data of CVD of ZrO[sub 2], TiO[sub 2], and Al[sub 2]O[sub 3] in porous substrates are compared with the theoretical results in terms of the location of maximum deposition, deposition zone thickness, permeability reduction ratio, change in average pore size, and pore closure time. The theoretical results agree reasonably well with the experimental findings and provide an improved insight into the MCVD process for ceramic membrane fabrication.

  8. Mathematical Model and Experimental Results for Cryogenic Densification and Sub-Cooling Using a Submerged Cooling Source

    NASA Technical Reports Server (NTRS)

    Partridge, J. K.; Notardonato, W. U.; Johnson, W. L.; Tuttle, J. W.

    2011-01-01

    Among the many factors that determine overall rocket performance, propellant density is important because it affects the size of the rocket. Thus, in order to decrease the size of a rocket, it may be desirable to increase the density of propellants. This study analyzes the concept of increasing the propellant density by employing a cooling source submerged in the liquid propellant. A simple, mathematical model was developed to predict the rate of densification and the propellant temperature profile. The mathematical model is generic and applicable to multiple propellants. The densification rate was determined experimentally by submerging a cooling source in liquid oxygen at constant, positive pressure, and measuring the time rate of change in temperature with respect to vertical position. The results from the mathematical model provided a reasonable fit when compared to experimental results.

  9. The HIT-II Spherical Torus: Physics and Key Experimental Results

    NASA Astrophysics Data System (ADS)

    Redd, A. J.; Hamp, W. T.; Izzo, V. A.; Jarboe, T. R.; Nelson, B. A.; O'Neill, R. G.; Raman, R.; Sieck, P. E.; Smith, R. J.

    2004-11-01

    Discharges in the HIT-II spherical torus device [Redd et al., Phys. Plasmas 9, 2006 (2002)] can be driven by either Ohmic or Coaxial Helicity Injection (CHI) current drive. A new CHI operating regime has been explored, with toroidal plasma currents of up to 350 kA, I_p/I_TF ratios of up to 1.2, and internal probing data which may demonstrate the formation of a closed-flux core. The key to acheiving these results is the magnetic field shear in the CHI injector region, with a minimum shear necessary for current build-up. Ohmic plasma performance has also improved, with peak currents up to 300 kA, with and without transient CHI startup. The CHI startup technique [Raman et al., Phys. Plasmas 11, 2565 (2004)] provides more robust discharges, with a wider operating space and more efficient use of the transformer Volt-seconds, than unassisted Ohmic. Finally, CHI can be used to enhance an Ohmic plasma current without significantly degrading the quality of the discharge. Results will be presented for each HIT--II operating regime, including empirical performance scalings and applicable parametric operating spaces.

  10. Experimental Results on the Feasibility of an Aerospike for Hypersonic Missiles

    NASA Technical Reports Server (NTRS)

    Huebner, Lawrence D.; Mitchell, Anthony M.; Boudreaux, Ellis J.

    1995-01-01

    A series of wind tunnel tests have been performed on an aerospike-protected missile dome at a Mach number of 6 to obtain quantitative surface pressure and temperature-rise data, as well as qualitative flow visualization data. These data were used to determine aerospike concept feasibility and will also provide a database to be used for calibration of computational fluid dynamics codes. Data were obtained on the hemispherical missile dome with and without an aerospike that protrudes ahead of the dome along the axisymmetric center line. Data were obtained on two models (one pressure, one temperature) in the NASA Langley 20-Inch Mach 6 Tunnel at a freestream Reynolds number of 8.0 x 10(exp 6) per feet and angles of attack from 0 to 40 degrees. Surface pressure and temperature-rise results indicate that the aerospike is effective for very low angles of attack (less than 5 degrees) at Mach 6. Above 5 degrees, impingement of the aerospike bow shock and the flow separation shock from the recirculation region created by the aerospike causes pressure and temperature increases on the windward side of the dome which exceed values observed in the same region with the aerospike removed. Flow characterization obtained via oil-flow and schlieren photographs provides some insight into the quantitative surface data results, including vortical flow and shock-wave impingement.

  11. Pulsed thermographic inspection of CFRP structures: experimental results and image analysis tools

    NASA Astrophysics Data System (ADS)

    Theodorakeas, P.; Avdelidis, N. P.; Ibarra-Castanedo, C.; Koui, M.; Maldague, X.

    2014-03-01

    In this study, three different CFRP specimens with internal artificial delaminations of various sizes and located at different depths were investigated by means of Pulsed Thermography (PT) under laboratory conditions. The three CFRP panels, having the same thickness and defects characteristics but with a different shape (planar, trapezoid and curved), were assessed after applying various signal processing tools on the acquired thermal data (i.e. Thermographic Signal Reconstruction, Pulsed Phase Thermography and Principal Component Thermography). The effectiveness of the above processing tools was initially evaluated in a qualitative manner, comparing the imaging outputs and the information retrieval in terms of defect detectability enhancement and noise reduction. Simultaneously, the produced defect detectability was evaluated through Signal-to-Noise Ratio (SNR) computations, quantifying the image quality and the intensity contrast produced between the defected area and the adjacent background area of the test panel. From the results of this study, it can be concluded that the implementation of PT along with the application of advanced signal processing algorithms can be a useful technique for NDT assessment, providing enhanced qualitative information. Nevertheless, SNR analysis showed that despite the enhanced visibility resulting from these algorithms, these can be properly applied in order to retrieve the best possible information according to the user's demands.

  12. The effects of pneumoperitoneum and controlled ventilation on peritoneal lymphatic bacterial clearance: experimental results in rats

    PubMed Central

    Casaroli, Armando Angelo; Mimica, Lycia M. J.; Fontes, Belchor; Rasslan, Samir

    2011-01-01

    OBJECTIVE: To evaluate the effect of pneumoperitoneum, both alone and in combination with controlled ventilation, on peritoneal lymphatic bacterial clearance using a rat bacterial peritonitis model. METHOD: A total of 69 male Wistar rats were intraperitoneally inoculated with an Escherichia coli solution (109 colony-forming units (cfu)/mL) and divided into three groups of 23 animals each: A (control group), B (pneumoperitoneum under 5 mmHg of constant pressure), and C (endotracheal intubation, controlled ventilation, and pneumoperitoneum as in Group B). The animals were sacrificed after 30 min under these conditions, and blood, mediastinal ganglia, lungs, peritoneum, liver, and spleen cultures were performed. RESULTS: Statistical analyses comparing the number of cfu/sample in each of the cultures showed that no differences existed between the three groups. CONCLUSION: Based on our results, we concluded that pneumoperitoneum, either alone or in association with mechanical ventilation, did not modify the bacterial clearance through the diaphragmatic lymphatic system of the peritoneal cavity. PMID:22179170

  13. Dynamic performance of packed-bed dehumidifiers: experimental results from the SERI desiccant test loop

    SciTech Connect

    Kutscher, C F; Barlow, R S

    1982-08-01

    Discussed are the design and construction of a desiccant test loop and results of tests with a silica-gel-packed bed. The test loop consists of two centrifugal fans, two duct heaters, a steam humidifier, 24.4m (80 ft) of 30-cm (12-in.) circular duct, instrumentation, and a test section. The loop is capable of testing adsorption and desorption modes at flow rates up to 0.340 kg/s (600 scfm) and at regeneration temperatures up to 120/sup 0/C (248/sup 0/F). Tests of a 74-cm(29-in.)-diameter, 3.2-cm(1.25-in.)-thick silica gel bed indicated that mass transfer occurs more readily in the adsorption direction than in the desorption direction. Pressure drop data indicated that the resistance of each of the two screens that hold the silica gel in place was equivalent to 2.5-cm(1-in.) of silica gel due to plugging. Results of the tests were also used to validate a SERI desiccant computer model, DESSIM.

  14. Effect of dactyloscopic powders on DNA profiling from enhanced fingerprints: results from an experimental study.

    PubMed

    Tozzo, Pamela; Giuliodori, Alice; Rodriguez, Daniele; Caenazzo, Luciana

    2014-03-01

    We conducted a study on the effect of fingerprint enhancement methods on subsequent short tandem repeat profiling. First, we performed a study typing blood traces deposited on 5 different surfaces, treated with 8 types of dactyloscopic powders. Three different DNA extraction methods were used. Subsequently, we analyzed latent fingerprints on the same 5 surfaces enhanced with the 8 different powders used in the first part of the study. This study has demonstrated that DNA profiling can be performed on fingerprints left on different substrates, and the substrate will affect the amount of DNA that can be recovered for DNA typing. In the first phase of the study, a profile was obtained in 92% of the 120 samples analyzed; in the second part, in 55% of the 80 samples analyzed, we obtained a profile complete in 32.5% of the cases. From the results obtained, it seems that the powders used in latent fingerprints enhancement, rather than having a direct inhibitory effect on extraction and amplification of DNA, may cause partial degradation of DNA, reducing the efficiency of amplification reaction. It should not be forgotten that these results were obtained under laboratory conditions, and in real caseworks, there may still be different problems involved. PMID:24457585

  15. On the influence of strain rate in acousto-elasticity : experimental results for Berea sandstone

    NASA Astrophysics Data System (ADS)

    Riviere, J. V.; Candela, T.; Scuderi, M.; Marone, C.; Guyer, R. A.; Johnson, P. A.

    2013-12-01

    Elastic nonlinear effects are pervasive in the Earth, including during strong ground motion, tidal forcing and earthquake slip processes. We study elastic nonlinear effects in the laboratory with the goal of developing new methods to probe elastic changes in the Earth, and to characterize and understand their origins. Here we report on nonlinear, frequency dispersion effects by applying a method termed dynamic acousto-elasticity (DAE), analogous to quasi-static acousto-elasticity. DAE allows one to obtain the elastic behavior over the entire dynamic cycle, detailing the full nonlinear behavior under tension and compression, including hysteresis and memory effects. We perform DAE on samples of Berea sandstone subject to 0.5 MPa uniaxial and biaxial loading conditions with oscillating loads at frequencies from 0.001 to 10 Hz and amplitudes of a few 100 kPa. We compare results to DAE measurements made in the kHz range. We observe that the average decrease in modulus due to nonlinear material softening increases with frequency, suggesting a frequency and/or a strain rate dependence. Previous quasi-static measurements (Claytor et al., GRL 2009) show that stress-strain nonlinear hysteretic behavior disappears when the experiment is performed at a very low strain-rate, implying that a rate dependent nonlinear elastic model would be useful (Gusev et al., PRB 2004). Our results also suggest that when elastic nonlinear Earth processes are studied, stress forcing frequency is an important consideration, and may lead to unexpected behaviors.

  16. Experimental rotordynamic coefficient results for teeth-on-rotor and teeth-on-stator labyrinth gas seals

    NASA Technical Reports Server (NTRS)

    Childs, Dara W.; Scharrer, Joseph K.

    1987-01-01

    An experimental test facility is used to measure the rotordynamic coefficients of teeth-on-rotor and teeth-on-stator labyrinth gas seals. Direct damping coefficients are presented for these seals for the first time. The results are presented for the two seal configurations at identical operating conditions, and show that, in a rotordynamic sense, the teeth-on-stator seal is more stable than the teeth-on-rotor seal, for inlet tangential velocity in the direction of rotation.

  17. Experimental rotordynamic coefficient results for teeth-on-rotor and teeth-on-stator labyrinth gas seals

    NASA Technical Reports Server (NTRS)

    Childs, D. W.; Scharrer, J. K.

    1986-01-01

    An experimental test facility is used to measure the rotordynamic coefficients of teeth-on-rotor and teeth-on-stator labyrinth gas seals. Direct damping coefficients are presented for these seals for the first time. The results are presented for the two seal configurations at identical operating conditions, and show that, in a rotordynamic sense, the teeth-on-stator seal is more stable than the teeth-on-rotor seal, for inlet tangential velocity in the direction of rotation.

  18. Sorption and retardation of strontium in saturated Chinese loess: experimental results and model analysis.

    PubMed

    Huo, Lijuan; Qian, Tianwei; Hao, Junting; Zhao, Dongye

    2013-02-01

    Geological burial and landfill have been widely practiced for disposal of nuclear wastes. However, radionuclides in the waste leachate from landfill facilities can contaminate soil and groundwater. Chinese loess is widely distributed in China and has been involved in large-scale disposal of nuclear wastes. Consequently, there has been an urgent need for understanding and predicting the fate and transport of contaminants in both vadose and saturated zones in the loess. In this paper, the distribution coefficient (K(d)) values of Strontium between a Chinese loess and groundwater were determined in batch experiments. The isotherm could be described with nearly linear isotherm model, which resulted in a K(d) value of 40.0 cm(3)/g. Based on this K(d) value, the retardation factor (R(d), the ratio of pore water velocity to solute transport velocity) value was calculated to be 112.6. As an alternative approach, the R(d) value was also determined through independent column experiments and transport modeling. Bromide (Br(-)) was used as a non-reactive tracer, and reagent SrCl(2) was used as a surrogate for the radioactive isotope ((99)Sr) in the experiment because they share the same adsorption and transportation characteristics. An equilibrium-based model and a two-region non-equilibrium model were employed to interpret the column sorption data of Sr. The computer program, CXTFIT 2.1, was used to estimate the parameters by simulating the breakthrough and retention curves of Br and Sr, respectively. The resultant D (dispersion coefficient) value for Sr transport was much lower than that of Br(-), indicating the important effect of chemical non-equilibrium of Sr in the loess system. The observed Sr retention curves in the loess were best modeled by the two-site transport model. The R(d) value determined from batch equilibrium tests differed markedly from that determined from the column transport experiments, and the R(d) value decreased with increasing pore-water velocity. The relationship between D and pore water flow velocity (v) was determined as a D = 1.192v(1.26). The results from this work indicate that the strong flow and non-equilibrium effects on the transport parameters (R(d) and D) must be taken into account in Sr transport modeling. PMID:23085342

  19. Erythrocyte Concentrates Recovered from Under-Collected Whole Blood: Experimental and Clinical Results

    PubMed Central

    Zhang, Jing-Jing; Wu, Min-Hui; Liu, Yan-Chun; Cai, Li; Li, Zheng-Gang; Huang, Bing; Wei, Peng; Sun, Jun; Zhu, Yi

    2015-01-01

    Background Although periodic blood shortages are widespread in major Chinese cities, approximately 1x105 U of whole blood are discarded yearly because of under-collection. To reduce the wastage of acid citrate dextrose solution B (ACD-B) anticoagulated under-collected whole blood (UC-WB), this study was performed to elucidate the effect of extracellular pH and holding time on erythrocyte quality. Mannitol-adenine-phosphate (MAP) erythrocyte concentrates (UC-RBCs) were prepared with UC-WB to assess the safety and efficacy of this component. Methods The effect of the different extracellular pH levels and storage times on erythrocytes was assessed by fluorescent probes, SDS-PAGE electrophoresis, electron microscopy and spectroscopy. In vitro properties of 34 UC-RBCs that were prepared with UC-WB at different times after collection were analyzed and compared to normal RBCs during 35 days of storage. The results of transfusion with UC-RBCs and the incidence of adverse reactions in 49 patients were determined. Results 1) Low extracellular pH levels and long storage time induced increases in RBC fluorescence polarization and mean microviscosity, changes in membrane fluidity, band 1, 2 and 3 protein expression, and erythrocyte morphology. 2) During storage for 35 days, difference in between-subjects effects of K+, hemolysis and supernatant erythrocyte membrane protein (EMP) were statistically significant (P = 0.041, 0.007 and 0.002, respectively), while the differences between these parameters in the 4 h group and comparable controls were less significant. 3) Clinical data from 49 patients confirmed that transfusions with UC-RBCs were satisfactory with no adverse reactions. Conclusion These results suggest that it is feasible to prepare RBCs with ACD-B anticoagulated UC-WB at a minimum of 66% volume of the labeled collection. It was effective and safe to transfuse the UC-RBCs prepared within 4 h after collection and stored within 7 days. The use of UC-WB would be a welcome addition to limited blood resources in China. Trial Registration Chinese Clinical Trial Registry ChiCTR-TRC-13003967 PMID:25706725

  20. Experimental and simulation study results for video landmark acquisition and tracking technology

    NASA Technical Reports Server (NTRS)

    Schappell, R. T.; Tietz, J. C.; Thomas, H. M.; Lowrie, J. W.

    1979-01-01

    A synopsis of related Earth observation technology is provided and includes surface-feature tracking, generic feature classification and landmark identification, and navigation by multicolor correlation. With the advent of the Space Shuttle era, the NASA role takes on new significance in that one can now conceive of dedicated Earth resources missions. Space Shuttle also provides a unique test bed for evaluating advanced sensor technology like that described in this report. As a result of this type of rationale, the FILE OSTA-1 Shuttle experiment, which grew out of the Video Landmark Acquisition and Tracking (VILAT) activity, was developed and is described in this report along with the relevant tradeoffs. In addition, a synopsis of FILE computer simulation activity is included. This synopsis relates to future required capabilities such as landmark registration, reacquisition, and tracking.

  1. Condensation-Evacuated Cryogenic Thermal Insulation Systems: Experimental Results of Effects of Deposited Filling Gases

    NASA Astrophysics Data System (ADS)

    Geisler, M.; Wachtel, J.; Hoffmann, J.; Ebert, H.-P.

    2010-04-01

    The objective of this work is to investigate the effect of deposited CO2 on the solid thermal conductivity of evacuated cryogenic insulation systems. Therefore, measurements were performed using a modified guarded hot-plate (GHP) apparatus with bellows, acting as sample containment at temperatures in the range from 77 K to 300 K. These gas tight bellows allows the venting of the specimen with a defined gas volume. Existing thermal heat transfer models, which assume a superposition of thermal transfer due to radiation and solid thermal conductivity, were used to account for the thermal effects of deposited gases and the resulting increase of the solid thermal conductivity. Measurements were performed on typical insulation material classes, e.g. powders, fibres and foams.

  2. Participation of Bell Telephone Laboratories in Project Echo and Experimental Results

    NASA Technical Reports Server (NTRS)

    Jakes, William C., Jr.

    1961-01-01

    On August 12, 1960, Echo I, a 100-foot-diameter spherical balloon, was placed in orbit around the earth by the National Aeronautics and Space Administration. The objective was to demonstrate the feasibility of long-distance communication by microwave reflection from a satellite. A two-way coast-to-coast voice circuit was to be established between the Jet Propulsion Laboratory (JPL) facility in California and a station provided by Bell Telephone Laboratories (STL) in New Jersey. Similar tests were also planned with the Naval Research Laboratory and other stations. This paper describes the general organization and operation of the Holmdel, New Jersey, station, and discusses the results of the experiments performed between the balloon launching and March 1, 1961. Successful voice communication was achieved through a variety of modulation methods including frequency modulation with feedback, amplitude modulation, single-sideband modulation, and narrow-band phase modulation. Careful measurements were also made of the loss in the transmission path.

  3. Comparison of experimental and computational results for reverse ballistic tests into foundry core

    SciTech Connect

    Yarrington, P.; Norwood, F. R.; Grady, D. E.

    1980-03-01

    A series of nine laboratory-scale penetration tests was conducted in which impact velocity and geometry of the projectile were varied. In all tests, displacement histories were obtained for the penetrator via displacement interferometric techniques. From the data, accelerations were deduced and compared with numerically-calculated accelerations. For the numerical work, the codes PENAP and WONDY were used to model the penetration events. For penetrators with a conical nose, agreement between calculated and measured accelerations could be brought within 15% for all tests, except for one PENAP/test comparison, by introducing a constant coefficient of Coulomb friction of 0.1 at the penetration target interface. For penetrators with an ogival nose, on the other hand, a greater discrepancy was found between calculated and measured results.

  4. Comparison of ISRU Excavation System Model Blade Force Methodology and Experimental Results

    NASA Technical Reports Server (NTRS)

    Gallo, Christopher A.; Wilkinson, R. Allen; Mueller, Robert P.; Schuler, Jason M.; Nick, Andrew J.

    2010-01-01

    An Excavation System Model has been written to simulate the collection and transportation of regolith on the Moon. The calculations in this model include an estimation of the forces on the digging tool as a result of excavation into the regolith. Verification testing has been performed and the forces recorded from this testing were compared to the calculated theoretical data. A prototype lunar vehicle built at the NASA Johnson Space Center (JSC) was tested with a bulldozer type blade developed at the NASA Kennedy Space Center (KSC) attached to the front. This is the initial correlation of actual field test data to the blade forces calculated by the Excavation System Model and the test data followed similar trends with the predicted values. This testing occurred in soils developed at the NASA Glenn Research Center (GRC) which are a mixture of different types of sands and whose soil properties have been well characterized. Three separate analytical models are compared to the test data.

  5. Experimental Aerodynamic Characteristics of the Pegasus Air-Launched Booster and Comparisons with Predicted and Flight Results

    NASA Technical Reports Server (NTRS)

    Rhode, M. N.; Engelund, Walter C.; Mendenhall, Michael R.

    1995-01-01

    Experimental longitudinal and lateral-directional aerodynamic characteristics were obtained for the Pegasus and Pegasus XL configurations over a Mach number range from 1.6 to 6 and angles of attack from -4 to +24 degrees. Angle of sideslip was varied from -6 to +6 degrees, and control surfaces were deflected to obtain elevon, aileron, and rudder effectiveness. Experimental data for the Pegasus configuration are compared with engineering code predictions performed by Nielsen Engineering & Research, Inc. (NEAR) in the aerodynamic design of the Pegasus vehicle, and with results from the Aerodynamic Preliminary Analysis System (APAS) code. Comparisons of experimental results are also made with longitudinal flight data from Flight #2 of the Pegasus vehicle. Results show that the longitudinal aerodynamic characteristics of the Pegasus and Pegasus XL configurations are similar, having the same lift-curve slope and drag levels across the Mach number range. Both configurations are longitudinally stable, with stability decreasing towards neutral levels as Mach number increases. Directional stability is negative at moderate to high angles of attack due to separated flow over the vertical tail. Dihedral effect is positive for both configurations, but is reduced 30-50 percent for the Pegasus XL configuration because of the horizontal tail anhedral. Predicted longitudinal characteristics and both longitudinal and lateral-directional control effectiveness are generally in good agreement with experiment. Due to the complex leeside flowfield, lateral-directional characteristics are not as well predicted by the engineering codes. Experiment and flight data are in good agreement across the Mach number range.

  6. A new MIG-3 gyrotron complex for creation and heating of plasma in the L-2M stellarator and the first experimental results

    NASA Astrophysics Data System (ADS)

    Batanov, G. M.; Belousov, V. I.; Bondar', Yu. F.; Borzosekov, V. D.; Vasil'kov, D. G.; Grebenshchikov, S. E.; Ivannikov, I. A.; Kolik, L. V.; Konchekov, E. M.; Malakhov, D. V.; Matveev, N. V.; Meshcheryakov, A. I.; Petrov, A. E.; Sarksyan, K. A.; Skvortsova, N. N.; Stepakhin, V. D.; Kharchev, N. K.; Khol'nov, Yu. V.; Tai, E. M.

    2013-12-01

    The characteristics of a new MIG-3 gyrotron complex for creating and heating plasma in the L-2M stellarator are presented. The first experimental results using the complex are reported. The complex consists of two three-electrode GYCOM gyrotrons of the new generation with electron beam energy recuperation, a high-voltage modulator that enables both separate and simultaneous operation of the two gyrotrons, and a control/data-recording unit. The total specific power to be inserted into plasma reaches 5 MW/m3 when both gyrotrons in operation.

  7. A comparison of experimental and theoretical results for leakage, pressure distribution, and rotordynamic coefficients for annular gas seals

    NASA Technical Reports Server (NTRS)

    Nicks, C. O.; Childs, D. W.

    1984-01-01

    The importance of seal behavior in rotordynamics is discussed and current annular seal theory is reviewed. A Nelson's analytical-computational method for determining rotordynamic coefficients for this type of compressible-flow seal is outlined. Various means for the experimental identification of the dynamic coefficients are given, and the method employed at the Texas A and M University (TAMU) test facility is explained. The TAMU test apparatus is described, and the test procedures are discussed. Experimental results, including leakage, entrance-loss coefficients, pressure distributions, and rotordynamic coefficients for a smooth and a honeycomb constant-clearance seal are presented and compared to theoretical results from Nelson's analysis. The results for both seals show little sensitivity to the running speed over the test range. Agreement between test results and theory for leakage through the seal is satisfactory. Test results for direct stiffness show a greater sensitivity to fluid pre-rotation than predicted. Results also indicate that the deliberately roughened surface of the honeycomb seal provides improved stability versus the smooth seal.

  8. Inviscid Flow Field Effects: Experimental results. [optical distortions over airborne laser turrets

    NASA Technical Reports Server (NTRS)

    Otten, L. J., III; Gilbert, K. G.

    1980-01-01

    The aero-optical distortions due to invisid flow effects over airborne laser turrets is investigated. Optical path differences across laser turret apertures are estimated from two data sources. The first is a theoretical study of main flow effects for a spherical turret assembly for a Mach number (M) of 0.6. The second source is an actual wind tunnel density field measurement on a 0.3 scale laser turret/fairing assembly, with M = 0.75. A range of azimuthal angles from 0 to 90 deg was considered, while the elevation angle was always 0 deg (i.e., in the plane of the flow). The calculated optical path differences for these two markedly different geometries are of the same order. Scaling of results to sea level conditions and an aperture diameter of 50 cm indicated up to 0.0007 cm of phase variation across the aperture for certain forward look angles and a focal length of F = -11.1 km. These values are second order for a 10.6 micron system.

  9. Experimental results of single screw mechanical tests: a follow-up to SAND2005-6036.

    SciTech Connect

    Lee, Sandwook; Lee, Kenneth L.; Korellis, John S.; McFadden, Sam X.

    2006-08-01

    The work reported here was conducted to address issues raised regarding mechanical testing of attachment screws described in SAND2005-6036, as well as to increase the understanding of screw behavior through additional testing. Efforts were made to evaluate fixture modifications and address issues of interest, including: fabrication of 45{sup o} test fixtures, measurement of the frictional load from the angled fixture guide, employment of electromechanical displacement transducers, development of a single-shear test, and study the affect of thread start orientation on single-shear behavior. A286 and 302HQ, No.10-32 socket-head cap screws were tested having orientations with respect to the primary loading axis of 0{sup 0}, 45{sup o}, 60{sup o}, 75{sup o} and 90{sup o} at stroke speeds 0,001 and 10 in/sec. The frictional load resulting from the angled screw fixture guide was insignificant. Load-displacement curves of A286 screws did not show a minimum value in displacement to failure (DTF) for 60{sup o} shear tests. Tests of 302HQ screws did not produce a consistent trend in DTF with load angle. The effect of displacement rate on DTF became larger as shear angle increased for both A286 and 302HQ screws.

  10. Experimental Results of Performance Tests on a Four-Port Wave Rotor

    NASA Technical Reports Server (NTRS)

    Wilson, John; Welch, Gerard E.; Paxson, Daniel E.

    2007-01-01

    A series of tests has been performed on a four-port wave rotor suitable for use as a topping stage on a gas turbine engine, to measure the overall pressure ratio obtainable as a function of temperature ratio, inlet mass flow, loop flow ratio, and rotor speed. The wave rotor employed an open high pressure loop that is the high pressure inlet flow was not the air exhausted from the high pressure outlet, but was obtained from a separate heated source, although the mass flow rates of the two flows were balanced. This permitted the choice of a range of loop-flow ratios (i.e., ratio of high pressure flow to low pressure flow), as well as the possibility of examining the effect of mass flow imbalance. Imbalance could occur as a result of leakage or deliberate bleeding for cooling air. Measurements of the pressure drop in the high pressure loop were also obtained. A pressure ratio of 1.17 was obtained at a temperature ratio of 2.0, with an inlet mass flow of 0.6 lb/s. Earlier tests had given a pressure ratio of less than 1.12. The improvement was due to improved sealing between the high pressure and low pressure loops, and a modification to the movable end-wall which is provided to allow for rotor expansion.

  11. An Experimental Evaluation of HVAC-Grade Carbon-Dioxide Sensors: Part 2, Performance Test Results

    SciTech Connect

    Shrestha, Som S; Maxwell, Dr. Gregory

    2010-01-01

    This is the second paper in a four-part series reporting on the test and evaluation of typical carbon-dioxide sensors used in building HVAC applications. Fifteen models of NDIR HVAC-grade CO2 sensors were tested and evaluated to determine the accuracy, linearity, repeatability, and hysteresis of each sensor. This paper describes the performance of the sensors and provides a comparison with the manufacturers specifications. The sensors were tested at 40% relative humidity, 73oF (22.8oC) temperature, 14.70 psia (101.35 kPa) pressure, and at five different CO2 concentrations (400 ppm, 750 ppm, 1100 ppm, 1450 ppm, and 1800 ppm). The test results showed a wide variation in sensor performance among the various manufacturers and in some cases a wide variation among sensors of the same model. In all, 45 sensors were evaluated: three from each of the 15 models. Among the 15 models tested, eight models have a single-lamp, single-wavelength configuration, four models have a dual-lamp, single-wavelength configuration, and three models have a single-lamp, dual-wavelength configuration.

  12. Carbon sequestration via reaction with basaltic rocks: geochemical modeling and experimental results

    USGS Publications Warehouse

    Rosenbauer, Robert J.; Thomas, Burt; Bischoff, James L.; Palandri, James

    2012-01-01

    Basaltic rocks are potential repositories for sequestering carbon dioxide (CO2) because of their capacity for trapping CO2 in carbonate minerals. We carried out a series of thermodynamic equilibrium models and high pressure experiments, reacting basalt with CO2-charged fluids over a range of conditions from 50 to 200 °C at 300 bar. Results indicate basalt has a high reactivity to CO2 acidified brine. Carbon dioxide is taken up from solution at all temperatures from 50 to 200 °C, 300 bar, but the maximum extent and rate of reaction occurs at 100 °C, 300 bar. Reaction path simulations utilizing the geochemical modeling program CHILLER predicted an equilibrium carbonate alteration assemblage of calcite, magnesite, and siderite, but the only secondary carbonate identified in the experiments was a ferroan magnesite. The amount of uptake at 100 °C, 300 bar ranged from 8% by weight for a typical tholeite to 26% for a picrite. The actual amount of CO2 uptake and extent of rock alteration coincides directly with the magnesium content of the rock suggesting that overall reaction extent is controlled by bulk basalt Mg content. In terms of sequestering CO2, an average basaltic MgO content of 8% is equivalent to 2.6 × 108 metric ton CO2/km3 basalt.

  13. Landscape reorganization under changing climatic forcing: Results from an experimental landscape

    NASA Astrophysics Data System (ADS)

    Singh, Arvind; Reinhardt, Liam; Foufoula-Georgiou, Efi

    2015-06-01

    Understanding how landscapes respond to climate dynamics in terms of macroscale (average topographic features) and microscale (landform reorganization) is of interest both for deciphering past climates from today's landscapes and for predicting future landscapes in view of recent climatic trends. Although several studies have addressed macro-scale response, only a few have focused on quantifying smaller-scale basin reorganization. To that goal, a series of controlled laboratory experiments were conducted where a self-organized complete drainage network emerged under constant precipitation and uplift dynamics. Once steady state was achieved, the landscape was subjected to a fivefold increase in precipitation (transient state). Throughout the evolution, high-resolution spatiotemporal topographic data in the form of digital elevation models were collected. The steady state landscape was shown to possess three distinct geomorphic regimes (unchannelized hillslopes, debris-dominated channels, and fluvially dominated channels). During transient state, landscape reorganization was observed to be driven by hillslopes via accelerated erosion, ridge lowering, channel widening, and reduction of basin relief as opposed to channel base-level reduction. Quantitative metrics on which these conclusions were based included slope-area curve, correlation analysis of spatial and temporal elevation increments, and wavelet spectral analysis of the evolving landscapes. Our results highlight that landscape reorganization in response to increased precipitation seems to follow "an arrow of scale": major elevation change initiates at the hillslope scale driving erosional regime change at intermediate scales and further cascading to geomorphic changes at the channel scale as time evolves.

  14. Hertzian impact: experimental study of the force pulse and resulting stress waves.

    PubMed

    McLaskey, Gregory C; Glaser, Steven D

    2010-09-01

    Ball impact has long been used as a repeatable source of stress waves in solids. The amplitude and frequency content of the waves are a function of the force-time history, or force pulse, that the ball imposes on the massive body. In this study, Glaser-type conical piezoelectric sensors are used to measure vibrations induced by a ball colliding with a massive plate. These measurements are compared with theoretical estimates derived from a marriage of Hertz theory and elastic wave propagation. The match between experiment and theory is so close that it not only facilitates the absolute calibration the sensors but it also allows the limits of Hertz theory to be probed. Glass, ruby and hardened steel balls 0.4 to 2.5 mm in diameter were dropped onto steel, glass, aluminum, and polymethylmethacrylate plates at a wide range of approach velocities, delivering frequencies up to 1.5 MHz into these materials. Effects of surface properties and yielding of the plate material were analyzed via the resulting stress waves and simultaneous measurements of the ball's coefficient of restitution. The sensors are sensitive to surface normal displacements down to about +/-1 pm in the frequency range of 20 kHz to over 1 MHz. PMID:20815445

  15. Automated transient thermography for the inspection of CFRP structures: experimental results and developed procedures

    NASA Astrophysics Data System (ADS)

    Theodorakeas, P.; Avdelidis, N. P.; Hrissagis, K.; Ibarra-Castanedo, C.; Koui, M.; Maldague, X.

    2011-05-01

    In thermography surveys, the inspector uses the camera to acquire images from the examined part. Common problems are the lack of repeatability when trying to repeat the scanning process, the need to carry the equipment during scanning, and long setting-up time. The aim of this paper is to present transient thermography results on CFRP plates for assessing different types of fabricated defects (impact damage, inclusions for delaminations, etc), as well as and to discuss and present a prototype robotic scanner to apply non destructive testing (thermographic scanning) on materials and structures. Currently, the scanning process is not automatic. The equipment to be developed, will be able to perform thermal NDT scanning on structures, create the appropriate scanning conditions (material thermal excitation), and ensure precision and tracking of scanning process. A thermographic camera that will be used for the image acquisition of the non destructive inspection, will be installed on a x, y, z, linear manipulator's end effector and would be surrounded by excitation sources (optical lamps), required for the application of transient thermography. In this work various CFRP samples of different shape, thickness and geometry were investigated using two different thermographic systems in order to compare and evaluate their effectiveness concerning the internal defect detectability under different testing conditions.

  16. Sex specificity of behavioral dominance and fasting endurance in wintering canvasbacks: Experimental results

    USGS Publications Warehouse

    Perry, M.C.; Nichols, J.D.; Conroy, M.J.; Obrecht, H.H., III; Williams, B.K.

    1988-01-01

    Hand-reared canvasbacks (Aythya valisineria) of varying sex ratios were maintained in pens during winter 1980-81 (3M-3F, 6M-0F, 0M-6F) and winter 1981-82 (4M-2F, 2M-4F) and fed two diets (control and stress). They were observed during feeding trials to determine intrasexual and intersexual aggressive activity. There was little evidence that either diet or sex ratio affected the total number of aggressive encounters. Females fed both control and stress diets were more aggressive and spent more time in the small feeding areas than males in pens with 3M-3F, 4M-2F, and 2M-4F sex ratios. Stressed ducks tended to weigh less than controls throughout the study. Females in the 3M-3F and 4M-2F pens weighed less than those in the 0M-6F and 2M-4F pens, respectively. However, relative weight changes throughout the winter were similar for males and females. Thus, results of these experiments do not lead to conclusive rejection of either the behavioral dominance hypothesis or the fasting endurance hypothesis.

  17. Mineralogical comparisons of experimental results investigating the biological impacts on rock transport processes.

    PubMed

    Wagner, Doris; Milodowski, Antoni E; West, Julia M; Wragg, Joanna; Yoshikawa, Hideki

    2013-08-01

    This study investigates the influence of microbes on fluid transport in sedimentary and igneous host rock environments. It particularly focuses on granodiorite rock (Äspö; Sweden) and mudstone (Horonobe; Japan) that were utilised during laboratory-based column experiments. The results showed that biofilms form on both rock types in low nutrient conditions. Cryogenic scanning electron microscopy showed that the morphology of biofilaments varied from filamentous meshwork (in crushed granodiorite column experiments) to clusters of rod-like cells (fracture surfaces in mudstone). X-ray diffraction analysis of the fine fractions (<5 µm) revealed the formation of secondary clay mineral phases within the crushed Äspö granodiorite rock substrate only. The formation of secondary clay minerals appears to be enhanced when bacteria are present. All experiments showed biofilm formation, bacterial enhanced trapping of fines blocking off pore throats and/or secondary clay mineral formation. These observations illustrate the importance of bacteria on rock transport properties which will impact on the containment and migration of contaminants. PMID:23770916

  18. Experimental verification of a tank to tank He II transfer model with trade study results

    NASA Technical Reports Server (NTRS)

    Yuan, S. W. K.; Frederking, T. H. K.

    1990-01-01

    A computer program has been developed to study the thermodynamics of tank to tank superfluid helium transfer. The model includes a supply and a receiver tank connected by a transfer line. The convey of He II from one tank to the other is controlled by a fountain effect pump (FEP). Phase separators are present in both the supply and receiver tank to regulate the bath temperature. Description of this model has been published elsewhere. In the present paper, data from a transfer experiment are used to verify the accuracy of this model. The experiment consisted of an FEP made of a 2-micron sintered stainless steel porous plug. Superfluid has been transferred from a liquid helium bath into a glass beaker. Bath temperatures, flowrate and heater power records are available. These results are compared to the predictions of the computer program and good agreement is found between the two. This model is very useful for the study and design of superfluid transfer systems, e.g., the Superfluid Helium Tanker (SFHT) and the Particle Astrophysics Magnet Facility (ASTROMAG).

  19. Experimentally activated immune defence in female pied flycatchers results in reduced breeding success.

    PubMed Central

    Ilmonen, P; Taarna, T; Hasselquist, D

    2000-01-01

    Traditional explanations for the negative fitness consequences of parasitism have focused on the direct pathogenic effects of infectious agents. However, because of the high selection pressure by the parasites, immune defences are likely to be costly and trade off with other fitness-related traits, such as reproductive effort. In a field experiment, we immunized breeding female flycatchers with non-pathogenic antigens (diphtheria-tetanus vaccine), which excluded the direct negative effects of parasites, in order to test the consequences of activated immune defence on hosts' investment in reproduction and self-maintenance. Immunized females decreased their feeding effort and investment in self-maintenance (rectrix regrowth) and had lower reproductive output (fledgling quality and number) than control females injected with saline. Our results reveal the phenotypic cost of immune defence by showing that an activated immune system per se can lower the host's breeding success. This may be caused by an energetic or nutritional trade-off between immune function and physical workload when feeding young or be an adaptive response to 'infection' to avoid physiological disorders such as oxidative stress and immunopathology. PMID:10821610

  20. Experimental results from pressure testing a 1:6-scale nuclear power plant containment

    SciTech Connect

    Horschel, D.S.

    1992-01-01

    This report discusses the testing of a 1:6-scale, reinforced-concrete containment building at Sandia National Laboratories, in Albuquerque, New Mexico. The scale-model, Light Water Reactor (LWR) containment building was designed and built to the American Society of Mechanical Engineers (ASME) code by United Engineers and Constructors, Inc., and was instrumented with over 1200 transducers to prepare for the test. The containment model was tested to failure to determine its response to static internal overpressurization. As part of the US Nuclear Regulatory Commission`s program on containment integrity, the test results will be used to assess the capability of analytical methods to predict the performance of containments under severe-accident loads. The scaled dimensions of the cylindrical wall and hemispherical dome were typical of a full-size containment. Other typical features included in the heavily reinforced model were equipment hatches, personnel air locks, several small piping penetrations, and a ihin steel liner that was attached to the concrete by headed studs. In addition to the transducers attached to the model, an acoustic detection system and several video and still cameras were used during testing to gather data and to aid in the conduct of the test. The model and its instrumentation are briefly discussed, and is followed by the testing procedures and measured response of the containment model. A summary discussion is included to aid in understanding the significance of the test as it applies to real world reinforced concrete containment structures. The data gathered during SIT and overpressure testing are included as an appendix.