Science.gov

Sample records for baseline experiment simulator

  1. GLoBES: General Long Baseline Experiment Simulator

    NASA Astrophysics Data System (ADS)

    Huber, Patrick; Kopp, Joachim; Lindner, Manfred; Rolinec, Mark; Winter, Walter

    2007-09-01

    GLoBES (General Long Baseline Experiment Simulator) is a flexible software package to simulate neutrino oscillation long baseline and reactor experiments. On the one hand, it contains a comprehensive abstract experiment definition language (AEDL), which allows to describe most classes of long baseline experiments at an abstract level. On the other hand, it provides a C-library to process the experiment information in order to obtain oscillation probabilities, rate vectors, and Δχ-values. Currently, GLoBES is available for GNU/Linux. Since the source code is included, the port to other operating systems is in principle possible. GLoBES is an open source code that has previously been described in Computer Physics Communications 167 (2005) 195 and in Ref. [7]). The source code and a comprehensive User Manual for GLoBES v3.0.8 is now available from the CPC Program Library as described in the Program Summary below. The home of GLobES is http://www.mpi-hd.mpg.de/~globes/. Program summaryProgram title: GLoBES version 3.0.8 Catalogue identifier: ADZI_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/ADZI_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 145 295 No. of bytes in distributed program, including test data, etc.: 1 811 892 Distribution format: tar.gz Programming language: C Computer: GLoBES builds and installs on 32bit and 64bit Linux systems Operating system: 32bit or 64bit Linux RAM: Typically a few MBs Classification: 11.1, 11.7, 11.10 External routines: GSL—The GNU Scientific Library, www.gnu.org/software/gsl/ Nature of problem: Neutrino oscillations are now established as the leading flavor transition mechanism for neutrinos. In a long history of many experiments, see, e.g., [1], two oscillation frequencies have been identified: The fast atmospheric

  2. Long Baseline Neutrino Experiment simulation studies on Offset of Detector and Proton Beam

    NASA Astrophysics Data System (ADS)

    Bashyal, Amit; Yu, Jaehoon; Park, Seongtae; Watson, Blake

    2014-03-01

    The Long Baseline Neutrino Experiment(LBNE), hosted by Fermilab is a world class physics program aiming to probe our understanding on neutrino physics and look for physics beyond Standard Model. While LBNE is still under development, the LBNE beam simulation group performs the simulation using the G4LBNE simulation software and packaged geometry. The simulation studies are done by shifting and offsetting several parameters (which represent the physical components of the real experiment). The results obtained were analyzed graphically and statistically. In this talk, I will explain the effect of beam offset and detector shifting on parameters like pion production in the decay pipe, intensity of neutrino flux, variation on the number of neutrinos in specific energy ranges. Simulation experiment results will help to simplify the complex nature of neutrinos itself to a small extent and the collective work from the beam simulation group can provide a raw guideline for the experiment itself in the long run.

  3. Simulations of the Long Baseline Neutrino Experiment for the Sieroszowice Underground Laboratory (SUNLAB)

    NASA Astrophysics Data System (ADS)

    Harańczyk, Małgorzata

    2016-02-01

    The Sieroszowice Underground Laboratory in Poland, SUNLAB, had been studied in the years 2008-2011 within the framework of the FP7 LAGUNA design study as an option for the realization of a next generation large volume neutrino observatory in Europe. However, in order to fully understand its physics capabilities, the feasibility studies of the SUNLAB laboratory have continued after 2011, including sensitivity calculations focused on the delta CP measurement for a large LArTPC detector at a distance of 950 km from CERN in a long baseline neutrino experiment. For this purpose the neutrino beam based on the SPS proton accelerator at CERN was simulated and the LAr data used to simulate the detector response.

  4. Long Baseline Neutrino Experiments

    NASA Astrophysics Data System (ADS)

    Mezzetto, Mauro

    2016-05-01

    Following the discovery of neutrino oscillations by the Super-Kamiokande collaboration, recently awarded with the Nobel Prize, two generations of long baseline experiments had been setup to further study neutrino oscillations. The first generation experiments, K2K in Japan, Minos in the States and Opera in Europe, focused in confirming the Super-Kamiokande result, improving the precision with which oscillation parameters had been measured and demonstrating the ντ appearance process. Second generation experiments, T2K in Japan and very recently NOνA in the States, went further, being optimized to look for genuine three neutrino phenomena like non-zero values of θ13 and first glimpses to leptonic CP violation (LCPV) and neutrino mass ordering (NMO). The discovery of leptonic CP violation will require third generation setups, at the moment two strong proposals are ongoing, Dune in the States and Hyper-Kamiokande in Japan. This review will focus a little more in these future initiatives.

  5. SIMULATION OF A WIDE-BAND LOW-ENERGY NEUTRINO BEAM FOR VERY LONG BASELINE NEUTRINO OSCILLATION EXPERIMENTS.

    SciTech Connect

    BISHAI, M.; HEIM, J.; LEWIS, C.; MARINO, A.D.; VIREN, B.; YUMICEVA, F.

    2006-08-01

    We present simulations of a wide-band low-energy neutrino beam for a future very long baseline neutrino oscillation (VLBNO) program using the proton beam from the Main Injector (MI) proton accelerator at Fermi National Accelerator Laboratory (Fermilab). The target and horn designs previously developed for Brookhaven Laboratory's Alternating Gradient Synchrotron (AGS) VLBNO program are used without modifications. The neutrino flux distributions for various MI proton beam energies and new high-intensity neutrino beam-line designs possible at Fermilab are presented. The beam-line siting and design parameters are chosen to match the requirements of an on-axis beam from Fermilab to one of the two possible sites for the future Deep Underground Science and Engineering Laboratory (DUSEL). A preliminary estimate of the observable event rates and spectra at a detector located in DUSEL for different beam configurations has been performed. Our preliminary conclusions are that a 40-60 GeV 0.5 to 1 MW beam from the Fermilab Main Injector to a DUSEL site has the potential to reach the desired intensity for the next generation of neutrino oscillation experiments. Recent studies indicate that the Fermilab MI can reach a beam power of 0.5 MW at 60 GeV with incremental upgrades to the existing accelerator complex.

  6. Dissipative effect in long baseline neutrino experiments

    NASA Astrophysics Data System (ADS)

    Oliveira, Roberto L. N.

    2016-07-01

    The propagation of neutrinos in long baselines experiments may be influenced by dissipation effects. Using the Lindblad master equation we evolve neutrinos taking into account these dissipative effects. The MSW and the dissipative effects may change the behavior of the probabilities. In this work, we show and explain how the behavior of the probabilities can change due to the decoherence and relaxation effects acting individually with the MSW effect. A new exotic peak appears in this case and we show the difference between the decoherence and relaxation effects in the appearance of this peak. We also adapt the usual approximate expression for survival and appearance probabilities with all possible decoherence effects. We suppose the baseline of DUNE and show how each of the decoherence parameters changes the probabilities analyzing the possible modification using a numeric and an analytic approach.

  7. CASA Uno GPS orbit and baseline experiments

    NASA Technical Reports Server (NTRS)

    Schutz, B. E.; Ho, C. S.; Abusali, P. A. M.; Tapley, B. D.

    1990-01-01

    CASA Uno data from sites distributed in longitude from Australia to Europe have been used to determine orbits of the GPS satellites. The characteristics of the orbits determined from double difference phase have been evaluated through comparisons of two-week solutions with one-week solutions and by comparisons of predicted and estimated orbits. Evidence of unmodeled effects is demonstrated, particularly associated with the orbit planes that experience solar eclipse. The orbit accuracy has been assessed through the repeatability of unconstrained estimated baseline vectors ranging from 245 km to 5400 km. Both the baseline repeatability and the comparison with independent space geodetic methods give results at the level of 1-2 parts in 100,000,000. In addition, the Mojave/Owens Valley (245 km) and Kokee Park/Ft. Davis (5409 km) estimates agree with VLBI and SLR to better than 1 part in 100,000,000.

  8. Long-baseline neutrino oscillation experiments

    SciTech Connect

    Crane, D.; Goodman, M.

    1994-12-31

    There is no unambiguous definition for long baseline neutrino oscillation experiments. The term is generally used for accelerator neutrino oscillation experiments which are sensitive to {Delta}m{sup 2} < 1.0 eV{sup 2}, and for which the detector is not on the accelerator site. The Snowmass N2L working group met to discuss the issues facing such experiments. The Fermilab Program Advisory Committee adopted several recommendations concerning the Fermilab neutrino program at their Aspen meeting immediately prior to the Snowmass Workshop. This heightened the attention for the proposals to use Fermilab for a long-baseline neutrino experiment at the workshop. The plan for a neutrino oscillation program at Brookhaven was also thoroughly discussed. Opportunities at CERN were considered, particularly the use of detectors at the Gran Sasso laboratory. The idea to build a neutrino beam from KEK towards Superkamiokande was not discussed at the Snowmass meeting, but there has been considerable development of this idea since then. Brookhaven and KEK would use low energy neutrino beams, while FNAL and CERN would plan have medium energy beams. This report will summarize a few topics common to LBL proposals and attempt to give a snapshot of where things stand in this fast developing field.

  9. Simulated Experiments

    ERIC Educational Resources Information Center

    Snadden, R. B.; Runquist, O.

    1975-01-01

    Presents an experiment in which a programmable calculator is employed as a data generating system for simulated laboratory experiments. The example used as an illustration is a simulated conductimetric titration of an aqueous solution of HC1 with an aqueous solution of NaOH. (Author/EB)

  10. Design of experiment for earth rotation and baseline parameter determination from very long baseline interferometry

    NASA Technical Reports Server (NTRS)

    Dermanis, A.

    1977-01-01

    The possibility of recovering earth rotation and network geometry (baseline) parameters are emphasized. The numerical simulated experiments performed are set up in an environment where station coordinates vary with respect to inertial space according to a simulated earth rotation model similar to the actual but unknown rotation of the earth. The basic technique of VLBI and its mathematical model are presented. The parametrization of earth rotation chosen is described and the resulting model is linearized. A simple analysis of the geometry of the observations leads to some useful hints on achieving maximum sensitivity of the observations with respect to the parameters considered. The basic philosophy for the simulation of data and their analysis through standard least squares adjustment techniques is presented. A number of characteristic network designs based on present and candidate station locations are chosen. The results of the simulations for each design are presented together with a summary of the conclusions.

  11. Shuttle mission simulator baseline definition report, volume 1

    NASA Technical Reports Server (NTRS)

    Burke, J. F.; Small, D. E.

    1973-01-01

    A baseline definition of the space shuttle mission simulator is presented. The subjects discussed are: (1) physical arrangement of the complete simulator system in the appropriate facility, with a definition of the required facility modifications, (2) functional descriptions of all hardware units, including the operational features, data demands, and facility interfaces, (3) hardware features necessary to integrate the items into a baseline simulator system to include the rationale for selecting the chosen implementation, and (4) operating, maintenance, and configuration updating characteristics of the simulator hardware.

  12. Neutrino Oscillation Parameter Sensitivity in Future Long-Baseline Experiments

    SciTech Connect

    Bass, Matthew

    2014-01-01

    The study of neutrino interactions and propagation has produced evidence for physics beyond the standard model and promises to continue to shed light on rare phenomena. Since the discovery of neutrino oscillations in the late 1990s there have been rapid advances in establishing the three flavor paradigm of neutrino oscillations. The 2012 discovery of a large value for the last unmeasured missing angle has opened the way for future experiments to search for charge-parity symmetry violation in the lepton sector. This thesis presents an analysis of the future sensitivity to neutrino oscillations in the three flavor paradigm for the T2K, NO A, LBNE, and T2HK experiments. The theory of the three flavor paradigm is explained and the methods to use these theoretical predictions to design long baseline neutrino experiments are described. The sensitivity to the oscillation parameters for each experiment is presented with a particular focus on the search for CP violation and the measurement of the neutrino mass hierarchy. The variations of these sensitivities with statistical considerations and experimental design optimizations taken into account are explored. The effects of systematic uncertainties in the neutrino flux, interaction, and detection predictions are also considered by incorporating more advanced simulations inputs from the LBNE experiment.

  13. Shuttle mission simulator baseline definition report, volume 2

    NASA Technical Reports Server (NTRS)

    Dahlberg, A. W.; Small, D. E.

    1973-01-01

    The baseline definition report for the space shuttle mission simulator is presented. The subjects discussed are: (1) the general configurations, (2) motion base crew station, (3) instructor operator station complex, (4) display devices, (5) electromagnetic compatibility, (6) external interface equipment, (7) data conversion equipment, (8) fixed base crew station equipment, and (9) computer complex. Block diagrams of the supporting subsystems are provided.

  14. Synthesizing SMOS Zero-Baselines with Aquarius Brightness Temperature Simulator

    NASA Technical Reports Server (NTRS)

    Colliander, A.; Dinnat, E.; Le Vine, D.; Kainulainen, J.

    2012-01-01

    SMOS [1] and Aquarius [2] are ESA and NASA missions, respectively, to make L-band measurements from the Low Earth Orbit. SMOS makes passive measurements whereas Aquarius measures both passive and active. SMOS was launched in November 2009 and Aquarius in June 2011.The scientific objectives of the missions are overlapping: both missions aim at mapping the global Sea Surface Salinity (SSS). Additionally, SMOS mission produces soil moisture product (however, Aquarius data will eventually be used for retrieving soil moisture too). The consistency of the brightness temperature observations made by the two instruments is essential for long-term studies of SSS and soil moisture. For resolving the consistency, the calibration of the instruments is the key. The basis of the SMOS brightness temperature level is the measurements performed with the so-called zero-baselines [3]; SMOS employs an interferometric measurement technique which forms a brightness temperature image from several baselines constructed by combination of multiple receivers in an array; zero-length baseline defines the overall brightness temperature level. The basis of the Aquarius brightness temperature level is resolved from the brightness temperature simulator combined with ancillary data such as antenna patterns and environmental models [4]. Consistency between the SMOS zero-baseline measurements and the simulator output would provide a robust basis for establishing the overall comparability of the missions.

  15. Constraining the nonstandard interaction parameters in long baseline neutrino experiments

    NASA Astrophysics Data System (ADS)

    Huitu, Katri; Kärkkäinen, Timo J.; Maalampi, Jukka; Vihonen, Sampsa

    2016-03-01

    In this article we investigate the prospects for probing the strength of the possible nonstandard neutrino interactions (NSI) in long baseline neutrino oscillation experiments. We find that these experiments are sensitive to NSI couplings down to the level of 0.01-0.1 depending on the oscillation channel and the baseline length, as well as on the detector's fiducial mass. We also investigate the interference of the leptonic C P angle δC P with the constraining of the NSI couplings. It is found that the interference is strong in the case of the νe↔νμ and νe↔ντ transitions but not significant in other transitions. In our numerical analysis we apply the GLoBES software and use the LBNO setup as our benchmark.

  16. Linking solar and long baseline terrestrial neutrino experiments.

    PubMed

    Akhmedov, E K; Branco, G C; Rebelo, M N

    2000-04-17

    We show that, in the framework of three light neutrino species with hierarchical masses and assuming no fine tuning between the entries of the neutrino mass matrix, one can use the solar neutrino data to obtain information on the element U(e3) of the lepton mixing matrix. Conversely, a measurement of U(e3) in atmospheric or long baseline accelerator or reactor neutrino experiments would help discriminate between possible oscillation solutions of the solar neutrino problem. PMID:11019139

  17. Updated results of the OPERA long baseline neutrino experiment

    NASA Astrophysics Data System (ADS)

    Chukanov, Artem; Opera Collaboration

    2012-07-01

    The OPERA neutrino detector built in the underground Gran Sasso Laboratory is designed to detect νμ → ντ oscillations in direct appearance mode. The hybrid apparatus consists of an emulsion/lead target complemented by electronic detectors. It is placed in the long-baseline CERN to Gran Sasso neutrino beam (CNGS) 730 km away from the source. The experimental setup and ancillary facilities used to extract data recorded in the emulsion will be described, with the special procedures used to locate the interactions vertices and detect short decay topologies. OPERA is taking data since 2008. A first ντ interaction candidate was already published in 2010. An improved analysis scheme associated with a more detailed simulation has been developed and new results with increased statistics will be presented.

  18. Energy reconstruction in the long-baseline neutrino experiment.

    PubMed

    Mosel, U; Lalakulich, O; Gallmeister, K

    2014-04-18

    The Long-Baseline Neutrino Experiment aims at measuring fundamental physical parameters to high precision and exploring physics beyond the standard model. Nuclear targets introduce complications towards that aim. We investigate the uncertainties in the energy reconstruction, based on quasielastic scattering relations, due to nuclear effects. The reconstructed event distributions as a function of energy tend to be smeared out and shifted by several 100 MeV in their oscillatory structure if standard event selection is used. We show that a more restrictive experimental event selection offers the possibility to reach the accuracy needed for a determination of the mass ordering and the CP-violating phase. Quasielastic-based energy reconstruction could thus be a viable alternative to the calorimetric reconstruction also at higher energies. PMID:24785030

  19. Observing System Simulation Experiments

    NASA Technical Reports Server (NTRS)

    Prive, Nikki

    2015-01-01

    This presentation gives an overview of Observing System Simulation Experiments (OSSEs). The components of an OSSE are described, along with discussion of the process for validating, calibrating, and performing experiments. a.

  20. Degeneracies in long-baseline neutrino experiments from nonstandard interactions

    NASA Astrophysics Data System (ADS)

    Liao, Jiajun; Marfatia, Danny; Whisnant, Kerry

    2016-05-01

    We study parameter degeneracies that can occur in long-baseline neutrino appearance experiments due to nonstandard interactions (NSI) in neutrino propagation. For a single off-diagonal NSI parameter, and neutrino and antineutrino measurements at a single L /E , there exists a continuous four-fold degeneracy (related to the mass hierarchy and θ23 octant) that renders the mass hierarchy, octant, and C P phase unknowable. Even with a combination of NO ν A and T2K data, which in principle can resolve the degeneracy, both NSI and the C P phase remain unconstrained because of experimental uncertainties. A wide-band beam experiment like DUNE will resolve this degeneracy if the nonzero off-diagonal NSI parameter is ɛe μ. If ɛe τ is nonzero, or the diagonal NSI parameter ɛe e is O (1 ), a wrong determination of the mass hierarchy and of C P violation can occur at DUNE. The octant degeneracy can be further complicated by ɛe τ, but is not affected by ɛe e.

  1. Scientific Opportunities with the Long-Baseline Neutrino Experiment

    SciTech Connect

    Adams, C.; et al.,

    2013-07-28

    In this document, we describe the wealth of science opportunities and capabilities of LBNE, the Long-Baseline Neutrino Experiment. LBNE has been developed to provide a unique and compelling program for the exploration of key questions at the forefront of particle physics. Chief among the discovery opportunities are observation of CP symmetry violation in neutrino mixing, resolution of the neutrino mass hierarchy, determination of maximal or near-maximal mixing in neutrinos, searches for nucleon decay signatures, and detailed studies of neutrino bursts from galactic supernovae. To fulfill these and other goals as a world-class facility, LBNE is conceived around four central components: (1) a new, intense wide-band neutrino source at Fermilab, (2) a fine-grained `near' neutrino detector just downstream of the source, (3) the Sanford Underground Research Facility (SURF) in Lead, South Dakota at an optimal distance (~1300 km) from the neutrino source, and (4) a massive liquid argon time-projection chamber (LArTPC) deployed there as a 'far' detector. The facilities envisioned are expected to enable many other science opportunities due to the high event rates and excellent detector resolution from beam neutrinos in the near detector and atmospheric neutrinos in the far detector. This is a mature, well developed, world class experiment whose relevance, importance, and probability of unearthing critical and exciting physics has increased with time.

  2. Long baseline neutrino oscillation experiment at the AGS

    NASA Astrophysics Data System (ADS)

    Beavis, D.; Carroll, A.; Chiang, I.

    1995-04-01

    The authors present a design for a multidetector long baseline neutrino oscillation experiment at the BNL AGS. It has been approved by the BNL-HENP-PAC as AGS Experiment 889. The experiment will search for oscillations in the nu(sub mu) disappearance channel and the nu(sub mu) reversible reaction nu(sub e) appearance channel by means of four identical neutrino detectors located 1, 3, 24, and 68 km from the AGS neutrino source. Observed depletion of the nu(sub mu) flux (via quasi-elastic muon neutrino events, nu(sub mu)n yields mu(-)p) in the far detectors not attended by an observed proportional increase of the nu(sub e) flux (via quasi-elastic electron neutrino events, nu(sub e)n yields e(-)p) in those detectors will be prima facie evidence for the oscillation channel nu(sub mu) reversible reaction nu(sub tau). The experiment is directed toward exploration of the region of the neutrino oscillation parameters Delta m(exp 2) and sin(exp 2) 2 theta, suggested by the Kamiokande and IMB deep underground detectors but it will also explore a region more than two orders of magnitude larger than that of previous accelerator experiments. The experiment will run in a mode new to BNL. It will receive the fast extracted proton beam on the neutrino target approximately 20 hours per day when the AGS is not filling RHIC. A key aspect of the experimental design involves placing the detectors 1.5 degrees off the center line of the neutrino beam, which has the important advantage that the central value of the neutrino energy (approximately 1 GeV) and the beam spectral shape are, to a good approximation, the same in all four detectors. The proposed detectors are massive, imaging, water Cherenkov detectors similar in large part to the Kamiokande and IMB detectors. The design has profited from their decade-long experience, and from the detector designs of the forthcoming SNO and SuperKamiokande detectors.

  3. Human Simulated Diving Experiments.

    ERIC Educational Resources Information Center

    Bruce, David S.; Speck, Dexter F.

    1979-01-01

    This report details several simulated divinq experiments on the human. These are suitable for undergraduate or graduate laboratories in human or environmental physiology. The experiment demonstrates that a diving reflex is precipitated by both facial cooling and apnea. (Author/RE)

  4. THE FIRST VERY LONG BASELINE INTERFEROMETRIC SETI EXPERIMENT

    SciTech Connect

    Rampadarath, H.; Morgan, J. S.; Tingay, S. J.; Trott, C. M.

    2012-08-15

    The first Search for Extra-Terrestrial Intelligence (SETI) conducted with very long baseline interferometry (VLBI) is presented. By consideration of the basic principles of interferometry, we show that VLBI is efficient at discriminating between SETI signals and human generated radio frequency interference (RFI). The target for this study was the star Gliese 581, thought to have two planets within its habitable zone. On 2007 June 19, Gliese 581 was observed for 8 hr at 1230-1544 MHz with the Australian Long Baseline Array. The data set was searched for signals appearing on all interferometer baselines above five times the noise limit. A total of 222 potential SETI signals were detected and by using automated data analysis techniques were ruled out as originating from the Gliese 581 system. From our results we place an upper limit of 7 MW Hz{sup -1} on the power output of any isotropic emitter located in the Gliese 581 system within this frequency range. This study shows that VLBI is ideal for targeted SETI including follow-up observations. The techniques presented are equally applicable to next-generation interferometers, such as the long baselines of the Square Kilometre Array.

  5. The First Very Long Baseline Interferometric SETI Experiment

    NASA Astrophysics Data System (ADS)

    Rampadarath, H.; Morgan, J. S.; Tingay, S. J.; Trott, C. M.

    2012-08-01

    The first Search for Extra-Terrestrial Intelligence (SETI) conducted with very long baseline interferometry (VLBI) is presented. By consideration of the basic principles of interferometry, we show that VLBI is efficient at discriminating between SETI signals and human generated radio frequency interference (RFI). The target for this study was the star Gliese 581, thought to have two planets within its habitable zone. On 2007 June 19, Gliese 581 was observed for 8 hr at 1230-1544 MHz with the Australian Long Baseline Array. The data set was searched for signals appearing on all interferometer baselines above five times the noise limit. A total of 222 potential SETI signals were detected and by using automated data analysis techniques were ruled out as originating from the Gliese 581 system. From our results we place an upper limit of 7 MW Hz-1 on the power output of any isotropic emitter located in the Gliese 581 system within this frequency range. This study shows that VLBI is ideal for targeted SETI including follow-up observations. The techniques presented are equally applicable to next-generation interferometers, such as the long baselines of the Square Kilometre Array.

  6. The OLYMPUS Experiment Simulation

    NASA Astrophysics Data System (ADS)

    Schmidt, Axel

    2013-04-01

    The OLYMPUS Experiment aims to measure the ratio of electron-proton to positron-proton elastic scattering cross-sections to better than 1% systematic uncertainty. Achieving this goal requires a precise understanding of a wide range of systematic effects, such as the radiative corrections internal to the reaction, the varying acceptance of the detector aparatus, and efficiency of the tracking algorithms. A detailed Geant4 simulation of the OLYMPUS experiment has been developed to study these effects, and using the Monte Carlo method, properly account for their convolution. Radiative corrections are applied by the event generator, whose events are propagated through the simulation. Simulated detector signals are produced with identical format to the raw OLYMPUS data, so that simulated data can be processed using the same analysis software. The simulation, therefore, serves as a benchmark for comparison with the final OLYMPUS results. A discussion of the radiative corrections procedure and an overview of the simulation will be presented. This work is supported by DOE Grant DE-FG02-94ER40818.

  7. Reactive flow modeling of small scale detonation failure experiments for a baseline non-ideal explosive

    NASA Astrophysics Data System (ADS)

    Kittell, David E.; Cummock, Nick R.; Son, Steven F.

    2016-08-01

    Small scale characterization experiments using only 1-5 g of a baseline ammonium nitrate plus fuel oil (ANFO) explosive are discussed and simulated using an ignition and growth reactive flow model. There exists a strong need for the small scale characterization of non-ideal explosives in order to adequately survey the wide parameter space in sample composition, density, and microstructure of these materials. However, it is largely unknown in the scientific community whether any useful or meaningful result may be obtained from detonation failure, and whether a minimum sample size or level of confinement exists for the experiments. In this work, it is shown that the parameters of an ignition and growth rate law may be calibrated using the small scale data, which is obtained from a 35 GHz microwave interferometer. Calibration is feasible when the samples are heavily confined and overdriven; this conclusion is supported with detailed simulation output, including pressure and reaction contours inside the ANFO samples. The resulting shock wave velocity is most likely a combined chemical-mechanical response, and simulations of these experiments require an accurate unreacted equation of state (EOS) in addition to the calibrated reaction rate. Other experiments are proposed to gain further insight into the detonation failure data, as well as to help discriminate between the role of the EOS and reaction rate in predicting the measured outcome.

  8. First epoch measurements by Mark III VLBI of the San Andreas Fault experiment baseline

    SciTech Connect

    Ryan, J.W.

    1985-08-01

    The 883-km-long San Andreas Fault Experiment (SAFE) baseline between Quincy in northern California and Monument Peak in southern California spans the San Andreas Fault in a way designed to measure motion between the North American and the Pacific Plates. This baseline and a closely related baseline have been measured with the satellite laser ranging techniques (SLR) for over 10 years. The baseline was measured with the very-long-baseline interferometry (VLBI) technique to confirm or reject the results already obtained from SLR.

  9. Natural or Simulated Ponds: An Environmental Baseline Study.

    ERIC Educational Resources Information Center

    Exline, Joseph D.

    1978-01-01

    Presents methods for analyzing soil and water samples in this classroom. Includes a classroom diagram, a listing of suggested materials, and the procedures for a classroom simulated pond. Relates classroom activities to work at a natural pond. (MA)

  10. SRNL RADIONUCLIDE FIELD LYSIMETER EXPERIMENT: BASELINE CONSTRUCTION AND IMPLEMENTATION

    SciTech Connect

    Roberts, K.; Kaplan, D.; Bagwell, L.; Powell, B.; Almond, P.; Emerson, H.; Hixon, A.; Jablonski, J.; Buchanan, C.; Waterhouse, T.

    2012-10-17

    The purpose of this document is to compile information regarding experimental design, facility design, construction, radionuclide source preparation, and path forward for the ten year Savannah River National Laboratory (SRNL) Radionuclide Field Lysimeter Experiment at the Savannah River Site (SRS). This is a collaborative effort by researchers at SRNL and Clemson University. The scientific objectives of this study are to: Study long-term radionuclide transport under conditions more representative of vadose zone conditions than laboratory experiments; Provide more realistic quantification of radionuclide transport and geochemistry in the vadose zone, providing better information pertinent to radioactive waste storage solutions than presently exists; Reduce uncertainty and improve justification for geochemical models such as those used in performance assessments and composite analyses.

  11. Stellar intensity interferometry over kilometer baselines: laboratory simulation of observations with the Cherenkov Telescope Array

    NASA Astrophysics Data System (ADS)

    Dravins, Dainis; Lagadec, Tiphaine

    2014-07-01

    A long-held astronomical vision is to realize diffraction-limited optical aperture synthesis over kilometer baselines. This will enable imaging of stellar surfaces and their environments, show their evolution over time, and reveal interactions of stellar winds and gas flows in binary star systems. An opportunity is now opening up with the large telescope arrays primarily erected for measuring Cherenkov light in air induced by gamma rays. With suitable software, such telescopes could be electronically connected and used also for intensity interferometry. With no optical connection between the telescopes, the error budget is set by the electronic time resolution of a few nanoseconds. Corresponding light-travel distances are on the order of one meter, making the method practically insensitive to atmospheric turbulence or optical imperfections, permitting both very long baselines and observing at short optical wavelengths. Theoretical modeling has shown how stellar surface images can be retrieved from such observations and here we report on experimental simulations. In an optical laboratory, artificial stars (single and double, round and elliptic) are observed by an array of telescopes. Using high-speed photon-counting solid-state detectors and real-time electronics, intensity fluctuations are cross correlated between up to a hundred baselines between pairs of telescopes, producing maps of the second-order spatial coherence across the interferometric Fourier-transform plane. These experiments serve to verify the concepts and to optimize the instrumentation and observing procedures for future observations with (in particular) CTA, the Cherenkov Telescope Array, aiming at order-of-magnitude improvements of the angular resolution in optical astronomy.

  12. The Science and Strategy for Phasing of the Long-Baseline Neutrino Experiment

    SciTech Connect

    Diwan, Milind V.

    2012-05-22

    This note is about the principles behind a phased plan for realizing a Long-Baseline Neutrino Experiment(LBNE) in the U.S.. The most important issue that must be resolved is the direction of the first phase of the experiment. Based on both scientific and programmatic considerations, the U.S. should pursue the best option for accelerator neutrino physics, which is the longer baseline towards Homestake with an optimizedbroadband intense beam.

  13. REPORT OF THE US LONG BASELINE NEUTRINO EXPERIMENT STUDY.

    SciTech Connect

    BARGER,V.; FINLEY, D.; LAUGHTON, C.; PORDES, S.; MARCHIONNI, A.; RAMEIKA, R.; SAOULIDOU, N.; ZWASKA, R.; BISHAI, M.; DIWAN, M.; DIERCKXSENS, M.; KIRK, H.; KAHN, S.; SIMOS, N.; MARCIANO, W.; PARSA, Z.; VIREN, B.; ET AL.

    2007-01-01

    This report provides the results of an extensive and important study of the potential for a U.S. scientific program that will extend our knowledge of neutrino oscillations well beyond what can be anticipated from ongoing and planned experiments worldwide. The program examined here has the potential to provide the U.S. particle physics community with world leading experimental capability in this intensely interesting and active field of fundamental research. Furthermore, this capability is not likely to be challenged anywhere else in the world for at least two decades into the future. The present study was initially commissioned in April 2006 by top research officers of Brookhaven National Laboratory and Fermilab and, as the study evolved, it also provides responses to questions formulated and addressed to the study group by the Neutrino Scientific Advisory Committee (NuSAG) of the U.S. DOE and NSF. The participants in the study, its Charge and history, plus the study results and conclusions are provided in this report and its appendices. A summary of the conclusions is provided in the Executive Summary.

  14. Indoor air quality impacts of residential HVAC systems. Phase 2.a report: Baseline and preliminary simulations

    SciTech Connect

    Emmerich, S.J.; Persily, A.K.

    1995-01-01

    NIST is performing whole building airflow and contaminant dispersal computer simulations with the program CONTAM93 to assess the ability of modifications of central forced-air heating and cooling systems to control pollutant sources relevant to the residential environment. The report summarizes the results of Phase II.A of this project, which consisted of three major efforts: baseline simulations of contaminant levels without indoor air quality (IAQ) controls, design of the IAQ control retrofits, and preliminary simulations of contaminant levels with the IAQ control retrofits. In Phase II.B of the study, all of the baseline cases will be modified to incorporate the IAQ control retrofits. The retrofit results will then be compared to the baseline results to evaluate the effectiveness of the retrofits.

  15. OscSNS: A Precision Short-Baseline Neutrino Oscillation Experiment

    NASA Astrophysics Data System (ADS)

    Louis, William

    2012-03-01

    Short baseline neutrino experiments are consistent with neutrino oscillations at a δm^2 of approximately 1 eV^2, and world neutrino and antineutrino data fit reasonably well to a 3+2 (active+sterile) neutrino oscillation model with CP violation. The OscSNS experiment at ORNL would be able to make precision short-baseline neutrino oscillation measurements and prove that sterile neutrinos exist. The OscSNS experiment will be described and the corresponding neutrino oscillation sensitivities will be discussed.

  16. Effects of baseline conditions on the simulated hydrologic response to projected climate change

    USGS Publications Warehouse

    Koczot, Kathryn M.; Markstrom, Steven L.; Hay, Lauren E.

    2011-01-01

    Changes in temperature and precipitation projected from five general circulation models, using one late-twentieth-century and three twenty-first-century emission scenarios, were downscaled to three different baseline conditions. Baseline conditions are periods of measured temperature and precipitation data selected to represent twentieth-century climate. The hydrologic effects of the climate projections are evaluated using the Precipitation-Runoff Modeling System (PRMS), which is a watershed hydrology simulation model. The Almanor Catchment in the North Fork of the Feather River basin, California, is used as a case study. Differences and similarities between PRMS simulations of hydrologic components (i.e., snowpack formation and melt, evapotranspiration, and streamflow) are examined, and results indicate that the selection of a specific time period used for baseline conditions has a substantial effect on some, but not all, hydrologic variables. This effect seems to be amplified in hydrologic variables, which accumulate over time, such as soil-moisture content. Results also indicate that uncertainty related to the selection of baseline conditions should be evaluated using a range of different baseline conditions. This is particularly important for studies in basins with highly variable climate, such as the Almanor Catchment.

  17. Super-NOnuA: A Long-baseline neutrino experiment with two off-axis detectors

    SciTech Connect

    Mena Requejo, Olga; Palomares-Ruiz, Sergio; Pascoli, Silvia; /CERN

    2005-04-01

    Establishing the neutrino mass hierarchy is one of the fundamental questions that will have to be addressed in the next future. Its determination could be obtained with long-baseline experiments but typically suffers from degeneracies with other neutrino parameters. We consider here the NOvA experiment configuration and propose to place a second off-axis detector, with a shorter baseline, such that, by exploiting matter effects, the type of neutrino mass hierarchy could be determined with only the neutrino run. We show that the determination of this parameter is free of degeneracies, provided the ratio L/E, where L the baseline and E is the neutrino energy, is the same for both detectors.

  18. Baseline geoenvironmental experiments for in-situ soil transformation by plasma torch

    SciTech Connect

    Beaver, J.R.; Mayne, P.W.

    1995-12-31

    The advent of the nontransferred plasma arc torch has implicated a range of in-situ geoenvironmental applications that can revolutionize methods of ground modification and field remediation of contaminated sites. With reverse polarity nontransferred arc type plasma torches, temperatures of 4,000 C to 7,000 C can be directed at specific targets of contaminated soil or waste. At these extreme temperatures, all organic materials within the soil undergo pyrolysis, while the bulk composition is transformed into a magma that subsequently cools to form a vitrified mass resembling volcanic obsidian or a dense partially crystalline material resembling microcrystalline igneous rock. Simulations of in-situ transformation of soil have been conducted using both 100-kW and 240-kW torches to alter clay, silty sand, and sand in chamber tests. Although these materials are primarily composed of silica and alumina oxides having melting temperatures of 1,100 C to 1,600 C, the formation of a spheroidal magma core occurred within the first five minutes of exposure to the plasma flame. Experiments were conducted to quantify the improved engineering properties that occur after transformation and to demonstrate the relative effects of power level, water content, and soil type on the size and strength of the altered material. The ongoing research also serves as a baseline study for further experimentation that will focus on the in-situ remediation of soils with varied contaminants.

  19. Baseline optimization for the measurement of C P violation, mass hierarchy, and θ23 octant in a long-baseline neutrino oscillation experiment

    NASA Astrophysics Data System (ADS)

    Bass, M.; Bishai, M.; Cherdack, D.; Diwan, M.; Djurcic, Z.; Hernandez, J.; Lundberg, B.; Paolone, V.; Qian, X.; Rameika, R.; Whitehead, L.; Wilson, R. J.; Worcester, E.; Zeller, G.

    2015-03-01

    Next-generation long-baseline electron neutrino appearance experiments will seek to discover C P violation, determine the mass hierarchy and resolve the θ23 octant. In light of the recent precision measurements of θ13, we consider the sensitivity of these measurements in a study to determine the optimal baseline, including practical considerations regarding beam and detector performance. We conclude that a detector at a baseline of at least 1000 km in a wide-band muon neutrino beam is the optimal configuration.

  20. The effect of tracking network configuration on GPS baseline estimates for the CASA Uno experiment

    NASA Technical Reports Server (NTRS)

    Wolf, S. Kornreich; Dixon, T. H.; Freymueller, J. T.

    1990-01-01

    The effect of the tracking network on long (greater than 100 km) GPS baseline estimates was estimated using various subsets of the global tracking network initiated by the first Central and South America (CASA Uno) experiment. It was found that best results could be obtained with a global tacking network consisting of three U.S. stations, two sites in the southwestern Pacific, and two sites in Europe. In comparison with smaller subsets, this global network improved the baseline repeatability, the resolution of carrier phase cycle ambiguities, and formal errors of the orbit estimates.

  1. Experimental parameters for a reactor antineutrino experiment at very short baselines

    NASA Astrophysics Data System (ADS)

    Heeger, K. M.; Tobin, M. N.; Littlejohn, B. R.; Mumm, H. P.

    2013-04-01

    Reactor antineutrinos are used to study neutrino oscillation, search for signatures of nonstandard neutrino interactions, and monitor reactor operation for safeguard applications. The flux and energy spectrum of reactor antineutrinos can be predicted from the decays of the nuclear fission products. A comparison of recent reactor calculations with past measurements at baselines of 10-100 m suggests a 7.2% deficit. Precision measurements of reactor antineutrinos at very short baselines O(1-10m) can be used to probe this anomaly and search for possible oscillations into sterile neutrino species. This paper studies the experimental requirements for a new reactor antineutrino measurement at very short baselines and calculates the sensitivity of various scenarios. We conclude that, given proper site optimization, detector design, and background reduction, an experiment at a typical research reactor can provide 5σ discovery potential for the favored oscillation parameter space with 3 years of detector live time.

  2. Fault-free validation of a fault-tolerant multiprocessor: Baseline experiments and workoad implementation

    NASA Technical Reports Server (NTRS)

    Feather, F.; Siewiorek, D.; Segall, Z.

    1986-01-01

    In the future, aircraft employing active control technology must use highly reliable multiprocessors in order to achieve flight safety. Such computers must be experimentally validated before they are deployed. This project outlines a methodology for doing fault-free validation of reliable multiprocessors. The methodology begins with baseline experiments, which test single phenomenon. As experiments progress, tools for performance testing are developed. This report presents the results of interrupt baseline experiments performed on the Fault-Tolerant Multiprocessor (FTMP) at NASA-Langley's AIRLAB. Interrupt-causing excepting conditions were tested, and several were found to have unimplemented interrupt handling software while one had an unimplemented interrupt vector. A synthetic workload model for realtime multiprocessors is then developed as an application level performance analysis tool. Details of the workload implementation and calibration are presented. Both the experimental methodology and the synthetic workload model are general enough to be applicable to reliable multi-processors besides FTMP.

  3. PROSPECT: A Short-baseline Reactor Precision Spectrum and Oscillation Experiment

    NASA Astrophysics Data System (ADS)

    Langford, Thomas; Prospect Collaboration

    2015-10-01

    PROSPECT is a phased experiment consisting of segmented Li-loaded liquid scintillator antineutrino detectors designed to probe short-baseline neutrino oscillations and precisely measure the reactor antineutrino spectrum. The experiment will be located at the High Flux Isotope Reactor (HFIR) at Oak Ridge National Lab. The first phase is a movable 2.5 tonne detector located 7-9 m from the compact, highly enriched uranium (HEU) core. Over the past two years, PROSPECT has deployed multiple prototype detectors at HFIR to understand the local background environment and demonstrate active and passive background rejection. Measuring the neutrino spectrum from 235U will give insight to the recent spectral discrepancies and provide an important benchmark for future reactor experiments. As a high statistics experiment, PROSPECT will probe the sterile neutrino best-fit region within one year of operation at HFIR.

  4. Nonstandard interactions spoiling the C P violation sensitivity at DUNE and other long baseline experiments

    NASA Astrophysics Data System (ADS)

    Masud, Mehedi; Mehta, Poonam

    2016-07-01

    It is by now established that neutrino oscillations occur due to nonzero masses and parameters in the leptonic mixing matrix. The extraction of oscillation parameters may be complicated due to subleading effects such as nonstandard neutrino interactions and one needs to have a fresh look how a particular parameter value is inferred from experimental data. In the present work, we focus on an important parameter entering the oscillation framework-the leptonic C P -violating phase δ , about which we know very little. We demonstrate that the sensitivity to C P violation gets significantly impacted due to nonstandard neutrino interaction effects for the upcoming long baseline experiment, Deep Underground Neutrino Experiment. We also draw a comparison with the sensitivities of other ongoing neutrino beam experiments such as NO ν A and T2K as well as a future generation experiment, T2HK.

  5. Measuring the mass of a sterile neutrino with a very short baseline reactor experiment

    NASA Astrophysics Data System (ADS)

    Latimer, D. C.; Escamilla, J.; Ernst, D. J.

    2007-04-01

    An analysis of the world's neutrino oscillation data, including sterile neutrinos, [M. Sorel, C. M. Conrad, and M. H. Shaevitz, Phys. Rev. D 70, 073004 (2004)] found a peak in the allowed region at a mass-squared difference Δm2≅0.9eV2. We trace its origin to harmonic oscillations in the electron survival probability Pee as a function of L/E, the ratio of baseline to neutrino energy, as measured in the near detector of the Bugey experiment. We find a second occurrence for Δm2≅1.9eV2. We point out that the phenomenon of harmonic oscillations of Pee as a function of L/E, as seen in the Bugey experiment, can be used to measure the mass-squared difference associated with a sterile neutrino in the range from a fraction of an eV2 to several eV2 (compatible with that indicated by the LSND experiment), as well as measure the amount of electron-sterile neutrino mixing. We observe that the experiment is independent, to lowest order, of the size of the reactor and suggest the possibility of a small reactor with a detector sitting at a very short baseline.

  6. Validation of a fault-tolerant multiprocessor: Baseline experiments and workload implementation

    NASA Technical Reports Server (NTRS)

    Feather, Frank; Siewiorek, Daniel; Segall, Zary

    1985-01-01

    In the future, aircraft must employ highly reliable multiprocessors in order to achieve flight safety. Such computers must be experimentally validated before they are deployed. This project outlines a methodology for validating reliable multiprocessors. The methodology begins with baseline experiments, which tests a single phenomenon. As experiments progress, tools for performance testing are developed. The methodology is used, in part, on the Fault Tolerant Multiprocessor (FTMP) at NASA-Langley's AIRLAB facility. Experiments are designed to evaluate the fault-free performance of the system. Presented are the results of interrupt baseline experiments performed on FTMP. Interrupt causing exception conditions were tested, and several were found to have unimplemented interrupt handling software while one had an unimplemented interrupt vector. A synthetic workload model for realtime multiprocessors is then developed as an application level performance analysis tool. Details of the workload implementation and calibration are presented. Both the experimental methodology and the synthetic workload model are general enough to be applicable to reliable multiprocessors beside FTMP.

  7. Measuring the mass of a sterile neutrino with a very short baseline reactor experiment

    SciTech Connect

    Latimer, D. C.; Escamilla, J.; Ernst, D. J.

    2007-04-15

    An analysis of the world's neutrino oscillation data, including sterile neutrinos, [M. Sorel, C. M. Conrad, and M. H. Shaevitz, Phys. Rev. D 70, 073004 (2004)] found a peak in the allowed region at a mass-squared difference {delta}m{sup 2} congruent with 0.9 eV{sup 2}. We trace its origin to harmonic oscillations in the electron survival probability P{sub ee} as a function of L/E, the ratio of baseline to neutrino energy, as measured in the near detector of the Bugey experiment. We find a second occurrence for {delta}m{sup 2} congruent with 1.9 eV{sup 2}. We point out that the phenomenon of harmonic oscillations of P{sub ee} as a function of L/E, as seen in the Bugey experiment, can be used to measure the mass-squared difference associated with a sterile neutrino in the range from a fraction of an eV{sup 2} to several eV{sup 2} (compatible with that indicated by the LSND experiment), as well as measure the amount of electron-sterile neutrino mixing. We observe that the experiment is independent, to lowest order, of the size of the reactor and suggest the possibility of a small reactor with a detector sitting at a very short baseline.

  8. Light sterile neutrinos, lepton number violating interactions and short baseline neutrino experiments

    NASA Astrophysics Data System (ADS)

    Babu, K. S.; McKay, D. W.; Mocioiu, Irina; Pakvasa, Sandip

    2016-06-01

    We develop the consequences of introducing a purely leptonic, non-standard interaction (NSI) ΔL = 2, four-fermion effective Lagrangian and standard model neutrino mixing with a fourth, sterile neutrino in the analysis of short-baseline, neutrino experiments. We focus on the muon decay at rest (DAR) results from the Liquid Scintillation Neutrino Experiment (LSND) and the Karlsruhe and Rutherford medium Energy Neutrino Experiment (KARMEN), seeking a reconciliation between the two. Both v¯e appearance from v¯μ oscillation and v¯e survival after production from NSI decay of the µ+ contribute to the expected signal. This is a unique feature of our scheme. We comment on further implications of the lepton number violating interaction and sterile neutrino-standard neutrino mixing.

  9. Nonstandard interaction effects on neutrino parameters at medium-baseline reactor antineutrino experiments

    NASA Astrophysics Data System (ADS)

    Ohlsson, Tommy; Zhang, He; Zhou, Shun

    2014-01-01

    Precision measurements of leptonic mixing parameters and the determination of the neutrino mass hierarchy are the primary goals of the forthcoming medium-baseline reactor antineutrino experiments, such as JUNO and RENO-50. In this work, we investigate the impact of nonstandard neutrino interactions (NSIs) on the measurements of {sin2 θ12,Δm212} and {sin2 θ13,Δm312}, and on the sensitivity to the neutrino mass hierarchy, at the medium-baseline reactor experiments by assuming a typical experimental setup. It turns out that the true mixing parameter sin2 θ12 can be excluded at a more than 3σ level if the NSI parameter ɛ or ɛ is as large as 2% in the most optimistic case. However, the discovery reach of NSI effects has been found to be small, and depends crucially on the CP-violating phases. Finally, we show that NSI effects could enhance or reduce the discrimination power of the JUNO and RENO-50 experiments between the normal and inverted neutrino mass hierarchies.

  10. Investigation of neutrino oscillations in the T2k long-baseline accelerator experiment

    SciTech Connect

    Izmaylov, A. O. Yershov, N. V.; Kudenko, Yu. G.; Matveev, V. A.; Mineev, O. V.; Musienko, Yu. V.; Khabibulliun, M. M.; Khotjantsev, A. N.; Shaykhiev, A. T.

    2012-02-15

    High-sensitivity searches for transitions of muon neutrinos to electron neutrinos are the main task of the T2K (Tokai-to-Kamioka) second-generation long-baseline accelerator neutrino experiment. The present article is devoted to describing basic principles of T2K, surveying experimental apparatuses that it includes, and considering in detail the muon-range detector (SMRD) designed and manufactured by a group of physicists from the Institute of Nuclear Research (Russian Academy of Sciences, Moscow). The results of the first measurements with a neutrino beam are presented, and plans for the near future are discussed.

  11. Studies of earth simulation experiments

    NASA Technical Reports Server (NTRS)

    Hart, J. E.

    1976-01-01

    The low gravity environment of earth orbit offers the potential for performing experiments involving baroclinic Geophysical Fluid Dynamics (GFD) on spherical surfaces. These experiments in turn have the potential for providing deeper understanding of large scale planetary and solar circulations. However, to perform these experiments, one requires an experimental technique whereby a radially directed body force can be generated to simulate a radial gravitational force field. One viable technique is the use of dielectric fluids with temperature dependent dielectric permittivity in a radially directed electric field. Application of the Boussinesq approximation to the equations of motion for this system and restrictions on the size of certain electrodynamic terms in the energy equations yields a set of equations which are analogous to the equations of motions of geophysical systems like the earth's atmosphere on term by term basis. The theoretical design of GFD experiments for performance in earth orbit are described along with results of preliminary tests of a prototype.

  12. Modeling and Simulation of Offshore Wind Power Platform for 5 MW Baseline NREL Turbine.

    PubMed

    Roni Sahroni, Taufik

    2015-01-01

    This paper presents the modeling and simulation of offshore wind power platform for oil and gas companies. Wind energy has become the fastest growing renewable energy in the world and major gains in terms of energy generation are achievable when turbines are moved offshore. The objective of this project is to propose new design of an offshore wind power platform. Offshore wind turbine (OWT) is composed of three main structures comprising the rotor/blades, the tower nacelle, and the supporting structure. The modeling analysis was focused on the nacelle and supporting structure. The completed final design was analyzed using finite element modeling tool ANSYS to obtain the structure's response towards loading conditions and to ensure it complies with guidelines laid out by classification authority Det Norske Veritas. As a result, a new model of the offshore wind power platform for 5 MW Baseline NREL turbine was proposed. PMID:26550605

  13. Modeling and Simulation of Offshore Wind Power Platform for 5 MW Baseline NREL Turbine

    PubMed Central

    Roni Sahroni, Taufik

    2015-01-01

    This paper presents the modeling and simulation of offshore wind power platform for oil and gas companies. Wind energy has become the fastest growing renewable energy in the world and major gains in terms of energy generation are achievable when turbines are moved offshore. The objective of this project is to propose new design of an offshore wind power platform. Offshore wind turbine (OWT) is composed of three main structures comprising the rotor/blades, the tower nacelle, and the supporting structure. The modeling analysis was focused on the nacelle and supporting structure. The completed final design was analyzed using finite element modeling tool ANSYS to obtain the structure's response towards loading conditions and to ensure it complies with guidelines laid out by classification authority Det Norske Veritas. As a result, a new model of the offshore wind power platform for 5 MW Baseline NREL turbine was proposed. PMID:26550605

  14. Alcator C-Mod Experiments in Support of the ITER Baseline 15 MA Scenario

    SciTech Connect

    C Kessel, et al

    2013-05-07

    Experiments on Alcator C-Mod have addressed several issues for the ITER 15 MA baseline scenario from 2009-2012. Rampup studies show ICRF can save significant V-s, and that an H-mode in the ramp can be utilized to save 50% more. ICRF modifications to li(1) are minimal, although the Te profile is peaked relative to ohmic in the plasma center, and alter sawtooth onset times. Rampdown studies show H-modes can be routinely sustained, avoiding an OH coil over-current associated with the H-L transition, that fast rampdowns are preferred, the density drops with Ip, and that the H-L transition occurs at Ploss/Pthr,LH ~ 1.0-1.3 at n/nGr ~ 0.85. Flattop plasmas targeting ITER baseline parameters have been sustained for 20 τE or 8-13 τCR, but only reach H98 ~ 0.6 at n/nGr = 0.85, rising to 0.9 at n/nGr = 0.65.

  15. Large-θ 13 perturbation theory of neutrino oscillation for long-baseline experiments

    NASA Astrophysics Data System (ADS)

    Asano, Katsuhiro; Minakata, Hisakazu

    2011-06-01

    The Cervera et al. formula, the best known approximate formula of neutrino oscillation probability for long-baseline experiments, can be regarded as a second-order perturbative formula with small expansion parameter ɛ ≡ ∆ m {21/2} ∆ m {31/2} ≃ 0 .03 under the 21assumption s 13 ≃ ɛ. If θ 13 is large, as suggested by a candidate ν e event at T2K as well as the recent global analyses, higher order corrections of s 13 to the formula would be needed for better accuracy. We compute the corrections systematically by formulating a perturbative framework by taking θ 13 as {s_{13}} ˜ sqrt { in } ˜eq 0.18 , which guarantees its validity in a wide range of θ 13 below the Chooz limit. We show on general ground that the correction terms must be of order ɛ2. Yet, they nicely fill the mismatch between the approximate and the exact formulas at low energies and relatively long baselines. General theorems are derived which serve for better understanding of δ-dependence of the oscillation probability. Some interesting implications of the large θ 13 hypothesis are discussed.

  16. Baseline monitoring using aircraft laser ranging. [spaceborne laser simulation and aircraft laser tracking

    NASA Technical Reports Server (NTRS)

    Krabill, W. B.; Hoge, F. E.; Martin, C. F.

    1982-01-01

    The use of aircraft laser ranging for the determination of baselines between ground based retroreflectors was investigated via simulations and with tests at Wallops Flight Center using the Airborne Oceanographic Lidar (AOL) on the Wallops C-54 aircraft ranging to a reflector array deployed around one of the Wallops runways. The aircraft altitude and reflector spacing were chosen on the basis of scaled down modeling of spacecraft tracking from 1000 km of reflectors separated by some 52 km, or of high altitude (10 km) aircraft tracking of reflectors separated by some 500 m. Aircraft altitudes flown for different passes across the runway reflector array varied from 800 m to 1350 m, with 32 reflectors deployed over an approximtely 300 m x 500 m ground pattern. The AOL transmitted 400 pulses/sec with a scan rate of 5/sec in a near circular pattern, so that the majority of the pulses were reflected by the runway surface or its environs rather than by retroreflectors. The return pulse characteristics clearly showed the high reflectivity of portions of the runway, with several returns indistinguishable in amplitude from reflector returns. For each pass across the reflector field, typically six to ten reflector hits were identified, consistent with that predicted by simulations and the observed transmitted elliptical pulse size.

  17. Background Characterization for PROSPECT: a US Short-baseline Neutrino Oscillation Experiment

    NASA Astrophysics Data System (ADS)

    Langford, Thomas

    2014-03-01

    Segmented antineutrino detectors placed near compact research reactors provide an excellent opportunity to probe short-baseline neutrino oscillations and precisely measure the reactor antineutrino spectrum. The PROSPECT collaboration has developed a conceptual design for an experiment covering the favored reactor anomaly parameter space using two detectors located within 4-20 m of an existing reactor. Research reactors offer the benefits of compact cores, distinct reactor-off periods, and single-isotope fuel. However, they are typically located at ground level, providing little to no overburden to shield detectors. This talk will present the background requirements of the PROSPECT experiment and discuss feasibility studies that have been performed for three potential locations: NIST, INL, and ORNL. Two fast neutron detectors, a muon telescope, and HPGE and NaI gamma detectors have been deployed at the sites to measure reactor-related and cosmogenic backgrounds. The results of background measurements at each site during reactor operation and shutdown will be shown. Additionally, the planned techniques to reduce the impact of each background on the physics reach of the full experiment will also be discussed.

  18. Simulation of the DRIFT Experiment

    NASA Astrophysics Data System (ADS)

    Hyatt, Matt; Ayad, Rachid; Hanson-Hart, Zach; Katz-Hyman, Moshe; Posner, Aaron; Martoff, C. J.

    2003-04-01

    The DRIFT Experiment [1] is an underground search for WIMP Dark Matter using a novel detector invented for this purpose: the Negative Ion TPC (NITPC). To aid in interpreting the results, a simulation code system has been developed. The system uses the CERNLIB program GEANT [2] and the NRC package EGS4 [3] to simulate particle interactions in the detector. These are linked directly to the CERNLIB program GARFIELD, which simulates signal production in the NITPC. Finally the GARFIELD output is converted into the format of the DRIFT DAQ for presentation to the analysis code. The physics and software issues dealt with in this development will be discussed. [1] Low Pressure Negative Ion TPC for Dark Matter Search. D. P. Snowden-Ifft, C. J. Martoff, J. M. Burwell, Phys Rev. D. Rapid Comm. 61, 101301 (2000) [2] GEANT Manual, CERN Program Library Long Writeup W5013, Copyright CERN, Geneva, 1993 . [3] EGS4, National Research Council, Canada. Note PIRS-701. http://www.irs.inms.nrc.ca/inms/irs/EGS4/get_egs4.html . [4] GARFIELD Manual, version 7.04, CERN Program Library Long Writeup W5050, Copyright CERN, Geneva, 2001 .

  19. Space Station Simulation Computer System (SCS) study for NASA/MSFC. Volume 1: Baseline architecture report

    NASA Technical Reports Server (NTRS)

    1990-01-01

    NASA's Space Station Freedom Program (SSFP) planning efforts have identified a need for a payload training simulator system to serve as both a training facility and as a demonstrator to validate operational concepts. The envisioned MSFC Payload Training Complex (PTC) required to meet this need will train the Space Station payload scientists, station scientists, and ground controllers to operate the wide variety of experiments that will be onboard the Space Station Freedom. The Simulation Computer System (SCS) is made up of the computer hardware, software, and workstations that will support the Payload Training Complex at MSFC. The purpose of this SCS Study is to investigate issues related to the SCS, alternative requirements, simulator approaches, and state-of-the-art technologies to develop candidate concepts and designs.

  20. Space Station Simulation Computer System (SCS) study for NASA/MSFC. Volume 2: Baseline architecture report

    NASA Technical Reports Server (NTRS)

    1990-01-01

    NASA's Space Station Freedom Program (SSFP) planning efforts have identified a need for a payload training simulator system to serve as both a training facility and as a demonstrator to validate operational concepts. The envisioned MSFC Payload Training Complex (PTC) required to meet this need will train the Space Station payload scientists, station scientists, and ground controllers to operate the wide variety of experiments that will be onboard the Space Station Freedom. The Simulation Computer System (SCS) is the computer hardware, software, and workstations that will support the Payload Training Complex at MSFC. The purpose of this SCS Study is to investigate issues related to the SCS, alternative requirements, simulator approaches, and state-of-the-art technologies to develop candidate concepts and designs.

  1. Constraint on neutrino decay with medium-baseline reactor neutrino oscillation experiments

    NASA Astrophysics Data System (ADS)

    Abrahão, Thamys; Minakata, Hisakazu; Nunokawa, Hiroshi; Quiroga, Alexander A.

    2015-11-01

    The experimental bound on lifetime of ν 3, the neutrino mass eigenstate with the smallest ν e component, is much weaker than those of ν 1 and ν 2 by many orders of magnitude to which the astrophysical constraints apply. We argue that the future reactor neutrino oscillation experiments with medium-baseline (˜50 km), such as JUNO or RENO-50, has the best chance of placing the most stringent constraint on ν3 lifetime among all neutrino experiments which utilize the artificial source neutrinos. Assuming decay into invisible states, we show by a detailed χ 2 analysis that the ν 3 lifetime divided by its mass, τ 3 /m 3, can be constrained to be τ 3 /m 3 > 7 .5 (5 .5) × 10-11 s/eV at 95% (99%) C.L. by 100 kt·years exposure by JUNO. It may be further improved to the level comparable to the atmospheric neutrino bound by its longer run. We also discuss to what extent ν 3 decay affects mass-ordering determination and precision measurements of the mixing parameters.

  2. The Transliminal Brain at Rest: Baseline EEG, Unusual Experiences, and Access to Unconscious Mental Activity

    PubMed Central

    Fleck, Jessica I.; Green, Deborah L.; Stevenson, Jennifer L.; Payne, Lisa; Bowden, Edward M.; Jung-Beeman, Mark; Kounios, John

    2008-01-01

    Transliminality reflects individual differences in the threshold at which unconscious processes or external stimuli enter into consciousness. Individuals high in transliminality possess characteristics such as magical ideation, belief in the paranormal, and creative personality traits, and also report the occurrence of manic/mystic experiences. The goal of the present research was to determine if resting brain activity differs for individuals high versus low in transliminality. We compared baseline EEG recordings (eyes-closed) between individuals high versus low in transliminality, assessed using The Revised Transliminality Scale of Lange et al. (2000). Identifying reliable differences at rest between high- and low-transliminality individuals would support a predisposition for transliminality-related traits. Individuals high in transliminality exhibited lower alpha, beta, and gamma power than individuals low in transliminality over left posterior association cortex and lower high alpha, low beta, and gamma power over the right superior temporal region. In contrast, when compared to individuals low in transliminality, individuals high in transliminality exhibited greater gamma power over the frontal-midline region. These results are consistent with prior research reporting reductions in left temporal/parietal activity, as well as the desynchronization of right temporal activity in schizotypy and related schizophrenia spectrum disorders. Further, differences between high- and low-transliminality groups extend existing theories linking altered hemispheric asymmetries in brain activity to a predisposition toward schizophrenia, paranormal beliefs, and unusual experiences. PMID:18814870

  3. The transliminal brain at rest: baseline EEG, unusual experiences, and access to unconscious mental activity.

    PubMed

    Fleck, Jessica I; Green, Deborah L; Stevenson, Jennifer L; Payne, Lisa; Bowden, Edward M; Jung-Beeman, Mark; Kounios, John

    2008-01-01

    Transliminality reflects individual differences in the threshold at which unconscious processes or external stimuli enter into consciousness. Individuals high in transliminality possess characteristics such as magical ideation, belief in the paranormal, and creative personality traits, and also report the occurrence of manic/mystic experiences. The goal of the present research was to determine if resting brain activity differs for individuals high versus low in transliminality. We compared baseline EEG recordings (eyes-closed) between individuals high versus low in transliminality, assessed using The Revised Transliminality Scale of Lange et al. (2000). Identifying reliable differences at rest between high- and low-transliminality individuals would support a predisposition for transliminality-related traits. Individuals high in transliminality exhibited lower alpha, beta, and gamma power than individuals low in transliminality over left posterior association cortex and lower high alpha, low beta, and gamma power over the right superior temporal region. In contrast, when compared to individuals low in transliminality, individuals high in transliminality exhibited greater gamma power over the frontal-midline region. These results are consistent with prior research reporting reductions in left temporal/parietal activity, as well as the desynchronization of right temporal activity in schizotypy and related schizophrenia spectrum disorders. Further, differences between high- and low-transliminality groups extend existing theories linking altered hemispheric asymmetries in brain activity to a predisposition toward schizophrenia, paranormal beliefs, and unusual experiences. PMID:18814870

  4. Long baseline neutrino oscillation experiment at the AGS. Physics design report

    SciTech Connect

    Beavis, D.; Carroll, A.; Chiang, I.; E889 Collaboration

    1995-04-01

    The authors present a design for a multi-detector long baseline neutrino oscillation experiment at the BNL AGS. It has been approved by the BNL-HENP-PAC as AGS Experiment 889. The experiment will search for oscillations in the {nu}{sub {mu}}, disappearance channel and the {nu}{sub {mu}} {leftrightarrow} {nu}{sub e} appearance channel by means of four identical neutrino detectors located 1, 3, 24, and 68km from the AGS neutrino source. Observed depletion of the {nu}{sub {mu}} flux (via quasi-elastic muon neutrino events, {nu}{sub {mu}}n {yields} {mu}{sup {minus}}p) in the far detectors not attended by an observed proportional increase of the {nu}{sub e} flux (via quasi-elastic electron neutrino events, {nu}{sub e}n {yields} e{sup {minus}}p) in those detectors will be prima facie evidence for the oscillation channel {nu}{sub {mu}} {leftrightarrow} {nu}{sub {tau}}. The experiment is directed toward exploration of the region of the neutrino oscillation parameters {Delta}m{sup 2} and sin{sup 2}2{theta}, suggested by the Kamiokande and IMB deep underground detectors but it will also explore a region more than two orders of magnitude larger than that of previous accelerator experiments. The experiment will run in a mode new to BNL. It will receive the fast extracted proton beam on the neutrino target approximately 20 hours per day when the AGS is not filling RHIC. A key aspect of the experimental design involves placing the detectors 1.5 degrees off the center line of the neutrino beam, which has the important advantage that the central value of the neutrino energy ({approx} 1 GeV) and the beam spectral shape are, to a good approximation, the same in all four detectors. The proposed detectors are massive, imaging, water Cherenkov detectors similar in large part to the Kamiokande and IMB detectors. The design has profited from their decade-long experience, and from the detector designs of the forthcoming SNO and SuperKamiokande detectors.

  5. Shedding light on LMA-dark solar neutrino solution by medium baseline reactor experiments: JUNO and RENO-50

    NASA Astrophysics Data System (ADS)

    Bakhti, P.; Farzan, Y.

    2014-07-01

    In the presence of Non-Standard neutral current Interactions (NSI) a new solution to solar neutrino anomaly with cos 2 θ 12 < 0 appears. We investigate how this solution can be tested by upcoming intermediate baseline reactor experiments, JUNO and RENO-50. We point out a degeneracy between the two solutions when both hierarchy and the θ 12 octant are flipped. We then comment on how this degeneracy can be partially lifted by long baseline experiments sensitive to matter effects such as the NOvA experiment.

  6. Exploring flavor-dependent long-range forces in long-baseline neutrino oscillation experiments

    NASA Astrophysics Data System (ADS)

    Chatterjee, Sabya Sachi; Dasgupta, Arnab; Agarwalla, Sanjib Kumar

    2015-12-01

    The Standard Model gauge group can be extended with minimal matter content by introducing anomaly free U(1) symmetry, such as L e - L μ or L e - L τ . If the neutral gauge boson corresponding to this abelian symmetry is ultra-light, then it will give rise to flavor-dependent long-range leptonic force, which can have significant impact on neutrino oscillations. For an instance, the electrons inside the Sun can generate a flavor-dependent long-range potential at the Earth surface, which can suppress the ν μ → ν e appearance probability in terrestrial experiments. The sign of this potential is opposite for anti-neutrinos, and affects the oscillations of (anti-)neutrinos in different fashion. This feature invokes fake CP-asymmetry like the SM matter effect and can severely affect the leptonic CP-violation searches in long-baseline experiments. In this paper, we study in detail the possible impacts of these long-range flavor-diagonal neutral current interactions due to L e - L μ symmetry, when (anti-)neutrinos travel from Fermilab to Homestake (1300 km) and CERN to Pyhäsalmi (2290 km) in the context of future high-precision superbeam facilities, DUNE and LBNO respectively. If there is no signal of long-range force, DUNE (LBNO) can place stringent constraint on the effective gauge coupling α eμ < 1.9 × 10-53 (7.8 × 10-54) at 90% C.L., which is almost 30 (70) times better than the existing bound from the Super-Kamiokande experiment. We also observe that if α eμ ≥ 2 × 10-52, the CP-violation discovery reach of these future facilities vanishes completely. The mass hierarchy measurement remains robust in DUNE (LBNO) if α eμ < 5 × 10-52 (10-52).

  7. Flight Technical Error Analysis of the SATS Higher Volume Operations Simulation and Flight Experiments

    NASA Technical Reports Server (NTRS)

    Williams, Daniel M.; Consiglio, Maria C.; Murdoch, Jennifer L.; Adams, Catherine H.

    2005-01-01

    This paper provides an analysis of Flight Technical Error (FTE) from recent SATS experiments, called the Higher Volume Operations (HVO) Simulation and Flight experiments, which NASA conducted to determine pilot acceptability of the HVO concept for normal operating conditions. Reported are FTE results from simulation and flight experiment data indicating the SATS HVO concept is viable and acceptable to low-time instrument rated pilots when compared with today s system (baseline). Described is the comparative FTE analysis of lateral, vertical, and airspeed deviations from the baseline and SATS HVO experimental flight procedures. Based on FTE analysis, all evaluation subjects, low-time instrument-rated pilots, flew the HVO procedures safely and proficiently in comparison to today s system. In all cases, the results of the flight experiment validated the results of the simulation experiment and confirm the utility of the simulation platform for comparative Human in the Loop (HITL) studies of SATS HVO and Baseline operations.

  8. Observation of Energy and Baseline Dependent Reactor Antineutrino Disappearance in the RENO Experiment.

    PubMed

    Choi, J H; Choi, W Q; Choi, Y; Jang, H I; Jang, J S; Jeon, E J; Joo, K K; Kim, B R; Kim, H S; Kim, J Y; Kim, S B; Kim, S Y; Kim, W; Kim, Y D; Ko, Y; Lee, D H; Lim, I T; Pac, M Y; Park, I G; Park, J S; Park, R G; Seo, H; Seo, S H; Seon, Y G; Shin, C D; Siyeon, K; Yang, J H; Yeo, I S; Yu, I

    2016-05-27

    The RENO experiment has analyzed about 500 live days of data to observe an energy dependent disappearance of reactor ν[over ¯]_{e} by comparing their prompt signal spectra measured in two identical near and far detectors. In the period between August of 2011 and January of 2013, the far (near) detector observed 31 541 (290 775) electron antineutrino candidate events with a background fraction of 4.9% (2.8%). The measured prompt spectra show an excess of reactor ν[over ¯]_{e} around 5 MeV relative to the prediction from a most commonly used model. A clear energy and baseline dependent disappearance of reactor ν[over ¯]_{e} is observed in the deficit of the observed number of ν[over ¯]_{e}. Based on the measured far-to-near ratio of prompt spectra, we obtain sin^{2}2θ_{13}=0.082±0.009(stat)±0.006(syst) and |Δm_{ee}^{2}|=[2.62_{-0.23}^{+0.21}(stat)_{-0.13}^{+0.12}(syst)]×10^{-3}  eV^{2}. PMID:27284648

  9. Observation of Energy and Baseline Dependent Reactor Antineutrino Disappearance in the RENO Experiment

    NASA Astrophysics Data System (ADS)

    Choi, J. H.; Choi, W. Q.; Choi, Y.; Jang, H. I.; Jang, J. S.; Jeon, E. J.; Joo, K. K.; Kim, B. R.; Kim, H. S.; Kim, J. Y.; Kim, S. B.; Kim, S. Y.; Kim, W.; Kim, Y. D.; Ko, Y.; Lee, D. H.; Lim, I. T.; Pac, M. Y.; Park, I. G.; Park, J. S.; Park, R. G.; Seo, H.; Seo, S. H.; Seon, Y. G.; Shin, C. D.; Siyeon, K.; Yang, J. H.; Yeo, I. S.; Yu, I.; RENO Collaboration

    2016-05-01

    The RENO experiment has analyzed about 500 live days of data to observe an energy dependent disappearance of reactor ν¯e by comparing their prompt signal spectra measured in two identical near and far detectors. In the period between August of 2011 and January of 2013, the far (near) detector observed 31 541 (290 775) electron antineutrino candidate events with a background fraction of 4.9% (2.8%). The measured prompt spectra show an excess of reactor ν¯e around 5 MeV relative to the prediction from a most commonly used model. A clear energy and baseline dependent disappearance of reactor ν¯e is observed in the deficit of the observed number of ν¯e. Based on the measured far-to-near ratio of prompt spectra, we obtain sin22 θ13=0.082 ±0.009 (stat)±0.006 (syst) and |Δ mee 2|=[2.6 2-0.23+0.21(stat)-0.13+0.12(syst)]×10-3 eV2 .

  10. Development of a Photon Detection System in Liquid Argon for the Long-Baseline Neutrino Experiment

    NASA Astrophysics Data System (ADS)

    Whittington, Denver; Adams, Brice; Baptista, Brian; Baugh, Brian; Gebhard, Mark; Lang, Michael; Mufson, Stuart; Musser, James; Smith, Paul; Urheim, Jon

    2014-03-01

    The Long-Baseline Neutrino Experiment (LBNE) will be a premier facility for exploring long-standing questions about the boundaries of the standard model. Acting in concert with the liquid argon time projection chambers underpinning the far detector design, the LBNE photon detection system will capture ultraviolet scintillation light in order to provide valuable timing information for event reconstruction. The team at Indiana University is exploring a design based on acrylic waveguides coated with a wavelength-shifting compound, combined with silicon photomultipliers, to collect and record scintillation light from liquid argon. Large-scale tests of this design are being conducted at the ``TallBo'' liquid argon dewar facility at Fermilab, where performance studies with cosmic ray events are helping steer decisions for the final detector design. We present an overview of the design and function of this photon detection system and the latest results from the analysis of data collected during these tests. Photon Detector R&D Team at Indiana University.

  11. Computer Based Simulation of Laboratory Experiments.

    ERIC Educational Resources Information Center

    Edward, Norrie S.

    1997-01-01

    Examines computer based simulations of practical laboratory experiments in engineering. Discusses the aims and achievements of lab work (cognitive, process, psychomotor, and affective); types of simulations (model building and behavioral); and the strengths and weaknesses of simulations. Describes the development of a centrifugal pump simulation,…

  12. An evaluation of water vapor radiometer data for calibration of the wet path delay in very long baseline interferometry experiments

    NASA Technical Reports Server (NTRS)

    Kuehn, C. E.; Himwich, W. E.; Clark, T. A.; Ma, C.

    1991-01-01

    The internal consistency of the baseline-length measurements derived from analysis of several independent VLBI experiments is an estimate of the measurement precision. The paper investigates whether the inclusion of water vapor radiometer (WVR) data as an absolute calibration of the propagation delay due to water vapor improves the precision of VLBI baseline-length measurements. The paper analyzes 28 International Radio Interferometric Surveying runs between June 1988 and January 1989; WVR measurements were made during each session. The addition of WVR data decreased the scatter of the length measurements of the baselines by 5-10 percent. The observed reduction in the scatter of the baseline lengths is less than what is expected from the behavior of the formal errors, which suggest that the baseline-length measurement precision should improve 10-20 percent if WVR data are included in the analysis. The discrepancy between the formal errors and the baseline-length results can be explained as the consequence of systematic errors in the dry-mapping function parameters, instrumental biases in the WVR and the barometer, or both.

  13. Experimenting With Multiprocessor Simulator Concepts

    NASA Technical Reports Server (NTRS)

    Blech, Richard A.; Williams, Anthony D.

    1989-01-01

    Multiple microcomputer system used to investigate application of parallel processing to real-time simulation. With dual-base architecture, each microcomputer communicates with corresponding microcomputer on opposite bus through dual-port interface memory. Transfers of data to and from front-end processor occur on interactive information bus. Transfers of data related to simulation calculations occur on real-time-information bus. System, called the real-time multiprocessor simulator (RTMPS), is tool for developing low-cost, portable, user-friendly simulators.

  14. Non-Baseline Damage Detection from Changes in Strain Energy Mode Shapes Experiments on Armored Vehicle Launched Bridge

    NASA Astrophysics Data System (ADS)

    Sazonov, E. S.; Klinkhachorn, P.; GangaRao, H. V. S.; Halabe, U. B.

    2003-03-01

    There are several existing methods for damage detection based on identifying changes in strain energy mode shapes. Most of these methods require knowing strain energy mode shapes for a structure without damage in order to establish a baseline for damage detection. Usually, the mode shapes from the structure under test should be compared to the baseline mode shapes to identify and locate damage. However, these methods of damage detection are not very suitable for application on structures where baseline mode shapes cannot be readily obtained, for example, structures with preexisting damage. Conventional methods, like building a finite element model of a structure to be used as a baseline might be an expensive and time-consuming task that can be impossible for complex structures. A new (non-baseline) method for the extraction of localized changes (damage peaks) from strain energy mode shapes based on Fourier analysis of the strain energy mode shapes has been developed and analytically proved for the cases of a pinned-pinned and a free-free beam. The new method looks for characteristic changes in the power spectrum of the strain energy mode shapes in order to locate and identify damage. The analytical results have been confirmed both by the finite element model and impact testing experiments on a free-free aluminum beam, including single and multiple damage scenarios. This paper presents results of testing the non-baseline method on a complex structure — Armored Vehicle Launched Bridge, which consists of loosely coupled hinged beams with variable cross-section. The results of testing confirm applicability of the non-baseline method to damage detection in complex structures and highlight certain particularities of its use.

  15. Investigation on aerodynamic characteristics of baseline-II E-2 blended wing-body aircraft with canard via computational simulation

    NASA Astrophysics Data System (ADS)

    Nasir, Rizal E. M.; Ali, Zurriati; Kuntjoro, Wahyu; Wisnoe, Wirachman

    2012-06-01

    Previous wind tunnel test has proven the improved aerodynamic charasteristics of Baseline-II E-2 Blended Wing-Body (BWB) aircraft studied in Universiti Teknologi Mara. The E-2 is a version of Baseline-II BWB with modified outer wing and larger canard, solely-designed to gain favourable longitudinal static stability during flight. This paper highlights some results from current investigation on the said aircraft via computational fluid dynamics simulation as a mean to validate the wind tunnel test results. The simulation is conducted based on standard one-equation turbulence, Spalart-Allmaras model with polyhedral mesh. The ambience of the flight simulation is made based on similar ambience of wind tunnel test. The simulation shows lift, drag and moment results to be near the values found in wind tunnel test but only within angles of attack where the lift change is linear. Beyond the linear region, clear differences between computational simulation and wind tunnel test results are observed. It is recommended that different type of mathematical model be used to simulate flight conditions beyond linear lift region.

  16. Ion exchange - Simulation and experiment

    NASA Technical Reports Server (NTRS)

    Herrmann, Cal C.; Finn, John E.

    1991-01-01

    A FORTRAN program for simulating multicomponent adsorption by ion-exchange resins was adapted for use as both an ASPEN-callable module and as a free-standing simulator of the ion-exchange bed. Four polystyrene-divinylbenzene sulfonic acid resins have been characterized for three principal ions. It is concluded that a chelating resin appears appropriate as a heavy-metal trap. The same ASPEN-callable module is used to model this resin when Wilson parameters can be obtained.

  17. Using Syllable-Timed Speech to Treat Preschool Children Who Stutter: A Multiple Baseline Experiment

    ERIC Educational Resources Information Center

    Trajkovski, Natasha; Andrews, Cheryl; Onslow, Mark; Packman, Ann; O'Brian, Sue; Menzies, Ross

    2009-01-01

    This report presents the results of an experimental investigation of the effects of a syllable-timed speech treatment on three stuttering preschool children. Syllable-timed speech involves speaking with minimal differentiation in linguistic stress across syllables. Three children were studied in a multiple baseline across participants design, with…

  18. The Employment Experiences of Public Housing Residents: Findings from the Jobs-Plus Baseline Survey.

    ERIC Educational Resources Information Center

    Martinez, John M.

    A survey collected baseline data about public housing communities and residents just prior to the start of the Jobs-Plus program. The data were from all working-age, nondisabled heads of households in eight public housing developments in seven cities with customarily high rates of joblessness and reliance on welfare. The developments were part of…

  19. Simulation and Introductory Pharmacy Practice Experiences

    PubMed Central

    Lin, Katherine; Wadelin, Jeffrey W.; Vlasses, Peter H.

    2011-01-01

    This paper reviews the literature on the various types of simulation and their incorporation into health professions curricula, describes how simulation training is recognized in other professions, and evaluates the feasibility of integrating simulation into experiential education programs of colleges and schools of pharmacy. The Accreditation Council for Pharmacy Education (ACPE) Board of Directors develop standards and guidelines on the use of simulation as part of introductory pharmacy practice experiences within the doctor of pharmacy (PharmD) curriculum. PMID:22345728

  20. Very Long Baseline Interferometry Experiment on Giant Radio Pulses of Crab Pulsar toward Fast Radio Burst Detection

    NASA Astrophysics Data System (ADS)

    Takefuji, K.; Terasawa, T.; Kondo, T.; Mikami, R.; Takeuchi, H.; Misawa, H.; Tsuchiya, F.; Kita, H.; Sekido, M.

    2016-08-01

    We report on a very long baseline interferometry (VLBI) experiment on giant radio pulses (GPs) from the Crab pulsar in the radio 1.4–1.7 GHz range to demonstrate a VLBI technique for searching for fast radio bursts (FRBs). We carried out the experiment on 2014 July 26 using the Kashima 34 m and Usuda 64 m radio telescopes of the Japanese VLBI Network (JVN) with a baseline of about 200 km. During the approximately 1 hr observation, we could detect 35 GPs by high-time-resolution VLBI. Moreover, we determined the dispersion measure (DM) to be 56.7585 ± 0.0025 on the basis of the mean DM of the 35 GPs detected by VLBI. We confirmed that the sensitivity of a detection of GPs using our technique is superior to that of a single-dish mode detection using the same telescope.

  1. Results and Status of the T2K and NOvA long-baseline neutrino experiments

    NASA Astrophysics Data System (ADS)

    Muether, Mathew

    2016-03-01

    The discovery of neutrino oscillations and the resulting implication that neutrinos have mass, recently awarded the Nobel Prize in Physics, has bolstered a world-wide effort to exploit this effect as a handle on the properties of neutrinos. In the decades since the initial discovery of neutrino oscillations, great strides have been made in understanding the nature of these elusive particles, yet important and fundamental questions remain open, such as: How are the neutrino masses ordered? And Do neutrinos and antineutrinos oscillate differently? The current generation of accelerator based long-baseline neutrino oscillation experiments, T2K in Japan and NOvA in the United States, are actively pursuing the answers to these questions. In this talk, I will review the recent results and current status of the T2K and NOvA long-baseline neutrino experiments.

  2. Decision Making in Computer-Simulated Experiments.

    ERIC Educational Resources Information Center

    Suits, J. P.; Lagowski, J. J.

    A set of interactive, computer-simulated experiments was designed to respond to the large range of individual differences in aptitude and reasoning ability generally exhibited by students enrolled in first-semester general chemistry. These experiments give students direct experience in the type of decision making needed in an experimental setting.…

  3. Simulator experiments: effects of NPP operator experience on performance

    SciTech Connect

    Beare, A.N.; Gray, L.H.

    1984-01-01

    During the FY83 research, a simulator experiment was conducted at the control room simulator for a GE Boiling Water Reactor (BWR) NPP. The research subjects were licensed operators undergoing requalification training and shift technical advisors (STAs). This experiment was designed to investigate the effects of senior reactor operator (SRO) experience, operating crew augmentation with an STA and practice, as a crew, upon crew and individual operator performance, in response to anticipated plant transients. Sixteen two-man crews of licensed operators were employed in a 2 x 2 factorial design. The SROs leading the crews were split into high and low experience groups on the basis of their years of experience as an SRO. One half of the high- and low-SRO experience groups were assisted by an STA. The crews responded to four simulated plant casualties. A five-variable set of content-referenced performance measures was derived from task analyses of the procedurally correct responses to the four casualties. System parameters and control manipulations were recorded by the computer controlling the simulator. Data on communications and procedure use were obtained from analysis of videotapes of the exercises. Questionnaires were used to collect subject biographical information and data on subjective workload during each simulated casualty. For four of the five performance measures, no significant differences were found between groups led by high (25 to 114 months) and low (1 to 17 months as an SRO) experience SROs. However, crews led by low experience SROs tended to have significantly shorter task performance times than crews led by high experience SROs. The presence of the STA had no significant effect on overall team performance in responding to the four simulated casualties. The FY84 experiments are a partial replication and extension of the FY83 experiment, but with PWR operators and simulator.

  4. Los Alamos beam halo experiment: comparing theory, simulation and experiment.

    SciTech Connect

    Wangler, Thomas P.,; Qiang, J.

    2002-01-01

    We compare macroparticle simulations with measurements from a proton beam-halo experiment in a 52-quadrupole periodic-focusing channel. Three different initial distributions with the same Courant-Snyder parameters and emittances, but different shapes, predict different beam profiles in the transport system. Input distributions with greater population in the tails produce larger rates of emittance growth, a result that is qualitatively consistent with the particle-core model of halo formation in mismatched beams. The simulations underestimate the growth rate of halo and emittance for mismatched beams. Better agreement between simulations and experiment may require an input distribution that represents more accurately the tails of the real input beam.

  5. Experience from geodetic very long baseline interferometry observations at Onsala using a digital backend

    NASA Astrophysics Data System (ADS)

    Kareinen, N.; Haas, R.

    2015-04-01

    The Onsala Space Observatory has installed a modern digital backend for geodetic and astronomical Very Long Baseline Interferometry (VLBI). This system consists of a Digital Base-Band Converter (DBBC) and a Mark 5B+ recorder. From 2011 until late 2014 this new system was run for geodetic VLBI observations in parallel with the old system consisting of a Mark 4 rack and Mark 5A recording system. Several of these observed sessions were correlated at the correlator in Bonn including both data sets. We present results from the analysis and comparison of these sessions. Both the original observed delays and corresponding geodetic parameters are compared. No significant differences are detected, for either the raw observations or for the geodetic parameters. This shows that the digital backend can be used operationally for geodetic VLBI observations.

  6. MCNP simulations of material exposure experiments (u)

    SciTech Connect

    Temple, Brian A

    2010-12-08

    Simulations of proposed material exposure experiments were performed using MCNP6. The experiments will expose ampules containing different materials of interest with radiation to observe the chemical breakdown of the materials. Simulations were performed to map out dose in materials as a function of distance from the source, dose variation between materials, dose variation due to ampule orientation, and dose variation due to different source energy. This write up is an overview of the simulations and will provide guidance on how to use the data in the spreadsheet.

  7. Neutrino Scattering Uncertainties and their Role in Long Baseline Oscillation Experiments

    SciTech Connect

    D.A. Harris; G. Blazey; Arie Bodek; D. Boehnlein; S. Boyd; William Brooks; Antje Bruell; Howard S. Budd; R. Burnstein; D. Casper; A. Chakravorty; Michael Christy; Jesse Chvojka; M.A.C. Cummings; P. deBarbaro; D. Drakoulakos; J. Dunmore; Rolf Ent; Hugh Gallagher; David Gaskell; Ronald Gilman; Charles Glashausser; Wendy Hinton; Xiaodong Jiang; T. Kafka; O. Kamaev; Cynthia Keppel; M. Kostin; Sergey Kulagin; Gerfried Kumbartzki; Steven Manly; W.A. Mann; Kevin Mcfarland-porter; Wolodymyr Melnitchouk; Jorge Morfin; D. Naples; John Nelson; Gabriel Niculescu; Maria-ioana Niculescu; W. Oliver; Michael Paolone; Emmanuel Paschos; A. Pla-Dalmau; Ronald Ransome; C. Regis; P. Rubinov; V. Rykalin; Willis Sakumoto; P. Shanahan; N. Solomey; P. Spentzouris; P. Stamoulis; G. Tzanakos; Stephen Wood; F.X. Yumiceva; B. Ziemer; M. Zois

    2004-10-01

    The field of oscillation physics is about to make an enormous leap forward in statistical precision: first through the MINOS experiment in the coming year, and later through the NOvA and T2K experiments. Because of the relatively poor understanding of neutrino interactions in the energy ranges of these experiments, there are systematics that can arise in interpreting far detector data that can be as large as or even larger than the expected statistical uncertainties. We describe how these systematic errors arise, and how specific measurements in a dedicated neutrino scattering experiment like MINERvA can reduce the cross section systematic errors to well below the statistical errors.

  8. Observing System Simulation Experiments: An Overview

    NASA Technical Reports Server (NTRS)

    Prive, Nikki C.; Errico, Ronald M.

    2016-01-01

    An overview of Observing System Simulation Experiments (OSSEs) will be given, with focus on calibration and validation of OSSE frameworks. Pitfalls and practice will be discussed, including observation error characteristics, incestuousness, and experimental design. The potential use of OSSEs for investigation of the behaviour of data assimilation systems will be explored, including some results from experiments using the NASAGMAO OSSE.

  9. Simulation of integrated beam experiment designs

    SciTech Connect

    Grote, D.P.; Sharp, W.M.

    2004-06-11

    Simulation of designs of an Integrated Beam Experiment (IBX) class accelerator have been carried out. These simulations are an important tool for validating such designs. Issues such as envelope mismatch and emittance growth can be examined in a self-consistent manner, including the details of injection, accelerator transitions, long-term transport, and longitudinal compression. The simulations are three-dimensional and time-dependent, and begin at the source. They continue up through the end of the acceleration region, at which point the data is passed on to a separate simulation of the drift compression. Results are be presented.

  10. Applicability of second-order expansion in s13 to explore δCP in small and medium baseline ν experiments

    NASA Astrophysics Data System (ADS)

    Singh, Mandip

    2016-03-01

    The series expansion of neutrino evolution matrix “S”, up to first-order in small reactor mixing angle θ13 is very useful formalism to study experiments quantitatively. The formalism has been used especially to investigate CP-violating phase δCP. In order to perform a broad investigation for the possible measurement of δCP phase, we will study small baseline experiments: Chooz (L = 1.03Km), T2K (L = 295Km) and ESS (L = 500Km), medium baseline experiment: NOνA (L = 810Km) and long baseline experiment: LBNE (L = 1300Km).

  11. Evaluation of Computer Simulated Baseline Statistics for Use in Item Bias Studies. [Revised].

    ERIC Educational Resources Information Center

    Rogers, H. Jane; Hambleton, Ronald K.

    Although item bias statistics are widely recommended for use in test development and test analysis work, problems arise in their interpretation. The purpose of the present research was to evaluate the validity of logistic test models and computer simulation methods for providing a frame of reference for item bias statistic interpretations.…

  12. Pyro shock simulation: Experience with the MIPS simulator

    NASA Technical Reports Server (NTRS)

    Dwyer, Thomas J.; Moul, David S.

    1988-01-01

    The Mechanical Impulse Pyro Shock (MIPS) Simulator at GE Astro Space Division is one version of a design that is in limited use throughout the aerospace industry, and is typically used for component shock testing at levels up to 10,000 response g's. Modifications to the force imput, table and component boundary conditions have allowed a range of test conditions to be achieved. Twelve different designs of components with weights up to 23 Kg are in the process or have completed qualification testing in the Dynamic Simulation Lab at GE in Valley Forge, Pa. A summary of the experience gained through the use of this simulator is presented as well as examples of shock experiments that can be readily simulated at the GE Astro MIPS facility.

  13. Functional endemism: population connectivity, shifting baselines, and the scale of human experience.

    PubMed

    Drew, Joshua; Kaufman, Les

    2013-02-01

    Quantifying population connectivity is important for visualizing the spatial and temporal scales that conservation measures act upon. Traditionally, migration based on genetic data has been reported in migrants per generation. However, the temporal scales over which this migration may occur do not necessarily accommodate the scales over which human perturbations occur, leaving the potential for a disconnect between population genetic data and conservation action based on those data. Here, we present a new metric called the "Rule of Memory", which helps conservation practitioners to interpret "migrants per generation" in the context both of human modified ecosystems and the cultural memory of those doing the modification. Our rule states that clades should be considered functionally endemic regardless of their actual taxonomic designation if the migration between locations is insufficient to maintain a viable population over the timescales of one human generation (20 years). Since larger animals are more likely to be remembered, we quantify the relationship between migrants per human (N) and body mass of the organism in question (M) with the formula N = 10M(-1). We then use the coral reef fish Pomacentrus moluccensis to demonstrate the taxonomic and spatial scales over which this rule can be applied. Going beyond minimum viable population literature, this metric assesses the probability that a clade's existence will be forgotten by people throughout its range during a period of extirpation. Because conservation plans are predicated on having well-established baselines, a loss of a species over the range of one human generation evokes the likelihood of that species no longer being recognized as a member of an ecosystem, and thus being excluded in restoration or conservation prioritization. [Correction added on 26 December 2012, after first online publication: this formula has been corrected to N=10M(-1)]. PMID:23467269

  14. Functional endemism: population connectivity, shifting baselines, and the scale of human experience

    PubMed Central

    Drew, Joshua; Kaufman, Les

    2013-01-01

    Quantifying population connectivity is important for visualizing the spatial and temporal scales that conservation measures act upon. Traditionally, migration based on genetic data has been reported in migrants per generation. However, the temporal scales over which this migration may occur do not necessarily accommodate the scales over which human perturbations occur, leaving the potential for a disconnect between population genetic data and conservation action based on those data. Here, we present a new metric called the “Rule of Memory”, which helps conservation practitioners to interpret “migrants per generation” in the context both of human modified ecosystems and the cultural memory of those doing the modification. Our rule states that clades should be considered functionally endemic regardless of their actual taxonomic designation if the migration between locations is insufficient to maintain a viable population over the timescales of one human generation (20 years). Since larger animals are more likely to be remembered, we quantify the relationship between migrants per human (N) and body mass of the organism in question (M) with the formula N = 10M−1. We then use the coral reef fish Pomacentrus moluccensis to demonstrate the taxonomic and spatial scales over which this rule can be applied. Going beyond minimum viable population literature, this metric assesses the probability that a clade's existence will be forgotten by people throughout its range during a period of extirpation. Because conservation plans are predicated on having well-established baselines, a loss of a species over the range of one human generation evokes the likelihood of that species no longer being recognized as a member of an ecosystem, and thus being excluded in restoration or conservation prioritization. [Correction added on 26 December 2012, after first online publication: this formula has been corrected to N=10M−1]. PMID:23467269

  15. Search for sterile neutrino mixing in the MINOS long baseline experiment

    SciTech Connect

    Adamson, P.; Andreopoulos, C.; Auty, D.J.; Ayres, D.S.; Backhouse, C.; Barnes Jr., P.D.; Barr, G.; Barrett, W.L.; Bishai, M.; Blake, A.; Bock, G.J.; /Fermilab /Fermilab

    2010-01-01

    A search for depletion of the combined flux of active neutrino species over a 735 km baseline is reported using neutral-current interaction data recorded by the MINOS detectors in the NuMI neutrino beam. Such a depletion is not expected according to conventional interpretations of neutrino oscillation data involving the three known neutrino flavors. A depletion would be a signature of oscillations or decay to postulated noninteracting sterile neutrinos, scenarios not ruled out by existing data. From an exposure of 3.18 x 10{sup 20} protons on target in which neutrinos of energies between {approx}500 MeV and 120 GeV are produced predominantly as {nu}{sub {mu}}, the visible energy spectrum of candidate neutral-current reactions in the MINOS far-detector is reconstructed. Comparison of this spectrum to that inferred from a similarly selected near-detector sample shows that of the portion of the {nu}{sub {mu}} flux observed to disappear in charged-current interaction data, the fraction that could be converting to a sterile state is less than 52% at 90% confidence level (C.L.). The hypothesis that active neutrinos mix with a single sterile neutrino via oscillations is tested by fitting the data to various models. In the particular four-neutrino models considered, the mixing angles {theta}{sub 24} and {theta}{sub 34} are constrained to be less than 11{sup o} and 56{sup o} at 90% C.L., respectively. The possibility that active neutrinos may decay to sterile neutrinos is also investigated. Pure neutrino decay without oscillations is ruled out at 5.4 standard deviations. For the scenario in which active neutrinos decay into sterile states concurrently with neutrino oscillations, a lower limit is established for the neutrino decay lifetime {tau}{sub 3}/m{sub 3} > 2.1 x 10{sup -12} s/eV at 90% C.L.

  16. Photographic Emulsions in the OPERA Long Baseline Experiment Status and First Results

    NASA Astrophysics Data System (ADS)

    Meisel, Frank W.

    2010-04-01

    The OPERA experiment (Oscillation Project with Emulsion tRacking Apparatus) has been designed to confirm the neutrino oscillation hypothesis by direct observation of the tau neutrino appearance coming out of a (almost) pure muon neutrino beam. The beam is extracted from the SPS at CERN towards the Gran Sasso Underground Laboratory, the location of OPERA, 730km afar. In order to detect the leptonic tau decays, the vertex detector needs a spatial resolution of the order of micrometers. Nuclear emulsion films are the only detector materials capable of fulfilling this tight condition. In addition, emulsion scanning techniques have been significantly improved during the last recent neutrino experiments. This article is going to review the status of the detector, the neutrino beam properties, the first results from the 2008 run and the neutrino event analyses putting special emphasis on the emulsion detection technique.

  17. Simulation Experiments with Cometary Analogous Material

    NASA Astrophysics Data System (ADS)

    Kochan, Hermann W.; Huebner, Walter F.; Sears, Derek W. G.

    1998-12-01

    Comet simulation experiments are discussed, in the context of physical models and the results in cometary physics, gathered especially from the GIOTTO space mission to comet P'Halley. The “status of the today knowledge” about comets, the experiments could start from, is briefly reviewed. The setup of the KOSI (German = Kometen Simulation) - experiments and the techniques to produce cometary analogous material, on the basis of that knowledge are described in general, as for the different KOSI experiments. The limitations of the simulation of physical processes at the surface of real comets in an earth-bound laboratory are discussed, and the possibilities to receive common insights in cometary physics are shown. Methods and procedures are described, and the major results reviewed. As with attempting to reproduce any natural phenomenon in the laboratory, there are short-comings to these experiments, but there are possibly major new insights to be gained. Physical laws only have the same consequences under same experimental or environmental conditions. A number of small-scale comet simulation experiments have been performed, since the early 60ties in many laboratories, but the largest and most ambitious series of comet simulation experiments to date were performed between 1987 and 1993 using the German space agency's (DLR) space hardware testing facilities in Cologne. These experiments were triggered by the scientific community after the comet P'Halley's recurrence in 1986 and the many data gathered by the space missions in this year. Simulation experiments have proved valuable in developing methods for making cometary analogues, and for exploring specific properties of such materials in detail. These experiments provided new insights into the morphology and physical behavior of aggregates formed out of silicate- /water-ice -grains likely to exist in comets. The formation of a dust mantle on the surface, and a system of ice layers below the mantle from the

  18. Simulations of DT experiments in TFTR

    SciTech Connect

    Budny, R.; Bell, M.G.; Biglari, H.; Bitter, M.; Bush, C.; Cheng, C.Z.; Fredrickson, E.; Grek, B.; Hill, K.W.; Hsuan, H.; Janos, A.; Jassby, D.L.; Johnson, D.; Johnson, L.C.; LeBlanc, B.; McCune, D.C.; Mikkelsen, D.R.; Park, H.; Ramsey, A.T.; Sabbagh, S.A.; Scott, S.; Schivell, J.; Strachan, J.D.; Stratton, B.C.; Synakowski, E.; Taylor, G.; Zarnstorff, M.C.; Zweben, S.J.

    1991-12-01

    A transport code (TRANSP) is used to simulate future deuterium-tritium experiments (DT) in TFTR. The simulations are derived from 14 TFTR DD discharges, and the modeling of one supershot is discussed in detail to indicate the degree of accuracy of the TRANSP modeling. Fusion energy yields and {alpha}-particle parameters are calculated, including profiles of the {alpha} slowing down time, average energy, and of the Alfven speed and frequency. Two types of simulations are discussed. The main emphasis is on the DT equivalent, where an equal mix of D and T is substituted for the D in the initial target plasma, and for the D{sup O} in the neutral-beam injection, but the other measured beam and plasma parameters are unchanged. This simulation does not assume that {alpha} heating will enhance the plasma parameters, or that confinement will increase with T. The maximum relative fusion yield calculated for these simulations is Q{sub DT} {approx} 0.3, and the maximum {alpha} contribution to the central toroidal {beta} is {beta}{sub {alpha}}(0) {approx} 0.5%. The stability of toroidicity-induced Alfven eigenmodes (TAE) and kinetic ballooning modes (KBM) is discussed. The TAE mode is predicted to become unstable for some of the equivalent simulations, particularly after the termination of neutral beam injection. In the second type of simulation, empirical supershot scaling relations are used to project the performance at the maximum expected beam power. The MHD stability of the simulations is discussed.

  19. Psychology on Computers: Simulations, Experiments and Projects.

    ERIC Educational Resources Information Center

    Belcher, Duane M.; Smith, Stephen D.

    PSYCOM is a unique mixed media package which combines high interest projects on the computer with a written text of expository material. It goes beyond most computer-assisted instruction which emphasizes drill and practice and testing of knowledge. A project might consist of a simulation or an actual experiment, or it might be a demonstration, a…

  20. Design and Simulation of Hybridization Experiments

    Energy Science and Technology Software Center (ESTSC)

    1995-11-28

    DB EXP DESIGN is a suite of three UNIX shell-like programs, DWC which computes oligomer composition of DNA texts using directed acyclic word data structures; DWO, which simulates hybridization experiments; and DMI, which calculates the information contenet of individual probes, their mutual information content, and their joint information content through estimation of Markov trees.

  1. GEANT4 Simulation of the NPDGamma Experiment

    NASA Astrophysics Data System (ADS)

    Frlez, Emil

    2014-03-01

    The n-> + p --> d + γ experiment, currently taking data at the Oak Ridge SNS facility, is a high-precision measurement of weak nuclear forces at low energies. Detecting the correlation between the cold neutron spin and photon direction in the capture of neutrons on Liquid Hydrogen (LH) target, the experiment is sensitive to the properties of neutral weak current. We have written a GEANT4 Monte Carlo simulation of the NPDGamma detector that, in addition to the active CsI detectors, also includes different targets and passive materials as well as the beam line elements. The neutron beam energy spectrum, its profiles, divergencies, and time-of-flight are simulated in detail. We have used the code to cross-calibrate the positions of (i) polarized LH target, (ii) Aluminum target, and (iii) CCl4 target. The responses of the 48 CsI detectors in the simulation were fixed using data taken on the LH target. Both neutron absorption as well as scattering and thermal processes were turned on in the GEANT4 physics lists. We use the results to simulate in detail the data obtained with different targets used in the experiment within a comprehensive analysis. This work is supported by NSF grant PHY-1307328.

  2. Neutron Tracking Simulations for the UCNτ experiment

    NASA Astrophysics Data System (ADS)

    Adamek, Evan

    2012-10-01

    The UCNτ experiment aims to measure the neutron beta-decay lifetime to 1 s total uncertainty and beyond by trapping ultracold neutrons (UCN) in a gravito-magnetic trap, in which UCN will undergo no material wall interactions. To study the feasibility in this experimental technique, we have built Monte-Carlo simulations of the full-scale UCNτ experiment. The simulation program consists of two major components: one focuses on simulation of the UCN flux in the guide tubes, and the other on UCN tracking inside the trap. The first simulation studies optimized delivery of UCN into the trap and evaluates the effectiveness of relative flux monitoring to infer the number of trappable UCN for each fill. The second simulation tracks UCN, originating from the trap door, over the entire accessible region. Symplectic integrators are used to integrate the equations of motion of UCN using the full potential. Focus is given to studying the phase-space evolution of marginally trapped UCN. These neutrons have a large tangential velocity component and could be leaking out of the trap slowly (due to non-harmonic components in the trapping potential) and thus skewing the accuracy of the neutron beta-decay lifetime. In this talk, we will discuss many of these subtle effects.

  3. Titan's organic chemistry: Results of simulation experiments

    NASA Technical Reports Server (NTRS)

    Sagan, Carl; Thompson, W. Reid; Khare, Bishun N.

    1992-01-01

    Recent low pressure continuous low plasma discharge simulations of the auroral electron driven organic chemistry in Titan's mesosphere are reviewed. These simulations yielded results in good accord with Voyager observations of gas phase organic species. Optical constants of the brownish solid tholins produced in similar experiments are in good accord with Voyager observations of the Titan haze. Titan tholins are rich in prebiotic organic constituents; the Huygens entry probe may shed light on some of the processes that led to the origin of life on Earth.

  4. Pulse shape discrimination capability of metal-loaded organic liquid scintillators for a short-baseline reactor neutrino experiment

    NASA Astrophysics Data System (ADS)

    Kim, B. R.; Han, B. Y.; Jeon, E. J.; Joo, K. K.; Kang, Jeongsoo; Khan, N.; Kim, H. J.; Kim, Hyunsoo; Kim, J. Y.; Siyeon, Kim; Kim, S. C.; Kim, Yeongduk; Ko, Y. J.; Lee, Jaison; Lee, Jeong-Yeon; Lee, J. Y.; Ma, K. J.; Park, Hyeonseo; Park, H. K.; Park, K. S.; Seo, K. M.; Seon, Gwang-Min; Yeo, I. S.; Yeo, K. M.

    2015-05-01

    A new short-baseline (SBL) reactor neutrino experiment is proposed to investigate a reactor anti-neutrino anomaly. A liquid scintillator (LS) is used to detect anti-neutrinos emitted from a Hanaro reactor, and the pulse shape discrimination (PSD) ability of the metal-loaded organic LSs is evaluated on small-scale laboratory samples. PSD can be affected by selecting different base solvents, and several of the LSs used two different organic base solvents, such as linear alkyl benzene and di-isopropylnaphthalene. For the metallic content, gadolinium (Gd) or lithium (6Li) was loaded into a home-made organic LS and into a commercially available liquid scintillation cocktail. A feasibility study was performed for the PSD using several different liquid scintillation cocktails. In this work, the preparation and the PSD characteristics of a promising candidate, which will be used in an above-ground environment, are summarized and presented.

  5. Simulated experiences: nursing students share their perspectives.

    PubMed

    Baxter, Pamela; Akhtar-Danesh, Noori; Valaitis, Ruta; Stanyon, Wendy; Sproul, Susan

    2009-11-01

    In an attempt to address a shortage of clinical nursing placements, the rising complexity of care and to increase preparedness of students entering clinical settings, the provincial government of Ontario invested significant funding for the purchase of simulation equipment in undergraduate Schools of Nursing. What students believe about simulation and learning can influence how it is used and can also provide faculty with a better understanding of how it can best be implemented. This study explored nursing students' viewpoints about the use of simulation in their nursing programs. Q-methodology was the research approach used. In total, 24 students from 17 universities and colleges participated in the study. Although all students felt that simulated experiences could support learning overall, four groups of students were identified who had differing viewpoints. Described as reflectors, reality skeptics, comfort seekers, and technology savvies, these four groups of students require unique approaches to better engage them in learning with simulation. This study provides recommendations for faculty to consider, taking into account these varied viewpoints regarding simulation in nursing education. PMID:19500886

  6. Kinetic simulation of a plasma collision experiment

    SciTech Connect

    Larroche, O. )

    1993-08-01

    The ionic Fokker--Planck code which was written for describing plasma shock wave fronts [M. Casanova [ital et] [ital al]. Phys. Rev. Lett. [bold 67], 2143 (1991)] is applied to model the collision of two plasmas in plane geometry. Improvements brought to the code for that purpose are described. The initial phase of the experiment during which the plasmas interpenetrate is accounted for by a simple fluid model, which yields qualitative insight into the phenomena at play as well as an initial condition to start the kinetic simulation. The kinetic results obtained in the stagnation and thermalization phases are discussed with respect to a specific laser-produced plasma collision experiment, as well as to existing fluid and kinetic ( particle-in-cell'') simulations.

  7. Kinetic simulation of a plasma collision experiment

    NASA Astrophysics Data System (ADS)

    Larroche, Olivier

    1993-08-01

    The ionic Fokker-Planck code which was written for describing plasma shock wave fronts [M. Casanova et al. Phys. Rev. Lett. 67, 2143 (1991)] is applied to model the collision of two plasmas in plane geometry. Improvements brought to the code for that purpose are described. The initial phase of the experiment during which the plasmas interpenetrate is accounted for by a simple fluid model, which yields qualitative insight into the phenomena at play as well as an initial condition to start the kinetic simulation. The kinetic results obtained in the stagnation and thermalization phases are discussed with respect to a specific laser-produced plasma collision experiment, as well as to existing fluid and kinetic (``particle-in-cell'') simulations.

  8. Observing System Simulation Experiments for air quality

    NASA Astrophysics Data System (ADS)

    Timmermans, R. M. A.; Lahoz, W. A.; Attié, J.-L.; Peuch, V.-H.; Curier, R. L.; Edwards, D. P.; Eskes, H. J.; Builtjes, P. J. H.

    2015-08-01

    This review paper provides a framework for the application of the Observing System Simulation Experiment (OSSE) methodology to satellite observations of atmospheric constituents relevant for air quality. The OSSEs are experiments used to determine the potential benefit of future observing systems using an existing monitoring or forecasting system and by this can help to define optimal characteristics of future instruments. To this end observations from future instruments are simulated from a model representing the realistic state of the atmosphere and an instrument simulator. The added value of the new observations is evaluated through assimilation into another model or model version and comparison with the simulated true state and a control run. This paper provides an overview of existing air quality OSSEs focusing on ozone, CO and aerosol. Using illustrative examples from these studies we present the main elements of an air quality OSSE and associated requirements based on evaluation of the existing studies and experience within the meteorological community. The air quality OSSEs performed hitherto provide evidence of their usefulness for evaluation of future observations although most studies published do not meet all the identified requirements. Especially the evaluation of the OSSE set-up requires more attention; the differences between the assimilation model and the simulated truth should approximate differences between models and real observations. Although this evaluation is missing in many studies, it is required to ensure realistic results. Properly executed air quality OSSEs are a valuable and cost effective tool to space agencies and instrument builders when applied at the start of the development stage to ensure future observations provide added value to users of Earth Observation data.

  9. Polar-direct-drive simulations and experiments

    SciTech Connect

    Marozas, J.A.; Marshall, F.J.; Craxton, R.S.; Igumenshchev, I.V.; Skupsky, S.; Bonino, M.J.; Collins, T.J.B.; Epstein, R.; Glebov, V.Yu.; Jacobs-Perkins, D.; Knauer, J.P.; McCrory, R.L.; McKenty, P.W.; Meyerhofer, D.D.; Noyes, S.G.; Radha, P.B.; Sangster, T.C.; Seka, W.; Smalyuk, V.A.

    2006-05-15

    Polar direct drive (PDD) [S. Skupsky et al., Phys. Plasmas 11, 2763 (2004)] will allow direct-drive ignition experiments on the National Ignition Facility (NIF) [J. Paisner et al., Laser Focus World 30, 75 (1994)] as it is configured for x-ray drive. Optimal drive uniformity is obtained via a combination of beam repointing, pulse shapes, spot shapes, and/or target design. This article describes progress in the development of standard and 'Saturn' [R. S. Craxton and D. W. Jacobs-Perkins, Phys. Rev. Lett. 94, 0952002 (2005)] PDD target designs. Initial evaluation of experiments on the OMEGA Laser System [T. R. Boehly et al., Rev. Sci. Instrum. 66, 508 (1995)] and simulations were carried out with the two-dimensional hydrodynamics code SAGE [R. S. Craxton et al., Phys. Plasmas 12, 056304 (2005)]. This article adds to this body of work by including fusion particle production and transport as well as radiation transport within the two-dimensional DRACO [P. B. Radha et al., Phys. Plasmas 12, 032702 (2005)] hydrodynamics simulations used to model experiments. Forty OMEGA beams arranged in six rings to emulate the NIF x-ray-drive configuration are used to perform direct-drive implosions of CH shells filled with D{sub 2} gas. Target performance was diagnosed with framed x-ray backlighting and by the measured fusion yield. Saturn target experiments have resulted in {approx}75% of the yield from energy-equivalent, symmetrically irradiated implosions. The results of the two-dimensional PDD simulations performed with DRACO are in good agreement with experimental x-ray radiographs. DRACO is being used to further optimize standard PDD designs. In addition, DRACO simulations of NIF-scale PDD designs show ignition with a gain of 20 and the development of a 40 {mu}m radius, 10 keV region with a neutron-averaged {rho}r of 1270 mg/cm{sup 2} near stagnation.

  10. Collaborative virtual experience based on reconfigurable simulation

    NASA Astrophysics Data System (ADS)

    Shahab, Qonita M.; Kwon, Yong-Moo; Ko, Heedong

    2006-10-01

    Virtual Reality simulation enables immersive 3D experience of a Virtual Environment. A simulation-based Virtual Environment can be used to map real world phenomena onto virtual experience. With a reconfigurable simulation, users can reconfigure the parameters of the involved objects, so that they can see different effects from the different configurations. This concept is suitable for a classroom learning of physics law. This research studies the Virtual Reality simulation of Newton's physics law on rigid body type of objects. With network support, collaborative interaction is enabled so that people from different places can interact with the same set of objects in immersive Collaborative Virtual Environment. The taxonomy of the interaction in different levels of collaboration is described as: distinct objects and same object, in which there are same object - sequentially, same object - concurrently - same attribute, and same object - concurrently - distinct attributes. The case studies are the interaction of users in two cases: destroying and creating a set of arranged rigid bodies. In Virtual Domino, users can observe physics law while applying force to the domino blocks in order to destroy the arrangements. In Virtual Dollhouse, users can observe physics law while constructing a dollhouse using existing building blocks, under gravity effects.

  11. Hydrodynamic Simulations of Gaseous Argon Shock Experiments

    NASA Astrophysics Data System (ADS)

    Garcia, Daniel; Dattelbaum, Dana; Goodwin, Peter; Morris, John; Sheffield, Stephen; Burkett, Michael

    2015-06-01

    The lack of published Argon gas shock data motivated an evaluation of the Argon Equation of State (EOS) in gas phase initial density regimes never before reached. In particular, these regimes include initial pressures in the range of 200-500 psi (0.025 - 0.056 g/cc) and initial shock velocities around 0.2 cm/ μs. The objective of the numerical evaluation was to develop a physical understanding of the EOS behavior of shocked and subsequently multiply re-shocked Argon gas initially pressurized to 200-500 psi through Pagosa numerical hydrodynamic simulations utilizing the SESAME equation of state. Pagosa is a Los Alamos National Laboratory 2-D and 3-D Eulerian hydrocode capable of modeling high velocity compressible flow with multiple materials. The approach involved the use of gas gun experiments to evaluate the shock and multiple re-shock behavior of pressurized Argon gas to validate Pagosa simulations and the SESAME EOS. Additionally, the diagnostic capability within the experiments allowed for the EOS to be fully constrained with measured shock velocity, particle velocity and temperature. The simulations demonstrate excellent agreement with the experiments in the shock velocity/particle velocity space, but note unanticipated differences in the ionization front temperatures.

  12. Miller experiments in atomistic computer simulations

    PubMed Central

    Saitta, Antonino Marco; Saija, Franz

    2014-01-01

    The celebrated Miller experiments reported on the spontaneous formation of amino acids from a mixture of simple molecules reacting under an electric discharge, giving birth to the research field of prebiotic chemistry. However, the chemical reactions involved in those experiments have never been studied at the atomic level. Here we report on, to our knowledge, the first ab initio computer simulations of Miller-like experiments in the condensed phase. Our study, based on the recent method of treatment of aqueous systems under electric fields and on metadynamics analysis of chemical reactions, shows that glycine spontaneously forms from mixtures of simple molecules once an electric field is switched on and identifies formic acid and formamide as key intermediate products of the early steps of the Miller reactions, and the crucible of formation of complex biological molecules. PMID:25201948

  13. Assessing the implications of baseline climate uncertainty on simulated water yield within the Himalayan Beas river basin in NW India

    NASA Astrophysics Data System (ADS)

    Holman, I.; Remesan, R.; Adeloye, A.; Ojha, C. S.

    2013-12-01

    baseline hydrological model performance with, for example, calibration Nash-Sutcliffe Efficiencies ranging from 0.56 to 0.68 across the precipitation datasets (using CFSR data to derive evapotranspiration) for the river Beas. To evaluate the potential impact of such uncertainty on assessments of future water yield, we further describe the application of a scenario-neutral modelling framework using IPPC AR4 ranges of temperature and precipitation changes to the baseline datasets to assess the differences in their response surfaces. The results show that the uncertainty in the driving hydroclimatological variables, associated with the choice of underlying observational dataset and the choice of evopo-transpiration method, translates into significant temporal and spatial uncertainty in simulated baseline and future water yield with significant implications for our ability to project changes in the water cycle in such sensitive regions.

  14. PHITS simulations of the Matroshka experiment

    NASA Astrophysics Data System (ADS)

    Gustafsson, Katarina; Sihver, Lembit; Mancusi, Davide; Sato, Tatsuhiko

    In order to design a more secure space exploration, radiation exposure estimations are necessary; the radiation environment in space is very different from the one on Earth and it is harmful for humans and for electronic equipments. The threat origins from two sources: Galactic Cosmic Rays and Solar Particle Events. It is important to understand what happens when these particles strike matter such as space vehicle walls, human organs and electronics. We are therefore developing a tool able to estimate the radiation exposure to both humans and electronics. The tool will be based on PHITS, the Particle and Heavy-Ion Transport code System, a three dimensional Monte Carlo code which can calculate interactions and transport of particles and heavy ions in matter. PHITS is developed by a collaboration between RIST (Research Organization for Information Science & Technology), JAEA (Japan Atomic Energy Agency), KEK (High Energy Accelerator Research Organization), Japan and Chalmers University of Technology, Sweden. A method for benchmarking and developing the code is to simulate experiments performed in space or on Earth. We have carried out simulations of the Matroshka experiment which focus on determining the radiation load on astronauts inside and outside the International Space Station by using a torso of a tissue equivalent human phantom, filled with active and passive detectors located in the positions of critical tissues and organs. We will present status and results of our simulations.

  15. Computer simulations of WIGWAM underwater experiment

    SciTech Connect

    Kamegai, Minao; White, J.W.

    1993-11-01

    We performed computer simulations of the WIGWAM underwater experiment with a 2-D hydro-code, CALE. First, we calculated the bubble pulse and the signal strength at the closest gauge in one-dimensional geometry. The calculation shows excellent agreement with the measured data. Next, we made two-dimensional simulations of WIGWAM applying the gravity over-pressure, and calculated the signals at three selected gauge locations where measurements were recorded. The computed peak pressures at those gauge locations come well within the 15% experimental error bars. The signal at the farthest gauge is of the order of 200 bars. This is significant, because at this pressure the CALE output can be linked to a hydro-acoustics computer program, NPE Code (Nonlinear Progressive Wave-equation Code), to analyze the long distance propagation of acoustical signals from the underwater explosions on a global scale.

  16. 33alloy: comparison between experiment and simulation

    SciTech Connect

    Kramer, M J; Mendelev, M I; Asta, M

    2014-04-22

    We report data on the structure of liquid Al and an Al67Mg33 alloy obtained from state-of-the-art X-ray diffraction experiments and ab initio molecular dynamics (AIMD) simulations. To facilitate a direct comparison between these data, we develop a method to elongate the AIMD pair correlation function in order to obtain reliable AIMD structure factors. The comparison reveals an appreciable level of discrepancy between experimental and AIMD liquid structures, with the latter being consistently more ordered than the former at the same temperature. The discrepancy noted in this study is estimated to have significant implications for simulation-based calculations of liquid transport properties and solid–liquid interface kinetic properties.

  17. Coulomb balls in Experiment and Simulation

    SciTech Connect

    Block, D.; Arp, O.; Piel, A.; Melzer, A.

    2005-10-31

    Recently, it was shown that it is possible to confine spherical dust clouds in a plasma. It was found that these dust clouds have a crystalline structure which differs notably from the well known fcc, bcc and hcp order in extended crystalline systems. The experiments show that the particles arrange in nested shells with hexagonal order on individual shells. The high transparency and the rather slow time scales of Coulomb balls allow to observe individual particles with video microscopy techniques and therefore to determine the structural properties of Coulomb balls with high accuracy. This contribution presents a comparison of experimental results and MD-Simulations.

  18. Learning in innovation networks: Some simulation experiments

    NASA Astrophysics Data System (ADS)

    Gilbert, Nigel; Ahrweiler, Petra; Pyka, Andreas

    2007-05-01

    According to the organizational learning literature, the greatest competitive advantage a firm has is its ability to learn. In this paper, a framework for modeling learning competence in firms is presented to improve the understanding of managing innovation. Firms with different knowledge stocks attempt to improve their economic performance by engaging in radical or incremental innovation activities and through partnerships and networking with other firms. In trying to vary and/or to stabilize their knowledge stocks by organizational learning, they attempt to adapt to environmental requirements while the market strongly selects on the results. The simulation experiments show the impact of different learning activities, underlining the importance of innovation and learning.

  19. Parallel Simulation of Underdense Plasma Photocathode Experiments

    NASA Astrophysics Data System (ADS)

    Bruhwiler, David; Hidding, Bernhard; Xi, Yunfeng; Andonian, Gerard; Rosenzweig, James; Cormier-Michel, Estelle

    2013-10-01

    The underdense plasma photocathode concept (aka Trojan horse) is a promising approach to achieving fs-scale electron bunches with pC-scale charge and transverse normalized emittance below 0.01 mm-mrad, yielding peak currents of order 100 A and beam brightness as high as 1019 A /m2 / rad2 , for a wide range of achievable beam energies up to 10 GeV. A proof-of-principle experiment will be conducted at the FACET user facility in early 2014. We present 2D and 3D simulations with physical parameters relevant to the planned experiment. Work supported by DOE under Contract Nos. DE-SC0009533, DE-FG02-07ER46272 and DEFG03-92ER40693, and by ONR under Contract No. N00014-06-1-0925. NERSC computing resources are supported by DOE.

  20. ALEGRA -- code validation: Experiments and simulations

    SciTech Connect

    Chhabildas, L.C.; Konrad, C.H.; Mosher, D.A.; Reinhart, W.D; Duggins, B.D.; Rodeman, R.; Trucano, T.G.; Summers, R.M.; Peery, J.S.

    1998-03-16

    In this study, the authors are providing an experimental test bed for validating features of the ALEGRA code over a broad range of strain rates with overlapping diagnostics that encompass the multiple responses. A unique feature of the Arbitrary Lagrangian Eulerian Grid for Research Applications (ALEGRA) code is that it allows simultaneous computational treatment, within one code, of a wide range of strain-rates varying from hydrodynamic to structural conditions. This range encompasses strain rates characteristic of shock-wave propagation (10{sup 7}/s) and those characteristic of structural response (10{sup 2}/s). Most previous code validation experimental studies, however, have been restricted to simulating or investigating a single strain-rate regime. What is new and different in this investigation is that the authors have performed well-instrumented experiments which capture features relevant to both hydrodynamic and structural response in a single experiment. Aluminum was chosen for use in this study because it is a well characterized material--its EOS and constitutive material properties are well defined over a wide range of loading rates. The current experiments span strain rate regimes of over 10{sup 7}/s to less than 10{sup 2}/s in a single experiment. The input conditions are extremely well defined. Velocity interferometers are used to record the high strain-rate response, while low strain rate data were collected using strain gauges.

  1. Precision measurement of solar neutrino oscillation parameters by a long-baseline reactor neutrino experiment in Europe

    NASA Astrophysics Data System (ADS)

    Petcov, S. T.; Schwetz, T.

    2006-11-01

    We consider the determination of the solar neutrino oscillation parameters Δm212 and θ12 by studying oscillations of reactor anti-neutrinos emitted by nuclear power plants (located mainly in France) with a detector installed in the Frejus underground laboratory. The performances of a water Čerenkov detector of 147 kt fiducial mass doped with 0.1% of gadolinium (MEMPHYS-Gd) and of a 50 kt scale liquid scintillator detector (LENA) are compared. In both cases 3σ uncertainties below 3% on Δm212 and of about 20% on sin2θ12 can be obtained after one year of data taking. The gadolinium doped Super-Kamiokande detector (SK-Gd) in Japan can reach a similar precision if the SK/MEMPHYS fiducial mass ratio of 1 to 7 is compensated by a longer SK-Gd data taking time. Several years of reactor neutrino data collected by MEMPHYS-Gd or LENA would allow a determination of Δm212 and sin2θ12 with uncertainties of approximately 1% and 10% at 3σ, respectively. These accuracies are comparable to those that can be reached in the measurement of the atmospheric neutrino oscillation parameters Δm312 and sin2θ23 in long-baseline superbeam experiments.

  2. Numerical Simulations of Falling Sphere Viscometry Experiments.

    NASA Astrophysics Data System (ADS)

    O Dwyer, L.; Kellogg, L. H.; Lesher, C. E.

    2007-12-01

    The falling sphere technique based on Stokes' law is widely used to determine the viscosities of geologically relevant melts at high pressures. Stokes' law is valid when a rigid sphere falls slowly and steadily through a stationary and infinite Newtonian medium of uniform properties. High-pressure falling sphere experiments however, usually involve dropping a dense, refractory sphere through a liquid contained by a cylindrical capsule of finite size. The sphere velocity is influenced by the walls (Faxen correction) and ends of the capsule, and possible convective motion of the fluid. Efforts are made to minimize thermal gradients in laboratory experiments, but small temperature differences within the capsule can lead to convection complicating interpretation. We utilize GALE (Moresi et al., 2003;), a finite element particle-in-cell code, to examine these factors in numerical models of conditions similar to those of high-pressure experiments. Our modeling considers a three- dimensional box or cylinder containing a cluster of particles that represent the dense sphere in laboratory experiments surrounded by low viscosity particles representing the melt. GALE includes buoyancy forces, heat flow, and viscosity variations so our model can be used to assess the effects of the capsule's walls and ends, and the consequences of thermal gradients on the sphere's velocity and trajectory. Comparisons between our numerical simulations and real-time falling sphere experiments involving lower viscosity molten komatiite are made to assess the validity of Stokes' law with the standard Faxen correction included, and formulations considering end effects. The modeling also permits an evaluation of the uncertainties in recovering accurate liquid viscosities from Stokes' law when a dense sphere falls through a convecting low viscosity melt. It also allows us to assess acceleration to a terminal velocity that can provide constraints on melt viscosity in experiments in which the terminal

  3. Optical Orbit Determination of a Geosynchronous Earth Orbit Satellite Effected by Baseline Distances between Various Ground-based Tracking Stations I: COMS simulation case

    NASA Astrophysics Data System (ADS)

    Son, Ju Young; Jo, Jung Hyun; Choi, Jin

    2015-09-01

    To protect and manage the Korean space assets including satellites, it is important to have precise positions and orbit information of each space objects. While Korea currently lacks optical observatories dedicated to satellite tracking, the Korea Astronomy and Space Science Institute (KASI) is planning to establish an optical observatory for the active generation of space information. However, due to geopolitical reasons, it is difficult to acquire an adequately sufficient number of optical satellite observatories in Korea. Against this backdrop, this study examined the possible locations for such observatories, and performed simulations to determine the differences in precision of optical orbit estimation results in relation to the relative baseline distance between observatories. To simulate more realistic conditions of optical observation, white noise was introduced to generate observation data, which was then used to investigate the effects of baseline distance between optical observatories and the simulated white noise. We generated the optical observations with white noise to simulate the actual observation, estimated the orbits with several combinations of observation data from the observatories of various baseline differences, and compared the estimated orbits to check the improvement of precision. As a result, the effect of the baseline distance in combined optical GEO satellite observation is obvious but small compared to the observation resolution limit of optical GEO observation.

  4. NASCAP simulation of PIX 2 experiments

    NASA Technical Reports Server (NTRS)

    Roche, J. C.; Mandell, M. J.

    1985-01-01

    The latest version of the NASCAP/LEO digital computer code used to simulate the PIX 2 experiment is discussed. NASCAP is a finite-element code and previous versions were restricted to a single fixed mesh size. As a consequence the resolution was dictated by the largest physical dimension to be modeled. The latest version of NASCAP/LEO can subdivide selected regions. This permitted the modeling of the overall Delta launch vehicle in the primary computational grid at a coarse resolution, with subdivided regions at finer resolution being used to pick up the details of the experiment module configuration. Langmuir probe data from the flight were used to estimate the space plasma density and temperature and the Delta ground potential relative to the space plasma. This information is needed for input to NASCAP. Because of the uncertainty or variability in the values of these parameters, it was necessary to explore a range around the nominal value in order to determine the variation in current collection. The flight data from PIX 2 were also compared with the results of the NASCAP simulation.

  5. Observation simulation experiments with regional prediction models

    NASA Technical Reports Server (NTRS)

    Diak, George; Perkey, Donald J.; Kalb, Michael; Robertson, Franklin R.; Jedlovec, Gary

    1990-01-01

    Research efforts in FY 1990 included studies employing regional scale numerical models as aids in evaluating potential contributions of specific satellite observing systems (current and future) to numerical prediction. One study involves Observing System Simulation Experiments (OSSEs) which mimic operational initialization/forecast cycles but incorporate simulated Advanced Microwave Sounding Unit (AMSU) radiances as input data. The objective of this and related studies is to anticipate the potential value of data from these satellite systems, and develop applications of remotely sensed data for the benefit of short range forecasts. Techniques are also being used that rely on numerical model-based synthetic satellite radiances to interpret the information content of various types of remotely sensed image and sounding products. With this approach, evolution of simulated channel radiance image features can be directly interpreted in terms of the atmospheric dynamical processes depicted by a model. Progress is being made in a study using the internal consistency of a regional prediction model to simplify the assessment of forced diabatic heating and moisture initialization in reducing model spinup times. Techniques for model initialization are being examined, with focus on implications for potential applications of remote microwave observations, including AMSU and Special Sensor Microwave Imager (SSM/I), in shortening model spinup time for regional prediction.

  6. Chaos in plasma simulation and experiment

    SciTech Connect

    Watts, C.; Newman, D.E.; Sprott, J.C.

    1993-09-01

    We investigate the possibility that chaos and simple determinism are governing the dynamics of reversed field pinch (RFP) plasmas using data from both numerical simulations and experiment. A large repertoire of nonlinear analysis techniques is used to identify low dimensional chaos. These tools include phase portraits and Poincard sections, correlation dimension, the spectrum of Lyapunov exponents and short term predictability. In addition, nonlinear noise reduction techniques are applied to the experimental data in an attempt to extract any underlying deterministic dynamics. Two model systems are used to simulate the plasma dynamics. These are -the DEBS code, which models global RFP dynamics, and the dissipative trapped electron mode (DTEM) model, which models drift wave turbulence. Data from both simulations show strong indications of low,dimensional chaos and simple determinism. Experimental data were obtained from the Madison Symmetric Torus RFP and consist of a wide array of both global and local diagnostic signals. None of the signals shows any indication of low dimensional chaos or other simple determinism. Moreover, most of the analysis tools indicate the experimental system is very high dimensional with properties similar to noise. Nonlinear noise reduction is unsuccessful at extracting an underlying deterministic system.

  7. Physics potential of neutrino oscillation experiment with a far detector in Oki Island along the T2K baseline

    NASA Astrophysics Data System (ADS)

    Hagiwara, Kaoru; Kiwanami, Takayuki; Okamura, Naotoshi; Senda, Ken-ichi

    2013-06-01

    Oki Island is located between Japan and Korea along the Tokai-To-Kamioka (T2K) baseline. The distance from J-PARC to Oki Island is about 653km, which is twice that of the T2K experiment ( L = 295km). When the off-axis angle of the neutrino beam from J-PARC is 3 .0° (2 .0°) at Super-Kamiokande (SK), the off-axis beam (OAB) with 1 .4° (0 .6°) reaches at Oki Island. We examine physics case of placing a far detector in Oki Island during the T2K experimental period. We estimate the matter density profile along the Tokai-to-Oki baseline by using recent seismological measurements. For a detector of 100 kton fiducial volume and 2 .5 × 1021 POT (protons on target) exposure for both ν μ and {{overline{ν}}_{μ }} beams, we find that the mass hierarchy pattern can be distinguished at 3 σ level if sin2 2 θ RCT ≡ 4| U e3|2(1 - | U e3 |2) ≳ 0 .09, by observing the electron-like CCQE (Charged-Current Quasi Elastic) events. The CP phase in the Maki-Nakagawa-Sakata lepton flavor mixing matrix, δ MNS, can be constrained with ±20°. As a reference, we repeat the same analysis by placing the same detector in Korea at L = 1000 km and OAB=0 .5° (T2KK) and also by placing it at the SK site (T2K122). The Tokai-to-Kamioka-OKI (T2KO) sensitivity to the mass hierarchy is about 1 /3 (in \\varDelta χ_{min}^2 ) of T2KK, while the sensitivity to the phase δ MNS is similar between T2KO and T2KK. The T2K122 option has almost no sensitivity to the mass hierarchy, and cannot measure the CP phase except when δ MNS -90° (90°) for the normal (inverted) hierarchy.

  8. A simulation of data acquisition system for SSC experiments

    SciTech Connect

    Watase, Y.; Ikeda, H.

    1989-04-01

    A simulation on some parts of the data acquisition system was performed using a general purpose simulation language GPSS. Several results of the simulation are discussed for the data acquisition system for the SSC experiment.

  9. NDCX-II target experiments and simulations

    SciTech Connect

    Barnard, J. J.; More, R. M.; Terry, M.; Friedman, A.; Henestroza, E.; Koniges, A.; Kwan, J. W.; Ng, A.; Ni, P. A.; Liu, W.; Logan, B. G.; Startsev, E.; Yuen, A.

    2013-06-13

    The ion accelerator NDCX-II is undergoing commissioning at Lawrence Berkeley National Laboratory (LBNL). Its principal mission is to explore ion-driven High Energy Density Physics (HEDP) relevant to Inertial Fusion Energy (IFE) especially in the Warm Dense Matter (WDM) regime. We have carried out hydrodynamic simulations of beam-heated targets for parameters expected for the initial configuration of NDCX-II. For metal foils of order one micron thick (thin targets), the beam is predicted to heat the target in a timescale comparable to the hydrodynamic expansion time for experiments that infer material properties from measurements of the resulting rarefaction wave. We have also carried out hydrodynamic simulations of beam heating of metallic foam targets several tens of microns thick (thick targets) in which the ion range is shorter than the areal density of the material. In this case shock waves will form and we derive simple scaling laws for the efficiency of conversion of ion energy into kinetic energy of fluid flow. Geometries with a tamping layer may also be used to study the merging of a tamper shock with the end-of-range shock. As a result, this process can occur in tamped, direct drive IFE targets.

  10. KULL Simulations of OMEGA Radiation Flow Experiments

    NASA Astrophysics Data System (ADS)

    Kallman, J.; MacLaren, S.; Baker, K.; Brunner, T.; Lewis, K.; Zika, M.

    2013-10-01

    The problem of radiation flow in a right circular cylinder is of interest for the verification and validation of radiation codes since the flow is analytically analogous to diffusive free molecular flow in a similar geometry. Experiments were conducted on the OMEGA laser utilizing a low-density heated-cylindrical-wall target. The targets consisted of a 1.6 mm diameter gold hohlraum containing an on-axis 700 μm diameter SiO2 cylinder inside an 80 μm thick Ta2O5 aerogel tube. The FY13 targets also feature ``light-pipe'' diagnostics to measure the progression of the radiation front inside the foam. Simulations were run with the KULL multi-physics code, employing a new laser ray-tracing package. Comparisons of synthetic diagnostics derived from code results to x-ray measurements of drive temperature and heat front propagation provide a methodology to constrain simulation models. This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  11. NDCX-II target experiments and simulations

    NASA Astrophysics Data System (ADS)

    Barnard, J. J.; More, R. M.; Terry, M.; Friedman, A.; Henestroza, E.; Koniges, A.; Kwan, J. W.; Ng, A.; Ni, P. A.; Liu, W.; Logan, B. G.; Startsev, E.; Yuen, A.

    2014-01-01

    The ion accelerator NDCX-II is undergoing commissioning at Lawrence Berkeley National Laboratory (LBNL). Its principal mission is to explore ion-driven High Energy Density Physics (HEDP) relevant to Inertial Fusion Energy (IFE) especially in the Warm Dense Matter (WDM) regime. We have carried out hydrodynamic simulations of beam-heated targets for parameters expected for the initial configuration of NDCX-II. For metal foils of order one micron thick (thin targets), the beam is predicted to heat the target in a timescale comparable to the hydrodynamic expansion time for experiments that infer material properties from measurements of the resulting rarefaction wave. We have also carried out hydrodynamic simulations of beam heating of metallic foam targets several tens of microns thick (thick targets) in which the ion range is shorter than the areal density of the material. In this case shock waves will form and we derive simple scaling laws for the efficiency of conversion of ion energy into kinetic energy of fluid flow. Geometries with a tamping layer may also be used to study the merging of a tamper shock with the end-of-range shock. This process can occur in tamped, direct drive IFE targets.

  12. NDCX-II target experiments and simulations

    DOE PAGESBeta

    Barnard, J. J.; More, R. M.; Terry, M.; Friedman, A.; Henestroza, E.; Koniges, A.; Kwan, J. W.; Ng, A.; Ni, P. A.; Liu, W.; et al

    2013-06-13

    The ion accelerator NDCX-II is undergoing commissioning at Lawrence Berkeley National Laboratory (LBNL). Its principal mission is to explore ion-driven High Energy Density Physics (HEDP) relevant to Inertial Fusion Energy (IFE) especially in the Warm Dense Matter (WDM) regime. We have carried out hydrodynamic simulations of beam-heated targets for parameters expected for the initial configuration of NDCX-II. For metal foils of order one micron thick (thin targets), the beam is predicted to heat the target in a timescale comparable to the hydrodynamic expansion time for experiments that infer material properties from measurements of the resulting rarefaction wave. We have alsomore » carried out hydrodynamic simulations of beam heating of metallic foam targets several tens of microns thick (thick targets) in which the ion range is shorter than the areal density of the material. In this case shock waves will form and we derive simple scaling laws for the efficiency of conversion of ion energy into kinetic energy of fluid flow. Geometries with a tamping layer may also be used to study the merging of a tamper shock with the end-of-range shock. As a result, this process can occur in tamped, direct drive IFE targets.« less

  13. KULL Simulations of OMEGA Radiation Flow Experiments

    NASA Astrophysics Data System (ADS)

    Kallman, J.; MacLaren, S.; Baker, K.; Amala, P.; Lewis, K.; Zika, M.

    2012-10-01

    The problem of radiation flow in a right circular cylinder is of interest for the verification and validation of radiation codes, which utilize several mechanisms for determining radiation transport (diffusion, discrete ordinates, and Monte Carlo). This flow is analogous to free molecular flow in a similar geometry.footnotetextE. Garelis and T.E. Wainwright. Phys. Fluids. 16, 4 (1973) A series of experiments were conducted on the OMEGA laser in cases with a low-density heated cylindrical wall. The experiments consisted of a 1.6 mm diameter gold hohlraum containing an on-axis 700 μm diameter SiO2 cylinder contained in an 80 μm thick carbon foam tube. Five shots panning three test cases were used: the nominal geometry described above (heated wall), the carbon tube replaced with solid gold, and a gold cap placed on the laser end of the cylinder assembly to block axial radiation flow. Simulations of each experimental target type were run with the KULL radiation code, and were used to compare the different radiation transport packages in KULL by employing synthetic diagnostics to match the experimental DANTE cavity radiation temperature time history and soft x-ray images taken by a streak camera imaging the far end of the hohlraum.

  14. Magnetized plasma jets in experiment and simulation

    NASA Astrophysics Data System (ADS)

    Schrafel, Peter; Greenly, John; Gourdain, Pierre; Seyler, Charles; Blesener, Kate; Kusse, Bruce

    2013-10-01

    This research focuses on the initial ablation phase of a thing (20 micron) Al foil driven on the 1 MA-in-100 ns COBRA through a 5 mm diameter cathode in a radial configuration. In these experiments, ablated surface plasma (ASP) on the top of the foil and a strongly collimated axial plasma jet can be observed developing midway through current-rise. Our goal is to establish the relationship between the ASP and the jet. These jets are of interest for their potential relevance to astrophysical phenomena. An independently pulsed 200 μF capacitor bank with a Helmholtz coil pair allows for the imposition of a slow (150 μs) and strong (~1 T) axial magnetic field on the experiment. Application of this field eliminates significant azimuthal asymmetry in extreme ultraviolet emission of the ASP. This asymmetry is likely a current filamentation instability. Laser-backlit shadowgraphy and interferometry confirm that the jet-hollowing is correlated with the application of the axial magnetic field. Visible spectroscopic measurements show a doppler shift consistent with an azimuthal velocity in the ASP caused by the applied B-field. Computational simulations with the XMHD code PERSEUS qualitatively agree with the experimental results.

  15. Herbicide Persistence in Seawater Simulation Experiments.

    PubMed

    Mercurio, Philip; Mueller, Jochen F; Eaglesham, Geoff; Flores, Florita; Negri, Andrew P

    2015-01-01

    Herbicides are detected year-round in marine waters, including those of the World Heritage listed Great Barrier Reef (GBR). The few previous studies that have investigated herbicide persistence in seawater generally reported half-lives in the order of months, and several studies were too short to detect significant degradation. Here we investigated the persistence of eight herbicides commonly detected in the GBR or its catchments in standard OECD simulation flask experiments, but with the aim to mimic natural conditions similar to those found on the GBR (i.e., relatively low herbicide concentrations, typical temperatures, light and microbial communities). Very little degradation was recorded over the standard 60 d period (Experiment 1) so a second experiment was extended to 365 d. Half-lives of PSII herbicides ametryn, atrazine, diuron, hexazinone and tebuthiuron were consistently greater than a year, indicating high persistence. The detection of atrazine and diuron metabolites and longer persistence in mercuric chloride-treated seawater confirmed that biodegradation contributed to the breakdown of herbicides. The shortest half-life recorded was 88 d for growth-regulating herbicide 2,4-D at 31°C in the dark, while the fatty acid-inhibitor metolachlor exhibited a minimum half-life of 281 d. The presence of moderate light and elevated temperatures affected the persistence of most of the herbicides; however, the scale and direction of the differences were not predictable and were likely due to changes in microbial community composition. The persistence estimates here represent some of the first appropriate data for application in risk assessments for herbicide exposure in tropical marine systems. The long persistence of herbicides identified in the present study helps explain detection of herbicides in nearshore waters of the GBR year round. Little degradation of these herbicides would be expected during the wet season with runoff and associated flood plumes

  16. Herbicide Persistence in Seawater Simulation Experiments

    PubMed Central

    Mercurio, Philip; Mueller, Jochen F.; Eaglesham, Geoff; Flores, Florita; Negri, Andrew P.

    2015-01-01

    Herbicides are detected year-round in marine waters, including those of the World Heritage listed Great Barrier Reef (GBR). The few previous studies that have investigated herbicide persistence in seawater generally reported half-lives in the order of months, and several studies were too short to detect significant degradation. Here we investigated the persistence of eight herbicides commonly detected in the GBR or its catchments in standard OECD simulation flask experiments, but with the aim to mimic natural conditions similar to those found on the GBR (i.e., relatively low herbicide concentrations, typical temperatures, light and microbial communities). Very little degradation was recorded over the standard 60 d period (Experiment 1) so a second experiment was extended to 365 d. Half-lives of PSII herbicides ametryn, atrazine, diuron, hexazinone and tebuthiuron were consistently greater than a year, indicating high persistence. The detection of atrazine and diuron metabolites and longer persistence in mercuric chloride-treated seawater confirmed that biodegradation contributed to the breakdown of herbicides. The shortest half-life recorded was 88 d for growth-regulating herbicide 2,4-D at 31°C in the dark, while the fatty acid-inhibitor metolachlor exhibited a minimum half-life of 281 d. The presence of moderate light and elevated temperatures affected the persistence of most of the herbicides; however, the scale and direction of the differences were not predictable and were likely due to changes in microbial community composition. The persistence estimates here represent some of the first appropriate data for application in risk assessments for herbicide exposure in tropical marine systems. The long persistence of herbicides identified in the present study helps explain detection of herbicides in nearshore waters of the GBR year round. Little degradation of these herbicides would be expected during the wet season with runoff and associated flood plumes

  17. BASELINE ASSESSMENT

    EPA Science Inventory

    Resource Purpose:The Baseline Assessment is a project to collect data on environmental conditions in Indian country from existing data sources using a geographic enabling system called the Oracle Spatial Data Cartridge.
    Legislation/Enabling Authority:None
    S...

  18. Modeling active memory: Experiment, theory and simulation

    NASA Astrophysics Data System (ADS)

    Amit, Daniel J.

    2001-06-01

    Neuro-physiological experiments on cognitively performing primates are described to argue that strong evidence exists for localized, non-ergodic (stimulus specific) attractor dynamics in the cortex. The specific phenomena are delay activity distributions-enhanced spike-rate distributions resulting from training, which we associate with working memory. The anatomy of the relevant cortex region and the physiological characteristics of the participating elements (neural cells) are reviewed to provide a substrate for modeling the observed phenomena. Modeling is based on the properties of the integrate-and-fire neural element in presence of an input current of Gaussian distribution. Theory of stochastic processes provides an expression for the spike emission rate as a function of the mean and the variance of the current distribution. Mean-field theory is then based on the assumption that spike emission processes in different neurons in the network are independent, and hence the input current to a neuron is Gaussian. Consequently, the dynamics of the interacting network is reduced to the computation of the mean and the variance of the current received by a cell of a given population in terms of the constitutive parameters of the network and the emission rates of the neurons in the different populations. Within this logic we analyze the stationary states of an unstructured network, corresponding to spontaneous activity, and show that it can be stable only if locally the net input current of a neuron is inhibitory. This is then tested against simulations and it is found that agreement is excellent down to great detail. A confirmation of the independence hypothesis. On top of stable spontaneous activity, keeping all parameters fixed, training is described by (Hebbian) modification of synapses between neurons responsive to a stimulus and other neurons in the module-synapses are potentiated between two excited neurons and depressed between an excited and a quiescent neuron

  19. Recirculating planar magnetrons: simulations and experiment

    SciTech Connect

    Franzi, Matthew; Gilgenbach, Ronald; French, David; Lau, Y.Y.; Simon, David; Hoff, Brad; Luginsland, John W.

    2011-07-01

    The Recirculating Planar Magnetron (RPM) is a novel crossed-field device whose geometry is expected to reduce thermal load, enhance current yield as well as ease the geometric limitations in scaling to high RF frequencies as compared to the conventional cylindrical magnetrons. The RPM has two different adaptations: A. Axial B field and radial E field; B. Radial B field and axial E field. The preliminary configuration (A) to be used in experiments at the University of Michigan consists of two parallel planar sections which join on either end by cylindrical regions to form a concentric extruded ellipse. Similar to conventional magnetrons, a voltage across the AK gap in conjunction with an axial magnetic field provides the electrons with an ExB drift. The device is named RPM because the drifting electrons recirculate from one planar region to the other. The drifting electrons interact with the resonantly tuned slow wave structure on the anode causing spoke formation. These electron spokes drive a RF electric field in the cavities from which RF power may be extracted to Waveguides. The RPM may be designed in either a conventional configuration with the anode on the outside, for simplified extraction, or as an inverted magnetron with the anode at the inner conductor, for fast start-up. Currently, experiments at the Pulsed Power and Microwave Laboratory at the University of Michigan are in the setup and design phase. A conventional RPM with planar cavities is to be installed on the Michigan Electron Long Beam Accelerator (MELBA) and is anticipated to operate at -200kV, 0.2T with a beam current of 1-10 kA at 1GHz. The conventional RPM consists of 12 identical planar cavities, 6 on each planar side, with simulated quality factor of 20.

  20. A Simulated Interprofessional Rounding Experience in a Clinical Assessment Course

    PubMed Central

    Shrader, Sarah; McRae, Lacy; King, William M.; Kern, Donna

    2011-01-01

    Objective To implement a simulated interprofessional rounding experience using human patient simulators as a required activity for third-year pharmacy students in a clinical assessment course. Design Interprofessional student teams consisting of pharmacy, medical, and physician assistant students participated in a simulated interprofessional rounding experience in which they provided comprehensive medical care for a simulated patient in an inpatient setting. Assessment Students completed a survey instrument to assess interprofessional attitudes and satisfaction before and after participation in the simulated interprofessional rounding experience. Overall student attitudes regarding interprofessional teamwork and communication significantly improved; student satisfaction with the experience was high and students’ self-perceived clinical confidence improved after participation. The mean team clinical performance scores were 65% and 75% for each simulated interprofessional rounding experience. Conclusion Incorporating a simulated interprofessional rounding experience into a required clinical assessment course improved student attitudes regarding interprofessional teamwork and was associated with high student satisfaction. PMID:21769137

  1. The Marble Experiment: Overview and Simulations

    NASA Astrophysics Data System (ADS)

    Douglas, M. R.; Murphy, T. J.; Cobble, J. A.; Fincke, J. R.; Haines, B. M.; Hamilton, C. E.; Lee, M. N.; Oertel, J. A.; Olson, R. E.; Randolph, R. B.; Schmidt, D. W.; Shah, R. C.; Smidt, J. M.; Tregillis, I. L.

    2015-11-01

    The Marble ICF platform has recently been launched on both OMEGA and NIF with the goal to investigate the influence of heterogeneous mix on fusion burn. The unique separated reactant capsule design consists of an ``engineered'' CH capsule filled with deuterated plastic foam that contains pores or voids that are filled with tritium gas. Initially the deuterium and tritium are separated, but as the implosion proceeds, the D and T mix, producing a DT signature. The results of these experiments will be used to inform a probability density function (PDF) burn modelling approach for un-resolved cell morphology. Initial targets for platform development have consisted of either fine-pore foams or gas mixtures, with the goal to field the engineered foams in 2016. An overview of the Marble experimental campaign will be presented and simulations will be discussed. This work is supported by US DOE/NNSA, performed at LANL, operated by LANS LLC under contract DE-AC52-06NA25396.

  2. Simulation and analysis software for the NICA experiments

    NASA Astrophysics Data System (ADS)

    Gertsenberger, K.; Merts, S.; Rogachevsky, O.; Zinchenko, A.

    2016-08-01

    Software frameworks, developed for the NICA experiments are described briefly. The tools used for the physics event generation, detector simulation, particle reconstruction and visualization are considered.

  3. Development and Formative Evaluation of Computer Simulated College Chemistry Experiments.

    ERIC Educational Resources Information Center

    Cavin, Claudia S.; Cavin, E. D.

    1978-01-01

    This article describes the design, preparation, and initial evaluation of a set of computer-simulated chemistry experiments. The experiments entailed the use of an atomic emission spectroscope and a single-beam visible absorption spectrophometer. (Author/IRT)

  4. Baseline program

    NASA Technical Reports Server (NTRS)

    Roberts, Barney B.; Vonputtkamer, Jesco

    1992-01-01

    This assumed program was developed from several sources of information and is extrapolated over future decades using a set of reasonable assumptions based on incremental growth. The assumptions for the NASA baseline program are as follows: balanced emphasis in four domains; a constant level of activity; low to moderate real budget growth; maximum use of commonality; and realistic and practical technology development. The first domain is low Earth Orbit (LEO). Activities there are concentrated on the space station but extend on one side to Earth-pointing sensors for unmanned platforms and on the other to the launch and staging of unmanned solar system exploration missions. The second domain is geosynchronous Earth orbit (GEO) and cislunar space. Activities here include all GEO missions and operations, both unmanned and manned, and all transport of materials and crews between LEO and the vicinity of the Moon. The third domain is the Moon itself. Lunar activities are to include both orbiting and landing missions; the landings may be either unmanned or manned. The last domain is Mars. Missions to Mars will initially be unmanned but they will eventually be manned. Program elements and descriptions are discussed as are critiques of the NASA baseline.

  5. Research Experience for Teachers at Green Bank: High-Precision Calibration, Baselines and Nonlinearities with the GBT

    NASA Astrophysics Data System (ADS)

    Hynes, Shelly; Maddalena, R. J.; Figura, C.

    2006-12-01

    The traditional methods for calibrating single-dish radio telescopes assume that the system gain is linear: detected power is taken to be proportional to the power incident on the antenna. The assumption is wrong at some low level and noticeably breaks down when observing an object that has a large dynamic range. The high sensitivity, clean beam, and very stable electronics of the Green Bank Telescope (GBT) allow us to detect nonlinearities that would be masked in most other radio telescopes. In particular, the signal processing components of the GBT produce an output power that exhibits at least a quadratic dependence on incident power. Our study indicates that measuring and compensating for the nonlinearity is rather trivial and improves calibration when observing objects with a high dynamic range. Once measured, the nonlinearity is shown to be stable over a typical observing run ( 6-8 hours) with evidence of stability for up to several weeks. We also investigated ways to improve spectral-line calibration and baseline shape when observing over a band that is many GHz wide, as is typical with many high frequency GBT projects. We have found that baselines are seriously degraded when using the traditional methods of calibration via scalar values for the system temperature and calibration noise diode that are averaged over the entire bandwidth of the observations. System calibration and baselines are shown to be substantially improved when we use noise diode and system temperature values that have a frequency resolution of a few MHz. Incorporating this research and the general topic of radio astronomy into the high school science classroom will also be discussed. This work was funded in part by the NSF-RET program.

  6. Experiments and simulations of a shocked right-cylinder perturbation

    SciTech Connect

    Cheng, K. T.; Logory, L.; Smith, D. E.

    1998-09-04

    We have conducted a series of experiments using the Nova laser facility at LLNL and corresponding simulations using the two-dimensional, Arbitrary Lagrangian-Eulerian hydrodynamics code CALE. The purpose of this work was to study the shock-driven, hydrodynamic behavior of a right-cylinder perturbation. The accuracy of our simulations is examined by comparison with the experiments.

  7. Simulations of MATROSHKA experiment outside the ISS using PHITS

    NASA Astrophysics Data System (ADS)

    Puchalska, M.; Sihver, L.; Sato, T.; Berger, T.; Reitz, G.

    2012-08-01

    The radiation environment at the altitude of the International Space Station (ISS) is substantially different than anything typically encountered on Earth in both the character of the radiation field and the significantly higher dose rates. Concerns about the biological effects on humans of this highly complex natural radiation field are increasing due to higher amount of astronauts performing long-duration missions onboard the ISS and especially if looking into planned future manned missions to Mars. In order to begin the process of predicting the dose levels seen by the organs of an astronaut, being the prerequisite for radiation risk calculations, it is necessary to understand the character of the radiation environment both in- and outside of the ISS as well as the relevant contributions from the radiation field to the organ doses. In this paper the three-dimensional Monte Carlo Particle and Heavy Ion Transport code System (PHITS) and a voxel-based numerical human model NUNDO (Numerical RANDO) were used to estimate the radiation load of human organs during a long term activity outside the ISS. The baseline measured data was generated with the MATROSHKA-1 (MTR-1) experiment taking place from February 2004 up to October 2005 outside the Russian Zvezda module of the ISS, thereby simulating a long term extravehicular activity (EVA) of an astronaut. The organ absorbed dose values calculated by PHITS for the inner organs are in a good agreement with the experimental data. However, a rather large disagreement was observed for the most outer organs. This disagreement appears to be due to the strong dependence that the thickness of the applied carbon fiber container, acting as the EVA suit of the astronaut, has on the effects caused by the trapped electron (TE) component. The organ dose equivalent values for the deeper organs are a factor of two lower than the experimental data. The detailed reason behind this is still under investigation.

  8. Precision Selenodesy via Differential Very-Long-Baseline Interferometry. Ph.D. Thesis; [Apollo lunar surface experiments package

    NASA Technical Reports Server (NTRS)

    King, R. W., Jr.

    1975-01-01

    The technique of differential very-long baseline interferometry was used to measure the relative positions of the ALSEP transmitters at the Apollo 12, 14, 15, 16, and 17 lunar landing sites with uncertainties less than 0.005 of geocentric arc. These measurements yielded improved determinations of the selenodetic coordinates of the Apollo landing sites, and of the physical libration of the moon. By means of a new device, the differential Doppler receiver (DDR), instrumental errors were reduced to less than the equivalent of 0.001. DDRs were installed in six stations of the NASA spaceflight tracking and data network and used in an extensive program of observations beginning in March 1973.

  9. Comparison of secondary electron emission simulation to experiment.

    SciTech Connect

    Insepov, Z.; Ivanov, V.; Jokela, S. J.; Veryovkin, I.; Zinovev, A.; Frisch, H.

    2011-05-01

    Monte Carlo simulation, empirical theories, and close comparison to experiment were used to parameterize the secondary electron emission (SEE) yields of several highly emissive materials for microchannel plates. In addition, a detailed experiment and analysis of gold were carried out at Argonne National Laboratory. The simulation results will be used in the selection of emissive and resistive materials for deposition and characterization experiments that will be conducted by a large-area fast detector project at Argonne.

  10. Computational Fluid Dynamics (CFD) simulation of the Madison Dynamo Experiment.

    NASA Astrophysics Data System (ADS)

    Haehn, N. S.; Forest, C. B.; Weber, C. R.; Kendrick, R. D.; Taylor, N. Z.; Oakley, J. G.; Bonazza, R.; Spence, Erik

    2007-11-01

    The Madison Dynamo Experiment is designed to study a self-generated magnetic field called a dynamo. The flow characteristics of a water experiment that is dimensionally similar to the liquid sodium experiment has been modeled using the Computational Fluid Dynamics (CFD) software Fluent. Results from the CFD simulations are used to confirm flow characteristics measured experimentally by both Laser Doppler Velocimetry (LDV) and Particle Imaging Velocimetry (PIV). Simulations can also give insight into the flow characteristics in regions of the experiment which are not accessible via the LDV and PIV systems. The results from the simulations are also used as input for a MHD code to predict the threshold for Dynamo onset. The CFD simulations -- in conjunction with the MHD dynamo prediction code -- can be used to design modifications to the experiment to minimize costly changes. The CFD code has shown that the addition of an equatorial baffle along with several poloidal baffles can lower the threshold for Dynamo onset.

  11. Supersonic jet noise prediction and noise source investigation for realistic baseline and chevron nozzles based on hybrid RANS/LES simulations

    NASA Astrophysics Data System (ADS)

    Du, Yongle

    Jet noise simulations have been performed for a military-style baseline nozzle and a chevron nozzle with design Mach numbers of Md = 1:5 operating at several off-design conditions. The objective of the current numerical study is to provide insight into the noise generation mechanisms of shock-containing supersonic hot jets and the noise reduction mechanisms of chevron nozzles. A hybrid methodology combining advanced CFD technologies and the acoustic analogy is used for supersonic jet noise simulations. Unsteady Reynolds-averaged Navier-Stokes (URANS) equations are solved to predict the turbulent noise sources in the jet flows. A modified version of the Detached Eddy Simulation (DES) approach is used to avoid excessive damping of fine scale turbulent fluctuations. A multiblock structured mesh topology is used to represent complex nozzle geometries, including the faceted inner contours and finite nozzle thickness. A block interface condition is optimized for the complex multiblock mesh topology to avoid the centerline singularity. A fourth-order Dispersion-Relation-Preserving (DRP) scheme is used for spatial discretization. To enable efficient calculations, a dual time-stepping method is used in addition to parallel computation using MPI. Both multigrid and implicit residual smoothing are used to accelerate the convergence rate of sub-iterations in the fictitious time domain. Noise predictions are made with the permeable surface Ffowcs Williams and Hawkings (FWH) solution. All the numerical methods have been implemented in the jet flow simulation code "CHOPA" and the noise prediction code "PSJFWH". The computer codes have been validated with several benchmark cases. A preliminary study has been performed for an under-expanded baseline nozzle jet with Mj = 1:56 to validate the accuracy of the jet noise simulations. The results show that grid refinement around the jet potential core and the use of a lower artificial dissipation improve the resolution of the predicted

  12. Rolling motion: experiments and simulations focusing on sliding friction forces

    NASA Astrophysics Data System (ADS)

    Onorato, Pasquale; Malgieri, Massimiliano; De Ambrosis, Anna

    2016-05-01

    The paper presents an activity sequence aimed at elucidating the role of sliding friction forces in determining/shaping the rolling motion. The sequence is based on experiments and computer simulations and it is devoted both to high school and undergraduate students. Measurements are carried out by using the open source Tracker Video Analysis software, while interactive simulations are realized by means of Algodoo, a freeware 2D-simulation software. Data collected from questionnaires before and after the activities, and from final reports, show the effectiveness of combining simulations and Video Based Analysis experiments in improving students' understanding of rolling motion.

  13. Comparison of EGS5 Simulations with Experiment

    SciTech Connect

    Nelson, W.Ralph; Field, Clive; /SLAC

    2006-12-01

    Simulations, made using EGS5, of the longitudinal and radial distributions of energy deposition of electrons of various energies are compared with experimental results in the literature. Energies and materials are: 1 GeV in water and aluminum; 6 GeV in aluminum, copper and lead; and (longitudinal only) 28.5 GeV in alumina (Al{sub 2}O{sub 3}). There is general agreement within a few percent over most of the shower profile. Substantial discrepancies are noted at depths far beyond shower maximum, reaching {approx}30-50% in the cases of lead and copper at 6 GeV.

  14. CFD simulation of DEBORA boiling experiments

    NASA Astrophysics Data System (ADS)

    Rzehak, Roland; Krepper, Eckhard

    2012-08-01

    In this work we investigate the present capabilities of computational fluid dynamics for wall boiling. The computational model used combines the Euler/Euler two-phase flow description with heat flux partitioning. This kind of modeling was previously applied to boiling water under high pressure conditions relevant to nuclear power systems. Similar conditions in terms of the relevant non-dimensional numbers have been realized in the DEBORA tests using dichlorodifluoromethane (R12) as the working fluid. This facilitated measurements of radial profiles for gas volume fraction, gas velocity, bubble size and liquid temperature as well as axial profiles of wall temperature. After reviewing the theoretical and experimental basis of correlations used in the ANSYS CFX model used for the calculations, we give a careful assessment of the necessary recalibrations to describe the DEBORA tests. The basic CFX model is validated by a detailed comparison to the experimental data for two selected test cases. Simulations with a single set of calibrated parameters are found to give reasonable quantitative agreement with the data for several tests within a certain range of conditions and reproduce the observed tendencies correctly. Several model refinements are then presented each of which is designed to improve one of the remaining deviations between simulation and measurements. Specifically we consider a homogeneous MUSIG model for the bubble size, modified bubble forces, a wall function for turbulent boiling flow and a partial slip boundary condition for the liquid phase. Finally, needs for further model developments are identified and promising directions discussed.

  15. Phonocatalysis. An ab initio simulation experiment

    NASA Astrophysics Data System (ADS)

    Kim, Kwangnam; Kaviany, Massoud

    2016-06-01

    Using simulations, we postulate and show that heterocatalysis on large-bandgap semiconductors can be controlled by substrate phonons, i.e., phonocatalysis. With ab initio calculations, including molecular dynamic simulations, the chemisorbed dissociation of XeF6 on h-BN surface leads to formation of XeF4 and two surface F/h-BN bonds. The reaction pathway and energies are evaluated, and the sorption and reaction emitted/absorbed phonons are identified through spectral analysis of the surface atomic motion. Due to large bandgap, the atomic vibration (phonon) energy transfer channels dominate and among them is the match between the F/h-BN covalent bond stretching and the optical phonons. We show that the chemisorbed dissociation (the pathway activation ascent) requires absorption of large-energy optical phonons. Then using progressively heavier isotopes of B and N atoms, we show that limiting these high-energy optical phonons inhibits the chemisorbed dissociation, i.e., controllable phonocatalysis.

  16. Analyzing Complex Metabolomic Networks: Experiments and Simulation

    NASA Astrophysics Data System (ADS)

    Steuer, R.; Kurths, J.; Fiehn, O.; Weckwerth, W.

    2002-03-01

    In the recent years, remarkable advances in molecular biology have enabled us to measure the behavior of complex regularity networks underlying biological systems. In particular, high throughput techniques, such as gene expression arrays, allow a fast acquisition of a large number of simultaneously measured variables. Similar to gene expression, the analysis of metabolomic datasets results in a huge number of metabolite co-regulations: Metabolites are the end products of cellular regulatory processes, their level can be regarded as the ultimate response to genetic or environmental changes. In this presentation we focus on the topological description of such networks, using both, experimental data and simulations. In particular, we discuss the possibility to deduce novel links between metabolites, using concepts from (nonlinear) time series analysis and information theory.

  17. Magnetized laboratory plasma jets: Experiment and simulation

    NASA Astrophysics Data System (ADS)

    Schrafel, Peter; Bell, Kate; Greenly, John; Seyler, Charles; Kusse, Bruce

    2015-01-01

    Experiments involving radial foils on a 1 M A , 100 n s current driver can be used to study the ablation of thin foils and liners, produce extreme conditions relevant to laboratory astrophysics, and aid in computational code validation. This research focuses on the initial ablation phase of a 20 μ m Al foil (8111 alloy), in a radial configuration, driven by Cornell University's COBRA pulsed power generator. In these experiments ablated surface plasma (ASP) on the top side of the foil and a strongly collimated axial plasma jet are observed developing midway through the current rise. With experimental and computational results this work gives a detailed description of the role of the ASP in the formation of the plasma jet with and without an applied axial magnetic field. This ˜1 T field is applied by a Helmholtz-coil pair driven by a slow, 150 μ s current pulse and penetrates the load hardware before arrival of the COBRA pulse. Several effects of the applied magnetic field are observed: (1) without the field extreme-ultraviolet emission from the ASP shows considerable azimuthal asymmetry while with the field the ASP develops azimuthal motion that reduces this asymmetry, (2) this azimuthal motion slows the development of the jet when the field is applied, and (3) with the magnetic field the jet becomes less collimated and has a density minimum (hollowing) on the axis. PERSEUS, an XMHD code, has qualitatively and quantitatively reproduced all these experimental observations. The differences between this XMHD and an MHD code without a Hall current and inertial effects are discussed. In addition the PERSEUS results describe effects we were not able to resolve experimentally and suggest a line of future experiments with better diagnostics.

  18. Magnetized laboratory plasma jets: experiment and simulation.

    PubMed

    Schrafel, Peter; Bell, Kate; Greenly, John; Seyler, Charles; Kusse, Bruce

    2015-01-01

    Experiments involving radial foils on a 1 MA, 100 ns current driver can be used to study the ablation of thin foils and liners, produce extreme conditions relevant to laboratory astrophysics, and aid in computational code validation. This research focuses on the initial ablation phase of a 20 μm Al foil (8111 alloy), in a radial configuration, driven by Cornell University's COBRA pulsed power generator. In these experiments ablated surface plasma (ASP) on the top side of the foil and a strongly collimated axial plasma jet are observed developing midway through the current rise. With experimental and computational results this work gives a detailed description of the role of the ASP in the formation of the plasma jet with and without an applied axial magnetic field. This ∼1 T field is applied by a Helmholtz-coil pair driven by a slow, 150 μs current pulse and penetrates the load hardware before arrival of the COBRA pulse. Several effects of the applied magnetic field are observed: (1) without the field extreme-ultraviolet emission from the ASP shows considerable azimuthal asymmetry while with the field the ASP develops azimuthal motion that reduces this asymmetry, (2) this azimuthal motion slows the development of the jet when the field is applied, and (3) with the magnetic field the jet becomes less collimated and has a density minimum (hollowing) on the axis. PERSEUS, an XMHD code, has qualitatively and quantitatively reproduced all these experimental observations. The differences between this XMHD and an MHD code without a Hall current and inertial effects are discussed. In addition the PERSEUS results describe effects we were not able to resolve experimentally and suggest a line of future experiments with better diagnostics. PMID:25679726

  19. Simulating Terrorist Cells: Experiments and Mathematical Theory

    NASA Astrophysics Data System (ADS)

    McGough, Lauren

    How well do mathematical models of terrorist cells apply to the reallife struggle against terrorism? Certainly, mathematical models have been useful in the past for military planning and predicting the behavior of U.S. adversaries, but how well do mathematical projections of terrorist behavior actually hold up when tested on living people and real situations? This paper first presents a mathematical model of terrorist cells and their functionality, and then discusses the procedure and results of an experiment conducted to test this model’s theoretical projections by comparing them with experimental results, thus confronting the question of theory versus reality.

  20. Passive walker that can walk down steps: simulations and experiments

    NASA Astrophysics Data System (ADS)

    Liu, Ning; Li, Junfeng; Wang, Tianshu

    2008-10-01

    A planar passive walking model with straight legs and round feet was discussed. This model can walk down steps, both on stairs with even steps and with random steps. Simulations showed that models with small moments of inertia can navigate large height steps. Period-doubling has been observed when the space between steps grows. This period-doubling has been validated by experiments, and the results of experiments were coincident with the simulation.

  1. Theory, Image Simulation, and Data Analysis of Chemical Release Experiments

    NASA Technical Reports Server (NTRS)

    Wescott, Eugene M.

    1994-01-01

    The final phase of Grant NAG6-1 involved analysis of physics of chemical releases in the upper atmosphere and analysis of data obtained on previous NASA sponsored chemical release rocket experiments. Several lines of investigation of past chemical release experiments and computer simulations have been proceeding in parallel. This report summarizes the work performed and the resulting publications. The following topics are addressed: analysis of the 1987 Greenland rocket experiments; calculation of emission rates for barium, strontium, and calcium; the CRIT 1 and 2 experiments (Collisional Ionization Cross Section experiments); image calibration using background stars; rapid ray motions in ionospheric plasma clouds; and the NOONCUSP rocket experiments.

  2. Computer Simulation of Laboratory Experiments: An Unrealized Potential.

    ERIC Educational Resources Information Center

    Magin, D. J.; Reizes, J. A.

    1990-01-01

    Discussion of the use of computer simulation for laboratory experiments in undergraduate engineering education focuses on work at the University of New South Wales in the instructional design and software development of a package simulating a heat exchange device. The importance of integrating theory, design, and experimentation is also discussed.…

  3. Computer Simulation of the Population Growth (Schizosaccharomyces Pombe) Experiment.

    ERIC Educational Resources Information Center

    Daley, Michael; Hillier, Douglas

    1981-01-01

    Describes a computer program (available from authors) developed to simulate "Growth of a Population (Yeast) Experiment." Students actively revise the counting techniques with realistically simulated haemocytometer or eye-piece grid and are reminded of the necessary dilution technique. Program can be modified to introduce such variables as…

  4. Optimizing Chromatographic Separation: An Experiment Using an HPLC Simulator

    ERIC Educational Resources Information Center

    Shalliker, R. A.; Kayillo, S.; Dennis, G. R.

    2008-01-01

    Optimization of a chromatographic separation within the time constraints of a laboratory session is practically impossible. However, by employing a HPLC simulator, experiments can be designed that allow students to develop an appreciation of the complexities involved in optimization procedures. In the present exercise, a HPLC simulator from "JCE…

  5. PHITS simulations of the Matroshka experiment

    NASA Astrophysics Data System (ADS)

    Gustafsson, K.; Sihver, L.; Mancusi, D.; Sato, T.; Reitz, G.; Berger, T.

    2010-11-01

    The radiation environment in space is very different from the one encountered on Earth. In addition to the sparsely ionizing radiation, there are particles of different Z with energies ranging from keV up to hundreds of GeV which can cause severe damage to both electronics and humans. It is therefore important to understand the interactions of these highly ionizing particles with different materials such as the hull of space vehicles, human organs and electronics. We have used the Particle and Heavy-Ion Transport code System (PHITS), which is a three-dimensional Monte Carlo code able to calculate interactions and transport of particles and heavy ions with energies up to 100 GeV/nucleon in most matter. PHITS is developed and maintained by a collaboration between RIST (Research Organization for Information Science & Technology), JAEA (Japan Atomic Energy Agency), KEK (High Energy Accelerator Research Organization), Japan and Chalmers University of Technology, Sweden. For the purpose of examining the applicability of PHITS to the shielding design we have simulated the ESA facility Matroshka (MTR) designed and lead by the German Aerospace Center (DLR). Preliminary results are presented and discussed in this paper.

  6. Natural streamflow simulation for two largest river basins in Poland: a baseline for identification of flow alterations

    NASA Astrophysics Data System (ADS)

    Piniewski, Mikołaj

    2016-05-01

    The objective of this study was to apply a previously developed large-scale and high-resolution SWAT model of the Vistula and the Odra basins, calibrated with the focus of natural flow simulation, in order to assess the impact of three different dam reservoirs on streamflow using the Indicators of Hydrologic Alteration (IHA). A tailored spatial calibration approach was designed, in which calibration was focused on a large set of relatively small non-nested sub-catchments with semi-natural flow regime. These were classified into calibration clusters based on the flow statistics similarity. After performing calibration and validation that gave overall positive results, the calibrated parameter values were transferred to the remaining part of the basins using an approach based on hydrological similarity of donor and target catchments. The calibrated model was applied in three case studies with the purpose of assessing the effect of dam reservoirs (Włocławek, Siemianówka and Czorsztyn Reservoirs) on streamflow alteration. Both the assessment based on gauged streamflow (Before-After design) and the one based on simulated natural streamflow showed large alterations in selected flow statistics related to magnitude, duration, high and low flow pulses and rate of change. Some benefits of using a large-scale and high-resolution hydrological model for the assessment of streamflow alteration include: (1) providing an alternative or complementary approach to the classical Before-After designs, (2) isolating the climate variability effect from the dam (or any other source of alteration) effect, (3) providing a practical tool that can be applied at a range of spatial scales over large area such as a country, in a uniform way. Thus, presented approach can be applied for designing more natural flow regimes, which is crucial for river and floodplain ecosystem restoration in the context of the European Union's policy on environmental flows.

  7. Transport simulations of ohmic ignition experiment: IGNITEX

    SciTech Connect

    Uckan, N.A.; Howe, H.C.

    1987-12-01

    The IGNITEX device, proposed by Rosenbluth et al., is a compact, super-high-field, high-current, copper-coil tokamak envisioned to reach ignition with ohmic (OH) heating alone. Several simulations of IGNITEX were made with a 0-D global model and with the 1-D PROCTR transport code. It is shown that OH ignition is a sensitive function of the assumptions about density profile, wall reflectivity of synchrotron radiation, impurity radiation, plasma edge conditions, and additional anomalous losses. In IGNITEX, OH ignition is accessible with nearly all scalings based on favorable OH confinement (such as neo-Alcator). Also, OH ignition appears to be accessible for most (not all) L-mode scalings (such as Kaye-Goldston), provided that the density profile is not too broad (parabolic or more peaked profiles are needed), Z/sub eff/ is not too large, and anomalous radiation and alpha losses and/or other enhanced transport losses (eta/sub i/ modes, edge convective energy losses, etc.) are not present. In IGNITEX, because the figure-of-merit parameters are large, ignition can be accessed (either with OH heating alone or with the aid of a small amount of auxiliary power) at relatively low beta, far from stability limits. Once the plasma is ignited, thermal runaway is prevented naturally by a combination of increased synchrotron radiation, burnout of the fuel in the plasma core and replacement by thermal alphas, and the reduction in the thermal plasma confinement assumed in L-mode-like scalings. 12 refs., 5 figs., 1 tab.

  8. An R package for simulation experiments evaluating clinical trial designs.

    PubMed

    Wang, Yuanyuan; Day, Roger

    2010-01-01

    This paper presents an open-source application for evaluating competing clinical trial (CT) designs using simulations. The S4 system of classes and methods is utilized. Using object-oriented programming provides extensibility through careful, clear interface specification; using R, an open-source widely-used statistical language, makes the application extendible by the people who design CTs: biostatisticians. Four key classes define the specifications of the population models, CT designs, outcome models and evaluation criteria. Five key methods define the interfaces for generating patient baseline characteristics, stopping rule, assigning treatment, generating patient outcomes and calculating the criteria. Documentation of their connections with the user input screens, with the central simulation loop, and with each other faciliates the extensibility. New subclasses and instances of existing classes meeting these interfaces can integrate immediately into the application. To illustrate the application, we evaluate the effect of patient pharmacokinetic heterogeneity on the performance of a common Phase I "3+3" design. PMID:21347151

  9. Modeling and Simulation of Fluid Mixing Laser Experiments and Supernova

    SciTech Connect

    James Glimm

    2009-06-04

    The three year plan for this project was to develop novel theories and advanced simulation methods leading to a systematic understanding of turbulent mixing. A primary focus is the comparison of simulation models (Direct Numerical Simulation (DNS), Large Eddy Simulations (LES), full two fluid simulations and subgrid averaged models) to experiments. The comprehension and reduction of experimental and simulation data are central goals of this proposal. We model 2D and 3D perturbations of planar or circular interfaces. We compare these tests with models derived from averaged equations (our own and those of others). As a second focus, we develop physics based subgrid simulation models of diffusion across an interface, with physical but no numerical mass diffusion. Multiple layers and reshock are considered here.

  10. Plasmonic nanoparticles: fabrication, simulation and experiments

    NASA Astrophysics Data System (ADS)

    Gonçalves, Manuel R.

    2014-05-01

    Some of the optical effects produced by plasmonic nanoparticles have been known since antiquity. However, the physical understanding of these properties only began in the first decade of the 20th century. The discovery of the dispersion relation of surface plasmons, almost 40 years later, unified the physical description of the plasmonic phenomena. Later, advances in nanofabrication initiated a revolution in the preparation of metallic nanostructures supporting surface plasmons. In parallel, modern electromagnetic computational methods have permitted the theoretical investigation of the optics of nanoscale and tailor plasmonic particles for experiments. A large range of applications based on the properties of surface plasmons has been recently developed, namely, strong light localization, elastic and inelastic scattering of light and interaction between optical and other physical properties of matter. In this topical review I address the preparation techniques of single plasmonic nanostructures, supported in homogeneous media or on substrates, and the study of their optical properties by experimental and theoretical methods. In the last decade new research directions were initiated towards metamaterials, nanoantennas, plasmonic trapping and heating. The study of quantum effects in plasmonic nanoparticles has attracted broad attention. A summary of the latest developments is presented.

  11. "FluSpec": A Simulated Experiment in Fluorescence Spectroscopy

    ERIC Educational Resources Information Center

    Bigger, Stephen W.; Bigger, Andrew S.; Ghiggino, Kenneth P.

    2014-01-01

    The "FluSpec" educational software package is a fully contained tutorial on the technique of fluorescence spectroscopy as well as a simulator on which experiments can be performed. The procedure for each of the experiments is also contained within the package along with example analyses of results that are obtained using the software.

  12. Albedo in the ATIC Experiment: Results of Measurements and Simulation

    NASA Technical Reports Server (NTRS)

    Sokolskaya, N. V.; Adams, J. H., Jr.; Ahn, H. S.; Bashindzhagyan, G. L.; Batkov, K. E.; Chang, J.; Christl, M.; Fazely, A. R.; Ganel, O.; Gunasingha, R. M.

    2004-01-01

    Characteristics of albedo, or backscatter current, providing a 'background' for calorimeter experiments in high energy cosmic rays are analyzed. The comparison of experimental data obtained in the flights of the ATIC spectrometer is made with simulations performed using the GEANT 3.21 code. The influence of the backscatter on charge resolution in the ATIC experiment is discussed.

  13. Experiences with linear solvers for oil reservoir simulation problems

    SciTech Connect

    Joubert, W.; Janardhan, R.; Biswas, D.; Carey, G.

    1996-12-31

    This talk will focus on practical experiences with iterative linear solver algorithms used in conjunction with Amoco Production Company`s Falcon oil reservoir simulation code. The goal of this study is to determine the best linear solver algorithms for these types of problems. The results of numerical experiments will be presented.

  14. Synthetic Vision Systems - Operational Considerations Simulation Experiment

    NASA Technical Reports Server (NTRS)

    Kramer, Lynda J.; Williams, Steven P.; Bailey, Randall E.; Glaab, Louis J.

    2007-01-01

    Synthetic vision is a computer-generated image of the external scene topography that is generated from aircraft attitude, high-precision navigation information, and data of the terrain, obstacles, cultural features, and other required flight information. A synthetic vision system (SVS) enhances this basic functionality with real-time integrity to ensure the validity of the databases, perform obstacle detection and independent navigation accuracy verification, and provide traffic surveillance. Over the last five years, NASA and its industry partners have developed and deployed SVS technologies for commercial, business, and general aviation aircraft which have been shown to provide significant improvements in terrain awareness and reductions in the potential for Controlled-Flight-Into-Terrain incidents/accidents compared to current generation cockpit technologies. It has been hypothesized that SVS displays can greatly improve the safety and operational flexibility of flight in Instrument Meteorological Conditions (IMC) to a level comparable to clear-day Visual Meteorological Conditions (VMC), regardless of actual weather conditions or time of day. An experiment was conducted to evaluate SVS and SVS-related technologies as well as the influence of where the information is provided to the pilot (e.g., on a Head-Up or Head-Down Display) for consideration in defining landing minima based upon aircraft and airport equipage. The "operational considerations" evaluated under this effort included reduced visibility, decision altitudes, and airport equipage requirements, such as approach lighting systems, for SVS-equipped aircraft. Subjective results from the present study suggest that synthetic vision imagery on both head-up and head-down displays may offer benefits in situation awareness; workload; and approach and landing performance in the visibility levels, approach lighting systems, and decision altitudes tested.

  15. Synthetic vision systems: operational considerations simulation experiment

    NASA Astrophysics Data System (ADS)

    Kramer, Lynda J.; Williams, Steven P.; Bailey, Randall E.; Glaab, Louis J.

    2007-04-01

    Synthetic vision is a computer-generated image of the external scene topography that is generated from aircraft attitude, high-precision navigation information, and data of the terrain, obstacles, cultural features, and other required flight information. A synthetic vision system (SVS) enhances this basic functionality with real-time integrity to ensure the validity of the databases, perform obstacle detection and independent navigation accuracy verification, and provide traffic surveillance. Over the last five years, NASA and its industry partners have developed and deployed SVS technologies for commercial, business, and general aviation aircraft which have been shown to provide significant improvements in terrain awareness and reductions in the potential for Controlled-Flight-Into-Terrain incidents / accidents compared to current generation cockpit technologies. It has been hypothesized that SVS displays can greatly improve the safety and operational flexibility of flight in Instrument Meteorological Conditions (IMC) to a level comparable to clear-day Visual Meteorological Conditions (VMC), regardless of actual weather conditions or time of day. An experiment was conducted to evaluate SVS and SVS-related technologies as well as the influence of where the information is provided to the pilot (e.g., on a Head-Up or Head-Down Display) for consideration in defining landing minima based upon aircraft and airport equipage. The "operational considerations" evaluated under this effort included reduced visibility, decision altitudes, and airport equipage requirements, such as approach lighting systems, for SVS-equipped aircraft. Subjective results from the present study suggest that synthetic vision imagery on both head-up and head-down displays may offer benefits in situation awareness; workload; and approach and landing performance in the visibility levels, approach lighting systems, and decision altitudes tested.

  16. Attitudes of Nurse and Physician trainees towards an interprofessional simulated education experience on Pain Assessment and Management.

    PubMed

    Salam, Tabassum; Saylor, Jennifer L; Cowperthwait, Amy Lynn

    2015-05-01

    An interprofessional group of educators from multiple institutions piloted a simulation-based learning experience focusing on acute pain management. The participants in the program were resident physicians-novice nurse dyads, and medical student-nursing student dyads from large universities and a magnet health care system. Each dyad was challenged to assess and manage acute pain in a simulated hospitalized patient using effective collaboration skills. The simulations included pre-debriefing, simulation, and a debriefing session. Participants completed pre- and post-surveys measuring confidence in pain management and attitudes toward physician-nurse collaboration. There was a significant positive shift in the confidence of the learners' ability to assess and manage acute pain in a hospitalized patient after the simulation and debriefing (23.2% strongly agreed versus 7% at baseline). Participants' attitudes regarding education to enhance interprofessional collaboration improved after the simulation experience (83.9% strongly agreed versus 73.7% at baseline). Based on these encouraging findings, we are extending this interprofessional experience to a larger group of learners with the same targeted dyads. PMID:25153772

  17. Altered baseline brain activity with 72 h of simulated microgravity--initial evidence from resting-state fMRI.

    PubMed

    Liao, Yang; Zhang, Jinsong; Huang, Zhiping; Xi, Yibin; Zhang, Qianru; Zhu, Tianli; Liu, Xufeng

    2012-01-01

    To provide the basis and reference to further insights into the neural activity of the human brain in a microgravity environment, we discuss the amplitude changes of low-frequency brain activity fluctuations using a simulated microgravity model. Twelve male participants between 24 and 31 years old received resting-state fMRI scans in both a normal condition and after 72 hours in a -6° head down tilt (HDT). A paired sample t-test was used to test the amplitude differences of low-frequency brain activity fluctuations between these two conditions. With 72 hours in a -6° HDT, the participants showed a decreased amplitude of low-frequency fluctuations in the left thalamus compared with the normal condition (a combined threshold of P<0.005 and a minimum cluster size of 351 mm(3) (13 voxels), which corresponded with the corrected threshold of P<0.05 determined by AlphaSim). Our findings indicate that a gravity change-induced redistribution of body fluid may disrupt the function of the left thalamus in the resting state, which may contribute to reduced motor control abilities and multiple executive functions in astronauts in a microgravity environment. PMID:23285086

  18. Simulated Performance of the Orbiting Wide-angle Light Collectors (OWL) Experiment

    NASA Technical Reports Server (NTRS)

    Krizmanic, J. F.; Whitaker, Ann F. (Technical Monitor)

    2001-01-01

    The Orbiting Wide-angle Light collectors (OWL) experiment is in NASA's mid-term strategic plan and will stereoscopically image, from equatorial orbit, the air fluorescence signal generated by airshowers induced by the ultrahigh energy (E greater than few x 10(exp 19) eV) component of the cosmic radiation. The use of a space-based platform enables an extremely large event acceptance aperture and thus will allow a high statistics measurement of these rare events. Detailed Monte Carlo simulations are required to quantify the physics potential of the mission as well as optimize the instrumental parameters. This paper reports on the results of the GSFC Monte Carlo simulation for two different, OWL instrument baseline designs. These results indicate that, assuming a continuation of the cosmic ray spectrum (theta approximately E(exp -2.75), OWL could have an event rate of 4000 events/year with E greater than or equal to 10(exp 20) eV. Preliminary results, based upon these Monte Carlo simulations, indicate that events can be accurately reconstructed in the detector focal plane arrays for the OWL instrument baseline designs under consideration.

  19. Simulations of Ground and Space-Based Oxygen Atom Experiments

    NASA Technical Reports Server (NTRS)

    Finchum, A. (Technical Monitor); Cline, J. A.; Minton, T. K.; Braunstein, M.

    2003-01-01

    A low-earth orbit (LEO) materials erosion scenario and the ground-based experiment designed to simulate it are compared using the direct-simulation Monte Carlo (DSMC) method. The DSMC model provides a detailed description of the interactions between the hyperthermal gas flow and a normally oriented flat plate for each case. We find that while the general characteristics of the LEO exposure are represented in the ground-based experiment, multi-collision effects can potentially alter the impact energy and directionality of the impinging molecules in the ground-based experiment. Multi-collision phenomena also affect downstream flux measurements.

  20. Monte Carlo Strategies for Selecting Parameter Values in Simulation Experiments.

    PubMed

    Leigh, Jessica W; Bryant, David

    2015-09-01

    Simulation experiments are used widely throughout evolutionary biology and bioinformatics to compare models, promote methods, and test hypotheses. The biggest practical constraint on simulation experiments is the computational demand, particularly as the number of parameters increases. Given the extraordinary success of Monte Carlo methods for conducting inference in phylogenetics, and indeed throughout the sciences, we investigate ways in which Monte Carlo framework can be used to carry out simulation experiments more efficiently. The key idea is to sample parameter values for the experiments, rather than iterate through them exhaustively. Exhaustive analyses become completely infeasible when the number of parameters gets too large, whereas sampled approaches can fare better in higher dimensions. We illustrate the framework with applications to phylogenetics and genetic archaeology. PMID:26012871

  1. GFDL's ESM2 global coupled climate-carbon Earth System Models. Part I: physical formulation and baseline simulation characteristics

    USGS Publications Warehouse

    Dunne, John P.; John, Jasmin G.; Adcroft, Alistair J.; Griffies, Stephen M.; Hallberg, Robert W.; Shevalikova, Elena; Stouffer, Ronald J.; Cooke, William; Dunne, Krista A.; Harrison, Matthew J.; Krasting, John P.; Malyshev, Sergey L.; Milly, P.C.D.; Phillipps, Peter J.; Sentman, Lori A.; Samuels, Bonita L.; Spelman, Michael J.; Winton, Michael; Wittenberg, Andrew T.; Zadeh, Niki

    2012-01-01

    We describe the physical climate formulation and simulation characteristics of two new global coupled carbon-climate Earth System Models, ESM2M and ESM2G. These models demonstrate similar climate fidelity as the Geophysical Fluid Dynamics Laboratory's previous CM2.1 climate model while incorporating explicit and consistent carbon dynamics. The two models differ exclusively in the physical ocean component; ESM2M uses Modular Ocean Model version 4.1 with vertical pressure layers while ESM2G uses Generalized Ocean Layer Dynamics with a bulk mixed layer and interior isopycnal layers. Differences in the ocean mean state include the thermocline depth being relatively deep in ESM2M and relatively shallow in ESM2G compared to observations. The crucial role of ocean dynamics on climate variability is highlighted in the El Niño-Southern Oscillation being overly strong in ESM2M and overly weak ESM2G relative to observations. Thus, while ESM2G might better represent climate changes relating to: total heat content variability given its lack of long term drift, gyre circulation and ventilation in the North Pacific, tropical Atlantic and Indian Oceans, and depth structure in the overturning and abyssal flows, ESM2M might better represent climate changes relating to: surface circulation given its superior surface temperature, salinity and height patterns, tropical Pacific circulation and variability, and Southern Ocean dynamics. Our overall assessment is that neither model is fundamentally superior to the other, and that both models achieve sufficient fidelity to allow meaningful climate and earth system modeling applications. This affords us the ability to assess the role of ocean configuration on earth system interactions in the context of two state-of-the-art coupled carbon-climate models.

  2. Computer Simulation of Einstein-Podolsky-Rosen-Bohm Experiments

    NASA Astrophysics Data System (ADS)

    de Raedt, H.; Michielsen, K.

    2016-07-01

    We review an event-based simulation approach which reproduces the statistical distributions of quantum physics experiments by generating detection events one-by-one according to an unknown distribution and without solving a wave equation. Einstein-Podolsky-Rosen-Bohm laboratory experiments are used as an example to illustrate the applicability of this approach. It is shown that computer experiments that employ the same post-selection procedure as the one used in laboratory experiments produce data that is in excellent agreement with quantum theory.

  3. Numerical simulation of experiments in the Giant Planet Facility

    NASA Technical Reports Server (NTRS)

    Green, M. J.; Davy, W. C.

    1979-01-01

    Utilizing a series of existing computer codes, ablation experiments in the Giant Planet Facility are numerically simulated. Of primary importance is the simulation of the low Mach number shock layer that envelops the test model. The RASLE shock-layer code, used in the Jupiter entry probe heat-shield design, is adapted to the experimental conditions. RASLE predictions for radiative and convective heat fluxes are in good agreement with calorimeter measurements. In simulating carbonaceous ablation experiments, the RASLE code is coupled directly with the CMA material response code. For the graphite models, predicted and measured recessions agree very well. Predicted recession for the carbon phenolic models is 50% higher than that measured. This is the first time codes used for the Jupiter probe design have been compared with experiments.

  4. The Impact of Baseline Trend Control on Visual Analysis of Single-Case Data

    ERIC Educational Resources Information Center

    Mercer, Sterett H.; Sterling, Heather E.

    2012-01-01

    The impact of baseline trend control on visual analyses of AB intervention graphs was examined with simulated data at various values of baseline trend, autocorrelation, and effect size. Participants included 202 undergraduate students with minimal training in visual analysis and 10 graduate students and faculty with more training and experience in…

  5. Plasma Simulation for the SHIP Experiment at GDT

    SciTech Connect

    Anikeev, A.V.; Bagryansky, P.A.; Collatz, S.; Noack, K

    2005-01-15

    The concept of the Synthesized Hot Ion Plasmoid (SHIP) experiment at the gas dynamic trap (GDT) facility of the Budker Institute Novosibirsk was presented at the 29{sup th} EPS Conference. During the last year several numerical simulations were made by means of the Integrated Transport Code System (ITCS) to determine the best experimental scenario for getting high plasma parameters. This contribution presents important results of the recent numerical simulations of SHIP by means of the ITCS modules.

  6. Short Rayleigh length free electron laser: Experiments and simulations

    NASA Astrophysics Data System (ADS)

    Crooker, P. P.; Colson, W. B.; Blau, J.; Burggraff, D.; Aguilar, J. Sans; Benson, S.; Neil, G.; Shinn, M.; Evtushenko, P.

    2008-09-01

    We report experiments at Jefferson National Accelerator Facility (Jlab) and computer simulations performed at the Naval Postgraduate School (NPS) designed to probe the small Rayleigh length regime. We compare the gain, power, and sensitivity to mirror and electron beam misalignments as a function of decreasing Rayleigh length. The agreement is quite good, with experiments and simulations showing comparable trends as the Rayleigh length is decreased. In particular, we find that the gain and power do not decrease substantially at short Rayleigh length, contrary to a common Gaussian-mode filling factor argument. Within currently achievable alignment tolerances, the gain and power are still acceptable for FEL operation.

  7. Comparing CTH Simulations and Experiments on Explosively Loaded Rings

    NASA Astrophysics Data System (ADS)

    Braithwaite, C. H.; Aydelotte, B.; Thadhani, N. N.; Williamson, D. M.

    2011-06-01

    A series of experiments were conducted on explosively loaded rings for the purpose of studying fragmentation. In addition to the collection of fragments for analysis, the radial velocity of the expanding ring was measured with PDV and the arrangement was imaged using a high speed camera. Both the ring material and the material used as the explosive container were altered and the results compared with simulations performed in CTH. Good agreement was found between the simulations and the experiments. The maximum radial velocity attained was approximately 450 m/s, which was achieved through loading with a 5g PETN based charge.

  8. Monte Carlo simulation of the Neutrino-4 experiment

    SciTech Connect

    Serebrov, A. P. Fomin, A. K.; Onegin, M. S.; Ivochkin, V. G.; Matrosov, L. N.

    2015-12-15

    Monte Carlo simulation of the two-section reactor antineutrino detector of the Neutrino-4 experiment is carried out. The scintillation-type detector is based on the inverse beta-decay reaction. The antineutrino is recorded by two successive signals from the positron and the neutron. The simulation of the detector sections and the active shielding is performed. As a result of the simulation, the distributions of photomultiplier signals from the positron and the neutron are obtained. The efficiency of the detector depending on the signal recording thresholds is calculated.

  9. Monte Carlo simulation of the Neutrino-4 experiment

    NASA Astrophysics Data System (ADS)

    Serebrov, A. P.; Fomin, A. K.; Onegin, M. S.; Ivochkin, V. G.; Matrosov, L. N.

    2015-12-01

    Monte Carlo simulation of the two-section reactor antineutrino detector of the Neutrino-4 experiment is carried out. The scintillation-type detector is based on the inverse beta-decay reaction. The antineutrino is recorded by two successive signals from the positron and the neutron. The simulation of the detector sections and the active shielding is performed. As a result of the simulation, the distributions of photomultiplier signals from the positron and the neutron are obtained. The efficiency of the detector depending on the signal recording thresholds is calculated.

  10. Modeling and Simulation of Fluid Mixing Laser Experiments and Supernova

    SciTech Connect

    Glimm, James

    2008-06-24

    The three year plan for this project is to develop novel theories and advanced simulation methods leading to a systematic understanding of turbulent mixing. A primary focus is the comparison of simulation models (both Direct Numerical Simulation and subgrid averaged models) to experiments. The comprehension and reduction of experimental and simulation data are central goals of this proposal. We will model 2D and 3D perturbations of planar interfaces. We will compare these tests with models derived from averaged equations (our own and those of others). As a second focus, we will develop physics based subgrid simulation models of diffusion across an interface, with physical but no numerical mass diffusion. We will conduct analytic studies of mix, in support of these objectives. Advanced issues, including multiple layers and reshock, will be considered.

  11. Simulator design for advanced ISDN satellite design and experiments

    NASA Technical Reports Server (NTRS)

    Pepin, Gerald R.

    1992-01-01

    This simulation design task completion report documents the simulation techniques associated with the network models of both the Interim Service ISDN (integrated services digital network) Satellite (ISIS) and the Full Service ISDN Satellite (FSIS) architectures. The ISIS network model design represents satellite systems like the Advanced Communication Technology Satellite (ACTS) orbiting switch. The FSIS architecture, the ultimate aim of this element of the Satellite Communications Applications Research (SCAR) program, moves all control and switching functions on-board the next generation ISDN communication satellite. The technical and operational parameters for the advanced ISDN communications satellite design will be obtained from the simulation of ISIS and FSIS engineering software models for their major subsystems. Discrete events simulation experiments will be performed with these models using various traffic scenarios, design parameters and operational procedures. The data from these simulations will be used to determine the engineering parameters for the advanced ISDN communications satellite.

  12. Numerical Simulation and Cold Modeling experiments on Centrifugal Casting

    NASA Astrophysics Data System (ADS)

    Keerthiprasad, Kestur Sadashivaiah; Murali, Mysore Seetharam; Mukunda, Pudukottah Gopaliengar; Majumdar, Sekhar

    2011-02-01

    In a centrifugal casting process, the fluid flow eventually determines the quality and characteristics of the final product. It is difficult to study the fluid behavior here because of the opaque nature of melt and mold. In the current investigation, numerical simulations of the flow field and visualization experiments on cold models have been carried out for a centrifugal casting system using horizontal molds and fluids of different viscosities to study the effect of different process variables on the flow pattern. The effects of the thickness of the cylindrical fluid annulus formed inside the mold and the effects of fluid viscosity, diameter, and rotational speed of the mold on the hollow fluid cylinder formation process have been investigated. The numerical simulation results are compared with corresponding data obtained from the cold modeling experiments. The influence of rotational speed in a real-life centrifugal casting system has also been studied using an aluminum-silicon alloy. Cylinders of different thicknesses are cast at different rotational speeds, and the flow patterns observed visually in the actual castings are found to be similar to those recorded in the corresponding cold modeling experiments. Reasonable agreement is observed between the results of numerical simulation and the results of cold modeling experiments with different fluids. The visualization study on the hollow cylinders produced in an actual centrifugal casting process also confirm the conclusions arrived at from the cold modeling experiments and numerical simulation in a qualitative sense.

  13. Initial Experiences with Retrieving Similar Objects in Simulation Data

    SciTech Connect

    Cheung, S-C S; Kamath, C

    2003-02-21

    Comparing the output of a physics simulation with an experiment, referred to as 'code validation,' is often done by visually comparing the two outputs. In order to determine which simulation is a closer match to the experiment, more quantitative measures are needed. In this paper, we describe our early experiences with this problem by considering the slightly simpler problem of finding objects in a image that are similar to a given query object. Focusing on a dataset from a fluid mixing problem, we report on our experiments with different features that are used to represent the objects of interest in the data. These early results indicate that the features must be chosen carefully to correctly represent the query object and the goal of the similarity search.

  14. Crack-Detection Experiments on Simulated Turbine Engine Disks in NASA Glenn Research Center's Rotordynamics Laboratory

    NASA Technical Reports Server (NTRS)

    Woike, Mark R.; Abdul-Aziz, Ali

    2010-01-01

    The development of new health-monitoring techniques requires the use of theoretical and experimental tools to allow new concepts to be demonstrated and validated prior to use on more complicated and expensive engine hardware. In order to meet this need, significant upgrades were made to NASA Glenn Research Center s Rotordynamics Laboratory and a series of tests were conducted on simulated turbine engine disks as a means of demonstrating potential crack-detection techniques. The Rotordynamics Laboratory consists of a high-precision spin rig that can rotate subscale engine disks at speeds up to 12,000 rpm. The crack-detection experiment involved introducing a notch on a subscale engine disk and measuring its vibration response using externally mounted blade-tip-clearance sensors as the disk was operated at speeds up to 12 000 rpm. Testing was accomplished on both a clean baseline disk and a disk with an artificial crack: a 50.8-mm- (2-in.-) long introduced notch. The disk s vibration responses were compared and evaluated against theoretical models to investigate how successful the technique was in detecting cracks. This paper presents the capabilities of the Rotordynamics Laboratory, the baseline theory and experimental setup for the crack-detection experiments, and the associated results from the latest test campaign.

  15. Photovoltaic Experiment Using Light from a Solar Simulator Lamp.

    ERIC Educational Resources Information Center

    Chow, R. H.

    1980-01-01

    A photovoltaic cell experiment utilizing the convenience of a solar simulating type lamp is described. Insight into the solid state aspect of a solar cell is gained by the student in studying the characteristics, and deducing from them cell parameters and efficiency. (Author/CS)

  16. A Computer Simulated Experiment in Complex Order Kinetics

    ERIC Educational Resources Information Center

    Merrill, J. C.; And Others

    1975-01-01

    Describes a computer simulation experiment in which physical chemistry students can determine all of the kinetic parameters of a reaction, such as order of the reaction with respect to each reagent, forward and reverse rate constants for the overall reaction, and forward and reverse activation energies. (MLH)

  17. New simulation capability for gamma ray mirror experiments

    SciTech Connect

    Descalle, Marie-Anne; Ruz-Armendariz, Jaime; Decker, Todd; Brejhnolt, Nicolai; Pivovaroff, Michael

    2015-09-28

    This report provides a description of the simulation toolkit developed at Lawrence Livermore National Laboratory to support the design of nuclear safeguards experiments using grazing incidence multilayer mirrors in the energy band of uranium (U) and plutonium (Pu) emission lines. This effort was motivated by the data analysis of a scoping experiment at the Irradiated Fuels Examination Facility (IFEL) at Oak Ridge National Laboratory in FY13 and of a benchmark experiment at the Idaho National Laboratory (INL) in FY14 that highlighted the need for predictive tools built around a ray-tracing capability. This report presents the simulation toolkit and relevant results such as the simulated spectra for TMI, MOX, and ATM106 fuel rods based on spent fuel models provided by Los Alamos National Laboratory and for a virgin high 240Pu-content fuel plate, as well as models of the IFEL and INL experiments implemented in the ray tracing tool. The beam position and height were validated against the INL ~60 keV americium data. Examples of alternate configurations of the optics or experimental set-up illustrate the future use of the simulation suite to guide the next IFEL experimental campaign.

  18. Students' Experiences of Learning Manual Clinical Skills through Simulation

    ERIC Educational Resources Information Center

    Johannesson, Eva; Silen, Charlotte; Kvist, Joanna; Hult, Hakan

    2013-01-01

    Learning manual skills is a fundamental part of health care education, and motor, sensory and cognitive learning processes are essential aspects of professional development. Simulator training has been shown to enhance factors that facilitate motor and cognitive learning. The present study aimed to investigate the students' experiences and…

  19. Anticipating the Experience of Higher Education through Computer Simulation.

    ERIC Educational Resources Information Center

    Entwistle, Noel; And Others

    The development of a principled microcomputer-based adventure game that simulates the experience of higher education for prospective students in British schools is discussed. Playing the game is intended to provide prospective students a "realistic role preview." Consideration is given to an earlier board game and research on student learning on…

  20. Effects of Error Experience When Learning to Simulate Hypernasality

    ERIC Educational Resources Information Center

    Wong, Andus W.-K.; Tse, Andy C.-Y.; Ma, Estella P.-M.; Whitehill, Tara L.; Masters, Rich S. W.

    2013-01-01

    Purpose: The purpose of this study was to evaluate the effects of error experience on the acquisition of hypernasal speech. Method: Twenty-eight healthy participants were asked to simulate hypernasality in either an "errorless learning" condition (in which the possibility for errors was limited) or an "errorful learning"…

  1. Lattice Boltzmann modeling of directional wetting: comparing simulations to experiments.

    PubMed

    Jansen, H Patrick; Sotthewes, Kai; van Swigchem, Jeroen; Zandvliet, Harold J W; Kooij, E Stefan

    2013-07-01

    Lattice Boltzmann Modeling (LBM) simulations were performed on the dynamic behavior of liquid droplets on chemically striped patterned surfaces, ultimately with the aim to develop a predictive tool enabling reliable design of future experiments. The simulations accurately mimic experimental results, which have shown that water droplets on such surfaces adopt an elongated shape due to anisotropic preferential spreading. Details of the contact line motion such as advancing of the contact line in the direction perpendicular to the stripes exhibit pronounced similarities in experiments and simulations. The opposite of spreading, i.e., evaporation of water droplets, leads to a characteristic receding motion first in the direction parallel to the stripes, while the contact line remains pinned perpendicular to the stripes. Only when the aspect ratio is close to unity, the contact line also starts to recede in the perpendicular direction. Very similar behavior was observed in the LBM simulations. Finally, droplet movement can be induced by a gradient in surface wettability. LBM simulations show good semiquantitative agreement with experimental results of decanol droplets on a well-defined striped gradient, which move from high- to low-contact angle surfaces. Similarities and differences for all systems are described and discussed in terms of the predictive capabilities of LBM simulations to model direction wetting. PMID:23944550

  2. Comparisons of Single Drop Impact Simulations with Experiments

    NASA Astrophysics Data System (ADS)

    Medam, Krishna Teja

    As the size of electronic equipment is reduced, the ability to reject waste heat is also reduced due to smaller component surface areas, thereby affecting the component performance and finally leading to the damage of the component. Spray cooling offers a means to achieve high rates of heat transfer from microelectronic components and other high energy density devices. As a first step in investigating spray cooling, a single liquid drop impacting onto a thin liquid film was studied at isothermal conditions. 2D axisymmetric cases were simulated with ANSYS Fluent and 3D cases with OpenFOAM using the Volume of Fluid (VOF) model. The post processing of the results was performed in Surfer (Version 9) software in order to determine the liquid film thickness and then calculate the volume of the liquid under the cavity (sub-cavity liquid volume) as functions of time. These simulations agreed with the experimental data during the cavity formation phase, but did not closely match with the experiments during the refilling of the cavity in the majority of the cases. It was speculated that the discrepancies could be due to the three dimensional instabilities leading to droplet ejection from the crown during the retraction phase. These instabilities are omitted from the 2D simulations, and were not adequately resolved in the 3D simulations. For this reason, identical cases were simulated in 3D in OpenFOAM using the VOF model. The improved agreement with experiments obtained with the three dimensional simulations is discussed.

  3. Simulation model for the closed plant experiment facility of CEEF.

    PubMed

    Abe, Koichi; Ishikawa, Yoshio; Kibe, Seishiro; Nitta, Keiji

    2005-01-01

    The Closed Ecology Experiment Facilities (CEEF) is a testbed for Controlled Ecological Life Support Systems (CELSS) investigations. CEEF including the physico-chemical material regenerative system has been constructed for the experiments of material circulation among plants, breeding animals and crew of CEEF. Because CEEF is a complex system, an appropriate schedule for the operation must be prepared in advance. The CEEF behavioral Prediction System, CPS, that will help to confirm the operation schedule, is under development. CPS will simulate CEEFs behavior with data (conditions of equipments, quantity of materials in tanks, etc.) of CEEF and an operation schedule that will be made by the operation team everyday, before the schedule will be carried out. The result of the simulation will show whether the operation schedule is appropriate or not. In order to realize CPS, models of the simulation program that is installed in CPS must mirror the real facilities of CEEF. For the first step of development, a flexible algorithm of the simulation program was investigated. The next step was development of a replicate simulation model of the material circulation system for the Closed Plant Experiment Facility (CPEF) that is a part of CEEF. All the parts of a real material circulation system for CPEF are connected together and work as a complex mechanism. In the simulation model, the system was separated into 38 units according to its operational segmentation. In order to develop each model for its corresponding unit, specifications for the model were fixed based on the specifications of the real part. These models were put into a simulation model for the system. PMID:16175692

  4. Simulation model for the closed plant experiment facility of CEEF

    NASA Astrophysics Data System (ADS)

    Abe, Koichi; Ishikawa, Yoshio; Kibe, Seishiro; Nitta, Keiji

    The Closed Ecology Experiment Facilities (CEEF) is a testbed for Controlled Ecological Life Support Systems (CELSS) investigations. CEEF including the physico-chemical material regenerative system has been constructed for the experiments of material circulation among plants, breeding animals and crew of CEEF. Because CEEF is a complex system, an appropriate schedule for the operation must be prepared in advance. The CEEF behavioral Prediction System, CPS, that will help to confirm the operation schedule, is under development. CPS will simulate CEEFs behavior with data (conditions of equipments, quantity of materials in tanks, etc.) of CEEF and an operation schedule that will be made by the operation team everyday, before the schedule will be carried out. The result of the simulation will show whether the operation schedule is appropriate or not. In order to realize CPS, models of the simulation program that is installed in CPS must mirror the real facilities of CEEF. For the first step of development, a flexible algorithm of the simulation program was investigated. The next step was development of a replicate simulation model of the material circulation system for the Closed Plant Experiment Facility (CPEF) that is a part of CEEF. All the parts of a real material circulation system for CPEF are connected together and work as a complex mechanism. In the simulation model, the system was separated into 38 units according to its operational segmentation. In order to develop each model for its corresponding unit, specifications for the model were fixed based on the specifications of the real part. These models were put into a simulation model for the system.

  5. Simulation of Physical Experiments in Immersive Virtual Environments

    NASA Technical Reports Server (NTRS)

    Noor, Ahmed K.; Wasfy, Tamer M.

    2001-01-01

    An object-oriented event-driven immersive Virtual environment is described for the creation of virtual labs (VLs) for simulating physical experiments. Discussion focuses on a number of aspects of the VLs, including interface devices, software objects, and various applications. The VLs interface with output devices, including immersive stereoscopic screed(s) and stereo speakers; and a variety of input devices, including body tracking (head and hands), haptic gloves, wand, joystick, mouse, microphone, and keyboard. The VL incorporates the following types of primitive software objects: interface objects, support objects, geometric entities, and finite elements. Each object encapsulates a set of properties, methods, and events that define its behavior, appearance, and functions. A container object allows grouping of several objects. Applications of the VLs include viewing the results of the physical experiment, viewing a computer simulation of the physical experiment, simulation of the experiments procedure, computational steering, and remote control of the physical experiment. In addition, the VL can be used as a risk-free (safe) environment for training. The implementation of virtual structures testing machines, virtual wind tunnels, and a virtual acoustic testing facility is described.

  6. Physics potential of a long-baseline neutrino oscillation experiment using a J-PARC neutrino beam and Hyper-Kamiokande

    NASA Astrophysics Data System (ADS)

    Abe, K.; Aihara, H.; Andreopoulos, C.; Anghel, I.; Ariga, A.; Ariga, T.; Asfandiyarov, R.; Askins, M.; Back, J. J.; Ballett, P.; Barbi, M.; Barker, G. J.; Barr, G.; Bay, F.; Beltrame, P.; Berardi, V.; Bergevin, M.; Berkman, S.; Berry, T.; Bhadra, S.; Blaszczyk, F. d. M.; Blondel, A.; Bolognesi, S.; Boyd, S. B.; Bravar, A.; Bronner, C.; Cafagna, F. S.; Carminati, G.; Cartwright, S. L.; Catanesi, M. G.; Choi, K.; Choi, J. H.; Collazuol, G.; Cowan, G.; Cremonesi, L.; Davies, G.; De Rosa, G.; Densham, C.; Detwiler, J.; Dewhurst, D.; Di Lodovico, F.; Di Luise, S.; Drapier, O.; Emery, S.; Ereditato, A.; Fernández, P.; Feusels, T.; Finch, A.; Fitton, M.; Friend, M.; Fujii, Y.; Fukuda, Y.; Fukuda, D.; Galymov, V.; Ganezer, K.; Gonin, M.; Gumplinger, P.; Hadley, D. R.; Haegel, L.; Haesler, A.; Haga, Y.; Hartfiel, B.; Hartz, M.; Hayato, Y.; Hierholzer, M.; Hill, J.; Himmel, A.; Hirota, S.; Horiuchi, S.; Huang, K.; Ichikawa, A. K.; Iijima, T.; Ikeda, M.; Imber, J.; Inoue, K.; Insler, J.; Intonti, R. A.; Irvine, T.; Ishida, T.; Ishino, H.; Ishitsuka, M.; Itow, Y.; Izmaylov, A.; Jamieson, B.; Jang, H. I.; Jiang, M.; Joo, K. K.; Jung, C. K.; Kaboth, A.; Kajita, T.; Kameda, J.; Karadhzov, Y.; Katori, T.; Kearns, E.; Khabibullin, M.; Khotjantsev, A.; Kim, J. Y.; Kim, S. B.; Kishimoto, Y.; Kobayashi, T.; Koga, M.; Konaka, A.; Kormos, L. L.; Korzenev, A.; Koshio, Y.; Kropp, W. R.; Kudenko, Y.; Kutter, T.; Kuze, M.; Labarga, L.; Lagoda, J.; Laveder, M.; Lawe, M.; Learned, J. G.; Lim, I. T.; Lindner, T.; Longhin, A.; Ludovici, L.; Ma, W.; Magaletti, L.; Mahn, K.; Malek, M.; Mariani, C.; Marti, L.; Martin, J. F.; Martin, C.; Martins, P. P. J.; Mazzucato, E.; McCauley, N.; McFarland, K. S.; McGrew, C.; Mezzetto, M.; Minakata, H.; Minamino, A.; Mine, S.; Mineev, O.; Miura, M.; Monroe, J.; Mori, T.; Moriyama, S.; Mueller, T.; Muheim, F.; Nakahata, M.; Nakamura, K.; Nakaya, T.; Nakayama, S.; Needham, M.; Nicholls, T.; Nirkko, M.; Nishimura, Y.; Noah, E.; Nowak, J.; Nunokawa, H.; O'Keeffe, H. M.; Okajima, Y.; Okumura, K.; Oser, S. M.; O'Sullivan, E.; Ovsiannikova, T.; Owen, R. A.; Oyama, Y.; Pérez, J.; Pac, M. Y.; Palladino, V.; Palomino, J. L.; Paolone, V.; Payne, D.; Perevozchikov, O.; Perkin, J. D.; Pistillo, C.; Playfer, S.; Posiadala-Zezula, M.; Poutissou, J.-M.; Quilain, B.; Quinto, M.; Radicioni, E.; Ratoff, P. N.; Ravonel, M.; Rayner, M. A.; Redij, A.; Retiere, F.; Riccio, C.; Richard, E.; Rondio, E.; Rose, H. J.; Ross-Lonergan, M.; Rott, C.; Rountree, S. D.; Rubbia, A.; Sacco, R.; Sakuda, M.; Sanchez, M. C.; Scantamburlo, E.; Scholberg, K.; Scott, M.; Seiya, Y.; Sekiguchi, T.; Sekiya, H.; Shaikhiev, A.; Shimizu, I.; Shiozawa, M.; Short, S.; Sinnis, G.; Smy, M. B.; Sobczyk, J.; Sobel, H. W.; Stewart, T.; Stone, J. L.; Suda, Y.; Suzuki, Y.; Suzuki, A. T.; Svoboda, R.; Tacik, R.; Takeda, A.; Taketa, A.; Takeuchi, Y.; Tanaka, H. A.; Tanaka, H. K. M.; Tanaka, H.; Terri, R.; Thompson, L. F.; Thorpe, M.; Tobayama, S.; Tolich, N.; Tomura, T.; Touramanis, C.; Tsukamoto, T.; Tzanov, M.; Uchida, Y.; Vagins, M. R.; Vasseur, G.; Vogelaar, R. B.; Walter, C. W.; Wark, D.; Wascko, M. O.; Weber, A.; Wendell, R.; Wilkes, R. J.; Wilking, M. J.; Wilson, J. R.; Xin, T.; Yamamoto, K.; Yanagisawa, C.; Yano, T.; Yen, S.; Yershov, N.; Yokoyama, M.; Zito, M.

    2015-05-01

    Hyper-Kamiokande will be a next-generation underground water Cherenkov detector with a total (fiducial) mass of 0.99 (0.56) million metric tons, approximately 20 (25) times larger than that of Super-Kamiokande. One of the main goals of Hyper-Kamiokande is the study of CP asymmetry in the lepton sector using accelerator neutrino and anti-neutrino beams. In this paper, the physics potential of a long-baseline neutrino experiment using the Hyper-Kamiokande detector and a neutrino beam from the J-PARC proton synchrotron is presented. The analysis uses the framework and systematic uncertainties derived from the ongoing T2K experiment. With a total exposure of 7.5 MW × 10^7s integrated proton beam power (corresponding to 1.56 × 10^{22} protons on target with a 30 GeV proton beam) to a 2.5^circ off-axis neutrino beam, it is expected that the leptonic CP phase δ _{CP} can be determined to better than 19 degrees for all possible values of δ _{CP}, and CP violation can be established with a statistical significance of more than 3 σ (5 σ) for 76{%} (58{%}) of the {δ _{CP}} parameter space. Using both ν _e appearance and ν _μ disappearance data, the expected 1σ uncertainty of sin ^2θ _{23} is 0.015(0.006) for sin ^2θ _{23}=0.5(0.45).

  7. Three-dimensional simulations of Nova capsule implosion experiments

    SciTech Connect

    Marinak, M.M.; Tipton, R.E.; Landen, O.L.

    1995-11-01

    Capsule implosion experiments carried out on the Nova laser are simulated with the three-dimensional HYDRA radiation hydrodynamics code. Simulations of ordered near single mode perturbations indicate that structures which evolve into round spikes can penetrate farthest into the hot spot. Bubble-shaped perturbations can burn through the capsule shell fastest, however, causing even more damage. Simulations of a capsule with multimode perturbations shows spike amplitudes evolving in good agreement with a saturation model during the deceleration phase. The presence of sizable low mode asymmetry, caused either by drive asymmetry or perturbations in the capsule shell, can dramatically affect the manner in which spikes approach the center of the hot spot. Three-dimensional coupling between the low mode shell perturbations intrinsic to Nova capsules and the drive asymmetry brings the simulated yields into closer agreement with the experimental values.

  8. FLASH magnetohydrodynamic simulations of shock-generated magnetic field experiments

    NASA Astrophysics Data System (ADS)

    Tzeferacos, P.; Fatenejad, M.; Flocke, N.; Gregori, G.; Lamb, D. Q.; Lee, D.; Meinecke, J.; Scopatz, A.; Weide, K.

    2012-12-01

    We report the results of benchmark FLASH magnetohydrodynamic (MHD) simulations of experiments conducted by the University of Oxford High Energy Density Laboratory Astrophysics group and its collaborators at the Laboratoire pour l'Utilisation des Lasers Intenses (LULI). In these experiments, a long-pulse laser illuminates a target in a chamber filled with Argon gas, producing shock waves that generate magnetic fields via the Biermann battery mechanism. We first outline the implementation of 2D cylindrical geometry in the unsplit MHD solver in FLASH and present results of verification tests. We then describe the results of benchmark 2D cylindrical MHD simulations of the LULI experiments using FLASH that explore the impact of external fields along with the possibility of magnetic field amplification by turbulence that is associated with the shock waves and that is induced by a grid placed in the gas-filled chamber.

  9. Post Shot Simulations of NIF Convergent Ablator Experiments

    NASA Astrophysics Data System (ADS)

    Olson, R. E.; Meezan, N. B.; Hicks, D. G.; Landen, O. L.; Dewald, E. L.; Jones, O. S.; Langer, S. H.; Callahan, D. A.; Petrasso, R. D.; Zylstra, A. B.

    2012-10-01

    Post shot simulations of NIF convergent ablator experiments will be described. The experiments use a streaked radiograph of a backlit capsule implosion to measure the trajectory, velocity, remaining mass, and ablator rhoR and are an important component of the U. S. National Ignition Campaign. The integrated (capsule-in-hohlraum) post shot simulations use measured target parameters, measured laser input powers, measured time-resolved backscatter, and calculated cross-beam power transfer. The integrated calculations are post-processed to provide simulations of the key diagnostics, including: 1) Dante measurements of the hohlraum x-ray flux and spectrum; 2) streaked radiographs of the imploding ablator shell; 3) wedge range filter measurements of D-He3 proton output spectra; and 4) GXD images of the imploded core. The simulated diagnostics are compared to the experimental measurements to provide an assessment of the accuracy of the design code, to enhance understanding of the experiments, and to assist in choosing parameters for subsequent steps in the path towards optimal ignition capsule tuning.

  10. Simulations of Validation Platform Experiments by the PSI-Center

    NASA Astrophysics Data System (ADS)

    Nelson, B. A.; Akcay, C.; Glasser, A. H.; Hansen, C. J.; Jarboe, T. R.; Kim, C. C.; Marklin, G. J.; Milroy, R. D.; Shumlak, U.; Sovinec, C. R.; O'Bryan, J. B.; Held, E.; Ji, J.-Y.; Lukin, V. S.

    2012-10-01

    The Plasma Science and Innovation Center (PSI-Center - http://www.psicenter.org) assists collaborating validation platform experiments with extended MHD simulations. Collaborators include the Bellan Plasma Group (Caltech), CTH (Auburn U), FRX-L (Los Alamos National Laboratory), HIT-SI (U Wash - UW), LDX (M.I.T.), MST & Pegasus (U Wisc-Madison), PHD (UW), PFRC (PPPL), SSX (Swarthmore College), TCS (UW), and ZaP (UW). Modifications have been made to the NIMROD, HiFi, and PSI-Tet codes to specifically model these experiments, including mesh generation/refinement, appropriate boundary conditions (external fields, insulating BCs, etc.), and kinetic and neutral particle interactions. The PSI-Center is planning to add neutrals to NIMROD. When implemented in NIMROD, these results will be compared to the neutral particle physics in the 2D version of HiFi. Coaxial helicity injection BCs will be specified in HiFi to simulate the Caltech co-planar experiment, for verification with previous and ongoing NIMROD simulations. Results from these simulations, as well as an overview of the PSI-Center status will be presented.

  11. Processing biobased polymers using plasticizers: Numerical simulations versus experiments

    NASA Astrophysics Data System (ADS)

    Desplentere, Frederik; Cardon, Ludwig; Six, Wim; Erkoç, Mustafa

    2016-03-01

    In polymer processing, the use of biobased products shows lots of possibilities. Considering biobased materials, biodegradability is in most cases the most important issue. Next to this, bio based materials aimed at durable applications, are gaining interest. Within this research, the influence of plasticizers on the processing of the bio based material is investigated. This work is done for an extrusion grade of PLA, Natureworks PLA 2003D. Extrusion through a slit die equipped with pressure sensors is used to compare the experimental pressure values to numerical simulation results. Additional experimental data (temperature and pressure data along the extrusion screw and die are recorded) is generated on a dr. Collin Lab extruder producing a 25mm diameter tube. All these experimental data is used to indicate the appropriate functioning of the numerical simulation tool Virtual Extrusion Laboratory 6.7 for the simulation of both the industrial available extrusion grade PLA and the compound in which 15% of plasticizer is added. Adding the applied plasticizer, resulted in a 40% lower pressure drop over the extrusion die. The combination of different experiments allowed to fit the numerical simulation results closely to the experimental values. Based on this experience, it is shown that numerical simulations also can be used for modified bio based materials if appropriate material and process data are taken into account.

  12. Comparison of electron cloud simulation and experiments in the high-current experiment

    SciTech Connect

    Cohen, R.H.; Friedman, A.; Covo, M. Kireeff; Lund, S.M.; Molvik, A.W.; Bieniosek, F.M.; Seidl, P.A.; Vay, J.-L.; Verboncoeur, J.; Stoltz, P.; Veitzer, S.

    2004-08-27

    A set of experiments has been performed on the High-Current Experiment (HCX) facility at LBNL, in which the ion beam is allowed to collide with an end plate and thereby induce a copious supply of desorbed electrons. Through the use of combinations of biased and grounded electrodes positioned in between and downstream of the quadrupole magnets, the flow of electrons upstream into the magnets can be turned on or off. Properties of the resultant ion beam are measured under each condition. The experiment is modeled via a full three-dimensional, two species (electron and ion) particle simulation, as well as via reduced simulations (ions with appropriately chosen model electron cloud distributions, and a high-resolution simulation of the region adjacent to the end plate). The three-dimensional simulations are the first of their kind and the first to make use of a timestep-acceleration scheme that allows the electrons to be advanced with a timestep that is not small compared to the highest electron cyclotron period. The simulations reproduce qualitative aspects of the experiments, illustrate some unanticipated physical effects, and serve as an important demonstration of a developing simulation capability.

  13. Comparison of Electron Cloud Simulation and Experiments in the High-Current Experiment

    SciTech Connect

    Cohen, R; Friedman, A; Covo, M K; Lund, S; Molvik, A; Bieniosek, F; Seidl, P; Vay, J; Verboncoeur, J; Stoltz, P; Veitzer, S

    2004-10-07

    A set of experiments has been performed on the High-Current Experiment (HCX) facility at LBNL, in which the ion beam is allowed to collide with an end plate and thereby induce a copious supply of desorbed electrons. Through the use of combinations of biased and grounded electrodes positioned in between and downstream of the quadrupole magnets, the flow of electrons upstream into the magnets can be turned on or off. Properties of the resultant ion beam are measured under each condition. The experiment is modeled via a full three-dimensional, two species (electron and ion) particle simulation, as well as via reduced simulations (ions with appropriately chosen model electron cloud distributions, and a high-resolution simulation of the region adjacent to the end plate). The three-dimensional simulations are the first of their kind and the first to make use of a timestep-acceleration scheme that allows the electrons to be advanced with a timestep that is not small compared to the highest electron cyclotron period. The simulations reproduce qualitative aspects of the experiments, illustrate some unanticipated physical effects, and serve as an important demonstration of a developing simulation capability.

  14. CET exSim: mineral exploration experience via simulation

    NASA Astrophysics Data System (ADS)

    Wong, Jason C. 13Holden, Eun-Jung 1Kovesi, Peter 1McCuaig, T. Campbell 1Hronsky, Jon

    2013-08-01

    Undercover mineral exploration is a challenging task as it requires understanding of subsurface geology by relying heavily on remotely sensed (i.e. geophysical) data. Cost-effective exploration is essential in order to increase the chance of success using finite budgets. This requires effective decision-making in both the process of selecting the optimum data collection methods and in the process of achieving accuracy during subsequent interpretation. Traditionally, developing the skills, behaviour and practices of exploration decision-making requires many years of experience through working on exploration projects under various geological settings, commodities and levels of available resources. This implies long periods of sub-optimal exploration decision-making, before the necessary experience has been successfully obtained. To address this critical industry issue, our ongoing research focuses on the development of the unique and novel e-learning environment, exSim, which simulates exploration scenarios where users can test their strategies and learn the consequences of their choices. This simulator provides an engaging platform for self-learning and experimentation in exploration decision strategies, providing a means to build experience more effectively. The exSim environment also provides a unique platform on which numerous scenarios and situations (e.g. deposit styles) can be simulated, potentially allowing the user to become virtually familiarised with a broader scope of exploration practices. Harnessing the power of computer simulation, visualisation and an intuitive graphical user interface, the simulator provides a way to assess the user's exploration decisions and subsequent interpretations. In this paper, we present the prototype functionalities in exSim including: simulation of geophysical surveys, follow-up drill testing and interpretation assistive tools.

  15. Combustion-Powered Actuation for Dynamic Stall Suppression - Simulations and Low-Mach Experiments

    NASA Technical Reports Server (NTRS)

    Matalanis, Claude G.; Min, Byung-Young; Bowles, Patrick O.; Jee, Solkeun; Wake, Brian E.; Crittenden, Tom; Woo, George; Glezer, Ari

    2014-01-01

    An investigation on dynamic-stall suppression capabilities of combustion-powered actuation (COMPACT) applied to a tabbed VR-12 airfoil is presented. In the first section, results from computational fluid dynamics (CFD) simulations carried out at Mach numbers from 0.3 to 0.5 are presented. Several geometric parameters are varied including the slot chordwise location and angle. Actuation pulse amplitude, frequency, and timing are also varied. The simulations suggest that cycle-averaged lift increases of approximately 4% and 8% with respect to the baseline airfoil are possible at Mach numbers of 0.4 and 0.3 for deep and near-deep dynamic-stall conditions. In the second section, static-stall results from low-speed wind-tunnel experiments are presented. Low-speed experiments and high-speed CFD suggest that slots oriented tangential to the airfoil surface produce stronger benefits than slots oriented normal to the chordline. Low-speed experiments confirm that chordwise slot locations suitable for Mach 0.3-0.4 stall suppression (based on CFD) will also be effective at lower Mach numbers.

  16. Bose-Einstein Condensation: A Platform for Quantum Simulation Experiments

    NASA Astrophysics Data System (ADS)

    Yamamoto, Yoshihisa; Takahashi, Yoshiro

    Bose-Einstein condensation (BEC) of dilute atomic gases and dense exciton-polaritons provides unique experimental platforms for the simulation of quantum many-body systems in various trap and lattice structures. Atomic BEC is suitable for exploration of the thermal equilibrium and steady state properties of isolated many-body systems, while exciton-polariton BEC is suitable for study of the nonequilibrium and transient properties of open dissipative many-body systems. In this chapter, we will review the fundamental properties of these distinct Bose-Einstein condensates to provide a basis for later discussions of various quantum simulation experiments using cold atoms and exciton-polaritons.

  17. Engineering and simulation of life science Spacelab experiments

    NASA Technical Reports Server (NTRS)

    Bush, B.; Rummel, J.; Johnston, R. S.

    1977-01-01

    Approaches to the planning and realization of Spacelab life sciences experiments, which may involve as many as 16 Space Shuttle missions and 100 tests, are discussed. In particular, a Spacelab simulation program, designed to evaluate problems associated with the use of live animal specimens, the constraints imposed by zero gravity on equipment operation, training of investigators and data management, is described. The simulated facility approximates the hardware and support systems of a current European Space Agency Spacelab model. Preparations necessary for the experimental program, such as crew activity plans, payload documentation and inflight experimental procedures are developed; health problems of the crew, including human/animal microbial contamination, are also assessed.

  18. Numerical simulations of the QUELL experiment in SULTAN

    SciTech Connect

    Marinucci, C.

    1995-03-01

    The QUench Experiment on Long Length (QUELL) in the SULTAN Facility is planned to investigate the quench propagation and detection of a conductor with ITER relevant geometry and scaled performance. The objective of this study is to show the ability of QUELL to provide quench conditions relevant for ITER and to simulate the system performance, dealing in particular with the design aspects of the power supply, cryogenic system and heaters. The numerical analysis was performed with GANDALF - a 1-D code to analyze Dual Channel Cable-in-Conduit Conductors. A numerical convergence test and a comparison with another code and with analytical results have confirmed the validity of the simulations.

  19. Inverse Simulation of Field Infiltration Experiment Counting Preferential Flow

    NASA Astrophysics Data System (ADS)

    Zumr, David; Snehota, Michal; Nemcova, Renata; Dohnal, Michal; Cislerova, Milena

    2010-05-01

    The field tension and ponded infiltration experiments were conducted to monitor and describe irregularities of moisture propagation and to estimate the soil hydraulic properties (Distric Cambisol, Korkusova Hut, Sumava). On these soils the preferential pathways have been observed in several scales with the use of dye tracers, MRI and CT imaging. Preferential behavior was detected also during laboratory infiltration experiments. The flow irregularities are credited to variable air entrapment at the beginning of infiltrations. The field infiltration experiment was carried out in a shallow pit for a period of one day. The upper boundary condition was controlled by the tension disk infiltrometer, the propagation of a water front was monitored by two tensiometers installed in two depths below the infiltration disk. The propagation of saline solution front during ponded infiltration was visualized with high resolution electrical resistivity tomography (ERT). Infiltration experiments were monitored with TDR probes, tensiometers and ERT. Zones of preferential flow were determined through analyses of photographs taken during laboratory dye tracer infiltration experiments performed on undisturbed soil samples. Connectivity, volumetric ratio and spatial development of preferential pathways were evaluated as the necessary information for numerical simulations of flow using dual-permeability approach. 2D axisymetric numerical simulations were conducted to evaluate the results of the experiment. The parameter estimator PEST coupled with the simulation code S2D_DUAL (Vogel et al., 2000) were employed. Two different approaches were used: 1. Single-domain approach based on Richards' equation. 2. Dual-permeability approach based on two interacting water flow domains (matrix and preferential domains), each governed by one Richards' equation. Concerning the existence of preferential flow on investigated soil, the dual-permeability model gives a better picture of the flow regime. The

  20. Observing System Simulation Experiments for Fun and Profit

    NASA Technical Reports Server (NTRS)

    Prive, Nikki C.

    2015-01-01

    Observing System Simulation Experiments can be powerful tools for evaluating and exploring both the behavior of data assimilation systems and the potential impacts of future observing systems. With great power comes great responsibility - given a pure modeling framework, how can we be sure our results are meaningful? The challenges and pitfalls of OSSE calibration and validation will be addressed, as well as issues of incestuousness, selection of appropriate metrics, and experiment design. The use of idealized observational networks to investigate theoretical ideas in a fully complex modeling framework will also be discussed

  1. Simulations of silicon vertex tracker for star experiment at RHIC

    SciTech Connect

    Odyniec, G.; Cebra, D.; Christie, W.; Naudet, C.; Schroeder, L.; Wilson, W.; Liko, D.; Cramer, J.; Prindle, D.; Trainor, T.; Braithwaite, W.

    1991-12-31

    The first computer simulations to optimize the Silicon Vertex Tracker (SVT) designed for the STAR experiment at RHIC are presented. The physics goals and the expected complexity of the events at RHIC dictate the design of a tracking system for the STAR experiment. The proposed tracking system will consist of a silicon vertex tracker (SVT) to locate the primary interaction and secondary decay vertices and to improve the momentum resolution, and a time projection chamber (TPC), positioned inside a solenoidal magnet, for continuous tracking.

  2. Simulation studies of plasma lens experiments at Daresbury laboratory

    NASA Astrophysics Data System (ADS)

    Hanahoe, K.; Mete, O.; Xia, G.; Angal-Kalinin, D.; Jones, J.; Smith, J.

    2016-03-01

    Experiments are planned to study plasma lensing using the VELA and CLARA Front End accelerators at Daresbury Laboratory. This paper presents results of 2-dimensional particle-in-cell simulations of the proposed experiments. The variation in focusing strength and emittance growth with beam and plasma parameters are studied in the overdense (plasma density much greater than bunch density) regime for the VELA beam. The effect of spherical and longitudinal aberrations on the beam emittance was estimated through numerical and theoretical studies. Simulation results show that a focusing strength equivalent to a magnetic field gradient of 10 T m-1 can be achieved using VELA, and a gradient of 247 T m-1 can be achieved using CLARA Front End.

  3. Short Rayleigh length free electron laser: Experiments and simulations

    SciTech Connect

    Crooker, P.P.; Colson, William; Blau, Joe; Burggraff, D.; Sans Aguilar, J.; Benson, Stephen; Neil, George; Michelle D. Shinn; Evtushenko, Pavel

    2008-09-01

    DOI: http://dx.doi.org/10.1103/PhysRevSTAB.11.090701
    We report experiments at Jefferson National Accelerator Facility (Jlab) and computer simulations performed at the Naval Postgraduate School (NPS) designed to probe the small Rayleigh length regime. We compare the gain, power, and sensitivity to mirror and electron beam misalignments as a function of decreasing Rayleigh length. The agreement is quite good, with experiments and simulations showing comparable trends as the Rayleigh length is decreased. In particular, we find that the gain and power do not decrease substantially at short Rayleigh length, contrary to a common Gaussian-mode filling factor argument. Within currently achievable alignment tolerances, the gain and power are still acceptable for FEL operation.

  4. Bringing history to life: simulating landmark experiments in psychology.

    PubMed

    Boynton, David M; Smith, Laurence D

    2006-05-01

    The course in history of psychology can be challenging for students, many of whom enter it with little background in history and faced with unfamiliar names and concepts. The sheer volume of material can encourage passive memorization unless efforts are made to increase student involvement. As part of a trend toward experiential history, historians of science have begun to supplement their lectures with demonstrations of classic physics experiments as a way to bring the history of science to life. Here, the authors report on computer simulations of five landmark experiments from early experimental psychology in the areas of reaction time, span of attention, and apparent motion. The simulations are designed not only to permit hands-on replication of historically important results but also to reproduce the experimental procedures closely enough that students can gain a feel for the nature of early research and the psychological processes being studied. PMID:17152604

  5. Simulations of ICC Experiments by the PSI-Center

    NASA Astrophysics Data System (ADS)

    Nelson, Brian; Glasser, A. H.; Jarboe, T. R.; Kim, C. C.; Marklin, G. J.; Lowrie, W.; Meier, E. T.; Milroy, R. D.; Shumlak, U.; Sovinec, C. R.; O'Bryan, J. B.; Held, E.; Ji, J.-Y.; Lukin, V. S.

    2011-10-01

    The Plasma Science and Innovation Center (PSI-Center - http://www.psicenter.org) assists collaborating innovative confinement concept (ICC) experiments with extended MHD simulations. Collaborators include the Bellan Plasma Group (Caltech), CTH (Auburn U), FRX-L (Los Alamos National Laboratory), HIT-SI (U Wash - UW), LDX (M.I.T.), MST & Pegasus (U Wisc-Madison), PHD (UW), PFRC (PPPL), SSX (Swarthmore College), TCS (UW), and ZaP (UW). Modifications have been made to the NIMROD, HiFi, and PSI-Tet codes to specifically model these ICC experiments, including mesh generation/refinement, appropriate boundary conditions (external fields, insulating BCs, etc.), and kinetic and neutral particle interactions. Interfaces of these codes to the powerful 3-D visualization program, VisIt (http://www.llnl.gov/visit) have been developed and implemented. Results from these simulations, as well as an overview of the Interfacing Group status will be presented.

  6. The Effect of Hematocrit on Platelet Adhesion: Experiments and Simulations.

    PubMed

    Spann, Andrew P; Campbell, James E; Fitzgibbon, Sean R; Rodriguez, Armando; Cap, Andrew P; Blackbourne, Lorne H; Shaqfeh, Eric S G

    2016-08-01

    The volume fraction of red blood cells (RBCs) in a capillary affects the degree to which platelets are promoted to marginate to near a vessel wall and form blood clots. In this work we investigate the relationship between RBC hematocrit and platelet adhesion activity. We perform experiments flowing blood samples through a microfluidic channel coated with type 1 collagen and observe the rate at which platelets adhere to the wall. We compare these results with three-dimensional boundary integral simulations of a suspension of RBCs and platelets in a periodic channel where platelets can adhere to the wall. In both cases, we find that the rate of platelet adhesion varies greatly with the RBC hematocrit. We observe that the relative decrease in platelet activity as hematocrit falls shows a similar profile for simulation and experiment. PMID:27508441

  7. Virtual Reality Simulation of the International Space Welding Experiment

    NASA Technical Reports Server (NTRS)

    Phillips, James A.

    1996-01-01

    Virtual Reality (VR) is a set of breakthrough technologies that allow a human being to enter and fully experience a 3-dimensional, computer simulated environment. A true virtual reality experience meets three criteria: (1) It involves 3-dimensional computer graphics; (2) It includes real-time feedback and response to user actions; and (3) It must provide a sense of immersion. Good examples of a virtual reality simulator are the flight simulators used by all branches of the military to train pilots for combat in high performance jet fighters. The fidelity of such simulators is extremely high -- but so is the price tag, typically millions of dollars. Virtual reality teaching and training methods are manifestly effective, and we have therefore implemented a VR trainer for the International Space Welding Experiment. My role in the development of the ISWE trainer consisted of the following: (1) created texture-mapped models of the ISWE's rotating sample drum, technology block, tool stowage assembly, sliding foot restraint, and control panel; (2) developed C code for control panel button selection and rotation of the sample drum; (3) In collaboration with Tim Clark (Antares Virtual Reality Systems), developed a serial interface box for the PC and the SGI Indigo so that external control devices, similar to ones actually used on the ISWE, could be used to control virtual objects in the ISWE simulation; (4) In collaboration with Peter Wang (SFFP) and Mark Blasingame (Boeing), established the interference characteristics of the VIM 1000 head-mounted-display and tested software filters to correct the problem; (5) In collaboration with Peter Wang and Mark Blasingame, established software and procedures for interfacing the VPL DataGlove and the Polhemus 6DOF position sensors to the SGI Indigo serial ports. The majority of the ISWE modeling effort was conducted on a PC-based VR Workstation, described below.

  8. Dynamics of cell aggregates fusion: Experiments and simulations

    NASA Astrophysics Data System (ADS)

    Thomas, Gilberto L.; Mironov, Vladimir; Nagy-Mehez, Agnes; Mombach, José C. M.

    2014-02-01

    Fusion of cell tissues is an ubiquitous phenomenon and has important technological applications including tissue biofabrication. In this work we present experimental results of aggregates fusion using adipose derived stem cells (ADSC) and a three dimensional computer simulation of the process using the cellular Potts model with aggregates reaching 10,000 cells. We consider fusion of round aggregates and monitor the dimensionless neck area of contact between the two aggregates to characterize the process, as done for the coalescence of liquid droplets and polymers. Both experiments and simulations show that the evolution of this quantity obeys a power law in time. We also study quantitatively individual cell motion with the simulation and it corresponds to an anomalous diffusion.

  9. Students' experiences of learning manual clinical skills through simulation.

    PubMed

    Johannesson, Eva; Silén, Charlotte; Kvist, Joanna; Hult, Håkan

    2013-03-01

    Learning manual skills is a fundamental part of health care education, and motor, sensory and cognitive learning processes are essential aspects of professional development. Simulator training has been shown to enhance factors that facilitate motor and cognitive learning. The present study aimed to investigate the students' experiences and thoughts about their learning through simulation skills training. The study was designed for an educational setting at a clinical skills centre. Ten third-year undergraduate nursing students performed urethral catheterisation, using the virtual reality simulator UrecathVision™, which has haptic properties. The students practised in pairs. Each session was videotaped and the video was used to stimulate recall in subsequent interviews. The interviews were analysed using qualitative content analysis. The analysis from interviews resulted in three themes: what the students learn, how the students learn, and the simulator's contribution to the students' learning. Students learned manual skills, how to perform the procedure, and professional behaviour. They learned by preparing, watching, practising and reflecting. The simulator contributed by providing opportunities for students to prepare for the skills training, to see anatomical structures, to feel resistance, and to become aware of their own performance ability. The findings show that the students related the task to previous experiences, used sensory information, tested themselves and practised techniques in a hands-on fashion, and reflected in and on action. The simulator was seen as a facilitator to learning the manual skills. The study design, with students working in pairs combined with video recording, was found to enhance opportunities for reflection. PMID:22395307

  10. Dynamic materials response at multiscales: Experiments and simulations

    NASA Astrophysics Data System (ADS)

    Luo, Sheng-Nian

    One of the grand challenges in materials physics is dynamic responses to impulsive loading, including shock waves, radiation, and pulsed fields, due to their highly transient nature and extremely complex microstructure effects. Dynamic responses, such as plasticity, damage, cavitation, phase changes, and chemical reactions, are inherently multiscale and heavily dependent on microstructure. One has to resort to a suite of tools, including experiments, modeling and simulations, and theory. However, the gaps in spatial or temporal scales between experiments and simulations are still wide, while cross-scale theories are still in early development. To this end, we exploit large-scale molecular dynamics simulations, electron microscopy, and ultrafast synchrotron X-ray imaging and scattering, to probe materials response at length scales ranging from lattice to micron, and time scales, from picosecond to second. For examples, simultaneous, high-speed, X-ray imaging (mesoscale strain-field mapping) and diffraction measurements along with macroscopic measurements have been achieved. Based on classical nucleation theory and large-scale molecular dynamics simulations, we demonstrate the equivalence between length and time scales for nucleation events, which provides a framework to bridge different scales. Certainly, advancing multiscale science requires sustained, concerted, experimental, modeling and theoretical efforts. We have benefited from the colleagues at the Advanced Photon Source, and the Peac Institute of Multiscales Sciences.

  11. Information-Based Evacuation Experiment and its Cellular Automaton Simulation

    NASA Astrophysics Data System (ADS)

    Yang, Lizhong; Liu, Shaobo; Li, Jian; Zhu, Kongjin; Fang, Tingyong

    The evacuation process under emergency is studied by means of experiments and simulations, focusing on the influence of the environment information. A revised cellular automaton model in which environment information is considered as "static information" (building structure, spatial distance, etc.) and "dynamic information" (sounds of fire alarm, etc.) is introduced. Two scenarios, including evacuation with and without visibility in a classroom, are studied to investigate the different influence of the two kinds of information on human behavior. The experimental and simulation results demonstrate that: (1) to intensify the spatial distance information can reduce the evacuation time; (2) the spatial distance is not the only decisive factor especially in evacuation without visibility because the sound information, which is ignorable in evacuation with visibility, is playing a more important role under this condition; (3) the intensity of static information can reflect evacuees' familiarity of the environment; (4) the model can reproduce the experiments well, and the simulation method is useful for further study of the crowd movement simulation.

  12. Simulation of fabrication variations in supernova hydrodynamics experiments

    NASA Astrophysics Data System (ADS)

    Budde, A.; Drake, R. P.; Kuranz, C. C.; Grosskopf, M. J.; Plewa, T.; Hearn, N. C.

    2010-06-01

    Recent experiments at the Omega laser facility have used ˜4.5 kJ of energy to create a blast wave similar to the one that occurs in a core-collapse supernova. In the experiment, the blast wave crosses an interface with a drop in density similar to the He-H interface in a supernova, which induces the growth of a machined perturbation on the interface surface due to the Rayleigh-Taylor instability. These experiments have exhibited different morphology than our simulations predict. It has been hypothesized that such differences may be the result of unintended structures created in the target fabrication process. We have used 2D Cartesian simulations to model such fabrication variations using a branch of the hydrodynamic code FLASH. We have studied the convergence of these numerical models and developed analysis techniques to gauge and compare the impact each variation has on numerical results. In addition to this, we have implemented and verified a new viscosity package for our code. These accomplishments have allowed us to perform a thorough analysis of the effects that such fabrication variations have on our results through the use of numerical simulations.

  13. LMFBR source term experiments in the Fuel Aerosol Simulant Test (FAST) facility

    SciTech Connect

    Petrykowski, J.C.; Longest, A.W.

    1985-01-01

    The transport of uranium dioxide (UO/sub 2/) aerosol through liquid sodium was studied in a series of ten experiments in the Fuel Aerosol Simulant Test (FAST) facility at Oak Ridge National Laboratory (ORNL). The experiments were designed to provide a mechanistic basis for evaluating the radiological source term associated with a postulated, energetic core disruptive accident (CDA) in a liquid metal fast breeder reactor (LMFBR). Aerosol was generated by capacitor discharge vaporization of UO/sub 2/ pellets which were submerged in a sodium pool under an argon cover gas. Measurements of the pool and cover gas pressures were used to study the transport of aerosol contained by vapor bubbles within the pool. Samples of cover gas were filtered to determine the quantity of aerosol released from the pool. The depth at which the aerosol was generated was found to be the most critical parameter affecting release. The largest release was observed in the baseline experiment where the sample was vaporized above the sodium pool. In the nine ''undersodium'' experiments aerosol was generated beneath the surface of the pool at depths varying from 30 to 1060 mm. The mass of aerosol released from the pool was found to be a very small fraction of the original specimen. It appears that the bulk of aerosol was contained by bubbles which collapsed within the pool. 18 refs., 11 figs., 4 tabs.

  14. Simulation experiences of paramedic students: a cross-cultural examination

    PubMed Central

    Williams, Brett; Abel, Chloe; Khasawneh, Eihab; Ross, Linda; Levett-Jones, Tracy

    2016-01-01

    Background Simulation-based education is an important part of paramedic education and training. While accessing clinical placements that are adequate in quality and quantity continues to be challenging, simulation is being recognized by paramedic academics as a potential alternative. Examining students’ satisfaction of simulation, particularly cross-culturally is therefore important in providing feedback to academic teaching staff and the international paramedic community. Objective This study aimed to compare simulation satisfaction among paramedic students from universities in Australia and Jordan. Methods A cross-sectional study using a paper-based English version of the Satisfaction with Simulation Experience Scale was administered to paramedic students from all year levels. Results A total of 511 students participated in this study; 306 students (60%) from Australia (Monash University) and 205 students (40%) from Jordan (Jordan University of Science and Technology). There were statistically significant differences with large effect size noted in all three original factors between Australian and Jordanian students: debrief and feedback (mean =38.66 vs mean =34.15; P<0.001; d=0.86), clinical reasoning (mean =21.32 vs mean =18.28; P<0.001; d=0.90), and clinical learning (mean =17.59 vs mean =15.47; P<0.001; d=1.12). Conclusion This study has demonstrated that simulation education is generally well received by students in Australia and Jordan although Australian students reported having higher satisfaction levels then their Jordanian counterparts. These results provide important data for paramedic educators involved in simulation-based education and training in Australia and Jordan and pave the way for other cross-cultural examinations to be explored. PMID:27051332

  15. Astrophysical Jets as Hypersonic Buckshot: Laboratory Experiments and Simulations

    NASA Astrophysics Data System (ADS)

    Frank, A.; Ciardi, A.; Yirak, K.; Lebedev, S.

    2009-08-01

    Herbig-Haro (HH) jets are commonly thought of as homogeneous beams of plasma traveling at hypersonic velocities. Structure within jet beams is often attributed to periodic or ``pulsed'' variations of conditions at the jet source. In this contribution we offer an alternative to ``pulsed'' models of protostellar jets. Using direct numerical simulations and laboratory experiments we explore the possibility that jets are chains of sub-radial clumps propagating through a moving inter-clump medium. Our simulations explore an idealization of this scenario by injecting small (r < r_{jet}), dense (rho > rho_{jet}) spheres embedded in an otherwise smooth inter-clump jet flow. The spheres are initialized with velocities differing from the jet velocity by ˜ 15%. We find the consequences of shifting from homogeneous to heterogeneous flows are significant as clumps interact with each other and with the inter-clump medium in a variety of ways. We also present new experiments that, for the first time, directly address issues of magnetized astrophysical jets. Our experiments explore the propagation and stability of super-magnetosonic, radiatively cooled, and magnetically dominated bubbles with internal, narrow jets. The results are scalable to astrophysical environments via the similarity of dimensionless numbers controlling the dynamics in both settings. These experiments show the jets are subject to kink mode instabilities which quickly fragment the jet into narrow chains of hypersonic knots, providing support for the ``clumpy jet'' paradigm.

  16. Dynamics and control simulation of the Spacelab Experiment Pointing Mount

    NASA Technical Reports Server (NTRS)

    Marsh, E. L.; Ward, R. S.

    1977-01-01

    Computer simulations were developed to evaluate the performance of four Experiment Pointing Mounts (EPM) being considered for Spacelab experiments in the 1980-1990 time frame. The system modeled compromises a multibody system consisting of the shuttle, a mechanical isolation device, the EPM, celestial and inertial sensors, bearings, gimbal torque motors and associated nonlinearities, the experiment payload, and control and estimator algorithms. Each mount was subjected to a common disturbance (shuttle vernier thruster firing and man push off) and command (stellar pointing or solar raster scan) input. The fundamental limitation common to all mounts was found to be sensor noise. System dynamics and hardware nonlinearities have secondary effects on pointing performance for sufficiently high bandwidth.

  17. DSMC Simulations of Hypersonic Flows and Comparison With Experiments

    NASA Technical Reports Server (NTRS)

    Moss, James N.; Bird, Graeme A.; Markelov, Gennady N.

    2004-01-01

    This paper presents computational results obtained with the direct simulation Monte Carlo (DSMC) method for several biconic test cases in which shock interactions and flow separation-reattachment are key features of the flow. Recent ground-based experiments have been performed for several biconic configurations, and surface heating rate and pressure measurements have been proposed for code validation studies. The present focus is to expand on the current validating activities for a relatively new DSMC code called DS2V that Bird (second author) has developed. Comparisons with experiments and other computations help clarify the agreement currently being achieved between computations and experiments and to identify the range of measurement variability of the proposed validation data when benchmarked with respect to the current computations. For the test cases with significant vibrational nonequilibrium, the effect of the vibrational energy surface accommodation on heating and other quantities is demonstrated.

  18. Computer simulation models are implementable as replacements for animal experiments.

    PubMed

    Badyal, Dinesh K; Modgill, Vikas; Kaur, Jasleen

    2009-04-01

    It has become increasingly difficult to perform animal experiments, because of issues related to the procurement of animals, and strict regulations and ethical issues related to their use. As a result, it is felt that the teaching of pharmacology should be more clinically oriented and that unnecessary animal experimentation should be avoided. Although a number of computer simulation models (CSMs) are available, they are not being widely used. Interactive demonstrations were conducted to encourage the departmental faculty to use CSMs. Four different animal experiments were selected, that dealt with actions of autonomic drugs. The students observed demonstrations of animal experiments involving conventional methods and the use of CSMs. This was followed by hands-on experience of the same experiment, but using CSMs in small groups, instead of hands-on experience with the animal procedures. Test scores and feedback showed that there was better understanding of the mechanisms of action of the drugs, gained in a shorter time. The majority of the students found the teaching programme used to be good to excellent. CSMs can be used repeatedly and independently by students, and this avoids unnecessary experimentation and also causing pain and trauma to animals. The CSM programme can be implemented in existing teaching schedules for pharmacology undergraduate teaching with basic infrastructure support, and is readily adaptable for use by other institutes. PMID:19453215

  19. Simulation and analyses of the aeroassist flight experiment attitude update method

    NASA Technical Reports Server (NTRS)

    Carpenter, J. R.

    1991-01-01

    A method which will be used to update the alignment of the Aeroassist Flight Experiment's Inertial Measuring Unit is simulated and analyzed. This method, the Star Line Maneuver, uses measurements from the Space Shuttle Orbiter star trackers along with an extended Kalman filter to estimate a correction to the attitude quaternion maintained by an Inertial Measuring Unit in the Orbiter's payload bay. This quaternion is corrupted by on-orbit bending of the Orbiter payload bay with respect to the Orbiter navigation base, which is incorporated into the payload quaternion when it is initialized via a direct transfer of the Orbiter attitude state. The method of updating this quaternion is examined through verification of baseline cases and Monte Carlo analysis using a simplified simulation, The simulation uses nominal state dynamics and measurement models from the Kalman filter as its real world models, and is programmed on Microvax minicomputer using Matlab, and interactive matrix analysis tool. Results are presented which confirm and augment previous performance studies, thereby enhancing confidence in the Star Line Maneuver design methodology.

  20. Engineering and simulation of life sciences Spacelab experiments

    NASA Technical Reports Server (NTRS)

    Johnston, R. S.; Bush, W. H. Jr; Rummel, J. A.; Alexander, W. C.

    1979-01-01

    The third in a series of Spacelab Mission Development tests was conducted at the Johnson (correction of Johnston) Space Center as a part of the development of Life Sciences experiments for the Space Shuttle era. The latest test was a joint effort of the Ames Research and Johnson Space Centers and utilized animals and men for study. The basic objective of this test was to evaluate the operational concepts planned for the Space Shuttle life science payloads program. A three-man crew (Mission Specialist and two Payload Specialists) conducted 26 experiments and 12 operational tests, which were selected for this 7-day mission simulation. The crew lived on board a simulated Orbiter/Spacelab mockup 24 hr a day. The Orbiter section contained the mid deck crew quarters area, complete with sleeping, galley and waste management provisions. The Spacelab was identical in geometry to the European Space Agency Spacelab design, complete with removable rack sections and stowage provisions. Communications between the crewmen and support personnel were configured and controlled as currently planned for operational shuttle flights. For this test a Science Operations Remote Center was manned at the Ames Research Center and was managed by simulated Mission Control and Payload Operation Control Centers at the Johnson Space Center. This paper presents the test objectives, description of the facilities and test program, and the results of this test.

  1. PSI-Center Simulations of Validation Platform Experiments

    NASA Astrophysics Data System (ADS)

    Nelson, B. A.; Akcay, C.; Glasser, A. H.; Hansen, C. J.; Jarboe, T. R.; Marklin, G. J.; Milroy, R. D.; Morgan, K. D.; Norgaard, P. C.; Shumlak, U.; Victor, B. S.; Sovinec, C. R.; O'Bryan, J. B.; Held, E. D.; Ji, J.-Y.; Lukin, V. S.

    2013-10-01

    The Plasma Science and Innovation Center (PSI-Center - http://www.psicenter.org) supports collaborating validation platform experiments with extended MHD simulations. Collaborators include the Bellan Plasma Group (Caltech), CTH (Auburn U), FRX-L (Los Alamos National Laboratory), HIT-SI (U Wash - UW), LTX (PPPL), MAST (Culham), Pegasus (U Wisc-Madison), PHD/ELF (UW/MSNW), SSX (Swarthmore College), TCSU (UW), and ZaP/ZaP-HD (UW). Modifications have been made to the NIMROD, HiFi, and PSI-Tet codes to specifically model these experiments, including mesh generation/refinement, non-local closures, appropriate boundary conditions (external fields, insulating BCs, etc.), and kinetic and neutral particle interactions. The PSI-Center is exploring application of validation metrics between experimental data and simulations results. Biorthogonal decomposition is proving to be a powerful method to compare global temporal and spatial structures for validation. Results from these simulation and validation studies, as well as an overview of the PSI-Center status will be presented.

  2. A natural experiment opportunity in two low-income urban food desert communities: research design, community engagement methods, and baseline results.

    PubMed

    Dubowitz, Tamara; Ncube, Collette; Leuschner, Kristin; Tharp-Gilliam, Shannah

    2015-04-01

    A growing body of evidence has highlighted an association between a lack of access to nutritious, affordable food (e.g., through full-service grocery stores [FSGs]), poor diet, and increased risk for obesity. In response, there has been growing interest among policy makers in encouraging the siting of supermarkets in "food deserts," that is, low-income geographic areas with low access to healthy food options. However, there is limited research to evaluate the impact of such efforts, and most studies to date have been cross-sectional. The Pittsburgh Hill/Homewood Research on Eating, Shopping, and Health (PHRESH) is a longitudinal quasi-experimental study of a dramatic change (i.e., a new FSG) in the food landscape of a low-income, predominantly Black neighborhood. The study is following a stratified random sample of households (n = 1,372), and all food venues (n = 60) in both intervention and control neighborhoods, and the most frequently reported food shopping venues outside both neighborhoods. This article describes the study design and community-based methodology, which focused simultaneously on the conduct of scientifically rigorous research and the development and maintenance of trust and buy-in from the involved neighborhoods. Early results have begun to define markers for success in creating a natural experiment, including strong community engagement. Baseline data show that the vast majority of residents already shop at a FSG and do not shop at the nearest one. Follow-up data collection will help determine whether and how a new FSG may change behaviors and may point to the need for additional interventions beyond new FSGs alone. PMID:25829122

  3. Modeling, simulation, and experiments of coating growth on nanofibers

    SciTech Connect

    Clemons, C. B.; Hamrick, P.; Heminger, J.; Kreider, K. L.; Young, G. W.; Buldum, A.; Evans, E.; Zhang, G.

    2008-02-15

    This work is a comparison of modeling and simulation results with experiments for an integrated experimental/modeling investigation of a procedure to coat nanofibers and core-clad nanostructures with thin film materials using plasma enhanced physical vapor deposition. In the experimental effort, electrospun polymer nanofibers are coated with metallic materials under different operating conditions to observe changes in the coating morphology. The modeling effort focuses on linking simple models at the reactor level, nanofiber level and atomic level to form a comprehensive model. The comprehensive model leads to the definition of an evolution equation for the coating free surface around an isolated nanofiber. This evolution equation was previously derived and solved under conditions of a nearly circular coating, with a concentration field that was only radially dependent and that was independent of the location of the coating free surface. These assumptions permitted the development of analytical expressions for the concentration field. The present work does not impose the above-mentioned conditions and considers numerical simulations of the concentration field that couple with level set simulations of the evolution equation for the coating free surface. Further, the cases of coating an isolated fiber as well as a multiple fiber mat are considered. Simulation results are compared with experimental results as the reactor pressure and power, as well as the nanofiber mat porosity, are varied.

  4. Non-equilibrium Warm Dense Gold: Experiments and Simulations

    NASA Astrophysics Data System (ADS)

    Ng, Andrew

    2015-11-01

    This talk is an overview of a series of studies of non-equilibrium Warm Dense Matter using a broad range of measured properties of a single material, namely Au, as comprehensive benchmarks for theory. The measurements are made in fs-laser pump-probe experiments. For understanding lattice stability, our investigation reveals a solid phase at high energy density. This leads to the calculation of lattice dynamics using MD simulations and phonon hardening in DFT-MD simulations. For understanding electron transport in two-temperature states, AC conductivity is used to evaluate DFT-MD and Kubo-Greenwood calculations while DC conductivity is used to test Ziman calculations in a DFT average atom model. The electron density is also used to assess electronic structure calculations in DFT simulations. In our latest study of electron kinetics in states with a non-Fermi-Dirac distribution, three-body recombination is found to have a significant effect on electron thermalizaiton time. This is driving an effort to develop electron kinetics simulations using the Boltzmann equation method.

  5. Extending a Flight Management Computer for Simulation and Flight Experiments

    NASA Technical Reports Server (NTRS)

    Madden, Michael M.; Sugden, Paul C.

    2005-01-01

    In modern transport aircraft, the flight management computer (FMC) has evolved from a flight planning aid to an important hub for pilot information and origin-to-destination optimization of flight performance. Current trends indicate increasing roles of the FMC in aviation safety, aviation security, increasing airport capacity, and improving environmental impact from aircraft. Related research conducted at the Langley Research Center (LaRC) often requires functional extension of a modern, full-featured FMC. Ideally, transport simulations would include an FMC simulation that could be tailored and extended for experiments. However, due to the complexity of a modern FMC, a large investment (millions of dollars over several years) and scarce domain knowledge are needed to create such a simulation for transport aircraft. As an intermediate alternative, the Flight Research Services Directorate (FRSD) at LaRC created a set of reusable software products to extend flight management functionality upstream of a Boeing-757 FMC, transparently simulating or sharing its operator interfaces. The paper details the design of these products and highlights their use on NASA projects.

  6. Simulated performance of the calorimetric electron telescope (CALET) experiment

    NASA Astrophysics Data System (ADS)

    Akaike, Y.; Taira, K.; Kasahara, K.; Torii, S.; Shimizu, Y.; Yoshida, K.; CALET Collaboration

    2010-03-01

    CALET is a detector planned to be on-board the Japanese Experiment Module Exposed Facility (JEM-EF) of the International Space Station. The CALET mission aims at revealing unsolved problems in high energy phenomena of the Universe by carrying out a precise measurement of the high energy electrons in 1 GeV-20 TeV, the gamma-rays in 20 MeV to a few TeV and the nuclei in a few 10 GeV-1000 TeV. The main detector is composed of imaging calorimeter (IMC), total absorption calorimeter (TASC), silicon pixel array (SIA) and anti-coincidence detector (ACD) to detect various kinds of particles in very wide energy range. The total absorber thickness is 31 radiation lengths for electromagnetic particles and 1.4 interaction mean free paths for protons. Monte Carlo simulation study has been carried out for optimization of the detector performance in observing each kind of particles. We obtained following performance about the observation of very high energy (>100 GeV) electrons, which is a main target of the CALET experiment: (1) Effective geometrical factor is about 7000 cm2 sr. (2) Energy resolution is better than a few %. (3) Angular resolution is better than 0.1°. (4) Proton rejection power is ˜105 with the electron detection efficiency better than 95%. We also present the simulated performance of the CALET experiment in observing other particles.

  7. Recent Observing System Simulation Experiments at the NASA DAO

    NASA Technical Reports Server (NTRS)

    Atlas, Robert; Emmitt, G. David; Terry, Joseph; Brin, Eugenia; Ardizzone, Joseph; Jusem, Juan Carlos; Bungato, Dennis

    2002-01-01

    Since the advent of meteorological satellites in the 1960's, numerous experiments have been conducted in order t o evaluate the impact of these and other data on atmospheric analysis and prediction. Such studies have included both OSE'S (Observing System Experiments) and OSSE's (Observing System Simulation Experiments). The OSE's were conducted to evaluate the impact of specific observations or classes of observations on analyses and forecasts. Such experiments have been performed for selected types of conventional data and for various satellite data sets as they became avail- able. (See for example the 1989 ECMWF/EUMETSAT workshop proceedings on "The use of satellite data in operational numerical weather prediction" and the references contained therein.) The OSSE's were con- ducted to evaluate the potential for future observing systems to improve Numerical Weather Prediction (NWP) and to plan for the Global Weather Experiment and more recently for EOS. In addition, OSSE's have been run t o evaluate trade-offs in the design of observing systems and observing net-works, and to test new methodology for data assimilation.

  8. Gyrokinetic Simulation of Global Turbulent Transport Properties in Tokamak Experiments

    SciTech Connect

    Wang, W.X.; Lin, Z.; Tang, W.M.; Lee, W.W.; Ethier, S.; Lewandowski, J.L.V.; Rewoldt, G.; Hahm, T.S.; Manickam, J.

    2006-01-01

    A general geometry gyro-kinetic model for particle simulation of plasma turbulence in tokamak experiments is described. It incorporates the comprehensive influence of noncircular cross section, realistic plasma profiles, plasma rotation, neoclassical (equilibrium) electric fields, and Coulomb collisions. An interesting result of global turbulence development in a shaped tokamak plasma is presented with regard to nonlinear turbulence spreading into the linearly stable region. The mutual interaction between turbulence and zonal flows in collisionless plasmas is studied with a focus on identifying possible nonlinear saturation mechanisms for zonal flows. A bursting temporal behavior with a period longer than the geodesic acoustic oscillation period is observed even in a collisionless system. Our simulation results suggest that the zonal flows can drive turbulence. However, this process is too weak to be an effective zonal flow saturation mechanism.

  9. Ground based simulation of life sciences Spacelab experiments

    NASA Technical Reports Server (NTRS)

    Rummel, J. A.; Alexander, W. C.; Bush, W. H.; Johnston, R. S.

    1978-01-01

    The third in a series of Spacelab Mission Development tests was a joint effort of the Ames Research and Johnson Space Centers to evaluate planned operational concepts of the Space Shuttle life sciences program. A three-man crew conducted 26 experiments and 12 operational tests, utilizing both human and animal subjects. The crew lived aboard an Orbiter/Spacelab mockup for the seven-day simulation. The Spacelab was identical in geometry to the European Space Agency design, complete with removable rack sections and stowage provisions. Communications were controlled as currently planned for operational Shuttle flights. A Science Operations Remote Center at the Ames Research Center was managed by simulated Mission Control and Payload Operation Control Centers at the Johnson Space Center. This paper presents the test objectives, describes the facilities and test program, and outlines the results of this test.

  10. The TESS (Tandem Experiment Simulation Studies) computer code user's manual

    SciTech Connect

    Procassini, R.J. . Dept. of Nuclear Engineering); Cohen, B.I. )

    1990-06-01

    TESS (Tandem Experiment Simulation Studies) is a one-dimensional, bounded particle-in-cell (PIC) simulation code designed to investigate the confinement and transport of plasma in a magnetic mirror device, including tandem mirror configurations. Mirror plasmas may be modeled in a system which includes an applied magnetic field and/or a self-consistent or applied electrostatic potential. The PIC code TESS is similar to the PIC code DIPSI (Direct Implicit Plasma Surface Interactions) which is designed to study plasma transport to and interaction with a solid surface. The codes TESS and DIPSI are direct descendants of the PIC code ES1 that was created by A. B. Langdon. This document provides the user with a brief description of the methods used in the code and a tutorial on the use of the code. 10 refs., 2 tabs.

  11. Comparison of simulation with experiment in an RFQ

    SciTech Connect

    Boicourt, G.P.; Sander, O.R.; Wangler, T.P.

    1985-01-01

    The accelerator test stand (ATS) RFQ has provided an opportunity to compare the predictions of the RFQ beam-dynamics code PARMTEQ with actual operation of an RFQ. For this comparison, the code was adapted to simulate the measured operation parameters, which are somewhat different from those of the ideal design. A Monte Carlo code was written to provide input to PARMTEQ, based on measured input beam distributions. With these refinements, the code has given results that are in good agreement with measurements and has provided information leading to an explanation of an unexpected set of measurements. This paper describes the method used to generate a pseudo particle beam based on the measured transverse properties of the RFQ input beam and describes some of the comparisons between simulation and experiment. An explanation is provided for the energy-spectrum structure observed in the RFQ output beam during low-voltage operation. 3 refs., 7 figs.

  12. Wakefield Simulations for the Laser Acceleration Experiment at SLAC

    SciTech Connect

    Ng, Johnny

    2012-04-18

    Laser-driven acceleration in dielectric photonic band gap structures can provide gradients on the order of GeV/m. The small transverse dimension of the structure, on the order of the laser wavelength, presents interesting wakefield-related issues. Higher order modes can seriously degrade beam quality, and a detailed understanding is needed to mitigate such effects. On the other hand, wakefields also provide a direct way to probe the interaction of a relativistic bunch with the synchronous modes supported by the structure. Simulation studies have been carried out as part of the effort to understand the impact on beam dynamics, and to compare with data from beam experiments designed to characterize candidate structures. In this paper, we present simulation results of wakefields excited by a sub-wavelength bunch in optical photonic band gap structures.

  13. Comparison of simulation with experiment in an RFQ

    SciTech Connect

    Boicourt, G.P.; Sander, O.R.; Wangler, T.P.

    1985-10-01

    The accelerator test stand (ATS) RFQ has provided an opportunity to compare the predictions of the RFQ beam-dynamics code PARMTEQ with actual operation of an RFQ. For this comparison, the code was adapted to simulate the measured operation parameters, which are somewhat different from those of the ideal design. A Monte Carlo code was written to provide input to PARMTEQ, based on measured input beam distributions. With these refinements, the code has given results that are in good agreement with measurements and has provided information leading to an explanation of an unexpected set of measurements. This paper describes the method used to generate a pseudo particle beam based on the measured transverse properties of the RFQ input beam and describes some of the comparisons between simulation and experiment. An explanation is provided for the energy-spectrum structure observed in the RFQ output beam during low-voltage operation.

  14. Non-robust numerical simulations of analogue extension experiments

    NASA Astrophysics Data System (ADS)

    Naliboff, John; Buiter, Susanne

    2016-04-01

    Numerical and analogue models of lithospheric deformation provide significant insight into the tectonic processes that lead to specific structural and geophysical observations. As these two types of models contain distinct assumptions and tradeoffs, investigations drawing conclusions from both can reveal robust links between first-order processes and observations. Recent studies have focused on detailed comparisons between numerical and analogue experiments in both compressional and extensional tectonics, sometimes involving multiple lithospheric deformation codes and analogue setups. While such comparisons often show good agreement on first-order deformation styles, results frequently diverge on second-order structures, such as shear zone dip angles or spacing, and in certain cases even on first-order structures. Here, we present finite-element experiments that are designed to directly reproduce analogue "sandbox" extension experiments at the cm-scale. We use material properties and boundary conditions that are directly taken from analogue experiments and use a Drucker-Prager failure model to simulate shear zone formation in sand. We find that our numerical experiments are highly sensitive to numerous numerical parameters. For example, changes to the numerical resolution, velocity convergence parameters and elemental viscosity averaging commonly produce significant changes in first- and second-order structures accommodating deformation. The sensitivity of the numerical simulations to small parameter changes likely reflects a number of factors, including, but not limited to, high angles of internal friction assigned to sand, complex, unknown interactions between the brittle sand (used as an upper crust equivalent) and viscous silicone (lower crust), highly non-linear strain weakening processes and poor constraints on the cohesion of sand. Our numerical-analogue comparison is hampered by (a) an incomplete knowledge of the fine details of sand failure and sand

  15. Event-based Simulation Model for Quantum Optics Experiments

    SciTech Connect

    De Raedt, H.; Michielsen, K.

    2011-03-28

    We present a corpuscular simulation model of optical phenomena that does not require the knowledge of the solution of a wave equation of the whole system and reproduces the results of Maxwell's theory by generating detection events one-by-one. The event-based corpuscular model gives a unified description of multiple-beam fringes of a plane parallel plate and single-photon Mach-Zehnder interferometer, Wheeler's delayed choice, photon tunneling, quantum eraser, two-beam interference, double-slit, Einstein-Podolsky-Rosen-Bohm and Hanbury Brown-Twiss experiments. We also discuss the possibility to refute our corpuscular model.

  16. Sequencing of Simulation and Clinic Experiences in an Introductory Pharmacy Practice Experience

    PubMed Central

    Hajjar, Emily; DeSevo Bellottie, Gina

    2015-01-01

    Objective. To examine how the intrasemester sequencing of a simulation component, delivered during an ambulatory care introductory pharmacy practice experience (IPPE), affects student performance on a series of 3 assessments delivered during the second professional (P2) year. Design. At the Jefferson College of Pharmacy (JCP), P2 student pharmacists were randomly assigned to 6 weeks of simulation activities, followed by 6 weeks on site at an ambulatory care clinic or vice versa during either the fall or spring semesters. At the end of each semester, these students completed 3 skills-based assessments: answering a series of drug information (DI) questions; conducting medication adherence counseling; and conducting a medication history. The 2 groups’ raw scores on assessment rubrics were compared. Assessment. During academic years 2011-2012 and 2012-2013, 180 P2 student pharmacists participated in the required ambulatory care IPPE. Ninety experienced simulation first, while the other 90 experienced the clinic first. Students assessed over a 2-year time span performed similarly on each of 3 skills-based assessments, regardless of how simulation experiences were sequenced within the IPPE. Conclusion. The lack of significant difference in student performance suggests that schools of pharmacy may have flexibility with regard to how they choose to incorporate simulation into clinical ambulatory care IPPEs. PMID:26688585

  17. Initial NIF Shock Timing Experiments: Comparison with Simulation

    NASA Astrophysics Data System (ADS)

    Robey, H. F.; Celliers, P. M.; Boehly, T. R.; Datte, P. S.; Bowers, M. W.; Olson, R. E.; Munro, D. H.; Milovich, J. L.; Jones, O. S.; Nikroo, A.; Kroll, J. J.; Horner, J. B.; Hamza, A. V.; Bhandarkar, S. D.; Giraldez, E.; Castro, C.; Gibson, C. R.; Eggert, J. H.; Smith, R. F.; Park, H.-S.; Young, B. K.; Hsing, W. W.; Landen, O. L.; Meyerhofer, D. D.

    2010-11-01

    Initial experiments are underway to demonstrate the techniques required to tune the shock timing of capsule implosions on the National Ignition Facility (NIF). These experiments use a modified cryogenic hohlraum geometry designed to precisely match the performance of ignition hohlraums. The targets employ a re-entrant Au cone to provide optical access to the shocks as they propagate in the liquid deuterium-filled capsule interior. The strength and timing of the shocks is diagnosed with VISAR (Velocity Interferometer System for Any Reflector) and DANTE. The results of these measurements will be used to set the precision pulse shape for ignition capsule implosions to follow. Experimental results and comparisons with numerical simulation are presented.

  18. Evaluation of a mesoscale atmospheric dispersion modeling system with observations from the 1980 Great Plains mesoscale tracer field experiment. Part II: Dispersion simulations

    SciTech Connect

    Moran, M.D.; Pielke, R.A.

    1996-03-01

    A mesoscale atmospheric dispersion (MAD) numerical modeling system, consisting of a mesoscale meteorological model coupled to a mesoscale Lagrangian particle dispersion model (MLPDM), was used to simulate the emission, transport, and diffusion of a perfluorocarbon tracer-gas cloud for a surface release during a tracer field experiment. The MLPDM was run for a baseline simulation and seven sensitivity experiments. The baseline simulation showed considerable skill in predicting peak ground-level concentration (GLC), maximum cloud width, cloud arrival and transit times, and crosswind integrated exposure at downwind distances of 100 and 600 km. The baseline simulation also compared very well to simulations made by seven other MAD models for the same case in an earlier study. The sensitivity experiments explored the impact of various factors on MAD, especially the diurnal heating cycle and physiographic and atmospheric inhomogeneities, by including or excluding them in different combinations. The GLC footprints predicted in sensitivity experiments were sensitive to differences in simulated meteorological fields. The observations and numerical simulations suggest that the nocturnal low-level jet played an important role in transporting and deforming the tracer cloud during this MAD experiment: the mean transport speed was supergeostrophic and both crosswind and alongwind cloud spreads were larger than can be explained by turbulent diffusion alone. The contributions of differential horizontal advection and mesoscale deformation to MAD dominate those of small-scale turbulent diffusion for this case, and Pasquill`s delayed-shear enhancement mechanism for horizontal diffusion appears to have played a significant role during nighttime transport. These results demonstrate the need in some flow regimes for better temporal resolution of boundary layer vertical shear in MAD models than is available from the conventional twice-daily rawinsonde network. 34 refs., 14 figs., 4 tabs.

  19. Evaluation of a Mesoscale Atmospheric Dispersion Modeling System with Observations from the 1980 Great Plains Mesoscale Tracer Field Experiment. Part II: Dispersion Simulations.

    NASA Astrophysics Data System (ADS)

    Moran, Michael D.; Piekle, Roger A.

    1996-03-01

    The Colorado State University mesoscale atmospheric dispersion (MAD) numerical modeling system, which consists of a prognostic mesoscale meteorological model coupled to a mesoscale Lagrangian particle dispersion model (MLPDM), has been used to simulate the emission, transport, and diffusion of a perfluorocarbon tracer-gas cloud for one afternoon surface release during the July 1980 Great Plains mesoscale tracer field experiment. The MLPDM was run for a baseline simulation and seven sensitivity experiments. The baseline simulation showed considerable skill in predicting such quantitative whole-could characteristics as peak ground-level concentration (GLC), maximum cloud width, cloud arrival and transit times, and crosswind integrated exposure at downwind distances of both 100 and 60 km. The baseline simulation also compared very favorably to simulations made by seven other MAD models for this same case in an earlier study. The sensitivity experiments explored the impact of various factors on MAD, especially the diurnal heating cycle and physiographic and atmospheric inhomogeneities, by including or excluding them in different combinations. The GLC `footprints' predicted in the sensitivity experiments were sensitive to differences in the simulated meteorological fields.The observations and the numerical simulations both suggest that the Great Plains nocturnal low-level jet played an important role in transporting and deforming the perfluorocarbon tracer cloud during this MAD experiment: the mean transport speed was supergeostrophic and both crosswind and alongwind cloud spreads were larger than can be explained by turbulent diffusion alone. The contributions of differential horizontal advection and mesoscale deformation to MAD dominate those of small-scale turbulent diffusion for this case, and Pasquill's delayed-shear enhancement mechanism for horizontal diffusion appears to have played a significant role during nighttime transport. These results demonstrate the

  20. Cryogenic Fracturing: Laboratory Visualization Experiments and Numerical Simulations Using Peridynamics

    NASA Astrophysics Data System (ADS)

    Martin-Short, R.; Edmiston, J. K.

    2015-12-01

    Typical hydraulic fracturing operations involve the use of a large quantity of water, which can be problematic for several reasons including possible formation (permeability) damage, disposal of waste water, and the use of precious local water resource. An alternate reservoir permeability enhancing technology not requiring water is cryogenic fracturing. This method induces controlled fracturing of rock formations by thermal shock and has potentially important applications in the geothermal and hydrocarbon industries. In this process, cryogenic fluid—such as liquid nitrogen—is injected into the subsurface, causing fracturing due to thermal gradients. These fractures may improve the formation permeability relative to that achievable by hydraulic fracturing alone. We conducted combined laboratory visualization and numerical simulations studies of thermal-shock-induced fracture initiation and propagation resulting from liquid nitrogen injection in rock and analog materials. The experiment used transparent soda-lime glass cubes to facilitate real-time visualization of fracture growth and the fracture network geometry. In this contribution, we report the effect of overall temperature difference between cryogenic fluid and solid material on the produced fracture network, by pre-heating the glass cubes to several temperatures and injecting liquid nitrogen. Temperatures are monitored at several points by thermocouple and the fracture evolution is captured visually by camera. The experiment was modeled using a customized, thermoelastic, fracture-capable numerical simulation code based on peridynamics. The performance of the numerical code was validated by the results of the laboratory experiments, and then the code was used to study the different factors affecting a cryogenic fracturing operation, including the evolution of residual stresses and constitutive relationships for material failure. In complex rock such as shale, understanding the process of cryogenic

  1. Hybrid Reynolds-Averaged/Large-Eddy Simulations of a Co-Axial Supersonic Free-Jet Experiment

    NASA Technical Reports Server (NTRS)

    Baurle, R. A.; Edwards, J. R.

    2009-01-01

    Reynolds-averaged and hybrid Reynolds-averaged/large-eddy simulations have been applied to a supersonic coaxial jet flow experiment. The experiment utilized either helium or argon as the inner jet nozzle fluid, and the outer jet nozzle fluid consisted of laboratory air. The inner and outer nozzles were designed and operated to produce nearly pressure-matched Mach 1.8 flow conditions at the jet exit. The purpose of the computational effort was to assess the state-of-the-art for each modeling approach, and to use the hybrid Reynolds-averaged/large-eddy simulations to gather insight into the deficiencies of the Reynolds-averaged closure models. The Reynolds-averaged simulations displayed a strong sensitivity to choice of turbulent Schmidt number. The baseline value chosen for this parameter resulted in an over-prediction of the mixing layer spreading rate for the helium case, but the opposite trend was noted when argon was used as the injectant. A larger turbulent Schmidt number greatly improved the comparison of the results with measurements for the helium simulations, but variations in the Schmidt number did not improve the argon comparisons. The hybrid simulation results showed the same trends as the baseline Reynolds-averaged predictions. The primary reason conjectured for the discrepancy between the hybrid simulation results and the measurements centered around issues related to the transition from a Reynolds-averaged state to one with resolved turbulent content. Improvements to the inflow conditions are suggested as a remedy to this dilemma. Comparisons between resolved second-order turbulence statistics and their modeled Reynolds-averaged counterparts were also performed.

  2. Microwave window breakdown experiments and simulations on the UM/L-3 relativistic magnetron.

    PubMed

    Hoff, B W; Mardahl, P J; Gilgenbach, R M; Haworth, M D; French, D M; Lau, Y Y; Franzi, M

    2009-09-01

    Experiments have been performed on the UM/L-3 (6-vane, L-band) relativistic magnetron to test a new microwave window configuration designed to limit vacuum side breakdown. In the baseline case, acrylic microwave windows were mounted between three of the waveguide coupling cavities in the anode block vacuum housing and the output waveguides. Each of the six 3 cm deep coupling cavities is separated from its corresponding anode cavity by a 1.75 cm wide aperture. In the baseline case, vacuum side window breakdown was observed to initiate at single waveguide output powers close to 20 MW. In the new window configuration, three Air Force Research Laboratory-designed, vacuum-rated directional coupler waveguide segments were mounted between the coupling cavities and the microwave windows. The inclusion of the vacuum side power couplers moved the microwave windows an additional 30 cm away from the anode apertures. Additionally, the Lucite microwave windows were replaced with polycarbonate windows and the microwave window mounts were redesigned to better maintain waveguide continuity in the region around the microwave windows. No vacuum side window breakdown was observed in the new window configuration at single waveguide output powers of 120+MW (a factor of 3 increase in measured microwave pulse duration and factor of 3 increase in measured peak power over the baseline case). Simulations were performed to investigate likely causes for the window breakdown in the original configuration. Results from these simulations have shown that in the original configuration, at typical operating voltage and magnetic field ranges, electrons emitted from the anode block microwave apertures strike the windows with a mean kinetic energy of 33 keV with a standard deviation of 14 keV. Calculations performed using electron impact angle and energy data predict a first generation secondary electron yield of 65% of the primary electron population. The effects of the primary aperture electron

  3. Baseline Predictors of A1C Reduction in Adults Using Sensor-Augmented Pump Therapy or Multiple Daily Injection Therapy: The STAR 3 Experience

    PubMed Central

    Dailey, George; Ahmann, Andrew A.; Bergenstal, Richard M.; Green, Jennifer B.; Peoples, Tim; Tanenberg, Robert J.; Yang, Qingqing

    2011-01-01

    Abstract Background Baseline characteristics from the adult cohort of a randomized controlled trial comparing sensor-augmented pump (SAP) and multiple daily injection (MDI) therapy were analyzed for significant relationships with −0.5% A1C change at 1 year of therapy without incidence of severe hypoglycemia (defined as A1C benefit). Methods Baseline characteristics were compared with A1C benefit. Statistically significant predictors were analyzed further to determine appropriate cutpoints of relative A1C benefit. Results Baseline A1C ≥9.1%, age at randomization ≥36 years, and age at diabetes diagnosis of ≥17 years were associated with a greater SAP benefit relative to MDI than other cutpoints. Conclusions People with type 1 diabetes who had a high A1C and who were older at diagnosis and older at randomization experienced the most benefit from SAP therapy. PMID:21488717

  4. Simulation of microtearing turbulence in national spherical torus experiment

    SciTech Connect

    Guttenfelder, W.; Kaye, S. M.; Bell, R. E.; Hammett, G. W.; LeBlanc, B. P.; Mikkelsen, D. R.; Ren, Y.; Candy, J.; Nevins, W. M.; Wang, E.; Zhang, J.; Crocker, N. A.; Yuh, H.

    2012-05-15

    Thermal energy confinement times in National Spherical Torus Experiment (NSTX) dimensionless parameter scans increase with decreasing collisionality. While ion thermal transport is neoclassical, the source of anomalous electron thermal transport in these discharges remains unclear, leading to considerable uncertainty when extrapolating to future spherical tokamak (ST) devices at much lower collisionality. Linear gyrokinetic simulations find microtearing modes to be unstable in high collisionality discharges. First non-linear gyrokinetic simulations of microtearing turbulence in NSTX show they can yield experimental levels of transport. Magnetic flutter is responsible for almost all the transport ({approx}98%), perturbed field line trajectories are globally stochastic, and a test particle stochastic transport model agrees to within 25% of the simulated transport. Most significantly, microtearing transport is predicted to increase with electron collisionality, consistent with the observed NSTX confinement scaling. While this suggests microtearing modes may be the source of electron thermal transport, the predictions are also very sensitive to electron temperature gradient, indicating the scaling of the instability threshold is important. In addition, microtearing turbulence is susceptible to suppression via sheared E Multiplication-Sign B flows as experimental values of E Multiplication-Sign B shear (comparable to the linear growth rates) dramatically reduce the transport below experimental values. Refinements in numerical resolution and physics model assumptions are expected to minimize the apparent discrepancy. In cases where the predicted transport is strong, calculations suggest that a proposed polarimetry diagnostic may be sensitive to the magnetic perturbations associated with the unique structure of microtearing turbulence.

  5. Shocked materials at the intersection of experiment and simulation

    SciTech Connect

    Kadau, Kai

    2008-01-01

    Understanding the dynamic lattice response of solids under the extreme conditions of pressure, temperature and strain rate is a scientific quest that spans nearly a century. Critical to developing this understanding is the ability to probe and model the spatial and temporal evolution of the material microstructure and properties at the scale of the relevant physical phenomena -- nanometers to micrometers and picoseconds to nanoseconds. While experimental investigations over this range of spatial and temporal scales were unimaginable just a decade ago, new technologies and facilities currently under development and on the horizon have brought these goals within reach for the first time. The equivalent advancements in simulation capabilities now mean that we can conduct simulations and experiments at overlapping temporal and spatial scales. In this article, we describe some of our studies which exploit existing and new generation ultrabright, ultrafast x-ray sources and large scale molecular dynamics simulations to investigate the real-time physical phenomena that control the dynamic response of shocked materials.

  6. A Little Vacation on Mars: Mars Simulation Microbial Challenge Experiments

    NASA Astrophysics Data System (ADS)

    Boston, P.; Todd, P.; Van De Camp, J.; Northup, D.; Spilde, M.

    2008-06-01

    Communities of microbial organisms isolated from a variety of extreme environments were subjected to 1 to 5 weeks of simulated Martian environmental conditions using the Mars Environment Simulation Chamber at the Techshot, Inc. facility in Greenville, Indiana. The goal of the overall experiment program was to assess survival of test Earth organisms under Mars full spectrum sunlight, low-latitude daily temperature profile and various Mars-atmosphere pressures (~50 mbar to 500 mbar, 100% CO2) and low moisture content. Organisms surviving after 5 weeks at 100 mbar included those from gypsum surface fracture communities in a Permian aged evaporite basin, desert varnish on andesite lavas around a manganese mine, and iron and manganese oxidizing organisms isolated from two caves in Mew Mexico. Phylogenetic DNA analysis revealed strains of cyanobacteria, bacterial genera (present in all surviving communities) Asticacaulis, Achromobacter, Comamonas, Pantoea, Verrucomicrobium, Bacillus, Gemmatimonas, Actinomyces, and others. At least one microcolonial fungal strain from a desert varnish community and at least one strain from Utah survived simulations. Strains related to the unusual cave bacterial group Bacteroidetes are present in survivor communities that resist isolation into pure culture implying that their consortial relationships may be critical to their survival.

  7. A simulation of the San Andreas fault experiment

    NASA Technical Reports Server (NTRS)

    Agreen, R. W.; Smith, D. E.

    1974-01-01

    The San Andreas fault experiment (Safe), which employs two laser tracking systems for measuring the relative motion of two points on opposite sides of the fault, has been simulated for an 8-yr observation period. The two tracking stations are located near San Diego on the western side of the fault and near Quincy on the eastern side; they are roughly 900 km apart. Both will simultaneously track laser reflector equipped satellites as they pass near the stations. Tracking of the Beacon Explorer C spacecraft has been simulated for these two stations during August and September for 8 consecutive years. An error analysis of the recovery of the relative location of Quincy from the data has been made, allowing for model errors in the mass of the earth, the gravity field, solar radiation pressure, atmospheric drag, errors in the position of the San Diego site, and biases and noise in the laser systems. The results of this simulation indicate that the distance of Quincy from San Diego will be determined each year with a precision of about 10 cm. Projected improvements in these model parameters and in the laser systems over the next few years will bring the precision to about 1-2 cm by 1980.

  8. A simulation of the San Andreas fault experiment

    NASA Technical Reports Server (NTRS)

    Agreen, R. W.; Smith, D. E.

    1973-01-01

    The San Andreas Fault Experiment, which employs two laser tracking systems for measuring the relative motion of two points on opposite sides of the fault, was simulated for an eight year observation period. The two tracking stations are located near San Diego on the western side of the fault and near Quincy on the eastern side; they are roughly 900 kilometers apart. Both will simultaneously track laser reflector equipped satellites as they pass near the stations. Tracking of the Beacon Explorer C Spacecraft was simulated for these two stations during August and September for eight consecutive years. An error analysis of the recovery of the relative location of Quincy from the data was made, allowing for model errors in the mass of the earth, the gravity field, solar radiation pressure, atmospheric drag, errors in the position of the San Diego site, and laser systems range biases and noise. The results of this simulation indicate that the distance of Quincy from San Diego will be determined each year with a precision of about 10 centimeters. This figure is based on the accuracy of earth models and other parameters available in 1972.

  9. Shocked materials at the intersection of experiment and simulation

    SciTech Connect

    Lorenzana, H. E.; Belak, J. F.; Bradley, K. S.; Bringa, E. M.; Budil, K. S.; Cazamias, J. U.; El-Dasher, B.; Hawreliak, J. A.; Hessler, J.; Kadau, K.; Kalantar, D. H.; McNaney, J. M.; Milathianaki, D.; Rosolankova, K.; Swift, D. C.; Taravillo, M.; Van Buuren, T. W.; Wark, J. S.; de la Rubia, T. Diaz

    2008-04-01

    Understanding the dynamic lattice response of solids under the extreme conditions of pressure, temperature and strain rate is a scientific quest that spans nearly a century. Critical to developing this understanding is the ability to probe and model the spatial and temporal evolution of the material microstructure and properties at the scale of the relevant physical phenomena-nanometers to micrometers and picoseconds to nanoseconds. While experimental investigations over this range of spatial and temporal scales were unimaginable just a decade ago, new technologies and facilities currently under development and on the horizon have brought these goals within reach for the first time. The equivalent advancements in simulation capabilities now mean that we can conduct simulations and experiments at overlapping temporal and spatial scales. In this article, we describe some of our studies which exploit existing and new generation ultrabright, ultrafast x-ray sources and large scale molecular dynamics simulations to investigate the real-time physical phenomena that control the dynamic response of shocked materials.

  10. Rainfall simulation experiments with a small portable rainfall simulator: research on runoff generation and soil erosion

    NASA Astrophysics Data System (ADS)

    Iserloh, Thomas; Peter, Klaus Daniel; Fister, Wolfgang; Wirtz, Stefan; Butzen, Verena; Brings, Christine; Marzen, Miriam; Casper, Markus C.; Seeger, Manuel; Ries, Johannes B.

    2015-04-01

    The results of more than 500 rainfall simulations with a small portable rainfall simulator at various locations in West and North Africa and South and Central Europe will be presented. The analysis of this comprehensive database offers results concerning different research objectives: - erodibility of local soils regarding different vegetation cover, stone cover and land uses - runoff generation in gully catchments - process oriented experiments on the influence of sealing and crusting - trail erosion caused by goat- or sheep-trampling - recent erosion on geomorphological forms Runoff coefficients range from 0 to 100 % and eroded material from 0 to 500 g m^-2 during 30 min experiments with a rainfall intensity of 40 mm h^-1.

  11. Simulation of nucleation in almost hard-sphere colloids: The discrepancy between experiment and simulation persists

    NASA Astrophysics Data System (ADS)

    Filion, L.; Ni, R.; Frenkel, D.; Dijkstra, M.

    2011-04-01

    In this paper we examine the phase behavior of the Weeks-Chandler-Andersen (WCA) potential with βɛ = 40. Crystal nucleation in this model system was recently studied by Kawasaki and Tanaka [Proc. Natl. Acad. Sci. U.S.A. 107, 14036 (2010)], 10.1021/pr100656u, who argued that the computed nucleation rates agree well with experiment, a finding that contradicted earlier simulation results. Here we report an extensive numerical study of crystallization in the WCA model, using three totally different techniques (Brownian dynamics, umbrella sampling, and forward flux sampling). We find that all simulations yield essentially the same nucleation rates. However, these rates differ significantly from the values reported by Kawasaki and Tanaka and hence we argue that the huge discrepancy in nucleation rates between simulation and experiment persists. When we map the WCA model onto a hard-sphere system, we find good agreement between the present simulation results and those that had been obtained for hard spheres [L. Filion, M. Hermes, R. Ni, and M. Dijkstra, J. Chem. Phys. 133, 244115 (2010), 10.1063/1.3506838; S. Auer and D. Frenkel, Nature 409, 1020 (2001), 10.1038/35059035].

  12. The World Climate Exercise: Is (Simulated) Experience Our Best Teacher?

    NASA Astrophysics Data System (ADS)

    Rath, K.; Rooney-varga, J. N.; Jones, A.; Johnston, E.; Sterman, J.

    2015-12-01

    Meeting the challenge of climate change will clearly require 'deep learning' - learning that motivates a search for underlying meaning, a willingness to exert the sustained effort needed to understand complex problems, and innovative problem-solving. This type of learning is dependent on the level of the learner's engagement with the material, their intrinsic motivation to learn, intention to understand, and relevance of the material to the learner. Here, we present evidence for deep learning about climate change through a simulation-based role-playing exercise, World Climate. The exercise puts participants into the roles of delegates to the United Nations climate negotiations and asks them to create an international climate deal. They find out the implications of their decisions, according to the best available science, through the same decision-support computer simulation used to provide feedback for the real-world negotiations, C-ROADS. World Climate provides an opportunity for participants have an immersive, social experience in which they learn first-hand about both the social dynamics of climate change decision-making, through role-play, and the dynamics of the climate system, through an interactive computer simulation. Evaluation results so far have shown that the exercise is highly engaging and memorable and that it motivates large majorities of participants (>70%) to take action on climate change. In addition, we have found that it leads to substantial gains in understanding key systems thinking concepts (e.g., the stock-flow behavior of atmospheric CO2), as well as improvements in understanding of climate change causes and impacts. While research is still needed to better understand the impacts of simulation-based role-playing exercises like World Climate on behavior change, long-term understanding, transfer of systems thinking skills across topics, and the importance of social learning during the exercise, our results to date indicate that it is a

  13. Numerical simulation of the hydrodynamic instability experiments and flow mixing

    NASA Astrophysics Data System (ADS)

    Bai, Jingsong; Wang, Tao; Li, Ping; Zou, Liyong; Liu, Cangli

    2009-12-01

    Based on the numerical methods of volume of fluid (VOF) and piecewise parabolic method (PPM) and parallel circumstance of Message Passing Interface (MPI), a parallel multi-viscosity-fluid hydrodynamic code MVPPM (Multi-Viscosity-Fluid Piecewise Parabolic Method) is developed and performed to study the hydrodynamic instability and flow mixing. Firstly, the MVPPM code is verified and validated by simulating three instability cases: The first one is a Riemann problem of viscous flow on the shock tube; the second one is the hydrodynamic instability and mixing of gaseous flows under re-shocks; the third one is a half height experiment of interfacial instability, which is conducted on the AWE’s shock tube. By comparing the numerical results with experimental data, good agreement is achieved. Then the MVPPM code is applied to simulate the two cases of the interfacial instabilities of jelly models accelerated by explosion products of a gaseous explosive mixture (GEM), which are adopted in our experiments. The first is implosive dynamic interfacial instability of cylindrical symmetry and mixing. The evolving process of inner and outer interfaces, and the late distribution of mixing mass caused by Rayleigh-Taylor (RT) instability in the center of different radius are given. The second is jelly layer experiment which is initialized with one periodic perturbation with different amplitude and wave length. It reveals the complex processes of evolution of interface, and presents the displacement of front face of jelly layer, bubble head and top of spike relative to initial equilibrium position vs. time. The numerical results are in excellent agreement with that experimental images, and show that the amplitude of initial perturbations affects the evolvement of fluid mixing zone (FMZ) growth rate extremely, especially at late times.

  14. Comparison of Electron Cloud Simulation and Experiments in the High-Current Experiment

    SciTech Connect

    Cohen, R H; Friedman, A; Covo, M K; Lund, S M; Molvik, A W; Bieniosek, F M; Seidl, P A; Vay, J; Stoltz, P; Veitzer, S

    2004-11-11

    Contaminating clouds of electrons are a common concern for accelerators of positive-charged particles, but there are some unique aspects of heavy-ion accelerators for fusion and high-energy density physics which make modeling such clouds especially challenging. In particular, self-consistent electron and ion simulation is required, including a particle advance scheme which can follow electrons in regions where electrons are strongly, weakly, and un-magnetized. We describe our approach to such self-consistency, and in particular a scheme for interpolating between full-orbit (Boris) and drift-kinetic particle pushes that enables electron time steps long compared to the typical gyro period in the magnets. We present tests and applications: simulation of electron clouds produced by three different kinds of sources indicates the sensitivity of the cloud shape to the nature of the source; first-of-a-kind self-consistent simulation of electron-cloud experiments on the High-Current Experiment (HCX) at LBNL, in which the machine can be flooded with electrons released by impact of the ion beam on an end plate, demonstrate the ability to reproduce key features of the ion-beam phase space; and simulation of a two-stream instability of thin beams in a magnetic field demonstrate the ability of the large-timestep mover to accurately calculate the instability.

  15. Laboratory simulations of the pyrolytic release experiments - An interim report

    NASA Technical Reports Server (NTRS)

    Hubbard, J. S.

    1979-01-01

    During its operation on Mars the pyrolytic release experiment (PR) detected the fixation of small amounts of CO2 and/or CO. Laboratory simulations of the experimental conditions were made in an attempt to substantiate the previous conclusion that these reactions were chemical rather than biological. After pretreatment and incubation under various conditions, pyrolytic analysis was used to indicate the extent of surface catalyzed conversion of (C-14)O2 or (C-14)O to (C-14)-organic compounds. This abiotic synthesis was detected in experiments with three iron oxides, viz. hematite, magnetite and maghemite. When the incubation atmosphere was supplemented with water vapor, the levels of synthesis were in a range comparable to that detected in the Viking PR tests. An abiotic synthesis was also detected in experiments with a mixture of clays and minerals (Mars analog soil) or with montmorillonite artificially enriched in iron. With either substratum the reaction appeared to be the result of a photocatalytic synthesis of (C-14)-organics from (C-14)O and surface hydroxyl groups. This process was not dependent on the presence of water vapor in the incubation atmosphere. Although a duplication of the Viking data has not been achieved, these findings support the abiotic interpretation of the PR results.

  16. Monte Carlo simulation experiments on box-type radon dosimeter

    NASA Astrophysics Data System (ADS)

    Jamil, Khalid; Kamran, Muhammad; Illahi, Ahsan; Manzoor, Shahid

    2014-11-01

    Epidemiological studies show that inhalation of radon gas (222Rn) may be carcinogenic especially to mine workers, people living in closed indoor energy conserved environments and underground dwellers. It is, therefore, of paramount importance to measure the 222Rn concentrations (Bq/m3) in indoors environments. For this purpose, box-type passive radon dosimeters employing ion track detector like CR-39 are widely used. Fraction of the number of radon alphas emitted in the volume of the box type dosimeter resulting in latent track formation on CR-39 is the latent track registration efficiency. Latent track registration efficiency is ultimately required to evaluate the radon concentration which consequently determines the effective dose and the radiological hazards. In this research, Monte Carlo simulation experiments were carried out to study the alpha latent track registration efficiency for box type radon dosimeter as a function of dosimeter's dimensions and range of alpha particles in air. Two different self developed Monte Carlo simulation techniques were employed namely: (a) Surface ratio (SURA) method and (b) Ray hitting (RAHI) method. Monte Carlo simulation experiments revealed that there are two types of efficiencies i.e. intrinsic efficiency (ηint) and alpha hit efficiency (ηhit). The ηint depends upon only on the dimensions of the dosimeter and ηhit depends both upon dimensions of the dosimeter and range of the alpha particles. The total latent track registration efficiency is the product of both intrinsic and hit efficiencies. It has been concluded that if diagonal length of box type dosimeter is kept smaller than the range of alpha particle then hit efficiency is achieved as 100%. Nevertheless the intrinsic efficiency keeps playing its role. The Monte Carlo simulation experimental results have been found helpful to understand the intricate track registration mechanisms in the box type dosimeter. This paper explains that how radon concentration from the

  17. Nonadiabatic molecular dynamics simulations: synergies between theory and experiments.

    PubMed

    Tavernelli, Ivano

    2015-03-17

    Recent developments in nonadiabatic dynamics enabled ab inito simulations of complex ultrafast processes in the condensed phase. These advances have opened new avenues in the study of many photophysical and photochemical reactions triggered by the absorption of electromagnetic radiation. In particular, theoretical investigations can be combined with the most sophisticated femtosecond experimental techniques to guide the interpretation of measured time-resolved observables. At the same time, the availability of experimental data at high (spatial and time) resolution offers a unique opportunity for the benchmarking and the improvement of those theoretical models used to describe complex molecular systems in their natural environment. The established synergy between theory and experiments can produce a better understanding of new ultrafast physical and chemical processes at atomistic scale resolution. Furthermore, reliable ab inito molecular dynamics simulations can already be successfully employed as predictive tools to guide new experiments as well as the design of novel and better performing materials. In this paper, I will give a concise account on the state of the art of molecular dynamics simulations of complex molecular systems in their excited states. The principal aim of this approach is the description of a given system of interest under the most realistic ambient conditions including all environmental effects that influence experiments, for instance, the interaction with the solvent and with external time-dependent electric fields, temperature, and pressure. To this end, time-dependent density functional theory (TDDFT) is among the most efficient and accurate methods for the representation of the electronic dynamics, while trajectory surface hopping gives a valuable representation of the nuclear quantum dynamics in the excited states (including nonadiabatic effects). Concerning the environment and its effects on the dynamics, the quantum mechanics

  18. Observing System Simulation Experiment for Global Precipitation Mission

    NASA Astrophysics Data System (ADS)

    Mishra, A. K.; Krishnamurti, T. N.

    2012-03-01

    From the suite of future Global Precipitation Mission (GPM) satellites we have selected 11 of the possible contributors to the NASA's International precipitation measurement program. The Observing System Simulation Experiments (OSSE) presented here explores the predictive usefulness of this suite of satellites. In order to carry out such experiments a Nature Run based on results from a state of the model is required. For that purpose we have selected recent past runs from the European Center for Medium Range Forecasts (ECMWF). These were designated as special data sets for OSSEs in partnership between NASA, NCEP/EMC, and NOAA. In order to test the usefulness of these future GPM-based precipitation measurements we first identify the typical orbits of eleven satellites. Along these orbital tracks we generate proxy precipitation data sets from the ECMWF Nature Run. This method of extraction of precipitation data set from a Nature Run is described in this paper. This methodology also requires a fraternal twin model (different from the Nature Run) in which the usefulness of the proposed GPM proxy data sets from the Nature Run are systematically evaluated in a forecast mode. The procedure for incorporation of the rainfall data sets is called the rain rate initialization. Data from one or more satellites are sequentially introduced into the fraternal twin model (which is the Florida State University Global Spectral Model) during the initialization phase for a number of experiments. After the initialization of such precipitation data sets, forecast experiments are carried out with the fraternal twin. The question asked is, as we introduce more and more GPM satellites how close do the forecasts from the fraternal twin approach the Nature Run? The results from this experimentation show that very promising improvements for short-range precipitation forecast skills are attainable from the proposed suite of GPM satellites.

  19. Experiment and simulation on one-dimensional plasma photonic crystals

    SciTech Connect

    Zhang, Lin; Ouyang, Ji-Ting

    2014-10-15

    The transmission characteristics of microwaves passing through one-dimensional plasma photonic crystals (PPCs) have been investigated by experiment and simulation. The PPCs were formed by a series of discharge tubes filled with argon at 5 Torr that the plasma density in tubes can be varied by adjusting the discharge current. The transmittance of X-band microwaves through the crystal structure was measured under different discharge currents and geometrical parameters. The finite-different time-domain method was employed to analyze the detailed properties of the microwaves propagation. The results show that there exist bandgaps when the plasma is turned on. The properties of bandgaps depend on the plasma density and the geometrical parameters of the PPCs structure. The PPCs can perform as dynamical band-stop filter to control the transmission of microwaves within a wide frequency range.

  20. Numerical Simulations of the Boundary Layer Transition Flight Experiment

    NASA Technical Reports Server (NTRS)

    Tang, Chun Y.; Trumble, Kerry A.; Campbell, Charles H.; Lessard, Victor R.; Wood, William A.

    2010-01-01

    Computational Fluid Dynamics (CFD) simulations were used to study the possible effects that the Boundary Layer Transition (BLT) Flight Experiments may have on the heating environment of the Space Shuttle during its entry to Earth. To investigate this issue, hypersonic calculations using the Data-Parallel Line Relaxation (DPLR) and Langley Aerothermodynamic Upwind Relaxation (LAURA) CFD codes were computed for a 0.75 tall protuberance at flight conditions of Mach 15 and 18. These initial results showed high surface heating on the BLT trip and the areas surrounding the protuberance. Since the predicted peak heating rates would exceed the thermal limits of the materials selected to construct the BLT trip, many changes to the geometry were attempted in order to reduce the surface heat flux. The following paper describes the various geometry revisions and the resulting heating environments predicted by the CFD codes.

  1. Experiences using DAKOTA stochastic expansion methods in computational simulations.

    SciTech Connect

    Templeton, Jeremy Alan; Ruthruff, Joseph R.

    2012-01-01

    Uncertainty quantification (UQ) methods bring rigorous statistical connections to the analysis of computational and experiment data, and provide a basis for probabilistically assessing margins associated with safety and reliability. The DAKOTA toolkit developed at Sandia National Laboratories implements a number of UQ methods, which are being increasingly adopted by modeling and simulation teams to facilitate these analyses. This report disseminates results as to the performance of DAKOTA's stochastic expansion methods for UQ on a representative application. Our results provide a number of insights that may be of interest to future users of these methods, including the behavior of the methods in estimating responses at varying probability levels, and the expansion levels for the methodologies that may be needed to achieve convergence.

  2. First experience of vectorizing electromagnetic physics models for detector simulation

    SciTech Connect

    Amadio, G.; Apostolakis, J.; Bandieramonte, M.; Bianchini, C.; Bitzes, G.; Brun, R.; Canal, P.; Carminati, F.; Licht, J.de Fine; Duhem, L.; Elvira, D.; Gheata, A.; Jun, S. Y.; Lima, G.; Novak, M.; Presbyterian, M.; Shadura, O.; Seghal, R.; Wenzel, S.

    2015-12-23

    The recent emergence of hardware architectures characterized by many-core or accelerated processors has opened new opportunities for concurrent programming models taking advantage of both SIMD and SIMT architectures. The GeantV vector prototype for detector simulations has been designed to exploit both the vector capability of mainstream CPUs and multi-threading capabilities of coprocessors including NVidia GPUs and Intel Xeon Phi. The characteristics of these architectures are very different in terms of the vectorization depth, parallelization needed to achieve optimal performance or memory access latency and speed. An additional challenge is to avoid the code duplication often inherent to supporting heterogeneous platforms. In this paper we present the first experience of vectorizing electromagnetic physics models developed for the GeantV project.

  3. INEX (integrated numerical experiment) simulations of the Boeing FEL system

    SciTech Connect

    Tokar, R.L.; Young, L.M.; Lumpkin, A.H.; McVey, B.D.; Thode, L.E.; Bender, S.C.; Chan, K.C.D. ); Yeremian, A.D.; Dowell, D.H.; Lowrey, A.R. )

    1989-01-01

    The INEX (integrated numerical experiment) numerical model is applied to the 0.6 {mu}m FEL oscillator at Boeing Aerospace and Electronics Company in Seattle, WA. This system consists of a 110 MeV L-band rf linac, a beam transport line from the accelerator to the entrance of the wiggler, the 5.0 meter THUNDER variable taper wiggler, and a near concentric two mirror optical oscillator. Many aspects of the model for the electron beam accelerator and transport line agree with experimental measurements. Predictions for lasing performance are compared with data obtained in May and June 1989 using a mild tapered wiggler. We obtain good agreement with the achieved extraction efficiency, while 1D pulse simulations reproduce the observed sideband instability. 15 refs., 11 figs.

  4. First experience of vectorizing electromagnetic physics models for detector simulation

    NASA Astrophysics Data System (ADS)

    Amadio, G.; Apostolakis, J.; Bandieramonte, M.; Bianchini, C.; Bitzes, G.; Brun, R.; Canal, P.; Carminati, F.; de Fine Licht, J.; Duhem, L.; Elvira, D.; Gheata, A.; Jun, S. Y.; Lima, G.; Novak, M.; Presbyterian, M.; Shadura, O.; Seghal, R.; Wenzel, S.

    2015-12-01

    The recent emergence of hardware architectures characterized by many-core or accelerated processors has opened new opportunities for concurrent programming models taking advantage of both SIMD and SIMT architectures. The GeantV vector prototype for detector simulations has been designed to exploit both the vector capability of mainstream CPUs and multi-threading capabilities of coprocessors including NVidia GPUs and Intel Xeon Phi. The characteristics of these architectures are very different in terms of the vectorization depth, parallelization needed to achieve optimal performance or memory access latency and speed. An additional challenge is to avoid the code duplication often inherent to supporting heterogeneous platforms. In this paper we present the first experience of vectorizing electromagnetic physics models developed for the GeantV project.

  5. Simulation of the photogrammetric appendage structural dynamics experiment

    NASA Technical Reports Server (NTRS)

    Pappa, Richard S.; Gilbert, Michael G.; Welch, Sharon S.

    1995-01-01

    The Photogrammetric Appendage Structural Dynamics Experiment (PASDE) uses six video cameras in the Space Shuttle cargo bay to measure vibration of the Russian Mir space station Kvant-ll solar array. It occurs on Shuttle/Mir docking mission STS-74 scheduled for launch in November 1995. The objective of PASDE is to demonstrate photogrammetric technology for measuring 'untargeted' spacecraft appendage structural dynamics. This paper discusses a pre-flight simulation test conducted in July 1995, focusing on the image processing aspects. The flight camera system recorded vibrations of a full-scale structural test article having grids of white lines on black background, similar in appearance to the Mir solar array. Using image correlation analysis, line intersections on the structure are tracked in the video recordings to resolutions of less than 0.1 pixel. Calibration and merging of multiple camera views generated 3-dimensional displacements from which structural modal parameters are then obtained.

  6. An Atmospheric Science Observing System Simulation Experiment (OSSE) Environment

    NASA Technical Reports Server (NTRS)

    Lee, Meemong; Weidner, Richard; Qu, Zheng; Bowman, Kevin; Eldering, Annmarie

    2010-01-01

    An atmospheric sounding mission starts with a wide range of concept designs involving measurement technologies, observing platforms, and observation scenarios. Observing system simulation experiment (OSSE) is a technical approach to evaluate the relative merits of mission and instrument concepts. At Jet Propulsion Laboratory (JPL), the OSSE team has developed an OSSE environment that allows atmospheric scientists to systematically explore a wide range of mission and instrument concepts and formulate a science traceability matrix with a quantitative science impact analysis. The OSSE environment virtually creates a multi-platform atmospheric sounding testbed (MAST) by integrating atmospheric phenomena models, forward modeling methods, and inverse modeling methods. The MAST performs OSSEs in four loosely coupled processes, observation scenario exploration, measurement quality exploration, measurement quality evaluation, and science impact analysis.

  7. Assessment relative soil erodibility index by rainfall simulation experiment

    NASA Astrophysics Data System (ADS)

    Diaz, Jorge; Alonso, Gustavo; Leal, Zuzell; Ruiz, María. Elena; Almoza, Yeleine; Cornelis, Wim; Gabriels, Donald

    2010-05-01

    Soil erosion in agricultural fields is identified as the main source of sediments to the Cuyaguateje River, located in the western part of Cuba. The soil is highly variable across the whole watershed and an accurate estimate of soil erodibility is difficult to asses. A rainfall simulation experiment was carrying out in 16 different soils. Plots of 5 m long by 2 m wide with similar treatments and slope ranging from 5 to 15 % were selected. A constant rainfall intensity of 120 mm/h and 60 J/m2 h of kinetic energy, for 25 minutes was applied. Runoff and sediment concentration were measured every 2 minutes. Different behavior through the rainfall event was observed denoting differences in the mechanism driving the erosion process. The total soil lost during this event is reported as a relative index of soil erodibility. There is practically no correlation between this relative index and others soil erodibility index commonly applied in literature.

  8. Large eddy simulations and experiments of nonlinear flow interactions in hybrid rocket combustion

    NASA Astrophysics Data System (ADS)

    Na, Y.; Lee, C.

    2013-03-01

    Nonlinear combustion phenomenon was investigated through an experiment in a hybrid rocket motor. A poly(methyl methacrylate) (PMMA) / gaseous oxygen (GOx) combination was used with several types of disks equipped in a prechamber with the aim of modifying the local turbulent flow. By allowing this disturbance generated in a prechamber to interact with the shedding vortex inherently produced in the main chamber, a possibility of commonly observed nonlinear combustion feature such as DC-shift was analyzed. In a baseline test, a vortex shedding occurs due to the interaction of a main oxidizer flow with the evaporated fuel stream coming out of the surface during the regression process. Among the several types of disks, it turned out that only the disk4 produced the excitation which subsequently suppressed the vortex shedding phenomenon in the main chamber. This descent interaction was reflected in a sudden pressure drop (which may be described as direct current (DC) shift) of about 10 psi in the time history of the pressure during the nominal combustion. The present result with the disk4 suggests the possibility of phase cancellation between the excitation induced by the disk4 and the shedding vortex but much more work should be conducted to extract more accurate correlation of the phase information. In order to understand the baseline flow physics, a compressible large eddy simulation (LES) was conducted with the prescribed wall blowing boundary condition. The result clearly exhibited the existence of vortex shedding phenomenon with a specified frequency. The fact that important flow features of the present computation are quite similar to those obtained with an incompressible assumption in a flat channel suggests that both compressibility and curvature effects do not dominate in the present flow configuration.

  9. Combining experiments and simulations using the maximum entropy principle.

    PubMed

    Boomsma, Wouter; Ferkinghoff-Borg, Jesper; Lindorff-Larsen, Kresten

    2014-02-01

    A key component of computational biology is to compare the results of computer modelling with experimental measurements. Despite substantial progress in the models and algorithms used in many areas of computational biology, such comparisons sometimes reveal that the computations are not in quantitative agreement with experimental data. The principle of maximum entropy is a general procedure for constructing probability distributions in the light of new data, making it a natural tool in cases when an initial model provides results that are at odds with experiments. The number of maximum entropy applications in our field has grown steadily in recent years, in areas as diverse as sequence analysis, structural modelling, and neurobiology. In this Perspectives article, we give a broad introduction to the method, in an attempt to encourage its further adoption. The general procedure is explained in the context of a simple example, after which we proceed with a real-world application in the field of molecular simulations, where the maximum entropy procedure has recently provided new insight. Given the limited accuracy of force fields, macromolecular simulations sometimes produce results that are at not in complete and quantitative accordance with experiments. A common solution to this problem is to explicitly ensure agreement between the two by perturbing the potential energy function towards the experimental data. So far, a general consensus for how such perturbations should be implemented has been lacking. Three very recent papers have explored this problem using the maximum entropy approach, providing both new theoretical and practical insights to the problem. We highlight each of these contributions in turn and conclude with a discussion on remaining challenges. PMID:24586124

  10. Combining Experiments and Simulations Using the Maximum Entropy Principle

    PubMed Central

    Boomsma, Wouter; Ferkinghoff-Borg, Jesper; Lindorff-Larsen, Kresten

    2014-01-01

    A key component of computational biology is to compare the results of computer modelling with experimental measurements. Despite substantial progress in the models and algorithms used in many areas of computational biology, such comparisons sometimes reveal that the computations are not in quantitative agreement with experimental data. The principle of maximum entropy is a general procedure for constructing probability distributions in the light of new data, making it a natural tool in cases when an initial model provides results that are at odds with experiments. The number of maximum entropy applications in our field has grown steadily in recent years, in areas as diverse as sequence analysis, structural modelling, and neurobiology. In this Perspectives article, we give a broad introduction to the method, in an attempt to encourage its further adoption. The general procedure is explained in the context of a simple example, after which we proceed with a real-world application in the field of molecular simulations, where the maximum entropy procedure has recently provided new insight. Given the limited accuracy of force fields, macromolecular simulations sometimes produce results that are at not in complete and quantitative accordance with experiments. A common solution to this problem is to explicitly ensure agreement between the two by perturbing the potential energy function towards the experimental data. So far, a general consensus for how such perturbations should be implemented has been lacking. Three very recent papers have explored this problem using the maximum entropy approach, providing both new theoretical and practical insights to the problem. We highlight each of these contributions in turn and conclude with a discussion on remaining challenges. PMID:24586124

  11. Simulations of MATROSHKA experiments at ISS using PHITS

    NASA Astrophysics Data System (ADS)

    Puchalska, Monika; Sihver, L.; Sato, T.; Berger, T.; Reitz, G.

    Concerns about the biological effects of space radiation are increasing rapidly due to the per-spective of long-duration manned missions, both in relation to the International Space Station (ISS) and to manned interplanetary missions to Moon and Mars in the future. As a prepara-tion for these long duration space missions it is important to ensure an excellent capability to evaluate the impact of space radiation on human health in order to secure the safety of the astronauts/cosmonauts and minimize their risks. It is therefore necessary to measure the radi-ation load on the personnel both inside and outside the space vehicles and certify that organ and tissue equivalent doses can be simulated as accurate as possible. In this paper we will present simulations using the three-dimensional Monte Carlo Particle and Heavy Ion Transport code System (PHITS) of long term dose measurements performed with the ESA supported ex-periment MATROSHKA (MTR), which is an anthropomorphic phantom containing over 6000 radiation detectors, mimicking a human head and torso. The MTR experiment, led by the German Aerospace Center (DLR), was launched in January 2004 and has measured the ab-sorbed dose from space radiation both inside and outside the ISS. In this paper preliminary comparisons of measured and calculated dose and organ doses in the MTR located outside the ISS will be presented. The results confirm previous calculations and measurements which indicate that PHITS is a suitable tool for estimations of dose received from cosmic radiation and when performing shielding design studies of spacecraft. Acknowledgement: The research leading to these results has received funding from the Euro-pean Commission in the frame of the FP7 HAMLET project (Project 218817).

  12. Improved LHCD simulation model and implication for future experiments

    NASA Astrophysics Data System (ADS)

    Shiraiwa, S.; Wallace, G.; Baek, S.; Bonoli, P.; Faust, I.; Parker, R.; Labombard, B.; White, A.; Wukitch, S.

    2015-11-01

    The simulation model for LHCD using the raytracing/FokkerPlanck (GENRAY/CQL3D) code has been improved. Including realistic 2D SOL profiles resolves the discrepancy previously observed at high density (ne > 1 ×1020m-3). Impact of nonlinear interaction in front of the launcher is investigated. It is shown that the distortion of launch n| | spectrum is rather small (up to 10% of injected power). These simulation results suggest that improvement of current drive observed on Alcator C-Mod is indeed caused by realizing preferable SOL plasma profiles. Implication of these results to future experiments will be discussed. In order to minimize edge parasitic losses, realizing high single pass absorption and reducing prompt losses in front of launcher are both crucial. The advantage of LH launch from low field side (LFS) and high field side (HFS) is compared in this regards. A compact LH launcher suitable to test LH wave launch from HFS on a small scale device is designed and its plasma coupling characteristic will be presented. This work was performed on the Alcator C-Mod tokamak, a DoE Office of Science user facility, and is supported by USDoE awards DE-FC02-99ER54512 and DE-AC02-09CH11466.

  13. A horizontal vane radiometer: Experiment, theory, and simulation

    NASA Astrophysics Data System (ADS)

    Wolfe, David; Larraza, Andres; Garcia, Alejandro

    2016-03-01

    The existence of two motive forces on a Crookes radiometer has complicated the investigation of either force independently. The thermal creep shear force in particular has been subject to differing interpretations of the direction in which it acts and its order of magnitude. In this article, we provide a horizontal vane radiometer design which isolates the thermal creep shear force. The horizontal vane radiometer is explored through experiment, kinetic theory, and the Direct Simulation Monte Carlo (DSMC) method. The qualitative agreement between the three methods of investigation is good except for a dependence of the force on the width of the vane even when the temperature gradient is narrower than the vane which is present in the DSMC method results but not in the theory. The experimental results qualitatively resemble the theory in this regard. The quantitative agreement between the three methods of investigation is better than an order of magnitude in the cases examined. The theory is closer to the experimental values for narrow vanes and the simulations are closer to the experimental values for the wide vanes. We find that the thermal creep force acts from the hot side to the cold side of the vane. We also find the peak in the radiometer's angular speed as a function of pressure is explained as much by the behavior of the drag force as by the behavior of the thermal creep force.

  14. Comparison between experiment and simulation for argon inductively coupled plasma

    SciTech Connect

    Gao Fei; Zhao Shuxia; Li Xiaosong; Wang Younian

    2009-11-15

    In order to include the nonlocal characteristics of electrons and investigate the inductively coupled plasma (ICP) resources more completely, we have developed a hybrid Monte Carlo (MC)/fluid hybrid model and calculated the axial and radial distributions of electron density, electron temperature, plasma potential, and electron energy distribution functions (EEDFs) of Ar discharge in a planar ICP. Furthermore, to make the model more practical, we still incorporate the effects of metastable atoms, whose sets of rate coefficients and density are, respectively, calculated through the electron MC part and fluid module. Besides, the corresponding Langmuir probe measurements are used to compare these data to validate the simulated results. Under all the selected discharge powers and pressures, the theoretically simulated and experimentally measured quantity profiles agree reasonably with each other, embodied in the generally identical magnitude ranges and spatial distributions. Furthermore, the interpretations about their detailed differences are given, which are based on the designs of both experimental schematic and model configuration. The analysis implements that the inclusions of electron-electron collision and a neutral density distribution into the hybrid model are likely to improve the comparison between the model predictions and experiment diagnostics. Furthermore, the evolution of plasma parameters and EEDFs with discharge conditions is discussed.

  15. A facility for long-term Mars simulation experiments: the Mars Environmental Simulation Chamber (MESCH).

    PubMed

    Jensen, Lars Liengaard; Merrison, Jonathan; Hansen, Aviaja Anna; Mikkelsen, Karina Aarup; Kristoffersen, Tommy; Nørnberg, Per; Lomstein, Bente Aagaard; Finster, Kai

    2008-06-01

    We describe the design, construction, and pilot operation of a Mars simulation facility comprised of a cryogenic environmental chamber, an atmospheric gas analyzer, and a xenon/mercury discharge source for UV generation. The Mars Environmental Simulation Chamber (MESCH) consists of a double-walled cylindrical chamber. The double wall provides a cooling mantle through which liquid N(2) can be circulated. A load-lock system that consists of a small pressure-exchange chamber, which can be evacuated, allows for the exchange of samples without changing the chamber environment. Fitted within the MESCH is a carousel, which holds up to 10 steel sample tubes. Rotation of the carousel is controlled by an external motor. Each sample in the carousel can be placed at any desired position. Environmental data, such as temperature, pressure, and UV exposure time, are computer logged and used in automated feedback mechanisms, enabling a wide variety of experiments that include time series. Tests of the simulation facility have successfully demonstrated its ability to produce temperature cycles and maintain low temperature (down to -140 degrees C), low atmospheric pressure (5-10 mbar), and a gas composition like that of Mars during long-term experiments. PMID:18593229

  16. Infant rats with chronic neonatal isolation experience show decreased extracellular serotonin levels in ventral striatum at baseline and in response to cocaine.

    PubMed

    Kosten, Therese A; Zhang, Xiang Yang; Kehoe, Priscilla

    2004-08-18

    Previously, we demonstrated that the early life stress of neonatal isolation enhances extracellular dopamine (DA) levels in ventral striatum in response to psychostimulants in infant rats. Yet, neonatal isolation does not alter baseline DA levels. DA levels are affected by serotonin (5-HT) and striatal levels of this transmitter are also enhanced by cocaine. Other early life stresses are reported to alter various 5-HT neural systems. Thus, the purpose of this study is to test whether neonatal isolation alters ventral striatal 5-HT levels at baseline or in response to cocaine. Litters were subjected to neonatal isolation (1-h individual isolation/day on postnatal days 2-9) or to non-handled conditions and pups assigned to one of three cocaine doses (0, 2.5, or 5.0 mg/kg) groups. On postnatal day 10, probes were implanted in the ventral striatum. Dialysate samples obtained over a 60-min baseline period and for 120 min post cocaine injections were assessed for levels of 5-HT and its metabolite, 5-HIAA. ISO decreased ventral striatal 5-HT levels at baseline and after cocaine administration but did not alter 5-HIAA levels. These data add to the literature on the immediate effects of early life stress on 5-HT systems by showing alterations in the ventral striatal system. Because serotonergic effects in this neural area are associated with reward and with emotion and affect regulation, the results of this study suggest that early life stress may be a risk factor for addiction and other psychiatric disorders. PMID:15283991

  17. Helium analysis from the DHCE-1 simulation experiment

    NASA Astrophysics Data System (ADS)

    Smith, Dale L.; Matsui, H.

    2002-12-01

    The combined effects of high helium transmutation rates with the displacement damage produced by high energy fusion neutrons remains the key issues in the evaluation of the performance and lifetime limits of candidate vanadium alloys for fusion first-wall structure applications. A dynamic helium charging experiment (DHCE) has been developed as a unique method for investigating the effects of fusion-relevant helium generation rates on the properties of vanadium alloys irradiated in a fission reactor neutron spectrum. In this simulation, decay of tritium in the vanadium alloy to helium during fission reactor irradiation is used to provide constant He/displacement damage ratios characteristic of a fusion neutron environment. A proof-of-principle experiment (DHCE-1) was conducted in the FFTF reactor. Detailed calculations of the predicted helium concentrations in unalloyed vanadium and the reference V-4Cr-4Ti alloy included in the DHCE-1 indicate quite good agreement with experimental results and demonstrate the validity of the DHCE technique.

  18. Richtmyer-Meshkov mixing: Modeling and simulation of experiments

    NASA Astrophysics Data System (ADS)

    Denissen, Nicholas; Kurien, Susan

    2015-11-01

    Hydrodynamic instabilities that result from the interaction of a shock-wave with a perturbed interface are known as Richtmyer-Meshkov instabilities (RMI). RMI is important in a wide variety of applications including Inertial Confinement Fusion. Recent experiments at Los Alamos National Laboratory (LANL) have focused on careful measurement of initial conditions and repeated statistical measurements of the instability growth and transition to turbulence. This talk will discuss ongoing efforts to model these experiments using weakly non-linear theoretical models, one dimensional Reynolds-Averaged Navier-Stokes models and three-dimensional Implicit Large Eddy Simulations (ILES). Analysis of the experimental data supplies the initial condition for the theoretical model and the ILES calculations. The effect of different initial conditions and mesh resolutions will be examined in light of interest in international collaboration on an RMI test problem. Comparison of the different models to experimental data will be presented. All calculations are performed in the arbitrary Lagrangian/Eulerian (ALE) code FLAG, developed at LANL. The ALE framework allows us to assess the effects of numerical diffusion on RMI computations by varying the remap strategy.

  19. Numerical simulation of molten silicon flow; comparison with experiment

    NASA Astrophysics Data System (ADS)

    Kakimoto, Koichi; Nicodème, Pierre; Lecomte, Michael; Dupret, François; Crochet, Marcel J.

    1991-12-01

    Numerical simulation containing fluid flow, heat conduction and heat exchange by radiation has been performed using the geometry of a real Czochralski furnace for silicon single crystal growth. The flow velocity fields of molten silicon are obtained from extrapolation of the stream function, which has been newly developed using the velocity boundary layer theory. The calculated flow velocity and particle path are semi-quantitatively identical to the results obtained from X-ray radiography experiment. The calculated value of the characteristic velocity is about 10 -2 m/s. The same order of flow velocity which is obtained from the experiment has been already reported. It has also become clear from a comparison of flow velocities between experimental and calculated results that the order of the volume expansion coefficient of the molten silicon (β) is 10 -4 K -1. The flow was almost axisymmetric and steady for a specific case with low crystal and crucible rotation rates and with a shallow melt. We also found that a flow with larger azimuthal velocity component exists just beneath a crystal, while that with opposite flow direction exists near the crucible wall.

  20. Numerical Simulation of Receptivity for a Transition Experiment

    NASA Technical Reports Server (NTRS)

    Collis, S. Scott; Joslin, R. D. (Technical Monitor)

    2000-01-01

    The cost of fuel to overcome turbulence induced viscous drag on a commercial airplane constitutes a significant fraction of the operating cost of an airline. Achieving laminar flow and maintaining it over a large portion of the wing can significantly reduce the viscous drag, and hence the cost. Design of such laminar-flow-control wings and their practical operation requires the ability to accurately and reliably predict the transition from laminar to turbulent flow. The transition process begins with the conversion of environmental and surface disturbances into the instability waves of the flow by a process called receptivity. The goal of the current research project has been to improve the prediction of transition through a better understanding of the physics of receptivity. The initial objective of this work was to investigate the specific stability and receptivity characteristics of a particular experimental investigation of boundary layer receptivity at NASA Langley. Some simulation results using direct solutions of the linearized Navier-Stokes equations which modeled this experiment where presented in the 1999 APS DFD meeting. However, based on these initial investigations, it became clear that to cover the vast receptivity parameter space required for a practical transition prediction tool, more efficient methods would be required. Thus, the focus of this research was shifted from modeling this particular experiment to formulating and developing new techniques that could efficiently yet accurately predict receptivity for a wide range of disturbance conditions.

  1. Experience producing simulated events for the DZero experiment on the SAM-Grid

    SciTech Connect

    Garzoglio, G.; Terekhov, I.; Snow, J.; Jain, S.; Nishandar, A.; /Texas U., Arlington

    2004-12-01

    Most of the simulated events for the DZero experiment at Fermilab have been historically produced by the ''remote'' collaborating institutions. One of the principal challenges reported concerns the maintenance of the local software infrastructure, which is generally different from site to site. As the understanding of the distributed computing community over distributively owned and shared resources progresses, the adoption of grid technologies to address the production of Monte Carlo events for high energy physics experiments becomes increasingly interesting. SAM-Grid is a software system developed at Fermilab, which integrates standard grid technologies for job and information management with SAM, the data handling system of the DZero and CDF experiments. During the past few months, this grid system has been tailored for the Monte Carlo production of DZero. Since the initial phase of deployment, this experience has exposed an interesting series of requirements to the SAM-Grid services, the standard middleware, the resources and their management and to the analysis framework of the experiment. As of today, the inefficiency due to the grid infrastructure has been reduced to as little as 1%. In this paper, we present our statistics and the ''lessons learned'' in running large high energy physics applications on a grid infrastructure.

  2. Precision surveying using very long baseline interferometry

    NASA Technical Reports Server (NTRS)

    Ryan, J. W.; Clark, T. A.; Coates, R.; Ma, C.; Robertson, D. S.; Corey, B. E.; Counselman, C. C.; Shapiro, I. I.; Wittels, J. J.; Hinteregger, H. F.

    1977-01-01

    Radio interferometry measurements were used to measure the vector baselines between large microwave radio antennas. A 1.24 km baseline in Massachusetts between the 36 meter Haystack Observatory antenna and the 18 meter Westford antenna of Lincoln Laboratory was measured with 5 mm repeatability in 12 separate experiments. Preliminary results from measurements of the 3,928 km baseline between the Haystack antenna and the 40 meter antenna at the Owens Valley Radio Observatory in California are presented.

  3. A Mechanics Baseline Test.

    ERIC Educational Resources Information Center

    Hestenes, David; Wells, Malcolm

    1992-01-01

    Reports the design of the "Mechanics Baseline Test," an instrument to assess students' understandings about concepts in mechanics. Discusses how comparisons of test results with extensive baseline data can be used to evaluate instruction at all levels. Includes a copy of the instrument. (MDH)

  4. Experiments and numerical simulation of mixing under supercritical conditions

    NASA Astrophysics Data System (ADS)

    Schmitt, T.; Rodriguez, J.; Leyva, I. A.; Candel, S.

    2012-05-01

    Supercritical pressure conditions designate a situation where the working fluid pressure is above the critical point. Among these conditions, it is interesting to identify a transcritical range which corresponds to cases where the pressure is above the critical point, but the injection temperature is below the critical value. This situation is of special interest because it raises fundamental issues which have technological relevance in the analysis of flows in liquid rocket engines. This situation is here envisaged by analyzing the behavior of a nitrogen shear coaxial jet comprising an inner stream injected at temperatures close to the critical temperature and a coaxial flow at a higher temperature. Experiments are carried out both in the absence of external modulation and by imposing a large amplitude transverse acoustic field. Real gas large eddy simulations are performed for selected experiments. The combination of experiments and calculations is used to evaluate effects of injector geometry and operating parameters. Calculations retrieve what is observed experimentally when the momentum flux ratio of the outer to the inner stream J= (ρ _eu_e^2)/(ρ _iu_i^2) is varied. Results exhibit the change in flow structure and the development of a recirculation region when this parameter exceeds a critical value. The instantaneous flow patterns for different momentum flux ratios are used in a second stage to characterize the dynamical behavior of the flow in terms of power spectral density of velocity and density fluctuations. Results obtained under acoustic modulation provide insight into mixing enhancement of coaxial streams with a view of its possible consequences in high frequency combustion instabilities. It is shown in particular that the presence of strong acoustic modulations notably reduces the high density jet core length, indicating an increased mixing efficiency. This behavior is more pronounced when the jet is placed at the location of maximum transverse

  5. Comparing Burned and Unburned Forest Conditions Using Simulated Rill Experiments

    NASA Astrophysics Data System (ADS)

    Robichaud, P. R.; Brown, R. E.; Wagenbrenner, J. W.

    2007-12-01

    Despite the dominance of concentrated flow or rill erosion in the erosion processes in disturbed forests, few studies have quantified the effects of different types of forest disturbance on rill erosion. This study quantified the effects of four forest conditions--natural (recently undisturbed), low soil burn severity, high soil burn severity, and skid trails--on rill runoff quantity, runoff velocity, and rill erosion. Simulated rill experiments were conducted at sites in eastern Oregon (Tower Fire) and in northern Washington (North 25 Fire) on forested slopes with granitic and volcanic soils, respectively. The natural and skid trail conditions were established near each burned area in unburned forest. For each rill experiment, concentrated flow was applied at the top of the plot through an energy dissipater at five inflow rates for 12 min each. Runoff was sampled every 2 min and runoff volume and sediment concentration were determined for each sample. The runoff velocity was measured using a dyed calcium chloride solution and two conductivity probes placed a known distance apart. Runoff volume, runoff velocities, and sediment concentrations increased with increasing levels of disturbance. The natural plots had very low runoff rates and sediment concentrations at both the Tower and North 25 sites. The low soil burn severity plots had greater responses than the natural plots, but the responses in the two sites were different as a result of variability in effect of burning and differences in time between burning and the rill experiments. The high soil burn severity and the skid trail plots had the highest runoff ratios, runoff velocities, and sediment concentrations and the responses were similar at both sites. These results suggest that any differences in responses related to soil type or other site factors were masked by the increase in response resulting from the high levels of disturbance.

  6. Cardiovascular model for the simulation of exercise, lower body negative pressure, and tilt experiments

    NASA Technical Reports Server (NTRS)

    Croston, R. C.; Fitzjerrell, D. G.

    1974-01-01

    A mathematical model and digital computer simulation of the human cardiovascular system and its controls have been developed to simulate pulsatile dynamic responses to the cardiovascular experiments of the Skylab missions and to selected physiological stresses of manned space flight. Specific model simulations of the bicycle ergometry, lower body negative pressure, and tilt experiments have been developed and verified for 1-g response by comparison with available experimental data. The zero-g simulations of two Skylab experiments are discussed.

  7. Gas-grain simulation experiment module conceptual design and gas-grain simulation facility breadboard development

    NASA Technical Reports Server (NTRS)

    Zamel, James M.; Petach, Michael; Gat, Nahum; Kropp, Jack; Luong, Christina; Wolff, Michael

    1993-01-01

    This report delineates the Option portion of the Phase A Gas-Grain Simulation Facility study. The conceptual design of a Gas-Grain Simulation Experiment Module (GGSEM) for Space Shuttle Middeck is discussed. In addition, a laboratory breadboard was developed during this study to develop a key function for the GGSEM and the GGSF, specifically, a solid particle cloud generating device. The breadboard design and test results are discussed and recommendations for further studies are included. The GGSEM is intended to fly on board a low earth orbit (LEO), manned platform. It will be used to perform a subset of the experiments planned for the GGSF for Space Station Freedom, as it can partially accommodate a number of the science experiments. The outcome of the experiments performed will provide an increased understanding of the operational requirements for the GGSF. The GGSEM will also act as a platform to accomplish technology development and proof-of-principle experiments for GGSF hardware, and to verify concepts and designs of hardware for GGSF. The GGSEM will allow assembled subsystems to be tested to verify facility level operation. The technology development that can be accommodated by the GGSEM includes: GGSF sample generation techniques, GGSF on-line diagnostics techniques, sample collection techniques, performance of various types of sensors for environmental monitoring, and some off-line diagnostics. Advantages and disadvantages of several LEO platforms available for GGSEM applications are identified and discussed. Several of the anticipated GGSF experiments require the deagglomeration and dispensing of dry solid particles into an experiment chamber. During the GGSF Phase A study, various techniques and devices available for the solid particle aerosol generator were reviewed. As a result of this review, solid particle deagglomeration and dispensing were identified as key undeveloped technologies in the GGSF design. A laboratory breadboard version of a solid

  8. SPAce Readiness Coherent Lidar Experiment: validation of observing system simulations

    NASA Astrophysics Data System (ADS)

    Emmitt, George D.; Miller, Timothy; Kavaya, Michael J.

    1998-12-01

    NASA recently approved a mission to fly a Doppler Wind Lidar on a US Space Shuttle. SPARCLE, managed by Marshall Space Flight Center in Huntsville, AL, is targeted for launch in March 2001. This mission is viewed as a necessary demonstration of a solid state lidar using coherent detection before committing resources to a 3-5 year research or operational mission. While, to many, this shuttle mission is seen as the first step in a series leading to a fully operational wind observing system, to others, it is a chance to validate predictions of performance based upon theoretical models, analyses of airborne and ground-based data and sophisticated observing system simulation experiments. The SPARCLE instrument is a 100 mJ, 6 Hz, diode pumped 2 micron laser with a .25 m telescope using heterodyne mixing in a fiber and an InGaAs detector. A 25 cm silicon wedge scanner will be used in step-stare modes with dwells ranging from 60 seconds to .5 seconds. Pointing knowledge is achieved with a dedicated GPS/INS mounted close to the lidar. NASA's hitchhiker program is providing the instrument enclosures and mission logistics support. An on- board data system in sized to record 80 Gbytes of raw signal from two 400 MHz A/D converters. On-board signal processing will be used to control the frequency of the Master Oscillator. SPARCLE is predicted to have a singleshot backscatter sensitivity near 5 by 10-6 m-1 sr-1. To achieve higher sensitivity, shot accumulation will be employed. Ground-based, 2 micron DWLs have been used to assess the benefits of shot accumulation. Airborne programs like MACAWS have provided good data st for evaluating various sampling strategies and signal processing algorithms. Using these real data to calibrate out simulation models, we can describe when and how well SPARCLE is expected to perform.

  9. Cascade processes in stratified media: experiment and direct numerical simulation.

    NASA Astrophysics Data System (ADS)

    Sibgatullin, Ilias; Brouzet, Christophe; Joubaud, Sylvain; Ermanyuk, Evgeny; Dauxois, Thierry

    2016-04-01

    Internal gravity waves may transfer substantial part of energy in oceans and astrophysical objects, influence the background stratification, and angular momentum. Internal waves can be generated by convection in astrophysical objects, by tidal motion and interaction with orography in oceans. Internal and inertial waves obey similar system of equations. Due to very particular type of dispersive relation and the way internal waves are reflected from surfaces, in confined domains the monochromatic internal waves after sequence of reflections may form closed paths, the "wave attractors" [1]. Presently, linear theory of wave attractors is quite elaborated and a principal interest of research is focused on nonlinear regimes and unstable configurations, overturning events and mixing. We have performed direct numerical simulation of wave attractors which closely reproduces experiments [2] being carried out in Ecole Normal Superior de Lyon (ENS de Lyon). Direct numerical simulation is realized with the help of spectral element approach and code nek5000. Triadic resonance is confirmed as the first instability which appears on the most energetic ray of the attractor at sufficiently large forcing. With further increase of the forcing amplitude the daughter waves also become unstable resulting in a sophisticated cascade process which was first observed experimentally. For very high forcing amplitude interaction of focused waves with the walls results in appearance of small-scale folded structures. Their interaction with principal flow is the subject of further research. 1. Maas, L. R. M. & Lam, F.-P. A., Geometric focusing of internal waves. J. Fluid Mech, 1995,. 300, 1-41 2. Scolan, H., Ermanyuk, E., Dauxois, T., 2013, Physical Review Letters, 110, 234501

  10. Small Arrays for Seismic Intruder Detections: A Simulation Based Experiment

    NASA Astrophysics Data System (ADS)

    Pitarka, A.

    2014-12-01

    Seismic sensors such as geophones and fiber optic have been increasingly recognized as promising technologies for intelligence surveillance, including intruder detection and perimeter defense systems. Geophone arrays have the capability to provide cost effective intruder detection in protecting assets with large perimeters. A seismic intruder detection system uses one or multiple arrays of geophones design to record seismic signals from footsteps and ground vehicles. Using a series of real-time signal processing algorithms the system detects, classify and monitors the intruder's movement. We have carried out numerical experiments to demonstrate the capability of a seismic array to detect moving targets that generate seismic signals. The seismic source is modeled as a vertical force acting on the ground that generates continuous impulsive seismic signals with different predominant frequencies. Frequency-wave number analysis of the synthetic array data was used to demonstrate the array's capability at accurately determining intruder's movement direction. The performance of the array was also analyzed in detecting two or more objects moving at the same time. One of the drawbacks of using a single array system is its inefficiency at detecting seismic signals deflected by large underground objects. We will show simulation results of the effect of an underground concrete block at shielding the seismic signal coming from an intruder. Based on simulations we found that multiple small arrays can greatly improve the system's detection capability in the presence of underground structures. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344

  11. Modelling and simulating generic RNA-Seq experiments with the flux simulator

    PubMed Central

    Griebel, Thasso; Zacher, Benedikt; Ribeca, Paolo; Raineri, Emanuele; Lacroix, Vincent; Guigó, Roderic; Sammeth, Michael

    2012-01-01

    High-throughput sequencing of cDNA libraries constructed from cellular RNA complements (RNA-Seq) naturally provides a digital quantitative measurement for every expressed RNA molecule. Nature, impact and mutual interference of biases in different experimental setups are, however, still poorly understood—mostly due to the lack of data from intermediate protocol steps. We analysed multiple RNA-Seq experiments, involving different sample preparation protocols and sequencing platforms: we broke them down into their common—and currently indispensable—technical components (reverse transcription, fragmentation, adapter ligation, PCR amplification, gel segregation and sequencing), investigating how such different steps influence abundance and distribution of the sequenced reads. For each of those steps, we developed universally applicable models, which can be parameterised by empirical attributes of any experimental protocol. Our models are implemented in a computer simulation pipeline called the Flux Simulator, and we show that read distributions generated by different combinations of these models reproduce well corresponding evidence obtained from the corresponding experimental setups. We further demonstrate that our in silico RNA-Seq provides insights about hidden precursors that determine the final configuration of reads along gene bodies; enhancing or compensatory effects that explain apparently controversial observations can be observed. Moreover, our simulations identify hitherto unreported sources of systematic bias from RNA hydrolysis, a fragmentation technique currently employed by most RNA-Seq protocols. PMID:22962361

  12. Indentation experiments and simulation of ovine bone using a viscoelastic-plastic damage model

    PubMed Central

    Zhao, Yang; Wu, Ziheng; Turner, Simon; MacLeay, Jennifer; Niebur, Glen L.; Ovaert, Timothy C.

    2015-01-01

    Indentation methods have been widely used to study bone at the micro- and nanoscales. It has been shown that bone exhibits viscoelastic behavior with permanent deformation during indentation. At the same time, damage due to microcracks is induced due to the stresses beneath the indenter tip. In this work, a simplified viscoelastic-plastic damage model was developed to more closely simulate indentation creep data, and the effect of the model parameters on the indentation curve was investigated. Experimentally, baseline and 2-year postovariectomized (OVX-2) ovine (sheep) bone samples were prepared and indented. The damage model was then applied via finite element analysis to simulate the bone indentation data. The mechanical properties of yielding, viscosity, and damage parameter were obtained from the simulations. The results suggest that damage develops more quickly for OVX-2 samples under the same indentation load conditions as the baseline data. PMID:26136623

  13. Simulation of Seismic Tunnel Detection Experiments in Heterogeneous Geological Media

    NASA Astrophysics Data System (ADS)

    Sherman, C. S.; Glaser, S. D.; Rector, J.

    2013-12-01

    Detecting covert tunnels and other underground openings is an important yet challenging problem for geophysicists, especially where geological heterogeneity is pronounced. A number of geophysical methods have been employed to solve this problem, each with varying degrees of success. We focus on the near-surface seismic techniques of surface wave backscattering, surface wave attenuation tomography, body wave diffraction imaging, and resonant imaging. We use the elastodynamic wave propagation code E3D to simulate tunnel detection experiments completed at this site for a range of synthetic fractal velocity models. The Black Diamond mine, located near Pittsburg California, is used for the field test of our analysis. Our results show that for the relatively low-frequency surface wave attenuation and backscattering methods, the maximum detectable tunnel depth in a homogenous medium is approximately equal to the wavelength of the probing Rayleigh wave. The higher-frequency body wave diffraction and resonant imaging techniques are able to locate tunnels at greater depths, but require more sophisticated analysis and are prone to greater attenuation losses. As is expected, for large values of heterogeneity amplitude, ɛ, the percent standard deviation from the mean velocity model, the average observed surface wave attenuation signal decreases and the maximum detectable tunnel depth decreases. However, for moderate values of heterogeneity amplitude (ɛ < 3%), the average surface wave attenuation signal increases and the maximum detectable tunnel depth increases. For the body wave diffraction and resonant imaging experiments, as ɛ increases the complexity of the observed signal increases, resulting in more difficult processing and interpretation. The additional scattering attenuation tends to degrade the signals significantly due to their reliance on lower amplitude and higher frequency waves.

  14. The INAF/IAPS Plasma Chamber for ionospheric simulation experiment

    NASA Astrophysics Data System (ADS)

    Diego, Piero

    2016-04-01

    The plasma chamber is particularly suitable to perform studies for the following applications: - plasma compatibility and functional tests on payloads envisioned to operate in the ionosphere (e.g. sensors onboard satellites, exposed to the external plasma environment); - calibration/testing of plasma diagnostic sensors; - characterization and compatibility tests on components for space applications (e.g. optical elements, harness, satellite paints, photo-voltaic cells, etc.); - experiments on satellite charging in a space plasma environment; - tests on active experiments which use ion, electron or plasma sources (ion thrusters, hollow cathodes, field effect emitters, plasma contactors, etc.); - possible studies relevant to fundamental space plasma physics. The facility consists of a large volume vacuum tank (a cylinder of length 4.5 m and diameter 1.7 m) equipped with a Kaufman type plasma source, operating with Argon gas, capable to generate a plasma beam with parameters (i.e. density and electron temperature) close to the values encountered in the ionosphere at F layer altitudes. The plasma beam (A+ ions and electrons) is accelerated into the chamber at a velocity that reproduces the relative motion between an orbiting satellite and the ionosphere (≈ 8 km/s). This feature, in particular, allows laboratory simulations of the actual compression and depletion phenomena which take place in the ram and wake regions around satellites moving through the ionosphere. The reproduced plasma environment is monitored using Langmuir Probes (LP) and Retarding Potential Analyzers (RPA). These sensors can be automatically moved within the experimental space using a sled mechanism. Such a feature allows the acquisition of the plasma parameters all around the space payload installed into the chamber for testing. The facility is currently in use to test the payloads of CSES satellite (Chinese Seismic Electromagnetic Satellite) devoted to plasma parameters and electric field

  15. LABORATORY EXPERIMENTS TO SIMULATE CO2 OCEAN DISPOSAL

    SciTech Connect

    Stephen M. Masutani

    1999-12-31

    This Final Technical Report summarizes the technical accomplishments of an investigation entitled ''Laboratory Experiments to Simulate CO{sub 2} Ocean Disposal'', funded by the U.S. Department of Energy's University Coal Research Program. This investigation responds to the possibility that restrictions on greenhouse gas emissions may be imposed in the future to comply with the Framework Convention on Climate Change. The primary objective of the investigation was to obtain experimental data that can be applied to assess the technical feasibility and environmental impacts of oceanic containment strategies to limit release of carbon dioxide (CO{sub 2}) from coal and other fossil fuel combustion systems into the atmosphere. A number of critical technical uncertainties of ocean disposal of CO{sub 2} were addressed by performing laboratory experiments on liquid CO{sub 2} jet break-up into a dispersed droplet phase, and hydrate formation, under deep ocean conditions. Major accomplishments of this study included: (1) five jet instability regimes were identified that occur in sequence as liquid CO{sub 2} jet disintegration progresses from laminar instability to turbulent atomization; (2) linear regression to the data yielded relationships for the boundaries between the five instability regimes in dimensionless Ohnesorge Number, Oh, and jet Reynolds Number, Re, space; (3) droplet size spectra was measured over the full range of instabilities; (4) characteristic droplet diameters decrease steadily with increasing jet velocity (and increasing Weber Number), attaining an asymptotic value in instability regime 5 (full atomization); and (5) pre-breakup hydrate formation appears to affect the size distribution of the droplet phase primary by changing the effective geometry of the jet.

  16. Multi baseline Grid Software Correlator

    NASA Astrophysics Data System (ADS)

    Moritaka, Kimura; Nakajima, Junichi; Kondo, Tetsuro

    Software VLBI correlation is regarded as a solution for next generation VLBI. With a flexibility of the software correlation programming, appropriate scientific correlations by scientists are possible as well as the post processing. As the first experiment to handle Gbps VLBI data, multi baseline Grid correlator have been developing at CRL. The performance of software correlation adopted multi CPUs, SIMD architectures and Grid computing technology has nearly reached hardware correlator performance.

  17. NASA Earth Observing System Simulator Suite (NEOS3): A Forward Simulation Framework for Observing System Simulation Experiments

    NASA Astrophysics Data System (ADS)

    Niamsuwan, N.; Tanelli, S.; Johnson, M. P.; Jacob, J. C.; Jaruwatanadilok, S.; Oveisgharan, S.; Dao, D.; Simard, M.; Turk, F. J.; Tsang, L.; Liao, T. H.; Chau, Q.

    2014-12-01

    Future Earth observation missions will produce a large volume of interrelated data sets that will help us to cross-calibrate and validate spaceborne sensor measurements. A forward simulator is a crucial tool for examining the quality of individual products as well as resolving discrepancy among related data sets. NASA Earth Observing System Simulator Suite (NEOS3) is a highly customizable forward simulation tool for Earth remote sensing instruments. Its three-stage simulation process converts the 3D geophysical description of the scene being observed to corresponding electromagnetic emission and scattering signatures, and finally to observable parameters as reported by a (passive or active) remote sensing instrument. User-configurable options include selection of models for describing geophysical properties of atmospheric particles and their effects on the signal of interest, selection of wave scattering and propagation models, and activation of simplifying assumptions (trading between computation time and solution accuracy). The next generation of NEOS3, to be released in 2015, will feature additional state-of-the-art electromagnetic scattering models for various types of the Earth's surfaces and ground covers (e.g. layered snowpack, forest, vegetated soil, and sea ice) tailored specifically for missions like GPM and SMAP. To be included in 2015 is dedicated functionalities and interface that facilitate integrating NEOS3 into Observing System Simulation Experiment (OSSE) environments. This new generation of NEOS3 can also utilize high performance computing resources (parallel processing and cloud computing) and can be scaled to handle large or computation intensive problems. This presentation will highlight some notable features of NEOS3. Demonstration of its applications for evaluating new mission concepts, especially in the context of OSSE frameworks will also be presented.

  18. Solution Structures of Rat Amylin Peptide: Simulation, Theory, and Experiment

    PubMed Central

    Reddy, Allam S.; Wang, Lu; Lin, Yu-Shan; Ling, Yun; Chopra, Manan; Zanni, Martin T.; Skinner, James L.; De Pablo, Juan J.

    2010-01-01

    Abstract Amyloid deposits of amylin in the pancreas are an important characteristic feature found in patients with Type-2 diabetes. The aggregate has been considered important in the disease pathology and has been studied extensively. However, the secondary structures of the individual peptide have not been clearly identified. In this work, we present detailed solution structures of rat amylin using a combination of Monte Carlo and molecular dynamics simulations. A new Monte Carlo method is presented to determine the free energy of distinct biomolecular conformations. Both folded and random-coil conformations of rat amylin are observed in water and their relative stability is examined in detail. The former contains an α-helical segment comprised of residues 7–17. We find that at room temperature the folded structure is more stable, whereas at higher temperatures the random-coil structure predominates. From the configurations and weights we calculate the α-carbon NMR chemical shifts, with results that are in reasonable agreement with experiments of others. We also calculate the infrared spectrum in the amide I stretch regime, and the results are in fair agreement with the experimental line shape presented herein. PMID:20141758

  19. Simulated Interactive Research Experiments as Educational Tools for Advanced Science

    NASA Astrophysics Data System (ADS)

    Tomandl, Mathias; Mieling, Thomas; Losert-Valiente Kroon, Christiane M.; Hopf, Martin; Arndt, Markus

    2015-09-01

    Experimental research has become complex and thus a challenge to science education. Only very few students can typically be trained on advanced scientific equipment. It is therefore important to find new tools that allow all students to acquire laboratory skills individually and independent of where they are located. In a design-based research process we have investigated the feasibility of using a virtual laboratory as a photo-realistic and scientifically valid representation of advanced scientific infrastructure to teach modern experimental science, here, molecular quantum optics. We found a concept based on three educational principles that allows undergraduate students to become acquainted with procedures and concepts of a modern research field. We find a significant increase in student understanding using our Simulated Interactive Research Experiment (SiReX), by evaluating the learning outcomes with semi-structured interviews in a pre/post design. This suggests that this concept of an educational tool can be generalized to disseminate findings in other fields.

  20. Simulated Interactive Research Experiments as Educational Tools for Advanced Science.

    PubMed

    Tomandl, Mathias; Mieling, Thomas; Losert-Valiente Kroon, Christiane M; Hopf, Martin; Arndt, Markus

    2015-01-01

    Experimental research has become complex and thus a challenge to science education. Only very few students can typically be trained on advanced scientific equipment. It is therefore important to find new tools that allow all students to acquire laboratory skills individually and independent of where they are located. In a design-based research process we have investigated the feasibility of using a virtual laboratory as a photo-realistic and scientifically valid representation of advanced scientific infrastructure to teach modern experimental science, here, molecular quantum optics. We found a concept based on three educational principles that allows undergraduate students to become acquainted with procedures and concepts of a modern research field. We find a significant increase in student understanding using our Simulated Interactive Research Experiment (SiReX), by evaluating the learning outcomes with semi-structured interviews in a pre/post design. This suggests that this concept of an educational tool can be generalized to disseminate findings in other fields. PMID:26370627

  1. Subsonic jet aeroacoustics: associating experiment, modelling and simulation

    NASA Astrophysics Data System (ADS)

    Jordan, Peter; Gervais, Yves

    2008-01-01

    An overview of jet noise research is presented wherein the principal movements in the field are traced since its beginnings. Particular attention is paid to the evolution of our understanding of what we call a “source mechanism” in free shear flows; to the theoretical, experimental and numerical studies which have nurtured this understanding; and to the currently unresolved conceptual difficulties which render analysis of experimental and numerical data so difficult. As it is clear that accelerated progress in this field of research can be made possible by a more effective synergy between the theoretical, experimental and numerical disciplines—one which draws in particular on the impressive recent progress in experimental and numerical techniques—we endeavour to elucidate the various “source” characteristics identified by these different means of study; the points on which the studies agree or disagree, and the significance of such accord or discord; and, the new analysis possibilities which can now be realised by effectively associating experiment, modelling and simulation.

  2. Simulated Interactive Research Experiments as Educational Tools for Advanced Science

    PubMed Central

    Tomandl, Mathias; Mieling, Thomas; Losert-Valiente Kroon, Christiane M.; Hopf, Martin; Arndt, Markus

    2015-01-01

    Experimental research has become complex and thus a challenge to science education. Only very few students can typically be trained on advanced scientific equipment. It is therefore important to find new tools that allow all students to acquire laboratory skills individually and independent of where they are located. In a design-based research process we have investigated the feasibility of using a virtual laboratory as a photo-realistic and scientifically valid representation of advanced scientific infrastructure to teach modern experimental science, here, molecular quantum optics. We found a concept based on three educational principles that allows undergraduate students to become acquainted with procedures and concepts of a modern research field. We find a significant increase in student understanding using our Simulated Interactive Research Experiment (SiReX), by evaluating the learning outcomes with semi-structured interviews in a pre/post design. This suggests that this concept of an educational tool can be generalized to disseminate findings in other fields. PMID:26370627

  3. CLARREO shortwave observing system simulation experiments of the twenty-first century: Simulator design and implementation

    SciTech Connect

    Feldman, D.R.; Algieri, C.A.; Ong, J.R.; Collins, W.D.

    2011-04-01

    Projected changes in the Earth system will likely be manifested in changes in reflected solar radiation. This paper introduces an operational Observational System Simulation Experiment (OSSE) to calculate the signals of future climate forcings and feedbacks in top-of-atmosphere reflectance spectra. The OSSE combines simulations from the Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report for the NCAR Community Climate System Model (CCSM) with the MODTRAN radiative transfer code to calculate reflectance spectra for simulations of current and future climatic conditions over the 21st century. The OSSE produces narrowband reflectances and broadband fluxes, the latter of which have been extensively validated against archived CCSM results. The shortwave reflectance spectra contain atmospheric features including signals from water vapor, liquid and ice clouds, and aerosols. The spectra are also strongly influenced by the surface bidirectional reflectance properties of predicted snow and sea ice and the climatological seasonal cycles of vegetation. By comparing and contrasting simulated reflectance spectra based on emissions scenarios with increasing projected and fixed present-day greenhouse gas and aerosol concentrations, we find that prescribed forcings from increases in anthropogenic sulfate and carbonaceous aerosols are detectable and are spatially confined to lower latitudes. Also, changes in the intertropical convergence zone and poleward shifts in the subsidence zones and the storm tracks are all detectable along with large changes in snow cover and sea ice fraction. These findings suggest that the proposed NASA Climate Absolute Radiance and Refractivity Observatory (CLARREO) mission to measure shortwave reflectance spectra may help elucidate climate forcings, responses, and feedbacks.

  4. CLARREO shortwave observing system simulation experiments of the twenty-first century: Simulator design and implementation

    NASA Astrophysics Data System (ADS)

    Feldman, Daniel R.; Algieri, Chris A.; Ong, Jonathan R.; Collins, William D.

    2011-05-01

    Projected changes in the Earth system will likely be manifested in changes in reflected solar radiation. This paper introduces an operational Observational System Simulation Experiment (OSSE) to calculate the signals of future climate forcings and feedbacks in top-of-atmosphere reflectance spectra. The OSSE combines simulations from the Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report for the NCAR Community Climate System Model (CCSM) with the MODTRAN radiative transfer code to calculate reflectance spectra for simulations of current and future climatic conditions over the 21st century. The OSSE produces narrowband reflectances and broadband fluxes, the latter of which have been extensively validated against archived CCSM results. The shortwave reflectance spectra contain atmospheric features including signals from water vapor, liquid and ice clouds, and aerosols. The spectra are also strongly influenced by the surface bidirectional reflectance properties of predicted snow and sea ice and the climatological seasonal cycles of vegetation. By comparing and contrasting simulated reflectance spectra based on emissions scenarios with increasing projected and fixed present-day greenhouse gas and aerosol concentrations, we find that prescribed forcings from increases in anthropogenic sulfate and carbonaceous aerosols are detectable and are spatially confined to lower latitudes. Also, changes in the intertropical convergence zone and poleward shifts in the subsidence zones and the storm tracks are all detectable along with large changes in snow cover and sea ice fraction. These findings suggest that the proposed NASA Climate Absolute Radiance and Refractivity Observatory (CLARREO) mission to measure shortwave reflectance spectra may help elucidate climate forcings, responses, and feedbacks.

  5. Non-Brownian diffusion in lipid membranes: Experiments and simulations.

    PubMed

    Metzler, R; Jeon, J-H; Cherstvy, A G

    2016-10-01

    The dynamics of constituents and the surface response of cellular membranes-also in connection to the binding of various particles and macromolecules to the membrane-are still a matter of controversy in the membrane biophysics community, particularly with respect to crowded membranes of living biological cells. We here put into perspective recent single particle tracking experiments in the plasma membranes of living cells and supercomputing studies of lipid bilayer model membranes with and without protein crowding. Special emphasis is put on the observation of anomalous, non-Brownian diffusion of both lipid molecules and proteins embedded in the lipid bilayer. While single component, pure lipid bilayers in simulations exhibit only transient anomalous diffusion of lipid molecules on nanosecond time scales, the persistence of anomalous diffusion becomes significantly longer ranged on the addition of disorder-through the addition of cholesterol or proteins-and on passing of the membrane lipids to the gel phase. Concurrently, experiments demonstrate the anomalous diffusion of membrane embedded proteins up to macroscopic time scales in the minute time range. Particular emphasis will be put on the physical character of the anomalous diffusion, in particular, the occurrence of ageing observed in the experiments-the effective diffusivity of the measured particles is a decreasing function of time. Moreover, we present results for the time dependent local scaling exponent of the mean squared displacement of the monitored particles. Recent results finding deviations from the commonly assumed Gaussian diffusion patterns in protein crowded membranes are reported. The properties of the displacement autocorrelation function of the lipid molecules are discussed in the light of their appropriate physical anomalous diffusion models, both for non-crowded and crowded membranes. In the last part of this review we address the upcoming field of membrane distortion by elongated membrane

  6. Microcomputer Simulated Experiments in the Teaching of Multi-Channel Laser System in an Undergraduate Course.

    ERIC Educational Resources Information Center

    Sing, Lee; Chee, Chia Teck

    1997-01-01

    Describes a simulation done by students in a Year 4 undergraduate physics laboratory course on pulse technology. The course objective was to provide students with experience in computation pulsed electrical circuits and in comparing the computation with experiments. Results showed that the microcomputer simulated experiments made for a more…

  7. Simulation of underwater explosion benchmark experiments with ALE3D

    SciTech Connect

    Couch, R.; Faux, D.

    1997-05-19

    Some code improvements have been made during the course of this study. One immediately obvious need was for more flexibility in the constitutive representation for materials in shell elements. To remedy this situation, a model with a tabular representation of stress versus strain and rate dependent effects was implemented. This was required in order to obtain reasonable results in the IED cylinder simulation. Another deficiency was in the ability to extract and plot variables associated with shell elements. The pipe whip analysis required the development of a scheme to tally and plot time dependent shell quantities such as stresses and strains. This capability had previously existed only for solid elements. Work was initiated to provide the same range of plotting capability for structural elements that exist with the DYNA3D/TAURUS tools. One of the characteristics of these problems is the disparity in zoning required in the vicinity of the charge and bubble compared to that needed in the far field. This disparity can cause the equipotential relaxation logic to provide a less than optimal solution. Various approaches were utilized to bias the relaxation to obtain more optimal meshing during relaxation. Extensions of these techniques have been developed to provide more powerful options, but more work still needs to be done. The results presented here are representative of what can be produced with an ALE code structured like ALE3D. They are not necessarily the best results that could have been obtained. More experience in assessing sensitivities to meshing and boundary conditions would be very useful. A number of code deficiencies discovered in the course of this work have been corrected and are available for any future investigations.

  8. Stellar intensity interferometry: experimental steps toward long-baseline observations

    NASA Astrophysics Data System (ADS)

    LeBohec, Stephan; Adams, Ben; Bond, Isobel; Bradbury, Stella; Dravins, Dainis; Jensen, Hannes; Kieda, David B.; Kress, Derrick; Munford, Edward; Nuñez, Paul D.; Price, Ryan; Ribak, Erez; Rose, Joachim; Simpson, Harold; Smith, Jeremy

    2010-07-01

    Experiments are in progress to prepare for intensity interferometry with arrays of air Cherenkov telescopes. At the Bonneville Seabase site, near Salt Lake City, a testbed observatory has been set up with two 3-m air Cherenkov telescopes on a 23-m baseline. Cameras are being constructed, with control electronics for either off- or online analysis of the data. At the Lund Observatory (Sweden) and in Technion (Israel) and at the University of Utah (USA), laboratory intensity interferometers simulating stellar observations have been set up and experiments are in progress, using various analog and digital correlators, reaching 1.4 ns time resolution, to analyze signals from pairs of laboratory telescopes.

  9. Experiments for comparison of small scale rainfall simulators

    NASA Astrophysics Data System (ADS)

    Iserloh, T.; Ries, J. B.

    2012-04-01

    Small scale portable rainfall simulators are an essential tool in research of recent process dynamics of soil erosion. Such rainfall simulators differ in design, rainfall intensities, rain spectra etc., impeding comparison of the results. Due to different research questions a standardisation of rainfall simulation is not in sight. Nevertheless, the data become progressively important for soil erosion modelling and therefore the basis for decision-makers in application-oriented erosion protection. The project aims at providing a criteria catalogue for estimation of the different simulators as well as the comparability of the results and a uniform calibration procedure for generated rainfall. Within the project "Comparability of simulation results of different rainfall simulators as input data for soil erosion modelling (Deutsche Forschungsgemeinschaft - DFG, Project No. Ri 835/6-1)" many rainfall simulators used by European research groups were compared. The artificially generated rainfall of the rainfall simulators at the Universities Basel, La Rioja, Malaga, Trier, Tübingen, Valencia, Wageningen, Zaragoza and at different Spanish CSIC-institutes (Almeria, Cordoba, Granada, Murcia, Zaragoza) were measured with the same methods (Laser Precipitation Monitor for drop spectra and rain collectors for spatial distribution). The data are very beneficial for improvements of simulators and comparison of simulators and results. Furthermore, they can be used for comparative studies with natural rainfall spectra. A broad range of rainfall data was measured (e.g. intensity: 30 - 149 mmh-1, Christiansen Coefficient for spatial rainfall distribution 61 - 98 %, mean drop diameter 0.375 - 5.0 mm, mean kinetic energy expenditure 25 - 1322 J m-2 h-1, mean kinetic energy per unit area and unit depth of rainfall 4 - 14 J m-2 mm-1). Similarities among the simulators could be found e.g. concerning drop size distributions (maximum drop numbers are reached within the two smallest drop

  10. Coupled Simulations, Ground-Based Experiments and Flight Experiments for Astrodynamics Research

    NASA Astrophysics Data System (ADS)

    Boyce, R.; Brown, M.; Lorrain, P.; Capon, C.; Lambert, A.; Benson, C.; Tuttle, S.; Griffin, D.

    Near-Earth satellites undergo complex and poorly understood interactions with their environment, leading to large uncertainties in predicting orbits and an associated risk of collision with other satellites and with space debris. The nature, evolution and behaviour of the growing cloud of space debris in that environment is even less well understood. Significant effort and expenditure is currently being made by governments in Australia, UK, USA, Europe and elsewhere in space surveillance and tracking, in order to mitigate the risk. However, a major gap exists with respect to the science of in-orbit behaviour. Research is underway in Australia to enable the prediction of the orbits of near-Earth space objects with order(s) of magnitude greater fidelity than currently possible. This is being achieved by coupling together the necessary parts of the puzzle - the physics of rarefied space object “aerodynamics” and the space physics and space weather that affects it - and employing our capabilities in ground-based and in-orbit experiments, ground-based observations and high performance computing to do so. As part of the effort, UNSW Canberra is investing $10M to develop a sustainable university-led program to develop and fly affordable in-orbit missions for space research. In the coming 6 years, we will fly a minimum of four cubesat missions, some in partnership with DSTO, which will include flight experiments for validating Space Situational Awareness astrodynamics simulation and observation capabilities. The flights are underpinned by ground-based experimental research employing space test chambers, advanced diagnostics, and supercomputer simulations that couple DSMC and Particle-in-Cell methods for modelling space object interactions with the ionosphere. This paper will describe the research both underway and planned, with particular emphasis on the coupled numerical/experimental/flight approach.

  11. Gas nitriding of high vanadium steels—experiments and simulations

    NASA Astrophysics Data System (ADS)

    Larsson, Henrik; Ågren, John

    2004-09-01

    Four experimental high vanadium alloys were gas nitrided in an ammonia-nitrogen atmosphere. The microstructure and concentration gradients have been investigated by means of several techniques. The nitriding process has been tentatively simulated using the DICTRA software. A precise process simulation does not seem possible at present; the reason for this is discussed. Instead, bounds for the carbon and nitrogen concentration profiles were obtained by applying different simulation conditions.

  12. The Titan Haze Simulation experiment: laboratory simulation of Titan's atmospheric chemistry at low temperature

    NASA Astrophysics Data System (ADS)

    Sciamma-O'Brien, E.; Contreras, C. S.; Ricketts, C. L.; Salama, F.

    2012-04-01

    In Titan’s atmosphere, a complex organic chemistry between its two main constituents, N2 and CH4, leads to the production of heavy molecules and subsequently to solid organic aerosols. Several instruments onboard Cassini have detected neutral, positively and negatively charged particles and heavy molecules in the ionosphere of Titan[1,2]. In particular, the presence of benzene (C6H6) and toluene (C6H5CH3)[3], which are critical precursors of polycyclic aromatic hydrocarbon (PAH) compounds, suggests that PAHs might play a role in the production of Titan’s aerosols. The Titan Haze Simulation (THS) experiment has been developed at NASA Ames’ Cosmic Simulation facility (COSmIC) to study the chemical pathways that link the simple precursor molecules resulting from the first steps of the N2-CH4 chemistry (C2H2, C2H4, HCN…) to benzene, and to PAHs and nitrogen-containing PAHs (or PANHs) as precursors to the production of solid aerosols. In the THS experiment, Titan’s atmospheric chemistry is simulated by plasma in the stream of a supersonic jet expansion. With this unique design, the gas mixture is cooled to Titan-like temperature (~150K) before inducing the chemistry by plasma discharge. Different gas mixtures containing the first products of Titan’s N2-CH4 chemistry but also much heavier molecules like PAHs or PANHs can be injected to study specific chemical reactions. The products of the chemistry are detected and studied using two complementary techniques: Cavity Ring Down Spectroscopy[4] and Time-Of-Flight Mass Spectrometry[5]. Thin tholin deposits are also produced in the THS experiment and can be analyzed by Gas Chromatography-Mass Spectrometry (GC-MS) and Scanning Electron Microscopy (SEM). We will present the results of ongoing mass spectrometry studies on the THS experiment using different gas mixtures: N2-CH4, N2-C2H2, N2-C2H4, N2-C2H6, N2-C6H6, and similar mixtures with an N2-CH4 (90:10) mixture instead of pure N2, to study specific pathways

  13. Brownfield Action: An Integrated Environmental Science Simulation Experience for Undergraduates.

    ERIC Educational Resources Information Center

    Kelsey, Ryan

    This paper presents the results of three years of development and evaluation of a CD-ROM/Web hybrid simulation known as Brownfield Action for an introductory environmental science course at an independent college for women in the northeastern United States. Brownfield Action is a simulation that provides a learning environment for developing the…

  14. Observing system simulation experiments at NASA. Goddard Space Flight Center

    NASA Technical Reports Server (NTRS)

    Atlas, R.; Kalnay, E.; Baker, W. E.; Susskind, J.; Reuter, D.; Halem, M.

    1985-01-01

    A series of realistic simulation studies is being conducted as a cooperative effort between the European Centre for Medium Range Weather Forecasts (ECMWF), the National Meteorological Center (NMC), and the Goddard Laboratory for Atmospheres (GLA), to provide a quantitative assessment of the potential impact of future observing systems on large scale numerical weather prediction. A special objective is to avoid the unrealistic character of earlier simulation studies. Following a brief review of previous simulation studies and real data impact tests, the methodology for the current simulation system will be described. Results from an assessment of the realism of the simulation system and of the potential impact of advanced observing systems on numerical weather prediction and preliminary results utilizing this system will be presented at the conference.

  15. ACES: The ASCENDS CarbonHawk Experiment Simulator

    NASA Astrophysics Data System (ADS)

    Obland, M. D.; Prasad, N. S.; Harrison, F. W.; Browell, E. V.; Ismail, S.; Dobler, J. T.; Moore, B.; Zaccheo, T.; Campbell, J.; Chen, S.; Cleckner, C. S.; DiJoseph, M.; Little, A.; Notari, A.; Refaat, T. F.; Rosenbaum, D.; Vanek, M. D.; Bender, J.; Braun, M.; Chavez-Pirson, A.; Neal, M.; Rayner, P. J.; Rosiewicz, A.; Shure, M.; Welch, W.

    2012-12-01

    The ASCENDS CarbonHawk Experiment Simulator (ACES) is a NASA Langley Research Center project funded by NASA's Earth Science Technology Office (ESTO) Instrument Incubator Program (IIP) that seeks to advance technologies critical to measuring atmospheric column carbon dioxide (CO2) mixing ratios in support of the NASA Active Sensing of CO2 Emissions over Nights, Days, and Seasons (ASCENDS) mission. The technologies being advanced are: (1) a high bandwidth detector, (2) a multi-aperture telescope assembly, (3) advanced algorithms for cloud and aerosol discrimination, and (4) high-efficiency, multiple-amplifier CO2 and O2 laser transmitters. The instrument architecture will be developed to operate on a high-altitude aircraft and will be directly scalable to meet the ASCENDS mission requirements. These technologies are viewed as critical towards developing an airborne simulator and eventual spaceborne instrument with lower size, mass, and power consumption, and improved performance. The detector effort will improve the existing detector subsystem by increasing its bandwidth to a goal of 5 MHz, reducing its overall mass from 18 lbs to <10 lbs, and stretching the duration of autonomous, service-free operation periods from 4 hrs to >24 hrs. The development goals are to permit higher laser modulation rates, which provides greater flexibility for implementing thin-cloud discrimination algorithms as well as improving range resolution and error reduction, and to enable long flights on a high-altitude unmanned aerial vehicle (UAV). The telescope development consists of a three-telescope design built for the constraints of the Global Hawk aircraft. This task addresses the ability of multiple smaller telescopes to provide equal or greater collection efficiency compared with a single larger telescope with a reduced impact on launch mass and cost. The telescope assembly also integrates fiber-coupled transmit collimators for all of the laser transmitters and fiber-coupled optical

  16. Results of NASA/FAA ground and flight simulation experiments concerning helicopter IFR airworthiness criteria

    NASA Technical Reports Server (NTRS)

    Lebacqz, J. V.; Chen, R. T. N.; Gerdes, R. M.; Weber, J. M.; Forrest, R. D.

    1982-01-01

    A sequence of ground and flight simulation experiments was conducted to investigate helicopter instrument-flight-rules airworthiness criteria. The first six of these experiments and major results are summarized. Five of the experiments were conducted on large-amplitude motion base simulators. The NASA-Army V/STOLAND UH-1H variable-stability helicopter was used in the flight experiment. Artificial stability and control augmentation, longitudinal and lateral control, and in pitch and roll attitude augmentation were investigated.

  17. Hyperthermal atomic oxygen source for near-space simulation experiments

    SciTech Connect

    Dodd, James A.; Baker, Paul M.; Hwang, Eunsook S.; Sporleder, David; Stearns, Jaime A.; Chambreau, Steven D.; Braunstein, Matthew; Conforti, Patrick F.

    2009-09-15

    A hyperthermal atomic oxygen (AO) beam facility has been developed to investigate the collisions of high-velocity AO atoms with vapor-phase counterflow. Application of 4.5 kW, 2.4 GHz microwave power in the source chamber creates a continuous discharge in flowing O{sub 2} gas. The O{sub 2} feedstock is introduced into the source chamber in a vortex flow to constrain the plasma to the center region, with the chamber geometry promoting resonant excitation of the TM{sub 011} mode to localize the energy deposition in the vicinity of the aluminum nitride (AlN) expansion nozzle. The approximately 3500 K environment serves to dissociate the O{sub 2}, resulting in an effluent consisting of 40% AO by number density. Downstream of the nozzle, a silicon carbide (SiC) skimmer selects the center portion of the discharge effluent, prior to the expansion reaching the first shock front and rethermalizing, creating a beam with a derived 2.5 km s{sup -1} velocity. Differential pumping of the skimmer chamber, an optional intermediate chamber and reaction chamber maintains a reaction chamber pressure in the mid-10{sup -6} to mid-10{sup -5} Torr range. The beam has been characterized with regard to total AO beam flux, O{sub 2} dissociation fraction, and AO spatial profile using time-of-flight mass spectrometric and Kapton-H erosion measurements. A series of reactions AO+C{sub n}H{sub 2n} (n=2-4) has been studied under single-collision conditions using mass spectrometric product detection, and at higher background pressure detecting dispersed IR emissions from primary and secondary products using a step-scan Michelson interferometer. In a more recent AO crossed-beam experiment, number densities and predicted IR emission intensities have been modeled using the direct simulation Monte Carlo technique. The results have been used to guide the experimental conditions. IR emission intensity predictions are compared to detected signal levels to estimate absolute reaction cross sections.

  18. Hyperthermal atomic oxygen source for near-space simulation experiments.

    PubMed

    Dodd, James A; Baker, Paul M; Hwang, Eunsook S; Sporleder, David; Stearns, Jaime A; Chambreau, Steven D; Braunstein, Matthew; Conforti, Patrick F

    2009-09-01

    A hyperthermal atomic oxygen (AO) beam facility has been developed to investigate the collisions of high-velocity AO atoms with vapor-phase counterflow. Application of 4.5 kW, 2.4 GHz microwave power in the source chamber creates a continuous discharge in flowing O(2) gas. The O(2) feedstock is introduced into the source chamber in a vortex flow to constrain the plasma to the center region, with the chamber geometry promoting resonant excitation of the TM(011) mode to localize the energy deposition in the vicinity of the aluminum nitride (AlN) expansion nozzle. The approximately 3500 K environment serves to dissociate the O(2), resulting in an effluent consisting of 40% AO by number density. Downstream of the nozzle, a silicon carbide (SiC) skimmer selects the center portion of the discharge effluent, prior to the expansion reaching the first shock front and rethermalizing, creating a beam with a derived 2.5 km s(-1) velocity. Differential pumping of the skimmer chamber, an optional intermediate chamber and reaction chamber maintains a reaction chamber pressure in the mid-10(-6) to mid-10(-5) Torr range. The beam has been characterized with regard to total AO beam flux, O(2) dissociation fraction, and AO spatial profile using time-of-flight mass spectrometric and Kapton-H erosion measurements. A series of reactions AO+C(n)H(2n) (n=2-4) has been studied under single-collision conditions using mass spectrometric product detection, and at higher background pressure detecting dispersed IR emissions from primary and secondary products using a step-scan Michelson interferometer. In a more recent AO crossed-beam experiment, number densities and predicted IR emission intensities have been modeled using the direct simulation Monte Carlo technique. The results have been used to guide the experimental conditions. IR emission intensity predictions are compared to detected signal levels to estimate absolute reaction cross sections. PMID:19791929

  19. Status of the NASA GMAO Observing System Simulation Experiment

    NASA Technical Reports Server (NTRS)

    Prive, Nikki C.; Errico, Ronald M.

    2014-01-01

    An Observing System Simulation Experiment (OSSE) is a pure modeling study used when actual observations are too expensive or difficult to obtain. OSSEs are valuable tools for determining the potential impact of new observing systems on numerical weather forecasts and for evaluation of data assimilation systems (DAS). An OSSE has been developed at the NASA Global Modeling and Assimilation Office (GMAO, Errico et al 2013). The GMAO OSSE uses a 13-month integration of the European Centre for Medium- Range Weather Forecasts 2005 operational model at T511/L91 resolution for the Nature Run (NR). Synthetic observations have been updated so that they are based on real observations during the summer of 2013. The emulated observation types include AMSU-A, MHS, IASI, AIRS, and HIRS4 radiance data, GPS-RO, and conventional types including aircraft, rawinsonde, profiler, surface, and satellite winds. The synthetic satellite wind observations are colocated with the NR cloud fields, and the rawinsondes are advected during ascent using the NR wind fields. Data counts for the synthetic observations are matched as closely as possible to real data counts, as shown in Figure 2. Errors are added to the synthetic observations to emulate representativeness and instrument errors. The synthetic errors are calibrated so that the statistics of observation innovation and analysis increments in the OSSE are similar to the same statistics for assimilation of real observations, in an iterative method described by Errico et al (2013). The standard deviations of observation minus forecast (xo-H(xb)) are compared for the OSSE and real data in Figure 3. The synthetic errors include both random, uncorrelated errors, and an additional correlated error component for some observational types. Vertically correlated errors are included for conventional sounding data and GPS-RO, and channel correlated errors are introduced to AIRS and IASI (Figure 4). HIRS, AMSU-A, and MHS have a component of horizontally

  20. Transportation Baseline Schedule

    SciTech Connect

    Fawcett, Ricky Lee; John, Mark Earl

    2000-01-01

    The “1999 National Transportation Program - Transportation Baseline Report” presents data that form a baseline to enable analysis and planning for future Department of Energy (DOE) Environmental Management (EM) waste/material transportation. The companion “1999 Transportation ‘Barriers’ Analysis” analyzes the data and identifies existing and potential problems that may prevent or delay transportation activities based on the data presented. The “1999 Transportation Baseline Schedule” (this report) uses the same data to provide an overview of the transportation activities of DOE EM waste/materials. This report can be used to identify areas where stakeholder interface is needed, and to communicate to stakeholders the quantity/schedule of shipments going through their area. Potential bottlenecks in the transportation system can be identified; the number of packages needed, and the capacity needed at receiving facilities can be planned. This report offers a visualization of baseline DOE EM transportation activities for the 11 major sites and the “Geologic Repository Disposal” site (GRD).

  1. First Grade Baseline Evaluation

    ERIC Educational Resources Information Center

    Center for Innovation in Assessment (NJ1), 2013

    2013-01-01

    The First Grade Baseline Evaluation is an optional tool that can be used at the beginning of the school year to help teachers get to know the reading and language skills of each student. The evaluation is composed of seven screenings. Teachers may use the entire evaluation or choose to use those individual screenings that they find most beneficial…

  2. Floret Test, Numerical Simulations of the Dent, Comparison with Experiments

    SciTech Connect

    Lefrancois, A.; Cutting, J.; Gagliardi, F.; Tarver, C.; Tran, T.

    2006-02-14

    The Floret test has been developed as a screening test to study the performance of a small amount of HE. Numerical simulations have been performed recently using CTH. The objective of this study is to perform numerical simulations in order to better understand the shock waves interactions, involved in the dent formation. Different 3D wedge configurations have been tested using the Ignition and Growth reactive flow model for the HE receptor with Ls-Dyna.

  3. The impact of baseline trend control on visual analysis of single-case data.

    PubMed

    Mercer, Sterett H; Sterling, Heather E

    2012-06-01

    The impact of baseline trend control on visual analyses of AB intervention graphs was examined with simulated data at various values of baseline trend, autocorrelation, and effect size. Participants included 202 undergraduate students with minimal training in visual analysis and 10 graduate students and faculty with more training and experience in visual analysis. In general, results were similar across both groups of participants. Without statistical adjustments to correct for baseline trend, Type I errors greatly increased as baseline trend increased. With corrections for baseline trend, fewer Type I errors were made. As trend increased, participants made fewer Type II errors on the unadjusted graphs as compared to the graphs with baseline trend control. The greater Type II error rate on adjusted graphs could be an artifact of study design (i.e., participants did not know if baseline trend control had been applied), and the impact of MASAJ on Type II errors needs to be explored in detail prior to more widespread use of the method. Implications for future use of baseline trend control techniques by educational professionals are discussed. PMID:22656080

  4. Integrating molecular dynamics simulations with chemical probing experiments using SHAPE-FIT.

    PubMed

    Kirmizialtin, Serdal; Hennelly, Scott P; Schug, Alexander; Onuchic, Jose N; Sanbonmatsu, Karissa Y

    2015-01-01

    Integration and calibration of molecular dynamics simulations with experimental data remain a challenging endeavor. We have developed a novel method to integrate chemical probing experiments with molecular simulations of RNA molecules by using a native structure-based model. Selective 2'-hydroxyl acylation by primer extension (SHAPE) characterizes the mobility of each residue in the RNA. Our method, SHAPE-FIT, automatically optimizes the potential parameters of the force field according to measured reactivities from SHAPE. The optimized parameter set allows simulations of dynamics highly consistent with SHAPE probing experiments. Such atomistic simulations, thoroughly grounded in experiment, can open a new window on RNA structure-function relations. PMID:25726467

  5. Integrating molecular dynamics simulations with chemical probing experiments using SHAPE-FIT

    PubMed Central

    Kirmizialtin, Serdal; Hennelly, Scott P.; Schug, Alexander; Onuchic, Jose N.; Sanbonmatsu, Karissa Y.

    2016-01-01

    Integration and calibration of molecular dynamics simulations with experimental data remains a challenging endeavor. We have developed a novel method to integrate chemical probing experiments with molecular simulations of RNA molecules by using a native structure-based model. Selective 2’-hydroxyl acylation by primer extension (SHAPE) characterizes the mobility of each residue in the RNA. Our method, SHAPE-FIT, automatically optimizes the potential parameters of the forcefield according to measured reactivities from SHAPE. The optimized parameter set allows simulations of dynamics highly consistent with SHAPE probing experiments. Such atomistic simulations, thoroughly grounded in experiment, can open a new window on RNA structure-function relations. PMID:25726467

  6. Learning Oceanography from a Computer Simulation Compared with Direct Experience at Sea

    ERIC Educational Resources Information Center

    Winn, William; Stahr, Frederick; Sarason, Christian; Fruland, Ruth; Oppenheimer, Peter; Lee, Yen-Ling

    2006-01-01

    Considerable research has compared how students learn science from computer simulations with how they learn from "traditional" classes. Little research has compared how students learn science from computer simulations with how they learn from direct experience in the real environment on which the simulations are based. This study compared two…

  7. The Design and the Formative Evaluation of a Web-Based Course for Simulation Analysis Experiences

    ERIC Educational Resources Information Center

    Tao, Yu-Hui; Guo, Shin-Ming; Lu, Ya-Hui

    2006-01-01

    Simulation output analysis has received little attention comparing to modeling and programming in real-world simulation applications. This is further evidenced by our observation that students and beginners acquire neither adequate details of knowledge nor relevant experience of simulation output analysis in traditional classroom learning. With…

  8. Polymer Brushes under Shear: Molecular Dynamics Simulations Compared to Experiments.

    PubMed

    Singh, Manjesh K; Ilg, Patrick; Espinosa-Marzal, Rosa M; Kröger, Martin; Spencer, Nicholas D

    2015-04-28

    Surfaces coated with polymer brushes in a good solvent are known to exhibit excellent tribological properties. We have performed coarse-grained equilibrium and nonequilibrium molecular dynamics (MD) simulations to investigate dextran polymer brushes in an aqueous environment in molecular detail. In a first step, we determined simulation parameters and units by matching experimental results for a single dextran chain. Analyzing this model when applied to a multichain system, density profiles of end-tethered polymer brushes obtained from equilibrium MD simulations compare very well with expectations based on self-consistent field theory. Simulation results were further validated against and correlated with available experimental results. The simulated compression curves (normal force as a function of surface separation) compare successfully with results obtained with a surface forces apparatus. Shear stress (friction) obtained via nonequilibrium MD is contrasted with nanoscale friction studies employing colloidal-probe lateral force microscopy. We find good agreement in the hydrodynamic regime and explain the observed leveling-off of the friction forces in the boundary regime by means of an effective polymer-wall attraction. PMID:25830715

  9. Developing scintillation light readout simulation for the SBND experiment

    NASA Astrophysics Data System (ADS)

    Garcia-Gamez, D.

    2016-01-01

    Detection of scintillation light can play several important roles in LArTPCs. Increased collection efficiency could result in the improvement of time, energy, and position resolution. The SBND collaboration is developing detailed MC simulations to study the performance of different types of light systems in the LArSoft framework. Due to the vast number of photons typically produced in neutrino physics events, a full optical simulation becomes extremely hard to run on reasonable time scales. I will describe how the SBND simulation tackles these problems and its current status for two of the light detection systems considered by SBND: (i) a traditional TPB-coated PMT based system and (ii) a system based on TPB-coated reflector foils to increase collection efficiency without increasing the number of photodetectors.

  10. Reflectance confocal microscopy of red blood cells: simulation and experiment

    PubMed Central

    Zeidan, Adel; Yelin, Dvir

    2015-01-01

    Measuring the morphology of red blood cells is important for clinical diagnosis, providing valuable indications on a patient’s health. In this work, we have simulated the appearance of normal red blood cells under a reflectance confocal microscope and discovered unique relations between the morphological parameters and the resulting characteristic interference patterns of the cell. The simulation results showed good agreement with in vitro reflectance confocal images of red blood cells, acquired using spectrally encoded flow cytometry that imaged the cells in a linear flow without artificial staining. By matching the simulated patterns to confocal images of the cells, this method could be used for measuring cell morphology in three dimensions and for studying their physiology. PMID:26600999

  11. Validation experiments for LBM simulations of electron beam melting

    NASA Astrophysics Data System (ADS)

    Ammer, Regina; Rüde, Ulrich; Markl, Matthias; Jüchter, Vera; Körner, Carolin

    2014-05-01

    This paper validates three-dimensional (3D) simulation results of electron beam melting (EBM) processes by comparing experimental and numerical data. The physical setup is presented which is discretized by a 3D thermal lattice Boltzmann method (LBM). An experimental process window is used for the validation depending on the line energy injected into the metal powder bed and the scan velocity of the electron beam. In the process window, the EBM products are classified into the categories, porous, good and swelling, depending on the quality of the surface. The same parameter sets are used to generate a numerical process window. A comparison of numerical and experimental process windows shows a good agreement. This validates the EBM model and justifies simulations for future improvements of the EBM processes. In particular, numerical simulations can be used to explain future process window scenarios and find the best parameter set for a good surface quality and dense products.

  12. Safety Performance of Airborne Separation: Preliminary Baseline Testing

    NASA Technical Reports Server (NTRS)

    Consiglio, Maria C.; Hoadley, Sherwood T.; Wing, David J.; Baxley, Brian T.

    2007-01-01

    The Safety Performance of Airborne Separation (SPAS) study is a suite of Monte Carlo simulation experiments designed to analyze and quantify safety behavior of airborne separation. This paper presents results of preliminary baseline testing. The preliminary baseline scenario is designed to be very challenging, consisting of randomized routes in generic high-density airspace in which all aircraft are constrained to the same flight level. Sustained traffic density is varied from approximately 3 to 15 aircraft per 10,000 square miles, approximating up to about 5 times today s traffic density in a typical sector. Research at high traffic densities and at multiple flight levels are planned within the next two years. Basic safety metrics for aircraft separation are collected and analyzed. During the progression of experiments, various errors, uncertainties, delays, and other variables potentially impacting system safety will be incrementally introduced to analyze the effect on safety of the individual factors as well as their interaction and collective effect. In this paper we report the results of the first experiment that addresses the preliminary baseline condition tested over a range of traffic densities. Early results at five times the typical traffic density in today s NAS indicate that, under the assumptions of this study, airborne separation can be safely performed. In addition, we report on initial observations from an exploration of four additional factors tested at a single traffic density: broadcast surveillance signal interference, extent of intent sharing, pilot delay, and wind prediction error.

  13. SIMPLEX: simulator and postprocessor for free-electron laser experiments

    PubMed Central

    Tanaka, Takashi

    2015-01-01

    SIMPLEX is a computer program developed for simulating the amplification process of free-electron lasers (FELs). It numerically solves the so-called FEL equations describing the evolution of the radiation field and growth of microbunching while the electron beam travels along the undulator. In order to reduce the numerical cost, the FEL equations have been reduced to more convenient forms for numerical implementation by applying reasonable approximations. SIMPLEX is equipped with a postprocessor to facilitate the retrieval of desired information from the simulation results, which is crucial for practical applications such as designing the beamline and analyzing the experimental results. PMID:26289287

  14. Water vapor permeabilities through polymers: diffusivities from experiments and simulations

    NASA Astrophysics Data System (ADS)

    Seethamraju, Sindhu; Chandrashekarapura Ramamurthy, Praveen; Madras, Giridhar

    2014-09-01

    This study experimentally determines water vapor permeabilities, which are subsequently correlated with the diffusivities obtained from simulations. Molecular dynamics (MD) simulations were used for determining the diffusion of water vapor in various polymeric systems such as polyethylene, polypropylene, poly (vinyl alcohol), poly (vinyl acetate), poly (vinyl butyral), poly (vinylidene chloride), poly (vinyl chloride) and poly (methyl methacrylate). Cavity ring down spectroscopy (CRDS) based methodology has been used to determine the water vapor transmission rates. These values were then used to calculate the diffusion coefficients for water vapor through these polymers. A comparative analysis is provided for diffusivities calculated from CRDS and MD based results by correlating the free volumes.

  15. Experiment vs simulation RT WFNDEC 2014 benchmark: CIVA results

    SciTech Connect

    Tisseur, D. Costin, M. Rattoni, B. Vienne, C. Vabre, A. Cattiaux, G.; Sollier, T.

    2015-03-31

    The French Atomic Energy Commission and Alternative Energies (CEA) has developed for years the CIVA software dedicated to simulation of NDE techniques such as Radiographic Testing (RT). RT modelling is achieved in CIVA using combination of a determinist approach based on ray tracing for transmission beam simulation and a Monte Carlo model for the scattered beam computation. Furthermore, CIVA includes various detectors models, in particular common x-ray films and a photostimulable phosphor plates. This communication presents the results obtained with the configurations proposed in the World Federation of NDEC 2014 RT modelling benchmark with the RT models implemented in the CIVA software.

  16. Experiment vs simulation RT WFNDEC 2014 benchmark: CIVA results

    NASA Astrophysics Data System (ADS)

    Tisseur, D.; Costin, M.; Rattoni, B.; Vienne, C.; Vabre, A.; Cattiaux, G.; Sollier, T.

    2015-03-01

    The French Atomic Energy Commission and Alternative Energies (CEA) has developed for years the CIVA software dedicated to simulation of NDE techniques such as Radiographic Testing (RT). RT modelling is achieved in CIVA using combination of a determinist approach based on ray tracing for transmission beam simulation and a Monte Carlo model for the scattered beam computation. Furthermore, CIVA includes various detectors models, in particular common x-ray films and a photostimulable phosphor plates. This communication presents the results obtained with the configurations proposed in the World Federation of NDEC 2014 RT modelling benchmark with the RT models implemented in the CIVA software.

  17. An obstetric simulation experience in an undergraduate nursing curriculum.

    PubMed

    Robertson, Bethany

    2006-01-01

    Educators face the dilemma of conveying didactic information in concise, creative ways that evoke critical thinking. In addition, high patient acuity, coupled with a growing nursing shortage, requires assimilation of didactic knowledge into sound clinical judgment in a timely manner. Human simulation offers a creative teaching modality that allows transference of textbook knowledge into a real-life situation where nursing students can function in their role without untoward effects to their clients. The author illustrates the use of a human birthing simulator, Noelle, in an undergraduate nursing program as a creative and effective teaching strategy. PMID:16601614

  18. SIMPLEX: simulator and postprocessor for free-electron laser experiments.

    PubMed

    Tanaka, Takashi

    2015-09-01

    SIMPLEX is a computer program developed for simulating the amplification process of free-electron lasers (FELs). It numerically solves the so-called FEL equations describing the evolution of the radiation field and growth of microbunching while the electron beam travels along the undulator. In order to reduce the numerical cost, the FEL equations have been reduced to more convenient forms for numerical implementation by applying reasonable approximations. SIMPLEX is equipped with a postprocessor to facilitate the retrieval of desired information from the simulation results, which is crucial for practical applications such as designing the beamline and analyzing the experimental results. PMID:26289287

  19. Life Support Baseline Values and Assumptions Document

    NASA Technical Reports Server (NTRS)

    Anderson, Molly S.; Ewert, Michael K.; Keener, John F.; Wagner, Sandra A.

    2015-01-01

    The Baseline Values and Assumptions Document (BVAD) provides analysts, modelers, and other life support researchers with a common set of values and assumptions which can be used as a baseline in their studies. This baseline, in turn, provides a common point of origin from which many studies in the community may depart, making research results easier to compare and providing researchers with reasonable values to assume for areas outside their experience. With the ability to accurately compare different technologies' performance for the same function, managers will be able to make better decisions regarding technology development.

  20. Transportation Baseline Report

    SciTech Connect

    Fawcett, Ricky Lee; Kramer, George Leroy Jr.

    1999-12-01

    The National Transportation Program 1999 Transportation Baseline Report presents data that form a baseline to enable analysis and planning for future Department of Energy (DOE) Environmental Management (EM) waste and materials transportation. In addition, this Report provides a summary overview of DOE’s projected quantities of waste and materials for transportation. Data presented in this report were gathered as a part of the IPABS Spring 1999 update of the EM Corporate Database and are current as of July 30, 1999. These data were input and compiled using the Analysis and Visualization System (AVS) which is used to update all stream-level components of the EM Corporate Database, as well as TSD System and programmatic risk (disposition barrier) information. Project (PBS) and site-level IPABS data are being collected through the Interim Data Management System (IDMS). The data are presented in appendices to this report.

  1. Apollo experience report: Simulation of manned space flight for crew training

    NASA Technical Reports Server (NTRS)

    Woodling, C. H.; Faber, S.; Vanbockel, J. J.; Olasky, C. C.; Williams, W. K.; Mire, J. L. C.; Homer, J. R.

    1973-01-01

    Through space-flight experience and the development of simulators to meet the associated training requirements, several factors have been established as fundamental for providing adequate flight simulators for crew training. The development of flight simulators from Project Mercury through the Apollo 15 mission is described. The functional uses, characteristics, and development problems of the various simulators are discussed for the benefit of future programs.

  2. Gear Mesh Loss-of-Lubrication Experiments and Analytical Simulation

    NASA Technical Reports Server (NTRS)

    Handschuh, Robert F.; Polly, Joseph; Morales, Wilfredo

    2011-01-01

    An experimental program to determine the loss-of-lubrication (LOL) characteristics of spur gears in an aerospace simulation test facility has been completed. Tests were conducted using two different emergency lubricant types: (1) an oil mist system (two different misted lubricants) and (2) a grease injection system (two different grease types). Tests were conducted using a NASA Glenn test facility normally used for conducting contact fatigue. Tests were run at rotational speeds up to 10000 rpm using two different gear designs and two different gear materials. For the tests conducted using an air-oil misting system, a minimum lubricant injection rate was determined to permit the gear mesh to operate without failure for at least 1 hr. The tests allowed an elevated steady state temperature to be established. A basic 2-D heat transfer simulation has been developed to investigate temperatures of a simulated gear as a function of frictional behavior. The friction (heat generation source) between the meshing surfaces is related to the position in the meshing cycle, the load applied, and the amount of lubricant in the contact. Experimental conditions will be compared to those from the 2-D simulation.

  3. Computer Simulations for Lab Experiences in Secondary Physics

    ERIC Educational Resources Information Center

    Murphy, David Shannon

    2012-01-01

    Physical science instruction often involves modeling natural systems, such as electricity that possess particles which are invisible to the unaided eye. The effect of these particles' motion is observable, but the particles are not directly observable to humans. Simulations have been developed in physics, chemistry and biology that, under certain…

  4. Computer simulations for lab experiences in secondary physics

    NASA Astrophysics Data System (ADS)

    Murphy, David Shannon

    Physical science instruction often involves modeling natural systems, such as electricity that possess particles which are invisible to the unaided eye. The effect of these particles' motion is observable, but the particles are not directly observable to humans. Simulations have been developed in physics, chemistry and biology that, under certain circumstances, have been found to allow students to gain insight into the operation of the systems they model. This study compared the use of a DC circuit simulation, a modified simulation, static graphics, and traditional bulbs and wires to compare gains in DC circuit knowledge as measured by the DIRECT instrument, a multiple choice instrument previously developed to assess DC circuit knowledge. Gender, prior DC circuit knowledge and subsets of DC circuit knowledge of students were also compared. The population (n=166) was comprised of high school freshmen students from an eastern Kentucky public school with a population of 1100 students and followed a quantitative quasi experimental research design. Differences between treatment groups were not statistically significant. Keywords: Simulations, Static Images, Science Education, DC Circuit Instruction, Phet.

  5. Enhancing Lean Manufacturing Learning Experience through Hands-On Simulation

    ERIC Educational Resources Information Center

    Elbadawi, Isam; McWilliams, Douglas L.; Tetteh, Edem G.

    2010-01-01

    Finding appropriate interactive exercises to increase students' learning in technical topic courses is always challenging to educators. In this study, several paper plane hands-on simulation exercises were developed, used, and tested in a lean manufacturing course for beginning college students. A pretest and posttest was used to assess the…

  6. Simulations of MATROSHKA-R experiments at ISS using PHITS

    NASA Astrophysics Data System (ADS)

    Mrazova, Zlata; Sihver, L.; Jadrnickova, I.; Spurny, F.; Sato, T.; Shurshakov, V. A.

    Concerns about the biological effects of space radiation are increasing rapidly due to the per-spective of long-duration manned missions, both in relation to the International Space Station (ISS) and to the planned manned interplanetary missions to Moon and Mars. As a prepara-tion for these long duration space missions it is important to ensure an excellent capability to evaluate the impact of space radiation on human health in order to secure the safety of the astronauts/cosmonauts and minimize their risks. It is therefore necessary to measure the radi-ation load on the personnel both inside and outside the space vehicles and certify that organ and tissue equivalent doses can be simulated as accurate as possible. In this paper we will present results of simulations of long term dose measurement inside the spherical phantom MATROSHKA-R located inside the crew cabin of ISS. Three-dimensional Monte Carlo Particle and Heavy Ion Transport code System (PHITS) has been used for this purpose. The simulation will be also compared with the experimental data measured with thermoluminescence and plastic nuclear track detectors inside and on the surface of the phantom in year 2006; both, absorbed dose and measured LET spectra will be presented. The results confirm previous calculations concerning the measurements performed inside and outside the ISS. It indicates that PHITS is a suitable tool for simulations of the radiation environment, and dose distributions in humans, in space.

  7. Numerical Simulation of the Perrin-Like Experiments

    ERIC Educational Resources Information Center

    Mazur, Zygmunt; Grech, Dariusz

    2008-01-01

    A simple model of the random Brownian walk of a spherical mesoscopic particle in viscous liquids is proposed. The model can be solved analytically and simulated numerically. The analytic solution gives the known Einstein-Smoluchowski diffusion law r[superscript 2] = 2Dt, where the diffusion constant D is expressed by the mass and geometry of a…

  8. The Land of Milk and Honey: Simulating the Immigrant Experience.

    ERIC Educational Resources Information Center

    Mahood, Wayne

    1980-01-01

    Presents details for a simulation game for a secondary social studies unit on immigration. Depending on the card a student holds, he may be allowed into the land of milk and honey, which in this game consists of graham crackers and milk. Discussion questions are included. (KC)

  9. Simulated Game Playing in Law School; An Experiment

    ERIC Educational Resources Information Center

    King, Donald B.

    1974-01-01

    Describes the successful use of six simulated games in a commercial law class of 84 students and discusses teacher and student evaluation of their effectiveness. The six games, three with a legislative setting and three with a court setting, are included. (JT)

  10. Centimeter repeatability of the VLBI estimates of European baselines

    NASA Technical Reports Server (NTRS)

    Rius, Antonio; Zarraoa, Nestor; Sardon, Esther; Ma, Chopo

    1992-01-01

    In the last three years, the European Geodetic Very Long Baseline Interferometry (VLBI) Network has grown to a total of six fixed antennas placed in Germany, Italy, Spain and Sweden, all equipped with the standard geodetic VLBI instrumentation and data recording systems. During this period of time, several experiments have been carried out using this interferometer providing data of very high quality due to the excellent sensitivity and performance of the European stations. The purpose of this paper is to study the consistency of the VLBI geodetic results on the European baselines with respect to the different degrees of freedom in the analysis procedure. Used to complete this study were both real and simulated data sets, two different software packages (OCCAM 3.0 and CALC 7.4/SOLVE), and a variety of data analysis strategies.

  11. Kinetic simulation of direct-drive capsule implosions and its comparison with experiments and radiation hydrodynamic simulation

    NASA Astrophysics Data System (ADS)

    Kwan, Thomas; Le, Ari; Schmitt, Mark; Herrmann, Hans; Batha, Steve

    2015-11-01

    We have carried out simulations of direct-drive capsule implosion experiments conducted on Omega laser facility at the Laboratory of Laser energetics of the University of Rochester. The capsules had a glass shell (SiO2) with D, T, He-3 fills at various proportions. One-dimensional radiation hydrodynamic calculations and kinetic particle/hybrid simulations with LSP were carried out for the post-shot analysis to compare neutron yield, yield ratio, and shell convergence in assessing the effects of plasma kinetic effects. The LSP simulations were initiated with the output from the rad-hydro simulations at the end of the laser-drive. The electrons are treated as a fluid while all the ion species by the kinetic PIC technique. Our LSP simulations clearly showed species separation between the deuterons, tritons and He-3 during the implosion but significantly less after the compression. The neutron yield, gamma bang-time and -width from the LSP simulations compared favorably with experiments. Detail comparison among the kinetic simulations, rad-hydro simulations, and experimental results will be presented. Work performed under the auspices of the US Department of Energy by Los Alamos National Laboratory under Contract No. W-7405-ENG-36.

  12. Space simulation experiments on reaction control system thruster plumes

    NASA Technical Reports Server (NTRS)

    Cassidy, J. F.

    1972-01-01

    A space simulation procedure was developed for studying rocket plume contamination effects using a 5-pound bipropellant reaction control system thruster. Vacuum chamber pressures of 3 x 10 to the minus 5 torr (70 miles altitude) were achieved with the thruster firing in pulse trains consisting of eight pulses (50 msec on, 100 msec off, and seven minutes between pulse trains). The final vacuum was achieved by cooling all vacuum chamber surfaces to liquid helium temperature and by introducing a continuous argon leak of 48 std. cc/sec into the test chamber. An effort was made to simulate propellant system flow dynamics corresponding to actual spacecraft mission use. Fast time response liquid flow rate measurements showed that large variations occurred in the ratio of oxidizer to fuel flow for pulse-on times up to 120 msec. These variations could lead to poor combustion efficiency and the production of contamination.

  13. Neutralizer Hollow Cathode Simulations and Validation with Experiments

    NASA Technical Reports Server (NTRS)

    Mikellides, Ioannis G.; Goebel, Dan M.; Snyder, John S.; Katz, Ira; Herman, Daniel A.

    2009-01-01

    The fidelity of electric propulsion physics-based models depends largely on the validity of their predictions over a range of operating conditions and geometries. In general, increased complexity of the physics requires more extensive comparisons with laboratory data to identify the region(s) that lie outside the validity of the model assumptions and to quantify the uncertainties within its range of application. This paper presents numerical simulations of neutralizer hollow cathodes at various operating conditions and orifice sizes. The simulations were performed using a two-dimensional axisymmetric model that solves numerically a relatively extensive system of conservation laws for the partially-ionized gas in these devices. The results for the plasma are compared directly with Langmuir probe measurements. The computed keeper voltages are also compared with the observed values. Wherever model inputs and/or specific physics of the cathode discharge are uncertain, additional sensitivity calculations have been performed to quantify the uncertainties.

  14. Accelerated growth of calcium silicate hydrates: Experiments and simulations

    SciTech Connect

    Nicoleau, Luc

    2011-12-15

    Despite the usefulness of isothermal calorimetry in cement analytics, without any further computations this brings only little information on the nucleation and growth of hydrates. A model originally developed by Garrault et al. is used in this study in order to simulate hydration curves of cement obtained by calorimetry with different known hardening accelerators. The limited basis set of parameters used in this model, having a physical or chemical significance, is valuable for a better understanding of mechanisms underlying in the acceleration of C-S-H precipitation. Alite hydration in presence of four different types of hardening accelerators was investigated. It is evidenced that each accelerator type plays a specific role on one or several growth parameters and that the model may support the development of new accelerators. Those simulations supported by experimental observations enable us to follow the formation of the C-S-H layer around grains and to extract interesting information on its apparent permeability.

  15. Simulations of beam-wire experiments at RHIC

    SciTech Connect

    Kim, Hyung Jin; Sen, Tanaji; /Fermilab

    2007-06-01

    A weak-strong beam simulation code (BBSIM) is used to study the compensation of long range beam-beam effects by current carrying wires at the Relativistic Heavy Ion Collider. Tune footprints and tune scans of diffusive aperture are presented for various wire separation distances. Beam life time is estimated using the dependence of the transverse diffusion coefficients on initial action. Comparison of the loss rate from tracking with that measured by BNL is presented.

  16. Fundamental problems in porous materials: Experiments & computer simulation

    NASA Astrophysics Data System (ADS)

    Xu, Zhanping

    Porous materials have attracted massive scientific and technological interest because of their extremely high surface-to-volume ratio, molecular tunability in construction, and surface-based applications. Through my PhD work, porous materials were engineered to meet the design in selective binding, self-healing, and energy damping. For example, crystalline MOFs with pore size spanning from a few angstroms to a couple of nanometers were chemically engineered to show 120 times more efficiency in binding of large molecules. In addition, we found building blocks released from those crystals can be further patched back through a healing process at ambient and low temperatures down to -56 °C. When building blocks are replaced with graphenes, ultra-flyweight aerogels with pore size larger than 100 nm were made to delay shock waves. More stable rigid porous metal with larger pores (~um) was also fabricated, and its performance and survivability are under investigation. Aside from experimental studies, we also successfully applied numerical simulations to study the mutual interaction between the nonplanar liquid-solid interface and colloidal particles during the freezing of the colloidal suspensions. Colloidal particles can be either rejected or engulfed by the evolving interface depending on the freezing speed and strength of interface-particle interaction. Our interactive simulation was achieved by programming both simulation module and visualization module on high performance GPU devices.

  17. Status and Operations at the Clouds and the Earth's Radiant Energy System (CERES) Ocean Validation Experiment (COVE) - Also a Baseline Surface Radiation Network (BSRN) Station

    NASA Astrophysics Data System (ADS)

    Fabbri, B. E.; Schuster, G. L.; Denn, F. M.; Rutan, D. A.; Madigan, J. J.; Arduini, R. F.

    2012-12-01

    25 km off the coast of Virginia, a lighthouse structure has been used for scientific measurements for over a decade. The CERES Ocean Validation Experiment (COVE) at Chesapeake Light is involved in several projects and networks. This report focuses on measurements and analysis made over the last 5 years at COVE. Being part of the BSRN network, most of the instruments at COVE are radiometers that measure both downwelling and upwelling flux at visible and infrared wavelengths. Basic meteorological parameters are also monitored. A table will show all the instrumentation and measurements being collected at COVE for the BSRN network as well as other data collections for aerosol, black carbon, total column water vapor and more. The initial motivation for COVE was to serve as a surface validation site for satellites. We compare modeled and actual downwelling shortwave and longwave measurements into 3 different sky scenarios (clear, partly cloudy and cloudy) over a number of years. Results show the best agreement for the clear sky model in both shortwave and longwave, with downwelling longwave correlating and having less mean bias than downwelling shortwave. COVE provides a wide range of measurements over an ocean environment with other examinations including aerosol studies, black carbon analysis and determination of spectral albedos from Multi-Filter Rotating Shadowband Radiometers (MFRSRs). One example displays how we can use these studies and analysis to trace smoke over the COVE site and how it affects our measurements.Chesapeake Light. Home of the Clouds and the Earth's Radiant Energy System (CERES) Ocean Validation Experiment (COVE) ` Location of Chesapeake Light. Home of COVE. 25 kilometers East of Virginia. Coordinates: 36.90 North, 75.71 West

  18. Hydro-thermal experiments and simulations within a granitic fracture

    NASA Astrophysics Data System (ADS)

    Neuville, Amélie; Flekkøy, Eirik; Jørgen Måløy, Knut; Toussaint, Renaud; Galland, Olivier

    2013-04-01

    The porous medium that we consider is a fracture with impermeable walls that have a complex topography. Our study aims at addressing the heat and mass transport which occurs during the injection of cold water into a fracture, initially filled with warm water and embedded in a warm rock. The characterization of such transfers is relevant to, for instance, hydrothermal circulations occurring at depth, or use of temperature measurements as a tracer of flow pathways. The fluid-rock interface separates exclusively-diffusive from advecto-diffusive processes where the water flows, and the heat diffusion is different in the water and rock. We look at the shape of the isotherm lines (in two dimensions) or surfaces (in three dimensions -- 3D) through time, until steady state is reached. We have both numerical and experimental approaches. The numerical simulations are done with a coupled lattice Boltzmann method that solves both the complete Navier-Stokes and advection-diffusion equations in 3D. The experimental setup has been developed in order to adjust the scaling of our simulations and further investigate the complexity of the hydro-thermal exchange. In this setup, an infrared camera and thermistors are used to monitor the temperature in space and time. Water is injected through a partly natural rough fracture: the bottom part is a granitic bloc with a rough wall, and the top part is a flat layer which is transparent in the infrared range. The surface of the granitic bloc has been digitized using a photogrammetry software (MicMac, developed by the French Institut Géographique National). This digitized surface is then transformed into a 3D mask showing void spaces and rock (digitized porous medium), and is used for the 3D hydro-thermal simulations. We will first present a numerical simulation where the geometry of the fracture consists of flat parallel walls perturbed by a single cavity. Then we will present experimental observations of the temperature done using a

  19. A Nitrogen Balance Experiment Using Simulated Urine Samples

    ERIC Educational Resources Information Center

    Sadighi, Mehri; Reichman, Nurit; Wilson, Kaye; Carne, Alan; Thompson, Mary P.

    2006-01-01

    We describe an undergraduate laboratory experiment that combines the advantages of problem-based learning with the need for biochemistry students to become proficient in practical laboratory skills. It also avoids the need to obtain ethical approval for recruiting volunteers and eliminates any possible biosafety issues with the handling and…

  20. Get real: Effects of repeated simulation and emotion on the perceived plausibility of future experiences

    PubMed Central

    Szpunar, Karl K.; Schacter, Daniel L.

    2012-01-01

    People frequently imagine specific interpersonal experiences that might occur in their futures. The present study used a novel experimental paradigm to examine the influence of repeated simulation of future interpersonal experiences on subjective assessments of plausibility for positive, negative, and neutral events. The results demonstrate that repeated simulation increases estimates of plausibility for emotional, but not neutral, future interpersonal experiences. Additional correlational analyses reveal that increases in plausibility for emotional events are associated with concurrent increases in ease of simulation, event detail, and arousal. Implications for daily life and affective disorders such as depression and anxiety are noted. PMID:22686637

  1. Simulations of Ground and Space-Based Oxygen Atom Experiments

    NASA Technical Reports Server (NTRS)

    Minton, T. K.; Cline, J. A.; Braunstein, M.

    2002-01-01

    Fast, pulsed atomic oxygen sources are a key tool in ground-based investigations of spacecraft contamination and surface erosion effects. These technically challenging ground-based studies provide a before and after picture of materials under low-earth-orbit (LEO) conditions. It would be of great interest to track in real time the pulsed flux from the source to the surface sample target and beyond in order to characterize the population of atoms and molecules that actually impact the surface and those that make it downstream to any coincident detectors. We have performed simulations in order to provide such detailed descriptions of these ground-based measurements and to provide an assessment of their correspondence to the actual LEO environment. Where possible we also make comparisons to measured fluxes and erosion yields. To perform the calculations we use a detailed description of a measurement beam and surface geometry based on the W, pulsed apparatus at Montana State University. In this system, a short pulse (on the order of 10 microseconds) of an O/O2 beam impacts a flat sample about 40 cm downstream and slightly displaced &om the beam s central axis. Past this target, at the end of the beam axis is a quadrupole mass spectrometer that measures the relative in situ flux of 0102 to give an overall normalized erosion yield. In our simulations we use the Direct Simulation Monte Carlo (DSMC) method, and track individual atoms within the atomic oxygen pulse. DSMC techniques are typically used to model rarefied (few collision) gas-flows which occur at altitudes above approximately 110 kilometers. These techniques are well suited for the conditions here, and multi-collision effects that can only be treated by this or a similar technique are included. This simulation includes collisions with the surface and among gas atoms that have scattered from the surface. The simulation also includes descriptions of the velocity spread and spatial profiles of the O/O2 beam

  2. Rainfall simulation experiments in ecological and conventional vineyards.

    NASA Astrophysics Data System (ADS)

    Adrian, Alexander; Brings, Christine; Rodrigo Comino, Jesús; Iserloh, Thomas; Ries, Johannes B.

    2015-04-01

    In October 2014, the Trier University started a measurement series, which defines, compares and evaluates the behavior of runoff and soil erosion with different farming productions in vineyards. The research area is located in Kanzem, a traditional wine village in the Saar Valley (Rheinland-Palatinate, Germany). The test fields show different cultivation methods: ecological (with natural vegetation cover under and around the vines) and conventional cultivated rows of wine. By using the small portable rainfall simulator of Trier University it shall be proved if the assumption that there is more runoff and soil erosion in the conventional part than in the ecological part of the tillage system. Rainfall simulations assess the generation of overland flow, soil erosion and infiltration. So, a trend of soil erosion and runoff of the different cultivation techniques are noted. The objective of this work is to compare the geomorphological dynamics of two different tillage systems. Therefore, 30 rainfall simulations plots were evenly distributed on a west exposition hillside with different slope angels (8-25°), vegetation- and stone-covers. In concrete, the plot surface reaches from strongly covered soil across lithoidal surfaces to bare soil often with compacted lanes of typical using machines. In addition, by using the collected substrate, an estimation and distribution of the grain size of the eroded material shall be given. The eroded substrate is compared to soil samples of the test plots. The first results have shown that there is slightly more runoff and soil erosion in the ecological area than on the conventional part of the vineyard.

  3. Tapped granular column dynamics: simulations, experiments and modeling

    NASA Astrophysics Data System (ADS)

    Rosato, A. D.; Zuo, L.; Blackmore, D.; Wu, H.; Horntrop, D. J.; Parker, D. J.; Windows-Yule, C.

    2016-07-01

    This paper communicates the results of a synergistic investigation that initiates our long term research goal of developing a continuum model capable of predicting a variety of granular flows. We consider an ostensibly simple system consisting of a column of inelastic spheres subjected to discrete taps in the form of half sine wave pulses of amplitude a/ d and period τ . A three-pronged approach is used, consisting of discrete element simulations based on linear loading-unloading contacts, experimental validation, and preliminary comparisons with our continuum model in the form of an integro-partial differential equation.

  4. Simulation of photofission experiments at the ELI-NP facility

    NASA Astrophysics Data System (ADS)

    Constantin, P.; Balabanski, D. L.; Cuong, P. V.

    2016-04-01

    An extensive experimental program for the study of photofission will take place at the Extreme Light Infrastructure - Nuclear Physics (ELI-NP) facility, where different actinide targets will be exposed to a brilliant gamma beam to produce fission fragments. We report on the implementation within the Geant4 simulation toolkit of the photofission process, of related background processes, and of extended ionic charge parameterization. These developments are used to evaluate the production rates of photofission fragments and their release efficiency from the actinide targets.

  5. Complexity of precipitation patterns: Comparison of simulation with experiment.

    PubMed

    Polezhaev, A. A.; Muller, S. C.

    1994-12-01

    Numerical simulations show that a simple model for the formation of Liesegang precipitation patterns, which takes into account the dependence of nucleation and particle growth kinetics on supersaturation, can explain not only simple patterns like parallel bands in a test tube or concentric rings in a petri dish, but also more complex structural features, such as dislocations, helices, "Saturn rings," or patterns formed in the case of equal initial concentrations of the source substances. The limits of application of the model are discussed. (c) 1994 American Institute of Physics. PMID:12780140

  6. HCIT Contrast Performance Sensitivity Studies: Simulation Versus Experiment

    NASA Technical Reports Server (NTRS)

    Sidick, Erkin; Shaklan, Stuart; Krist, John; Cady, Eric J.; Kern, Brian; Balasubramanian, Kunjithapatham

    2013-01-01

    Using NASA's High Contrast Imaging Testbed (HCIT) at the Jet Propulsion Laboratory, we have experimentally investigated the sensitivity of dark hole contrast in a Lyot coronagraph for the following factors: 1) Lateral and longitudinal translation of an occulting mask; 2) An opaque spot on the occulting mask; 3) Sizes of the controlled dark hole area. Also, we compared the measured results with simulations obtained using both MACOS (Modeling and Analysis for Controlled Optical Systems) and PROPER optical analysis programs with full three-dimensional near-field diffraction analysis to model HCIT's optical train and coronagraph.

  7. Simulation of Cold Neutron Experiments using GEANT4

    NASA Astrophysics Data System (ADS)

    Frlez, Emil; Hall, Joshua; Root, Melinda; Baessler, Stefan; Pocanic, Dinko

    2013-10-01

    We review the available GEANT4 physics processes for the cold neutrons in the energy range 1-100 meV. We consider the cases of the neutron beam interacting with (i) para- and ortho- polarized liquid hydrogen, (ii) Aluminum, and (iii) carbon tetrachloride (CCl4) targets. Scattering, thermal and absorption cross sections used by GEANT4 and MCNP6 libraries are compared with the National Nuclear Data Center (NNDC) compilation. NPDGamma detector simulation is presented as an example of the implementation of the resulting GEANT4 code. This work is supported by NSF grant PHY-0970013.

  8. Ten years' experience with four cycles of bleomycin, etoposide, doxorubicin, cyclophosphamide, vincristine, prednisone, procarbazine (BEACOPP)-escalated followed by four cycles of baseline-dose BEACOPP in patients with advanced stage Hodgkin lymphoma: a single-center, retrospective study.

    PubMed

    Belada, David; Štěpánková, Pavla; Sýkorová, Alice; Žák, Pavel; Smolej, Lukáš

    2015-07-01

    The HD-9 trial showed that eight cycles of BEACOPP (bleomycin, etoposide, doxorubicin, cyclophosphamide, vincristine, prednisone, procarbazine)-escalated led to significant improvements in response rate, progression-free survival and overall survival over COPP/ABVD (cyclophosphamide, vincristine, prednisone, procarbazine/doxorubicin, bleomycin, vinblastine, dacarbazine) therapy. This monocentric retrospective study was performed to evaluate 10 years of experience with four cycles of BEACOPP-escalated and four cycles of BEACOPP-baseline outside of clinical trials. The outcomes were assessed in 78 patients with newly diagnosed advanced stage Hodgkin lymphoma. A complete response after chemotherapy ± radiotherapy was achieved in 75 patients (96%). At the median follow-up of 74 months, the actuarial 5- and 10-year freedom from treatment failure (FFTF) rates were 91% and 89%, and actuarial 5- and 10-year overall survival rates for the entire group were 93% and 90%, respectively. These results suggest that the combination of escalated and baseline BEACOPP chemotherapy is feasible in routine practice with good efficacy and acceptable toxicity. PMID:25330440

  9. Skylab Medical Experiments Altitude Test (SMEAT)

    NASA Technical Reports Server (NTRS)

    Johnston, R. S. (Compiler)

    1973-01-01

    The Skylab 56-day environment simulation test provided baseline biomedical data on medical experiments to be included in the Skylab program. Also identified are problems in operating life support systems and medical equipment.

  10. Feature Extraction from Simulations and Experiments: Preliminary Results Using a Fluid Mix Problem

    SciTech Connect

    Kamath, C; Nguyen, T

    2005-01-04

    Code validation, or comparing the output of computer simulations to experiments, is necessary to determine which simulation is a better approximation to an experiment. It can also be used to determine how the input parameters in a simulation can be modified to yield output that is closer to the experiment. In this report, we discuss our experiences in the use of image processing techniques for extracting features from 2-D simulations and experiments. These features can be used in comparing the output of simulations to experiments, or to other simulations. We first describe the problem domain and the data. We next explain the need for cleaning or denoising the experimental data and discuss the performance of different techniques. Finally, we discuss the features of interest and describe how they can be extracted from the data. The focus in this report is on extracting features from experimental and simulation data for the purpose of code validation; the actual interpretation of these features and their use in code validation is left to the domain experts.

  11. Structural evolution of protein-biofilms: Simulations and experiments

    PubMed Central

    Schmitt, Y.; Hähl, H.; Gilow, C.; Mantz, H.; Jacobs, K.; Leidinger, O.; Bellion, M.; Santen, L.

    2010-01-01

    The control of biofilm formation is a challenging goal that has not been reached yet in many aspects. One unsolved question is the role of van der Waals forces and another is the importance of mutual interactions between the adsorbing and the adsorbed biomolecules (“critical crowding”). In this study, a combined experimental and theoretical approach is presented, which fundamentally probes both aspects. On three model proteins—lysozyme, α-amylase, and bovine serum albumin—the adsorption kinetics is studied experimentally. Composite substrates are used enabling a separation of the short- and the long-range forces. Although usually neglected, experimental evidence is given for the influence of van der Waals forces on the protein adsorption as revealed by in situ ellipsometry. The three proteins were chosen for their different conformational stabilities in order to investigate the influence of conformational changes on the adsorption kinetics. Monte Carlo simulations are used to develop a model for these experimental results by assuming an internal degree of freedom to represent conformational changes. The simulations also provide data on the distribution of adsorption sites. By in situ atomic force microscopy we can also test this distribution experimentally, which opens the possibility to, e.g., investigate the interactions between adsorbed proteins. PMID:21045923

  12. HEAT TRANSFER EXPERIMENTS AND ANALYSIS OF A SIMULATED HTS CABLE

    SciTech Connect

    Demko, J. A.; Duckworth, R. C.; Gouge, M. J.; Knoll, D.

    2010-01-01

    Long-length high temperature superconducting (HIS) cable projects, over 1 km, are being designed that are cooled by flowing liquid nitrogen. The compact counter-flow cooling arrangement which has the supply and return stream in a single cryostat offers several advantages including smallest space requirement, least heat load, and reduced cost since a return cryostat is not required. One issue in long length HIS cable systems is the magnitude of the heat transfer radially through the cable. It is extremely difficult to instrument an HIS cable in service on the grid with the needed thermometry because of the issues associated with installing thermometers on high voltage components. A 5-meter long test system has been built that simulates a counter-flow cooled, HIS cable using a heated tube to simulate the cable. Measurements of the temperatures in the flow stream and on the tube wall can be made and compared to analysis. These data can be used to benchmark different HIS cable heat transfer and fluid flow analysis approaches.

  13. Heat Transfer Experiments and Analysis of a Simulated HTS

    SciTech Connect

    Demko, Jonathan A; Duckworth, Robert C; Gouge, Michael J; Knoll, David

    2010-01-01

    Long-length high temperature superconducting (HTS) cable projects, over 1 km, are being designed that are cooled by flowing liquid nitrogen. The compact counter-flow cooling arrangement which has the supply and return stream in a single cryostat offers several advantages including smallest space requirement, least heat load, and reduced cost since a return cryostat is not required. One issue in long length HTS cable systems is the magnitude of the heat transfer radially through the cable. It is extremely difficult to instrument an HTS cable in service on the grid with the needed thermometry because of the issues associated with installing thermometers on high voltage components. A 5-meter long test system has been built that simulates a counter-flow cooled, HTS cable using a heated tube to simulate the cable. Measurements of the temperatures in the flow stream and on the tube wall are presented and compared to analysis. These data can be used to benchmark different HTS cable heat transfer and fluid flow analysis approaches.

  14. Micromechanical tests of ion irradiated materials: Atomistic simulations and experiments

    SciTech Connect

    Shin, C.; Jin, H. H.; Kwon, J.

    2012-07-01

    We investigated irradiation effects on Fe-Cr binary alloys by using a nano-indentation combined with a continuous stiffness measurement (CSM) technique. We modeled the nano-indentation test by using a finite element method. We could extract the intrinsic hardness and the yield stress of an irradiation hardened region by using a so-called inverse method. SiC micro-pillars of various sizes were fabricated by mask and inductively coupled plasma etching technique and compressed by using flat punch nano-indentation. Compressive fracture strength showed a clear specimen size effect. Brittle-to-Ductile transition at room temperature was observed as the specimen size decreases. The effect of irradiation on the fracture strength of SiC micro-pillars was evaluated by performing ion irradiation with Si ions. We have performed molecular dynamics simulations of nano-indentation and nano-pillar compression tests. Radiation effect was observed which is found to be due to the interaction of dislocations nucleated by spherical indenter with pre-existing radiation defects (voids). These atomistic simulations are expected to significantly contribute to the investigation of the fundamental deformation mechanism of small scale irradiated materials. (authors)

  15. Electroreflectance of thin-film solar cells: Simulation and experiment

    NASA Astrophysics Data System (ADS)

    Huber, Christian; Krämmer, Christoph; Sperber, David; Magin, Alice; Kalt, Heinz; Hetterich, Michael

    2015-08-01

    Electromodulated reflectance (ER) is a standard characterization method to determine critical points such as the band gap in the band structure of semiconductors. These critical points show up as spectrally narrow features in ER and are typically evaluated using Aspnes's third-derivative functional form. ER spectra of stratified semiconductor systems such as thin-film solar cells, however, are significantly distorted by optical interference due to their layered structure. Furthermore, strong built-in electric fields result in a deviation from the typically assumed low-field conditions. We present here simulations of ER spectra from stratified systems based on transfer matrices using the Franz-Keldysh theory in its general form. For realistic thin-film solar cell conditions, distortions of ER line shapes due to the above-mentioned interferences and strong electric fields appear in the simulations. Furthermore, the results show good agreement with measured ER spectra of a structurally well-characterized Cu (In ,Ga ) Se2 (CIGS) solar cell. Our analysis points out the restrictions on the determination of energetic position and number of critical points from ER spectra of stratified systems.

  16. Hemodynamics of Central Venous Catheters: experiments and simulations

    NASA Astrophysics Data System (ADS)

    Barbour, Michael; McGah, Patrick; Clark, Alicia; Ng, Chin Hei; Gow, Kenneth; Aliseda, Alberto

    2013-11-01

    Central venous catheters (CVC) are used to provide vascular access during hemodialysis in patients with end-stage kidney disease. Despite several advantages and widespread use, CVCs have a high incidence rate of clot formation during the interdialytic phase (48 hrs). In an attempt the prevent clot formation, hospitals routinely administer heparin, an anticoagulant, into the catheter after a dialysis session. It has been reported, however, that up to 40% of the heparin solution will leak into the blood stream during the interdialytic phase, placing the patient at risk for systemic bleeding incidences. The aim of this study is to determine the role that advective-diffusive transport plays in the heparin leaking process. Numerical simulations of heparin convective mass transfer have been conducted, showing that while advective losses may be significant at the tip, previous studies may be overestimating the total amount of heparin leakage. To validate the quantitative prediction from the simulations, P.L.I.F. is used to experimentally measure heparin transport from CVCs placed in an idealized Superior Vena Cava with physically accurate pulsatile flow conditions. Improved understanding of flow near the catheter tip is applied to improve catheter design and heparin locking procedures.

  17. Urban traffic-network performance: flow theory and simulation experiments

    SciTech Connect

    Williams, J.C.

    1986-01-01

    Performance models for urban street networks were developed to describe the response of a traffic network to given travel-demand levels. The three basic traffic flow variables, speed, flow, and concentration, are defined at the network level, and three model systems are proposed. Each system consists of a series of interrelated, consistent functions between the three basic traffic-flow variables as well as the fraction of stopped vehicles in the network. These models are subsequently compared with the results of microscopic simulation of a small test network. The sensitivity of one of the model systems to a variety of network features was also explored. Three categories of features were considered, with the specific features tested listed in parentheses: network topology (block length and street width), traffic control (traffic signal coordination), and traffic characteristics (level of inter-vehicular interaction). Finally, a fundamental issue concerning the estimation of two network-level parameters (from a nonlinear relation in the two-fluid theory) was examined. The principal concern was that of comparability of these parameters when estimated with information from a single vehicle (or small group of vehicles), as done in conjunction with previous field studies, and when estimated with network-level information (i.e., all the vehicles), as is possible with simulation.

  18. Observing System Simulation Experiments to Define Lidar Wind Requirements

    NASA Technical Reports Server (NTRS)

    Atlas, Robert; Einaudi, Franco (Technical Monitor)

    2002-01-01

    Since the advent of meteorological satellites in the 1960's, numerous experiments have been conducted in order to evaluate the impact of these and other data on atmospheric analysis and prediction. Such studies have included both OSE'S and OSSE's. The OSE's were conducted to evaluate the impact of specific observations or classes of observations on analyses and forecasts. Such experiments have been performed for selected types of conventional data and for various satellite data sets as they became available. (See for example the 1989 ECMWF/EUMETSAT workshop proceedings on "The use of satellite data in operational numerical weather prediction" and the references contained therein.) The OSSE's were conducted to evaluate the potential for future observing systems to improve Numerical Weather Prediction (NWP) and to plan for the Global Weather Experiment and more recently for EOS ( [1], [2], [3]). In addition, OSSE's have been run to evaluate trade-offs in the design of observing systems and observing networks ([4], [5]), and to test new methodology for data assimilation ([6]).

  19. Numerical analysis corresponding with experiment in compact beam simulator for heavy ion inertial fusion driver

    NASA Astrophysics Data System (ADS)

    Kikuchi, T.; Sakai, Y.; Komori, T.; Sato, T.; Hasegawa, J.; Horioka, K.; Takahashi, K.; Sasaki, T.; Harada, Nob

    2016-05-01

    Tune depression in a compact beam equipment is estimated, and numerical simulation results are compared with an experimental one for the compact beam simulator in a driver of heavy ion inertial fusion. The numerical simulation with multi-particle tracking is carried out, corresponding to the experimental condition, and the result is discussed with the experimental one. It is expected that the numerical simulation developed in this paper is useful tool to investigate the beam dynamics in the experiment with the compact beam simulator.

  20. The Aqua-Planet Experiment (APE): CONTROL SST Simulation

    NASA Technical Reports Server (NTRS)

    Blackburn, Michael; Williamson, David L.; Nakajima, Kensuke; Ohfuchi, Wataru; Takahashi, Yoshiyuki O.; Hayashi, Yoshi-Yuki; Nakamura, Hisashi; Ishiwatari, Masaki; Mcgregor, John L.; Borth, Hartmut; Wirth, Volkmar; Frank, Helmut; Bechtold, Peter; Wedi, Nils P.; Tomita, Hirofumi; Satoh, Masaki; Zhao, Ming; Held, Isaac M.; Suarez, Max J.; Lee, Myong-In; Watanabe, Masahiro; Kimoto, Masahide; Liu, Yimin; Wang, Zaizhi; Molod, Andrea M.; Rajendran, Kavirajan; Kotoh, Akio; Stratton, Rachel

    2013-01-01

    Climate simulations by 16 atmospheric general circulation models (AGCMs) are compared on an aqua-planet, a water-covered Earth with prescribed sea surface temperature varying only in latitude. The idealised configuration is designed to expose differences in the circulation simulated by different models. Basic features of the aqua-planet climate are characterised by comparison with Earth. The models display a wide range of behaviour. The balanced component of the tropospheric mean flow, and mid-latitude eddy covariances subject to budget constraints, vary relatively little among the models. In contrast, differences in damping in the dynamical core strongly influence transient eddy amplitudes. Historical uncertainty in modelled lower stratospheric temperatures persists in APE.Aspects of the circulation generated more directly by interactions between the resolved fluid dynamics and parameterized moist processes vary greatly. The tropical Hadley circulation forms either a single or double inter-tropical convergence zone (ITCZ) at the equator, with large variations in mean precipitation. The equatorial wave spectrum shows a wide range of precipitation intensity and propagation characteristics. Kelvin mode-like eastward propagation with remarkably constant phase speed dominates in most models. Westward propagation, less dispersive than the equatorial Rossby modes, dominates in a few models or occurs within an eastward propagating envelope in others. The mean structure of the ITCZ is related to precipitation variability, consistent with previous studies.The aqua-planet global energy balance is unknown but the models produce a surprisingly large range of top of atmosphere global net flux, dominated by differences in shortwave reflection by clouds. A number of newly developed models, not optimised for Earth climate, contribute to this. Possible reasons for differences in the optimised models are discussed.The aqua-planet configuration is intended as one component of an

  1. Numerical simulation of the experiment of electrical explosion of aluminum foil

    NASA Astrophysics Data System (ADS)

    Shutov, A. V.

    2015-11-01

    Numerical simulation of the experiment of Korobenko et al (2007 Phys. Rev. B 75 064208) in strongly coupled plasma of aluminum have been fulfilled. The results of numerical simulation and the experiment are compared. It is established that the hydrodynamic flows in the experiment can be assumed one-dimensional. The elastic-plastic effects in the dynamics of aluminum foil are also insignificant. The focus in the modeling is devoted to the study of the dynamics of the thermodynamic states of aluminum and their spatial homogeneity. It is emphasized the strong influence of the thermal conductivity for such experiments.

  2. Experiments and simulation of high current operation at CEBAF

    SciTech Connect

    Merminga, L.; Crawford, K.; Delayen, J.R.; Doolittle, L.; Hovater, C.; Kazimi, R.; Krafft, G.; Reece, C.; Simrock, S.; Tiefenback, M.; Wang, D.X.

    1996-07-01

    The superconducting rf, cw electron accelerator at CEBAF has achieved the design energy of 4 GeV using 5-pass recirculation through a pair of 400 MeV linacs. Stable beam current of 35 {mu}A has been delivered to the Experimental Hall C. The total beam current that has been recirculated so far is 248 {mu}A. Measurements of the performance of the rf control system have been made in both pulsed and cw mode, and a numerical model has been developed which describes the beam-cavity interaction, includes a realistic representation of low level controls, klystron characteristics and microphonic noise. Experimental data and simulation results on transient beam loading, klystron saturation, a new technique for cavity phasing, and heavy beam loading tests are described; in conclusion, an outlook on full current operation is presented.

  3. Neutron Correlations in Special Nuclear Materials, Experiments and Simulations

    SciTech Connect

    Verbeke, J; Dougan, A; Nakae, L; Sale, K; Snyderman, N

    2007-06-05

    Fissile materials emit neutrons with an unmistakable signature that can reveal characteristics of the material. We describe here measurements, simulations, and predicted signals expected and prospects for application of neutron correlation measurement methods to detection of special nuclear materials (SNM). The occurrence of fission chains in SNM can give rise to this distinctive, measurable time correlation signal. The neutron signals can be analyzed to detect the presence and to infer attributes of the SNM and surrounding materials. For instance, it is possible to infer attributes of an assembly containing a few kilograms of uranium, purely passively, using detectors of modest size in a reasonable time. Neutron signals of three radioactive sources are shown to illustrate the neutron correlation and analysis method. Measurements are compared with Monte Carlo calculations of the authenticated sources.

  4. Monte Carlo simulation of the abBA experiment

    NASA Astrophysics Data System (ADS)

    Frlež, Emil

    2004-10-01

    The abBA collaboration proposes to conduct a program of precise measurements of neutron beta decay correlation coefficients a, b, A, and B at a cold neutron beam facility. We have performed studies of the energy and timing response of a pair of silicon detectors. To this end we have compared (i) the industry-standard SIMION 3D 7.0 program, and (ii) a GEANT4-based code with the addition of appropriate adiabatic invariants in simulating the propagation of the decay electrons and protons in the electromagnetic spectrometer. We use these results to examine the systematic effects and to determine the precision with which the physics parameters a, b, A, and B can be extracted in practice.

  5. Clearance gap flow: simulations by discontinuous Galerkin method and experiments

    NASA Astrophysics Data System (ADS)

    Prausová, Helena; Bublík, Ondřej; Vimmr, Jan; Luxa, Martin; Hála, Jindřich

    2015-05-01

    Compressible viscous fluid flow in a narrow gap formed by two parallel plates in distance of 2 mm is investigated numerically and experimentally. Pneumatic and optical methods were used to obtain distribution of static to stagnation pressure ratio along the channel axis and interferograms including the free outflow behind the channel. Modern developing discontinuous Galerkin finite element method is implemented for numerical simulation of the fluid flow. The goal to make progress in knowledge of compressible viscous fluid flow characteristic phenomena in minichannels is satisfied by finding a suitable approach to this problem. Laminar, turbulent and transitional flow regime is examined and a good agreement of experimental and numerical results is achieved using γ - Reθt transition model.

  6. Governance of complex systems: results of a sociological simulation experiment.

    PubMed

    Adelt, Fabian; Weyer, Johannes; Fink, Robin D

    2014-01-01

    Social sciences have discussed the governance of complex systems for a long time. The following paper tackles the issue by means of experimental sociology, in order to investigate the performance of different modes of governance empirically. The simulation framework developed is based on Esser's model of sociological explanation as well as on Kroneberg's model of frame selection. The performance of governance has been measured by means of three macro and two micro indicators. Surprisingly, central control mostly performs better than decentralised coordination. However, results not only depend on the mode of governance, but there is also a relation between performance and the composition of actor populations, which has yet not been investigated sufficiently. Practitioner Summary: Practitioners can gain insights into the functioning of complex systems and learn how to better manage them. Additionally, they are provided with indicators to measure the performance of complex systems. PMID:24456093

  7. Shock Velocity Variations in Supernova Remnant Simulation Experiments

    NASA Astrophysics Data System (ADS)

    Drake, R. P.; Carroll, J. J., III; Smith, T. B.; Reisig, H. N.; Glendinning, S. G.; Estabrook, K.; Remington, B. A.; Wallace, R.; McCray, R.

    1998-11-01

    We are studying the hydrodynamic behavior of a laboratory system that is a good scaled model of young supernova remnants. The hydrodynamic effects are driven by a supersonic flow, produced by the Nova laser. It does this by driving a strong shock, produced by x-ray ablation, out the back of a plastic slab. The ejecta expand, accelerate, cool, and then impact a low-density foam. There the ejecta stagnate and form a reverse shock while driving a strong shock forward through the foam. We observe this hydrodynamic assembly by x-ray radiography. The shock velocities in one case agree with those found by a computer simulation, while in another case they do not. We will report our investigation of this discrepancy. (Work supported by the US Department of Energy under LLNL LDRD-ER Grant No. 97-ERD-022 and by the University of Michigan.)

  8. Mechanical characterisation of Dacron graft: Experiments and numerical simulation.

    PubMed

    Bustos, Claudio A; García-Herrera, Claudio M; Celentano, Diego J

    2016-01-01

    Experimental and numerical analyses focused on the mechanical characterisation of a woven Dacron vascular graft are presented. To that end, uniaxial tensile tests under different orientations have been performed to study the anisotropic behaviour of the material. These tests have been used to adjust the parameters of a hyperelastic anisotropic constitutive model which is applied to predict through numerical simulation the mechanical response of this material in the ring tensile test. The obtained results show that the model used is capable of representing adequately the nonlinear elastic region and, in particular, it captures the progressive increase of the rigidity and the anisotropy due to the stretching of the Dacron. The importance of this research lies in the possibility of predicting the graft׳s mechanical response under generalized loading such as those that occur under physiological conditions after surgical procedures. PMID:26627367

  9. Long-term memory in experiments and numerical simulations of hydrodynamic and magnetohydrodynamic turbulence

    NASA Astrophysics Data System (ADS)

    Mininni, P.; Dmitruk, P.; Odier, P.; Pinton, J.-F.; Plihon, N.; Verhille, G.; Volk, R.; Bourgoin, M.

    2014-05-01

    We analyze time series stemming from experiments and direct numerical simulations of hydrodynamic and magnetohydrodynamic turbulence. Simulations are done in periodic boxes, but with a volumetric forcing chosen to mimic the geometry of the flow in the experiments, the von Kármán swirling flow between two counterrotating impellers. Parameters in the simulations are chosen to (within computational limitations) allow comparisons between the experiments and the numerical results. Conducting fluids are considered in all cases. Two different configurations are considered: a case with a weak externally imposed magnetic field and a case with self-sustained magnetic fields. Evidence of long-term memory and 1/f noise is observed in experiments and simulations, in the case with weak magnetic field associated with the hydrodynamic behavior of the shear layer in the von Kármán flow, and in the dynamo case associated with slow magnetohydrodynamic behavior of the large-scale magnetic field.

  10. Synergy Between Experiments and Simulations in Laser and Beam-Driven Plasma Acceleration and Light Sources

    NASA Astrophysics Data System (ADS)

    Mori, Warren B.

    2015-11-01

    Computer simulations have been an integral part of plasma physics research since the early 1960s. Initially, they provided the ability to confirm and test linear and nonlinear theories in one-dimension. As simulation capabilities and computational power improved, then simulations were also used to test new ideas and applications of plasmas in multi-dimensions. As progress continued, simulations were also used to model experiments. Today computer simulations of plasmas are ubiquitously used to test new theories, understand complicated nonlinear phenomenon, model the full temporal and spatial scale of experiments, simulate parameters beyond the reach of current experiments, and test the performance of new devices before large capital expenditures are made to build them. In this talk I review the progress in simulations in a particular area of plasma physics: plasma based acceleration (PBA). In PBA a short laser pulse or particle beam propagates through long regions of plasma creating plasma wave wakefields on which electrons or positrons surf to high energies. In some cases the wakefields are highly nonlinear, involve three-dimensional effects, and the trajectories of plasma particles cross making it essential that fully kinetic and three-dimensional models are used. I will show how particle-in-cell (PIC) simulations were initially used to propose the basic idea of PBA in one dimension. I will review some of the dramatic progress in the experimental demonstration of PBA and show how this progress was dramatically helped by a synergy between experiments and full-scale multi-dimensional PIC simulations. This will include a review of how the capability of PIC simulation tools has improved. I will also touch on some recent progress on improvements to PIC simulations of PBA and discuss how these improvements may push the synergy further towards real time steering of experiments and start to end modeling of key components of a future linear collider or XFEL based on PBA

  11. Finite Element Simulations to Explore Assumptions in Kolsky Bar Experiments.

    SciTech Connect

    Crum, Justin

    2015-08-05

    The chief purpose of this project has been to develop a set of finite element models that attempt to explore some of the assumptions in the experimental set-up and data reduction of the Kolsky bar experiment. In brief, the Kolsky bar, sometimes referred to as the split Hopkinson pressure bar, is an experimental apparatus used to study the mechanical properties of materials at high strain rates. Kolsky bars can be constructed to conduct experiments in tension or compression, both of which are studied in this paper. The basic operation of the tension Kolsky bar is as follows: compressed air is inserted into the barrel that contains the striker; the striker accelerates towards the left and strikes the left end of the barrel producing a tensile stress wave that propogates first through the barrel and then down the incident bar, into the specimen, and finally the transmission bar. In the compression case, the striker instead travels to the right and impacts the incident bar directly. As the stress wave travels through an interface (e.g., the incident bar to specimen connection), a portion of the pulse is transmitted and the rest reflected. The incident pulse, as well as the transmitted and reflected pulses are picked up by two strain gauges installed on the incident and transmitted bars as shown. By interpreting the data acquired by these strain gauges, the stress/strain behavior of the specimen can be determined.

  12. NUMERICAL SIMULATIONS OF CONVERGING SHOCKS IN PULSED POWER DRIVEN EXPERIMENTS

    SciTech Connect

    R. KANZLEITER; W. ATCHISON; ET AL

    2000-12-01

    The final shot of the current Near Term Liner Experiment (NTLX) series occurred on September 29, 2000. Utilization of a pulsed power source with a standardized liner/target ''cartridge'' produced a uniform implosion to drive hydrodynamic experiments. Diagnostics showed that high quality data of shock propagation can be obtained from pulsed power liner drivers as in the current NTLX series. Very good agreement in calculating shock locations was obtained between the codes used to model the NTLX series, RAGE and RAVEN. RAVEN also accurately predicts liner/target impact as measured by B-Dot probes. Large differences are observed between the calculated and measured positions of converging shock waves even in simple geometrical configurations. Liner/target impact is accurately calculated and similar results are produced for shock velocities in Lucite. RAGE and RAVEN use different hydrodynamic algorithms, yet agree, this focuses current efforts on EOS issues within the outer tin target to resolve discrepancies. Further diagnostics covering shock breakout from the outer tin target and shock propagation shortly thereafter would be highly beneficial.

  13. Results of GEANT simulations and comparison with first experiments at DANCE.

    SciTech Connect

    Reifarth, R.; Bredeweg, T. A.; Browne, J. C.; Esch, E. I.; Haight, R. C.; O'Donnell, J. M.; Kronenberg, A.; Rundberg, R. S.; Ullmann, J. L.; Vieira, D. J.; Wilhelmy, J. B.; Wouters, J. M.

    2003-07-29

    This report describes intensive Monte Carlo simulations carried out to be compared with the results of the first run cycle with DANCE (Detector for Advanced Neutron Capture Experiments). The experimental results were gained during the commissioning phase 2002/2003 with only a part of the array. Based on the results of these simulations the most important items to be improved before the next experiments will be addressed.

  14. Experiments in pilot decision-making during simulated low visibility approaches

    NASA Technical Reports Server (NTRS)

    Curry, R. E.; Lauber, J. K.; Billings, C. E.

    1975-01-01

    A simulation task is reported which incorporates both kinds of variables, informational and psychological, to successfully study pilot decision making behavior in the laboratory. Preliminary experiments in the measurement of decisions and the inducement of stress in simulated low visibility approaches are described.

  15. Ideas in Practice (3): A Simulated Laboratory Experience in Digital Design.

    ERIC Educational Resources Information Center

    Cleaver, Thomas G.

    1988-01-01

    Gives an example of the use of a simplified logic simulator in a logic design course. Discusses some problems in logic design classes, commercially available software, and software problems. Describes computer-aided engineering (CAE) software. Lists 14 experiments in the simulated laboratory and presents students' evaluation of the course. (YP)

  16. Simulations of X-ray Emission from Omega Fill Tube Experiments

    SciTech Connect

    Langer, S; Izumi, N; Dittrich, T; Haan, S

    2006-11-13

    The capsules used in ignition experiments on the National Ignition Facility (NIF) laser will have a layer of frozen DT inside a low-Z shell. Liquid DT will be injected through a narrow fill tube that penetrates the shell and frozen in place. The fill tube is a perturbation on the surface of the capsule and hydrodynamic instabilities will cause this perturbation to grow during an implosion. Experiments to investigate the growth of perturbations due to fill tubes have been carried out on the Omega laser. The goal of these experiments was to validate simulations at Omega energy scales and thus increase confidence in the use of simulations in planning for NIF experiments. Simulations show that the fill tube leads to a jet of shell material that penetrates into the DT fuel. Simulations will be used to pick experimental conditions in which the jet is small enough that it does not significantly reduce the yield of a NIF implosion. This paper compares experiments in which bumps and stalks were used as fill tube surrogates to 2D simulations of x-ray emission from Omega capsule implosions. Experiments and simulations are in reasonable agreement on the size of a bump or stalk required to produce a jet that is visible above the emission from a (nominally) smooth capsule.

  17. Resonant Discharge Simulations; Comparisons with Theory and Experiment

    NASA Astrophysics Data System (ADS)

    Birdsall, C. K.; Bowers, K. J.

    1998-10-01

    Discharges driven at the series resonance frequency have a small input resistance. The voltage drive is small (like Te), and the average plasma potential is low (like 10Te). Such were observed experimentally by Godyak et al. (paper 3C9, IEEE ICOPS, Santa Fe NM, 6-8 June 1994). Our PIC-MCC simulations and theory [K. Bowers, accompanying paper, and Cooperberg and Birdsall (PSST, Vol. 7, Feb and May 1998)], show similar results. The electron heating profile (J.E) is different from that of a low pressure capacitive discharge. Our scaling laws, at fixed pressure, show peak electron density proportional to the cube of the drive frequency (cap. have as the square), as derived by Godyak (Sov. J. Plasma Phys. Vol. 2, p.78 1976). The electron energy distribution in the bulk is bi-maxwellian. The ion energy distribution at the target (wall) has a peak at the peak average potential, with a narrow ion angular spread about the normal, at low pressures. Results will be shown for a range of pressures from collisionless to collisional. We are supported by DOE DE-FG03-97ER54446 and AFOSR FDF 49620-96-1-0154.

  18. Taylor bubbles at high viscosity ratios: experiments and numerical simulations

    NASA Astrophysics Data System (ADS)

    Hewakandamby, Buddhika; Hasan, Abbas; Azzopardi, Barry; Xie, Zhihua; Pain, Chris; Matar, Omar

    2015-11-01

    The Taylor bubble is a single long bubble which nearly fills the entire cross section of a liquid-filled circular tube, often occurring in gas-liquid slug flows in many industrial applications, particularly oil and gas production. The objective of this study is to investigate the fluid dynamics of three-dimensional Taylor bubble rising in highly viscous silicone oil in a vertical pipe. An adaptive unstructured mesh modelling framework is adopted here which can modify and adapt anisotropic unstructured meshes to better represent the underlying physics of bubble rising and reduce computational effort without sacrificing accuracy. The numerical framework consists of a mixed control volume and finite element formulation, a `volume of fluid'-type method for the interface-capturing based on a compressive control volume advection method, and a force-balanced algorithm for the surface tension implementation. Experimental results for the Taylor bubble shape and rise velocity are presented, together with numerical results for the dynamics of the bubbles. A comparison of the simulation predictions with experimental data available in the literature is also presented to demonstrate the capabilities of our numerical method. EPSRC Programme Grant, MEMPHIS, EP/K0039761/1.

  19. Performance analysis of bullet trajectory estimation: Approach, simulation, and experiments

    SciTech Connect

    Ng, L.C.; Karr, T.J.

    1994-11-08

    This paper describes an approach to estimate a bullet`s trajectory from a time sequence of angles-only observations from a high-speed camera, and analyzes its performance. The technique is based on fitting a ballistic model of a bullet in flight along with unknown source location parameters to a time series of angular observations. The theory is developed to precisely reconstruct, from firing range geometry, the actual bullet trajectory as it appeared on the focal plane array and in real space. A metric for measuring the effective trajectory track error is also presented. Detailed Monte-Carlo simulations assuming different bullet ranges, shot-angles, camera frame rates, and angular noise show that angular track error can be as small as 100 {mu}rad for a 2 mrad/pixel sensor. It is also shown that if actual values of bullet ballistic parameters were available, the bullet s source location variables, and the angles of flight information could also be determined.

  20. Acoustic forcing on swirling flow: experiments and simulation

    NASA Astrophysics Data System (ADS)

    Hubschmid, W.; Denisov, A.; Biagioli, F.

    2014-09-01

    We investigated the effect of sound irradiated from loudspeakers on the flow of preheated air in the combustion chamber of a swirl burner. The temporally periodic pattern of the flow generated by the sound was detected by fast particle image velocimetry (PIV), with a repetition rate that was adapted to the observation of 12 phase angles of the irradiated monochromatic sound. The strong observed movement of the air is related to the movement by the sound itself, as determined by the pressure measurements with microphones. The PIV measurements reveal also a nonlinear interaction between the irradiated sound and the precession of the vortex core. The accuracy of the sound measurements was tested by determining in quiescent air the acoustic velocity by microphones and as well by PIV; good agreement was obtained thereby. Numerical calculations, using large eddy simulation and accounting for the sound forcing by variation in the mass flow at the inlet of the computational domain, approximately reproduce some of the experimental results.

  1. Mechanical behavior of ``living quicksand'': Simulation and Experiment

    NASA Astrophysics Data System (ADS)

    Kadau, Dirk; Herrmann, Hans J.; Andrade, José S.

    2009-06-01

    The nature and danger of quicksand has been disputed since a long time. Despite widespread belief that humans can be swallowed or even sucked in, engineers of soil mechanics have typically asserted that, since the density of sludge is larger than that of water, a person cannot fully submerge. We investigated a specific type of quicksand at the shore of drying lagoons. Cyanobacteria form an impermeable crust, giving the impression of stable ground. After breaking the crust a person rapidly sinks to the bottom of the field. We measured the shear strength of the material before and after perturbation and found a drastic change. The initial structure cannot be restored once it had collapsed, i.e. the material investigated shows a strong memory effect. We simulated a model for this type of quicksand in which we constructed a tenuous granular structure representing the unperturbed soil. The initial structure consists of cohesive disks put together by ballistic deposition and settled by gravity using Contact Dynamics. We study the material behavior by determining the shear strength of the model material and by penetration tests, i.e. pushing in an object, which leads to breaking of cohesive bonds. We investigate how deep the object can be pushed in and how well the intruder is captured by the material after it collapsed above the intruder. During the penetration process we measured the relation between the driving force and the resulting velocity of the intruder.

  2. Simulations for single-dish intensity mapping experiments

    NASA Astrophysics Data System (ADS)

    Bigot-Sazy, M.-A.; Dickinson, C.; Battye, R. A.; Browne, I. W. A.; Ma, Y.-Z.; Maffei, B.; Noviello, F.; Remazeilles, M.; Wilkinson, P. N.

    2015-12-01

    H I intensity mapping is an emerging tool to probe dark energy. Observations of the redshifted H I signal will be contaminated by instrumental noise, atmospheric and Galactic foregrounds. The latter is expected to be four orders of magnitude brighter than the H I emission we wish to detect. We present a simulation of single-dish observations including an instrumental noise model with 1/f and white noise, and sky emission with a diffuse Galactic foreground and H I emission. We consider two foreground cleaning methods: spectral parametric fitting and principal component analysis. For a smooth frequency spectrum of the foreground and instrumental effects, we find that the parametric fitting method provides residuals that are still contaminated by foreground and 1/f noise, but the principal component analysis can remove this contamination down to the thermal noise level. This method is robust for a range of different models of foreground and noise, and so constitutes a promising way to recover the H I signal from the data. However, it induces a leakage of the cosmological signal into the subtracted foreground of around 5 per cent. The efficiency of the component separation methods depends heavily on the smoothness of the frequency spectrum of the foreground and the 1/f noise. We find that as long as the spectral variations over the band are slow compared to the channel width, the foreground cleaning method still works.

  3. Excipient-assisted vinpocetine nanoparticles: experiments and molecular dynamic simulations.

    PubMed

    Li, Cai-Xia; Wang, Hao-Bo; Oppong, Daniel; Wang, Jie-Xin; Chen, Jian-Feng; Le, Yuan

    2014-11-01

    Hydrophilic excipients can be used to increase the solubility and bioavailability of poorly soluble drugs. In this work, the conventional water-soluble pharmaceutical excipients hydroxypropylmethylcellulose (HPMC), polyvinylpyrrolidone (PVP), and lactose (LAC) were used as solid supports to prevent drug nanoparticles from aggregation and enhance drug dissolution. Excipient-assisted vinpocetine (VIN) nanoparticles were prepared by reactive precipitation. The analysis results indicated that HPMC was a suitable excipient to prepare VIN nanoparticles. VIN/HPMC nanoparticles had a mean size of 130 nm within a narrow distribution. The dissolution rate of VIN nanoparticles was significantly faster than those of a physical mixture of VIN/HPMC and raw VIN. VIN/HPMC nanoparticles had a higher dissolution profile than VIN/PVP and VIN/LAC nanoparticles. Besides, molecular dynamics (MD) simulation was applied to investigate the molecular interactions between VIN and excipients. The calculated results revealed that VIN interacted with excipients by Coulomb and Lennard-Jones (LJ) interactions. Few hydrogen bonds were formed between VIN and excipients. The HPMC affording smaller particle size may be a result of the stronger interactions between VIN and HPMC (mainly LJ interaction) and the property of HPMC. These characteristics may greatly influence the adsorption behavior and may be the crucial parameter for the better performance of HPMC. PMID:25244002

  4. Experiment and Simulation of the Lateral Gauge in Glass Targets

    NASA Astrophysics Data System (ADS)

    Church, P. D.; Grief, A.; Tsembelis, K.; Proud, W. G.; Murray, N. H.

    2004-07-01

    The lateral stress in materials has been measured, under shock wave loading, using manganin gauges mounted normal to the direction of shock propagation. Generally the sample has been sectioned along the direction of impact and adhered again with the gauge in this plane. A series of previous papers have reported a two-step structure in the lateral gauge history, the presence or absence of which indicates the presence of failure fronts in a variety of materials, such as ceramics and glasses. In glasses the evidence also includes velocity interferometry (VISAR) traces and high-speed photography where the failure front is also seen. The gauge configurations have been simulated using the QinetiQ Eulerian hydrocode GRIM3D to identify the effect of local material response on the function of the lateral gauge. These initial results have illustrated that tensile fractures occur along the material at the gauge/sample interface, which propagate behind the main shock front. Another feature is that the flyer plate can jet into the region of the lateral cut and therefore impart a separate shock into this region. Curiously these effects seem to have little impact on the predicted lateral stress history.

  5. Reactivity and survivability of glycolaldehyde in simulated meteorite impact experiments.

    PubMed

    McCaffrey, V P; Zellner, N E B; Waun, C M; Bennett, E R; Earl, E K

    2014-02-01

    Sugars of extraterrestrial origin have been observed in the interstellar medium (ISM), in at least one comet spectrum, and in several carbonaceous chondritic meteorites that have been recovered from the surface of the Earth. The origins of these sugars within the meteorites have been debated. To explore the possibility that sugars could be generated during shock events, this paper reports on the results of the first laboratory impact experiments wherein glycolaldehyde, found in the ISM, as well as glycolaldehyde mixed with montmorillonite clay, have been subjected to reverberated shocks from ~5 to >25 GPa. New biologically relevant molecules, including threose, erythrose and ethylene glycol, were identified in the resulting samples. These results show that sugar molecules can not only survive but also become more complex during impact delivery to planetary bodies. PMID:24934564

  6. National Fusion Collaboratory: Grid Computing for Simulations and Experiments

    NASA Astrophysics Data System (ADS)

    Greenwald, Martin

    2004-05-01

    The National Fusion Collaboratory Project is creating a computational grid designed to advance scientific understanding and innovation in magnetic fusion research by facilitating collaborations, enabling more effective integration of experiments, theory and modeling and allowing more efficient use of experimental facilities. The philosophy of FusionGrid is that data, codes, analysis routines, visualization tools, and communication tools should be thought of as network available services, easily used by the fusion scientist. In such an environment, access to services is stressed rather than portability. By building on a foundation of established computer science toolkits, deployment time can be minimized. These services all share the same basic infrastructure that allows for secure authentication and resource authorization which allows stakeholders to control their own resources such as computers, data and experiments. Code developers can control intellectual property, and fair use of shared resources can be demonstrated and controlled. A key goal is to shield scientific users from the implementation details such that transparency and ease-of-use are maximized. The first FusionGrid service deployed was the TRANSP code, a widely used tool for transport analysis. Tools for run preparation, submission, monitoring and management have been developed and shared among a wide user base. This approach saves user sites from the laborious effort of maintaining such a large and complex code while at the same time reducing the burden on the development team by avoiding the need to support a large number of heterogeneous installations. Shared visualization and A/V tools are being developed and deployed to enhance long-distance collaborations. These include desktop versions of the Access Grid, a highly capable multi-point remote conferencing tool and capabilities for sharing displays and analysis tools over local and wide-area networks.

  7. ITER Test Blanket Module Error Field Simulation Experiments

    NASA Astrophysics Data System (ADS)

    Schaffer, M. J.

    2010-11-01

    Recent experiments at DIII-D used an active-coil mock-up to investigate effects of magnetic error fields similar to those expected from two ferromagnetic Test Blanket Modules (TBMs) in one ITER equatorial port. The largest and most prevalent observed effect was plasma toroidal rotation slowing across the entire radial profile, up to 60% in H-mode when the mock-up local ripple at the plasma was ˜4 times the local ripple expected in front of ITER TBMs. Analysis showed the slowing to be consistent with non-resonant braking by the mock-up field. There was no evidence of strong electromagnetic braking by resonant harmonics. These results are consistent with the near absence of resonant helical harmonics in the TBM field. Global particle and energy confinement in H-mode decreased by <20% for the maximum mock-up ripple, but <5% at the local ripple expected in ITER. These confinement reductions may be linked with the large velocity reductions. TBM field effects were small in L-mode but increased with plasma beta. The L-H power threshold was unaffected within error bars. The mock-up field increased plasma sensitivity to mode locking by a known n=1 test field (n = toroidal harmonic number). In H-mode the increased locking sensitivity was from TBM torque slowing plasma rotation. At low beta, locked mode tolerance was fully recovered by re-optimizing the conventional DIII-D ``I-coils'' empirical compensation of n=1 errors in the presence of the TBM mock-up field. Empirical error compensation in H-mode should be addressed in future experiments. Global loss of injected neutral beam fast ions was within error bars, but 1 MeV fusion triton loss may have increased. The many DIII-D mock-up results provide important benchmarks for models needed to predict effects of TBMs in ITER.

  8. Variable rainfall intensity during soil erosion experiments at the laboratory rainfall simulator

    NASA Astrophysics Data System (ADS)

    Laburda, Tomas; Schwarzova, Pavla; Krasa, Josef

    2016-04-01

    Experimental research of soil erosion at the laboratory rainfall simulator at the CTU in Prague continued with 11th soil set Trebesice III in 2014/2015. Standard simulations with constant rainfall intensity were complemented by additional simulations with variable rainfall intensity with two different patterns. The main objective was to determine the feasibility of these experiments and the effect on erosion characteristics compared to those with constant rainfall intensity. This measurement consist of 60 minute simulations (change in intensity in 20. and 40. minute of simulation) with increasing rainfall intensity with pattern of 20-40-60 mm/hr ("inc") and decreasing intensity with pattern of 60-40-20 mm/hr ("dec") which have been compared with experiments with constant rainfall intensity of 40 mm/hr ("c40"). All experiments thus reaching the same total precipitation during entire simulation. This comparison was done on soil sample with dimensions of 4x0,9x0,15 meters and slope adjusted at 4° and 8°. Final evaluation consists of comparison of development and cumulative values of surface runoff and soil loss. In case of steady soil conditions (in this case, the experiments on the slope 4°) results show there is no significant difference in surface runoff in term of cumulative values and development (in the middle period of simulations with rainfall intensity of 40 mm/hr, i.e. 20-40. minute of every experiment) between "c40", "inc" and "dec". On the other hand, results of soil loss from the same experiments differ according to rainfall intensity pattern in both development and cumulative values. While "inc" experiment has slightly lower (up to 10 %) soil loss than "c40", development of soil loss (in the middle period of simulations with 40 mm/hr) of "dec" experiment is almost two times lower compare to "c40". Experiments with longitudinal soil surface of 8° differ in soil moisture that affects results more than variable rainfall intensity pattern. Experimental

  9. CO2/ brine substitution experiments at simulated reservoir conditions

    NASA Astrophysics Data System (ADS)

    Kummerow, Juliane; Spangenberg, Erik

    2015-04-01

    Capillary properties of rocks affect the mobility of fluids in a reservoir. Therefore, the understanding of the capillary pressure behaviour is essential to assess the long-term behaviour of CO2 reservoirs. Beyond this, a calibration of the petrophysical properties on water saturation of reservoir rocks at simulated in situ conditions is crucial for a proper interpretation of field monitoring data. We present a set-up, which allows for the combined measurements of capillary pressure, electric resistivity, and elastic wave velocities under controlled reservoir conditions (pconf = 400 bar, ppore = 180 bar, T = 65 ° C) at different brine-CO2 saturations. The capillary properties of the samples are measured using the micropore membrane technique. The sample is jacketed with a Viton tube (thickness = 4 mm) and placed between two current electrode endcaps, which as well contain pore fluid ports and ultrasonic P and S wave transducers. Between the sample and the lower endcap the hydrophilic semi-permeable micro-pore membrane (pore size = 100 nm) is integrated. It is embedded into filter papers to establish a good capillary contact and to protect the highly sensitive membrane against mechanical damage under load. Two high-precision syringe pumps are used to displace a quantified volume of brine by CO2 and determine the corresponding sample saturation. The fluid displacement induces a pressure gradient along the sample, which corresponds to the capillary pressure at a particular sample saturation. It is measured with a differential pressure sensor in the range between 0 - 0.2 MPa. Drainage and imbibition cycles are performed to provide information on the efficiency of capillary trapping and to get a calibration of the petrophysical parameters of the sample.

  10. Ion dynamics in a supersonic jet: Experiments and simulations.

    PubMed

    Caldirola, S; Roman, H E; Riccardi, C

    2016-03-01

    The authors suggest a model to simulate the dynamics of ions in a supersonic plasma jet. The model relies on experimental argon ion, Ar(+), energy distribution functions measured by a quadrupole mass spectrometer at different positions along the central axis of a supersonic argon plasma jet. The latter is generated by the pressure difference between two vacuum chambers connected through a converging nozzle: a high-pressure chamber (P ≃ 3.20 Pa), where an inductively coupled argon plasma discharge is maintained, and a lower-pressure one (P ≃ 0.11 Pa), where the plasma jet expands. The model is based on the integration of the equations of motion of a single Ar(+), moving along the supersonic jet in a reference system in which neutral species are at rest. Ar(+)-Ar induced dipole interactions are treated using a 12-4 Lennard-Jones potential. The resulting collisions are considered to be purely elastic, and in addition to them, we allow for charge transfer processes. The energy and position of 1000 Ar(+) were calculated, using an integration time step of 10 ps for ion trajectories ranging from 5 mm to 20 mm from the nozzle, well inside the spatial extension of the supersonic jet. The numerically obtained ion energy distribution functions agree remarkably well with the experimental measurements. From our calculations we can draw conclusions about the energy loss and the mean free paths along the jet. In particular, we can distinguish between processes with and without charge transfer, allowing us to determine the effect of charge exchange phenomena in which the ion changes its nature. The calculated mean free paths were used to evaluate the effective cross sections for momentum transfer and charge transfer collisions, valid for ion energies in the range (0.5-10) eV, in very good agreement with those reported in the literature. PMID:27078470

  11. Carbocyanines in an RNA environment: experiment meets simulation (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Boerner, Richard; Steffen, Fabio; Sigel, Roland K. O.

    2016-02-01

    The popularity of carbocyanine dyes in single molecule spectroscopy of nucleic acids is unbroken [1]. Studying the dynamics of large RNA constructs and the binding kinetics such as the exon/intron binding side interaction of the group II intron in S. Cerevisiae [2,3] have motivated a thorough photophysical characterization of the FRET pair Cy3/Cy5 in context of nucleic acids and RNA in particular. We show that Mg2+ as a mediator of RNA-dye interactions enhances the cyanine fluorescence lifetime. The increasing window for depolarization as monitored by time-resolved anisotropy further revealed a dynamic equilibrium between free tumbling and stacking on the RNA backbone, with the stacked conformation preventing photoisomerization [4]. Tracking fluorophore mobility covalently bound to the RNA on an atomistic level by means of molecular dynamics [5] allow to disentangle different types of dye-dye and dye-RNA interactions. Our hybrid approach combining time-correlated single photon counting and computer simulations will benefit the interpretation of absolute distance measurement by smFRET. [1] M.Levitus and S.Ranjit, Q. Rev. Biophys 2011, 44, 123-151. [2] D.Kowerko, S.L.B.König, M.Skilandat, D.Kruschel, M.C.A.S.Hadzic, L.Cardo, R.K.O.Sigel, PNAS 2015, 112, 3403-3408. [3] M. Khier, D. Kowerko, F. Steffen, R. Börner and R.K.O.Sigel, in preparation. [4] F.Steffen, R.K.O. Sigel, R.Börner, in preparation. [5] R.Best, H. Hofmann, D. Nettels, B. Schuler, Biophys J 2015, 11,2721-2731.

  12. Ion dynamics in a supersonic jet: Experiments and simulations

    NASA Astrophysics Data System (ADS)

    Caldirola, S.; Roman, H. E.; Riccardi, C.

    2016-03-01

    The authors suggest a model to simulate the dynamics of ions in a supersonic plasma jet. The model relies on experimental argon ion, Ar+, energy distribution functions measured by a quadrupole mass spectrometer at different positions along the central axis of a supersonic argon plasma jet. The latter is generated by the pressure difference between two vacuum chambers connected through a converging nozzle: a high-pressure chamber (P ≃3.20 Pa), where an inductively coupled argon plasma discharge is maintained, and a lower-pressure one (P ≃0.11 Pa), where the plasma jet expands. The model is based on the integration of the equations of motion of a single Ar+, moving along the supersonic jet in a reference system in which neutral species are at rest. Ar+-Ar induced dipole interactions are treated using a 12-4 Lennard-Jones potential. The resulting collisions are considered to be purely elastic, and in addition to them, we allow for charge transfer processes. The energy and position of 1000 Ar+ were calculated, using an integration time step of 10 ps for ion trajectories ranging from 5 mm to 20 mm from the nozzle, well inside the spatial extension of the supersonic jet. The numerically obtained ion energy distribution functions agree remarkably well with the experimental measurements. From our calculations we can draw conclusions about the energy loss and the mean free paths along the jet. In particular, we can distinguish between processes with and without charge transfer, allowing us to determine the effect of charge exchange phenomena in which the ion changes its nature. The calculated mean free paths were used to evaluate the effective cross sections for momentum transfer and charge transfer collisions, valid for ion energies in the range (0.5-10) eV, in very good agreement with those reported in the literature.

  13. The Run-by-Run Monte Carlo simulation for the ANTARES experiment

    NASA Astrophysics Data System (ADS)

    Fusco, L. A.; Margiotta, A.

    2016-04-01

    The ANTARES neutrino telescope is the largest and longest-operated underwater neutrino telescope. Data acquisition conditions in a marine environment are not stable in time: biological and physical phenomena follow a seasonal evolution producing a periodical change of the rates registered at the neutrino telescope. Variations in the sea current velocity also affect the measured baseline value and the burst fraction on short time scales. Monte Carlo simulations of the detector response to charged particles in the proximity of the telescope should reproduce the conditions of the medium and of the acquisition setup as much as possible. An efficient way to account for their variability is to extract related information directly from the data runs. A Run-by-Run simulation procedure has been developed to follow the time evolution of data acquisition in ANTARES.

  14. Analysis procedures and subjective flight results of a simulator validation and cue fidelity experiment

    NASA Technical Reports Server (NTRS)

    Carr, Peter C.; Mckissick, Burnell T.

    1988-01-01

    A joint experiment to investigate simulator validation and cue fidelity was conducted by the Dryden Flight Research Facility of NASA Ames Research Center (Ames-Dryden) and NASA Langley Research Center. The primary objective was to validate the use of a closed-loop pilot-vehicle mathematical model as an analytical tool for optimizing the tradeoff between simulator fidelity requirements and simulator cost. The validation process includes comparing model predictions with simulation and flight test results to evaluate various hypotheses for differences in motion and visual cues and information transfer. A group of five pilots flew air-to-air tracking maneuvers in the Langley differential maneuvering simulator and visual motion simulator and in an F-14 aircraft at Ames-Dryden. The simulators used motion and visual cueing devices including a g-seat, a helmet loader, wide field-of-view horizon, and a motion base platform.

  15. Professors' and students' perceptions and experiences of computational simulations as learning tools

    NASA Astrophysics Data System (ADS)

    Magana de Leon, Alejandra De Jesus

    Computational simulations are becoming a critical component of scientific and engineering research, and now are becoming an important component for learning. This dissertation provides findings from a multifaceted research study exploring the ways computational simulations have been perceived and experienced as learning tools by instructors and students. Three studies were designed with an increasing focus on the aspects of learning and instructing with computational simulation tools. Study One used a student survey with undergraduate and graduate students whose instructors enhanced their teaching using online computational tools. Results of this survey were used to identify students' perceptions and experiences with these simulations as learning tools. The results provided both an evaluation of the instructional design and an indicator of which instructors were selected in Study Two. Study Two used a phenomenographic research design resulting in a two dimensional outcome space with six qualitatively different ways instructors perceived their learning outcomes associated with using simulation tools as part of students' learning experiences. Results from this work provide a framework for identifying major learning objectives to promote learning with computational simulation tools. Study Three used a grounded theory methodology to expand on instructors' learning objectives to include their perceptions of formative assessment and pedagogy. These perceptions were compared and contrasted with students' perceptions associated with learning with computational tools. The study is organized around three phases and analyzed as a collection of case studies focused on the instructors and their students' perceptions and experiences of computational simulations as learning tools. This third study resulted in a model for using computational simulations as learning tools. This model indicates the potential of integrating the computational simulation tools into formal learning

  16. Simulating the multistage environment for single-stage compressor experiments

    SciTech Connect

    Place, J.M.M.; Howard, M.A.; Cumpsty, N.A.

    1996-10-01

    The performance of a single-stage low-speed compressor has been measured both before and after the introduction of certain features of the multistage flow environment. The aim is to make the single-stage rig more appropriate for developing design rules for multistage compressors. End-wall blockage was generated by teeth on the hub and casing upstream of the rotor. A grid fitted upstream produced free-stream turbulence at rotor inlet typical of multistage machines and raised stage efficiency by 1.8 percent at the design point. The potential field that would be generated by blade rows downstream of an embedded stage was replicated by introducing a pressure loss screen at stage exit. This reduced the stator hub corner separation and increased the rotor pressure rise at flow rates below design, changing the shape of the pressure-rise characteristic markedly. These results highlight the importance of features of the flow environment that are often omitted from single-stage experiments and offer improved understanding of stage aerodynamics.

  17. Dynamics of molecular clouds: observations, simulations, and NIF experiments

    NASA Astrophysics Data System (ADS)

    Kane, Jave O.; Martinez, David A.; Pound, Marc W.; Heeter, Robert F.; Casner, Alexis; Mancini, Roberto C.

    2015-02-01

    For over fifteen years astronomers at the University of Maryland and theorists and experimentalists at LLNL have investigated the origin and dynamics of the famous Pillars of the Eagle Nebula, and similar parsec-scale structures at the boundaries of HII regions in molecular hydrogen clouds. Eagle Nebula was selected as one of the National Ignition Facility (NIF) Science programs, and has been awarded four NIF shots to study the cometary model of pillar formation. These experiments require a long-duration drive, 30 ns or longer, to drive deeply nonlinear ablative hydrodynamics. The NIF shots will feature a new long-duration x-ray source prototyped at the Omega EP laser, in which multiple hohlraums are driven with UV light in series for 10 ns each and reradiate the energy as an extended x-ray pulse. The new source will be used to illuminate a science package with directional radiation mimicking a cluster of stars. The scaled Omega EP shots tested whether a multi-hohlraum concept is viable — whether earlier time hohlraums would degrade later time hohlraums by preheat or by ejecting ablated plumes that would deflect the later beams. The Omega EP shots illuminated three 2.8 mm long by 1.4 mm diameter Cu hohlraums for 10 ns each with 4.3 kJ per hohlraum. At NIF each hohlraum will be 4 mm long by 3 mm in diameter and will be driven with 80 kJ per hohlraum.

  18. Low energy and low fluence helium implantations in tungsten: Molecular dynamics simulations and experiments

    NASA Astrophysics Data System (ADS)

    Pentecoste, L.; Brault, P.; Thomann, A.-L.; Desgardin, P.; Lecas, T.; Belhabib, T.; Barthe, M.-F.; Sauvage, T.

    2016-03-01

    300 eV Helium implantation process into tungsten at 300 K has been studied with molecular dynamic simulations (MD). Predicted retention doses were compared to that obtained from experiments performed in equivalent conditions. A saturation phenomenon of the helium retention was evidenced for a number of impinging He atoms and a retention dose similar in both, experiments and simulations. From MD simulations it is learnt that observed Helium diffusion, formation and coalescence of clusters are the phenomena leading to the flaking of the substrate. These processes could explain the saturation of the Helium retention observed experimentally at low energies.

  19. Serious games experiment toward agent-based simulation

    USGS Publications Warehouse

    Wein, Anne; Labiosa, William

    2013-01-01

    We evaluate the potential for serious games to be used as a scientifically based decision-support product that supports the United States Geological Survey’s (USGS) mission--to provide integrated, unbiased scientific information that can make a substantial contribution to societal well-being for a wide variety of complex environmental challenges. Serious or pedagogical games are an engaging way to educate decisionmakers and stakeholders about environmental challenges that are usefully informed by natural and social scientific information and knowledge and can be designed to promote interactive learning and exploration in the face of large uncertainties, divergent values, and complex situations. We developed two serious games that use challenging environmental-planning issues to demonstrate and investigate the potential contributions of serious games to inform regional-planning decisions. Delta Skelta is a game emulating long-term integrated environmental planning in the Sacramento-San Joaquin Delta, California, that incorporates natural hazards (flooding and earthquakes) and consequences for California water supplies amidst conflicting water interests. Age of Ecology is a game that simulates interactions between economic and ecologic processes, as well as natural hazards while implementing agent-based modeling. The content of these games spans the USGS science mission areas related to water, ecosystems, natural hazards, land use, and climate change. We describe the games, reflect on design and informational aspects, and comment on their potential usefulness. During the process of developing these games, we identified various design trade-offs involving factual information, strategic thinking, game-winning criteria, elements of fun, number and type of players, time horizon, and uncertainty. We evaluate the two games in terms of accomplishments and limitations. Overall, we demonstrated the potential for these games to usefully represent scientific information

  20. NASA/ESACV-990 spacelab simulation. Appendix B: Experiment development and performance

    NASA Technical Reports Server (NTRS)

    Reller, J. O., Jr.; Neel, C. B.; Haughney, L. C.

    1976-01-01

    Eight experiments flown on the CV-990 airborne laboratory during the NASA/ESA joint Spacelab simulation mission are described in terms of their physical arrangement in the aircraft, their scientific objectives, developmental considerations dictated by mission requirements, checkout, integration into the aircraft, and the inflight operation and performance of the experiments.

  1. Get Real: Effects of Repeated Simulation and Emotion on the Perceived Plausibility of Future Experiences

    ERIC Educational Resources Information Center

    Szpunar, Karl K.; Schacter, Daniel L.

    2013-01-01

    People frequently imagine specific interpersonal experiences that might occur in their futures. The present study used a novel experimental paradigm to examine the influence of repeated simulation of future interpersonal experiences on subjective assessments of plausibility for positive, negative, and neutral events. The results demonstrate that…

  2. Simulated and Virtual Science Laboratory Experiments: Improving Critical Thinking and Higher-Order Learning Skills

    ERIC Educational Resources Information Center

    Simon, Nicole A.

    2013-01-01

    Virtual laboratory experiments using interactive computer simulations are not being employed as viable alternatives to laboratory science curriculum at extensive enough rates within higher education. Rote traditional lab experiments are currently the norm and are not addressing inquiry, Critical Thinking, and cognition throughout the laboratory…

  3. An Educational Software for Simulating the Sample Size of Molecular Marker Experiments

    ERIC Educational Resources Information Center

    Helms, T. C.; Doetkott, C.

    2007-01-01

    We developed educational software to show graduate students how to plan molecular marker experiments. These computer simulations give the students feedback on the precision of their experiments. The objective of the software was to show students using a hands-on approach how: (1) environmental variation influences the range of the estimates of the…

  4. Atmospheric media effects on ARIES baseline determination

    NASA Technical Reports Server (NTRS)

    Wu, S. C.

    1981-01-01

    Different types of media effects on ARIES baseline determination are compared. The effectiveness of simple ionospheric calibration models are studied. To perform the covariance analysis, an ARIES observation sequence needs to be assumed. For the current purposes, the observation sequence is selected to be that of experiment 80D over the JPL/Goldstone baseline (approximately 180 km). This experiment consisted of 96 observations over a period of approximately 25 hours on March 25 to 26, 1980. It is found through covariance analyses that the component most sensitive to media depends heavily upon the correlation, between the two stations, of the media effects. It is also found that relying on the cancellation of ionospheric delays between the two ray paths of VLBI observations at S band results in a large error in baseline length determination. High degree removal of ionospheric effects is possible with a crude model, providing correct diurnal peak and minimum ionospheric levels are input.

  5. Simulated rainfall experiments on water repellent post mine sites

    NASA Astrophysics Data System (ADS)

    Kunth, Franziska; Schmidt, Jürgen

    2013-04-01

    Reclaimed lignite mine areas are heavily endangered by erosion by water. This leads to heavy soil losses, especially on hydrophobic and non-vegetated soil surfaces. Beyond that, erosion-induced discharge of detached dump particles in abandoned open pits leads to acidification of surface waters. Therefore land management in former mining regions requires long-term and safe structuring of recultivation areas. The objective of this ongoing study is the development of a methodology to determine erosion risks on slopes in recultivation areas with the help of the event-based physical erosion model EROSION 2D/3D (Schmidt, 1991, 1992; v. Werner, 1995). The widely used model is able to predict runoff as well as detachment, transport and deposition of sediments. Lignite dump materials show strong water repellency due to hydrophobic substances that coat soil particles. As affecting infiltration processes the effect of water repellency had to be implemented into EROSION 2D/3D. To obtain necessary input data for erosion modelling (hydraulic roughness, infiltration rates, calibration factors, etc.) a number of rainfall experiments on non-vegetated as well as recultivated reclaimed mine sites in the Lusatia lignite mining region (southeast of Berlin, Germany) were conducted. Very low infiltration rates were measured on non-vegetated water repellent sites. These processes could be described by EROSION 2D infiltration modelling. Changes of surface runoff and particle detachment and dynamic effects on infiltration are considered with the experimentally determined parameters "skin-factor", "resistance to erosion" and "hydraulic roughness". Current analysis show that a newly developed water repellency-factor helps to depict infiltration and erosion processes on water repellent dump soils.

  6. Diffusion of volatile compounds in fibre networks: experiments and modelling by random walk simulation.

    PubMed

    Aurela, B; Ketoja, J A

    2002-01-01

    Predictive migration models for polymers are already so well established that the European Commission intends to allow the use of the models as one quality assurance tool in product safety assessment of plastic materials and articles for food contact. The inhomogeneity of fibre-based materials makes modelling difficult--thus, little research has been done in this area. The authors compare experiments on the diffusion of certain volatile compounds through laboratory kraft pulp sheets with computer simulations in which the fibre network structure is modelled explicitly. The major advantage of the present random walk simulation is that it gives an estimate of the effective diffusion constant for the fibre network. For most compounds, the agreement between the experiments and simulations is good. The experiments and simulations indicate that gas diffusion rate is very sensitive to sheet porosity. PMID:11962715

  7. In-flight thermal experiments for LISA Pathfinder: Simulating temperature noise at the Inertial Sensors

    NASA Astrophysics Data System (ADS)

    Gibert, F.; Nofrarias, M.; Armano, M.; Audley, H.; Auger, G.; Baird, J.; Binetruy, P.; Born, M.; Bortoluzzi, D.; Brandt, N.; Bursi, A.; Caleno, M.; Cavalleri, A.; Cesarini, A.; Cruise, M.; Danzmann, K.; Diepholz, I.; Dolesi, R.; Dunbar, N.; Ferraioli, L.; Ferroni, V.; Fitzsimons, E.; Freschi, M.; Gallegos, J.; García Marirrodriga, C.; Gerndt, R.; Gesa, Ll; Giardini, D.; Giusteri, R.; Grimani, C.; Harrison, I.; Heinzel, G.; Hewitson, M.; Hollington, D.; Hueller, M.; Huesler, J.; Inchauspé, H.; Jennrich, O.; Jetzer, P.; Johlander, B.; Karnesis, N.; Kaune, B.; Korsakova, N.; Killow, C.; Lloro, I.; Maarschalkerweerd, R.; Madden, S.; Maghami, P.; Mance, D.; Martín, V.; Martin-Porqueras, F.; Mateos, I.; McNamara, P.; Mendes, J.; Mendes, L.; Moroni, A.; Paczkowski, S.; Perreur-Lloyd, M.; Petiteau, A.; Pivato, P.; Plagnol, E.; Prat, P.; Ragnit, U.; Ramos-Castro, J.; Reiche, J.; Romera Perez, J. A.; Robertson, D.; Rozemeijer, H.; Russano, G.; Sarra, P.; Schleicher, A.; Slutsky, J.; Sopuerta, C. F.; Sumner, T.; Texier, D.; Thorpe, J.; Trenkel, C.; Tu, H. B.; Vetrugno, D.; Vitale, S.; Wanner, G.; Ward, H.; Waschke, S.; Wass, P.; Wealthy, D.; Wen, S.; Weber, W.; Wittchen, A.; Zanoni, C.; Ziegler, T.; Zweifel, P.

    2015-05-01

    Thermal Diagnostics experiments to be carried out on board LISA Pathfinder (LPF) will yield a detailed characterisation of how temperature fluctuations affect the LTP (LISA Technology Package) instrument performance, a crucial information for future space based gravitational wave detectors as the proposed eLISA. Amongst them, the study of temperature gradient fluctuations around the test masses of the Inertial Sensors will provide as well information regarding the contribution of the Brownian noise, which is expected to limit the LTP sensitivity at frequencies close to 1 mHz during some LTP experiments. In this paper we report on how these kind of Thermal Diagnostics experiments were simulated in the last LPF Simulation Campaign (November, 2013) involving all the LPF Data Analysis team and using an end-to-end simulator of the whole spacecraft. Such simulation campaign was conducted under the framework of the preparation for LPF operations.

  8. In-flight thermal experiments for LISA Pathfinder: Simulating temperature noise at the Inertial Sensors

    NASA Astrophysics Data System (ADS)

    Armano, M.; Audley, H.; Auger, G.; Baird, J.; Binetruy, P.; Born, M.; Bortoluzzi, D.; Brandt, N.; Bursi, A.; Caleno, M.; Cavalleri, A.; Cesarini, A.; Cruise, M.; Danzmann, K.; Diepholz, I.; Dolesi, R.; Dunbar, N.; Ferraioli, L.; Ferroni, V.; Fitzsimons, E.; Freschi, M.; Gallegos, J.; García Marirrodriga, C.; Gerndt, R.; Gesa, Ll; Gibert, F.; Giardini, D.; Giusteri, R.; Grimani, C.; Harrison, I.; Heinzel, G.; Hewitson, M.; Hollington, D.; Hueller, M.; Huesler, J.; Inchauspé, H.; Jennrich, O.; Jetzer, P.; Johlander, B.; Karnesis, N.; Kaune, B.; Korsakova, N.; Killow, C.; Lloro, I.; Maarschalkerweerd, R.; Madden, S.; Maghami, P.; Mance, D.; Martín, V.; Martin-Porqueras, F.; Mateos, I.; McNamara, P.; Mendes, J.; Mendes, L.; Moroni, A.; Nofrarias, M.; Paczkowski, S.; Perreur-Lloyd, M.; Petiteau, A.; Pivato, P.; Plagnol, E.; Prat, P.; Ragnit, U.; Ramos-Castro, J.; Reiche, J.; Romera Perez, J. A.; Robertson, D.; Rozemeijer, H.; Russano, G.; Sarra, P.; Schleicher, A.; Slutsky, J.; Sopuerta, C. F.; Sumner, T.; Texier, D.; Thorpe, J.; Trenkel, C.; Tu, H. B.; Vetrugno, D.; Vitale, S.; Wanner, G.; Ward, H.; Waschke, S.; Wass, P.; Wealthy, D.; Wen, S.; Weber, W.; Wittchen, A.; Zanoni, C.; Ziegler, T.; Zweifel, P.

    2015-04-01

    Thermal Diagnostics experiments to be carried out on board LISA Pathfinder (LPF) will yield a detailed characterisation of how temperature fluctuations affect the LTP (LISA Technology Package) instrument performance, a crucial information for future space based gravitational wave detectors as the proposed eLISA. Amongst them, the study of temperature gradient fluctuations around the test masses of the Inertial Sensors will provide as well information regarding the contribution of the Brownian noise, which is expected to limit the LTP sensitivity at frequencies close to 1 mHz during some LTP experiments. In this paper we report on how these kind of Thermal Diagnostics experiments were simulated in the last LPF Simulation Campaign (November, 2013) involving all the LPF Data Analysis team and using an end-to-end simulator of the whole spacecraft. Such simulation campaign was conducted under the framework of the preparation for LPF operations.

  9. Use of Simulation Learning Experiences in Physical Therapy Entry-to-Practice Curricula: A Systematic Review

    PubMed Central

    Carnahan, Heather; Herold, Jodi

    2015-01-01

    ABSTRACT Purpose: To review the literature on simulation-based learning experiences and to examine their potential to have a positive impact on physiotherapy (PT) learners' knowledge, skills, and attitudes in entry-to-practice curricula. Method: A systematic literature search was conducted in the MEDLINE, CINAHL, Embase Classic+Embase, Scopus, and Web of Science databases, using keywords such as physical therapy, simulation, education, and students. Results: A total of 820 abstracts were screened, and 23 articles were included in the systematic review. While there were few randomized controlled trials with validated outcome measures, some discoveries about simulation can positively affect the design of the PT entry-to-practice curricula. Using simulators to provide specific output feedback can help students learn specific skills. Computer simulations can also augment students' learning experience. Human simulation experiences in managing the acute patient in the ICU are well received by students, positively influence their confidence, and decrease their anxiety. There is evidence that simulated learning environments can replace a portion of a full-time 4-week clinical rotation without impairing learning. Conclusions: Simulation-based learning activities are being effectively incorporated into PT curricula. More rigorously designed experimental studies that include a cost–benefit analysis are necessary to help curriculum developers make informed choices in curriculum design. PMID:25931672

  10. Ultrafast Dynamics of Carboxy-Hemoglobin: Two-Dimensional Infrared Spectroscopy Experiments and Simulations.

    PubMed

    Falvo, Cyril; Daniault, Louis; Vieille, Thibault; Kemlin, Vincent; Lambry, Jean-Christophe; Meier, Christoph; Vos, Marten H; Bonvalet, Adeline; Joffre, Manuel

    2015-06-18

    This Letter presents a comparison between experimental and simulated 2D mid-infrared spectra of carboxy-hemoglobin in the spectral region of the carbon monoxide stretching mode. The simulations rely on a fluctuating potential energy surface that includes both the effect of heme and the protein surroundings computed from molecular dynamics simulations. A very good agreement between theory and experiment is obtained with no adjustable parameters. The simulations show that the effect of the distal histidine through the hydrogen bond is strong and is directly responsible for the slow decay of the frequency-frequency correlation function on a 10 ps time scale. This study confirms that fluctuations in carboxy-hemoglobin are more inhomogeneous than those in the more frequently studied carboxy-myoglobin. The comparison between simulations and experiments brings valuable information on the complex relation between protein structure and spectral diffusion. PMID:26266594

  11. Overlay metrology for dark hard mask process: simulation and experiment study

    NASA Astrophysics Data System (ADS)

    Shin, Jangho; Chalykh, Roman; Kang, Hyunjae; Kim, SeongSue; Lee, SukJoo; Cho, Han-Ku

    2007-03-01

    Simulation and experimental study results are reported to solve align/overlay problem in dark hard mask process in lithography. For simulation part, an in-house simulator, which is based on rigorous coupled wave analysis and Fourier optics method of high NA imaging, is used. According to the simulation and experiment study, image quality of alignment and overlay marks can be optimized by choosing hard mask and sub-film thickness carefully for a given process condition. In addition, it is important to keep the specification of film thickness uniformity within a certain limit. Simulation results are confirmed by experiment using the state of art memory process in Samsung semiconductor R&D facility.

  12. Characteristics of air puffs produced in English "pa": experiments and simulations.

    PubMed

    Derrick, Donald; Anderson, Peter; Gick, Bryan; Green, Sheldon

    2009-04-01

    Three dimensional large eddy simulations, microphone "pop" measurements, and high-speed videos of the airflow and lip opening associated with the syllable "pa" are presented. In the simulations, the mouth is represented by a narrow static ellipse with a back pressure dropping to 110th of its initial value within 60 ms of the release. The simulations show a jet penetration rate that falls within range of the pressure front of microphone pop. The simulations and high-speed video experiments were within 20% agreement after 40 ms, with the video experiments showing a slower penetration rate than the simulations during the first 40 ms. Kinematic measurements indicate that rapid changes in lip geometry during the first 40 ms underlie this discrepancy. These findings will be useful for microphone manufacturers, sound engineers, and researchers in speech aerodynamics modeling and articulatory speech synthesis. PMID:19354402

  13. A simulation study of the flight dynamics of elastic aircraft. Volume 1: Experiment, results and analysis

    NASA Technical Reports Server (NTRS)

    Waszak, Martin R.; Davidson, John B.; Schmidt, David K.

    1987-01-01

    The simulation experiment described addresses the effects of structural flexibility on the dynamic characteristics of a generic family of aircraft. The simulation was performed using the NASA Langley VMS simulation facility. The vehicle models were obtained as part of this research. The simulation results include complete response data and subjective pilot ratings and comments and so allow a variety of analyses. The subjective ratings and analysis of the time histories indicate that increased flexibility can lead to increased tracking errors, degraded handling qualities, and changes in the frequency content of the pilot inputs. These results, furthermore, are significantly affected by the visual cues available to the pilot.

  14. Simulation study of Hohlraum experiments on SGIII-prototype laser facility

    SciTech Connect

    Huo Wenyi; Ren Guoli; Lan Ke; Li Xin; Wu Changshu; Li Yongsheng; Zhai Chuanlei; Qiao Xiumei; Meng Xujun; Lai Dongxian; Zheng Wudi; Gu Peijun; Pei Wenbing; Li Sanwei; Yi Rongqing; Song Tianming; Jiang Xiaohua; Yang Dong; Jiang Shaoen; Ding Yongkun

    2010-12-15

    The Hohlraum physics experiments performed on the SGIII-prototype laser facility are simulated by using our two-dimensional radiation hydrodynamic code LARED-H, and the influence of laser intensity on the two-dimensional Hohlraum simulations is studied. Both the temporal radiation temperature and the x-ray spectrum from the simulations agree well with the observations, except that the simulated M-band fraction (greater than 2 keV) is obviously smaller than the observation. According to our study, the coupling efficiency from laser to x-ray is around 70% for SGIII-prototype laser facility Hohlraums.

  15. Event-by-event simulation of a quantum delayed-choice experiment

    NASA Astrophysics Data System (ADS)

    Donker, Hylke C.; De Raedt, Hans; Michielsen, Kristel

    2014-12-01

    The quantum delayed-choice experiment of Tang et al. (2012) is simulated on the level of individual events without making reference to concepts of quantum theory or without solving a wave equation. The simulation results are in excellent agreement with the quantum theoretical predictions of this experiment. The implication of the work presented in the present paper is that the experiment of Tang et al. can be explained in terms of cause-and-effect processes in an event-by-event manner.

  16. Impact fracture experiments simulating interstellar grain-grain collisions

    NASA Technical Reports Server (NTRS)

    Freund, Friedemann; Chang, Sherwood; Dickinson, J. Thomas

    1990-01-01

    Oxide and silicate grains condensing during the early phases of the formation of the solar system or in the outflow of stars are exposed to high partial pressures of the low-z elements H, C, N and O and their simple gaseous compounds. Though refractory minerals are nominally anhydrous and non-carbonate, if they crystallize in the presence of H2O, N2 and CO or CO2 gases, they dissolve traces of the gaseous components. The question arises: How does the presence of dissolved gases or gas components manifest itself when grain-grain collisions occur. What are the gases emitted when grains are shattered during a collision event. Researchers report on fracture experiments in ultrahigh vacuum (UHV, approximately less than 10 to the -8th power mbar) designed to measure (by means of a quadrupole mass spectrometer, QMS, with microns to ms time resolution) the emission of gases and vapors during and after impact (up to 1.5 sec). Two terrestrial materials were chosen which represent structural and compositional extremes: olivine (San Carlos, AZ), a densely packed Mg-Fe(2+) silicate from the upper mantle, available as 6 to 12 mm single crystals, and obsidian (Oregon), a structurally open, alkaline-SiO2-rich volcanic glass. In the olivine crystals OH- groups have been identified spectroscopically, as well as H2 molecules. Obsidian is a water-rich glass containing OH- besides H2O molecules. Olivine from the mantle often contains CO2, either as CO2-rich fluid in fluid inclusions or structurally dissolved or both. By analogy to synthetic glasses CO2 in the obsidian may be present in form of CO2 molecules in voids of molecular dimensions, or as carbonate anions, CO3(2-). No organic molecules have been detected spectroscopically in either material. Results indicate that refractory oxide/silicates which contain dissolved traces of the H2O and CO/CO2 components but no spectroscopically detectable traces of organics may release complex H-C-O (possibly H-C-N-O) molecules upon fracture

  17. Impact fracture experiments simulating interstellar grain-grain collisions

    NASA Astrophysics Data System (ADS)

    Freund, Friedemann; Chang, Sherwood; Dickinson, J. Thomas

    1990-04-01

    Oxide and silicate grains condensing during the early phases of the formation of the solar system or in the outflow of stars are exposed to high partial pressures of the low-z elements H, C, N and O and their simple gaseous compounds. Though refractory minerals are nominally anhydrous and non-carbonate, if they crystallize in the presence of H2O, N2 and CO or CO2 gases, they dissolve traces of the gaseous components. The question arises: How does the presence of dissolved gases or gas components manifest itself when grain-grain collisions occur. What are the gases emitted when grains are shattered during a collision event. Researchers report on fracture experiments in ultrahigh vacuum (UHV, approximately less than 10 to the -8th power mbar) designed to measure (by means of a quadrupole mass spectrometer, QMS, with microns to ms time resolution) the emission of gases and vapors during and after impact (up to 1.5 sec). Two terrestrial materials were chosen which represent structural and compositional extremes: olivine (San Carlos, AZ), a densely packed Mg-Fe(2+) silicate from the upper mantle, available as 6 to 12 mm single crystals, and obsidian (Oregon), a structurally open, alkaline-SiO2-rich volcanic glass. In the olivine crystals OH- groups have been identified spectroscopically, as well as H2 molecules. Obsidian is a water-rich glass containing OH- besides H2O molecules. Olivine from the mantle often contains CO2, either as CO2-rich fluid in fluid inclusions or structurally dissolved or both. By analogy to synthetic glasses CO2 in the obsidian may be present in form of CO2 molecules in voids of molecular dimensions, or as carbonate anions, CO3(2-). No organic molecules have been detected spectroscopically in either material. Results indicate that refractory oxide/silicates which contain dissolved traces of the H2O and CO/CO2 components but no spectroscopically detectable traces of organics may release complex H-C-O (possibly H-C-N-O) molecules upon fracture

  18. Event-by-event simulation of experiments to create entanglement and violate Bell inequalities

    NASA Astrophysics Data System (ADS)

    Michielsen, K.; De Raedt, H.

    2013-10-01

    We discuss a discrete-event, particle-based simulation approach which reproduces the statistical distributions of Maxwell's theory and quantum theory by generating detection events one-by-one. This event-based approach gives a unified causeand- effect description of quantum optics experiments such as single-photon Mach-Zehnder interferometer, Wheeler's delayed choice, quantum eraser, double-slit, Einstein-Podolsky-Rosen-Bohm and Hanbury Brown-Twiss experiments, and various neutron interferometry experiments. We illustrate the approach by application to single-photon Einstein-Podolsky- Rosen-Bohm experiments and single-neutron interferometry experiments that violate a Bell inequality.

  19. NPTool: a simulation and analysis framework for low-energy nuclear physics experiments

    NASA Astrophysics Data System (ADS)

    Matta, A.; Morfouace, P.; de Séréville, N.; Flavigny, F.; Labiche, M.; Shearman, R.

    2016-08-01

    The Nuclear Physics Tool (NPTool) is an open source data analysis and Monte Carlo simulation framework that has been developed for low-energy nuclear physics experiments with an emphasis on radioactive beam experiments. The NPTool offers a unified framework for designing, preparing and analyzing complex experiments employing multiple detectors, each of which may comprise some hundreds of channels. The framework has been successfully used for the analysis and simulation of experiments at facilities including GANIL, RIKEN, ALTO and TRIUMF, using both stable and radioactive beams. This paper details the NPTool philosophy together with an overview of the workflow. The framework has been benchmarked through the comparison of simulated and experimental data for a variety of detectors used in charged particle and gamma-ray spectroscopy.

  20. A baseline lunar mine

    NASA Technical Reports Server (NTRS)

    Gertsch, Richard E.

    1992-01-01

    A models lunar mining method is proposed that illustrates the problems to be expected in lunar mining and how they might be solved. While the method is quite feasible, it is, more importantly, a useful baseline system against which to test other, possible better, methods. Our study group proposed the slusher to stimulate discussion of how a lunar mining operation might be successfully accomplished. Critics of the slusher system were invited to propose better methods. The group noted that while nonterrestrial mining has been a vital part of past space manufacturing proposals, no one has proposed a lunar mining system in any real detail. The group considered it essential that the design of actual, workable, and specific lunar mining methods begin immediately. Based on an earlier proposal, the method is a three-drum slusher, also known as a cable-operated drag scraper. Its terrestrial application is quite limited, as it is relatively inefficient and inflexible. The method usually finds use in underwater mining from the shore and in moving small amounts of ore underground. When lunar mining scales up, the lunarized slusher will be replaced by more efficient, high-volume methods. Other aspects of lunar mining are discussed.

  1. Simulated and Virtual Science Laboratory Experiments: Improving Critical Thinking and Higher-Order Learning Skills

    NASA Astrophysics Data System (ADS)

    Simon, Nicole A.

    Virtual laboratory experiments using interactive computer simulations are not being employed as viable alternatives to laboratory science curriculum at extensive enough rates within higher education. Rote traditional lab experiments are currently the norm and are not addressing inquiry, Critical Thinking, and cognition throughout the laboratory experience, linking with educational technologies (Pyatt & Sims, 2007; 2011; Trundle & Bell, 2010). A causal-comparative quantitative study was conducted with 150 learners enrolled at a two-year community college, to determine the effects of simulation laboratory experiments on Higher-Order Learning, Critical Thinking Skills, and Cognitive Load. The treatment population used simulated experiments, while the non-treatment sections performed traditional expository experiments. A comparison was made using the Revised Two-Factor Study Process survey, Motivated Strategies for Learning Questionnaire, and the Scientific Attitude Inventory survey, using a Repeated Measures ANOVA test for treatment or non-treatment. A main effect of simulated laboratory experiments was found for both Higher-Order Learning, [F (1, 148) = 30.32,p = 0.00, eta2 = 0.12] and Critical Thinking Skills, [F (1, 148) = 14.64,p = 0.00, eta 2 = 0.17] such that simulations showed greater increases than traditional experiments. Post-lab treatment group self-reports indicated increased marginal means (+4.86) in Higher-Order Learning and Critical Thinking Skills, compared to the non-treatment group (+4.71). Simulations also improved the scientific skills and mastery of basic scientific subject matter. It is recommended that additional research recognize that learners' Critical Thinking Skills change due to different instructional methodologies that occur throughout a semester.

  2. Simulations towards optimization of a neutron/anti-neutron oscillation experiment at the European Spallation Source

    NASA Astrophysics Data System (ADS)

    Frost, Matthew; Kamyshkov, Yuri; Castellanos, Luis; Klinkby, Esben; US NNbar Collaboration

    2015-04-01

    The observation of Neutron/Anti-neutron oscillation would prove the existence of Baryon Number Violation (BNV), and thus an explanation for the dominance of matter over anti-matter in the universe. The latest experiments have shown the oscillation time to be greater than 8.6 x 107 seconds, whereas current theoretical predictions suggest times on the order of 108 to 109 seconds. A neutron oscillation experiment proposed at the European Spallation Source (ESS) would provide sensitivity of more than 1000 times previous experiments performed, thus providing a result well-suited to confirm or deny current theory. A conceptual design of the proposed experiment will be presented, as well as the optimization of key experiment components using Monte-Carlo simulation methods, including the McStas neutron ray-trace simulation package. This work is supported by the Organized Research Units Program funded by The University of Tennessee, Knoxville Office of Research and Engagement.

  3. Shifting Baselines, Science, and Society

    NASA Astrophysics Data System (ADS)

    Jackson, J. B.

    2006-12-01

    All of us have a deeply personal concept of nature based upon our childhood perceptions of the world around us, and of the subsequent degradation of nature by the experiences of our lifetimes. Yet even the most rudimentary knowledge of history clearly demonstrates that the modern rise of human population and consumption have wreaked havoc on global ecosystems to the extent that nowhere is close to natural or pristine and that most places have been increasingly degraded over many centuries. This disconnect between direct personal experience and abstract historical perspective is the problem of "shifting baselines" that is the fundamental impediment to basic scientific understanding and environmental policy, and affects scientists as much as the general public, business, and government. Scientists in particular suffer from the inability to directly observe and experimentally verify causes and effects of previous changes in ecosystems that now bear so little resemblance to their natural state. Under the circumstances, it is essential for scientists to draw scientific conclusions based on imperfect data and to publicly explain, defend, and discuss their conclusions as the best possible science given present information. The failure to do so makes science virtually irrelevant to social and environmental policy and government.

  4. Comprehensive comparisons of geodesic acoustic mode characteristics and dynamics between Tore Supra experiments and gyrokinetic simulations

    SciTech Connect

    Storelli, A. Vermare, L.; Hennequin, P.; Gürcan, Ö. D.; Singh, Rameswar; Morel, P.; Dif-Pradalier, G.; Sarazin, Y.; Garbet, X.; Grandgirard, V.; Ghendrih, P.; Görler, T.

    2015-06-15

    In a dedicated collisionality scan in Tore Supra, the geodesic acoustic mode (GAM) is detected and identified with the Doppler backscattering technique. Observations are compared to the results of a simulation with the gyrokinetic code GYSELA. We found that the GAM frequency in experiments is lower than predicted by simulation and theory. Moreover, the disagreement is higher in the low collisionality scenario. Bursts of non harmonic GAM oscillations have been characterized with filtering techniques, such as the Hilbert-Huang transform. When comparing this dynamical behaviour between experiments and simulation, the probability density function of GAM amplitude and the burst autocorrelation time are found to be remarkably similar. In the simulation, where the radial profile of GAM frequency is continuous, we observed a phenomenon of radial phase mixing of the GAM oscillations, which could influence the burst autocorrelation time.

  5. Nucleic acid polymeric properties and electrostatics: Directly comparing theory and simulation with experiment.

    PubMed

    Sim, Adelene Y L

    2016-06-01

    Nucleic acids are biopolymers that carry genetic information and are also involved in various gene regulation functions such as gene silencing and protein translation. Because of their negatively charged backbones, nucleic acids are polyelectrolytes. To adequately understand nucleic acid folding and function, we need to properly describe its i) polymer/polyelectrolyte properties and ii) associating ion atmosphere. While various theories and simulation models have been developed to describe nucleic acids and the ions around them, many of these theories/simulations have not been well evaluated due to complexities in comparison with experiment. In this review, I discuss some recent experiments that have been strategically designed for straightforward comparison with theories and simulation models. Such data serve as excellent benchmarks to identify limitations in prevailing theories and simulation parameters. PMID:26482088

  6. Plasmoids Formation During Simulations of Coaxial Helicity Injection in the National Spherical Torus Experiment.

    PubMed

    Ebrahimi, F; Raman, R

    2015-05-22

    The formation of an elongated Sweet-Parker current sheet and a transition to plasmoid instability has for the first time been predicted by simulations in a large-scale toroidal fusion plasma in the absence of any preexisting instability. Plasmoid instability is demonstrated through resistive MHD simulations of transient coaxial helicity injection experiments in the National Spherical Torus Experiment (NSTX). Consistent with the theory, fundamental characteristics of the plasmoid instability, including fast reconnection rate, have been observed in these realistic simulations. Motivated by the simulations, experimental camera images have been revisited and suggest the existence of reconnecting plasmoids in NSTX. Global, system-size plasmoid formation observed here should also have strong implications for astrophysical reconnection, such as rapid eruptive solar events. PMID:26047235

  7. Low-pressure electrical discharge experiment to simulate high-altitude lightning above thunderclouds

    NASA Technical Reports Server (NTRS)

    Jarzembski, M. A.; Srivastava, V.

    1995-01-01

    Recently, extremely interesting high-altitude cloud-ionosphere electrical discharges, like lightning above thunderstorms, have been observed from NASA's space shuttle missions and during airborne and ground-based experiments. To understand these discharges, a new experiment was conceived to simulate a thundercloud in a vacuum chamber using a dielectric in particulate form into which electrodes were inserted to create charge centers analogous to those in an electrified cloud. To represent the ionosphere, a conducting medium (metallic plate) was introduced at the top of the chamber. It was found that for different pressures between approximately 1 and 300 mb, corresponding to various upper atmospheric altitudes, different discharges occurred above the simulated thundercloud, and these bore a remarkable similarity to the observed atmospheric phenomena. At pressures greater than 300 mb, these discharges were rare and only discharges within the simulated thundercloud were observed. Use of a particulate dielectric was critical for the successful simulation of the high-altitude lightning.

  8. Microwave Transmission Through the Electron Cloud at the Fermilab Main Injector: Simulation and Comparison with Experiment

    SciTech Connect

    Lebrun, Paul L.G.; Veitzer, Seth Andrew; /Tech-X, Boulder

    2009-04-01

    Simulations of the microwave transmission properties through the electron cloud at the Fermilab Main Injector have been implemented using the plasma simulation code 'VORPAL'. Phase shifts and attenuation curves have been calculated for the lowest frequency TE mode, slightly above the cutoff frequency, in field free regions, in the dipoles and quadrupoles. Preliminary comparisons with experimental results for the dipole case are showed and will guide the next generation of experiments.

  9. Salton Sea sampling program: baseline studies

    SciTech Connect

    Tullis, R.E.; Carter, J.L.; Langlois, G.W.

    1981-04-13

    Baseline data are provided on three species of fish from the Salton Sea, California. The fishes considered were the orange mouth corvina (Cynoscion xanthulus), gulf croaker (Bairdiella icistius) and sargo (Anisotremus davidsonii). Morphometric and meristic data are presented as a baseline to aid in the evaluation of any physiological stress the fish may experience as a result of geothermal development. Analyses were made on muscle, liver, and bone of the fishes sampled to provide baseline data on elemental tissue burdens. The elements measured were: As, Br, Ca, Cu, Fe, Ga, K, Mn, Mi, Pb, Rb, Se, Sr, Zn, and Zr. These data are important if an environmentally sound progression of geothermal power production is to occur at the Salton Sea.

  10. Comparing Fast Pressure Jump and Temperature Jump Protein Folding Experiments and Simulations

    PubMed Central

    Prigozhin, Maxim B.; Schulten, Klaus; Gruebele, Martin

    2016-01-01

    The unimolecular folding reaction of small proteins is now amenable to a very direct mechanistic comparison between experiment and simulation. We present such a comparison of microsecond pressure and temperature jump refolding kinetics of the engineered WW domain FiP35, a model system for beta sheet folding. Both perturbations produce experimentally a faster and a slower kinetic phase, the “slow” microsecond phase being activated. The fast phase shows differences between perturbation methods and is closer to the downhill limit by temperature jump, but closer to the transiently populated intermediate limit by pressure jump. These observations make more demands on simulations of the folding process than just a rough comparison of time scales. To complement experiments, we calculated several pressure jump and temperature jump all-atom molecular dynamics trajectories in explicit solvent, where FiP35 folded in five of the six simulations. We analyzed our pressure jump simulations by kinetic modeling and found that the pressure jump experiments and MD simulations are most consistent with a 4-state kinetic mechanism. Together, our experimental and computational data highlight FiP35’s position at the boundary where activated intermediates and downhill folding meet, and we show that this model protein is an excellent candidate for further pressure jump molecular dynamics studies to compare experiment and modeling at the folding mechanism level. PMID:25988868

  11. Dynamical fingerprints for probing individual relaxation processes in biomolecular dynamics with simulations and kinetic experiments

    SciTech Connect

    Noe, F; Diadone, Isabella; Lollmann, Marc; Sauer, Marcus; Chondera, John D; Smith, Jeremy C

    2011-01-01

    There is a gap between kinetic experiment and simulation in their views of the dynamics of complex biomolecular systems. Whereas experiments typically reveal only a few readily discernible exponential relaxations, simulations often indicate complex multistate behavior. Here, a theoretical framework is presented that reconciles these two approaches. The central concept is dynamical fingerprints which contain peaks at the time scales of the dynamical processes involved with amplitudes determined by the experimental observable. Fingerprints can be generated from both experimental and simulation data, and their comparison by matching peaks permits assignment of structural changes present in the simulation to experimentally observed relaxation processes. The approach is applied here to a test case interpreting single molecule fluorescence correlation spectroscopy experiments on a set of fluorescent peptides with molecular dynamics simulations. The peptides exhibit complex kinetics shown to be consistent with the apparent simplicity of the experimental data. Moreover, the fingerprint approach can be used to design new experiments with site-specific labels that optimally probe specific dynamical processes in the molecule under investigation.

  12. Simulation and experiment of soft-tissue deformation in prostate brachytherapy.

    PubMed

    Liang, Dong; Jiang, Shan; Yang, Zhiyong; Wang, Xingji

    2016-06-01

    Soft-tissue deformation is one of the major reasons for the inaccurate positioning of percutaneous needle insertion process. In this article, simulations and experiments of the needle insertion soft-tissue process are both applied to study soft-tissue deformation. A needle deflection model based on the mechanics is used to calculate the needle deflection during the interaction process. The obtained needle deflection data are applied into finite element analysis process as the system input. The uniaxial tensile strength tests, compression tests, and static indentation experiments are used to obtain the soft-tissue parameters and choose the best strain-energy function to model in the simulation. Magnetic resonance imaging is used to reconstruct the prostate, establishing both prostate three-dimensional finite element model and artificial prostate model. The needle-soft tissue interaction simulation results are compared with those of the needle insertion experiment. The displacement data of the mark point in the experiment are comparable to the simulation results. It is concluded that, using this simulation method, the surgeon can predict the deformation of the tissue and the displacement of the target in advance. PMID:27129384

  13. Computer Simulation and Field Experiment for Downlink Multiuser MIMO in Mobile WiMAX System

    PubMed Central

    Yamaguchi, Kazuhiro; Nagahashi, Takaharu; Akiyama, Takuya; Matsue, Hideaki; Uekado, Kunio; Namera, Takakazu; Fukui, Hiroshi; Nanamatsu, Satoshi

    2015-01-01

    The transmission performance for a downlink mobile WiMAX system with multiuser multiple-input multiple-output (MU-MIMO) systems in a computer simulation and field experiment is described. In computer simulation, a MU-MIMO transmission system can be realized by using the block diagonalization (BD) algorithm, and each user can receive signals without any signal interference from other users. The bit error rate (BER) performance and channel capacity in accordance with modulation schemes and the number of streams were simulated in a spatially correlated multipath fading environment. Furthermore, we propose a method for evaluating the transmission performance for this downlink mobile WiMAX system in this environment by using the computer simulation. In the field experiment, the received power and downlink throughput in the UDP layer were measured on an experimental mobile WiMAX system developed in Azumino City in Japan. In comparison with the simulated and experimented results, the measured maximum throughput performance in the downlink had almost the same performance as the simulated throughput. It was confirmed that the experimental mobile WiMAX system for MU-MIMO transmission successfully increased the total channel capacity of the system. PMID:26421311

  14. Computer Simulation and Field Experiment for Downlink Multiuser MIMO in Mobile WiMAX System.

    PubMed

    Yamaguchi, Kazuhiro; Nagahashi, Takaharu; Akiyama, Takuya; Matsue, Hideaki; Uekado, Kunio; Namera, Takakazu; Fukui, Hiroshi; Nanamatsu, Satoshi

    2015-01-01

    The transmission performance for a downlink mobile WiMAX system with multiuser multiple-input multiple-output (MU-MIMO) systems in a computer simulation and field experiment is described. In computer simulation, a MU-MIMO transmission system can be realized by using the block diagonalization (BD) algorithm, and each user can receive signals without any signal interference from other users. The bit error rate (BER) performance and channel capacity in accordance with modulation schemes and the number of streams were simulated in a spatially correlated multipath fading environment. Furthermore, we propose a method for evaluating the transmission performance for this downlink mobile WiMAX system in this environment by using the computer simulation. In the field experiment, the received power and downlink throughput in the UDP layer were measured on an experimental mobile WiMAX system developed in Azumino City in Japan. In comparison with the simulated and experimented results, the measured maximum throughput performance in the downlink had almost the same performance as the simulated throughput. It was confirmed that the experimental mobile WiMAX system for MU-MIMO transmission successfully increased the total channel capacity of the system. PMID:26421311

  15. Neutron Emission Characteristics of Two Mixed-Oxide Fuels: Simulations and Initial Experiments

    SciTech Connect

    D. L. Chichester; S. A. Pozzi; J. L. Dolan; M. Flaska; J. T. Johnson; E. H. Seabury; E. M. Gantz

    2009-07-01

    Simulations and experiments have been carried out to investigate the neutron emission characteristics of two mixed-oxide (MOX) fuels at Idaho National Laboratory (INL). These activities are part of a project studying advanced instrumentation techniques in support of the U.S. Department of Energy's Fuel Cycle Research and Development program and it's Materials Protection, Accounting, and Control for Transmutation (MPACT) campaign. This analysis used the MCNP-PoliMi Monte Carlo simulation tool to determine the relative strength and energy spectra of the different neutron source terms within these fuels, and then used this data to simulate the detection and measurement of these emissions using an array of liquid scintillator neutron spectrometers. These calculations accounted for neutrons generated from the spontaneous fission of the actinides in the MOX fuel as well as neutrons created via (alpha,n) reactions with oxygen in the MOX fuel. The analysis was carried out to allow for characterization of both neutron energy as well as neutron coincidences between multiple detectors. Coincidences between prompt gamma rays and neutrons were also analyzed. Experiments were performed at INL with the same materials used in the simulations to benchmark and begin validation tests of the simulations. Data was collected in these experiments using an array of four liquid scintillators and a high-speed waveform digitizer. Advanced digital pulse-shape discrimination algorithms were developed and used to collect this data. Results of the simulation and modeling studies are presented together with preliminary results from the experimental campaign.

  16. Simulation Experiment Description Markup Language (SED-ML) Level 1 Version 2.

    PubMed

    Bergmann, Frank T; Cooper, Jonathan; Le Novère, Nicolas; Nickerson, David; Waltemath, Dagmar

    2015-01-01

    The number, size and complexity of computational models of biological systems are growing at an ever increasing pace. It is imperative to build on existing studies by reusing and adapting existing models and parts thereof. The description of the structure of models is not sufficient to enable the reproduction of simulation results. One also needs to describe the procedures the models are subjected to, as recommended by the Minimum Information About a Simulation Experiment (MIASE) guidelines. This document presents Level 1 Version 2 of the Simulation Experiment Description Markup Language (SED-ML), a computer-readable format for encoding simulation and analysis experiments to apply to computational models. SED-ML files are encoded in the Extensible Markup Language (XML) and can be used in conjunction with any XML-based model encoding format, such as CellML or SBML. A SED-ML file includes details of which models to use, how to modify them prior to executing a simulation, which simulation and analysis procedures to apply, which results to extract and how to present them. Level 1 Version 2 extends the format by allowing the encoding of repeated and chained procedures. PMID:26528560

  17. FLASH hydrodynamic simulations of experiments to explore the generation of cosmological magnetic fields

    NASA Astrophysics Data System (ADS)

    Scopatz, A.; Fatenejad, M.; Flocke, N.; Gregori, G.; Koenig, M.; Lamb, D. Q.; Lee, D.; Meinecke, J.; Ravasio, A.; Tzeferacos, P.; Weide, K.; Yurchak, R.

    2013-03-01

    We report the results of FLASH hydrodynamic simulations of the experiments conducted by the University of Oxford High Energy Density Laboratory Astrophysics group and its collaborators at the Laboratoire pour l'Utilisation de Lasers Intenses (LULI). In these experiments, a long-pulse laser illuminates a target in a chamber filled with Argon gas, producing shock waves that generate magnetic fields via the Biermann battery mechanism. The simulations show that the result of the laser illuminating the target is a series of complex hydrodynamic phenomena.

  18. Calculation of Dose Deposition in Nanovolumes and Simulation of gamma-H2AX Experiments

    NASA Technical Reports Server (NTRS)

    Plante, Ianik

    2010-01-01

    Monte-Carlo track structure simulations can accurately simulate experimental data: a) Frequency of target hits. b) Dose per event. c) Dose per ion. d) Radial dose. The dose is uniform in micrometers sized voxels; at the nanometer scale, the difference in energy deposition between high and low-LET radiations appears. The calculated 3D distribution of dose voxels, combined with chromosomes simulated by random walk is very similar to the distribution of DSB observed with gamma-H2AX experiments. This is further evidenced by applying a visualization threshold on dose.

  19. Nonlinear soil-structure interaction calculations simulating the SIMQUAKE experiment using STEALTH 2D

    NASA Technical Reports Server (NTRS)

    Tang, H. T.; Hofmann, R.; Yee, G.; Vaughan, D. K.

    1980-01-01

    Transient, nonlinear soil-structure interaction simulations of an Electric Power Research Institute, SIMQUAKE experiment were performed using the large strain, time domain STEALTH 2D code and a cyclic, kinematically hardening cap soil model. Results from the STEALTH simulations were compared to identical simulations performed with the TRANAL code and indicate relatively good agreement between all the STEALTH and TRANAL calculations. The differences that are seen can probably be attributed to: (1) large (STEALTH) vs. small (TRANAL) strain formulation and/or (2) grid discretization differences.

  20. Numerical simulations of a nonequilibrium argon plasma in a shock-tube experiment

    NASA Technical Reports Server (NTRS)

    Cambier, Jean-Luc

    1991-01-01

    A code developed for the numerical modeling of nonequilibrium radiative plasmas is applied to the simulation of the propagation of strong ionizing shock waves in argon gas. The simulations attempt to reproduce a series of shock-tube experiments which will be used to validate the numerical models and procedures. The ability to perform unsteady simulations makes it possible to observe some fluctuations in the shock propagation, coupled to the kinetic processes. A coupling mechanism by pressure waves, reminiscent of oscillation mechanisms observed in detonation waves, is described. The effect of upper atomic levels is also briefly discussed.

  1. A numerical tool for reproducing driver behaviour: experiments and predictive simulations.

    PubMed

    Casucci, M; Marchitto, M; Cacciabue, P C

    2010-03-01

    This paper presents the simulation tool called SDDRIVE (Simple Simulation of Driver performance), which is the numerical computerised implementation of the theoretical architecture describing Driver-Vehicle-Environment (DVE) interactions, contained in Cacciabue and Carsten [Cacciabue, P.C., Carsten, O. A simple model of driver behaviour to sustain design and safety assessment of automated systems in automotive environments, 2010]. Following a brief description of the basic algorithms that simulate the performance of drivers, the paper presents and discusses a set of experiments carried out in a Virtual Reality full scale simulator for validating the simulation. Then the predictive potentiality of the tool is shown by discussing two case studies of DVE interactions, performed in the presence of different driver attitudes in similar traffic conditions. PMID:19249745

  2. Monte Carlo simulations of multiple scattering effects in laser assisted free-free scattering experiments

    NASA Astrophysics Data System (ADS)

    Deharak, B. A.; Savich, J. L.; Roberts, H. M.; Brown, E. G.; McGill, M. R.; Kim, B. N.; Weaver, C. M.; Martin, N. L. S.

    2016-05-01

    We have conducted a series of Monte Carlo simulations of laser assisted free-free scattering experiments. The simulations make use of Kroll-Watson approximation to account for the effects of the laser field on the scattering process. The parameters for these simulations are believed to mimic the experimental conditions of the work reported by Wallbank and Holmes, particularly the target number density. The simulations account for the effects multiple scattering (i.e., the scattering of a single incident electron from multiple target atoms). We present a comparison of the results of these simulations to the experimental results of Wallbank and Holmes. This work was supported by the National Science Foundation under Grants Nos. PHY-0855040 (NLSM) and PHY-1402899 (BAd).

  3. The latest results from ELM-simulation experiments in plasma accelerators

    NASA Astrophysics Data System (ADS)

    Garkusha, I. E.; Arkhipov, N. I.; Klimov, N. S.; Makhlaj, V. A.; Safronov, V. M.; Landman, I.; Tereshin, V. I.

    2009-12-01

    Recent results of ELM-simulation experiments with quasi-stationary plasma accelerators (QSPAs) Kh-50 (Kharkov, Ukraine) and QSPA-T (Troitsk, Russia) as well as experiments in the pulsed plasma gun MK-200UG (Troitsk, Russia) are discussed. Primary attention in Troitsk experiments has been focused on investigating the carbon-fibre composite (CFC) and tungsten erosion mechanisms, their onset conditions and the contribution of various erosion mechanisms (including droplet splashing) to the resultant surface damage at varying plasma heat flux. The obtained results are used for validating the numerical codes PEGASUS and MEMOS developed in FZK. Crack patterns and residual stresses in tungsten targets under repetitive edge localized mode (ELM)-like plasma pulses are studied in simulation experiments with QSPA Kh-50. Statistical processing of the experimental results on crack patterns after different numbers of QSPA Kh-50 exposures as well as those on the dependence of cracking on the heat load and surface temperature is performed.

  4. Coffee husk mulch on soil erosion and runoff: experiences under rainfall simulation experiment

    NASA Astrophysics Data System (ADS)

    Moreno-Ramón, H.; Quizembe, S. J.; Ibáñez-Asensio, S.

    2014-05-01

    The high erosion rates found in the agriculture land make valuable the use of mulches to control the soil and water losses. Coffee husk (Coffee canephora var. robusta) can be one of those mulches. This paper evaluates how to apply the mulch in order to obtain, with the same doses, the best effectiveness. An experimental factorial design 4 × 3 × 2 with two replicates was designed in a greenhouse with a total amount of 48 treatments. All the samples were deposited in trays of 0.51 m2 and applied a simulated rain of 122 mm h-1 during 21 min. The factors examined were: four soil classes; three treatments: buried (B), surface (S) and non-residue (C), and the presence (WC) or absence (WOC) of the soil surface crusting. The coffee husk residue (S and B treatments) reduced runoff by 10.2% and 46% respectively, soil losses by 78.3% and 88.7% and sediment concentration by 77% and 84.4%. The infiltration rate increased on average by 104% and 167%, and time to runoff by 1.58 and 2.07 min respectively. The coffee husk mulch (S and B) avoided the influence of crust. Coffee husk is an efficient mulch to reduce the soil and water losses.

  5. Coffee husk mulch on soil erosion and runoff: experiences under rainfall simulation experiment

    NASA Astrophysics Data System (ADS)

    Moreno-Ramón, H.; Quizembe, S. J.; Ibáñez-Asensio, S.

    2014-08-01

    The high erosion rates found in the agriculture land make valuable the use of mulches to control the soil and water losses. Coffee husk (Coffea canephora var. robusta) can be one of those mulches. This paper evaluates how to apply the mulch in order to obtain the best effectiveness. An experimental factorial design 4 × 3 × 2 with two replicates was designed in a greenhouse with a total number of 48 cases. All the samples were deposited in trays of 0.51 m2 and applied a simulated rain of 122 mm h-1 during 21 min. The factors examined were the following: four soil classes; three treatments - buried (B), surface (S) and non-residue (C) - and the presence (WC) or absence (WOC) of the soil surface crusting. The coffee husk residue (S and B treatments) reduced runoff by 10.2 and 46% respectively, soil losses by 78.3 and 88.7% and sediment concentration by 77 and 84.4%. The infiltration rate increased on average by 104 and 167%, and time to runoff by 1.58 and 2.07 min respectively. Coffee husk is an efficient mulch to reduce the soil and water losses, although it could not completely cushion the influence of crust.

  6. The Effectiveness of Using Computer Simulated Experiments on Junior High Students' Understanding of the Volume Displacement Concept.

    ERIC Educational Resources Information Center

    Choi, Byung-Soon; Gennaro, Eugene

    1987-01-01

    Reports on a study which compared the effectiveness of microcomputer simulated experiences with that of parallel, hands-on laboratory instruction for teaching the concept of volume displacement to junior high school students. Results indicated that computer simulated experience were as affective as hands-on laboratory experiences. (TW)

  7. Baseline Familiarity in Lie Detection.

    ERIC Educational Resources Information Center

    Feeley, Thomas H.; And Others

    1995-01-01

    Reports on a study in which subjects judged the veracity of truthful and deceptive communicators after viewing no, one, two, or four case-relevant baseline exposures (familiarity) of truthful communication. Finds a positive linear relationship between detection accuracy and amount of baseline familiarity. (SR)

  8. Simulation: a shared learning experience for child and mental health pre-registration nursing students.

    PubMed

    Felton, Anne; Holliday, Laura; Ritchie, Dawn; Langmack, Gill; Conquer, Alistair

    2013-11-01

    Learning through the use of simulation is perceived as an innovative means to help manage some of the contemporary challenges for pre-registration nurse education. Mental health and child nurses need to have the knowledge and skills to effectively address the holistic needs of service users. This article reports on a pilot simulated learning experience that was designed with key stakeholders for pre-registration child and mental health nursing students. This involved young actors playing the role of someone who had self-harmed to help students develop their skills for working with young people who experience emotional distress. Focus groups and a questionnaire were used to evaluate the pilot. Students valued the practical approach that simulation entailed and identified the benefits of the shared learning experience across the different fields of practice of nursing. However, some students reported anxiety performing in front of peers and indicated they would perform differently in practice. The pilot identified simulation as a potentially useful approach to help child and mental health student nurses develop skills for caring for young people. However, there is a need for caution in the claims to be made regarding the impact of simulation to address gaps in nursing skills. PMID:23660414

  9. Simulations of Experiments on Electron Magnetohydrodynamic Reconnection in a Field Reversed Configuration

    NASA Astrophysics Data System (ADS)

    Correa, Cynthia; Horton, Wendel

    2012-10-01

    Theory and simulations are developed to interpret laboratory electron magnetohydrodynamic reconnection experiments involving nonlinear whistlers by Stenzel et.al. [R.L. Stenzel, M.C. Griskey, J. M. Urrutia, and K.D. Strohmaier, Phys. Plasma 10, 2780 (2003)]. In that experiment, two current-carrying 30 cm antennas form a Helmholtz coil configuration and produce an elongated dipole field that opposes the uniform ambient field. The current is increased until a field-reversed-configuration with two 3D null points and a 2D null line has been established, and then the current is switched off. The EMHD dynamics are simulated with a 3D three-field nonlinear MHD code. The analytical model includes Poisson bracket nonlinearities that can give rise to vortices and couple energy to higher modes, as well as hyperviscosity to balance the energy exchange. Simulation field topology and dynamics are compared to the laboratory experiment as verification of the simulation code. The experimental setup and other variations are simulated and examined for occurrences of driven and undriven electron magnetohydrodynamic (EMHD) reconnection.

  10. Dispersing Zwitterions into Comb Polymers for Nonviral Transfection: Experiments and Molecular Simulation.

    PubMed

    Ghobadi, Ahmadreza F; Letteri, Rachel; Parelkar, Sangram S; Zhao, Yue; Chan-Seng, Delphine; Emrick, Todd; Jayaraman, Arthi

    2016-02-01

    Polymer-based gene delivery vehicles benefit from the presence of hydrophilic groups that mitigate the inherent toxicity of polycations and that provide tunable polymer-DNA binding strength and stable complexes (polyplexes). However, hydrophilic groups screen charge, and as such can reduce cell uptake and transfection efficiency. We report the effect of embedding zwitterionic sulfobetaine (SB) groups in cationic comb polymers, using a combination of experiments and molecular simulations. Ring-opening metathesis polymerization (ROMP) produced comb polymers with tetralysine (K4) and SB pendent groups. Dynamic light scattering, zeta potential measurements, and fluorescence-based experiments, together with coarse-grained molecular dynamics simulations, described the effect of SB groups on the size, shape, surface charge, composition, and DNA binding strength of polyplexes formed using these comb polymers. Experiments and simulations showed that increasing SB composition in the comb polymers decreased polymer-DNA binding strength, while simulations indicated that the SB groups distributed throughout the polyplex. This allows polyplexes to maintain a positive surface charge and provide high levels of gene expression in live cells. Notably, comb polymers with nearly 50 mol % SB form polyplexes that exhibit positive surface charge similarly as polyplexes formed from purely cationic comb polymers, indicating the ability to introduce an appreciable amount of SB functionality without screening surface charge. This integrated simulation-experimental study demonstrates the effectiveness of incorporating zwitterions in polyplexes, while guiding the design of new and effective gene delivery vectors. PMID:26741292

  11. Mental simulation and experience as determinants of performance expectancies in people with schizophrenia spectrum disorder.

    PubMed

    Huddy, Vyv; Drake, Gareth; Wykes, Til

    2016-03-30

    People with schizophrenia demonstrate both impairment in mental time travel and reduced expectancies of performance on future tasks. We aimed to reconcile these findings within the Kahneman and Tversky (1982) simulation heuristic framework by testing a key prediction that impaired future simulation would be associated with reduced performance expectancies in people with schizophrenia spectrum disorder (SZSPEC). A total of 54 individuals (30 people with SZSPEC and 24 healthy controls) generated mental simulations of everyday scenarios; after each response they rated performance expectations, distress and the similarity of the scenario to experience. Independent raters coded the coherence of responses. We found that people with SZSPEC had, compared to healthy controls, lower performance expectations and greater anticipated distress when imaging everyday scenarios. Lower performance expectancies were associated with lower experience of similar scenarios, greater negative symptoms and social withdrawal in the SZSPEC group. The current study confirmed previous findings of both impaired mental simulation and abnormal performance expectations in people with SZSPEC, together with the association of the latter with negative symptoms. Experience with social or occupational activities plays a more important role in determining performance expectancies in people with SS than the ability to mentally simulate scenarios. PMID:26921059

  12. Simulation and modeling of the Gamble II self-pinched ion beam transport experiment

    SciTech Connect

    Rose, D.V.; Ottinger, P.F.; Hinshelwood, D.D.

    1999-07-01

    Progress in numerical simulations and modeling of the self-pinched ion beam transport experiment at the Naval Research Laboratory (NRL) is reviewed. In the experiment, a 1.2-MeV, 100-kA proton beam enters a 1-m long, transport region filled with a low pressure gas (30--250 mTorr helium, or 1 Torr air). The time-dependent velocity distribution function of the injected ion beam is determined from an orbit code that uses a pinch-reflex ion diode model and the measured voltage and current from this diode on the Gamble II generator at NRL. This distribution function is used as the beam input condition for numerical simulations carried out using the hybrid particle-in-cell code IPROP. Results of the simulations will be described, and detailed comparisons will be made with various measurements, including line-integrated electron-density, proton-fluence, and beam radial-profile measurements. As observed in the experiment, the simulations show evidence of self-pinching for helium pressures between 35 and 80 mTorr. Simulations and measurements in 1 Torr air show ballistic transport. The relevance of these results to ion-driven inertial confinement fusion will be discussed.

  13. Plutonium Immobilization Project Baseline Formulation

    SciTech Connect

    Ebbinghaus, B.

    1999-02-01

    A key milestone for the Immobilization Project (AOP Milestone 3.2a) in Fiscal Year 1998 (FY98) is the definition of the baseline composition or formulation for the plutonium ceramic form. The baseline formulation for the plutonium ceramic product must be finalized before the repository- and plant-related process specifications can be determined. The baseline formulation that is currently specified is given in Table 1.1. In addition to the baseline formulation specification, this report provides specifications for two alternative formulations, related compositional specifications (e.g., precursor compositions and mixing recipes), and other preliminary form and process specifications that are linked to the baseline formulation. The preliminary specifications, when finalized, are not expected to vary tremendously from the preliminary values given.

  14. The Impact of Simulation-Based Learning Experience on Critical Thinking Acquisition

    ERIC Educational Resources Information Center

    Rome, Candice

    2012-01-01

    The purpose of this comparative experimental project was to compare the impact of simulation-based learning experiences to traditional clinical rotations on critical thinking acquisition of associate nursing students within a maternal-child course. Innovative pedagogies have been integrated in nursing programs to augment inadequate clinical…

  15. Simulation and Experiment of Extinction or Adaptation of Biological Species after Temperature Changes

    NASA Astrophysics Data System (ADS)

    Stauffer, D.; Arndt, H.

    Can unicellular organisms survive a drastic temperature change, and adapt to it after many generations? In simulations of the Penna model of biological aging, both extinction and adaptation were found for asexual and sexual reproduction as well as for parasex. These model investigations are the basis for the design of evolution experiments with heterotrophic flagellates.

  16. An observing system simulation experiment (OSSE) for the aquarius/SAC-D soil moisture product

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An Observing System Simulation Experiment for the Aquarius/SAC-D mission has been developed for assessing the accuracy of soil moisture retrievals from passive L-band remote sensing. The implementation of the OSSE is based on: a 1-km land surface model over the Red-Arkansas River Basin, a forward mi...

  17. Expanding the Lester Hill Experience: A Report on Two 'Branch Office' Simulations

    ERIC Educational Resources Information Center

    Melvin, Opal B.

    1976-01-01

    Describes use of the Lester Hill Office Simulation, a program taught at the Tishomingo County Area Vocational-Technical Center in Mississippi. A fictitious company which provides students with the opportunity to gain realistic office experience in a classroom setting. Suggested ideas and optional activities can be used by teachers as a starting…

  18. Segment-level evaluation of the simulated aggregation test: US corn and soybean exploratory experiment

    NASA Technical Reports Server (NTRS)

    Davidson, S. A. (Principal Investigator)

    1980-01-01

    An evaluation of the corn and soybean proportion-estimation accuracy and dot labeling accuracy of the Simulated Aggregation Test, U.S. Corn and Soybean Exploratory Experiment, is presented. These results are in turn compared with the corn and soybean proportion-estimation accuracy and dot labeling accuracy of the Classification Procedures Verification Test.

  19. Simultaneous Epicardial and Noncontact Endocardial Mapping of the Canine Right Atrium: Simulation and Experiment

    PubMed Central

    Sabouri, Sepideh; Matene, Elhacene; Vinet, Alain; Richer, Louis-Philippe; Cardinal, René; Armour, J. Andrew; Pagé, Pierre; Kus, Teresa; Jacquemet, Vincent

    2014-01-01

    Epicardial high-density electrical mapping is a well-established experimental instrument to monitor in vivo the activity of the atria in response to modulations of the autonomic nervous system in sinus rhythm. In regions that are not accessible by epicardial mapping, noncontact endocardial mapping performed through a balloon catheter may provide a more comprehensive description of atrial activity. We developed a computer model of the canine right atrium to compare epicardial and noncontact endocardial mapping. The model was derived from an experiment in which electroanatomical reconstruction, epicardial mapping (103 electrodes), noncontact endocardial mapping (2048 virtual electrodes computed from a 64-channel balloon catheter), and direct-contact endocardial catheter recordings were simultaneously performed in a dog. The recording system was simulated in the computer model. For simulations and experiments (after atrio-ventricular node suppression), activation maps were computed during sinus rhythm. Repolarization was assessed by measuring the area under the atrial T wave (ATa), a marker of repolarization gradients. Results showed an epicardial-endocardial correlation coefficients of 0.80 and 0.63 (two dog experiments) and 0.96 (simulation) between activation times, and a correlation coefficients of 0.57 and 0.46 (two dog experiments) and 0.92 (simulation) between ATa values. Despite distance (balloon-atrial wall) and dimension reduction (64 electrodes), some information about atrial repolarization remained present in noncontact signals. PMID:24598778

  20. Instant Experience in Clinical Trials: A Computer-Aided Simulation Technique

    ERIC Educational Resources Information Center

    Simpson, Michael A.

    1976-01-01

    Describes "Instant Experience," a simulation and game method in which students are given information about a promising new drug and asked to design a protocol for a clinical trial of the drug. Evaluation of a trial workshop showed positive response to the method. Educational goals to be achieved through its use are noted. (JT)