Sample records for energy experimental results

  1. 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.

  2. High energy imploding liner experiment HEL-1: Experimental results

    SciTech Connect

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

    1997-09-01

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

  3. 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.

  4. 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).

  5. Experimental results from the Thermal Energy Storage-1 (TES-1) flight experiment

    NASA Astrophysics Data System (ADS)

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

    1995-09-01

    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).

  6. 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.

  7. Experimental results on antiproton-nuclei annihilation cross section at very low energies

    NASA Astrophysics Data System (ADS)

    Aghai-Khozani, H.; Barna, D.; Corradini, M.; Hayano, R.; Hori, M.; Kobayashi, T.; Leali, M.; Lodi-Rizzini, E.; Mascagna, V.; Prest, M.; Soter, A.; Todoroki, K.; Vallazza, E.; Venturelli, L.; Zurlo, N.

    2014-03-01

    Investigating the antiproton cross section on nuclei at low energies (1 eV - 1 MeV) is of great interest for fundamental cosmology and nuclear physics as well. The process is of great relevance for the models which try to explain the matter/antimatter asymmetry in the universe assuming the existence of the so-called "island" where antinucleon-nucleon annihilations occur in the border region [1]. For the nuclear physics point of view, the annihilation process is considered a useful tool to evaluate the neutron/proton ratio probing the external region of the nucleus. Moreover, the cross section measured at LEAR in the 80s-90s showed an unexpected behaviour for energies below 1 MeV. The results showed a saturation with the atomic mass number against the A2/3 trend which is known for higher energies. The ASACUSA collaboration at CERN measured 5.3 MeV antiproton annihilation cross section on different nuclei whose results demonstrated to be consistent with the black-disk model with the Coulomb correction [2]. So far, experimental limits prevented the data acquisition for energies below 1 MeV. In 2012 the 100 keV region has been investigated for the first time [3]. We present here the results of the experiment.

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

    SciTech Connect

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

    2008-07-08

    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.

  9. Experimental results from RO-PRO: a next generation system for low-energy desalination.

    PubMed

    Achilli, Andrea; Prante, Jeri L; Hancock, Nathan T; Maxwell, Eric B; Childress, Amy E

    2014-06-01

    A pilot system was designed and constructed to evaluate reverse osmosis (RO) energy reduction that can be achieved using pressure-retarded osmosis (PRO). The RO-PRO experimental system is the first known system to utilize energy from a volume of water transferred from atmospheric pressure to elevated pressure across a semipermeable membrane to prepressurize RO feedwater. In other words, the system demonstrated that pressure could be exchanged between PRO and RO subsystems. Additionally, the first experimental power density data for a RO-PRO system is now available. Average experimental power densities for the RO-PRO system ranged from 1.1 to 2.3 W/m2. This is higher than previous river-to-sea PRO pilot systems (1.5 W/m2) and closer to the goal of 5 W/m2 that would make PRO an economically feasible technology. Furthermore, isolated PRO system testing was performed to evaluate PRO element performance with higher cross-flow velocities and power densities exceeding 8 W/m2 were achieved with a 28 g/L NaCl draw solution. From this empirical data, inferences for future system performance can be drawn that indicate future RO-PRO systems may reduce the specific energy requirements for desalination by ?1 kWh/m3. PMID:24798068

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

    NASA Astrophysics Data System (ADS)

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

    2013-09-01

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

  11. Experimental results from the Thermal Energy Storage1 (TES1) flight experiment

    Microsoft Academic Search

    Lawrence W. Wald; Carol Tolbert; David Jacqmin

    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

  12. 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

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

    NASA Astrophysics Data System (ADS)

    Mashnik, S. G.

    2011-05-01

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

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

    SciTech Connect

    Mashnik, Stepan G [Los Alamos National Laboratory

    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.

  15. 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.

  16. TMX-U experimental results

    SciTech Connect

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

    1983-08-31

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

  17. Experimental study and computer simulations of the energy loss straggling of slow ions in thin foils: Results for H+ and D+ in C, Si, Cu, Ag and Bi

    NASA Astrophysics Data System (ADS)

    Celedón, C. E.; Cantero, E. D.; Lantschner, G. H.; Arista, N. R.

    2013-11-01

    We present an experimental and computer simulation study of the energy loss straggling of low energy (2-10 keV) proton and deuteron beams in C, Si, Cu, Ag and Bi. The measurements were done using the transmission technique with several self-supporting foils with thicknesses in the range of 13-25 nm. The computer simulations were based on a Monte Carlo code which provides a method to analyze in detail the influence of various effects, such as foil roughness and slowing down of the ions in the medium. The theoretical model for the stopping and straggling coefficients is based on the Density Functional Theory. The results of the simulations yield a good agreement with the experimental values for the total straggling, taking into account the target roughness which significantly increases the measured energy widths. Within the experimental uncertainties the results show a linear dependence of the energy loss straggling with the projectile velocity and no isotopic effects. The results clearly indicate that a quantitative analysis of the energy loss straggling in this energy range requires a careful evaluation of the foil roughness effect.

  18. 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.

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

    E-print Network

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

    2015-01-01

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

  20. CSCM: Experimental and Simulation Results

    E-print Network

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

    2014-01-01

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

  1. Experimental results on Zc(3900)

    NASA Astrophysics Data System (ADS)

    Shen, C. P.

    2015-10-01

    This report reviewed the recently discovered Zc(3900) at around 3.9 GeV/c2 in the ?±J/? mass spectrum by the Belle and BESIII collaborations simultaneously. Belle collaboration observed it in the process e+e- ? ?+?- J/? within the Y (4260) signal region with a 967 fb-1 data sample using initial-stateradiation technology. BESIII collaboration discovered it in the same process at a fixed center-of-mass energy of 4.260 GeV using a 525 pb-1 data sample. The measured resonance masses and widths from Belle and BESIII measurements are consistent with each other within the errors. The Zc(3900) can be interpreted as a new charged charmonium-like state.

  2. Conformational transitions in viroids and virusoids: comparison of results from energy minimization algorithm and from experimental data.

    PubMed

    Steger, G; Hofmann, H; Förtsch, J; Gross, H J; Randles, J W; Sänger, H L; Riesner, D

    1984-12-01

    Viroids are single-stranded circular RNA molecules of 240 to 400 nucleotides which are pathogens of certain higher plants and replicate autonomously in the host cell. Virusoids are similar to viroids in respect to size and circularity but replicate only as genomic part of a plant virus. Their structure and structural transitions have been investigated by thermo-dynamic, kinetic and hydrodynamic methods. The special features of the sequences of these RNAs, which are the basis for their secondary structures and structural flexibility, are investigated with theoretical methods. A set of thermodynamic parameters for helix growth and loop formation is selected from the literature to calculate secondary structures and structural transitions of single-stranded RNAs. Appropriate modifications of the chosen parameter set are discussed. For calculations we used either Tinoco-plots and the model of "cooperative helices" or the Zuker-program based on the exact algorithm of Nussinov et al, or both. Calculations were done for viroids and virusoids. As both are single-stranded, circular RNAs we had to modify the Zuker-program as described in the appendix. Calculations are done for different viroids, i.e. potato spindle tuber, citrus exocortis, chrysanthemum stunt, coconut cadang-cadang, and avocado sunblotch, and for two virusoids, i.e. the circular RNAs of Solanum nodiflorum mottle virus, and velvet tobacco mottle virus. For viroids the calculations confirm our earlier theoretical and experimental results about the extended native structure and the highly cooperative transition into a branched structure. Virusoids show less base pairing, branching in the native secondary structure, and only low cooperativity during denaturation. They resemble more closely the properties of random sequences with length, G:C content, and circularity as in viroids but statistical sequences. The comparison of viroids, virusoids, and circular RNA or random sequences confirms the uniqueness of viroid structure. PMID:6086063

  3. Experimental Results for IDDQ and VLV Testing

    Microsoft Academic Search

    Jonathan T.-Y. Chang; Chao-wen Tseng; Yi-chin Chu; Sanjay Wattal; Mike Purtell; Edward J. Mccluskey

    1998-01-01

    An experimental test chip was designed and manufactured to evaluate different test techniques. Based on the results presented in the wafer probe, 309 out of 5491 dies that passed the Stage 1 tests were packaged for further investigation. This paper describes the experimental setup and the preliminary results for the final package test. We focus on the correlation among various

  4. The Samarkand EAS installation and experimental results

    NASA Astrophysics Data System (ADS)

    Makhmudov, B. M.; Sirodzhev, N. S.; Alimov, T. A.; Aliev, N. A.; Kakhkharov, M. K.; Khamikov, N. Kh.; Vernov, S. N.; Khristiansen, G. B.

    1982-09-01

    The Samarkand University extensive-air-shower installation is briefly described, and experimental results obtained at this installation are discussed. It is shown that the spatial distribution of EAS Cerenkov emission at distances of 10-100 m from the EAS axis with respect to shape and absolute value given a purely protonic composition of the primary radiation can be made compatible with the scaling model only under the assumption of an anomalously sharp increase with energy of the cross section of the inelastic interactions of hadrons with atomic air nuclei. In addition, it is shown that the Xmax(E0) relationship (Xmax is the position of the maximum of an individual EAS) obtained at E0 exceeding 10 to the 17th eV on the basis of Yakutsk data does not contradict Samarkand data at E0 = 10 to the 16th eV.

  5. Low-energy NN tensor force from {rvec n}-{rvec p} scattering: Results of an accurate experimental approach

    SciTech Connect

    Walston, J. R.; Gould, C. R.; Haase, D. G.; Raichle, B. W.; Seely, M. L.; Tornow, W.; Wilburn, W. S.; Penttila'', S. I.; Hoffmann, G. W.

    2001-01-01

    The spin-dependent neutron-proton total cross-section differences {Delta}{sigma}{sub L} and {Delta}{sigma}{sub T} have been measured between E{sub n}=5 and 20 MeV in longitudinal and transverse nucleon spin orientations. From these data the {sup 3}S{sub 1}-{sup 3}D{sub 1} mixing parameter {epsilon}{sub 1}, which characterizes the nucleon-nucleon tensor force at low and intermediate energies, was determined in a model-insensitive way. In combination with measurements at higher energies, our values for {epsilon}{sub 1} support a nucleon-nucleon tensor interaction that is stronger than predicted by all modern high-precision nucleon-nucleon potential models and phase-shift analyses.

  6. An Overview of STAR Experimental Results

    E-print Network

    N. Xu

    2014-08-15

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

  7. The Reaction X + Cl 2?XCl + Cl (X = Mu, H, D). II. Comparison of experimental data with theoretical results derived from a new potential energy surface

    NASA Astrophysics Data System (ADS)

    Connor, J. N. L.; Jakubetz, W.; Lagana, A.; Manz, J.; Whitehead, J. C.

    1982-02-01

    We consider experimental implications for the Mu + Cl 2, H + Cl 2, and D + Cl 2 reactions of the extended London—Eyring—Polanyi—Sato (LEPS) potential energy surface derived from experimental data in paper I. In the present calculations, it is necessary to make additional implicit and explicit assumptions concerning the three-dimensional (3D) nature of the potential surface, since the inversion procedure of paper I yields information only on the collinear (1D) part of the surface. We have performed accurate 1D quantum calculations of reaction probabilities, which are then transformed into 3D by an information theoretic 1D ? 3D transformation incorporating a constraint to allow for angular momentum transfer effects in light+heavy—heavy atom reactions. This procedure implicitly accounts for the 3D nature of the potential surface. The calculated vibrational and vibrotational product distributions are in good agreement with those determined in thermal chemiluminescence experiments. The Sato parameters for the 1D surface also define a full 3D surface. This is used as an approximation to the true surface, and its properties are explored in 3D quasiclassical trajectory calculations. Comparison is made for the H and D reactions with available chemiluminescence, molecular beam and kinetic experimental data for differential and total reaction cross sections, energy disposal, rate coefficients and Arrhenius parameters. Some kinetic isotope effects in the Mu, H, and D reactions are discussed using vibrationally adiabatic theory. Comparison is also made with results from other calculations in the literature for the H + Cl 2 and D + Cl 2 reactions.

  8. A summary of recent experimental results from Mark J: High energy e/sup +/e/sup /minus// collisions at PETRA: Report Number 131

    SciTech Connect

    Adeva, B.; Barber, D.P.; Becker, U.; Berdugo, J.; Bohm, A.; Branson, J.G.; Burger, J.D.; Capell, M.; Cerrada, M.; Chang, C.C.

    1983-12-01

    The PETRA electron-positron collider at DESY in Hamburg, Federal Republic of Germany, began operating in 1978, with four intersection regions devoted to experiments. In the intervening five years, five detector devices, CELLO, JADE, MARK-J, PLUTO and TASSO have accumulated and published a substantial variety of experimental results. The limits of validity of Quantum Electro-Dynamics (QED) have been extended; the pointlike nature of leptons and quarks have been probed at exceedingly small distances; the Glashow, Weinberg and Salam (GWS) '' standard electroweak model'' has been tested and found to describe interactions remarkably well; the predicted interference between electromagnetic and weak forces has been conclusively demonstrated; events with three jets have been discovered and interpreted as resulting from gluons, as predicted by Quantum Chromo-Dynamics (QCD); the sixth, ''top,'' quark has not been found yet, although an energy search for ''toponium'' (top + antitop) has been carried out up to 43.1 GeV center of mass energy. An integrated luminosity of about 100 pb/sup /minus/1/ mostly at energies above 30 GeV, has produced a very large sample of events. The present paper is a complete review and up-dating of all MARK-J physics results either published or unpublished. Since the amount of interesting information is so large, we realized that a coherent summation could be of substantial usefulness to the community. In order that this review can serve many needs, we include, a brief description of the apparatus and the data acquisition and analysis.

  9. RECENT RESULTS OF EXPERIMENTATION AND DEM MODELING

    E-print Network

    Paris-Sud XI, Université de

    RECENT RESULTS OF EXPERIMENTATION AND DEM MODELING OF CENTRIFUGAL FERTILIZER SPREADING E. Tijskens1 , P. Van Liedekerke1 , E Piron2 , J. Van Geyte3 , Sylvain Villette4, H. Ramon1 1. Faculty of Bio-engineering running several industrial research projects on centrifugal fertilizer projects (Tijskens et al. 2005). 1

  10. Abstracting Soft Constraints: Some Experimental Results

    E-print Network

    Rossi, Francesca

    Abstracting Soft Constraints: Some Experimental Results F. Rossi, I. Pilan Universit#18;a di Padova@math.unipd.it, ipilan@studenti.math.unipd.it Abstract. Soft constraints are very exible and expressive. However to an abstract version of a given soft problem, and then to bring some useful information from the abstract

  11. Mach 5 inlet CFD and experimental results

    NASA Technical Reports Server (NTRS)

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

    1989-01-01

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

  12. Microwave radiometry for humanitarian demining: experimental results

    NASA Astrophysics Data System (ADS)

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

    2002-08-01

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

  13. PDX experimental results in FY82

    SciTech Connect

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

    1983-08-01

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

  14. Oxidation Lifetimes: Experimental Results and Modeling

    Microsoft Academic Search

    I. G. Wright; B. A. Pint; L. M. Hall; P. F. Tortorelli

    Experimental results for high-temperature alloys with excellent oxidation resistance strongly suggest that their oxidation behavior involves several distinct stages that are not well addressed in current models. An approach is suggested that relies on breaking the 'steady-state' oxidation stage into multiple stages. In higher-temperature experiments, two such stages are clearly observed, whereas at more relevant, lower temperatures, these stages are

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

    Microsoft Academic Search

    H. Kreetz; K. Lovegrove

    1999-01-01

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

  16. 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.

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

    Microsoft Academic Search

    Samuel Allison

    1958-01-01

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

  18. 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.

  19. Initial experimental results of CAEP photoinjector

    NASA Astrophysics Data System (ADS)

    Yang, Mao-rong; Du, Xing-shao; Li, Zheng-hong; Li, Ming; Ke-song Hu; Qian, Ming-quan; Pan, Qing; Chai, Gong-he; Xu, Zhou; Ren-pei Deng; Wu, Zhong-fa

    1998-02-01

    An RF photocathode gun which, along with a compact linac, forms the injection system for a planned FIR FEL amplifier experiment, has been commissioned in the high power radiation laboratory. This high-gradient gun has emitted 60 ps, 10 A electron beams of up to 3 MeV energy. These beams have been characterized by a variety of diagnostics. The quantum efficiency of Cs 2Te has been measured at normal incidence. The energy and energy spread of the beam were tested using a dipole spectrometer, while the time structure was examined with a picosecond resolution streak camera. The emittance of the beam was measured using the pepper pot technique and its dependence on space charge and RF phase were found. The impact of these results on improving the design and operation of this high brightness photoinjector is discussed. This injector will be applied to the FIR FEL project in future.

  20. 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.

  1. 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.

  2. 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.

  3. Overview of the initial NSTX experimental results

    NASA Astrophysics Data System (ADS)

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

    2001-10-01

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

  4. Experimental Results on Rotor Wakes Narayanan Komerath

    E-print Network

    -Gray deconstruction of the hover wake structure into tip vortices and helical vortex sheets, done in the early 1960s through chaotic processes, even at high Reynolds number. Similarly, mysterious "jitter" phenomena have these advances, shown both experimentally and through analysis and computation, it has become possible

  5. Experimental Results on Advanced Rotary Desiccant Dehumidifiers 

    E-print Network

    Barathan, D.; Parsons, J. M.; MaClaine-Cross, I.

    1986-01-01

    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...

  6. MODEL COMPARISONS WITH STELLA EXPERIMENTAL RESULTS.

    SciTech Connect

    KIMURA,W.D.; BABZIEN,M.; BEN-ZVI,I.; ET AL.

    2004-09-15

    High-trapping efficiency and narrow energy spread in a staged laser acceleration system was demonstrated during the Staged Electron Laser Acceleration (STELLA) experiment. The experiment used inverse free electron lasers (IFEL) driven by the Brookhaven National Laboratory Accelerator Test Facility (ATF) CO{sub 2} laser. The 1st IFEL modulated the electron beam energy. A subsequent chicane created a train of {approx}3 fs-long microbunches separated by 10.6 microns. These microbunches are trapped and accelerated in a 2nd IFEL where up to 80% trapping efficiencies and energy spreads down to 0.36% (1-{delta}) were measured. This paper presents additional model comparisons with the data, and discusses the strengths and limitations of the model.

  7. Experimental results of the betatron sum resonance

    SciTech Connect

    Wang, Y.; Ball, M.; Brabson, B. [Indiana Univ., Bloomington, IN (United States)] [and others

    1993-06-01

    The experimental observations of motion near the betatron sum resonance, {nu}{sub x} + 2{nu}{sub z} = 13, are presented. A fast quadrupole (Panofsky-style ferrite picture-frame magnet with a pulsed power supplier) producing a betatron tune shift of the order of 0.03 at rise time of 1 {mu}s was used. This quadrupole was used to produce betatron tunes which jumped past and then crossed back through a betatron sum resonance line. The beam response as function of initial betatron amplitudes were recorded turn by turn. The correlated growth of the action variables, J{sub x} and J{sub z}, was observed. The phase space plots in the resonance frame reveal the features of particle motion near the nonlinear sum resonance region.

  8. 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.

  9. Numerical taxonomy on data: Experimental results

    SciTech Connect

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

    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.

  10. [Focused extracorporeal pyrotherapy. Initial experimental results].

    PubMed

    Vallancien, G; Chopin, D; Davila, C; Guiillonneau, B; Perreira, E; Veillon, B; Brisset, J M; Andre-Bougaran, J

    1991-02-01

    The objective of this study was to develop an apparatus allowing the generation of a high temperature (exceeding 80 degrees C) in a precise focus (20 mm x 2 mm) by means of extracorporeal elastic waves. The treatment time at high temperatures is brief and administered in sequences of 4 to 7 seconds. In vitro studies on blocks of polyurethane demonstrated melting of the plastic at the focal point. Studies on plastic spheres introduced into the bladder of the pig demonstrated melting of the sphere without any alteration in the tissues in the wave path. Studies of cellular viability of bladder carcinoma cultures demonstrated a significant difference after 48 hours between the non-treated control group and the group of cells submitted to high temperatures. This technique, called Pyrotherapy, should be promising if the preliminary results are confirmed. PMID:1285392

  11. Inviscid Flow Field Effects: Experimental results

    NASA Astrophysics Data System (ADS)

    Otten, L. J., III; Gilbert, K. G.

    1980-04-01

    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.

  12. Experimental results from the TFTR tokamak

    SciTech Connect

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

    1986-10-01

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

  13. Experimental High Energy Neutrino Astrophysics

    SciTech Connect

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

    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.

  14. 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).

  15. Blanking and piercing theory, applications and recent experimental results

    NASA Astrophysics Data System (ADS)

    Zaid, Adnan l. O.

    2014-06-01

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

  16. Experimental results of an electron cyclotron resonance oxygen source and a low energy beam transport system for 1 MeV integral split ring radio frequency quadruple accelerator upgrade project.

    PubMed

    Peng, S X; Zhang, M; Song, Z Z; Xu, R; Zhao, J; Yuan, Z X; Yu, J X; Chen, J; Guo, Z Y

    2008-02-01

    To meet the requirements of developing separated function radio frequency quadruple (rfq) and upgrading the 1 MeV integral split ring rfq accelerator, an electron cyclotron resonance O(+) ion source and low energy beam transport (LEBT) system have been developed. Using two Einzel lenses to focus the beam, more than 6 mA O(+) peak beam current with energy of 22 keV can be easily obtained at the end of LEBT when the duty faction is at 1/6. The normalized root-mean-square emittance of 90% of the beam is about 0.12pi mm mrad. By changing the focusing power of lenses, the beam waist can be shifted from 80 mm before the beam diaphragm 2 to 80 mm after it. The experimental results will be presented in this article. PMID:18315197

  17. Experimental results for the interference between FM television signals

    NASA Technical Reports Server (NTRS)

    Groumpos, P. P.; Vernon, G. D.

    1981-01-01

    Experimental results based on subjective evaluation of picture quality of FM television systems are presented. Curves indicating the variation in protection ratio with impairment grade are provided. Such an analysis would be useful to the broadcasting satellite system designer. The experimental procedures and test conditions followed are briefly summarized. The need for a theoretical planning method is briefly discussed.

  18. 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. .

  19. Theoretical and Experimental Results Regarding LENR\\/CF

    Microsoft Academic Search

    Robert W. Bass; Wm. Stan Gleeson

    2000-01-01

    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

  20. 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).

  1. Summary of Experimental Results: Photons, Leptons and Heavy Quarks

    E-print Network

    Richard Seto

    2008-07-23

    This is a summary of experimental results on photons, leptons, and heavy quarks presented at Quark Matter 2008. A first measurement of the bottom to charm contribution to the lepton spectrum has given experimental indication for the suppression of charm and bottom. Excess dileptons have been observed and studied by both NA60 and PHENIX, which may arise from the early production of thermal dileptons and/or the modification of mesons.

  2. Experimental analysis on vortex tube energy separation performance

    NASA Astrophysics Data System (ADS)

    Hamdan, Mohammad O.; Alawar, Ahmed; Elnajjar, Emad; Siddique, Waseem

    2011-12-01

    The present study reports the effect of several operating parameters on the thermal performance of the vortex tube. The experimental results indicate that the inlet pressure and the cold fraction are the most significant parameters influencing the vortex tube performance. The experimental data point out that insulation has minimal effect on the vortex tube performance. The same inlet pressure tests show that energy separation increases as number of inlet nozzle increases.

  3. The parametric propagation in underwater acoustics: experimental results

    E-print Network

    Paris-Sud XI, Université de

    acoustics, detection of buried objects in sediments (cables, mines, ...) is a complex problem. IndeedThe parametric propagation in underwater acoustics: experimental results E. Bouttarda , V. Labata.bouttard@ecole-navale.fr Proceedings of the Acoustics 2012 Nantes Conference 23-27 April 2012, Nantes, France 209 #12;In underwater

  4. High-efficiency diode-pumped rubidium laser: experimental results

    Microsoft Academic Search

    Ty A. Perschbacher; David A. Hostutler; T. M. Shay

    2007-01-01

    A diode-pumped rubidium laser with an optical slope efficiency of 69% has been constructed. This study utilized a narrow-line diode laser pump source for the experiments. The trade space study included optimization of various parameters such as lasing cell composition, temperature, and output coupler reflectivities. The results of the experimental study are given.

  5. 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 of today's students obtained from extensive use of interactive computer games. This paper presents a design

  6. The yield strength of subliquidus basalts — experimental results

    Microsoft Academic Search

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

    2001-01-01

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

  7. Experimental Measurement of Low Energy Neutrino Interactions

    SciTech Connect

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

    2011-11-23

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

  8. Design and experimental results for the S809 airfoil

    SciTech Connect

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

    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.

  9. 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.

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

    Microsoft Academic Search

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

    2009-01-01

    We present experimental results of plasma jet, interacted with an ambient medium, using intense lasers to investigate the\\u000a complex features of astrophysical jets. This experiment was performed in France at the LULI facility, Ecole Polytechnique,\\u000a using one long pulse laser to generate the jet and a short pulse laser to probe it by proton radiography. A foam filled cone\\u000a target

  11. 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.

  12. Organic ferromagnets: New approaches and new experimental results (abstract)

    NASA Astrophysics Data System (ADS)

    Torrance, J. B.; Oostra, S.; Nazzal, A.; Johannsen, I.; Bechgaard, K.

    1987-04-01

    Different models and proposals are reviewed for synthesizing an organic ferromagnet, including a particularly simple and promising new model for making a solid containing ferromagnetically aligned organic radicals. A number of new experimental results are described and compared with these approaches. For example, new polymers based on s-triaminobenzene have been synthesized. These materials appear to show ferromagnetic interactions at room temperature and represent the first organic ferromagnet.

  13. Shared-spectrum multistatic radar: Preliminary experimental results

    Microsoft Academic Search

    Aaron K. Shackelford; Jean de Graaf; S. Talapatra; K. Gerlach; S. D. Blunt

    2007-01-01

    In this paper we present preliminary experimental results demonstrating the ability of the multistatic adaptive pulse compression (MAPC) algorithm to suppress the mutual-interference generated by shared-spectrum radar signals, thus enabling shared-spectrum radar. The MAPC algorithm, a waveform diversity technique wherein multiple known transmitted waveforms are adaptively pulse compressed using reiterative minimum mean-square error (RMMSE) estimation, has been shown to successfully

  14. Experimental Results on Indoor Localization Techniques through Wireless Sensors Network

    Microsoft Academic Search

    Thomas Pavani; Guido Costa; Marco Mazzotti; Andrea Conti; Davide Dardari

    2006-01-01

    In this paper we present the results of an intensive experimental campaign performed at IEIIT-BO\\/CNR, Bologna, Italy, on an indoor localization system based on wireless sensors network. Received signal strength indications have been measured and collected using real devices. The data serve as an input data-base for an off-line investigation of different localization techniques. This enables us on one side

  15. [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)

  16. Calculating an unknown source activity using modeled and experimental results.

    PubMed

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

    2014-11-01

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

  17. Experimental Results for Titan Aerobot Thermo-Mechanical Subsystem Development

    NASA Technical Reports Server (NTRS)

    Pauken, Michael T.; Hall, Jeffery L.

    2006-01-01

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

  18. Bessel beam ultrasonic transducer: Fabrication method and experimental results

    SciTech Connect

    Hsu, D.K.; Margetan, F.J.; Thompson, D.O. (Ames Laboratory, Iowa State University, Ames, Iowa 50011 (US))

    1989-11-13

    We report experimental results from a first-of-a-kind ultrasonic transducer that generates a beam with a Bessel function profile. Using a technique of nonuniform poling, an axially symmetric Bessel function pattern is polarized into'' a piezoelectric ceramic element. The resulting circular-disk transducer has the usual full-plating electrode configuration, but produces an ultrasonic beam with a radial displacement profile approximating that of the Bessel function {ital J}{sub 0} ({ital r}), both in amplitude and in phase. The radiation field of a 1-in.-diam, 2.25 MHz Bessel transducer mapped out with a point probe shows good agreement with calculated results using a Gauss-Hermite model. Bessel transducers are of particular interest in attempts to achieve diffractionless'' beams.

  19. Comparison of computational and experimental results for a supercritical airfoil

    NASA Technical Reports Server (NTRS)

    Rivers, Melissa B.; Wahls, Richard A.

    1994-01-01

    A computational investigation was performed to study the flow over a supercritical airfoil model. Solutions were obtained for steady-state transonic flow conditions using a thin-layer Navier-Stokes flow solver. The results from this computational study were compared with time-averaged experimental data obtained over a wide Reynolds number range at transonic speeds in the Langley 0.3-Meter Transonic Cryogenic Tunnel. Comparisons were made at a nominal Mach number of 0.72 and at Reynolds numbers ranging from 6 x 10(exp 6) to 35 x 10(exp 6).

  20. Single And Double Pulse Irradiation And Comparison With Experimental Results

    SciTech Connect

    Fornarini, L.; Fantoni, R.; Colao, F. [ENEA, FIM-FISLAS, Via E. Fermi 45, I-00044, Frascati (Italy); Santagata, A. [CNR-IMIP Unita Operativa di Potenza, Zona Industriale-85050 Tito Scalo (Italy); Teghil, R. [Universita degli Studi della Basilicata, Dip. Chimica, Via N. Sauro 85, 85100 Potenza (Italy)

    2009-09-27

    A theoretical model of laser ablation has been previously developed and applied to Laser Induced Breakdown Spectroscopy (LIBS) analysis of bronzes with the aim to improve quantitative results and to focus on problems arising in the interpretation of experimental data. The model describes laser-solid matter interaction, plume expansion, plasma formation and laser-plasma interaction. A two temperature approach has been also introduced to take into account the initial temperature dynamics of the alloy surface upon ultra-short laser irradiation. We examined various target compositions, typical of archaeological artworks, and different laser characteristics such as wavelength (355 nm, 530 nm, 1064 nm) and pulse duration (8 ns, 250 fs). In this work, the model has been extended to simulate double pulse LIBS configuration in order to clarify the mechanism involved in the process and for better interpreting the experimental data. Plasma composition, relevant parameters (temperature, electron density) and their kinetic evolutions have been measured. Results have been compared with the simulation obtained using the same irradiation conditions and set of targets.

  1. 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.

  2. Atmospheric turbulence correction using digital holographic detection: experimental results.

    PubMed

    Marron, Joseph C; Kendrick, Richard L; Seldomridge, Nathan; Grow, Taylor D; Höft, Thomas A

    2009-07-01

    The performance of long distance imaging systems is typically degraded by phase errors imparted by atmospheric turbulence. In this paper we apply coherent imaging methods to determine, and remove, these phase errors by digitally processing coherent recordings of the image data. In this manner we are able to remove the effects of atmospheric turbulence without needing a conventional adaptive optical system. Digital holographic detection is used to record the coherent, complex-valued, optical field for a series of atmospheric and object realizations. Correction of atmospheric phase errors is then based on maximizing an image sharpness metric to determine the aberrations present and correct the underlying image. Experimental results that demonstrate image recovery in the presence of turbulence are presented. Results obtained with severe turbulence that gives rise to anisoplanatism are also presented. PMID:19582079

  3. Global sensitivity analysis used to interpret biological experimental results.

    PubMed

    Jarrett, Angela M; Liu, Yaning; Cogan, N G; Hussaini, M Yousuff

    2015-07-01

    Modeling host/pathogen interactions provides insight into immune defects that allow bacteria to overwhelm the host, mechanisms that allow vaccine strategies to be successful, and illusive interactions between immune components that govern the immune response to a challenge. However, even simplified models require a fairly high dimensional parameter space to be explored. Here we use global sensitivity analysis for parameters in a simple model for biofilm infections in mice. The results indicate which parameters are insignificant and are 'frozen' to yield a reduced model. The reduced model replicates the full model with high accuracy, using approximately half of the parameter space. We used the sensitivity to investigate the results of the combined biological and mathematical experiments for osteomyelitis. We are able to identify parts of the compartmentalized immune system that were responsible for each of the experimental outcomes. This model is one example for a technique that can be used generally. PMID:25059426

  4. 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.

  5. Experimental Ultra--High-Energy Cosmic Ray Physics

    E-print Network

    Stefan Westerhoff

    2005-12-07

    One of the most striking astrophysical phenomena today is the existence of cosmic ray particles with energies in excess of 10^20 eV. While their presence has been confirmed by a number of experiments, it is not clear where and how these particles are accelerated to these energies and how they travel astronomical distances without substantial energy loss. We are entering an exciting new era in cosmic ray physics, with instruments now producing data of unprecedented quality and quantity to tackle the many open questions. This paper reviews the current experimental status of cosmic ray physics and summarizes recent results on the energy spectrum and arrival directions of ultra-high-energy cosmic rays.

  6. 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.

  7. 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

  8. Integrated radar-camera security system: experimental results

    NASA Astrophysics Data System (ADS)

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

    2011-06-01

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

  9. Experimental Results for Titan Aerobot Thermo-Mechanical Subsystem Development

    NASA Technical Reports Server (NTRS)

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

    2006-01-01

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

  10. Energy Monitoring - Objectives vs Results 

    E-print Network

    McEver, R. M.

    1985-01-01

    air and gas leaks with inplant metering have been repor ted.5 Accurate metering of natural gas has allowed one plant to pay off investment in metering in just five months. This sav ings is real ized by hav ing information to determine when...Plant Saves $50,0OO/Year By Averting Air and Gas Leaks With In-Plant Metering," Chemical Processinn, Mid-Nov em ber 1977, pp. 121-123. "Meteringt1, MedaxLnd!~strFam, November 1980, p. 13. 7. Foster, A. L. ItInformation Gathering for Energy Management...

  11. Recent experimental results and future plan in KSTAR

    NASA Astrophysics Data System (ADS)

    Kwak, Jong-Gu; Lee, Sang-Gon; Bae, Young-Sun; Park, Boung-Ho; Kim, Jin-Young; KSTAR Team

    2014-10-01

    In this talk, the recent results of KSTAR will be presented focusing on extention of operational boundary in long-pulse discharges and highlights in experimental physics. H-mode discharges has been sustained longer and the operational regime of plasma parameters has been significantly extended in terms of heating power and plasma current. The long-pulse operation is in accordance with ITER requirement, i.e., in ITER similar shape, low safety factor (q95 ~ 3) and normalized beta (~2.0) with real-time control of density and power. Both ELM suppression and mitigation are discovered in wide range of RMP coil configuration and the suppression window in the edge safety factor has extended from 6.5 to 3.9 indicating the strong impact of resonant component. Beside RMP ELM suppression, it is also investigated the effect of other techniques on ELMs, such as edge heating by ECH and cooling by SMBI. Detailed evaluation of error field (EF) has been performed by 4 segment compass scan by the internal coils and the measured level of intrinsic error field is an order of magnitude lower than other tokamaks. In addition to the above topics, it is summarized the recent results on rotation & transport physics, newly installed diagnostics, MHD and fast ion activities, followed by the near future plan.

  12. The Radiative Return: A Review of Experimental Results

    E-print Network

    Achim Denig

    2006-11-13

    The radiative return is a new method for hadronic cross section measurements at electron-positron colliders, which are operated at a fixed center-of-mass energy. In order to lower the effective hadronic mass M_hadr only such events are taken, in which one of the electrons or positrons has emitted an initial state radiation photon. We present precision measurements of the pion form factor from the Frascati phi-factory DAPHNE with the KLOE experiment and measurements of higher particle multiplicities as well as a measurement of the timelike proton-antiproton form factor from the BaBar experiment at the B-factory PEP-II. These radiative return measurements are compared to results, which are obtained by means of an energy scan, i.e. by means of a systematic variation of the beam energy of the collider. We also report on the impact of these measurements on the hadronic contribution of the anomalous magnetic moment of the muon, which is obtained via a dispersion integral using hadronic cross section data as input.

  13. Experimental study on a pendulum wave energy converter

    NASA Astrophysics Data System (ADS)

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

    2013-06-01

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

  14. PHENIX beam energy scan results

    NASA Astrophysics Data System (ADS)

    Soltz, R. A.

    2014-11-01

    We present results from the PHENIX Experiment for Au+Au collisions with ?{sNN} = 7.9 , 19.6 , 27 , 39 , 62 , and 200 GeV. Measurements of the charged particle multiplicity at central rapidity scale linearly with the number of participant quarks for ?{sNN} = 62 GeV and above; for ?{sNN} = 27 GeV and below the multiplicity scales with the number of participant nucleons. For the HBT radii we perform a linear interpolation for radii from PHENIX, STAR, and ALICE to a mT = 0.26 GeV and calculate ratios and differences in quadrature at this value of the transverse mass. We observe a non-monotonic behavior near ?{sNN} = 19 GeV in the form of a peak in Ro2 - Rs2 and a dip in (Rs -?{ 2} R bar) /Rl.

  15. Preliminary Experimental Result of Magnetic Reconnection in Laboratory Plasma

    NASA Astrophysics Data System (ADS)

    Zhang, S. B.; Xie, J. L.; Hu, G. H.; Li, H.; Huang, G. L.; Liu, W. D.

    2011-05-01

    Magnetic reconnection is one of the most important physical processes in astrophysical plasmas. Lots of theoretical works, numerical simulations and observations have been done. Some experimental programs have been activated to investigate the basic mechanisms of magnetic reconnection. In order to investigate the electron dynamic near the electron diffusion region in magnetic reconnection process, an upgrade is accomplished in the LMP (Linear magnetic plasmas) device at University of Science and Technology of China. The magnetic field of reconnection is produced by passing two identical currents axially through two copper plates. Magnetic field and parallel electric field are measured by magnetic probes and emissive probes, respectively. The existence of a large electric field related to the reconnection process is verified. The plasma is driven by electric field and magnetic field, so the magnetic reconnection appears. The magnitude of axial current is found to scale with the number of passing particles. In the configuration of current bars, passing particles are even more and our measured axial current is about 10 A. Magnetic flux doesn't pile up because of the parameter region in our case, which is consistent with the result of numerical simulation.

  16. Shuttle Upper Atmosphere Mass Spectrometer Experimental Flight Results

    NASA Technical Reports Server (NTRS)

    Blanchard, R. C.; Ozoroski, Thomas A.; Nicholson, John Y.

    1994-01-01

    Calibrated pressure measurements for species with mass-to-charge ratios up to 50 amu/e(-) were obtained trom the shuttle upper atmosphere mass spectrometer experiment during re-entry on the STS-35 mission. The principal experimental objective is to obtain measurements of freestream density in the hypersonic rarefied flow flight regime. Data were collected from 180 to about 87 km. However, data above 115 km were contaminated from a source of gas emanating from pressure transdueers connected in parallel to the mass spectrometer. At lower altitudes, the pressure transducer data are compared to the mass spectrometer total pressure with excellent agreement. Near the orifice entrance, a significant amount of CO2 was generated from chemical reactions. The freestream density in the rarefied flow flight regime is calculated using an orifice pressure coefficient model based upon direct simulation Monte Carlo results. This density, when compared with the 1976 U.S. Standard Atmosphere model, exhibits the wavelike nature seen on previous flights using accelerometry. Selected spectra are presented at higher altitudes (320 km) showing the effects of the ingestion of gases from a forward fuselage fuel dump.

  17. 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

  18. Experimental Results of Integrated Refrigeration and Storage System Testing

    NASA Astrophysics Data System (ADS)

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

    2010-04-01

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

  19. Experimental Results in DIS, SIDIS and DES from Jefferson Lab

    SciTech Connect

    Sebastian Kuhn

    2011-07-01

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

  20. Experimental Results in DIS, SIDIS and DES from Jefferson Lab

    SciTech Connect

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

    2011-07-15

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

  1. Bolus-tracking arterial spin labelling: theoretical and experimental results

    NASA Astrophysics Data System (ADS)

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

    2009-03-01

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

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

    Microsoft Academic Search

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

    2010-01-01

    The following interesting experimental results observed in Japan Proton Accelerator Research Complex (J-PARC) H- ion-source developments are reviewed. It was proven that almost all of H- ions were produced with surface reactions in cesium (Cs)-free J-PARC H- ion-sources. The world's most intense class H- ion current of 38 mA in Cs-free ion sources for a high-energy linac was attained by

  3. Experimental design methods and flowsheet synthesis of energy systems

    Microsoft Academic Search

    Tor-Martin Tveit

    2005-01-01

    This work presents a discussion of how to utilise well known methods from the field of experimental design in the flowsheet synthesis of energy systems. The work is based on an earlier work, where a methodology for improving large scale energy systems using a combination of simulation, experimental design and mathematical programming was presented. The methodology is suitable for synthesis

  4. 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. [Hughes Missile Systems Co., Rancho Cucamonga, CA (United States); Carlsten, B.E.; Fazio, M.V.; Haynes, W.B.; Stringfield, R.M. [Los Alamos National Lab., NM (United States)

    1994-12-31

    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.

  5. Experimental results of the European HELINOISE aeroacoustic rotor test

    Microsoft Academic Search

    W. R. Splettstoesser; G. Niesl; F. Cenedese; F. Nitti; D. G. Papanikas

    1995-01-01

    In a cooperative research program between eight European partners, a 40% geometrically and dynamically scaled and highly instrumented model of the ECD (formerly MBB) BO 105 helicopter main rotor was tested in the open-jet anechoic test section of the German-Dutch Wind Tunnel (DNW) in the Netherlands. The primary objectives of this experimental study were to: (1) to improve the physical

  6. Nonlinear fundamental photothermal response: experimental results for tungsten

    E-print Network

    Mandelis, Andreas

    and Industrial Engineering, University of Toronto, 5 King's College Road, Toronto, ON M5S 3G8, Canada Received 29 Elsevier Science Ltd. All rights reserved. Keywords: A. Metals; A. Thin films; D. Heat conduction 1 nonlinear photothermal deflection imaging experimentally, where the pump beam is modulated at angular

  7. BATCH VIBRATING FLUID BED DRYER FOR SAWDUST PARTICLES: EXPERIMENTAL RESULTS

    Microsoft Academic Search

    Rogelio Moreno; Rolando Rios; Héctor Calbucura

    2000-01-01

    In a batch experimental equipment, the behavior of a sawdust dryer in a vibrating fluidized bed is analyzed. Empirical data concerning fluidization velocities, pressure drops and drying kinetics was obtained, and advantages of using vibration in the drying chamber, relative to a conventional fluidized bed, are shown. This technique is presented as an alternative to solve problems of solid agglomeration

  8. Experimental Studies of Ion Beam Neutralization: Preliminary Results

    Microsoft Academic Search

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

    2011-01-01

    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

  9. 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.

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

    Microsoft Academic Search

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

    1997-01-01

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

  11. 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.

  12. Experimental Results for an Annular Aerospike with Differential Throttling

    NASA Technical Reports Server (NTRS)

    Ruf, Joseph H.; McDaniels, David M.

    2005-01-01

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

  13. Experimental results with endovascular irradiation via a radioactive stent

    Microsoft Academic Search

    Andrew J. Carter; John R. Laird

    1996-01-01

    Purpose: The objective of this article is to describe the methods used to manufacture a radioactive stent and to review the experimental data on this therapy designed to improve arterial patency rates after stent placement.Materials and Methods: Surface activation in a cyclotron and ion implantation techniques are used to render commercially available vascular stents radioactive. ?-Particle-emitting stents, most commonly 32P,

  14. Bicell fibre optics homodyne phase demodulator: experimental results

    NASA Astrophysics Data System (ADS)

    Holdynski, Z.; Merta, I.; Nasilowski, T.; Jaroszewicz, L. R.

    2013-05-01

    We present possibility of demodulation signals with different types of modulation. Our setup gives possibility to obtain high accuracy and precision of measurements. We explain how to optimize the setup to obtain optimum condition to phase demodulation for signals with different types of modulation. Real time phase measurements and stable working conditions are provided experimentally. Thermal stabilization and errors analysis based on geometrical and physical setup parameters is demonstrated and optimized, too. Our phase demodulation method is effective and simple in opposite to other phase decoding methods with are overloaded by digital signal processing steps.

  15. Experimental Studies of Ion Beam Neutralization: Preliminary Results

    NASA Astrophysics Data System (ADS)

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

    2011-05-01

    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.

  16. Titanium as reactor material for SCWO applications. First experimental results

    SciTech Connect

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

    1998-12-31

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

  17. Experimental Results on Statistical Approaches to Page Replacement Policies

    E-print Network

    Irani, Sandy

    Company, for the United States Department of Energy under contract DE­ AC04­94AL85000. Part of this work in advance. Cao, Felten, Karlin and Li investigate the question of how to integrate page replacement data to sim­ ulate the behavior of each algorithm on real paging sequences and report the fault rate

  18. CSI Flight Computer System and experimental test results

    NASA Technical Reports Server (NTRS)

    Sparks, Dean W., Jr.; Peri, F., Jr.; Schuler, P.

    1993-01-01

    This paper describes the CSI Computer System (CCS) and the experimental tests performed to validate its functionality. This system is comprised of two major components: the space flight qualified Excitation and Damping Subsystem (EDS) which performs controls calculations; and the Remote Interface Unit (RIU) which is used for data acquisition, transmission, and filtering. The flight-like RIU is the interface between the EDS and the sensors and actuators positioned on the particular structure under control. The EDS and RIU communicate over the MIL-STD-1553B, a space flight qualified bus. To test the CCS under realistic conditions, it was connected to the Phase-0 CSI Evolutionary Model (CEM) at NASA Langley Research Center. The following schematic shows how the CCS is connected to the CEM. Various tests were performed which validated the ability of the system to perform control/structures experiments.

  19. Geoacoustic and source tracking using particle filtering: experimental results.

    PubMed

    Yardim, Caglar; Gerstoft, Peter; Hodgkiss, William S

    2010-07-01

    A particle filtering (PF) approach is presented for performing sequential geoacoustic inversion of a complex ocean acoustic environment using a moving acoustic source. This approach treats both the environmental parameters [e.g., water column sound speed profile (SSP), water depth, sediment and bottom parameters] at the source location and the source parameters (e.g., source depth, range and speed) as unknown random variables that evolve as the source moves. This allows real-time updating of the environment and accurate tracking of the moving source. As a sequential Monte Carlo technique that operates on nonlinear systems with non-Gaussian probability densities, the PF is an ideal algorithm to perform tracking of environmental and source parameters, and their uncertainties via the evolving posterior probability densities. The approach is demonstrated on both simulated data in a shallow water environment with a sloping bottom and experimental data collected during the SWellEx-96 experiment. PMID:20649203

  20. 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.

  1. Uncalibrated Building Energy Simulation Modeling Results 

    E-print Network

    Ahmad, M.; Culp, C.H.

    2006-01-01

    to eighteen zones and found that for an internal-load-dominated building the effect of zon- ing was negligible. Her annual energy consumption results showed a difference of 3.5% between a one-zone and an eighteen-zone model. This result was obtained...- crepancy ranging from 85% to –98%. The whole building electricity consumption was within about ±10%. Table 3. Comparison of Modeled to Measured 1999 Annual Energy Consumption for WERC Table 4. Comparison of Modeled to Measured 2004 Annual Energy...

  2. Laser damage in triglycine sulfate: Experimental results and thermal analysis

    Microsoft Academic Search

    F. Bartoli; M. Kruer; L. Esterowitz; R. Allen

    1973-01-01

    An investigation of the effects of 10.6-?m laser radiation on triglycine-sulfate (TGS) crystals determined that the primary irreversible damage mechanisms in TGS pyroelectric detectors are cracking and thermal decomposition (charring). Irradiation thresholds for cracking and charring were determined for TGS crystals of typical detector dimensions as a function of laser power density and irradiation time. These energy density thresholds exhibit

  3. Experimental results on multi-charge-state lebt approach

    Microsoft Academic Search

    S. A. Kondrashev; A. Barcikowski; B. Mustapha; P. N. Ostroumov; R. H. Scott; S. I. Sharamentov; N. V. Vinogradov

    2007-01-01

    A multi-charge-state injector for a high-intensity heavy-ion linac is being developed at ANL. The injector consists of an all-permanent magnet ECR ion source [1], a 100 kV platform and a Low Energy Beam Transport (LEBT). The latter comprises two 60-degree bending magnets, electrostatic triplets and beam diagnostics stations. At present the injector system allows us to accelerate all ion species

  4. Experimental test results of a generalized parameter fuel control

    NASA Technical Reports Server (NTRS)

    Batterton, P. G.; Gold, H.

    1973-01-01

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

  5. 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.

  6. 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.

  7. Electrical characterization and experimental results in the SPEED4 plasma focus device

    NASA Astrophysics Data System (ADS)

    Zambra, Marcelo; Soto, Juan Carlos; Silva, Patricio; Sylvester, Gustavo; Pavez, Cristian; Moreno, Jose; Soto, Leopoldo

    2008-11-01

    The pulsed power SPEED4 generator has a capacitor bank system of 1,25 ?F in a Marx configuration to produce up to 100 kV, a maximum current up to ~700 kA, and 6,25 kJ of stored energy. In the plasma focus mode, this device has been prepared for the study of the emission of X-rays and neutrons in the Laboratory of Plasma Physics and Plasma Technologies of the Chilean Nuclear Energy Commission. The present experimental results report about the electrical characterization as well as preliminary results using Hydrogen like filling gas. Pinch evidences in the high voltage and current derivative electrical signals are presented in this work and preliminary arguments are given in order to achieve an optimal operation.

  8. Effects of Imperfect Dynamic Clamp: Computational and Experimental Results

    PubMed Central

    Bettencourt, Jonathan C.; Lillis, Kyle P.; White, John A.

    2008-01-01

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

  9. Experimental results of USSR nuclear explosion decoupling measurements

    SciTech Connect

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

    1992-09-01

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

  10. Experimental efforts and results in finding new heavy scintillators

    SciTech Connect

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

    1992-09-01

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

  11. 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.

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

    E-print Network

    Paris-Sud XI, Université de

    Broadband permeability measurement method for ferrites at any magnetization state: Experimental, i.e., the permittivity and the permeability. Unfortunately the experi- mental measurements November 2013) This paper describes the experimental results obtained by a broadband permeability

  13. Slip detection by tactile sensors: algorithms and experimental results

    Microsoft Academic Search

    E. G. M. Holweg; H. Hoeve; W. Jongkind; L. Marconi; C. Melchiorri; C. Bonivento

    1996-01-01

    Two techniques for slip detection with a rubber-based tactile matrix sensor are presented. The described results have been obtained within a common research activity between the Robotics and Automation Laboratory of the University of Bologna and the Control Laboratory of the Delft University of Technology. The first technique is based on a frequency analysis of the position of the center

  14. New experimental results on double beta decay of 130Te

    Microsoft Academic Search

    A. Alessandrello; C. Brofferio; O. Cremonesi; E. Fiorini; A. Giuliani; A. Nucciotti; M. Pavan; G. Pessina; S. Pirro; E. Previtali; M. Vanzini; L. Zanotti; C. Bucci; C. Pobes

    2000-01-01

    New results are presented of a search for double beta decay of Te isotopes carried out, using the bolometric technique, with an array of 20 natural tellurite crystals with a total cryogenic mass of ?6.8 kilograms. The array has been run at a temperature around 10 mK in the Gran Sasso Underground Laboratory. No evidence has been found for neutrinoless

  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. An Experimental Chip to Evaluate Test Techniques: Experiment Results

    Microsoft Academic Search

    Siyad C. Ma; Piero Franco; Edward J. Mccluskey

    1995-01-01

    This paper describes the testing of a chip especially designed to facilitate the evaluation of various test techniques for combinational circuitry. The different test sets and test conditions are described. Several tables show the results of voltage tests applied, either at rated speed or 2\\/3 speed, to each defective CUT. Data for CrossCheck, Very-Low-Voltage, IDDQ and delay tests are also

  17. 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.

  18. Experimental results of amplitude modulation reflectometry on the FTU tokamak

    SciTech Connect

    Zerbini, M.; Amadeo, P.; Buratti, P. [Associazione Euratom-ENEA sulla Fusione, Centro Ricerche Frascati, C.P. 65, 00044 Frascati, Roma (Italy)] [Associazione Euratom-ENEA sulla Fusione, Centro Ricerche Frascati, C.P. 65, 00044 Frascati, Roma (Italy)

    1997-01-01

    The amplitude modulation (AM) reflectometer realized for the FTU tokamak has been successfully operated in a wide range of plasma conditions. The reflectometer has been calibrated using the signal reflected by the inner part of the vacuum chamber (back wall) in absence of the plasma. Density profiles have been obtained for steady-state discharges by inverting the AM phase measured as a function of the carrier frequency. The results are in good agreement with density profiles obtained from multichannel far infrared interferometry. {copyright} {ital 1997 American Institute of Physics.}

  19. Experimental results of a propeller/wing interaction study

    NASA Technical Reports Server (NTRS)

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

    1991-01-01

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

  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. Time reversal of ultrasonic fields. Il. Experimental results.

    PubMed

    Wu, F; Thomas, J L; Fink, M

    1992-01-01

    For pt.I see ibid., vol.39, no.5, p.555-66 (1992). A time-reversal mirror (TRM) is made of an array of transmit-receive transducers. The incident pressure field is sampled, digitized, stored, time-reversed and then re-emitted. This process can be used to focus, through inhomogeneous media, on a reflective target that may behave as an acoustic source after being insonified TRM experiments using a 64-channel prototype are described, and the results are given. Focusing experiments conducted on point targets through different aberrating media are described. The major result shows that the time-reversal focusing technique compensates for all the distortions whatever the TRM-aberrator distance. When the medium contains several targets, the authors show that the time-reversal process can be iterated in order to focus on the most reflective one. Lithotripsy applications are also discussed. Kidney stones are spatially extended targets and TRM experiments have been conducted on several kidney stones located behind inhomogeneous media. They show that the iterative TRM process is able to select one of the kidney stones and to focus on a small portion of it. PMID:18267668

  2. 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

  3. Correlation between analytical and experimental results for propagation buckling

    SciTech Connect

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

    1996-12-01

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

  4. DARWIN fringe sensor: experimental results on the BRISE bench

    NASA Astrophysics Data System (ADS)

    Mocœur, Isabelle; Cassaing, Frédéric; Baron, Fabien; Mugnier, Laurent; Hofer, Stephan; Thiele, Hans

    2006-06-01

    Interferometer performances are linked to the measurement and the correction of telescope aberrations. For cophasing the large number of beams required by the DARWIN mission with the specified requirements (realtime piston/tip/tilt correction and measurement of higher orders up to spherical aberration), focal-plane approach has been selected due to its simple opto-mechanical device. Several focal-plane algorithms, developed at ONERA and gathered in the stand-alone MASTIC tool, were validated by experiment with a dedicated breadboard on the laboratory test bench BRISE. Our study shows the correct behaviour of the algorithms for linearity and repeatability; specific requirements are reached for piston/tip/tilt and higher order aberrations. These results confirm the validity of focal-plane sensors for the cophasing of multiple-aperture telescopes.

  5. 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.

  6. Wide-field Fizeau imaging telescope: experimental results.

    PubMed

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

    2006-06-20

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

  7. Experimental Results on Statistical Approaches to Page Replacement Policies

    SciTech Connect

    LEUNG,VITUS J.; IRANI,SANDY

    2000-12-08

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

  8. 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.

  9. On the probability distribution of the experimental results

    E-print Network

    A. P. Bukhvostov

    1997-05-22

    The analysis of Tables of particle properties shows that the probability distribution of the results of physical measurements is far from the conventional Gaussian $\\rho(\\xi)=exp(-\\xi^2/2) $, but is more likely to follow the simple exponential law $\\rho(\\xi)=exp(-\\xi)$ ($\\xi$ is the deviation of the measured from the true value in units of the presented standard error). A gap between the expected and actual probabilities grows with $\\xi$ very rapidly, amounting to $ 10^7 $ at $\\xi\\approx 6 $, and is significant even at $\\xi=2 $. A more detailed study reveals the two-component structure of the distribution: the $exp(-\\xi)$ law is closely fulfilled up to $\\xi=3$, but then, at $\\xi$ larger than that, the decrease is retarded drastically. This behaviour can be associated with the existence of two various types of systematic errors, the detected and undetected ones. Within some model, both types of errors are seen to affect the form of the distribution, one at moderate $\\xi$ and the other at large $\\xi$. The first type (detected) errors are shown in some natural-looking assumptions to yield the distribution not quite equal but close to the simple exponential.

  10. The experimental results and analysis of a borehole radar prototype

    NASA Astrophysics Data System (ADS)

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

    2012-04-01

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

  11. Dislocability of Localization Devices for Nonpalpable Breast Lesions: Experimental Results

    PubMed Central

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

    2014-01-01

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

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

    SciTech Connect

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

    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.

  13. 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.

  14. 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.

  15. Energy Monitoring--Objectives vs Results

    E-print Network

    McEver, R. M. Jr.

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

  16. Some experimental results for the head\\/hand effects in personal communications

    Microsoft Academic Search

    A. G. Neto; N. Nogueiru de Carvalho; J. da Costa e Silva

    1997-01-01

    In this work, some experimental results for the head\\/hand effects in personal communications are presented, for the real situation of a person during a call in the AMPS system. The hand-held unit has a monopole antenna. A simple measurement procedure is described and experimental results are discussed including biological effect aspects and wireless communication system performance. The obtained results will

  17. Experimental study and first clinical results with a cooled applicator system for interstitial laser coagulation (LITT)

    NASA Astrophysics Data System (ADS)

    Roggan, Andre; Knappe, Verena; Mack, Martin G.; Vogl, Thomas J.; Albrecht, Dirk; Germer, Christoph-Thomas; Ritz, Joerg-Peter; Kniep, F.; Mueller, Gerhard J.

    1998-04-01

    Laser-induced interstitial thermotherapy has proven to be an effective method for the treatment of different types of tumors. Until now the attainable coagulation volume was limited by the maximum applicable energy. The limiting factor was the high tissue temperature around the applicator which may have caused applicator damage. Consequently an internally cooled catheter system has been developed in order to reduce the temperature of the applicator surface and to allow for the application of higher laser powers. The optimal treatment parameters for the Nd:YAG laser were determined on the basis of in vitro studies with porcine tissue. Following these experimental studies, 127 patients with liver metastases were treated with the cooled system. The applicator position and the resulting tissue damage were verified using a MRI on-line monitoring system applying a FLASH-2D sequence. The optimal in vivo treatment parameters were found to be 25 watts for an exposure time of 20 minutes, resulting in coagulated volumes of up to 20 cm3. The experimental and clinical results have proven that the combination of a scattering laser applicator with an internally flushed catheter enables a significant increase in the coagulation volume.

  18. Experimental study and first clinical results with a cooled applicator system for LITT

    NASA Astrophysics Data System (ADS)

    Knappe, Verena; Roggan, Andre; Mack, Martin G.; Vogl, Thomas J.; Albrecht, Dirk; Germer, Christoph-Thomas; Kniep, F.; Mueller, Gerhard J.

    1998-01-01

    Laser-induced interstitial thermotherapy has proven to be an effective method for the treatment of different types of tumors. Until now the attainable coagulation volume was limited by the maximum applicable energy. The limiting factor is the high tissue temperatures around the applicator which may cause applicator damage. Consequently an internally cooled catheter system has been developed in order to reduce the temperature of the applicator surface and therefore enable the application of higher laser powers. The optimal treatment parameters for the Nd:YAG laser were determined on the basis of computer simulations and in vitro studies with porcine liver. Following these experimental studies, 72 patients with liver metastases were treated with the cooled applicator system. The applicator position and the resulting tissue damage were verified using the MRI on- line monitoring system with a FLASH-2D sequence. The optimal treatment parameters were found to be 25 watts for an exposure time of 20 minutes, resulting in coagulated volumes of up to 20 cm3. The experimental and clinical results proved that the combination of a scattering laser applicator with an internally flushed catheter enables a significant increase in the coagulation volume.

  19. Experimental Studies of Elementary Particle Interactions at High Energies

    SciTech Connect

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

    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.

  20. Results from STAR Beam Energy Scan Program

    E-print Network

    Michal Sumbera

    2013-01-31

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

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

    Microsoft Academic Search

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

    1988-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    1988-10-01

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

  3. Experimental Results of Single Carrier Digital Modulation for Underwater Sensor Networks

    Microsoft Academic Search

    Se-Young Kim; Jeong-woo Han; Ki-Man Kim; Sang-hoon Baek; Hyung-chul Kim; Chang-hwa Kim

    2010-01-01

    This paper presents the experimental results of single carrier digital modulation schemes for underwater sensor networks. To obtain a real sea data of acoustic communications, an experiment was performed at the shallow water environments. ASK and FSK were used as non-coherent modulation scheme and QPSK and 16-QAM are used as coherent modulation scheme. Except for 16 QAM, the experimental results

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

    E-print Network

    Jesus, Sérgio M.

    Geometric and Seabed parameter estimation using a Vector Sensor Array - Experimental results from and depth, as well as seabed parameters. The objective of this paper is to present experimental results for geometric (range and depth) and seabed geoacoustic parameter estimation (sediment compressional speed

  5. Energy harvester for vehicle tires: Nonlinear dynamics and experimental outcomes

    Microsoft Academic Search

    Stefano Tornincasa; Maurizio Repetto; Elvio Bonisoli; Francesco Di Monaco

    2012-01-01

    This article presents a very compact electromechanical wideband energy harvester optimized for tire applications. The device exploits an asymmetric magnetic spring to be adaptive and effective at almost any vehicle speed. The device has been simulated through an experimentally validated SIMULINK block-oriented model. The simulation takes into account nonlinear dynamic and adaptive resonant behavior of the seismic mass, electromagnetic, and

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

    Microsoft Academic Search

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

    1998-01-01

    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

  7. Simulation results and experimental design for the microwave inverse FEL accelerator

    SciTech Connect

    Yoder, R.B. [Physics Dept., Yale University, New Haven, Connecticut (United States) 06520-8120; Zhang, T.B. [Omega-P, Inc., 202008 Yale Station, New Haven, Connecticut (United States) 06520-2008; Marshall, T.C. [Dept. of Applied Physics, Columbia University, New York, New York (United States) 10027; Hirshfield, J.L. [Physics Dept., Yale University, New Haven, Connecticut (United States) 06520-8120

    1997-03-01

    A microwave inverse free-electron-laser accelerator (MIFELA) is currently under construction at the Yale Beam Physics Laboratory. MIFELA is an accelerator based on stimulated absorption of microwave energy by electrons moving in a magnetic wiggler field and axial guiding field; both fields are tapered to maintain near-resonance during acceleration. The acceleration structure is a simple, smooth-bore cavity, surrounded by a bifilar helical wiggler. A 2-1/2 cell RF gun provides 5 ps bunches of 6 MeV electrons, and {approximately}4MW of RF energy at 11.4 GHz is taken from the output of the Yale gyroharmonic converter. 3D simulation results are presented for electron acceleration from 6 to 11 MeV in 1.5 m, which show a high trapping fraction (78{percent}) and a final FWHM energy spread of 0.9{percent}. Details of the experimental parameters and current design issues are discussed. {copyright} {ital 1997 American Institute of Physics.}

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

    SciTech Connect

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

    2005-05-24

    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.

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

    Microsoft Academic Search

    Qiuya Ni; Jianzhong Tong; Yuanlong Kan; Jun Wang; Yuzen Cui

    1997-01-01

    The R&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

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

    Microsoft Academic Search

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

    2001-01-01

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

  11. 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

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

    NASA Astrophysics Data System (ADS)

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

    2015-01-01

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

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

    SciTech Connect

    Adriaenssens, G.J.; Arkhipov, V.I. [Katholieke Univ. Leuven, Heverlee-Leuven (Belgium). Lab. voor Halfgeleiderfysica

    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.

  14. Surface roughening and unstable neck formation in faceted particles. 1: Experimental results and mechanisms

    SciTech Connect

    Rankin, J.; Sheldon, B.W. (Brown Univ., Providence, RI (United States). Div. of Engineering)

    1999-07-01

    Experimental in situ TEM results described by Rankin and Boatner are surprising because they show initial neck formation between two isolated MgO particles, followed by neck rupture. A quantitative assessment of the original images shows that initial neck growth corresponds to material removed from the rounded edges which contact the neck, and that neck rupture transfers material directly from the neck to the adjacent faceted faces. During the initial neck growth process surface diffusion along the rounded edges of the crystals is apparently the dominant mass transport mechanism, and material is not transferred to the faceted faces because of the energy barrier associated with forming a new atomic layer on top of a faceted surface. This energy barrier can apparently be overcome when a curvature reversal at a facet/rough surface boundary creates a step which makes it possible to add one or more new atomic layers to the faceted face(s). This can move material away from the neck, and thus lead to neck rupture.

  15. Electron and positron energy spectra: HEAT magnet spectrometer results

    NASA Astrophysics Data System (ADS)

    Duvernois, M. A.

    1999-08-01

    Observations of the cosmic ray electron and positron spectra have been carried out with a balloon-based detector, the "High-Energy Antimatter Telescope" (HEAT), flown in May 1994 from Fort Sumner, NM and August 1995 from Lynn Lake, Manitoba. We present a summary of the instrument procedures and data analysis as well as electron and positron measurements. The electron and positron spectra results from the Lynn Lake flight are presented here for the first time and are combined with the previously-reported Fort Sumner data. These measurements have provided new determinations of the energy spectra of electrons from 1-100 GeV and positrons from 1-50 GeV. Within the experimental uncertainties, the intensity of positrons is consistent with a purely secondary origin, due to nuclear interactions in interstellar space.

  16. Coupled helicopter rotor/body aeromechanical stability comparison of theoretical and experimental results

    NASA Technical Reports Server (NTRS)

    Friedmann, P. P.; Venkatesan, C.

    1985-01-01

    This paper presents the results of an analytical study aimed at predicting the aeromechanical stability of a helicopter in ground resonance, with the inclusions of aerodynamic forces. The theoretical results are found to be in good agreement with the experimental results, available in the literature, indicating that the coupled rotor/fuselage system can be represented by a reasonably simple mathmatical model.

  17. Comparison of experimental coupled helicopter rotor/body stability results with a simple analytical model

    NASA Technical Reports Server (NTRS)

    Friedmann, P. P.; Venkatesan, C.

    1988-01-01

    The results of an analytical study aimed at predicting the aeromechanical stability of a helicopter in ground resonance, with the inclusion of aerodynamic forces are presented. The theoretical results are found to be in good agreement with the experimental results, available in literature, indicating that the coupled rotor/fuselage system can be represented by a reasonably simple mathematical model.

  18. Two-Factor Authentication or How to Potentially Counterfeit Experimental Results in

    E-print Network

    Uhl, Andreas

    Two-Factor Authentication or How to Potentially Counterfeit Experimental Results in Biometric to a growing in- terest in biometrics. As a result several two-factor authentication systems are designed to include biometric authentication. In this work the risk of result distortion during performance evalua

  19. 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.

  20. A Summary of Experimental Results on Molecular Hydrogen Formation on Dust Grain Analogues

    NASA Astrophysics Data System (ADS)

    Vidali, Gianfranco; Roser, J. E.; Manicó, G.; Pirronello, V.

    We review the main laboratory results of investigations of processes of molecular hydrogen formation on surfaces. The problem of the formation of molecular hydrogen is a fundamental issue in astrophysics/astrochemistry, because of the great importance that molecular hydrogen has for the structure and evolution of our Universe. Such experiments are done using ultra-high vacuum, low temperature, and atomic/molecular beam techniques to study the formation of molecular hydrogen on dust grain analogues in conditions as close as technically feasible to the ones present in relevant ISM environments. In experiments conducted at Syracuse University, we studied H2 formation on the three most ISM-relevant classes of surfaces: silicates, carbonaceous materials and amorphous water ice. Our experimental investigations range from the evaluation of the catalytic efficiency of the studied surfaces to the energetics of the reaction, i.e. the partition of the formation energy between the grain and the nascent molecule. Such measurements have been done by changing various parameters such as: the temperature of the interstellar dust analogue, the kinetic temperature of the atoms, the morphology of the surface and, to be completed soon, the composition of the solid. Quantitative and qualitative information on the processes of H2 formation is then fed in theoretical models to extract results that pertain to desired ISM environments.

  1. Experimental investigation of the collapse modes and energy absorption characteristics of composite tubes

    Microsoft Academic Search

    Chiara Bisagni

    2009-01-01

    This paper describes the results of an experimental investigation of tubes made of different composite materials. They are structural components used in the aerospace and automotive industries, which are able to absorb large amounts of impact energy while collapsing progressively in a controlled manner. Because of the complex fracture mechanisms, several different collapse modes are obtained. From the tests, it

  2. An experimental study of thermal energy storage with phase change materials by design of experiments

    Microsoft Academic Search

    Belen Zalba; Belen Sanchez-valverde; Jose Marin

    2005-01-01

    Accurate theoretical modelling and simulation of thermal energy storage (TES) by means of phase change materials (PCM) is very complex and its results are not close enough to experimental values. This paper presents the empirical study of a thermal storage unit operating with a commercial PCM called RT25. The study is carried out by means of the statistical procedure, Design

  3. A propulsion-oriented synthesis of the antiproton-nucleon annihilation experimental results

    Microsoft Academic Search

    G. Vulpetti

    1984-01-01

    The antiproton-proton and antiproton-neutron annihilation processes are reviewed in the light of recent experimental investigations. This paper is aimed at stressing those features that could be among the fundamental ones in conceiving an antimatter-matter powered spacecraft. Annihilation product mean-energy versus time diagrams are made for propulsion analysis purposes.

  4. Delamination behavior of spliced Fiber Metal Laminates. Part 1. Experimental results

    Microsoft Academic Search

    T. J. de Vries; A. Vlot; F. Hashagen

    1999-01-01

    The sizes of Fiber Metal Laminate (FML) sheets available can be increased considerably with the application of the splicing concept. A disadvantage of this concept can be the occurrence of delamination caused by load transfer over the splice. An experimental program has been carried out to investigate the delamination behavior for different splicing geometries and metal layer thicknesses. Griffith's energy

  5. 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. [Los Alamos National Laboratory, P.O. Box 1663, MS E526, Los Alamos, New Mexico 87545 (United States)] (and others)

    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.

  6. Total electronic energy by tight binding approximation and experimental toughness of three different hybrid polymers

    Microsoft Academic Search

    N. Olivi-Tran; A. Ferchichi; S. Calas; P. Etienne

    2008-01-01

    We computed by a modified tight binding approximation, the total electronic energy of three different hybrid polymers: $H-SiO_2$, $CH_3-SiO_2$ and $C_6H_5-SiO_2$. We made the hypothesis that the structures of these polymers are amorphous. Computational results regarding the total electronic energy and experimental data \\\\cite{ferchichi} on the toughness of these three hybrid polymers were compared. A good qualitative agreement was found

  7. 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…

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

    NASA Technical Reports Server (NTRS)

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

    1994-01-01

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

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

    NASA Technical Reports Server (NTRS)

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

    1993-01-01

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

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

    SciTech Connect

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

    1998-10-01

    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.

  11. Experimental results from internal odometry error correction with the OmniMate mobile robot

    Microsoft Academic Search

    Johann Borenstein

    1998-01-01

    This paper presents the experimental results of test with a new method for detecting and correcting odometry errors without inertial or external-reference sensors. This method, called internal position error correction (IPEC), has been implemented on a new, commercially available mobile robot called “OmniMate”, which was specifically designed for the implementation of the IPEC method. The results presented show that the

  12. Experimental results on design aspects of a compact repetitive Marx generator

    Microsoft Academic Search

    Archana Sharma; V. Sharma; D. D. P. Kumar; S. Mitra; K. Senthil; K. V. Nagesh; D. P. Chakravarthy; A. K. Ray

    2009-01-01

    This paper presents the experimental results of a repetitive Marx generator being developed at BARC. Effect of lead inductance, sparkgaps' alignment, charging inductor, ground inductor and shielding has been studied. Two types of configurations have been adopted in order to reduce the erected Marx inductance and results are compared. In this Marx generator plus-minus charging scheme was adopted for both

  13. Calculation of Impedance from Multibunch Synchronous Phases: Theory and Experimental Results

    SciTech Connect

    Prabhakar, Shyam

    1998-10-20

    A novel beam-based method for measuring the longitudinal impedance spectrum is demonstrated using experimental data from the PEP-II High Energy Ring (HER). The method uses a digital longitudinal feedback system from which the charge and synchronous phase are measured for every bucket. Calculation of the transfer function from fill shape to synchronous phase yields the impedance seen by the beam at revolution harmonics. The experimentally-derived longitudinal impedance function and lab measurements of the impedance of parked RF cavities are compared to suggest a mechanism for the occasional instability of low-order coupled bunch modes observed in the HER during commissioning in October 1997.

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

    NASA Technical Reports Server (NTRS)

    Baker, Donald J.

    2004-01-01

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

  15. 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.

  16. Unified mechanistic concept of electrophilic aromatic nitration: convergence of computational results and experimental data.

    PubMed

    Esteves, Pierre M; De M Carneiro, José Walkimar; Cardoso, Sheila P; Barbosa, André G H; Laali, Kenneth K; Rasul, Golam; Prakash, G K Surya; Olah, George A

    2003-04-23

    The mechanism of electrophilic aromatic nitration was revisited. Based on the available experimental data and new high-level quantum chemical calculations, a modification of the previous reaction mechanism is proposed involving three separate intermediates on the potential energy diagram of the reaction. The first, originally considered an unoriented pi-complex or electron donor acceptor complex (EDA), involves high electrostatic and charge-transfer interactions between the nitronium ion and the pi-aromatics. It explains the observed low substrate selectivity in nitration with nitronium salts while maintaining high positional selectivity, as well as observed oxygen transfer reactions in the gas phase. The subsequent second intermediate originally considered an oriented "pi-complex" is now best represented by an intimate radical cation-molecule pair, C(6)H(6)(+)(*)()/NO(2), that is, a SET complex, indicative of single-electron transfer from the aromatic pi-system to NO(2)(+). Subsequently, it collapses to afford the final sigma-complex intermediate, that is, an arenium ion. The proposed three discrete intermediates in electrophilic aromatic nitration unify previous mechanistic proposals and also contribute to a better understanding of this fundamentally important reaction. The previously obtained ICR data of oxygen transfer from NO(2)(+) to the aromatic ring are also accommodated by the proposed mechanism. The most stable intermediate of this reaction on its potential energy surface is a complex between phenol and NO(+). The phenol.NO(+) complex decomposes affording C(6)H(6)O(+)(*)/PhOH(+) and NO, in agreement with the ICR results. PMID:12696903

  17. Automated modular high energy evaluation system for experimental thyristor devices

    NASA Astrophysics Data System (ADS)

    Lacouture, Shelby; Lawson, Kevin; Bayne, Stephen; Giesselmann, Michael; Scozzie, Charles J.; O'Brien, Heather; Ogunniyi, Aderinto A.

    2013-10-01

    A high energy, modular, completely automated test bed with integrated data acquisition and characterization systems was successfully designed in order to perform both safe operating area as well as very high volume reliability testing on experimental silicon carbide Super Gate Turn Off (SGTO) thyristors. Although the system follows a modular design philosophy, with each functional block acting as a peripheral to a main control module and can be adapted to arbitrary power and pulse width levels, for the specific SGTO devices initially evaluated it was configured to have the device discharge variable current levels of up to 6 kA into a 0.5 ? resistive load with a relatively square pulse fixed at 100 ?s full width at half maximum delivering energy levels up to 1.8 kJ to the load.

  18. 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.

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

    NASA Technical Reports Server (NTRS)

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

    1985-01-01

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

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

    NASA Astrophysics Data System (ADS)

    Mijatovic, Nenad; Jensen, Bogi Bech

    2014-05-01

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

  1. 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.

  2. A Self-Sensing Homopolar Magnetic Bearing: Analysis and Experimental Results

    E-print Network

    Sanders, Seth

    A Self-Sensing Homopolar Magnetic Bearing: Analysis and Experimental Results Perry Tsao Seth R bearing is designing a suitable position sensor. A ho- mopolar magnetic bearing that uses the same coils to stabilize the rotor and sense its position is introduced. A prototype bearing has been built

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

    Microsoft Academic Search

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

    2010-01-01

    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

  4. Experimental results on adaptive output feedback control using a laboratory model helicopter

    Microsoft Academic Search

    Ali T. Kutay; Anthony J. Calise; Moshe Idan; Naira Hovakimyan

    2005-01-01

    Experimental results are presented that illustrate a recently developed method for adaptive output feedback control. The method permits adaptation to both parametric uncertainty and unmodeled dynamics, and incorporates a novel approach that permits adaptation under known actuator characteristics including actuator dynamics and saturation. Only knowledge of the relative degree of the controlled system within the bandwidth of the control design

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

    E-print Network

    Oak Ridge National Laboratory

    #12;GROUND-COUPLED HEAT-PUMP-SYSTEM EXPERIMENTAL RESULTS* Philip D. Metz _Solar and Renewables house in Upton, Long Island, New York has been heated and cooled by a liquid source heat pump using- saving construction with a heating load of 7.8 X 106 J/OC-day (4.1 X 103 Btu/ OF-day). The heat pump used

  6. Experimental results on the free cooling power available on 4K pulse tube coolers

    E-print Network

    Boyer, Edmond

    Experimental results on the free cooling power available on 4K pulse tube coolers T Prouv´e1, H on the free cooling power available at the level of the second stage regenerator of a 4K pulse tube cooler and the pulse tube stages under different distributions of the total heat load. 1. Introduction In order

  7. Colour Rendering of Polymer Network Cholesteric Liquid Crystal: Model and Experimental Results

    Microsoft Academic Search

    P. Sixou; J. Nourry; H. Guillard; C. Gautier

    2001-01-01

    We present a model of the colour rendering of the Cholesteric Polymer Network Liquid Crystal and a comparison with experimental results. The active medium was considered as a pile of stacked layers with continuous variable optical properties. The computation considers the optics of stratified mediums (matrix formalism) and in the complementary case analytical spectra were computed using theory of cholesterics.

  8. Linear viscous fingering: New experimental results, direct simulation and the evaluation of averaged models

    Microsoft Academic Search

    K. S. Sorbie; H. R. Zhang; N. B. Tsibuklis

    1995-01-01

    In this paper, miscible viscous fingering results have been presented for almost homogeneous “two-dimensional linear” (relatively long and narrow) displacement experiments at mobility ratios of approximately M = 4, 11 and 30. Both effluent profiles (recoveries) and pressure drops along the fingers have been measured and the reproducibility of these in each of the experimental cycles in repacked beds is

  9. 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.

  10. Changing forest water yields in response to climate warming: results from long-term experimental watershed

    E-print Network

    Changing forest water yields in response to climate warming: results from long-term experimental, ON N6A 5B7, Canada, 2 Department of Geography, College of Earth, Ocean, and Atmospheric Sciences Bank Drive, Peterborough, ON K9J 7B8, Canada, 4 USDA Forest Service, NRS, P.O. Box 404, Parsons, WV

  11. This paper presents design, fabrication, and experimental results of a wireless induction heating

    E-print Network

    ABSTRACT This paper presents design, fabrication, and experimental results of a wireless induction magnetic excitation using a coil, and applied to an in-vitro skin ablation experiment. The experiment has gradient across the stratum corneum, so that deeper viable tissues are not heated. In this way

  12. Towards the additional use of phase processing in multistatic FMCW radar, considerations and experimental results

    Microsoft Academic Search

    P. J. F. Swart; H. T. Steenstra; F. L. Muller; W. F. van der Zwan; P. van Genderen; L. P. Ligthart; G. L. Reijns; A. J. C. van Gemund

    1999-01-01

    A multistatic FMCW radar system is being developed to serve as an obstacle warning and 2D\\/3D- location sensor on autonomous vehicles. In this paper the additional use of available phase data is considered and some recently obtained experimental results are introduced.

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

    E-print Network

    Paris-Sud XI, Université de

    Distant Speech Recognition for Home Automation: Preliminary Experimental Results in a Smart Home speech conditions was 7.5% CER. Keywords-component; distant speech recognition; keyword detection still need to be overcome in these environments including robust distant speech recognition in noisy

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

    Microsoft Academic Search

    Yang Yang; William W. Liou

    2011-01-01

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

  15. Life prediction techniques for variable amplitude multiaxial fatigue. Part 2: Comparison with experimental results

    Microsoft Academic Search

    C. H. Wang; M. W. Brown

    1996-01-01

    An extensive multiaxial random fatigue test program was conducted at room temperature using tubular specimens. Experiments were performed under combined tension\\/torsion and triaxial loading, covering proportional and nonproportional variable amplitude loading cases. The two proposed life prediction methods discussed in Part 1 are evaluated using the experimental results, demonstrating that these two methods provide satisfactory predictions.

  16. MTF simulation including transmittance effects and experimental results of charge-coupled imagers

    Microsoft Academic Search

    SAVVAS G. CHAMBERLAIN; DAVID H. HARPER

    1978-01-01

    A modulation transfer function (MTF) model for front-illuminated charge-coupled imagers (CCI's) which takes into account the periodically varying light transmittance of the photoelement array surface is derived. An inexpensive direct MTF measurement technique for CCI's was developed and is described. Experimental MTF measurements confirm the complete MTF model. Spatial resolution measurements and MTF simulation results of practical CCI photoelement array

  17. Program LESSA (Lineament Extraction and Stripe Statistical Analysis) automated linear image features analysis—experimental results

    NASA Astrophysics Data System (ADS)

    Zlatopolsky, Alexandre A.

    1992-10-01

    The LESSA program for automated linear image features extraction and analysis is presented. The main experimental results of LESSA testing and of its application to aerial and satellite imagery processing are discussed. It is shown that the description of texture orientation properties obtained reflects the image pattern and scarcely depends on applied procedures and their parameters.

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

    E-print Network

    Barber, James R.

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

  19. Wave synchronizing crane control during water entry in offshore moonpool operations - experimental results

    Microsoft Academic Search

    Tor A. Johansen; Thor I. Fossen; Svein I. Sagatun; Finn G. Nielsen

    2003-01-01

    A new strategy for active control in heavy-lift offshore crane operations is suggested by introducing a new concept referred to as wave synchronization. Wave synchronization reduces the hydrodynamic forces by minimizing variations in the relative vertical velocity between payload and water using a wave-amplitude measurement. Wave synchronization is combined with conventional active heave compensation to obtain accurate control. Experimental results

  20. EXPERIMENTAL RESULTS OF A PLASMA WAKEFIELD ACCELERATOR USING MULTIPLE ELECTRON BUNCHES

    E-print Network

    Brookhaven National Laboratory

    EXPERIMENTAL RESULTS OF A PLASMA WAKEFIELD ACCELERATOR USING MULTIPLE ELECTRON BUNCHES E. Kallos, T bunches in order to drive a plasma wave. The experiments were performed at the Accelerator Test Facility of Brookhaven National Laboratory where 5 8 equidistant bunches with a spacing that was varied between 100 250 m

  1. Phase modulation of a ring-laser gyro--Part II: Experimental results

    Microsoft Academic Search

    S. Wax; M. Chodorow

    1972-01-01

    Experimental results are presented for the multimode ring-laser gyro with intracavity phase modulation. By proper choice of modulator frequency, the oppositely directed traveling waves (ODTW) exist as either pulse trains or FM signals. Conditions have been achieved, depending upon the time at which pulses arrive at the modulator, in which lock in between ODTW does not occur at low rotation

  2. Experimental Results of Cross-Site Exchange of Web Content Anomaly Detector Alerts

    E-print Network

    Yang, Junfeng

    Experimental Results of Cross-Site Exchange of Web Content Anomaly Detector Alerts Nathaniel Boggs1-day and polymorphic attacks pose a critical widespread threat to web servers. Network-based Anomaly Detection (AD false alarms. For instance, see shadow servers in [1]. We propose a large scale network of AD sensors

  3. 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.

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

    Microsoft Academic Search

    Lauro Ojeda; Giulio Reina; Johann Borenstein

    2004-01-01

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

  5. Experimental Results on the Synthesis of Petri Nets from Partial Robin Bergenthum, Sebastian Mauser

    E-print Network

    Desel, Jörg

    Experimental Results on the Synthesis of Petri Nets from Partial Languages Robin Bergenthum algorithm for place/transition-nets from finite partial languages was developed. In this paper we present of Petri nets from behavioural descriptions has been a successful line of research since the 1990s

  6. 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 Kung13 9PL, United Kingdom kung-kiu,zw@cs.man.ac.uk ABSTRACT SPARK is useful for developing reliable components in SPARK and use existing SPARK tools to produce verified component-based software. We demon

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

    Microsoft Academic Search

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

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

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

    E-print Network

    Boyer, Edmond

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

  10. Experimental investigation of the energy and temperature dependence of beryllium self sputtering

    SciTech Connect

    Korshunov, S.N.; Guseva, M.I.; Stolijarova, V.G. [RRC Kurchatov Institute, Moscow (Russian Federation)

    1995-09-01

    The low-Z metal beryllium is considered as plasma facing material (PFM) for the ITER. It is expected that operation temperature range of beryllium PFM will be (670 - 1070) K. While experimental Be-sputtering data bases exist for H{sup +}, D{sup +} and He{sup +}-ions, the self-sputtering yields of Be have only been estimated by computer simulation. In this paper we report the experimental results on the energy and temperature dependence of the beryllium self-sputtering yield (S). The energy dependence of S{sup s} in the energy range (0.5 - 10.0) keV was measured at 670 K. The self-sputtering yield of Be attains its maximal value at the ion energy of 1.5 keV, being equal to 0.32 {+-} at./ion. Comparison of the experimental results and theoretical prediction shows a good agreement for energy dependence of S{sup s}. The temperature dependence of S{sup s} in the temperature range (370-1070)K was obtained for 0.9keV Be{sup +}-ions. The value of S{sup s} is not changed up to 870 K. It sharply increases at the temperatures above 870 attaining the value of 0.75 at./ion at 1070 K.

  11. China Energy Efficiency Round Robin Testing Results for Room

    E-print Network

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

  12. Structure of downward spreading flames: a comparison of numerical simulation, experimental results and a simplified parabolic theory

    NASA Astrophysics Data System (ADS)

    Bhattacharjee, Subrata; King, Matthew D.; Paolini, Chris

    2004-03-01

    Temperature and velocity fields in a downward flame spread over flat, solid fuels in a gravitational field are numerically simulated and compared with available experimental measurements and a simplified theory. The two-dimensional steady numerical model solves the mass, energy, species-mass, and momentum equations in the gaseous phase and the energy equation in the solid phase and includes gas-phase and pyrolysis kinetics, gas and surface radiation with radiation feedback. The published experimental results include measured temperature and velocity profiles, surface regression data, visible images of flames, and images taken with interferometers. A simplified parabolic solution for the temperature field in an opposed-flow configuration is extended to the downward configuration and compared with the simulation and experimental results. Flames over thin cellulosic fuels and PMMA, both in the thick and thin limits are considered. With one exception, the numerical model is found to reproduce the observed flame structure for a diverse range of fuel and ambient conditions. The simplified theory, based on a parabolic solution of the coupling functions, is found to reproduce the temperature fields in the gas and the solid reasonably well for flame spreads over thick fuels. EHPRG Award Lecture.

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

    SciTech Connect

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

    1984-09-01

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

  14. A comparison of experimental and theoretical results for labyrinth gas seals with honeycomb stators 

    E-print Network

    Hawkins, Lawrence Allen

    1988-01-01

    are compared to the coefficients of a labyrinth-rotor/smooth-stator seal having the same geometry. The coefficients are also compared to analytical results from a two-control-volume compressible ffow model. The experimental results show that the honeycomb... stator conffguration is more stable than the smooth stator conffguration 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...

  15. Experimental High Energy Physics Brandeis University Final Report

    SciTech Connect

    Blocker, Craig A. [Brandeis University] [Brandeis University; Bensinger, James [Brandeis University] [Brandeis University; Sciolla, Gabriella [Brandeis University] [Brandeis University; Wellenstein, Hermann [Brandeis University] [Brandeis University

    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.

  16. Design and Experimental Results for a Natural-Laminar-Flow Airfoil for General Aviation Applications

    NASA Technical Reports Server (NTRS)

    Somers, D. M.

    1981-01-01

    A natural-laminar-flow airfoil for general aviation applications, the NLF(1)-0416, was designed and analyzed theoretically and verified experimentally in the Langley Low-Turbulence Pressure Tunnel. The basic objective of combining the high maximum lift of the NASA low-speed airfoils with the low cruise drag of the NACA 6-series airfoils was achieved. The safety requirement that the maximum lift coefficient not be significantly affected with transition fixed near the leading edge was also met. Comparisons of the theoretical and experimental results show excellent agreement. Comparisons with other airfoils, both laminar flow and turbulent flow, confirm the achievement of the basic objective.

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

    NASA Technical Reports Server (NTRS)

    Somers, D. M.

    1981-01-01

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

  18. 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. [Chinese Academy of Sciences, Beijing (China). Inst. of Electrical Engineering

    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.

  19. New experimental results on the pion-nucleon interaction investigation in the resonance region

    NASA Astrophysics Data System (ADS)

    Sumachev, V. V.; Beloglazov, Yu. A.; Kovalev, A. I.; Kozlenko, N. G.; Kruglov, S. P.; Kulbardis, A. A.; Novinsky, D. V.; Trautman, V. Yu.; Alekseev, I. G.; Budkovsky, P. E.; Kanavets, V. P.; Koroleva, L. I.; Morozov, B. V.; Nesterov, V. M.; Ryltsov, V. V.; Sulimov, A. D.; Svirida, D. N.; Bazhanov, N. A.; Bunyatova, E. I.

    2002-03-01

    The spin rotation parameters A and R were measured for the elastic pion-proton scattering by the PNPI-ITEP collaboration in the D13 (1700), ?S31(1900), ?P33(1920) and ?D33 (1940) resonances region. These resonances were absent in the set of partial wave analysis (PWA) of the Virginia Polytechnic Institute group (VPI), but was included in the tables of the Review of Particle Physics. The main goal of the experimental program was to resolve the current PWA’s disagreement in spin rotation parameters value predictions. Simultaneously with A and R the polarization parameter P was measured with the purpose to improve the experimental data base and estimate the experimental systematic errors. Our results for spin rotation parameters A and | R| are in agreement with PWA VPI predictions.

  20. Extragalactic ultra high energy cosmic rays, II. Comparison with experimental data

    E-print Network

    Joerg P. Rachen; Todor Stanev; Peter L. Biermann

    1993-02-04

    We compare the expected contribution of FR-II hot spots to the ultra-high energy cosmic ray spectrum (Rachen & Biermann 1993, A&A in press, BB paper astro-ph/9301010) to improved experimental results. We introduce a "world data set" of UHE cosmic rays by comparing the data of various experiments, extracting relative systematic errors in the energy derivation and averaging over energy bins. Since the contribution of FR-II hot spots is expected to be dominated by protons, we can also compare it to the recent experimental results for the proton component of cosmic rays between 0.1 and 1 EeV from both the Fly's Eye and the Akeno airshower detector (Gaisser et al. 1993, Phys Rev D in press, and Stanev et al. 1992, A&A submitted). The result is striking: Our prediction for energies below 1 EeV fits very well to the data for the proton component, while explaining the total flux at highest energies as well. The result is consistent with the expectation of a galactic component, consisting of heavy nuclei only, that has a slope of about -3.1 and cuts off at 5 EeV, as predicted by Biermann 1993 (A&A in press, BB paper astro-ph/9301008)

  1. 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.

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

    NASA Astrophysics Data System (ADS)

    Goldhirsh, Julius; Vogel, Wolfhard J.

    1992-02-01

    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.

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

    SciTech Connect

    BURRELL,KH

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

  4. 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).

  5. 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.

  6. 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

  7. 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.

  8. Experimental method for the determination of the energy distribution of stress-induced oxide traps

    Microsoft Academic Search

    Alessandro S. Spinelli; Andrea L. Lacaita; Matteo Rigamonti; Gabriella Ghidini

    1999-01-01

    An experimental procedure for the determination of the energy distribution of oxide neutral traps is presented, showing the evolution of the stress-induced damage as a function of Fowler-Nordheim stress fluence and field. It is shown that the traps are mainly distributed around 2 eV from the oxide conduction band. Results are presented for different oxide technologies, investigating the effect of

  9. 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.

  10. 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.

  11. Spacecraft Power Beaming Using High-Energy Lasers, Experimental Validation

    SciTech Connect

    Michael, Sherif [Naval Postgraduate School ECE Dep./Space Systems Academic Group, Monterey, CA 93943 (United States)

    2008-04-28

    The lifetime of many spacecrafts are often limited by degradation of their electrical power subsystem, e.g. radiation-damaged solar arrays or failed batteries. Being able to beam power from terrestrial sites using high energy lasers, could alleviate this limitation, extending the lifetime of billions of dollars of satellite assets, as well as providing additional energy for electric propulsion that can be used for stationkeeping and orbital changes. In addition, extensive research at the Naval Postgraduate School (NPS) has shown the potential for annealing damaged solar cells using lasers. This paper describes that research and a proposed experiment to demonstrate the relevant concepts of high energy laser power beaming to an NPS-built and operated satellite. Preliminary results of ground experiment of laser illuminations of some of the solar panels of one of the spacecrafts are also presented.

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

    NASA Astrophysics Data System (ADS)

    Heinze, Thomas; Galvan, Boris; Miller, Stephen

    2013-04-01

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

  13. 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.

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

    SciTech Connect

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

    1993-05-01

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

  15. Room temperature thin foil SLIM-cut using an epoxy paste: experimental versus theoretical results

    NASA Astrophysics Data System (ADS)

    Bellanger, Pierre; Bouchard, Pierre-Olivier; Bernacki, Marc; Serra, Joao

    2015-04-01

    The stress induced lift-off method (SLIM) -cut technique allows the detachment of thin silicon foils using a stress inducing layer. In this work, results of SLIM-cut foils obtained using an epoxy stress inducing layer at room temperature are presented. Numerical analyses were performed in order to study and ascertain the important experimental parameters. The experimental and simulation results are in good agreement. Indeed, large area (5 × 5 cm2) foils were successfully detached at room temperature using an epoxy thickness of 900 ?m and a curing temperature of 150 °C. Moreover, three foils (5 × 3 cm2) with thickness 135, 121 and 110 ?m were detached from the same monocrystalline substrate. Effective minority carrier lifetimes of 46, 25 and 20 ?s were measured using quasi-steady-state photoconductance technique in these foils after iodine ethanol surface passivation.

  16. Analysis of very high frequency propagation in sediments: Experimental results and modeling

    NASA Astrophysics Data System (ADS)

    Brothers, Richard; Page, Sarah; Heald, Gary; Leighton, Tim; Simpson, Matt; Dix, Justin

    2002-11-01

    A current QinetiQ study is investigating the propagation of sound waves into sediment at frequencies higher than 300 kHz. Previous work has found notable discrepancies between model predictions and experimental results and comparisons are inconsistent and unreliable. This new work package investigates the development of new scattering theories for frequencies ranging from 300 kHz to 1 MHz. In particular, the application of a pseudospectral time difference approached is analyzed. The model originally developed for lower frequency applications, is set up in various geometrical scenarios and for varying very high frequencies. Results show the received simulated pulses obtained for hydrophones placed within the sediment and source colocated. Furthermore, simulations are compared in tank experimental data. The controlled tank experiments were conducted by Southampton University and data are analyzed and discussed for various conditions and frequencies.

  17. Experimental and analytical, transonic aerodynamic and acoustic results for rectangular and swept rotor blade tips

    NASA Astrophysics Data System (ADS)

    Prieur, J.; Lafon, P.; Caplot, M.; Desopper, A.

    This paper presents some experimental and theoretical studies dealing with both acoustics and aerodynamics of helicopter rotor blades in high-speed forward flight. Experimental results in S2Ch acoustically treated wind tunnel concern a comparison between a rectangular blade tip and a parabolic sweptback one, with an anhedral effect, named PF1. They show an increase in aerodynamic performances for the PF1 blades, which is due to a decrease of the transonic flow intensity on the advancing blade side. These results are confirmed by calculation with a transonic small disturbance code. Acoustic measurements show a noise reduction for the PF1 blades. This tendency appears also through calculation. An analytical study evaluates the influence of blade tip shape on the generated thickness noise. Assessment of compressibility effects by quadrupolar noise calculations for several blade tips is presented; the limitations of the use of the Lighthill's acoustic analogy are discussed.

  18. A preliminary analysis of the USML-1 drop dynamics experimental results

    NASA Technical Reports Server (NTRS)

    Wang, T. G.; Anilkumar, A. V.; Lee, C. P.; Lin, K. C.

    1993-01-01

    This is a quick-look report of the results of the drop dynamics experiments that were conducted in the Drop Physics Module aboard the United States Microgravity Laboratory (USML-1) Space Shuttle mission (STS 50) from June 25 to July 9, 1992. Two types of drop dynamics experiments namely: rotations of spherical drops and oscillations of simple and compound drops were studied. Preliminary results indicate that for the rotating liquid drop experiments, the experimental data agrees well with the theoretical (numerical) predictions in the axisymmetric and the two-lobed regions. The dynamics of the bifurcation point was studied, and it was found that the shift in the bifurcation point, due to drop deformation and due to spin-up and spin-down, coroborates the previous experimental data.

  19. Experimental Vibrational Zero-Point Energies: Diatomic Molecules Karl K. Irikuraa...

    E-print Network

    Magee, Joseph W.

    Experimental Vibrational Zero-Point Energies: Diatomic Molecules Karl K. Irikuraa... Physical online 18 April 2007 Vibrational zero-point energies ZPEs , as determined from published spectroscopic: molecular energetics; uncertainty; vibrational spectroscopy; zero-point energy. CONTENTS 1. Introduction

  20. Experimental and theoretical results for bending of a soft ferromagnetic plate in a transverse magnetic field

    Microsoft Academic Search

    K. Horiguchi; Y. Shindo

    2003-01-01

    Summary.  ?The results of an experimental and theoretical investigation of the bending behavior of a soft ferromagnetic cantilever beam-plate\\u000a in a transverse magnetic field are presented. The theoretical model based on a beam-plate theory for magneto-elastic interactions\\u000a in a soft ferromagnetic material predicts the deflection and strain for several values of the magnetic field and the geometrical\\u000a parameter. The experiments were

  1. Design, simulation, and experimental results of a 110 GHz high-power gyrotron mode converter

    Microsoft Academic Search

    D. R. Denison; M. Blank; T. S. Chu; B. Harper; J.-P. Hogge; K. E. Kreischer; J. A. Lorbeck; R. J. Temkin; R. J. Vernon

    1996-01-01

    Summary form only given. We present the design, computer simulation, and experimental results of a quasi-optical mode converter for use in a 110 GHz high-power gyrotron. The particular gyrotron under test generates a right-handed TE22.6 circular waveguide mode, and is designed to produce megawatt power levels over pulse durations on the order of 5 s. This high power level provides

  2. Memantine reduces hematoma expansion in experimental intracerebral hemorrhage, resulting in functional improvement

    Microsoft Academic Search

    Soon-Tae Lee; Kon Chu; Keun-Hwa Jung; Juhyun Kim; Eun-Hee Kim; Se-Jeong Kim; Dong-In Sinn; Song-Yi Ko; Manho Kim; Jae-Kyu Roh; J-K Roh

    2006-01-01

    Glutamate is accumulated in abundance during the early period of experimental hematoma, and the activation of N-methyl-D-aspartate (NMDA) receptors by glutamate can result in an influx of calcium and neuronal death in cases of intracerebral hemorrhage (ICH). Memantine, which is known to be a moderate-affinity, uncompetitive, NMDA receptor antagonist, was investigated with regard to its ability to block the glutamate

  3. 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.

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

    Microsoft Academic Search

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

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

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

    E-print Network

    Franchek, Nancy Marie

    1992-01-01

    configurations are experimentally tested for their static and dynamic characteristics, including flowrate, load ca- pacity, direct stiffness, and whirl frequency ratio. Comparisons of the results are made between bearings to determine which bearing has... 135 140 140 140 141 141 144 REFERENCES . VITA 145 148 vn LIST OF TABLES Page Onset Speed of Instability at the HS, HP, ZE Condition. . . 82 Static Parameter Uncertainties (Kurtin, et aL, 1991). . . . 86 Relative Sensitivities to Changes...

  6. The Simulation and Experimental Results of Dynamic Behaviour of Torque Motor Having Permanent Magnets

    NASA Astrophysics Data System (ADS)

    Despotovi?, Željko; Šinik, Vladimir

    2015-03-01

    The application, construction, and principle of operation of the torque motor having permanent magnets are presented first. Since dynamic behaviour of a servohydraulic system is, to a large extent, determined by dynamic behaviour of the applied torque motor, an analysis of motor's dynamic behaviour is carried out and its dynamic transfer characteristic is determined. Finally, the simulation and experimental results of dynamic behaviour of the torque motor are presented.

  7. Two Coupled Superconducting Cavities as a Gravitational Wave Detector: First Experimental Results

    E-print Network

    Ph. Bernard; G. Gemme; R. Parodi; E. Picasso

    1999-11-08

    First experimental results of a feasibility study of a gravitational wave detector based on two coupled superconducting cavities are presented. Basic physical principles underlying the detector behaviour and sensitivity limits are discussed. The detector layout is described in detail and its rf properties are showed. The limit sensitivity to small harmonic displacements at the detection frequency (around 1 MHz) is showed. The system performance as a potential g.w. detector is discussed and future developments are foreseen.

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

    PubMed Central

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

    2012-01-01

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

  9. SPES-2, experimental results from the S00908 blind test: Cold leg balance line DEG break

    SciTech Connect

    Medich, C.; Rigamonti, M.; Bacchiani, M. [SIET S.p.A., Piacenza (Italy); Conway, L. [Westinghouse Electric Co., Pittsburgh, PA (United States); Tarantini, M. [ENEA-ERG-FISS, Bologna (Italy)

    1996-07-01

    The SPES-2 is a full height, full pressure experimental test facility reproducing the Westinghouse AP600 reactor with a scaling factor of 1/395. The experimental plant, designed and operated by, SIET in Piacenza, consists of a full simulation of the AP600 primary core cooling system including all the passive safety and active non-safety systems. In 1992, Westinghouse, in cooperation with ENEL, ENEA, SIET and ANSALDO developed an experimental program to test the integrated behavior of the AP600 passive safety systems. The SPES-2 test matrix, concluded in November `94, has examined the AP600 passive safety system response for a range of small break LOCAs at different locations on the primary system and on the passive system lines; single steam generator tube ruptures with both passive and active nonsafety systems, and a main steam line break transient to demonstrate the capability of passive safety systems for rapid cooldown. Each of the tests has provided detailed experimental results for verification of the capability of the analysis methods to predict the integrated passive safety system behavior.

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

    NASA Astrophysics Data System (ADS)

    Sinitsyn, Oleksandr; Nusinovich, Gregory; Antonsen, Thomas

    2010-11-01

    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.

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

    SciTech Connect

    Munoz Camacho, Carlos [Institut de Physique Nucleaire, Orsay

    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.

  12. Energy efficient motors for HVAC applications: An experimental approach

    SciTech Connect

    Jowett, J.; Biesemeyer, W.D.

    1995-06-01

    The empirically derived data presented in this paper are the result of a program established by the State of Arizona to replace all the existing HVAC motors in the majority of State-owned buildings. All motors from 5 HP up were selected as candidates for retrofit. The largest motor was 125 HP. After obtaining questionable data from the initial existing motor field measurements, it was decided that some further study and testing was needed. By dynamometer testing aging motors from the field and new energy efficient motors, some startling conclusions were realized. One of the most common methods for determining motor loads in the field, the slip method, is highly inaccurate and cannot be used to reliably determine the load on the motor. Field measurements reconciled with dynamometer testing reveals that the slip method can be over 40% in error. Replacing an existing motor with an energy efficient motor may actually use more energy due to the effects of full load speed differences. Energy efficient motors generally run faster than standard motors because of the inherent lower internal losses. However, because the power required by a centrifugal load induction motor varies as the cube of the speed, the savings due to the higher efficiency may be completely offset by the increased power requirement due to the faster speed. Some of the conventional practices for protecting and determining energy savings from HVAC system energy efficient motor retrofits are misleading. Using the slip method for calculating motor load and not accounting for the speed difference between the existing motor and new motor are two examples presented here.

  13. Experimental Verification of the Thermodynamics of Critical Aspects of the Carbothermic Reduction of Alumina. Part 1: Experimental Result of Reacting Al2O3-C Mixtures

    NASA Astrophysics Data System (ADS)

    Walker, Matthew S.; Fruehan, Richard J.

    2013-08-01

    The thermodynamics of several aspects of the carbothermic reduction of the alumina process were experimentally verified. The current thermodynamics are based on solution models for the Al2O3-Al4C3 system and the free energies of formation of a number of phases. In Part I of this paper, the results of reacting carbon and alumina mixtures at high temperatures 2173 K to 2323 K (1900 °C to 2050 °C) are presented. The amount of CO evolved was measured and slag samples analyzed. The initial slag or carbide formation at alumina saturation was measured to be 2220 K (1947 °C) and 1.76 pct C. The slag-making temperature and composition in the liquid region were determined and at carbide saturation were measured to be 2273 K (2000 °C) and 6.29 pct C, respectively. Considering the experimental challenges at the high temperature, with the exception of the initial slag composition, the agreement with the predicted thermodynamics is good.

  14. 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.

  15. 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.

  16. 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.

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

    SciTech Connect

    Dogan, M.; Ulu, M. [eCOL Laboratory, Department of Physics, Science and Arts Faculty, Afyon Kocatepe University, 03200 Afyonkarahisar (Turkey); Gennarakis, G. G.; Zouros, T. J. M. [Atomic Collisions and Electron Spectroscopy Laboratory, Department of Physics, University of Crete, P.O. Box 2208, 71003 Heraklion, Crete (Greece)

    2013-04-15

    A specially designed hemispherical deflector analyzer (HDA) with 5-element input lens having a movable entry position R{sub 0} suitable for electron energy analysis in atomic collisions was constructed and tested. The energy resolution of the HDA was experimentally determined for three different entry positions R{sub 0}= 84, 100, 112 mm as a function of the nominal entry potential V(R{sub 0}) under pre-retardation conditions. The resolution for the (conventional) entry at the mean radius R{sub 0}= 100 mm was found to be a factor of 1.6-2 times worse than the resolution for the two (paracentric) positions R{sub 0}= 84 and 112 mm at particular values of V(R{sub 0}). These results provide the first experimental verification and a proof of principle of the utility of such a paracentric HDA, while demonstrating its advantages over the conventional HDA: greater dispersion with reduced angular aberrations resulting in better energy resolution without the use of any additional fringing field correction electrodes. Supporting simulations of the entire lens plus HDA spectrometer are also provided and mostly found to be within 20%-30% of experimental values. The paracentric HDA is expected to provide a lower cost and/or more compact alternative to the conventional HDA particularly useful in modern applications utilizing a position sensitive detector.

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

    PubMed

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

    2013-04-01

    A specially designed hemispherical deflector analyzer (HDA) with 5-element input lens having a movable entry position R0 suitable for electron energy analysis in atomic collisions was constructed and tested. The energy resolution of the HDA was experimentally determined for three different entry positions R0 = 84, 100, 112 mm as a function of the nominal entry potential V(R0) under pre-retardation conditions. The resolution for the (conventional) entry at the mean radius R0 = 100 mm was found to be a factor of 1.6-2 times worse than the resolution for the two (paracentric) positions R0 = 84 and 112 mm at particular values of V(R0). These results provide the first experimental verification and a proof of principle of the utility of such a paracentric HDA, while demonstrating its advantages over the conventional HDA: greater dispersion with reduced angular aberrations resulting in better energy resolution without the use of any additional fringing field correction electrodes. Supporting simulations of the entire lens plus HDA spectrometer are also provided and mostly found to be within 20%-30% of experimental values. The paracentric HDA is expected to provide a lower cost and?or more compact alternative to the conventional HDA particularly useful in modern applications utilizing a position sensitive detector. PMID:23635179

  19. 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.

  20. Use of dynamic theory to describe experimental results from volume holography

    NASA Technical Reports Server (NTRS)

    Magnusson, R.; Gaylord, T. K.

    1976-01-01

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

  1. Research in experimental and theoretical high energy physics

    NASA Astrophysics Data System (ADS)

    Bodek, A.; Ferbel, T.; Melissinos, A. C.; Olsen, S.; Slattery, P.; Das, A.; Hagen, C. R.; Mathur, V.; Okubo, S.; Rajeev, S. G.

    1989-06-01

    The Experimental High Energy Physics Program is directed toward the execution of experiments at both national and international accelerator facilities. During the next fiscal year, we will be primarily concentrating on the following projects: Fermilab direct photon experiment E706; Tevatron proton-antiproton collider experiment D-Zero; Analysis of Fermilab neutrino experiments and hadron experiment; Analysis of SLAC experiment E140 and all previous SLAC data; Running of the SLAC E140 extension (approved to run in 89/90); SLAC experiment NE11 (ran in 1989); Brookhaven galactic axion experiment; Coherent production of axions and Dellbruck scattering at BNL; The AMY experiment at TRISTAN; and Laser Switched LINAC at the Rochester Laser Laboratory. Projects which are in the completion stages: Search for new states of matter using the Rochester Tandem and SLAC experiment E141 Axion search. Projects in study and planning stages: Nonlinear Compton Scattering at LEP; Production of hybrid mesons in the nuclear coulomb field; Neutrino experiment for the Tevatron upgrade and the SSC; and Involvement in the CDF upgrade and the SSC.

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

    NASA Astrophysics Data System (ADS)

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

    2014-04-01

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

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

    SciTech Connect

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

    1997-11-01

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

  4. Oscillatory enhancement of the squeezing flow of yield stress fluids: a novel experimental result

    NASA Astrophysics Data System (ADS)

    Zwick, K. J.; Ayyaswamy, P. S.; Cohen, I. M.

    1997-05-01

    The extrusion of a yield stress fluid from the space between two parallel plates is investigated experimentally. Oscillating the magnitude of the squeezing force about a mean value (F=f[1+[alpha]cos([omega]t)]) was observed to significantly enhance the flow rate of yield stress fluids, while having no effect on the flow rate of Newtonian fluids. This is a novel result. The enhancement depends on the magnitude of the force, the oscillatory frequency and amplitude, the fluid being squeezed, and the thickness of the fluid layer. Non-dimensional results for the various flow quantities have been presented by using the flow predicted for the constant-force squeezing of a Herschel Bulkley yield stress fluid as the reference. In the limit of constant-force squeezing, the present experimental results compare very well with those of our earlier theoretical model for this situation (Zwick, Ayyaswamy & Cohen 1996). The results presented in this paper have significance, among many applications, for injection moulding, in the adhesive bonding of microelectronic chips, and in surgical procedures employed in health care.

  5. Experimental Demonstration of Energy-Chirp Compensation by a Tunable Dielectric-Based Structure

    NASA Astrophysics Data System (ADS)

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

    2014-03-01

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

  6. 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.

  7. LNG fires: a review of experimental results, models and hazard prediction challenges.

    PubMed

    Raj, Phani K

    2007-02-20

    A number of experimental investigations of LNG fires (of sizes 35 m diameter and smaller) were undertaken, world wide, during the 1970s and 1980s to study their physical and radiative characteristics. This paper reviews the published data from several of these tests including from the largest test to date, the 35 m, Montoir tests. Also reviewed in this paper is the state of the art in modeling LNG pool and vapor fires, including thermal radiation hazard modeling. The review is limited to considering the integral and semi-empirical models (solid flame and point source); CFD models are not reviewed. Several aspects of modeling LNG fires are reviewed including, the physical characteristics, such as the (visible) fire size and shape, tilt and drag in windy conditions, smoke production, radiant thermal output, etc., and the consideration of experimental data in the models. Comparisons of model results with experimental data are indicated and current deficiencies in modeling are discussed. The requirements in the US and European regulations related to LNG fire hazard assessment are reviewed, in brief, in the light of model inaccuracies, criteria for hazards to people and structures, and the effects of mitigating circumstances. The paper identifies: (i) critical parameters for which there exist no data, (ii) uncertainties and unknowns in modeling and (iii) deficiencies and gaps in current regulatory recipes for predicting hazards. PMID:17156916

  8. 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.

  9. 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

  10. 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.

  11. 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.

  12. Mechanisms for subcritical penetration into a sandy bottom: experimental and modeling results

    PubMed

    Maguer; Fox; Schmidt; Pouliquen; Bovio

    2000-03-01

    This paper presents preliminary results of a recent study whose overall objectives are to determine the mechanisms contributing significantly to subcritical acoustic penetration into ocean sediments, and to quantify the results for use in sonar performance prediction for the detection of buried objects. In situ acoustic measurements were performed on a sandy bottom whose geoacoustical and geomorphological properties were also measured. A parametric array mounted on a tower moving on a rail was used to insonify hydrophones located above and below the sediment interface. Data covering grazing angles both above and below the nominal critical angle and in the frequency range 2-15 kHz were acquired and processed. The results are compared to two models that account for scattering of sound at the rough water-sediment interface into the sediment. Although all possible mechanisms for subcritical penetration are not modeled, the levels predicted by both models are consistent with the levels observed in the experimental data. For the specific seafloor and experimental conditions examined, the analysis suggests that for frequencies below 5-7 kHz sound penetration into the sediment at subcritical insonification is dominated by the evanescent field, while scattering due to surface roughness is the dominant mechanism at higher frequencies. PMID:10738778

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

    E-print Network

    California at Davis, University of

    exacerbated in CA due to extreme off-shore water depths. #12;California Renewable Energy Center Future. Project analysis tool adapted to in-conduit small hydro #12;California Renewable Energy Center 335 GeneralRESEARCH RESULTS FORUM FOR RENEWABLE ENERGY TECHNOLOGY AND RESOURCE ASSESSMENTS Public Workshop

  14. 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.

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

    NASA Astrophysics Data System (ADS)

    Mattei, Giorgio; Fornari, Bruno; Pagannone, Mario

    1980-10-01

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

  16. Experimental and computational flow-field results for an all-body hypersonic aircraft

    NASA Technical Reports Server (NTRS)

    Cleary, Joseph W.

    1989-01-01

    A comprehensive test program is defined which is being implemented in the NASA/Ames 3.5 foot Hypersonic Wind Tunnel for obtaining data on a generic all-body hypersonic vehicle for computational fluid dynamics (CFD) code validation. Computational methods (approximate inviscid methods and an upwind parabolized Navier-Stokes code) currently being applied to the all-body model are outlined. Experimental and computational results on surface pressure distributions and Pitot-pressure surveys for the basic sharp-nose model (without control surfaces) at a free-stream Mach number of 7 are presented.

  17. Nucleate pool boiling in subcooled liquid under microgravity: Results of TEXUS experimental investigations

    NASA Astrophysics Data System (ADS)

    Zell, M.; Straub, J.; Weinzierl, A.

    1984-12-01

    Experiments on subcooled nucleate pool boiling in microgravity were carried out to separate gravity driven effects on heat transfer within the boiling process. A ballistic trajectory by sounding rocket flight (TEXUS 5 and 10) achieved a gravity level of a/g = 0.0001 for 360 sec. For determination of geometrical effects on heat transport two different experimental configurations (platinum wire and flat plate) were employed. Boiling curves and bubble dynamics recorded by cinematography lead to gravity independent modelling of the boiling phenomena. The results ensure the applicability and high efficiency of nucleate pool boiling for heat exchangers in space laboratories.

  18. 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.

  19. 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.

  20. Experimental study of targeted energy transfer from an acoustic system to a nonlinear membrane absorber

    NASA Astrophysics Data System (ADS)

    Bellet, R.; Cochelin, B.; Herzog, P.; Mattei, P.-O.

    2010-07-01

    This paper deals with the application of the concept of targeted energy transfer to the field of acoustics, providing a new approach to passive sound control in the low frequency domain, where no efficient dissipative mechanism exists. The targeted energy transfer, also called energy pumping, is a phenomenon that we observe by combining a pure nonlinear oscillator with a linear primary system. It corresponds to an almost irreversible transfer of vibration energy from the linear system to the auxiliary nonlinear one, where the energy is finally dissipated. In this study, an experimental set-up has been developed using the air inside a tube as the acoustic linear system, a thin circular visco-elastic membrane as an essentially cubic oscillator and the air inside a box as a weak coupling between those two elements. In this paper, which mainly deals with experimental results, it is shown that several regimes exist under sinusoidal forcing, corresponding to the different nonlinear normal modes of the system. One of these regimes is the quasi-periodic energy pumping regime. The targeted energy transfer phenomenon is also visible on the free oscillations of the system. Indeed, above an initial excitation threshold, the sound extinction in the tube follows a quasi-linear decrease that is much faster than the usual exponential one. During this linear decrease, the energy of the acoustic medium is irreversibly transferred to the membrane and then damped into this element called nonlinear energy sink. We present also the frequency responses of the system which shows a clipping of the original resonance peak of the acoustic medium and we finally demonstrate the ability of the nonlinear absorber to operate in a large frequency band, tuning itself to any linear system.

  1. 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.

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

    NASA Astrophysics Data System (ADS)

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

    1984-09-01

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

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

    SciTech Connect

    Zhang, Jinsuo [Los Alamos National Laboratory

    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.

  4. 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.

  5. Vibration of bimodular sandwich beams with thick facings: A new theory and experimental results

    NASA Astrophysics Data System (ADS)

    Rebello, C. A.; Bert, C. W.; Gordaninejad, F.

    1983-10-01

    This study deals with both analytical and experimental investigations of three-layer beams with cores of polyurethane foam and facings of unidirectional cord-rubber. Both of these materials are bimodular (i.e., having different behavior in compression as compared to tension). The new theory presented is a shear-flexible laminate version of the well-known Timoshenko beam theory, which, due to the bending-stretching coupling present in the bimodular case, results in a coupled sixth-order system of differential equations. In this theory, a separate derivation is presented for the shear correction factor. Due to the discontinuities in the normal stress distribution and the bimodularity, the shear correction factor is much different than the classical homogeneous material value of {5}/{6}. Theoretical and experimental results are presented for the frequencies of the first three modes of vibration for a pin-ended beam without axial restraint. This work is believed to be the first devoted to vibration of bimodular materials in a sandwich configuration.

  6. Assessment of in-furnace dry sorbent injection experimental results burning low sulphur content coals

    SciTech Connect

    Collado, F.J. [Univ. de Zaragoza (Spain)

    1995-12-31

    In an effort to adjust the SO{sub 2} emissions of coal power stations to the current air pollutant standards, established by the EC, flue gas desulfurization tests with in-furnace dry sorbent injection technology in the Spanish coal power station ``Litoral`` (tangentially-fired) were performed. The measured retentions were lower than predicted through a one-dimensional model. Then, it was thought that a CFD 3D simulation of the injection would help to understand the complex relationships of the process. The simulation was divided in two stages: in the first one, the turbulent velocity and the temperature field were solved. In the second one, representative sorbent particles were injected in the turbulent field previously solved, the focus of this work being the global sulphur capture modeling and its validation through the experimental measurements obtained. After a revision of the models proposed in the specialized literature, a global sulfation model is chosen, being compared with the experimental data obtained in the power station. Because of the main results of this work, the authors can highlight the testing of the laboratory-scale correlations against full-scale results, and can mitigate the difficulty of estimating the actual temperature profile by experimenting with the particle and its residence time without the aid of a CFD code.

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

    SciTech Connect

    Lappin, A. R.

    1980-07-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2014-09-01

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

  9. 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.

  10. 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.

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

    SciTech Connect

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

    1996-04-15

    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.

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

    NASA Technical Reports Server (NTRS)

    Rollbuhler, Jim

    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.

  13. 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.

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

    SciTech Connect

    Martin, J.A. [Lockheed Martin Corp., Schenectady, NY (United States)

    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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. Active Piezoelectric Energy Harvesting: General Principle and Experimental Demonstration

    Microsoft Academic Search

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

    2009-01-01

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

  20. 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.

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

    E-print Network

    Chen, Sheng

    Motivations PSO Aided OFR Based RBF Classifier Experimental Results Conclusions Radial Basis on Neural Networks 2010 #12;Motivations PSO Aided OFR Based RBF Classifier Experimental Results Conclusions Outline 1 Motivations Existing Approaches Our Novelty 2 PSO Aided OFR Based RBF Classifier Tunable RBF

  2. The influence of taxes and subsidies on energy purchased in an experimental purchasing study.

    PubMed

    Epstein, Leonard H; Dearing, Kelly K; Roba, Lora G; Finkelstein, Eric

    2010-03-01

    There is limited research on how taxes and subsidies would influence the energy and nutritional quality of food purchases. Using an experimental analogue purchasing task, we examined the effects of increasing the price of high-calorie-for-nutrient foods or reducing the price of low-calorie-for-nutrient foods by 12.5% and 25% on mothers' purchases of 68 common foods and drinks. Taxing less healthy foods with low nutrient density reduced energy (caloric) intake, while reducing the proportion of fat and increasing the proportion of protein purchased. Subsidizing more healthful foods with high nutrient density increased energy intake, without changing the macronutrient profile of foods purchased. These results favor taxes as a way to reduce caloric intake. PMID:20424078

  3. Simulated and experimental studies on identification of impact load with the transient statistical energy analysis method

    NASA Astrophysics Data System (ADS)

    Mao, B. Y.; Xie, S. L.; Xu, M. L.; Zhang, X. N.; Zhang, G. H.

    2014-06-01

    A new identification method of impact load is proposed based on the transient statistical energy analysis theory in the paper. Firstly, the location and input energy of impact load are identified according to the energy balance equation with a two-stage identification scheme from the averaged kinetic energy responses of subsystems. Secondly, the impact load amplitude spectrum is derived from the identified impact load input energy based on the Parseval theorem under the constant value assumption within each analysis frequency band. Lastly, a parametric fitting approach is developed to reconstruct further the time history of impact load for the given time domain waveform from the identified impact load amplitude spectrum. The impact load identification approach is qualified through the simulated and experimental studies for a two-plate coupling structural system and the simulated study for a three-plate coupling structure system. The results show that the location and input energy of impact load can be identified accurately using the presented method. The derived impact load amplitude spectrums have reasonable agreements with the real ones. As a result, the reconstructed impact load time histories by the fitting method agree well with the real impact load time histories. The present approach provides an effective and feasible way for impact load identification of engineering structures.

  4. Drying in porous media with gravity-stabilized fronts: experimental results.

    PubMed

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

    2012-08-01

    In a recent paper [Yiotis et al., Phys. Rev. E 85, 046308 (2012)] we developed a model for the drying of porous media in the presence of gravity. It incorporated effects of corner film flow, internal and external mass transfer, and the effect of gravity. Analytical results were derived when gravity opposes drying and hence leads to a stable percolation drying front. In this paper, we test the theory using laboratory experiments. A series of isothermal drying experiments in glass bead packings saturated with volatile hydrocarbons is conducted. The transparent glass cells containing the packing allow for the visual monitoring of the phase distribution patterns below the surface, including the formation of liquid films, as the gaseous phase invades the pore space, and for the control of the thickness of the diffusive mass boundary layer over the packing. The experimental results agree very well with theory, provided that the latter is generalized to account for the effects of corner roundness in the film region (which was neglected in the theoretical part). We demonstrate the existence of an early constant rate period (CRP), which lasts as long as the films saturate the surface of the packing, and of a subsequent falling rate period (FRP), which begins practically after the detachment of the film tips from the external surface. During the CRP, the process is controlled by diffusion within the stagnant gaseous phase in the upper part of the cells, yielding a Stefan tube problem solution. During the FRP, the process is controlled by diffusion within the packing, with a drying rate inversely proportional to the observed position of the film tips in the cell. Theoretical and experimental results compare favorably for a specific value of the roundness of the films, which is found to be constant and equal to 0.2 for various conditions, and verify the theoretical dependence on the capillary Ca(f), Bond Bo, and Sherwood Sh numbers. PMID:23005857

  5. Theory, simulation and experimental results of the acoustic detection of magnetization changes in superparamagnetic iron oxide

    PubMed Central

    2011-01-01

    Background Magnetic Particle Imaging is a novel method for medical imaging. It can be used to measure the local concentration of a tracer material based on iron oxide nanoparticles. While the resulting images show the distribution of the tracer material in phantoms or anatomic structures of subjects under examination, no information about the tissue is being acquired. To expand Magnetic Particle Imaging into the detection of soft tissue properties, a new method is proposed, which detects acoustic emissions caused by magnetization changes in superparamagnetic iron oxide. Methods Starting from an introduction to the theory of acoustically detected Magnetic Particle Imaging, a comparison to magnetically detected Magnetic Particle Imaging is presented. Furthermore, an experimental setup for the detection of acoustic emissions is described, which consists of the necessary field generating components, i.e. coils and permanent magnets, as well as a calibrated microphone to perform the detection. Results The estimated detection limit of acoustic Magnetic Particle Imaging is comparable to the detection limit of magnetic resonance imaging for iron oxide nanoparticles, whereas both are inferior to the theoretical detection limit for magnetically detected Magnetic Particle Imaging. Sufficient data was acquired to perform a comparison to the simulated data. The experimental results are in agreement with the simulations. The remaining differences can be well explained. Conclusions It was possible to demonstrate the detection of acoustic emissions of magnetic tracer materials in Magnetic Particle Imaging. The processing of acoustic emission in addition to the tracer distribution acquired by magnetic detection might allow for the extraction of mechanical tissue parameters. Such parameters, like for example the velocity of sound and the attenuation caused by the tissue, might also be used to support and improve ultrasound imaging. However, the method can also be used to perform imaging on its own. PMID:21711569

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

    NASA Astrophysics Data System (ADS)

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

    2011-11-01

    Recent computational and experimental advances at the St. Anthony Falls Laboratory (SAFL) aimed at understanding the structure of turbulence past wind and hydrokinetic turbines and farms will be presented. A powerful computational framework has been developed for carrying out LES of turbulent flow past complete turbine configurations as well as large-scale wind farms. For the former, the geometrical details of the turbine are resolved on fine computational grids using the CURVIB method with a wall model (Kang et al., Adv. in Water Resources, 34(1), 98-113, 2011) while for the latter the turbines are parametrized as actuator disks. Laboratory experiments in the SAFL atmospheric boundary layer wind tunnel and a large water flume have provided data sets for model validation. The computed and experimental results yield novel insights into the structure of turbulence in turbine wakes and suggest strategies for optimizing layouts of multi-turbine arrays for maximizing energy capture. This work was supported by Department of Energy DOE (DE-EE0002980), Xcel Energy through the Renewable Development Fund (grant RD3-42), Verdant Power Inc., and the University of Minnesota Initiative for Renewable Energy and the Environment.

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

    PubMed

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

    1989-01-01

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

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

    PubMed

    McKown, R D; Ridley, R K

    1995-02-01

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

  9. 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.

  10. Photoinduced random molecular reorientation by nonradiative energy relaxation: An experimental test

    SciTech Connect

    Manzo, C.; Paparo, D.; Marrucci, L. [INFM-Coherentia and Universita 'Federico II', Dipartimento di Scienze Fisiche, Complesso di Monte S. Angelo, via Cintia, 80126 Naples (Italy)

    2004-11-01

    By measuring the time-resolved fluorescence depolarization as a function of light excitation wavelength we address the question of a possible photoinduced orientational randomization of amino-anthraquinone dyes in liquid solutions. We find no significant dependence within the experimental uncertainties of both the initial molecule anisotropy and of the subsequent rotational diffusion dynamics on the photon energy. This indicates that this effect, if present, must be very small. A simple model of photoinduced local heating and corresponding enhanced rotational diffusion is in accordance with this result. This null result rules out some recent proposals that photoinduced local heating may contribute significantly to molecular reorientation effects in different materials. A small but statistically significant effect of photon energy is instead found in the excited-state lifetime of the dye.

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

    SciTech Connect

    Buzurovic, I.; Yu, Y.; Werner-Wasik, M.; Biswas, T.; Anne, P. R.; Dicker, A. P.; Podder, T. K. [Department of Radiation Oncology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107 (United States); Department of Radiation Oncology, University Hospitals Case Medical Center, Cleveland, Ohio 44106 (United States); Department of Radiation Oncology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107 (United States); Department of Radiation Oncology, University Hospitals Case Medical Center, Cleveland, Ohio 44106 (United States)

    2012-11-15

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

  12. 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.

  13. Experimental and numerical results of the influence of dynamic Poisson effect on transient pipe flow parameters

    NASA Astrophysics Data System (ADS)

    Adamkowski, A.; Henclik, S.; Lewandowski, M.

    2010-08-01

    The dynamic fluid-structure interaction (FSI) during hydraulic transient is known to be of special importance for flexible or movable pipeline system. Some kinds of FSI effects can be observed however even for relatively rigidly supported pipeline. Such effects, not anticipated by the classic waterhammer theory, were identified during experiments on waterhammer phenomenon conducted at a laboratory rig in the Szewalski Institute of Fluid-Flow Machinery of the Polish Academy of Sciences in Gdansk (IMP PAN). Additional pressure oscillations of higher frequencies observed during experiments were supposed to be the result of dynamic fluid-structure interaction. The problem of hydraulic transient with FSI effect taken into account has been of IMP PAN interest for some time and the four equation model of the phenomenon was applied and implemented at a computer program. A method of characteristics with time marching procedure and a "wave method" for solving the resulted finite difference equations were used at the algorithm. Selected measured and computed pressure records during the transient are presented in the paper. The analyses of the results allows to conclude that the additional effects observed at experiments were really produced by FSI effect (Poisson coupling). Some discrepancies between experimental and numerical results exist however and the analysis and attempt to explain the causes of them are proposed as well.

  14. 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.

  15. Experimental demonstration of high two-photon time-energy entanglement

    SciTech Connect

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

    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.

  16. Infrared, Raman and VCD spectra of ( S)-(+)-Carvone-comparison of experimental and ab initio theoretical results

    Microsoft Academic Search

    Günter Georg Hoffmann

    2003-01-01

    The infrared, Raman and vibrational circular dichroism spectra of the rotational isomers of (S)-(+)-carvone have been calculated and compared to the experimental spectra. From the comparison, the conformeric composition of carvone could be deduced. It corresponded to the composition calculated from the energy differences of the two conformers with lowest energy for room temperature. A complete assignment of the vibrational

  17. Experimental validation of energy harvesting performance for pressure-loaded piezoelectric circular diaphragms

    Microsoft Academic Search

    Changki Mo; Leon J. Radziemski; William W. Clark

    2010-01-01

    Energy harvesting is a research area that has seen greatly increased interest in recent years. This paper presents experimental efforts to validate analytically predicted energy generating performance of piezoelectric harvesters for use in a pressure-loaded system. The energy harvesters adopted in this article are simply supported, partially covered piezoelectric unimorph circular diaphragms designed to capture energy from fluctuating pressure and

  18. Annual cycle energy system experimental performance and national applicability

    SciTech Connect

    Baxter, V.D.

    1981-01-01

    A single-family residence in Knoxville, Tennessee has been used to demonstrate the energy conserving potential of the Annual Cycle Energy System (ACES). For the past two years the performance of the ACES has been compared with that of two different air-to-air heat pumps in an identical house, the control house. The two heat pumps had ARI-rated COPs of 2.46 and 3.11 at 8.3/sup 0/C, representing both standard and best available heat pumps now on the market. Hot water for the control house was supplied by an electric resistance heater each year, while hot water for the ACES house was supplied by the ACES mechanical package. Performance results for the period December 1978 through September 1979 show that the ACES consumed 6719 kWh of electricity for an annual coefficient of performance (ACOP) of 2.80. The control house (with the ARI-2.46 heat pump) consumed 12,853 kWh of electricity, yielding an ACOP of 1.42. For December 1979 through September 15, 1980, the ACES consumed 6447 kWh of electricity for an ACOP of 3.08 while the control house, using the ARI-3.11 heat pump, consumed 11,358 kWh for an ACOP of 1.73. The ACES has achieved nearly all of its theoretical performance predictions and has verified its design criteria. This system has delivered residential heating and cooling services while consuming only 57% as much electricity as the best conventional alternative tested. Computer studies have shown the ACES to be applicable to all US climatic zones except those with very low heating needs.

  19. Comparison of simulation and experimental results for a gas puff nozzle on Ambiorix

    SciTech Connect

    Barnier, J-N.; Chevalier, J-M.; Dubroca, B. [CEA/CESTA, BP 2, 33114 Le Borp (France)

    1997-05-05

    One of source term of Z-Pinch experiments is the gas puff density profile. In order to characterize the gas jet, an experiment based on interferometry has been performed. The first study was a point measurement (a section density profile) which led us to develop a global and instantaneous interferometry imaging method. In order to optimise the nozzle, we simulated the experiment with a flow calculation code (ARES). In this paper, the experimental results are compared with simulations. The different gas properties (He, Ne, Ar) and the flow duration lead us to take care, on the one hand, of the gas viscosity, and on the other, of modifying the code for an instationary flow.

  20. 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.

  1. Comparison of experimental results in the domestic tests of the Japanese and Euratom-LCT-coils

    SciTech Connect

    Tsuji, H.; Komarek, P.; Shimamoto, S.; Ulbricht, A.; Wuchner, F.

    1985-07-01

    The Large Coil Task, an international technology program under the auspices of the IEA, has been conducted to develop large superconducting toroidal coils for tokamaks by the participation of the U.S., Switzerland, Euratom, and Japan. Among the six coils being developed under this program, domestic tests of the pool-cooled Japanese coil in June 1982 and of the forced-cooled Euratom coil in April 1984 were successfully carried out prior to shipment and installation at the LCTF in ORNL. These two LCT coils are the first ones which show experimentally the characteristics of pool-cooled and forced-cooled large coils for TOKAMAK machines. Major results obtained by the two domestic tests are described from the view of comparison of both cooling systems.

  2. 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.

  3. Photopumping and fluorescence in a laser-produced plasma. I. Experimental results

    NASA Astrophysics Data System (ADS)

    Back, C. A.; Chenais-Popovics, C.; Lee, R. W.

    1991-11-01

    A complete series of three experiments dedicated to the study of a photopumping and resonance fluorescence scheme is presented. An aluminum plasma is preformed in the heliumlike ground state by a 2-J 1.06-?m laser beam, then this plasma is photopumped by an x-ray source ~1 ns later. The pump is a spatially distinct laser-produced plasma that emits intense emission of the heliumlike resonance lines in the 4-8-Å region. The pump is line coincident with the transitions to be photopumped. The resulting perturbation is studied by the fluorescence, which is directly observed and absolutely quantified. The separate characterization of each component of this system is discussed in detail, with an emphasis on the experimental quantities that will be compared with numerical calculations.

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

    PubMed Central

    Casciano, Rebecca; Massey, Douglas S.

    2013-01-01

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

  5. Thermally and mechanically activated dislocation glide: Experimental results and theoretical analysis

    SciTech Connect

    Dunham, D.P.; Gibeling, J.C. (Univ. of California, Davis, CA (United States). Div. of Materials Science and Engineering)

    1993-04-01

    The results of room temperature stress rate change tests conducted on OFE copper are presented. The data exhibit apparent inelastic strain rate discontinuity at the point of stress rate change, indicating the presence of mechanical activation of dislocation glide. However, a new description of deformation that includes thermal and mechanical activation of glide is used to demonstrate that the current testing conditions could not have led to a measurable amount of mechanical activation. Further, a model of deformation that includes only thermal activation is shown to adequately describe the rapid strain rate decay observed in OFE copper following a stress rate decrease. This model indicates that the time resolution of 1 ms required to measure this decay is greater than the experimentally achieved time resolution of 28 ms. Together, these observations demonstrate that mechanical activation of dislocation glide was not detected in the present experiments. The analyses can also be used to predict the conditions under which mechanical activation may be observable.

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

    NASA Technical Reports Server (NTRS)

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

    1994-01-01

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

  7. The $^{22}$Ne($?$,n)$^{25}$Mg neutron source: latest experimental results and prospects

    E-print Network

    Claudio Ugalde

    2008-10-07

    The current status of the reaction rate of $^{22}$Ne($\\alpha$,n)$^{25}$Mg is summarized. Among the latest new results, probably the most relevant is the conclusion that the E$_x$=11.15 MeV state in $^{26}$Mg has a non-natural parity, so it does not contribute to the rates of the $\\alpha$ + $^{22}$Ne reactions. However, it may be possible that other neighboring states contribute to the neutron yield at stellar temperatures. Here we make an account of some of the experimental work in the literature that is relevant to this state. Indeed, it would have been possible to avoid the controversy regarding this state before it even started.

  8. Optical constants of Titan aerosols and their tholins analogs: Experimental results and modeling/observational data

    NASA Astrophysics Data System (ADS)

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

    2015-05-01

    Since Bishun Khare's pioneer works on Titan tholins, many studies have been performed to improve the experimental database of the optical constants of Titan tholins. The determination of the optical constants of Titan aerosols is indeed essential to quantify their capacity to absorb and scatter solar radiation, and thus to evaluate their role on Titan's radiative balance and climate. The study of the optical properties is also crucial to analyze and better interpret many of Titan's observational data, in particular those acquired during the Cassini-Huygens mission. This review paper critically summarizes these new results and presents constraints on Titan's aerosols optical constants. Finally, the information lacking in this field is highlighted as well as some possible investigations that could be carried out to fill these gaps.

  9. 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...

  10. Experimental energy barriers to anions transporting through nanofiltration membranes.

    PubMed

    Richards, Laura A; Richards, Bryce S; Corry, Ben; Schäfer, Andrea I

    2013-02-19

    Environmentally relevant contaminants fluoride, chloride, nitrate, and nitrite face Arrhenius energy barriers during transport through nanofiltration (NF) membranes. The energy barriers were quantified using crossflow filtration experiments and were in the range of 7-17 kcal·mol(-1), according to ion type and membrane type (Filmtec NF90 and NF270). Fluoride faced a comparatively high energy barrier for both membranes. This can be explained by the strong hydration energy of fluoride rather than other ion properties such as bare ion radius, fully hydrated radius, Stokes radius, diffusion coefficient, or ion charge. The energy barrier for fluoride decreased with pressure, indicating an impact of directional force on energy barriers. The influence of temperature-induced pore radius variability and viscosity on energy barriers was considered. The novel link between energy barriers and ion properties emphasizes the importance of ion hydration and/or partial dehydration mechanisms in determining transport in NF. PMID:23298263

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

    PubMed

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

    2014-10-01

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

  12. Systematic study to reduce the effects of cracks in multilayer insulation Part 2: experimental results

    NASA Astrophysics Data System (ADS)

    Shu, Q. S.; Fast, R. W.; Hart, H. L.

    A series of cracks with different widths and shapes was cut in a multilayer insulation (MLI) blanket. The measured data shows that the incremental heat load per unit slot area has a maximum of ? 135 W m -2. The heat load increment is essentially independent of the preparation of the cold surface under the crack, i.e. its emissivity, if the slot width is sufficiently small. The temperature distribution and the equivalent thermal conductivity near the cracks are quite different from that in a system without cracks. The dependence of the heat load and temperature distribution on the vacuum pressure was also observed. A systematic study of a crack-covering 'patch' method to reduce the heat load to a 77 K surface through cracks in a MLI blanket was conducted. The following patch materials were used to determine the optimum distribution of the patches in a 30 layer blanket: 300 Å ‡ single aluminized crinkled Mylar (NRC-2) and 1000 Å double aluminized flat Mylar. The experimental results indicated that the use of a patch every few layers is almost as effective as using a patch every layer. Placing the patches in the upper half of the blanket is much better than in the lower half and can reduce the heat load essentially to that without cracks. Putting the same number of patches on top of a crack is much less effective. The data suggest that 1000 Å material is preferable for patches. All of the experimental results are generally in agreement with the enhanced black cavity model.

  13. Reduction of FeO in smelting slags by solid carbon: Experimental results

    NASA Astrophysics Data System (ADS)

    Sarma, B.; Cramb, A. W.; Fruehan, R. J.

    1996-10-01

    The reduction of CaO-SiO2-Al2O3-FeO slags containing less than 10 wt pct FeO by solid carbonaceous materials such as graphite, coke, and coal char was investigated at reaction temperatures of 1400 °C to 1450 °C. The carbon monoxide evolution rate from the system was measured using stationary and rotating carbon rods, stationary horizontal carbon surfaces, and pinned stationary spheres as the reductants. The measured reaction rate ranged from 3.25 × 10-7 mol cm-2 s-1 at 2.1 pct FeO under static conditions to 3.6 × 10-6 mol cm-2 s-1 at 9.5 pct FeO for a rotating rod experiment. Visualization of the experiment using X-ray fluoroscopy showed that gas evolution from the reduction reaction caused the slag to foam during the experiment and that a gas film formed between the carbon surface and the slag at all times during experimentation. The reaction rate increased with increased slag FeO contents under all experimental conditions; however, this variation was not linear with FeO content. The reaction rate also increased with the rotation speed of the carbon rod at a given FeO content. A small increase in the reaction rate, at a given FeO content, was found when horizontal coke surfaces and coke spheres were used as the reductant as compared to graphite and coal char. The results of these experiments do not fit the traditional mass transfer correlations due to the evolution of gas during the experiment. The experimental results are consistent, however, with the hypothesis that liquid phase mass transfer of iron oxide is a major factor in the rate of reduction of iron oxide from slags by carbonaceous materials. In a second article, the individual rates of the possible limiting steps will be compared and a mixed control model will be used to explain the measured reaction rates.

  14. Pressurization test results: Bonneville Power Administration Energy Conservation Study

    Microsoft Academic Search

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

    1980-01-01

    Results are presented of air leakage measurements in 18 single-family detached houses at the Midway substation, Hanford, Washington, performed as part of the Bonneville Power Administration's Energy Conservation Study. The change in energy consumption following various retrofit strategies is compared. Air leakage was measured in each house with the fan pressurization technique, before and after the retrofits were installed. No

  15. Role of spherical particles on magnetic field recording in sediments: Experimental and numerical results

    NASA Astrophysics Data System (ADS)

    Bilardello, Dario; Jezek, Josef; Gilder, Stuart A.

    2013-01-01

    We report deposition experiments using spherical glass beads that possess remanent magnetizations stemming from iron impurities. 15 g of glass beads with a well-characterized size distribution were loaded in two different sets of tubes with diameters of 2.0 and 3.6 cm. Each tube contains identical column heights of de-ionized water, thereby allowing us to assess the effect of sediment concentration on the results (352 versus 90 kg/m3 [g/l], respectively). The tubes were placed in magnetic fields of variable inclination and intensity in a temperature-controlled environment. The full vector magnetization and sediment accumulation rates were measured upon deposition times ranging from 10 min to 10 days. Experiments were run in triplicate to evaluate data reproducibility. Together with the lack of magnetic interaction and the absence of clumping, the experiments elucidate an end-member scenario of how sediments acquire remanent magnetizations in the absence of flocculation. Our results show that inclination shallowing, in the range of 7-20° for field inclinations of 30° and 60°, is indeed possible with solely spherical particles. More importantly, we observe a field dependence on the inclination error. Field dependence on the moment acquisition and inclination error both exhibit non-linearity, which may complicate interpretations of relative paleointensity data in paleomagnetic records. A newly developed numerical model, whereby particle collision during settling combined with both rolling and slipping (translation) on the substrate, is consistent with the experimental results.

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

    NASA Astrophysics Data System (ADS)

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

    2012-04-01

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

  17. Plant Wide Energy Management and Reporting Systems Provide Sustainable Results

    E-print Network

    Robinson, J. E.

    2007-01-01

    Plant Wide Energy Management and Reporting Systems Provide Sustainable Results James E. Robinson, P.E., P.Eng. CEM, CEP Principal Project Engineer DES Canada, Corporation St. Albert, Alberta Canada ABSTRACT Powerhouse operators can...

  18. Energy Results of ISO 50001 Deployment by Program Administrators

    E-print Network

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

    2013-01-01

    Early Results of ISO 50001 Deployment by Utility Programs CHAD GILLESS PRACTICE LEAD, STRATEGIC ENERGY MANAGEMENT ENERNOC PORTLAND, OREGON KIM BROWN ASSOCIATE ENERNOC PORTLAND, OREGON DRESDEN SKEES- GREGORY SUSTAINABLE...

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

    NASA Astrophysics Data System (ADS)

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

    2014-07-01

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

  20. 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.

  1. 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.

  2. Ultra High Energy Cosmic Radiation: Experimental and Theoretical Status

    E-print Network

    Guenter Sigl

    2006-09-09

    We give a brief overview of the current experimental and theoretical status of cosmic rays above ~10**17 eV. We focus on the role of large scale magnetic fields and on multi-messenger aspects linking charged cosmic ray with secondary gamma-ray and neutrino fluxes.

  3. Proposal for New Experimental Tests of the Bose-Einstein Condensation Mechanism for Low Energy Nuclear Reaction and Transmutation Processes in Deuterium Loaded Micro and Nano Scale Cavities

    Microsoft Academic Search

    Yeong E. Kim; David S. Koltick; Ronald G. Reifenberger; Alexander L. Zubarev

    Most of experimental results of low energy nuclear reaction (LENR) reported so far cannot be reproduced on demand. There have been persistent experimental results indicating that the LENR and transmutation processes in condensed matters (LENRTPCM) are surface phenomena rather than bulk phenomena. Recently proposed Bose-Einstein condensation (BEC) mechanism may provide a suitable theoretical description of the surface phenomena. New experiments

  4. Second-order dynamic response of a large spar platform: Numerical predictions versus experimental results

    SciTech Connect

    Weggel, D.C.; Roesset, J.M. [Univ. of Texas, Austin, TX (United States). Offshore Technology Research Center

    1996-12-31

    The dynamic response of a large spar platform was investigated. A 1:55 scale model of the platform was tested at the wave basin of the Center at Texas A and M University. It was subjected to unidirectional monochromatic, bichromatic, and irregular waves in deep water. The prototype spar with a diameter of D = 40.5 m and a draft of h = 198.2 m would be moored to the sea floor in a water depth of 922 meters. Numerical predictions using second-order diffraction/radiation theory are compared in this paper to the experimental results to assess the degree of appropriateness provided by this theory alone. The first- and second-order diffraction forces and radiation coefficients were computed with WAMIT5.1s, a widely-used radiation/diffraction panel program for bodies of arbitrary geometry. The forces and radiation coefficients obtained for a truncated cylinder with the spar`s dimensions were then input into a program that calculates responses using the hydrodynamic equations of motion of a rigid body with three degrees of freedom. The response program interpolates between actual hydrodynamic force values computed by WAMIT so that high resolution spectral outputs can be obtained. Mooring lines were modeled by linear springs although their behavior was nonlinear for large displacements. The numerical and experimental responses for surge and pitch are compared in the form of time histories and spectral densities. The heave motion was not considered because it should be more strongly affected by viscous damping which was not included in the model.

  5. 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.

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

    PubMed Central

    Strupp, Christian

    2011-01-01

    The toxicity of soluble metal compounds is often different from that of the parent metal. Since no reliable data on acute toxicity, local effects, and mutagenicity of beryllium metal have ever been generated, beryllium metal powder was tested according to the respective Organisation for Economical Co-Operation and Development (OECD) guidelines. Acute oral toxicity of beryllium metal was investigated in rats and local effects on skin and eye in rabbits. Skin-sensitizing properties were investigated in guinea pigs (maximization method). Basic knowledge about systemic bioavailability is important for the design of genotoxicity tests on poorly soluble substances. Therefore, it was necessary to experimentally compare the capacities of beryllium chloride and beryllium metal to form ions under simulated human lung conditions. Solubility of beryllium metal in artificial lung fluid was low, while solubility in artificial lysosomal fluid was moderate. Beryllium chloride dissolution kinetics were largely different, and thus, metal extracts were used in the in vitro genotoxicity tests. Genotoxicity was investigated in vitro in a bacterial reverse mutagenicity assay, a mammalian cell gene mutation assay, a mammalian cell chromosome aberration assay, and an unscheduled DNA synthesis (UDS) assay. In addition, cell transformation was tested in a Syrian hamster embryo cell assay, and potential inhibition of DNA repair was tested by modification of the UDS assay. Beryllium metal was found not to be mutagenic or clastogenic based on the experimental in vitro results. Furthermore, treatment with beryllium metal extracts did not induce DNA repair synthesis, indicative of no DNA-damaging potential of beryllium metal. A cell-transforming potential and a tendency to inhibit DNA repair when the cell is severely damaged by an external stimulus were observed. Beryllium metal was also found not to be a skin or eye irritant, not to be a skin sensitizer, and not to have relevant acute oral toxic properties. PMID:21196457

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

    PubMed Central

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

    2009-01-01

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

  8. 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.

  9. Electron emission from surfaces resulting from low energy positron bombardment

    NASA Astrophysics Data System (ADS)

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

    2009-03-01

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

  10. Experimental results on the structure of hydronamic turbulence in accretion disks

    NASA Astrophysics Data System (ADS)

    Chertkov, Eli; Edlund, E. M.; Ji, H.

    2013-10-01

    The Princeton Hydrodynamic Turbulence Experiment (HTX) is a Taylor-Couette device with a variable speed rings at the axial boundaries and the ability to perturb quiescent flow regimes via a pump system. The experiment is designed to quantify purely hydrodynamic effects present in accretion disks, as well as study boundary effects, such as Ekman circulation and Stewartson layers, in Taylor-Couette systems. The results of this experiment supplement those of the Princeton MRI experiment, a Taylor-Couette device filled with a GaInSn fluid, which was designed to study the magnetorotational instability (MRI), the current explanation for observed accretion rates in accretion disks. The main diagnostic in HTX is a laser doppler velocimetry (LDV) system capable of correlating azimuthal and radial velocity measurements. We present recent experimental results on the lifetimes of turbulence forced by direct perturbations as a function of dimensionless rotational shear (q) as well as an autocorrelation analysis of the azimuthal velocity fluctuations in the quasi-Keplerian regime.

  11. Experimental result study and design enhancement of a magnetic pulse compression circuit by using the pspice simulation program

    Microsoft Academic Search

    M. Nehmadi; Y. Ifrah; I. Druckmann

    1990-01-01

    Magnetic pulse compression (MPC) is widely used to drive high-power pulsed lasers such as metal vapor, excimer, and chemical lasers. A simulation program has been successfully operated for the study and enhancement of experimental results. Starting from the experimental laser voltage and current wave forms, an equivalent time-varying impedance for the laser tube has been derived. This impedance is incorporated

  12. Angular distributions of photoelectrons from polarized ? atoms near threshold: experimental results and theoretical analysis

    Microsoft Academic Search

    S. Schohl; N. A. Cherepkov; I. D. Petrov; V. L. Sukhorukov; S. Baier; H. Hotop

    1998-01-01

    Following our recent mass spectrometric study of wavelength-dependent photoionization of laser-excited, polarized 0953-4075\\/31\\/15\\/010\\/img3 atoms near threshold (1997 30 609) we report electron angular distributions for photoionization of polarized 0953-4075\\/31\\/15\\/010\\/img3 atoms at four energies 0953-4075\\/31\\/15\\/010\\/img5 above the 0953-4075\\/31\\/15\\/010\\/img6 threshold. The measurements allow us to both check the atomic alignment produced in the optical pumping process and test in detail results of

  13. Spacecraft Power Beaming Using High-Energy Lasers, Experimental Validation

    Microsoft Academic Search

    Sherif Michael; Sherif

    2008-01-01

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

  14. Electron-energy spectra of H- doubly excited states resulting from collisions of H- with He

    NASA Astrophysics Data System (ADS)

    Kimura, M.; Sato, H.; Hino, K.; Matsuzawa, M.

    1994-09-01

    Electron-energy spectra for H- doubly excited states resulting from collisions of H- with He are rigorously calculated within a semiclassical molecular representation by including couplings between doubly excited states and continuum states and their interference with direct-detachment processes. An energy sampling procedure, based on the Gauss quadratures, is used to discretize continuum states. The present theoretical result clarifies mechanisms of excitation to doubly excited states, quantitatively reproduces the experimental spectra first observed by Risley and Geballe in 1974, separates the contributions from each of three doubly excited states, and identifies the cause of the interference between channels arising from double-electron excitation and direct detachment with simultaneous excitation.

  15. Electron emission from surfaces resulting from low energy positron bombardment

    NASA Astrophysics Data System (ADS)

    Mukherjee, Saurabh

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

  16. Negative refraction and energy funneling by hyperbolic materials: an experimental demonstration in acoustics.

    PubMed

    García-Chocano, Victor M; Christensen, Johan; Sánchez-Dehesa, José

    2014-04-11

    This Letter reports the design, fabrication, and experimental characterization of hyperbolic materials showing negative refraction and energy funneling of airborne sound. Negative refraction is demonstrated using a stack of five holey Plexiglas plates where their thicknesses, layer separation, hole diameters, and lattice periodicity have been determined to show hyperbolic dispersion around 40 kHz. The resulting hyperbolic material shows a flat band profile in the equifrequency contour allowing the gathering of acoustic energy in a broad range of incident angles and its funneling through the material. Our demonstrations foresee interesting developments based on both phenomena. Acoustic imaging with subwavelength resolution and spot-size converters that harvest and squeeze sound waves irradiating from many directions into a collimated beam are just two possible applications among many. PMID:24765970

  17. Experimental design to generate strong shear layers in a high-energy-density plasma

    NASA Astrophysics Data System (ADS)

    Harding, E. C.; Drake, R. P.; Aglitskiy, Y.; Gillespie, R. S.; Grosskopf, M. J.; Weaver, J. L.; Velikovich, A. L.; Visco, A.; Ditmar, J. R.

    2010-06-01

    The development of a new experimental system for generating a strong shear flow in a high-energy-density plasma is described in detail. The targets were designed with the goal of producing a diagnosable Kelvin-Helmholtz (KH) instability, which plays an important role in the transition turbulence but remains relatively unexplored in the high-energy-density regime. To generate the shear flow the Nike laser was used to drive a flow of Al plasma over a low-density foam surface with an initial perturbation. The interaction of the Al and foam was captured with a spherical crystal imager using 1.86 keV X-rays. The selection of the individual targets components is discussed and results are presented.

  18. Investigations in Experimental and Theoretical High Energy Physics

    SciTech Connect

    Krennrich, Frank [Iowa State University

    2013-07-29

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

  19. Review of Recent Results from the Rhic Beam Energy Scan

    NASA Astrophysics Data System (ADS)

    Kumar, Lokesh

    2013-10-01

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

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

    ERIC Educational Resources Information Center

    Precker, Jurgen W.

    2007-01-01

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

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

    SciTech Connect

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

    2004-05-12

    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.

  2. Experimental Optimization of Direct-Drive Implosions with Cross-Beam Energy Transfer

    NASA Astrophysics Data System (ADS)

    Froula, D. H.; Igumenshchev, I. V.; Seka, W.; Edgell, D. H.; Goncharov, V. N.

    2011-10-01

    Cross-beam energy transfer (CBET) in direct-drive implosions is measured to reduce the hydrodynamic efficiency of the laser drive. The outer rays of each beam interact through the ion-acoustic waves to extract energy from the central rays of each beam. This accounts for an ~10% loss of absorption, which results in an ~20% reduction in hydro-efficiency as measured by the scattered light and x-ray bang time. Experiments that reduce the laser energy in the outer rays by reducing the ratio of the laser spot size to target diameter by Rbeam/Rtarget = 60% are shown to eliminate CBET and significantly increase the hydrodynamic coupling; however, the reduction in laser spot size leads to irradiation nonuniformities. An optimum laser spot size is experimentally determined that maximizes neutron yield by balancing the reduced CBET with the illumination nonuniformities. This work was supported by the U.S. Department of Energy Office of Inertial Confinement Fusion under Cooperative Agreement No. DE-FC52-08NA28302. This work was supported by the U.S. Department of Energy Office of Inertial Confinement Fusion under Cooperative Agreement No. DE-FC52-08NA28302.

  3. An Analog Light Scattering Experiment of Hexagonal Icelike Particles. Part II: Experimental and Theoretical Results

    Microsoft Academic Search

    Brian Barkey; K. N. Liou; Yoshihide Takano; Werner Gellerman; Pierre Sokolsky

    1999-01-01

    The scattering properties of hexagonal icelike crystals as measured in the analog manner by the experimental apparatus described in Part I are presented. The crystals are made out of sodium fluoride (NaF), which has an index of refraction similar to that of water ice. The experimentally determined light intensities scattered from fixed and integrated random orientations of a NaF hexagonal

  4. Contribution from the experimental apparatus to the low energy background in Rutherford backscattering experiments

    Microsoft Academic Search

    L. Varga

    1986-01-01

    Low energy background was observed while bombarding a thin gold foil with protons. Measurements performed in different experimental arrangements and scattering calculations indicate that a large part of this background must arise from the pure energy definition of the bombarding beam. Particles of unknown origin and of lower energy than the nominal bombarding one were observed by which a separate

  5. Experimental study of low-energy muons in the stratosphere

    Microsoft Academic Search

    Iu. A. Aleksandrov; V. G. Afanas'ev; K. G. Afanas'ev; E. V. Gorchakov; V. A. Iozenas

    1990-01-01

    Instrumentation for recording 25 - 80 MeV muons is described, where an 8x8 sq cm cylindrical crystal is used as the detector. The geometric factor is calculated for various energy muons and for particles not stopped in the detector. The average geometric factor for muons with energies below 55 MeV is 0.025 sq m sr and vanishes for muons with

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

    PubMed

    Mershin, A; Kolomenski, A A; Schuessler, H A; Nanopoulos, D V

    2004-11-01

    We used computer simulation to calculate the electric dipole moments of the alpha- and beta-tubulin monomers and dimer and found those to be |p(alpha)| = 552D, |p(beta)| = 1193D and |p(alphabeta)| = 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 Deltan/Deltac approximately 1.800 x 10(-3)ml/mg. The refractive index of tubulin was measured to be n(tub) approximately 2.90 and the high-frequency tubulin dielectric constant k(tub) approximately 8.41, while the high-frequency polarizability was found to be alpha(tub) approximately 2.1 x 10(-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. PMID:15527947

  7. Experimental results of gain fluctuations and noise in microwave low-noise cryogenic amplifiers

    NASA Astrophysics Data System (ADS)

    Gallego, Juan D.; López-Fernández, Isaac; Diez, Carmen; Barcia, Alberto

    2004-05-01

    Applications like radio astronomy and space communications require ultimate sensitivity and make use of very particular receivers with state-of-the-art devices. Usually the receivers are cooled at cryogenic temperatures to reduce the noise even further. Noise temperatures of only a few times the quantum limit can be obtained in these conditions. During the past decade, Indium Phosphide HEMTs have demonstrated the best noise performance at cryogenic temperatures in the microwave frequency range of all active semiconductor devices, together with extremely low power consumption. For certain applications noise is not the only factor affecting the sensitivity. For example, gain fluctuations may play a dominant role in wide band radiometers. Unfortunately some of the factors that have contributed to improve the noise temperature have degraded the gain fluctuations. The operation at cryogenic temperatures also increases the fluctuations. This paper describes the experimental results obtained at the Centro Astronomico de Yebes (CAY) in the development of wide band cryogenic amplifiers. Special attention is paid to the influence of the bias point in noise and gain fluctuations. InP HEMTs from different foundries were tested. The amplifiers developed will be used in the Herschel ESA mission radiometers and the Atacama Large Millimeter Array (ALMA) receivers.

  8. Comparison between Simmons's Equations and Quantum Tunneling Experimental Results in A Thin Film

    NASA Astrophysics Data System (ADS)

    Ma, Lianxi

    2012-02-01

    The theoretical predictions of J.G. Simmons's equations are compared with quantum tunneling experimental results and a discrepancy is found at bias voltage Vb=U/e, where U is the barrier's potential height and e is the electron charge. Specifically, he divided the bias voltage into 2 regions: Vb < U/e and Vb > U/e, and the I -- V characteristics are different in these two regions. The derived equations show a kink on differential conductance dI/dV vs. Vb at Vb=U/e, because starts at this bias the thickness of the insulation film decreases with Vb in addition to the lowering of the barrier's average height. Therefore, the differential conductance decreases more rapidly in the region Vb > U/e than in the region Vb < U/e. However, in tunneling experiment in which Pt is used as conductor and solid neon as insulator, we have not observed such kink even the bias was increased to 4 volts. Our speculation is either 1) there should not be a kink on conductance at Vb=U/e so Simmons's equations need to be modified; 2) the kink should exist but bias voltage is not high enough to observe it in the experiments.

  9. A 2D optomechanical focused laser spot scanner: analysis and experimental results for microstereolithography

    NASA Astrophysics Data System (ADS)

    Gandhi, P. S.; Deshmukh, S.

    2010-01-01

    This paper proposes and analyzes a 2D optomechanical-focused laser spot scanning system (patent pending) which allows uniform intensity focused spot scanning with high speed and high resolution over a large range of scan. Such scanning is useful where variation of focused spot characteristics affects the performance of applications such as micro-/nano-stereolithography, laser micro-machining, scanning optical tweezers, optical scanning microscopy, and so on. Proposed scanning is achieved by using linear movement of mirrors and lens maintaining the alignment of motion and optical axis of laser. Higher speed and high resolution at the same time are achieved by use of two serial double parallelogram flexural mechanisms with mechatronics developed around them. Optical analysis is carried out to demonstrate effectiveness of the proposed system numerically and is further supported by the experimental results. Additional analysis is carried out to demonstrate robustness of the scanner in the case of small misalignment errors incurred in actual practice. Although the proposed scanner is useful in general in several applications mentioned above, discussion in this paper is focused on microstereolithography.

  10. Experimental results on a wall interference correction method with interface measurements

    NASA Technical Reports Server (NTRS)

    Lo, C. F.; Ulbrich, N.

    1992-01-01

    A wall interference assessment and correction method for subsonic two-dimensional wind tunnel testing is presented. This method calculates a pressure coefficient and angle of attack correction based on velocity measurements on interfaces inside of the wind tunnel. A mathematical representation of the test article is not required. An experimental verification of the suggested technique is given. A NACA 0012 airfoil is tested at a Mach number of 0.70 and at two different angles of attack. Calculated blockage corrections show reasonable agreement with results based on Hackett's method. Corrected surface pressures compare favorably to free-air flow field data if the tunnel flow field is subsonic. The present wall interference correction method can be applied to transonic tunnel flow fields with some restrictions. Errors are estimated and it is shown that the expected error in calculating the pressure coefficient correction on the model surface is in the order of the error of pressure coefficient measurement on interfaces. Necessary testing equipment in existing tunnels can easily be modified if the present method is applied.

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

    PubMed Central

    Rosati, R; Rebuffat, C; Pezzuoli, G

    1988-01-01

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

  12. Colloid filtration in surface dense vegetation: experimental results and theoretical predictions.

    PubMed

    Wu, Lei; Muñoz-Carpena, Rafael; Gao, Bin; Yang, Wen; Pachepsky, Yakov A

    2014-04-01

    Understanding colloid and colloid-facilitated contaminant transport in overland flow through dense vegetation is important to protect water quality in the environment, especially for water bodies receiving agricultural and urban runoff. In previous studies, a single-stem efficiency theory for rigid and clean stem systems was developed to predict colloid filtration by plant stems of vegetation in laminar overland flow. Hence, in order to improve the accuracy of the single-stem efficiency theory to real dense vegetation system, we incorporated the effect of natural organic matter (NOM) on the filtration of colloids by stems. Laboratory dense vegetation flow chamber experiments and model simulations were used to determine the kinetic deposition (filtration) rate of colloids under various conditions. The results show that, in addition to flow hydrodynamics and solution chemistry, steric repulsion afforded by NOM layer on the plants stem surface also plays a significant role in controlling colloid deposition on vegetation in overland flow. For the first time, a refined single-stem efficiency theory with considerations of the NOM effect is developed that describes the experimental data with good accuracy. This theory can be used to not only help construct and refine mathematical models of colloid transport in real vegetation systems in overland flow, but also inform the development of theories of colloid deposition on NOM-coated surfaces in natural, engineered, and biomedical systems. PMID:24597773

  13. 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.

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

    SciTech Connect

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

    2003-06-15

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

  15. Magnetic properties of a Kramers doublet. An univocal bridge between experimental results and theoretical predictions

    NASA Astrophysics Data System (ADS)

    Alonso, P. J.; Martínez, J. I.

    2015-06-01

    The magnetic response of a Kramers doublet is analyzed in a general case taking into account only the formal properties derived from time reversal operation. It leads to a definition of a matrix G (gyromagnetic matrix) whose expression depends on the chosen reference frame and on the Kramers conjugate basis used to describe the physical system. It is shown that there exists a reference frame and a suitable Kramers conjugate basis that gives a diagonal form for the G-matrix with all non-null elements having the same sign. A detailed procedure for obtaining this canonical expression of G is presented when the electronic structure of the KD is known regardless the level of the used theory. This procedure provides a univocal way to compare the theoretical predictions with the experimental results obtained from a complete set of magnetic experiments. In this way the problems arising from ambiguities in the g-tensor definition are overcome. This procedure is extended to find a spin-Hamiltonian suitable for describing the magnetic behavior of a pair of weakly coupled Kramers systems in the multispin scheme when the interaction between the two moieties as well as the individual Zeeman interaction are small enough as compared with ligand field splitting. Explicit relations between the physical interaction and the parameters of such a spin-Hamiltonian are also obtained.

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

    NASA Technical Reports Server (NTRS)

    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).

  17. Class E Resonant Regulated DC\\/DC Power Converters: Analysis of Operations, and Experimental Results at 1.5 MHz

    Microsoft Academic Search

    Richard Redl; Bela Molnar; Nathan O. Sokal

    1986-01-01

    Analytical results, design considerations, and experimental results at 1.5 MHz are presented, for a novel resonant high-frequency dc\\/dc converter. The circuit works virtually without dynamic losses at several-MHz switching frequency. The analysis gives the permissible area of the equivalent load impedance for lossless operation, presents a model for regulation by narrow-band frequency control, and characterizes the output full-wave rectifier. Experimental

  18. Energy spectrum of medium energy gamma-rays from the galactic center region. [experimental design

    NASA Technical Reports Server (NTRS)

    Palmeira, R. A. R.; Ramanujarao, K.; Dutra, S. L. G.; Bertsch, D. L.; Kniffen, D. A.; Morris, D. J.

    1978-01-01

    A balloon-borne magnetic core digitized spark chamber with two assemblies of spark-chambers above and below the scintillation counters was used to measure the medium energy gamma ray flux from the galactic center region. Gamma ray calculations are based on the multiple scattering of the pair electrons in 15 aluminum plates interleaved in the spark chamber modules. Counting rates determined during ascent and at ceiling indicate the presence of diffuse component in this energy range. Preliminary results give an integral flux between 15 and 70 MeV compared to the differential points in other results.

  19. On-board four-dimensional digital tomosynthesis: first experimental results.

    PubMed

    Maurer, Jacqueline; Godfrey, Devon; Wang, Zhiheng; Yin, Fang-Fang

    2008-08-01

    The purpose of this study is to propose four-dimensional digital tomosynthesis (4D-DTS) for on-board analysis of motion information in three dimensions. Images of a dynamic motion phantom were reconstructed using acquisition scan angles ranging from 20 degrees (DTS) to full 360 degrees cone-beam computed tomography (CBCT). Projection images were acquired using an on-board imager mounted on a clinical linear accelerator. Three-dimensional (3D) images of the moving target were reconstructed for various scan angles. 3D respiratory correlated phase images were also reconstructed. For phase-based image reconstructions, the trajectory of a radiopaque marker was tracked in projection space and used to retrospectively assign respiratory phases to projections. The projections were then sorted according phase and used to reconstruct motion correlated images. By using two sets of projections centered about anterior-posterior and lateral axes, this study demonstrates how phase resolved coronal and sagittal DTS images can be used to obtain 3D motion information. Motion artifacts in 4D-DTS phase images are compared with those present in four-dimensional CT (4DCT) images. Due to the nature of data acquisition for the two modalities, superior-inferior motion artifacts are suppressed to a greater extent in 4D-DTS images compared with 4DCT. Theoretical derivations and experimental results are presented to demonstrate how optimal selection of image acquisition parameters including the frequency of projection acquisition and the phase window depend on the respiratory period. Two methods for acquiring projections are discussed. Preliminary results indicate that 4D-DTS can be used to acquire valuable kinetic information of internal anatomy just prior to radiation treatment. PMID:18777918

  20. Sediment sorption coefficient measurements for four phthalate esters: Experimental results and model theory

    SciTech Connect

    Williams, M.D.; Adams, W.J. [ABC Laboratories, Columbia, MO (United States); Parkerton, T.F.; Biddinger, G.R. [Exxon Biomedical Sciences, East Millstone, NJ (United States); Robillard, K.A. [Eastman Kodak Co., Rochester, NY (United States)

    1995-09-01

    Sediment partition coefficients were measured for four commercial phthalate esters: dihexyl phthalate (DHP), di(2-ethylhexyl) phthalate (DEHP), diisodecyl phthalate (DIDP), and ditridecyl phthalate (DTDP). The experimental procedure was based on the US Environmental Protection Agency (EPA) test Guideline 796.2750, ``Sediment and Soil Adsorption Isotherm.`` Three sediments were used: EPA 8 (0.15% organic carbon), EPA 18 (0.66% organic carbon), and EPA 21 (1.88% organic carbon). The Freundlich equation was used to calculate organic carbon-normalized sediment/water partition coefficients (K{sub oc}), which averaged 5.26 {times} 10{sup 4} {+-} 4.54 {degree} 10{sup 3}; 4.82 {times} 10{sup 5} {+-} 3.52 {times} 10{sup 5}; 2.86 {times} 10{sup 5} {+-} 2.74 {times} 10{sup 5}; and 1.82 {times} 10{sup 6} {+-} 1.05 {times} 10{sup 6} for DHP, DEHP, DIDP, and DTDP, respectively. In general, these K{sub oc} values did not correlate well to either sediment or chemical properties. This lack of correlation suggested that the measured K{sub oc} values are suppressed, potentially as a function of experimental conditions. On the basis of these data, it was decided to investigate the dependence of K{sub oc} on sediment solids concentration and dissolved organic carbon. Analysis of these and earlier reported partition coefficient data indicated that measured K{sub oc} values for phthalate esters obtained in shake-flask experiments exhibited an inverse dependence on solids concentration. These results were consistent with partitioning models that are discussed. Depending on compound hydrophobicity, the particle-corrected K{sub oc} values were from one to three orders of magnitude higher than the measured K{sub oc} values. Therefore, if partition coefficient values obtained by using Test Guideline 796.2750 or similar shake-flask procedures are not corrected for solids effect, the estimates of the sediment pore-water concentration of the chemical is likely to be overestimated.

  1. 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.

  2. 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.

  3. Recent PHENIX Results from the RHIC Energy Scan

    NASA Astrophysics Data System (ADS)

    O'Brien, Edward

    2013-05-01

    The PHENIX experiment has analyzed data produced in beam energy scans performed by the Relativistic Heavy Ion Collider at Brookhaven National Laboratory, that cover an energy range of ?{sNN}=7.7 GeV to 200 GeV. Analyses search for signatures of the onset of sQGP formation and the QCD critical point by examining the evolution of event characteristics versus centrality as ?{sNN} is varied. Results from excitation studies of global variables and their fluctuations, parton energy loss, J/?RAA and anisotropic flow are presented.

  4. Review of Recent Results from the RHIC Beam Energy Scan

    E-print Network

    Kumar, Lokesh

    2013-01-01

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

  5. Experimental determination of the energy dependence of defect production

    NASA Astrophysics Data System (ADS)

    Merkle, K. L.; King, Wayne E.; Baily, A. C.; Haga, K.; Meshii, M.

    1983-07-01

    A knowledge of primary damage production as a function of recoil energy is essential for predicting defect production in radiation environments of practical interest. The damage function ?(T), i.e., the number of Frenkel pairs as a function of recoil energy, is determined for Cu from electron and ion damage-rate measurements. ?(T) shows a plateau at ? = 0.54 which extends up to ~ 7T dmin. Therefore, simple damage models, such as the modified Kinchin-Pease expression, are strongly deficient, not only at high recoil energies where stimulated recombination in cascades reduces defect production, but also in the single displacement regime. As a consequence, no simple relation between T dmin and T dav is expected to exist. A procedure is suggested which uses anisotropy measurements in combination with polycrystal electron and ion irradiations to construct absolute damage functions in metals.

  6. Experimental valitation of energy harvesting device for civil engineering applications

    NASA Astrophysics Data System (ADS)

    Jung, Hyung-Jo; Kim, In-Ho; Park, Jeongsu

    2012-04-01

    In the field of structural health monitoring using wireless sensors, considerable research attention has been recently given to vibration-based energy harvesting devices for exploring their feasibility as a power source of a wireless sensor node. Most of the previous studies have focused on lab-scale tests for performance validation. For real application, however, field tests on developed energy harvesting devices should be conducted, because their performance may be considerably affected by change in the testing environment. In this study, a new electromagnetic energy harvester is proposed, which is more suitable for civil engineering application, and the preliminary field test on a real cable-stayed bridge are conducted to validate its effectiveness.

  7. 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.

  8. Ion surfing: a new mode for cryogenic gas catchers, experimental results

    NASA Astrophysics Data System (ADS)

    Brodeur, Maxime; Bollen, Georg; Gehring, Amanda; Morrissey, David; Pang, Gregory

    2011-10-01

    A new mode of ion-transport and collection for low-energy precision experiments at projectile fragmentation facilities was recently proposed by Bollen. Present beam thermalization methods use gas-filled linear chambers equipped with sets of electrodes that provide an electrostatic gradient and/or alternating electric fields to transport the ions towards an extraction orifice. A new cryogenic linear gas cell of the National Superconducting Cyclotron Laboratory at Michigan State University will transport ions using only electrodynamic RF fields imposed on a series of linear conductive stripes. Traditionally, the ions migrate along a descending electrostatic potential gradient applied on the individual stripes, called the drag field, which requires a large potential difference to be applied in the gas for transport over long distances. The new method to transport the ions, called ``ion surfing,'' replaces the drag field with a traveling wave. The new method can transport ions at greater speed while simplifying the overall system. We will present the results of recent measurements for the transport of 85-Rb ions over distances up to 40 cm with various gas pressures at room temperature. US Department of Energy and the US National Science Foundation.

  9. 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.

  10. 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.

  11. EXPERIMENTAL RESULTS ON TRAPPING A GUN PLASMA IN TORMAC P-l

    SciTech Connect

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

    1981-07-01

    A start-up scheme for producing a plasma in the biscusp field configuration of TORMAC which involves the radial injection and trapping of a toroidal gun plasma is described. The peloidal field of the external cusp coils acts as a barrier to the outward travel of the plasma ring. Interferometry and magnetic probe measurements observed the stopping of the expanding plasma ring which has a velocity of 17 cm/{micro}sec. Once stopped, the fields are arranged to hold the plasma in a magnetic well. Interferometry measurements observed a well defined outer boundary remaining stationary during the 20 {micro}sec of the measurement. The inner boundary was also in evidence as shown particularly by the particle flux distribution emanating from the cusp region. The indications are that a sheath exists having a width of 1 to 1.5 ion gyro radii in the poloidial field. Measurements of Thomson 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.

  12. Monitoring the oxygen transfer efficiency of full-scale aeration systems: investigation method and experimental results.

    PubMed

    Gori, Riccardo; Balducci, Alice; Caretti, Cecilia; Lubello, Claudio

    2014-01-01

    This paper reports the results of a series of off-gas tests aimed at monitoring the evolution of the oxygen transfer efficiency in an urban wastewater treatment plant (3,500 population equivalent) located in Tuscany (Italy). The tests were conducted over a 2-year period starting with the testing of the aeration system. It was found that in the absence of membrane-panel cleaning operations, the oxygen transfer efficiency under standard conditions in process water (?SOTE) dropped from 18 to 9.5% in 2 years. This gives rise to a 40% increase in the wastewater treatment plant annual energy costs. The on-site chemical cleaning of the diffusers allowed for an almost total recovery of the transfer efficiency (?SOTE equal to 16%). The use of the off-gas method for monitoring the oxygen transfer efficiency over time is therefore essential for enabling correct planning of the cleaning operations of the diffusers and for cutting the energy consumption and operating costs of the aeration system. PMID:25026573

  13. Results of experimental and theoretical investigations in charge transfer transitions, scintillators and Eu 2+ based phosphors

    NASA Astrophysics Data System (ADS)

    Srivastava, Alok M.

    2009-11-01

    A brief overview of recent results obtained in scintillator and phosphors are presented. Four topics, that are at the center of considerable research, and which are important from both fundamental and practical point of view, are chosen. The identification and behavior of ligand-to-RE 3+ (RE 3+ = rare earth) charge transfer transition when the ligand ions are halides and N 3- is reviewed. The reasons for the high light yield of the LuI 3:Ce 3+ scintillator is investigated theoretically and a new channel of energy transfer to excitons and directly to the Ce 3+ ion identified. The prospect of increasing the light yield of Ce 3+ based scintillators by the Pr 3+ ion is discussed. Finally, the remarkable luminescence of octahedrally coordinated Eu 2+ ion in Cs 2M 2+P 2O 7 (M 2+ = Ca, Sr) is discussed.

  14. ATLAS Post-doctoral Research Associate Position in Experimental High Energy Physics

    E-print Network

    ATLAS Post-doctoral Research Associate Position in Experimental High Energy Physics York University interests, and arrange to have three letters of reference sent by post to: Dr. Wendy Taylor Department

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

    E-print Network

    Gruber, Timothy J. (Timothy James)

    2012-01-01

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

  16. Experimental Method to Determine the Energy Envelope Performance of Buildings 

    E-print Network

    Berger, J.; Tasca-Guernouti, S. T.; Humbert, M.

    2010-01-01

    (Purchasing, laboratory, slight industry) 93 1.6 Moderate activity, standing up (sale, housework , work on machines) 116 2.0 Walking with 2km/h speed 110 1.9 Figure 4. The metabolism energy production (NF EN ISO 7730, 2006) 1 The unit... of the metabolism energy production is the met. One met corresponds to the metabolism of one person at rest and valued 58.2 W/m? per corporal unit surface, knowing that the rate of corporal surface is 1.8 m? for pa person. The internal gain due to electric...

  17. Equation Section 1Structure of Downward Spreading Flames: A Comparison of Numerical Simulation, Experimental Results and a Simplified Parabolic Theory

    Microsoft Academic Search

    Subrata Bhattacharjee; Matthew D. King; Chris Paolini

    Temperature and velocity fields in a downward flame spread over flat solid fuels in a gravitational field are numerically simulated and compared with available experimental measurements and a simplified theory. The two-dimensional steady numerical model solves the mass, energy, species-mass, and momentum equations in the gas phase and the energy equation in the solid phase and includes gas-phase and pyrolysis

  18. Structure of downward spreading flames: a comparison of numerical simulation, experimental results and a simplified parabolic theory

    Microsoft Academic Search

    Subrata Bhattacharjee; Matthew D. King; Chris Paolini

    2004-01-01

    Temperature and velocity fields in a downward flame spread over flat, solid fuels in a gravitational field are numerically simulated and compared with available experimental measurements and a simplified theory. The two-dimensional steady numerical model solves the mass, energy, species-mass, and momentum equations in the gaseous phase and the energy equation in the solid phase and includes gas-phase and pyrolysis

  19. 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.

  20. Unfolding linac photon spectra and incident electron energies from experimental transmission data, with direct independent validation

    SciTech Connect

    Ali, E. S. M.; McEwen, M. R.; Rogers, D. W. O. [Carleton Laboratory for Radiotherapy Physics, Department of Physics, Carleton University, 1125 Colonel By Drive, Ottawa, Ontario K1S 5B6 (Canada); Ionizing Radiation Standards, Institute for National Measurement Standards, National Research Council, M-35 Montreal Road, Ottawa, Ontario K1A 0R5 (Canada); Carleton Laboratory for Radiotherapy Physics, Department of Physics, Carleton University, 1125 Colonel By Drive, Ottawa, Ontario K1S 5B6 (Canada)

    2012-11-15

    Purpose: In a recent computational study, an improved physics-based approach was proposed for unfolding linac photon spectra and incident electron energies from transmission data. In this approach, energy differentiation is improved by simultaneously using transmission data for multiple attenuators and detectors, and the unfolding robustness is improved by using a four-parameter functional form to describe the photon spectrum. The purpose of the current study is to validate this approach experimentally, and to demonstrate its application on a typical clinical linac. Methods: The validation makes use of the recent transmission measurements performed on the Vickers research linac of National Research Council Canada. For this linac, the photon spectra were previously measured using a NaI detector, and the incident electron parameters are independently known. The transmission data are for eight beams in the range 10-30 MV using thick Be, Al and Pb bremsstrahlung targets. To demonstrate the approach on a typical clinical linac, new measurements are performed on an Elekta Precise linac for 6, 10 and 25 MV beams. The different experimental setups are modeled using EGSnrc, with the newly added photonuclear attenuation included. Results: For the validation on the research linac, the 95% confidence bounds of the unfolded spectra fall within the noise of the NaI data. The unfolded spectra agree with the EGSnrc spectra (calculated using independently known electron parameters) with RMS energy fluence deviations of 4.5%. The accuracy of unfolding the incident electron energy is shown to be {approx}3%. A transmission cutoff of only 10% is suitable for accurate unfolding, provided that the other components of the proposed approach are implemented. For the demonstration on a clinical linac, the unfolded incident electron energies and their 68% confidence bounds for the 6, 10 and 25 MV beams are 6.1 {+-} 0.1, 9.3 {+-} 0.1, and 19.3 {+-} 0.2 MeV, respectively. The unfolded spectra for the clinical linac agree with the EGSnrc spectra (calculated using the unfolded electron energies) with RMS energy fluence deviations of 3.7%. The corresponding measured and EGSnrc-calculated transmission data agree within 1.5%, where the typical transmission measurement uncertainty on the clinical linac is 0.4% (not including the uncertainties on the incident electron parameters). Conclusions: The approach proposed in an earlier study for unfolding photon spectra and incident electron energies from transmission data is accurate and practical for clinical use.

  1. Experimental and numerical measurements of adhesion energies between PHEMA and PGLYMA with hydroxyapatite crystal.

    PubMed

    Youssefian, Sina; Liu, Pingsheng; Askarinejad, Sina; Shalchy, Faezeh; Song, Jie; Rahbar, Nima

    2015-01-01

    Synthetic orthopaedic materials consisting of a single bioinert polymeric material do not meet the complex biological and physical requirements of scaffold-guided bone tissue repair and regeneration. Of particular interest is the design of biocompatible hydrogel-hydroxyapatite composite bone substitutes with outstanding interfacial adhesion that would warranty the ability for the composite to withstand functional loadings without exhibiting brittle fractures during the dynamic guided tissue regeneration. For this purpose, the hydroxylated side chain of chemically cross-linked poly (2-hydroxyethyl methacrylate) (pHEMA) is substitute with a carboxylated side chain to make poly (glycerol methacrylate) (pGLYMA). Here, we carry out atomistic simulations and atomic force microscopy to predict and experimentally determine the interfacial adhesion energies of pHEMA and pGLYMA with the surface of single-crystalline hydroxyapatite (HA) whiskers. Both experimental and numerical results showed that pGLYMA has stronger adhesion forces with HA and may be used for preparing a high-affinity polymer-HA composite. The high adhesive interactions between pGLYMA and HA were found to be due to strong electrostatic energies. PMID:26179911

  2. Experimental Vibrational Zero-Point Energies: Diatomic Molecules

    Microsoft Academic Search

    Karl K. Irikura

    2007-01-01

    Vibrational zero-point energies (ZPEs), as determined from published spectroscopic constants, are derived for 85 diatomic molecules. Standard uncertainties are also provided, including estimated contributions from bias as well as the statistical uncertainties propagated from those reported in the spectroscopy literature. This compilation will be helpful for validating theoretical procedures for predicting ZPEs, which is a necessary step in the ab

  3. Piezoelectric Energy Harvesting with a Clamped Circular Plate: Experimental Study

    Microsoft Academic Search

    Sunghwan Kim; William W. Clark; Qing-Ming Wang

    2005-01-01

    In a companion article, a model for a clamped circular unimorph piezoelectric plate has been developed for the purpose of analyzing the influence of geometric design parameters and electrode configuration on the amount of electrical energy that can be harvested from an applied pressure source. It has been shown that the ratio of layer thickness (piezoelectric layer to substrate layer)

  4. Molecular dynamics simulations of human carbonic anhydrase II: insight into experimental results and the role of solvation.

    PubMed

    Lu, D; Voth, G A

    1998-10-01

    In this paper, the carbonic anhydrase II (CA II) enzyme active site is modeled using ab initio calculations and molecular dynamics simulations to examine a number of important issues for the enzyme function. It is found that the Zn2+ ion is dominantly tetrahedrally coordinated, which agrees with X-ray crystallographic studies. However, a transient five-fold coordination with an extra water molecule is also found. Studies of His64 conformations upon a change in the protonation states of the Zn-bound water and the His64 residue also confirm the results of an X-ray study which suggest that the His64 conformation is quite flexible. However, the degree of water solvation is found to affect this behavior. Water bridge formation between the Zn-bound water and the His64 residue was found to involve a free energy barrier of 2-3 kcal/mol and an average lifetime of several picoseconds, which supports the concept of a proton transfer mechanism through such a bridge. Mutations of various residues around the active site provide further insight into the corresponding experimental results and, in fact, suggest an important role for the solvent water molecules in the CA II catalytic mechanism. PMID:9741850

  5. 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.

  6. 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, J.-F.; Mengelkamp, H.-T.; Mitchell, K.; Nasonova, O.N.; Noilhan, J.; Robock, A.; Rosenzweig, C.; Schaake, J.; Schlosser, C.A.; Schulz, J.-P.; Shao, Y.; Shmakin, A.B.; Verseghy, D.L.; Wetzel, P.; Wood, E.F.; Xue, Y.; Yang, Z.-L.; Zeng, Q.

    1997-01-01

    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.

  7. Experimental balance energies and isospin-dependent nucleon-nucleon cross-sections

    E-print Network

    Sanjeev Kumar; Rajni; Suneel Kumar

    2010-09-28

    The effect of different isospin-dependent cross-section on directed flow is studied for variety of systems(for which experimental balance energies are available) using an isospin-dependent Quantum Molecular Dynamic (IQMD) model. We show that balance energies are sensitive towards isospin-dependent cross-sections for light systems, while nearly no effect exist for heavier nuclei. A reduced cross-section $\\sigma = 0.9\\sigma_{NN}$ with stiff equation of state is able to explain experimental balance energies in most of systems. A power law behaviour is also given for the mass dependence of balance energy, which also follow N/Z dependence.

  8. Experimental balance energies and isospin-dependent nucleon-nucleon cross-sections

    E-print Network

    Kumar, Sanjeev; Kumar, Suneel

    2010-01-01

    The effect of different isospin-dependent cross-section on directed flow is studied for variety of systems(for which experimental balance energies are available) using an isospin-dependent Quantum Molecular Dynamic (IQMD) model. We show that balance energies are sensitive towards isospin-dependent cross-sections for light systems, while nearly no effect exist for heavier nuclei. A reduced cross-section $\\sigma = 0.9\\sigma_{NN}$ with stiff equation of state is able to explain experimental balance energies in most of systems. A power law behaviour is also given for the mass dependence of balance energy, which also follow N/Z dependence.

  9. Experimental balance energies and isospin-dependent nucleon-nucleon cross-sections

    SciTech Connect

    Kumar, Sanjeev; Rajni; Kumar, Suneel [School of Physics and Materials Science, Thapar University, Patiala 147004, Punjab (India)

    2010-08-15

    The effect of different isospin-dependent cross-sections on directed flow is studied for a variety of systems (for which experimental balance energies are available) using an isospin-dependent quantum molecular dynamic (IQMD) model. We show that balance energies are sensitive toward isospin-dependent cross sections for light systems, while nearly no effect exists for heavier nuclei. A reduced cross-section {sigma}=0.9{sigma}{sub NN} with stiff equation of state is able to explain experimental balance energies in most of systems. A power law behavior is also given for the mass dependence of balance energy, which also follows the N/Z dependence.

  10. A Summary of Recent Experimental Research on Ion Energy and Charge States of Pulsed Vacuum Arcs

    SciTech Connect

    Oks, Efim M.; Yushkov, Georgy Yu.; Anders, Andre

    2008-06-16

    The paper reviews the results of vacuum arc experimental investigations made collaboratively by research groups from Berkeley and Tomsk over the last two years, i.e. since the last ISDEIV in 2006. Vacuum arc plasma of various metals was produced in pulses of a few hundred microseconds duration, and the research focussed on three topics: (i) the energy distribution functions for different ion charge states, (ii) the temporal development of the ion charge state distribution, and (iii) the evolution of the mean directed ion velocities during plasma expansion. A combined quadruple mass-to-charge and energy ana-lyzer (EQP by HIDEN Ltd) and a time-of-flight spectrometer were employed. Cross-checking data by those complimen-tary techniques helped to avoid possible pitfalls in interpre-tation. It was found that the ion energy distribution func-tions in the plasma were independent of the ion charge state, which implies that the energy distribution on a substrate are not equal to due to acceleration in the substrate's sheath. In pulsed arc mode, the individual ion charge states fractions showed changes leading to a decrease of the mean charge state toward a steady-state value. This decrease can be re-duced by lower arc current, higher pulse repetition rate and reduced length of the discharge gap. It was also found that the directed ion velocity slightly decreased as the plasma expanded into vacuum.

  11. Experimental determination of the energy dependence of defect production

    SciTech Connect

    Merkle, K.L.; King, W.E.; Baily, A.C.; Haga, K.; Meshii, M.

    1982-01-01

    The damage function nu(T), i.e., the number of Frenkel pairs as a function of recoil energy is determined for Cu from electron and ion damage-rate measurements. nu(T) shows a plateau at nu = 0.54 which extends up to approx. 7xT/sub d//sup min/. Therefore, simple damage models, such as the modified Kinchin-Pease expression, are inappropriate not only at high recoil energies where stimulated recombination in cascades reduces defect production, but also in the single displacement regime. As a consequence, no simple relation between T/sub d//sup min/ and T/sub d//sup av/ is expected to exist. A procedure is suggested which uses anisotropy measurements in combination with polycrystal electron and ion irradiations to construct absolute damage functions in metals.

  12. Marine pollution network euromar-mermaid: Results of the experimental operation

    NASA Astrophysics Data System (ADS)

    Knauth, H.-D.; Schroeder, F.; Menzel, R.; Gebhart, E.; Marx, S.; Kohnke, D.; Holzkamm, F.; Nies, H.; Theobald, N.

    1997-09-01

    The need for automated systems to monitor chemical and biochemical variables led to the definition of the EUREKA-EUROMAR project MERMAID. It was realized by several international scientific and industrial partners. Important components were automatic nutrient analyzers and remote-controlled samplers for toxic trace substances in addition to a high-performance data management system with bi-directional telemetry units for remote-controlled network operation. These modules were implemented in the MERMAID network consisting of three sea stations, two of them set up in the Elbe estuary, and one in the Elbe-influenced coastal zone. The latter was at the same time part of the BSH-network. The data were transmitted to shore and processed at GKSS and BSH. While in the preceding project phase the marine pollution network was established and tested, the last MERMAID phase covered its experimental operation. For this purpose, different modules were installed at the three stations. They incorporated meteorological, oceanographic, physical and chemical sensors in addition to automatic analyzers for phosphate, nitrite/nitrate and ammonium as well as specialized samplers for heavy metals and organic micropollutants. Variables were determined directly either continuously by in situ sensors or at variable time intervals by remote-controlled in situ analyzers, or they were determined indirectly by samplers allowing phase-separated multiple sampling with remote or event control of the sampling frequency. In this contribution, the results of nutrient and heavy metal concentration time series measured in 1995 and 1996 are presented together with corresponding meteorological and oceanographic variables. The examples indicate that the transfer of nutrients and contaminants in the estuary and in the coastal zone is strongly influenced by different short- and long-term events, i.e. freshwater discharge rates and wind action. Additionally, in summer, chemical and biological processes influence the fate of these substances on their way from the river to the coastal zone to a high degree. The present results and some earlier findings allow the conclusion that the existing monitoring procedures should be supplemented by new measuring methods. This can be accomplished by means of strategically placed fixed stations at which continuous, short-interval measurements of chemically and biologically relevant parameters are carried out. To cut down laboratory costs for trace analyses, the automated sampling should be ‘intelligent’ and event-controlled.

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

    SciTech Connect

    Avicola, K.; Brase, J.; Morris, J. [and others

    1994-03-02

    The architecture and major system components of the sodium-layer kw guide star system at LLNL will be described, and experimental results reported. The subsystems include the laser system, the beam delivery system including a pulse stretcher and beam pointing control, the beam director, and the telescope with its adaptive-optics package. The laser system is one developed for the Atomic Vapor Laser Isotope Separation (AVLIS) Program. This laser system can be configured in various ways in support of the AVLIS program objectives, and was made available to the guide star program at intermittent times on a non-interference basis. The first light transmitted into the sky was in July of 1992, at a power level of 1. 1 kW. The laser pulse width is about 32 ns, and the pulse repetition rate was 26 kHz for the 1. 1 kW configuration and 13 kHz for a 400 W configuration. The laser linewidth is tailored to match the sodium D{sub 2} absorption line, and the laser system has active control of beam pointing and wavefront quality. Because of the short pulse length the sodium transition is saturated and the laser power is not efficiently utilized. For this reason a pulse stretcher was developed, and the results of this effort will be reported. The beam is delivered via an evacuated pipe from the laser building to the guide star site, a distance of about 100 meters, and then launched vertically. A beam director provides the means to track the sky in the full AO system, but was not used in the experiments reported here. The return signal is collected by a 1/2 meter telescope with the AO package. This telescope is located 5 meters from the km launch tube. Smaller packages for photometry, wavefront measurement, and spot image and motion analysis have been used. Although the unavailability of the AVLIS laser precluded a full AO system demonstration, data supporting feasibility and providing input to the system design for a Lick Observatory AO system was obtained.

  14. 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.

  15. Ozone production in the reaction of Tâ and Oâ gas: A comparison of experimental results and model predictions

    Microsoft Academic Search

    R. A. Failor; P. C. Souers; F. Magnotta

    1992-01-01

    Ozone, predicted to be an important intermediate species in Tâ oxidation, was monitored in situ by UV absorption spectroscopy for 0.01-1.0 mol % Tâ in Oâ (1 atm, 298 K). These are the first measurements of a tritium oxidation reaction intermediate. The experimental results were compared with the predictions of the author`s comprehensive model of tritium oxidation. The experimentally determined

  16. Experimental ocean acidification alters the allocation of metabolic energy

    PubMed Central

    Pan, T.-C. Francis; Applebaum, Scott L.; Manahan, Donal T.

    2015-01-01

    Energy is required to maintain physiological homeostasis in response to environmental change. Although responses to environmental stressors frequently are assumed to involve high metabolic costs, the biochemical bases of actual energy demands are rarely quantified. We studied the impact of a near-future scenario of ocean acidification [800 µatm partial pressure of CO2 (pCO2)] during the development and growth of an important model organism in developmental and environmental biology, the sea urchin Strongylocentrotus purpuratus. Size, metabolic rate, biochemical content, and gene expression were not different in larvae growing under control and seawater acidification treatments. Measurements limited to those levels of biological analysis did not reveal the biochemical mechanisms of response to ocean acidification that occurred at the cellular level. In vivo rates of protein synthesis and ion transport increased ?50% under acidification. Importantly, the in vivo physiological increases in ion transport were not predicted from total enzyme activity or gene expression. Under acidification, the increased rates of protein synthesis and ion transport that were sustained in growing larvae collectively accounted for the majority of available ATP (84%). In contrast, embryos and prefeeding and unfed larvae in control treatments allocated on average only 40% of ATP to these same two processes. Understanding the biochemical strategies for accommodating increases in metabolic energy demand and their biological limitations can serve as a quantitative basis for assessing sublethal effects of global change. Variation in the ability to allocate ATP differentially among essential functions may be a key basis of resilience to ocean acidification and other compounding environmental stressors. PMID:25825763

  17. Experimental ocean acidification alters the allocation of metabolic energy.

    PubMed

    Pan, T-C Francis; Applebaum, Scott L; Manahan, Donal T

    2015-04-14

    Energy is required to maintain physiological homeostasis in response to environmental change. Although responses to environmental stressors frequently are assumed to involve high metabolic costs, the biochemical bases of actual energy demands are rarely quantified. We studied the impact of a near-future scenario of ocean acidification [800 µatm partial pressure of CO2 (pCO2)] during the development and growth of an important model organism in developmental and environmental biology, the sea urchin Strongylocentrotus purpuratus. Size, metabolic rate, biochemical content, and gene expression were not different in larvae growing under control and seawater acidification treatments. Measurements limited to those levels of biological analysis did not reveal the biochemical mechanisms of response to ocean acidification that occurred at the cellular level. In vivo rates of protein synthesis and ion transport increased ?50% under acidification. Importantly, the in vivo physiological increases in ion transport were not predicted from total enzyme activity or gene expression. Under acidification, the increased rates of protein synthesis and ion transport that were sustained in growing larvae collectively accounted for the majority of available ATP (84%). In contrast, embryos and prefeeding and unfed larvae in control treatments allocated on average only 40% of ATP to these same two processes. Understanding the biochemical strategies for accommodating increases in metabolic energy demand and their biological limitations can serve as a quantitative basis for assessing sublethal effects of global change. Variation in the ability to allocate ATP differentially among essential functions may be a key basis of resilience to ocean acidification and other compounding environmental stressors. PMID:25825763

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

    NASA Astrophysics Data System (ADS)

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

    2014-11-01

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

  19. Planned experimental studies on natural-circulation and stability performance of boiling water reactors in four experimental facilities and first results (NACUSP)

    Microsoft Academic Search

    W. J. M de Kruijf; K. C. J Ketelaar; G Avakian; P Gubernatis; D Caruge; A Manera; T. H. J. J Van der Hagen; G Yadigaroglu; G Dominicus; U Rohde; H.-M Prasser; F Castrillo; M Huggenberger; D Hennig; J. L Munoz-Cobo; C Aguirre

    2003-01-01

    Within the 5th Euratom framework programme the NACUSP project focuses on natural-circulation and stability characteristics of Boiling Water Reactors (BWRs). This paper gives an overview of the research to be performed. Moreover, it shows the first results obtained by one of the four experimental facilities involved. Stability boundaries are given for the low-power low-pressure operating range, measured in the CIRCUS

  20. 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.

  1. Surface composition of ternary cu-ag-au alloys: part i. experimental results

    Microsoft Academic Search

    M. A. Hoffmann; P. Wynblatt

    1991-01-01

    The enthalpies and entropies of segregation for silver and gold, along with equilibrium surface composition measurements on\\u000a three Cu-Ag-Au ternary specimens, are reported and discussed. The experimentally studied compositions were Cu-0.3 at. pct\\u000a Ag-2.1 at. pct Au, Cu-0.55 at. pct Ag-6.5 at. pct Au, and Cu-1.09 at. pct Ag-6.9 at. pct Au. The experimental enthalpies of\\u000a segregation, entropies of segregation,

  2. THE INFLUENCE OF SYMBOLIC AND GRAPHICAL LANGUAGE MANIPULATIONS ON ANSWERS TO SELF-ADMINISTERED QUESTIONNAIRES: RESULTS FROM 14 EXPERIMENTAL COMPARISONS

    Microsoft Academic Search

    Leah M. Christian; Don A. Dillman

    This paper reports results from 14 experimental comparisons designed to test 7 hypotheses about the effects of two types of nonverbal languages (symbols and graphics) on responses to self- administered questionnaires. The experiments were included in a large-scale survey of 1,042 university students. Significant differences were observed for most comparisons, providing support for all seven hypotheses. These results confirm that

  3. Flight Test Results of a Thermoelectric Energy Harvester for Aircraft

    NASA Astrophysics Data System (ADS)

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

    2012-06-01

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

  4. Experimental Free Energy Surface Reconstruction From Single-Molecule Force Spectroscopy Using Jarzynski's Equality

    E-print Network

    Nolan C. Harris; Yang Song; Ching-Hwa Kiang

    2007-07-03

    We used the atomic force microscope to manipulate and unfold individual molecules of the titin I27 domain and reconstructed its free energy surface using Jarzynski's equality. The free energy surface for both stretching and unfolding was reconstructed using an exact formula that relates the nonequilibrium work fluctuations to the molecular free energy. In addition, the unfolding free energy barrier, i.e. the activation energy, was directly obtained from experimental data for the first time. This work demonstrates that Jarzynski's equality can be used to analyze nonequilibrium single-molecule experiments, and to obtain the free energy surfaces for molecular systems, including interactions for which only nonequilibrium work can be measured.

  5. Homestake result, sterile neutrinos, and low energy solar neutrino experiments

    Microsoft Academic Search

    P. C. de Holanda; A. Yu. Smirnov

    2004-01-01

    The Homestake result is about ~ 2 \\\\sigma lower than the Ar-production rate,\\u000aQ_{Ar}, predicted by the LMA MSW solution of the solar neutrino problem. Also\\u000athere is no apparent upturn of the energy spectrum (R \\\\equiv N_{obs}\\/N_{SSM})\\u000aat low energies in SNO and Super-Kamiokande. Both these facts can be explained\\u000aif a light, \\\\Delta m^2_{01} ~ (0.2 - 2)

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

    NASA Astrophysics Data System (ADS)

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

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

  7. High energy experimental physics. Progress report and renewal proposal

    SciTech Connect

    Rosen, J.; Miller, D.

    1985-01-01

    Technical progress is summarized for activities in these areas: study of charm particle production in hadronic collisions (data analysis); large-aperture multiparticle spectrometer; TEV I debuncher ring profile monitor; beta source monochromatizer; final reduction of data from pp and p anti p elastic scattering; high energy elastic scattering and cross section review; consequences of the Auberson-Kinoshita-Martin theorem for the nuclear slope parameter; planning and final design of the elastic scattering and total cross section experiment at the Tevatron Collider; a D-zero pp project and photoproduction experiment; lepton production in heavy-ion collisions; prompt gamma and massive lepton-pair production apparatus; and spin physics with the Fermilab polarized beam facility. (LEW)

  8. Experimental analysis of survey response bias over the internet: Some results from the Retirement Perspectives Survey

    Microsoft Academic Search

    Daniel McFadden; Joachim Winter

    There is overwhelming empirical evidence that cognitive limitations and social interac- tions lead to biases in responses to survey questions. In addition, there is evidence that some of the underlying processes are moderated by age. The purpose of the Berkeley Internet Virtual Labora- tory (IVLab) is to study these phenomena using experimental surveys conducted over the internet. The internet is

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

    Microsoft Academic Search

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

    2010-01-01

    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

  10. Circular polarization filters made of chiral sculptured thin films: experimental and simulation results

    Microsoft Academic Search

    Qihong Wu; Ian J. Hodgkinson; Akhlesh Lakhtakia

    2000-01-01

    Thin-film helicoidal bianisotropic medium (TFHBM) layers with large local linear birefringence are fabricated using the serial bideposition technique. The viability of axially excited TFHBM layers as circular polarization filters is experimentally demonstrated. The presence of index-matched cover and substrate media is shown to enhance the filter performance of a TFHBM layer. A thinner TFHBM layer is required for adequate performance

  11. Adsorption of Monovalent Organic Cations on Sepiolite: Experimental Results and Model Calculations

    Microsoft Academic Search

    Giora Rytwo; SHLOMO NIR; LEON MARGULIES; BLANCA CASAL; JESUS MERINO; EDUARDO RUIZ-HITZKY; JOSE MARIA SERRATOSA

    1998-01-01

    Adsorption of neutral organic molecules and the monovalent organic cations methylene blue (MB) and crystal violet (CV) to sepiolite was determined experimentally and investigated by an adsorption model. The largest amounts of MB and CV adsorbed were about 4-fold of the cation exchange capacity (CEC) of sepiolite. Consequently, it was proposed that most of the above described adsorption was to

  12. Experimental results of cross-site exchange of web content Anomaly Detector alerts

    Microsoft Academic Search

    Nathaniel Boggs; Sharath Hiremagalore; Angelos Stavrou; Salvatore J. Stolfo

    2010-01-01

    We present our initial experimental findings from the collaborative deployment of network Anomaly Detection (AD) sensors. Our system examines the ingress http traffic and correlates AD alerts from two administratively disjoint domains: Columbia University and George Mason University. We show that, by exchanging packet content alerts between the two sites, we can achieve zero-day attack detection capabilities with a relatively

  13. A model-farm approach to research on crop-livestock integration — II. Experimental results

    Microsoft Academic Search

    Euan F. Thomson; Faik A. Bahhady

    1995-01-01

    A six-year project was conducted to show how better crop-livestock integration and improved management increase the outputs of crops and sheep products. Three farm types were compared, consisting of different crop and sheep enterprise mixes, together with natural pastures. The conceptual framework and experimental methods used were reported in a previous paper. This paper reports the crop and sheep enterprise

  14. Oxygen-enriched diesel engine performance; A comparison of analytical and experimental results

    Microsoft Academic Search

    R. R. Sekar; W. W. Marr; T. J. Marciniak; R. L. Cole; D. N. Assanis; J. E. Schaus

    1991-01-01

    Use of oxygen-enriched combustion air in diesel can lead to significant improvements in power density, as well as reduction in particulate emissions, but at the expense of higher NOâ emissions. Oxygen enrichment would also lead to lower ignition delays and the opportunity to burn lower grade fuels. Analytical and experimental studies are being conducted in parallel to establish the optimal

  15. Oxygen-enriched diesel engine performance: A comparison of analytical and experimental results

    Microsoft Academic Search

    R. R. Sekar; W. W. Marr; R. L. Cole; T. J. Marciniak; D. N. Assanis; J. E. Schaus

    1990-01-01

    Use of oxygen-enriched combustion air in diesel engines can lead to significant improvements in power density, as well as reductions in particulate emissions, but at the expense of higher NOâ emissions. Oxygen enrichment would also lead to lower ignition delays and the opportunity to burn lower grade fuels. Analytical and experimental studies are being conducted in parallel to establish the

  16. Experimental Results and Analysis for Adsorption Ice-Making System with Consolidated Adsorbent

    Microsoft Academic Search

    S. G. Wang; R. Z. Wang; J. Y. WUAND; Y. X. Xu

    2003-01-01

    An adsorption ice-making machine has been built with a single consolidated adsorber and activated carbon-methanol pair. A consolidated adsorbent block made of activated carbon mixed with a binder with good heat transfer properties has been developed and implemented in the adsorber. The design is focused on the adsorber consisting of copper finned tubes and carbon blocks. Experimental tests have been

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

    E-print Network

    Srinivasan, Palanivel Rajan

    2000-01-01

    with my research at various times. Luben Todorovski helped me with his data sets and explained his experimental study. His help is greatly appreciated. Samuel Young-Gameros and Anil Ayalasomayajula helped me immensely with ABAQUS and PATRAN. I am very...

  18. Heat transfer to unfrosted wind convectors; Mathematical modeling and comparison with experimental results

    Microsoft Academic Search

    D. P. Finn; P. F. Monaghan; P. H. Oosthuizen

    1990-01-01

    Wind convectors are an alternative air source evaporator system for heat pumps. This paper describes a mathematical model that calculates the heat transfer to wind convectors when forced convection conditions prevail and when wind convector surface frost and rainfall are absent. The mathematical model is validated and predicts heat transfer to within 8 percent of experimental data based on a

  19. Experimental determination of in situ utilization of lunar regolith for thermal energy storage

    Microsoft Academic Search

    Scott W. Richter

    1992-01-01

    A Lunar Thermal Energy from Regolith (LUTHER) experiment has been designed and fabricated at the NASA Lewis Research Center to determine the feasibility of using lunar soil as thermal energy storage media. The experimental apparatus includes an alumina ceramic canister which contains simulated lunar regolith, a heater, nine heat shields, a heat transfer cold jacket, and 19 type-B platinum rhodium

  20. Experimental determination of in situ utilization of lunar regolith for thermal energy storage

    Microsoft Academic Search

    Scott W. Richter

    1993-01-01

    A Lunar Thermal Energy from Regolith (LUTHER) experiment has been designed and fabricated at the NASA Lewis Research Center to determine the feasibility of using lunar soil as thermal energy storage media. The experimental apparatus includes an alumina ceramic canister (25.4 cm diameter by 45.7 cm length) which contains simulated lunar regolith, a heater (either radiative or conductive), 9 heat

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

    E-print Network

    Caragiannis, Ioannis

    Experimental Comparison of Algorithms for Energy-Efficient Multicasting in Ad Hoc Networks Stavros Technology Institute and Dept. of Computer Engineering and Informatics University of Patras, 26500 Rio, Greece Abstract. Energy is a scarce resource in ad hoc wireless networks and it is of paramount

  2. Energy production control of an experimental kite system in presence of wind gusts.

    E-print Network

    Paris-Sud XI, Université de

    Energy production control of an experimental kite system in presence of wind gusts. Rogelio Lozano of energy produced by the kite, and to be able to fly it safely in the presence of strong wind gusts. Our has three main objectives: - Stability against perturbations is a crucial point. Wind gusts can

  3. Determining Energy Expenditure From Treadmill Walking Using Hip-Worn Inertial Sensors: An Experimental Study

    Microsoft Academic Search

    Harshvardhan Vathsangam; Adar Emken; E. Todd Schroeder; Donna Spruijt-Metz; Gaurav S. Sukhatme

    2011-01-01

    We describe an experimental study to estimate energy expenditure during treadmill walking using a single hip-mounted inertial sensor (triaxial accelerometer and triaxial gyroscope). Typ- ical physical-activity characterization using commercial monitors use proprietary counts that do not have a physically interpretable meaning. This paper emphasizes the role of probabilistic tech- niques in conjunction with inertial data modeling to accurately predict energy

  4. 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. [Sandia National Labs., Albuquerque, NM (United States)

    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.

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

    SciTech Connect

    Jacobs, E.

    1983-01-01

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

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

    SciTech Connect

    Jacobs, E.W.

    1985-02-01

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

  7. Results from the STAR Beam Energy Scan Program

    E-print Network

    Lokesh Kumar; for the STAR Collaboration

    2011-01-22

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

  8. A gas-operated bearing damper for turbomachinery -- Theoretical predictions versus experimental measurements. Part 2: Experimental results and comparison with theory

    SciTech Connect

    Sundararajan, P.; Vance, J.M. [Texas A and M Univ., College Station, TX (United States). Dept. of Mechanical Engineering

    1995-10-01

    This is the second of two papers described results of a research project directed at developing a gas-operated vibration damper for high-temperature turbomachinery applications. This paper presents the experimental measurements made on a gas damper hardware and compares them with the theoretical predictions given in Part 1. It is found that the isentropic theoretical model predicts the damper characteristics quite well. A maximum damping of 2,310 N-s/m (13.2 lb-s/in.) was measured at a natural frequency of 118 Hz using the present design and the results suggest that significantly higher damping levels are possible with design modifications.

  9. (Experimental studies of elementary particle interactions at high energies)

    SciTech Connect

    Khuri, N.N.

    1990-01-01

    This report includes descriptions of the combined work of both Tasks B and B{sub 1} at Rockefeller University. Some highlights are worth stressing in this brief introduction. First, one should note the active involvement of two members of our group, Ren and Callaway, in understanding the problem of superconductivity, both high and low {Tc}. This reflects the broad reach of many, but perhaps not all, particle physicists. Second, spurred by the Rockefeller environment, some in our group are also looking at problems in biology. As for our main purpose, I would like to single out the results of Sanda and Morozumi on the {Delta}I = {1/2} rule, the work of Bitar, Ren and myself on a new approach to the path integral, S.Y. Pi's results on Chern-Simons non-relativistic quantum mechanics, and finally the work by Lee and collaborators on the origin of Fermion masses and mixing.

  10. Assessing Internet energy intensity: A review of methods and results

    SciTech Connect

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

    2014-02-15

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

  11. 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).

  12. 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.

  13. 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.

  14. An experimental investigation of aluminum honeycomb as an energy absorber 

    E-print Network

    Bland, William Joseph

    1964-01-01

    TESTING IV. DYNAMIC TESTING . V. RESULTS. VI. APPLICATION VII, CONCLUSIONS AND RECOMMENDATIONS 18 21 LITERATURE CITED 22 APPENDIX. 23 L IS T 0 F PLAT E 8 Plate Page 1. Aluminum Honeycomb Nomenclature 2. , Bare Compression Test before Crushing... 3. Bare Compression Test after Crushing 4. Square Head Producing Shear and Compression 5. Steel Shaft Used in Dynamic Testing for Head Attachments 12 6 . Dynamic Test with G ircula r Head 7. Static Specimen Illustrating Shear of Cell Walls 2 8...

  15. The influence of quark energy loss on extracting nuclear sea quark distribution from nuclear Drell-Yan experimental data

    E-print Network

    Duan Chun-Gui; Liu Na

    2008-09-28

    By means of two typical kinds of quark energy loss parametrization and the nuclear parton distributions determined only with lepton-nuclear deep inelastic scattering experimental data, a leading order analysis are performed on the proton-induced Drell-Yan differential cross section ratios of tungsten versus deuterium as a function of the quark momentum fraction in the beam proton and target nuclei. It is found that the theoretical results with quark energy loss are in good agreement with the experimental data. The quark energy loss effect produce approximately 3% to 11% suppression on the Drell-Yan differential cross section ratios $R_{W/D}$ in the range $0.05\\leq x_2\\leq0.3$. The application of nuclear Drell-Yan data with heavy targets is remarkably subject to difficulty in the constraints of the nuclear sea-quark distribution.

  16. New experimental study of low-energy (p,gamma) resonances in magnesium isotopes

    E-print Network

    B. Limata; F. Strieder; A. Formicola; G. Imbriani; M. Junker; H. W. Becker; D. Bemmerer; A. Best; R. Bonetti; C. Broggini; A. Caciolli; P. Corvisiero; H. Costantini; A. DiLeva; Z. Elekes; Zs. Fülöp; G. Gervino; A. Guglielmetti; C. Gustavino; Gy. Gyürky; A. Lemut; M. Marta; C. Mazzocchi; R. Menegazzo; P. Prati; V. Roca; C. Rolfs; C. Rossi Alvarez; C. Salvo; E. Somorjai; O. Straniero; F. Terrasi; H. -P. Trautvetter

    2010-06-28

    Proton captures on Mg isotopes play an important role in the Mg-Al cycle active in stellar H shell burning. In particular, the strengths of low-energy resonances with E < 200 keV in 25Mg(p,gamma)26Al determine the production of 26Al and a precise knowledge of these nuclear data is highly desirable. Absolute measurements at such low-energies are often very difficult and hampered by gamma-ray background as well as changing target stoichiometry during the measurements. The latter problem can be partly avoided using higher energy resonances of the same reaction as a normalization reference. Hence the parameters of suitable resonances have to be studied with adequate precision. In the present work we report on new measurements of the resonance strengths omega_gamma of the E = 214, 304, and 326 keV resonances in the reactions 24Mg(p,gamma)25Al, 25Mg(p,gamma)26Al, and 26Mg(p,gamma)27Al, respectively. These studies were performed at the LUNA facility in the Gran Sasso underground laboratory using multiple experimental techniques and provided results with a higher accuracy than previously achieved.

  17. A design and experimental verification methodology for an energy harvester skin structure

    NASA Astrophysics Data System (ADS)

    Lee, Soobum; Youn, Byeng D.

    2011-05-01

    This paper presents a design and experimental verification methodology for energy harvesting (EH) skin, which opens up a practical and compact piezoelectric energy harvesting concept. In the past, EH research has primarily focused on the design improvement of a cantilever-type EH device. However, such EH devices require additional space for proof mass and fixture and sometimes result in significant energy loss as the clamping condition becomes loose. Unlike the cantilever-type device, the proposed design is simply implemented by laminating a thin piezoelectric patch onto a vibrating structure. The design methodology proposed, which determines a highly efficient piezoelectric material distribution, is composed of two tasks: (i) topology optimization and (ii) shape optimization of the EH material. An outdoor condensing unit is chosen as a case study among many engineered systems with harmonic vibrating configuration. The proposed design methodology determined an optimal PZT material configuration on the outdoor unit skin structure. The designed EH skin was carefully prototyped to demonstrate that it can generate power up to 3.7 mW, which is sustainable for operating wireless sensor units for structural health monitoring and/or building automation.

  18. Save Energy Now Assessments Results 2008 Detailed Report

    SciTech Connect

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

    2010-09-01

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

  19. Save Energy Now Assessments Results 2008 Summary Report

    SciTech Connect

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

    2010-09-01

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

  20. Homestake result, sterile neutrinos and low energy solar neutrino experiments

    E-print Network

    P. C. de Holanda; A. Yu. Smirnov

    2004-03-29

    The Homestake result is about ~ 2 \\sigma lower than the Ar-production rate, Q_{Ar}, predicted by the LMA MSW solution of the solar neutrino problem. Also there is no apparent upturn of the energy spectrum (R \\equiv N_{obs}/N_{SSM}) at low energies in SNO and Super-Kamiokande. Both these facts can be explained if a light, \\Delta m^2_{01} ~ (0.2 - 2) \\cdot 10^{-5} eV^2, sterile neutrino exists which mixes very weakly with active neutrinos: \\sin^2 2\\alpha ~ (10^{-5} - 10^{-3}). We perform both the analytical and numerical study of the conversion effects in the system of two active neutrinos with the LMA parameters and one weakly mixed sterile neutrino. The presence of sterile neutrino leads to a dip in the survival probability in the intermediate energy range E = (0.5 - 5) MeV thus suppressing the Be, or/and pep, CNO as well as B electron neutrino fluxes. Apart from diminishing Q_{Ar} it leads to decrease of the Ge-production rate and may lead to decrease of the BOREXINO signal and CC/NC ratio at SNO. Future studies of the solar neutrinos by SNO, SK, BOREXINO and KamLAND as well as by the new low energy experiments will allow us to check this possibility. We present a general analysis of modifications of the LMA energy profile due to mixing with new neutrino states.

  1. Design Considerations and Experimental Results of a 60 W Compressed-Air-to-Electric-Power System

    Microsoft Academic Search

    D. Krahenbiihl; C. Zwyssig; H. Horler; J. W. Kolar

    2008-01-01

    In many process applications, where a pressure reduction is required the energy ends up being dissipated as heat. Examples are throttling valves of gas pipelines and automotive engines or turbo expanders as used in cryogenic plants. With a new pressure reduction system that produces electricity while expanding the gas, this lost energy can be recovered. To achieve a high power

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

    Microsoft Academic Search

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

    In many process applications, where a pressure reduction is required, the energy is being dissipated as heat. Examples are throttling valves of gas pipelines and automotive engines or turbo expanders as used in cryogenic plants. With a new pressure reduction system that produces electricity while expanding the gas, this lost energy can be recovered. To achieve a high power density

  3. Vortices in Bose-Einstein condensates: A review of the experimental results

    NASA Astrophysics Data System (ADS)

    Srinivasan, R.

    2006-01-01

    Rotating dilute Bose--Einstein condensates (BEC) of alkali atoms offer a testing ground for theories of vortices in weakly interacting superfluids. In a rotating superfluid, quantised vortices, with a vorticity h/m, form above a critical velocity. Such vortices have been generated in BEC of alkali atoms by different techniques such as (a) wave function engineering of a two-component BEC, (b) decay of solitons, (c) rotation of a thermal cloud before cooling it below the condensation temperature, (d) stirring with an `optical' spoon, (e) rotating a deformation in the anisotropic trap in which the condensate is trapped and (f) by creating Berry phase by adiabatically reversing the axial magnetic field. Since the core of a vortex is a fraction of a micrometer in diameter, it cannot be directly imaged optically. The condensate with vortices is allowed to ballistically expand till the size increases by one order before the vortices are imaged. Surface wave spectroscopy and the change in aspect ratio of a rotating cloud are the other techniques used. Studies have been made on the creation and dynamics of single vortex and on systems with more than a hundred vortices. Results have been obtained on vortex nucleation, stability of vortex structures, nature of the vortex lattice and defects in such a lattice. Important results are: (a) evidence exists that vortex nucleation takes place by a surface mode instability; but this is not the only mechanism; (b) the vortex lattice is perfectly triangular right up to the edge; (c) in the initial stages of rotation of the cloud a tangled web of vortices is seen; it takes a few hundred milliseconds before the vortices arrange themselves in a lattice; this time appears to be independent of temperature; (d) the decay of vortices appears to arise from the transfer of energy to the rotating thermal component and is dependent on temperature; (e) defects in the lattices such as dislocations and grain boundaries are seen; (f) transverse oscillations (Tkachenko modes) of the vortex lattice have been observed; and (g) giant vortices have been produced. These will be discussed.

  4. Periodic Orbit theory for Resonant Tunneling Diodes : comparison with quantum and experimental results

    E-print Network

    D. S. Saraga; T. S. Monteiro; D. C. Rouben

    1998-06-04

    We investigate whether the quantal and experimental amplitudes of current oscillations of Resonant Tunneling Diodes in tilted fields are obtainable from Periodic Orbit (PO) theories by considering recently proposed PO approaches. We show, for the first time, that accurate amplitudes and frequency shifts for the current oscillations (typically to within a few %) can be obtained from a simple analytical formula both in the stable (torus-quantization) limit and the unstable regimes of the experiments which are dominated by isolated PO's. But we find that the PO approach does not describe quantitatively the dynamically interesting intermediate experimental regimes which appear to be dominated by contributions from complex orbits and multiple non-isolated PO's. We conclude that these regimes will not easily be described by the usual PO approach, even with simple normal forms.

  5. Experimental Energy Balance During the First Cycles of Cyclically Loaded Specimens Under the Conventional Yield Stress

    Microsoft Academic Search

    N. Connesson; F. Maquin; F. Pierron

    2011-01-01

    This paper, as an extension of Maquin and Pierron (Mech Mater 41(8):928–942, 2009), presents an experimental procedure developed to macroscopically estimate the energy balance during the very first cycles\\u000a of a uniaxially loaded metallic specimen at low stress levels. This energy balance is performed by simultaneously measuring\\u000a the plastic input energy using a load cell and a strain gauge, and

  6. Experimental energy loss of slow H{sup +} and Hâ{sup +} in channeling conditions

    Microsoft Academic Search

    J. E. Valdes; C. Parra; J. Diaz-Valdes; C. D. Denton; C. Agurto; F. Ortega; N. R. Arista; P. Vargas

    2003-01-01

    The interactions of hydrogen molecular ions (Hâ{sup +}) and protons in the low energy range (E<7.5 keV\\/u) with very thin foils of monocrystalline gold are experimentally studied. Measurements of energy loss distributions of molecular fragments, recombined molecules, and protons channeled in the <100> direction of a monocrystalline gold thin film have been performed. From the energy loss data we determine

  7. 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.

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

    Microsoft Academic Search

    E. Azad

    2009-01-01

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

  9. Wireless power transfer in the presence of metallic plates: Experimental results

    NASA Astrophysics Data System (ADS)

    Yu, Xiaofang; Skauli, Torbjo?rn; Skauli, Bjo?rn; Sandhu, Sunil; Catrysse, Peter B.; Fan, Shanhui

    2013-06-01

    We demonstrate efficient wireless power transfer between two high Q resonators, especially in a complex electromagnetic environment. In the close proximity of metallic plates, the transfer efficiency stays roughly the same as the free space efficiency with proper designs. The experimental data fits well with a coupled theory model. Resonance frequency matching, alignment of the magnetic field, and impedance matching are shown to be the most important factors for efficient wireless power transfer.

  10. Boundary conditions for creeping flow along periodic or random rough surfaces : experimental and theoretical results

    NASA Astrophysics Data System (ADS)

    Lecoq, Nicolas

    2012-12-01

    Hydrodynamic interactions between particles and walls are relevant for the open problem of specifying boundary conditions for suspension flows. The Reynolds number around a small particle close to a wall is usually low and creeping flow equations apply. From the solution of these equations, the drag coefficient on a sphere becomes infinite when the gap between the sphere and a smooth wall vanishes, so that contact may not occur. Physically, the drag is finite because of various reasons, one of them being the particle and wall roughness. Then, for vanishing gap, even though some layers of fluid molecules may be left between the particle and wall roughness peaks, it may conventionally be said that contact occurs. In this paper, we are considering the example of a smooth sphere moving towards a rough wall. The roughness considered here consist of random rough planes or parallel periodic wedges, the characteristic length of which is small compared with the sphere radius. This problem is considered both experimentally and theoretically. The motion of a millimetre size bead settling towards a corrugated horizontal wall in a viscous oil is measured with laser interferometry giving an accuracy on the displacement of 0.2?m. Several random rough planes and wedge shaped walls were used, with various wavelengths and wedge angles. From the results, it is observed that the velocity of the sphere is, except for small gaps, similar to that towards a smooth plane that is shifted down from the top of corrugations. For the periodic wedges, the creeping flow is calculated as a series in the slope of the roughness grooves. The convergence of the series for the shift distance in term of the slope is accelerated by use of Euler transformation and of the existence of a limit for large slope. The cases of a flow along and across the grooves are considered separately. The shift is larger in the former case. Slightly flattened tops of the wedges used in experiments are also considered in the calculations. The effective theoretical shift for a sphere approaching a wall is obtained from Lorentz reciprocal theorem with an expansion for small roughness compared with the gap between the sphere and the wall. The effective shift is found to be the average of the shifts for shear flows in the two perpendicular directions. A good agreement is found between theory and experiment. The theoretical description of the flow close to the random rough wall represents a difficult, nearly insurmountable problem except in lattice Boltzmann simulations. Statistical analysis is presented in this paper to deduce the effective shift for sand-blasted rough surfaces. To overcome the difficulties of modelling, a regular perturbation expansion is developed, and from Lorentz reciprocal theorem, the first order correction to the drag force due to random roughness is evaluated.

  11. Experimental observation of the inverse energy and forward enstrophy cascades in 2D turbulence.

    NASA Astrophysics Data System (ADS)

    Rutgers, Maarten A.

    1998-11-01

    Soap films have proven to be a unique system for studying quasi 2D flows in the laboratory. Recent advances in experimental techniques have made it possible to closely study 2D turbulence at a reasonably high Reynolds number^1. In earlier experiments turbulence was generated by placing a grid (comb) across a channel containing a flowing soap film. This turbulence decayed continually after passing the comb. Measurements of the decay^2 are in agreement with calculations^3 and show only evidence of an enstrophy cascade. In our current experiments we continually force the turbulence by injecting vorticity into the turbulence at a small, well defined, wave number. We accomplish this by placing grids (arrays of thin cylinders) along the channel walls. A steady state forced 2D turbulence is the result. The turbulent energy spectra clearly show k-5/3 scaling at large wave numbers. At shorter wave numbers E(k) ~ k-3, associated with a forward enstrophy cascade. These data are strong experimental evidence corroborating the current theories on 2D turbulence. Downstream from the forcing region, the k-5/3 portion of the spectrum continuously diminishes until only the k-3 scaling remains. This is in agreement with the current understanding of decaying 2D turbulence. ^1W.I. Goldburg et al. Physica A 239 (1997) 340. ^2 B.K. Martin et al, Phys. Rev. Lett. 80 (1998) 3964. ^3 J. R. Chasnov, Phys. Fluids 9 (1997) 171.

  12. Experimental investigation of ?130 keV kinetic energy antiprotons annihilation on nuclei

    NASA Astrophysics Data System (ADS)

    Aghai-Khozani, H.; Barna, D.; Corradini, M.; Hayano, R.; Hori, M.; Kobayashi, T.; Leali, M.; Lodi-Rizzini, E.; Mascagna, V.; Prest, M.; Soter, A.; Todoroki, K.; Vallazza, E.; Venturelli, L.; Zurlo, N.

    2014-04-01

    The study of the antiproton ( bar {p}) annihilation cross section on nuclei at low energies (eV-MeV region) has implications for fundamental cosmology as well as for nuclear physics. Concerning the former, different models try to explain the matter/antimatter asymmetry in the universe assuming the existence of the so-called "islands" where antinucleon-nucleon annihilations occur in the border region (Cohen et al. Astrophys. J. 495, 539-549, 1998), while, from the nuclear physics point of view, the annihilation process is a valuable tool to evaluate the neutron/proton ratio in order to probe the external region of the nucleus (Gupta et al. Nucl. Phys. B 70(3), 414-424, 1974). The existing data of antinucleon-nucleon (or -nucleus) annihilation cross-sections are mainly confined to energies above ?1 MeV, while the cross section measured at LEAR in the 80's-90's (mostly with light targets Agnello et al. Phys. Lett. B 256, 349-353, 1991; Bertin et al. Phys. Lett. B 369, 77-85, 1996; Bertin et al. Phys. Lett. B 414, 220-228, 1997; Zenoni et al. Phys. Lett. B 461, 405-412, 1999; Bianconi et al. Phys. Lett. B 481, 194-198, 2000; Bianconi et al. Phys. Lett. B 492, 254-258, 2000) showed an unexpected behaviour for energies below 1 MeV (Bianconi et al. Phys. Lett. B 483, 353-359, 2000; Bianconi et al. Phys. Rev. C 62, 014611-7, 2000; Batty et al. Nucl. Phys. A 689, 721-740, 2001). The results showed a saturation with the atomic mass number against the A 2/3 trend which is observed for higher energies (being A the target mass number). The ASACUSA collaboration at CERN recently measured antiproton annihilation cross section on different kinds of nuclei with a bar {p} kinetic energy of 5.3 MeV (Bianconi et al. Phys. Lett. B 704, 461-466, 2011; Corradini et al. Nucl. Instr. Methods A 711, 12-20, 2013). Such results proved compatibility with the black-disk model with the Coulomb correction. But till now experimental difficulties prevented the investigation at energies below ?1 MeV. In 2012, the 100 keV region has been investigated for the first time (Aghai-Khozani et al. Eur. Phys. J. Plus 127, 125-128, 2012). We present here the first preliminary results of this experiment.

  13. A theoretical model of the application of RF energy to the airway wall and its experimental validation

    PubMed Central

    2010-01-01

    Background Bronchial thermoplasty is a novel technique designed to reduce an airway's ability to contract by reducing the amount of airway smooth muscle through controlled heating of the airway wall. This method has been examined in animal models and as a treatment for asthma in human subjects. At the present time, there has been little research published about how radiofrequency (RF) energy and heat is transferred to the airways of the lung during bronchial thermoplasty procedures. In this manuscript we describe a computational, theoretical model of the delivery of RF energy to the airway wall. Methods An electro-thermal finite-element-analysis model was designed to simulate the delivery of temperature controlled RF energy to airway walls of the in vivo lung. The model includes predictions of heat generation due to RF joule heating and transfer of heat within an airway wall due to thermal conduction. To implement the model, we use known physical characteristics and dimensions of the airway and lung tissues. The model predictions were tested with measurements of temperature, impedance, energy, and power in an experimental canine model. Results Model predictions of electrode temperature, voltage, and current, along with tissue impedance and delivered energy were compared to experiment measurements and were within ± 5% of experimental averages taken over 157 sample activations. The experimental results show remarkable agreement with the model predictions, and thus validate the use of this model to predict the heat generation and transfer within the airway wall following bronchial thermoplasty. Conclusions The model also demonstrated the importance of evaporation as a loss term that affected both electrical measurements and heat distribution. The model predictions showed excellent agreement with the empirical results, and thus support using the model to develop the next generation of devices for bronchial thermoplasty. Our results suggest that comparing model results to RF generator electrical measurements may be a useful tool in the early evaluation of a model. PMID:21110893

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

    NASA Astrophysics Data System (ADS)

    Israbian, C.

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

  15. 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.

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

    NASA Technical Reports Server (NTRS)

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

    1987-01-01

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

  17. Homogenizing a Nickel-Based Superalloy: Thermodynamic and Kinetic Simulation and Experimental Results

    SciTech Connect

    Paul D. Jablonski; Christopher J. Cowen

    2009-03-01

    If the chemical inhomogeneity profile is known a priori, kinetic modeling software such as diffusion-controlled transformations (DICTRA) can be used to model the homogenization kinetics of an alloy. In this study, the Scheil module within the Thermo-Calc software was used to predict the as-cast segregation present within the Ni-based superalloy Nimonic 105. The segregation profiles were read into DICTRA to refine the homogenization heat treatment of this alloy. The thermodynamic and kinetic modeling of the computationally predicted heat treatment and microstructure, and subsequent experimental verification on a real casting of Nimonic 105, are presented.

  18. Charging characteristics of materials: Comparison of experimental results with simple analytical models

    NASA Technical Reports Server (NTRS)

    Purvis, C. K.; Stevens, N. J.; Oglebay, J. C.

    1977-01-01

    An understanding of the behavior of materials, of dielectrics in particular, under charged particle bombardment is essential to the prediction and prevention of the adverse effects of spacecraft charging. A one-dimensional model for charging of samples in a test facility was used in conjunction with experimental data taken to develop "material charging characteristics" for silvered Teflon. These characteristics were then used in a one-dimensional model for charging in space to examine expected response. Relative charging rates as well as relative charging levels for silvered Teflon and metal are discussed.

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

    SciTech Connect

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

    1996-08-13

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

  20. Studies of MCP Sensitivity to 250 eV to 25 keV x-rays: Comparisons of Monte Carlo Simulations and Experimental Results

    NASA Astrophysics Data System (ADS)

    Wu, Ming; Kruschwitz, Craig; Moy, Ken; Rochau, Greg; Sandia National Laboratories Team; National Security Technologies, Inc. Team

    2014-10-01

    We present results of Monte Carlo simulations of microchannel plate (MCP) response to x-rays in the 250 eV to 25 keV energy range as a function of x-ray energy, impact angle, and x-ray flux. X-ray penetration through multiple MCP pore walls is increasingly important above 5 keV and the effect of this penetration on MCP performance is studied. In agreement with past measurements, it is found that the angular dependence of MCP sensitivity with angle changes from a cotangent dependence to angular independence as x-ray energy increases. It is also found that the MCP gain sensitivity with voltage decreases for higher x-ray energies. Finally, it is found that for x-rays incident at zero degrees relative to the MCP surface normal, spatial resolution shows little dependence on x-ray energy, but that spatial resolution degrades for higher x-ray energies as the angle of incidence relative to the surface normal increases. Dynamic range of MCP in this energy range is also examined. Simulation results are compared to recent experimental measurements for 6-25 keV x-rays. The experiments were performed on the X15 beamline at the National Synchrotron Light Source (NSLS) at Brookhaven National Laboratory. Agreement between simulations and experiments is generally very good.