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 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.

  3. Long-Baseline Neutrino Experiments

    SciTech Connect

    Diwan, M. V.; Galymov, V.; Qian, X.; Rubbia, A.

    2016-10-19

    We review long-baseline neutrino experiments in which neutrinos are detected after traversing macroscopic distances. Over such distances neutrinos have been found to oscillate among flavor states. Experiments with solar, atmospheric, reactor, and accelerator neutrinos have resulted in a coherent picture of neutrino masses and mixing of the three known flavor states. We will summarize the current best knowledge of neutrino parameters and phenomenology with our focus on the evolution of the experimental technique. We will proceed from the rst evidence produced by astrophysical neutrino sources to the current open questions and the goals of future research

  4. 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.

  5. Baseline experiments in teleoperator control

    NASA Technical Reports Server (NTRS)

    Hankins, W. W., III; Mixon, R. W.

    1986-01-01

    Studies have been conducted at the NASA Langley Research Center (LaRC) to establish baseline human teleoperator interface data and to assess the influence of some of the interface parameters on human performance in teleoperation. As baseline data, the results will be used to assess future interface improvements resulting from this research in basic teleoperator human factors. In addition, the data have been used to validate LaRC's basic teleoperator hardware setup and to compare initial teleoperator study results. Four subjects controlled a modified industrial manipulator to perform a simple task involving both high and low precision. Two different schemes for controlling the manipulator were studied along with both direct and indirect viewing of the task. Performance of the task was measured as the length of time required to complete the task along with the number of errors made in the process. Analyses of variance were computed to determine the significance of the influences of each of the independent variables. Comparisons were also made between the LaRC data and data taken earlier by Grumman Aerospace Corp. at their facilities.

  6. Long Baseline Neutrino Experiment Sensitivity Studies

    NASA Astrophysics Data System (ADS)

    Norrick, Anne; LBNE Collaboration

    2011-04-01

    The Long Baseline Neutrino Experiment (LBNE) will address the neutrino mass hierarchy, leptonic CP violation, and the value of the mixing angle Theta13 with unprecedented sensitivity. Protons from the Fermilab Main Injector will impinge on a target to create intense fluxes of charged pions and other mesons. The mesons will be guided down a 250 m length of pipe where they will decay creating a muon neutrino beam. The beam will pass through a near detector and travel on to massive detectors located in the Deep Underground Science and Engineering Lab (DUSEL) in Western South Dakota. The near detector at Fermilab will measure the absolute flux of neutrinos before oscillation, and measure signal and background processes in the poorly understood GeV neutrino energy range. To quantify the potential sensitivity of this experiment and the specific needs of the near detector, simulation work has been undertaken. In particular, results of studies using a more sophisticated understanding of various background processes will be presented. Additionally, hardware work for a possible near detector design will be presented.

  7. Systematic errors in long baseline oscillation experiments

    SciTech Connect

    Harris, Deborah A.; /Fermilab

    2006-02-01

    This article gives a brief overview of long baseline neutrino experiments and their goals, and then describes the different kinds of systematic errors that are encountered in these experiments. Particular attention is paid to the uncertainties that come about because of imperfect knowledge of neutrino cross sections and more generally how neutrinos interact in nuclei. Near detectors are planned for most of these experiments, and the extent to which certain uncertainties can be reduced by the presence of near detectors is also discussed.

  8. 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.

  9. 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.

  10. 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)

  11. The OPERA long baseline neutrino oscillation experiment

    NASA Astrophysics Data System (ADS)

    Wilquet, G.

    2008-05-01

    OPERA is a long baseline neutrino oscillation experiment designed to observe the appearance of vτ in a pure vμ beam in the parameter space indicated by the atmospheric neutrinos oscillation signal. The detector is situated in the underground LNGS laboratory under 3 800 water meter equivalent at a distance of 730 km from CERN where the CNGS neutrino beam to which it is exposed originates. It consists of two identical 0.68 kilotons lead/nuclear emulsion targets, each instrumented with a tracking device and complemented by a muon spectrometer. The concept and the status of the detector are described and the first results obtained with cosmic rays and during two weeks of beam commissioning in 2006 are reported.

  12. 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.

  13. Prospects for long baseline neutrino oscillation experiments

    SciTech Connect

    Goodman, M.

    1991-12-31

    Several recent development have motivated consideration of neutrino experiments located hundreds or thousand of kilometers from an accelerator. The motivations and experimental challenges for such experiments are examined. Three proposals for using the Fermilab Main Injector are compared. The requirements on mass, distance and resolution for an ``ideal`` detector for such an experimental are considered.

  14. Prospects for long baseline neutrino oscillation experiments

    SciTech Connect

    Goodman, M.

    1991-01-01

    Several recent development have motivated consideration of neutrino experiments located hundreds or thousand of kilometers from an accelerator. The motivations and experimental challenges for such experiments are examined. Three proposals for using the Fermilab Main Injector are compared. The requirements on mass, distance and resolution for an ideal'' detector for such an experimental are considered.

  15. 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.

  16. 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.

  17. 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.

  18. Long-baseline neutrino oscillation experiments in North America

    SciTech Connect

    Goodman, M. C.

    2009-03-01

    This contribution to the proceedings of the 2008 NOW Workshop summarizes current and future long-baseline neutrino oscillation experiments in the United States. Together with recent results from MINOS, a future program incorporating NOvA and a long-baseline beam from Fermilab to DUSEL represents one possible scenario for a future U.S. High Energy Physics program with a significant neutrino component. Other futures are also possible. Depending on the value of {theta}{sub 13}, we may find that the future involves serious consideration of intercontinental neutrino beams, with the concomitant additional challenges in planning within an international framework.

  19. 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.

  20. Prospects for next generation long-baseline oscillation experiments

    SciTech Connect

    Deborah A Harris

    2003-06-17

    This document describes some of the exciting possibilities for the next steps in the field of long baseline neutrino oscillation measurements. Because the primary goals of these new experiments are so different from those of the current generation, one cannot simply increase the running time or detector mass of the current programs. There are several new strategies which have been discussed for taking the next steps: sometimes the detectors, sometimes the beamlines, and sometimes both are radically different from what is now in place.

  1. 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.

  2. 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.

  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. 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.

  6. The Effects of Attrition on Baseline Comparability in Randomized Experiments in Education: A Meta-Analysis

    ERIC Educational Resources Information Center

    Valentine, Jeffrey C.; McHugh, Cathleen M.

    2007-01-01

    Using meta-analysis, randomized experiments in education that either clearly did or clearly did not experience student attrition were examined for the baseline comparability of groups. Results from 35 studies suggested that after attrition, the observed measures of baseline comparability of groups did not differ more than would be expected given…

  7. 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.

  8. 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.

  9. 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.

  10. Capabilities of long-baseline experiments in the presence of a sterile neutrino

    DOE PAGES

    Dutta, Debajyoti; Gandhi, Raj; Kayser, Boris; ...

    2016-11-21

    Assuming that there is a sterile neutrino, we ask what then is the ability of long-baseline experiments to i) establish that neutrino oscillation violates CP, ii) determine the three-neutrino mass ordering, and iii) determine which CP-violating phase or phases are the cause of any CP violation that may be observed. We find that the ability to establish CP violation and to determine the mass ordering could be very substantial. However, the effects of the sterile neutrino could be quite large, and it might prove very difficult to determine which phase is responsible for an observed CP violation. We explain whymore » a sterile neutrino changes the long-baseline sensitivities to CP violation and to the mass ordering in the ways that it does. We note that long-baseline experiments can probe the presence of sterile neutrinos in a way that is different from, and complementary to, the probes of short-baseline experiments. As a result, we explore the question of how large sterile-active mixing angles need to be before long-baseline experiments can detect their effects, or how small they need to be before the interpretation of these experiments can safely disregard the possible existence of sterile neutrinos.« less

  11. Capabilities of long-baseline experiments in the presence of a sterile neutrino

    SciTech Connect

    Dutta, Debajyoti; Gandhi, Raj; Kayser, Boris; Masud, Mehedi; Prakash, Suprabh

    2016-11-21

    Assuming that there is a sterile neutrino, we ask what then is the ability of long-baseline experiments to i) establish that neutrino oscillation violates CP, ii) determine the three-neutrino mass ordering, and iii) determine which CP-violating phase or phases are the cause of any CP violation that may be observed. We find that the ability to establish CP violation and to determine the mass ordering could be very substantial. However, the effects of the sterile neutrino could be quite large, and it might prove very difficult to determine which phase is responsible for an observed CP violation. We explain why a sterile neutrino changes the long-baseline sensitivities to CP violation and to the mass ordering in the ways that it does. We note that long-baseline experiments can probe the presence of sterile neutrinos in a way that is different from, and complementary to, the probes of short-baseline experiments. As a result, we explore the question of how large sterile-active mixing angles need to be before long-baseline experiments can detect their effects, or how small they need to be before the interpretation of these experiments can safely disregard the possible existence of sterile neutrinos.

  12. 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.

  13. 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.

  14. 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.

  15. Hydrodynamic instability experiments and simulations

    SciTech Connect

    Dimonte, G.; Schneider, M.; Frerking, C.E.

    1995-07-01

    Richtmyer-Meshkov experiments are conducted on the Nova laser with strong radiatively driven shocks (Mach > 20) in planar, two-fluid targets with Atwood number A < 0. Single mode interfacial perturbations are used to test linear theory and 3D random perturbations are used to study turbulent mix. Rayleigh-Taylor experiments are conducted on a new facility called the Linear Electric Motor (LEM) in which macroscopic fluids are accelerated electromagnetically with arbitrary acceleration profiles. The initial experiments are described. Hydrodynamic simulations in 2D are in reasonable agreement with the experiments, but these studies show that simulations in 3D with good radiation transport and equation of state are needed.

  16. Short-baseline electron neutrino oscillation length after the Troitsk experiment

    NASA Astrophysics Data System (ADS)

    Giunti, C.; Laveder, M.; Li, Y. F.; Long, H. W.

    2013-01-01

    We discuss the implications for short-baseline electron neutrino disappearance in the 3+1 mixing scheme of the recent Troitsk bounds on the mixing of a neutrino with mass between 2 and 100 eV. Considering the Troitsk data in combination with the results of short-baseline νe and ν¯e disappearance experiments, which include the reactor and Gallium anomalies, we derive a 2σ allowed range for the effective neutrino squared-mass difference between 0.85 and 43eV2. The upper bound implies that it is likely that oscillations in distance and/or energy can be observed in radioactive source experiments. It is also favorable for the ICARUS@CERN experiment, in which it is likely that oscillations are not washed out in the near detector. We discuss also the implications for neutrinoless double-β decay.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. Turbulent mix experiments and simulations

    SciTech Connect

    Dimonte, G.; Schneider, M.; Frerking, C.E.

    1995-08-01

    Hydrodynamic instabilities produce material mixing that can significantly degrade weapons performance. We investigate the Richtmyer-Meshkov (RM) and Rayleigh-Taylor (RT) instabilities in the turbulent regime in two experimental venues. RM experiments are conducted on the Nova laser with strong radiatively driven shocks (Mach > 20) in planar, two fluid targets. Interfacial perturbations are imposed with single sinusoidal modes to test linear theory and with three dimensional (3D) random modes to produce turbulent mix. RT experiments are conducted on a new facility, the Linear Electric Motor (LEM), in which macroscopic fluids are accelerated with arbitrary temporal profiles. This allows detailed diagnosis of the turbulence over a wide range of conditions. The Nova experiments study the high compression regime whereas the LEM experiments are incompressible. The results are compared to hydrodynamic simulations with the arbitrary Lagrangian-Eulerian code (CALE). The goal is to develop and test engineering models of mix.

  2. 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.

  3. 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

  4. 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.

  5. 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.

  6. Baseline Optimization for the Measurement of CP Violation, Mass Hierarchy, and $\\theta_{23}$ Octant in a Long-Baseline Neutrino Oscillation Experiment

    SciTech Connect

    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.

    2015-03-19

    Next-generation long-baseline electron neutrino appearance experiments will seek to discover CP 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.

  7. 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.

  8. 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.

  9. Comet Simulation Experiments at JPL

    NASA Astrophysics Data System (ADS)

    Green, J. R.; Bruesch, L. S.; Oakes, R.; Pinkham, B.; Folsom, C. L.

    1999-12-01

    recorded on video tape. A mechanical penetrator-scratcher measures penetrability and disturbs the surface for assessment of surface changes. At the end of the experiment, the sample is removed and core samples are taken for tests of compression strength, penetrability, porosity, density, and thin section analysis. Methods allowing detailed microscopic examination of the samples are under development. A freezing microtome for cutting thin sections of the sample and a freezing stage on a microscope are to be used for examination of the pore and grain structure of the icy mixtures. With all elements in place for the laboratory simulation of cometary materials, we are now performing our first experiments and plan to report our preliminary results.

  10. 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

  11. 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.

  12. Initial results from the CHOOZ long baseline reactor neutrino oscillation experiment

    NASA Astrophysics Data System (ADS)

    Apollonio, M.; Baldini, A.; Bemporad, C.; Caffau, E.; Cei, F.; Déclais, Y.; de Kerret, H.; Dieterle, B.; Etenko, A.; George, J.; Giannini, G.; Grassi, M.; Kozlov, Y.; Kropp, W.; Kryn, D.; Laiman, M.; Lane, C. E.; Lefièvre, B.; Machulin, I.; Martemyanov, A.; Martemyanov, V.; Mikaelyan, L.; Nicolò, D.; Obolensky, M.; Pazzi, R.; Pieri, G.; Price, L.; Riley, S.; Reeder, R.; Sabelnikov, A.; Santin, G.; Skorokhvatov, M.; Sobel, H.; Steele, J.; Steinberg, R.; Sukhotin, S.; Tomshaw, S.; Veron, D.; Vyrodov, V.

    1998-02-01

    Initial results are presented from CHOOZ, a long-baseline reactor-neutrino vacuum-oscillation experiment. The data reported here were taken during the period March to October 1997, when the two reactors ran at combined power levels varying from zero to values approaching their full rated power of 8.5 (thermal). Electron antineutrinos from the reactors were detected by a liquid scintillation calorimeter located at a distance of about 1. The detector was constructed in a tunnel protected from cosmic rays by a 300 rock overburden. This massive shielding strongly reduced potentially troublesome backgrounds due to cosmic-ray muons, leading to a background rate of about one event per day, more than an order of magnitude smaller than the observed neutrino signal. From the statistical agreement between detected and expected neutrino event rates, we find (at 90% confidence level) no evidence for neutrino oscillations in the disappearance mode for the parameter region given approximately by for maximum mixing and for large .

  13. 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.

  14. Comparison of Baseline Wander Removal Techniques considering the Preservation of ST Changes in the Ischemic ECG: A Simulation Study

    PubMed Central

    Pilia, Nicolas; Schulze, Walther H. W.; Dössel, Olaf

    2017-01-01

    The most important ECG marker for the diagnosis of ischemia or infarction is a change in the ST segment. Baseline wander is a typical artifact that corrupts the recorded ECG and can hinder the correct diagnosis of such diseases. For the purpose of finding the best suited filter for the removal of baseline wander, the ground truth about the ST change prior to the corrupting artifact and the subsequent filtering process is needed. In order to create the desired reference, we used a large simulation study that allowed us to represent the ischemic heart at a multiscale level from the cardiac myocyte to the surface ECG. We also created a realistic model of baseline wander to evaluate five filtering techniques commonly used in literature. In the simulation study, we included a total of 5.5 million signals coming from 765 electrophysiological setups. We found that the best performing method was the wavelet-based baseline cancellation. However, for medical applications, the Butterworth high-pass filter is the better choice because it is computationally cheap and almost as accurate. Even though all methods modify the ST segment up to some extent, they were all proved to be better than leaving baseline wander unfiltered. PMID:28373893

  15. 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,…

  16. 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.

  17. 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.

  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. 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…

  20. 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.

  1. Diffusion Processes: Experiment, Theory, Simulations

    NASA Astrophysics Data System (ADS)

    Pekalski, Andrzej

    The articles in this book reflect the omnipresence of diffusion processes in the natural sciences. They describe experimental results as well as theoretical models and computer simulations, and address a wide readership including graduate students. The problems treated stem from physics, astronomy, physical chemistry, biology, and medicine. The papers are presented in a tutorial style and reflect the present-day trends in the field.

  2. 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.

  3. 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.

  4. Simulation of GRETINA Lifetime Experiment

    NASA Astrophysics Data System (ADS)

    Littley, Cody; Iwasaki, Hironori; Lemasson, Antoine

    2011-10-01

    In order to understand properties of exotic atomic nuclei, the research group has developed a method to measure the rate of decay of excited states in certain unstable isotopes, for example 66Fe. By measuring the Doppler shift of gamma rays with a so-called plunger device it is possible to deduce with great accuracy the excited-state lifetime. This technique, which is called the Recoil Distance Doppler-shift Method, has precision on the order of one pico second. I will present the development a simulation software package which will help the research team to quantize and to analyze the data from experimental runs. This software is based upon existing software which was used for simulations of the SeGA project. It has been modified to support the GRETINA detector, which is used in the experimental setup for the lifetime measurements. The software makes use GEANT and ROOT toolkits, which are essential for the calculations of the interactions of particles with the detector and the recording of that data.

  5. 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.

  6. 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.

  7. 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.

  8. An Introductory Scattering Experiment by Simulation

    ERIC Educational Resources Information Center

    Merrill, John R.; Morrow, Richard A.

    1970-01-01

    Describes an introductory physics experiment concerned with scattering particles off various force centers. The experiment uses simulation techniques and a computer. The scattering is classical, and the student examines plots of computed particle trajectories. The results illustrate the concepts of differential corss-section, total cross-section,…

  9. A Program for Simulated Thermodynamic Experiments.

    ERIC Educational Resources Information Center

    Olds, Dan W.

    A time-sharing FORTRAN program is described. It was created to allow a student to design and perform classical thermodynamic experiments on three models of a working substance. One goal was to develop a simulation which gave the student maximum freedom and responsibility in the design of the experiment and provided only the primary experimental…

  10. Long-Baseline Neutrino Facility (LBNF) and Deep Underground Neutrino Experiment (DUNE): Conceptual Design Report. Volume 3: Long-Baseline Neutrino Facility for DUNE

    SciTech Connect

    Strait, James; McCluskey, Elaine; Lundin, Tracy; Willhite, Joshua; Hamernik, Thomas; Papadimitriou, Vaia; Marchionni, Alberto; Kim, Min Jeong; Nessi, Marzio; Montanari, David; Heavey, Anne

    2016-01-21

    This volume of the LBNF/DUNE Conceptual Design Report covers the Long-Baseline Neutrino Facility for DUNE and describes the LBNF Project, which includes design and construction of the beamline at Fermilab, the conventional facilities at both Fermilab and SURF, and the cryostat and cryogenics infrastructure required for the DUNE far detector.

  11. Baseline neoclassical scaling law on H-mode pedestal width from XGC0 kinetic simulation

    NASA Astrophysics Data System (ADS)

    Park, Gunyoung; Chang, C. S.; Ku, S.

    2009-11-01

    In the H-mode pedestal before the ELM onset, nonlocal neoclassical self-organization is an important physical effect, to set the baseline pedestal width scaling law. Deviation from the neoclassical scaling will define the anomalous scaling. The neoclassical self-organization includes effects from the self-consistent radial electric field shear, strong magnetic field shear, ion-orbit loss across the last closed magnetic surface, finite ion banana width, particle source from neutral ionization, heat flux from the core plasma, and collisional transport. XGC0 code is used to perform an inter-machine study of the neoclassical pedestal scaling law between two representative devices DIII-D (low-B, low collisionality) and C- Mod (high-B, high collisionality). Anomalous scaling component in the experimental pedestal width data will be separated out from the neoclassical component. Prediction for ITER pedestal will be attempted based upon the combined neoclassical (theoretical) and anomalous (empirical) scaling laws obtained in this study. This ion-electron study indicates that the neoclassical pedestal width is broader than the previous ion only study results, closer to experimental pedestal width.

  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. 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).

  14. 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.

  15. 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

  16. Experiments with the KITE attitude control simulator

    NASA Technical Reports Server (NTRS)

    Powell, J. David; Kline-Schoder, Robert

    1989-01-01

    Simulation experiments are conducted to test an attitude control technique for tethered satellites using the tether tension force to generate control torques by moving the tether attach point relative to the satellite center of mass. A scaled, one-dimensional, air-bearing supported laboratory simulation of the Kinetic Isolation Tether Experiment shows that the attitude of the simulator can be regulated to within 0.75 arcsec with a bandwidth of about 0.1 Hz. The control design includes a state estimator to calculate the vehicle mass center and to calculate the effect of the stepper motor dynamics on the state estimate. Results are presented from closed-loop attitude control experiments to verify the attitude control technique.

  17. Simulation of MTF experiments at General Fusion

    NASA Astrophysics Data System (ADS)

    Reynolds, Meritt; Froese, Aaron; Barsky, Sandra; Devietien, Peter; Toth, Gabor; Brennan, Dylan; Hooper, Bick

    2016-10-01

    General Fusion (GF) aims to develop a magnetized target fusion (MTF) power plant based on compression of magnetically-confined plasma by liquid metal. GF is testing this compression concept by collapsing solid aluminum liners onto spheromak or tokamak plasmas. To simulate the evolution of the compressing plasma in these experiments, we integrated a moving-mesh method into a finite-volume MHD code (VAC). The single-fluid model includes temperature-dependent resistivity and anisotropic heat transport. The trajectory of the liner is based on experiments and LS-DYNA simulations. During compression the geometry remains axially symmetric, but the MHD simulation is fully 3D to capture ideal and resistive plasma instabilities. We compare simulation to experiment through the primary diagnostic of Mirnov probes embedded in the inner coaxial surface against which the magnetic flux and plasma are compressed by the imploding liner. The MHD simulation reproduces the appearance of n=1 mode activity observed in experiments performed in negative D-shape geometry (MRT and PROSPECTOR machines). The same code predicts more favorable compression in spherical tokamak geometry, having positive D-shape (SPECTOR machine).

  18. 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.

  19. The NOvA Timing System: A system for synchronizing a long baseline neutrino experiment

    NASA Astrophysics Data System (ADS)

    Norman, A.; Kwarciany, R.; Deuerling, G.; Wilcer, N.

    2012-12-01

    The NOvA experiment is designed to measure key parameters in neutrino physics related to the neutrino mass hierarchy and the asymmetry between matter and anti-matter. To make these measurements the NOvA experiment must correlate the extraction of beam to the NuMI target with individual hits in both a near detector and a far detector located 810 km from Fermilab. Precisely correlating hits across these detectors and reconstructing particle trajectories require that all of the readout electronics be precisely synchronized to an absolute wall time with a channel to channel variation less than 15.6 ns. The NOvA Timing Distribution System accomplishes this through an integration of commercial GPS receiver technology and custom electronics. This paper describes the timing system, its component hardware and the synchronization method that is employed by it.

  20. Search for Sterile Neutrinos with the MINOS Long-Baseline Experiment

    SciTech Connect

    Timmons, Ashley Michael

    2016-01-01

    This thesis will present a search for sterile neutrinos using data taken with the MINOS experiment between 2005 and 2012. MINOS is a two-detector on-axis experiment based at Fermilab. The NuMI neutrino beam encounters the MINOS Near Detector 1km downstream of the neutrino-production target before traveling a further 734km through the Earth's crust, to reach the Far Detector located at the Soudan Underground Laboratory in Northern Minnesota. By searching for oscillations driven by a large mass splitting, MINOS is sensitive to the existence of sterile neutrinos through looking for any energy-dependent perturbations using a charged-current sample, as well as looking at any relative deficit in neutral current events between the Far and Near Detectors. This thesis will discuss the novel analysis that enabled a search for sterile neutrinos covering five orders of magnitude in the mass splitting and setting a limit in previously unexplored regions of the parameter space $\\left\\{\\Delta m^{2}_{41},\\sin^2\\theta_{24}\\right\\}$, where a 3+1-flavour phenomenological model was used to extract parameter limits. The results presented in this thesis are sensitive to the sterile neutrino parameter space suggested by the LSND and MiniBooNE experiments.

  1. 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…

  2. Monte Carlo Simulation of Counting Experiments.

    ERIC Educational Resources Information Center

    Ogden, Philip M.

    A computer program to perform a Monte Carlo simulation of counting experiments was written. The program was based on a mathematical derivation which started with counts in a time interval. The time interval was subdivided to form a binomial distribution with no two counts in the same subinterval. Then the number of subintervals was extended to…

  3. Introduction to Observing System Simulation Experiments (OSSEs)

    NASA Technical Reports Server (NTRS)

    Prive, Nikki C.

    2014-01-01

    This presentation gives a brief overview of Observing System Simulation Experiments (OSSEs), including what OSSEs are, and how and why they are performed. The intent is to educate the audience in light of the OSSE-related sections of the Forecast Improvement Act (H.R. 2413).

  4. 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.

  5. Polyurethane Foam Impact Experiments and Simulations

    SciTech Connect

    Chhabildas, L.C.; Kipp, M.E.; Reinhart, W.D.; Wong, M.K.

    1999-06-17

    Uniaxial strain impact experiments have been performed to obtain shock compression and release response of a 0.22 g/cm{sup 3} polyurethane foam in a configuration where the foam impacts a thin target witness plate. Wave profiles from a suite of ten experiments have been obtained, where shock amplitudes range from 40 to 500 MPa. A traditional p-{alpha} porous material model generally captures the material response. A fully three-dimensional explicit representation of the heterogeneous foam structure modeled with numerical simulations recovers some of the high frequency aspects of the particle velocity records.

  6. 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.

  7. Simulations and Experiments in Astronomy and Physics

    NASA Astrophysics Data System (ADS)

    Maloney, F. P.; Maurone, P. A.; Dewarf, L. E.

    1998-12-01

    There are new approaches to teaching astronomy and physics in the laboratory setting, involving the use of computers as tools to simulate events and concepts which can be illuminated in no other reasonable way. With the computer, it is possible to travel back in time to replicate the sky as Galileo saw it. Astronomical phenomena which reveal themselves only after centuries of real time may be compressed in the computer to a simulation of several minutes. Observations simulated on the computer do not suffer from the vagaries of weather, fixed time or geographic position, or non-repeatability. In physics, the computer allows us to secure data for experiments which, by their nature, may not be amenable to human interaction. These could include experiments with very fast or very slow timescales, large number of data samples, complex or tedious manipulation of the data which hides the fundamental nature of the experiment, or data sampling which would need a specialized probe, such as for acid rain. This innovation has become possible only recently, due to the availability and affordability of sophisticated computer hardware and software. We have developed a laboratory experience for non-scientists who need an introductory course in astronomy or physics. Our approach makes extensive use of computers in this laboratory. Using commercially available software, the students use the computer as a time machine and a space craft to explore and rediscover fundamental science. The physics experiments are classical in nature, and the computer acts as a data collector and presenter, freeing the student from the tedium of repetitive data gathering and replotting. In this way, the student is encouraged to explore, to try new things, to refine the measurements, and to discover the principles underlying the observed phenomena.

  8. 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

  9. Direct Simulation of a Solidification Benchmark Experiment

    NASA Astrophysics Data System (ADS)

    Carozzani, Tommy; Gandin, Charles-André; Digonnet, Hugues; Bellet, Michel; Zaidat, Kader; Fautrelle, Yves

    2013-02-01

    A solidification benchmark experiment is simulated using a three-dimensional cellular automaton—finite element solidification model. The experiment consists of a rectangular cavity containing a Sn-3 wt pct Pb alloy. The alloy is first melted and then solidified in the cavity. A dense array of thermocouples permits monitoring of temperatures in the cavity and in the heat exchangers surrounding the cavity. After solidification, the grain structure is revealed by metallography. X-ray radiography and inductively coupled plasma spectrometry are also conducted to access a distribution map of Pb, or macrosegregation map. The solidification model consists of solutions for heat, solute mass, and momentum conservations using the finite element method. It is coupled with a description of the development of grain structure using the cellular automaton method. A careful and direct comparison with experimental results is possible thanks to boundary conditions deduced from the temperature measurements, as well as a careful choice of the values of the material properties for simulation. Results show that the temperature maps and the macrosegregation map can only be approached with a three-dimensional simulation that includes the description of the grain structure.

  10. 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.

  11. 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.

  12. Combined analysis of short-baseline neutrino experiments in the (3+1) and (3+2) sterile neutrino oscillation hypotheses

    SciTech Connect

    Sorel, M.; Conrad, J.M.; Shaevitz, M.H.

    2004-10-01

    We investigate adding two sterile neutrinos to resolve the apparent tension existing between short-baseline neutrino oscillation results and CPT-conserving, four-neutrino oscillation models. For both (3+1) and (3+2) models, the level of statistical compatibility between the combined dataset from the null short-baseline experiments Bugey, CHOOZ, CCFR84, CDHS, KARMEN, and NOMAD, on the one hand; and the LSND dataset, on the other, is computed. A combined analysis of all seven short-baseline experiments, including LSND, is also performed, to obtain the favored regions in neutrino mass and mixing parameter space for both models. Finally, four statistical tests to compare the (3+1) and the (3+2) hypotheses are discussed. All tests show that (3+2) models fit the existing short-baseline data significantly better than (3+1) models.

  13. Data Simulation for 21 cm Cosmology Experiments

    NASA Astrophysics Data System (ADS)

    Pober, Jonathan

    2017-01-01

    21 cm cosmologists seek a measurement of the hyperfine line of neutral hydrogen from very high redshifts. While this signal has the potential to provide an unprecedented view into the early universe, it is also buried under exceedingly bright foreground emission. Over the last several years, 21 cm cosmology research has led to an improved understanding of how low frequency radio interferometers will affect the separation of cosmological signal from foregrounds. This talk will describe new efforts to incorporate this understanding into simulations of the most realistic data sets for the Precision Array for Probing the Epoch of Reionization (PAPER), the Murchison Widefield Array (MWA), and the Hydrogen Epoch of Reionization Array (HERA). These high fidelity simulations are essential for robust algorithm design and validation of early results from these experiments.

  14. 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.

  15. 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.

  16. Simulation studies for the PANDA experiment

    SciTech Connect

    Kopf, B.

    2005-10-26

    One main component of the planned Facility for Antiproton and Ion Research (FAIR) is the High Energy Storage Ring (HESR) at GSI, Darmstadt, which will provide cooled antiprotons with momenta between 1.5 and 15 GeV/c. The PANDA experiment will investigate p-barannihilations with internal hydrogen and nuclear targets. Due to the planned extensive physics program a multipurpose detector with nearly complete solid angle coverage, proper particle identification over a large momentum range, and high resolution calorimetry for neutral particles is required. For the optimization of the detector design simulation studies of several benchmark channels are in progress which are covering the most relevant physics topics. Some important simulation results are discussed here.

  17. 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.

  18. 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.

  19. Impact of lepton flavor universality violation on CP-violation sensitivity of long-baseline neutrino oscillation experiments

    NASA Astrophysics Data System (ADS)

    Soumya, C.; Mohanta, R.

    2017-01-01

    The observation of neutrino oscillation as well as the recent experimental results on lepton flavor universality (LFU) violation in B meson decays are indications of new physics beyond the standard model. Many theoretical models, which are introduced in the literature as an extension of SM to explain these observed deviations in LFU, lead to a new kind of interactions, the so-called non-standard interaction (NSI) between the elementary particles. In this paper, we consider a model with an additional Z' boson (which is quite successful in explaining the observed LFU anomalies) and analyze its effect in the lepton flavor violating (LFV) B_d→ τ ^± e^∓ decay modes. From the present upper bound of the B_d→ τ ^± e^∓ branching ratio, we obtain the constraints on the new physics parameters, which are related to the corresponding NSI parameters in the neutrino sector by SU(2)_L symmetry. These new parameters are expected to have potential implications in the neutrino oscillation studies and in this work we investigate the possibility of observing the effects of these interactions in the currently running and upcoming long-baseline experiments, i.e., NOν A and DUNE, respectively.

  20. Developing novel techniques for readout, calibration and event selection in the NOvA long-baseline neutrino experiment

    SciTech Connect

    Patterson, Ryan; Backhouse, Christopher; Bays, Kirk; Lozier, Joseph; Pershey, Daniel

    2016-10-01

    The NOvA long-baseline neutrino experiment uses a fine-grained, low-Z, fully active detector that offers unprecedented electron neutrino identification capabilities for a detector of its scale. In this award’s proposal, the PI outlined the development and implementation of novel techniques for channel readout, detector calibration, and event reconstruction that make full use of the strengths of the NOvA detector technology. In particular, this included designing custom event reconstruction algorithms that utilize the rich information available in the substructure of hadronic and electromagnetic showers. Exploiting this information provides not only substantial improvement in background rejection for the electron neutrino search but also better shower energy resolution (improving the precision on measured oscillation parameters) and a high-energy electromagnetic calibration source (through neutral pion events). The PI further proposed developing and deploying a new electronics readout scheme compatible with the existing hardware that can reduce near detector event pile-up and can offer powerful timing information to the reconstruction, allowing for cosmic ray muon tagging via track direction determination, among other things. In conjunction with the above, the PI proposed leading the calibration of the NOvA detectors, including characterizing individual electronics channels, correcting for spatial variations across the detector, and establishing absolute event energy scales. All three of these lines of effort have been successfully completed, feeding directly into the NOvA’s recent exciting neutrino oscillation results. The techniques developed under this award are detailed in this final technical report.

  1. 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.

  2. [Simulation in medicine: first experiences under hemodialysis].

    PubMed

    Duranti, Ennio; Calzeroni, Gino; Venneri, Francesco; Marziali, Mauro

    2013-01-01

    Education and practical training in medicine is neglected and pass directly from theory to do on the field, while also each task requires the acquisition of health behaviors that are aware and accountable to the outreach. In hemodialysis is necessary to create synergies and partnerships between different cooperating figures. Addressing organizational and legal protection of the professionals (Clinical Risk). Acquiring operational capabilities of team work. Managing the team roles and functions.It is necessary then to acquire a modern methodology where the simulation represents the main tool, "the mistake" need to "learn" and the acquisition of "awareness" about event handling (in this case on Hemodialysis), in the context of clinical scenarios absolutely realistic.The methodology is based on simulated tasks using past experience as a business tool and innovative research. Debriefing and discussion with those involved and finally debrief collegiate looking for active/latent errors and use of international guidelines. Use of indicators to measure and review of performance during the various events and proactively promoting the reduction of the error.Among the types of participants was clear the minor presence of doctors of hemodialysis, probably for the wrong feeling of being checked and then judged in carrying out of actions made complex by urgency. In addition participating physicians have all stressed the usefulness of simulations of unusual events within the Hemodialysis treatment, but that if not solved can lead to death of the patient.Simulation under hemodialysis, although its first steps, appears to be an effective methodology able to stimulate self-criticism of the operators, but still with hesitations and fears above all by the nephrologists timorous of being judged more on technical skills than on organizational skills and leadership.

  3. 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.

  4. Simulation of a complete inelastic neutron scattering experiment

    NASA Astrophysics Data System (ADS)

    Edwards, H.; Lefmann, K.; Lake, B.; Nielsen, K.; Skaarup, P.

    A simulation of an inelastic neutron scattering experiment on the high-temperature superconductor La2-xSrxCuO4 is presented. The complete experiment, including sample, is simulated using an interface between the experiment control program and the simulation software package (McStas) and is compared with the experimental data. Simulating the entire experiment is an attractive alternative to the usual method of convoluting the model cross section with the resolution function, especially if the resolution function is nontrivial.

  5. Long-Baseline Neutrino Facility (LBNF) and Deep Underground Neutrino Experiment (DUNE): Conceptual Design Report. Volume 1: The LBNF and DUNE Projects

    SciTech Connect

    Acciarri, R.

    2016-01-22

    This document presents the Conceptual Design Report (CDR) put forward by an international neutrino community to pursue the Deep Underground Neutrino Experiment at the Long-Baseline Neutrino Facility (LBNF/DUNE), a groundbreaking science experiment for long-baseline neutrino oscillation studies and for neutrino astrophysics and nucleon decay searches. The DUNE far detector will be a very large modular liquid argon time-projection chamber (LArTPC) located deep underground, coupled to the LBNF multi-megawatt wide-band neutrino beam. DUNE will also have a high-resolution and high-precision near detector.

  6. Simulation and Reconstruction for the OLIVIA Experiment

    NASA Astrophysics Data System (ADS)

    Borucki, Timothy; Olivia Collaboration

    2017-01-01

    OLIVIA is an experiment that will provide a sensitive test of the weak interaction. The idea is to analyze Li-8 beta decay, followed by the double-alpha decay of the Be-8 daughter, using a gas-based Time Projection Chamber (TPC). Specifically, precision kinematic measurements of the 2 MeV alphas allow us to probe the V-A nature of the weak interaction. Alphas emitted in the TPC produce trails of ionization, which are drifted down through the detector to an amplification plane. The amplified track signals are then photographed and read out in time to provide a three-dimensional picture of the Li-8 decay event. Along with presenting the status and outlook for the OLIVIA project, I will discuss my work on simulating and reconstructing double-alpha waveforms from the TPC's amplification plane. This work is essential for achieving excellent alpha energy resolution, which will ultimately set OLIVIA's sensitivity to new physics.

  7. Braiding DNA: experiments, simulations, and models.

    PubMed

    Charvin, G; Vologodskii, A; Bensimon, D; Croquette, V

    2005-06-01

    DNA encounters topological problems in vivo because of its extended double-helical structure. As a consequence, the semiconservative mechanism of DNA replication leads to the formation of DNA braids or catenanes, which have to be removed for the completion of cell division. To get a better understanding of these structures, we have studied the elastic behavior of two braided nicked DNA molecules using a magnetic trap apparatus. The experimental data let us identify and characterize three regimes of braiding: a slightly twisted regime before the formation of the first crossing, followed by genuine braids which, at large braiding number, buckle to form plectonemes. Two different approaches support and quantify this characterization of the data. First, Monte Carlo (MC) simulations of braided DNAs yield a full description of the molecules' behavior and their buckling transition. Second, modeling the braids as a twisted swing provides a good approximation of the elastic response of the molecules as they are intertwined. Comparisons of the experiments and the MC simulations with this analytical model allow for a measurement of the diameter of the braids and its dependence upon entropic and electrostatic repulsive interactions. The MC simulations allow for an estimate of the effective torsional constant of the braids (at a stretching force F = 2 pN): C(b) approximately 48 nm (as compared with C approximately 100 nm for a single unnicked DNA). Finally, at low salt concentrations and for sufficiently large number of braids, the diameter of the braided molecules is observed to collapse to that of double-stranded DNA. We suggest that this collapse is due to the partial melting and fraying of the two nicked molecules and the subsequent right- or left-handed intertwining of the stretched single strands.

  8. NDCX-II target experiments and simulations

    DOE PAGES

    Barnard, J. J.; More, R. M.; Terry, M.; ...

    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

  9. 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.

  10. 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.

  11. 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.

  12. Impact of an Advanced Cardiac Life Support Simulation Laboratory Experience on Pharmacy Student Confidence and Knowledge

    PubMed Central

    Mohorn, Phillip L.; Haney, Jason S.; Phillips, Cynthia M.; Lu, Z. Kevin; Clark, Kimberly; Corboy, Alex; Ragucci, Kelly R.

    2016-01-01

    Objective. To assess the impact of an advanced cardiac life support (ACLS) simulation on pharmacy student confidence and knowledge. Design. Third-year pharmacy students participated in a simulation experience that consisted of team roles training, high-fidelity ACLS simulations, and debriefing. Students completed a pre/postsimulation confidence and knowledge assessment. Assessment. Overall, student knowledge assessment scores and student confidence scores improved significantly. Student confidence and knowledge changes from baseline were not significantly correlated. Conversely, a significant, weak positive correlation between presimulation studying and both presimulation confidence and presimulation knowledge was discovered. Conclusions. Overall, student confidence and knowledge assessment scores in ACLS significantly improved from baseline; however, student confidence and knowledge were not significantly correlated. PMID:27899836

  13. Impact of an Advanced Cardiac Life Support Simulation Laboratory Experience on Pharmacy Student Confidence and Knowledge.

    PubMed

    Maxwell, Whitney D; Mohorn, Phillip L; Haney, Jason S; Phillips, Cynthia M; Lu, Z Kevin; Clark, Kimberly; Corboy, Alex; Ragucci, Kelly R

    2016-10-25

    Objective. To assess the impact of an advanced cardiac life support (ACLS) simulation on pharmacy student confidence and knowledge. Design. Third-year pharmacy students participated in a simulation experience that consisted of team roles training, high-fidelity ACLS simulations, and debriefing. Students completed a pre/postsimulation confidence and knowledge assessment. Assessment. Overall, student knowledge assessment scores and student confidence scores improved significantly. Student confidence and knowledge changes from baseline were not significantly correlated. Conversely, a significant, weak positive correlation between presimulation studying and both presimulation confidence and presimulation knowledge was discovered. Conclusions. Overall, student confidence and knowledge assessment scores in ACLS significantly improved from baseline; however, student confidence and knowledge were not significantly correlated.

  14. 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.

  15. 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.

  16. 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

  17. Simulating Astrophysical Jets in Laboratory Experiments

    NASA Astrophysics Data System (ADS)

    Bellan, Paul

    2004-11-01

    A laboratory plasma configuration based on spheromak [1] magnetic fusion plasma physics technology is used to simulate many important features of magnetically driven astrophysical jets. The experimental sequence starts with a quasi-static seed poloidal magnetic field that links a central disk electrode to a co-planar bounding annular electrode; this arrangement provides a topology analogous to the poloidal magnetic field of a star linking a surrounding accretion disk. After puffing neutral gas from nozzles mounted on the electrodes, plasma is created via application of a large emf between the central disk and the bounding annular electrode. The emf then drives a large poloidal electric current flowing from the central disk electrode (star) to the annulus (accretion disk) along the bias poloidal magnetic field. This electric current produces large magnetohydrodynamic forces which result in dynamics analogous to the dynamics of an astrophysical jet. In particular, the laboratory "astrophysical jet" is observed [2,3] to evolve through a distinct, reproducible sequence consisting of jet formation, collimation, kink instability, and for appropriate parameters, detachment into an unbounded, expanding spheromak-like plasmoid. These observations and related observations on a solar prominence simulation experiment [4] have motivated an analytic model [5] for the collimation physics whereby stagnation of convected, frozen-in toroidal magnetic flux amplifies the toroidal magnetic flux density and then, since the toroidal magnetic field (i.e., toroidal flux density) provides the pinch force, the pinch force is increased, collimating the jet. The following talk (You, Bellan, Yun) will present detailed measurements of the jet formation, acceleration, and collimation process. [1] P. M. Bellan, Spheromaks (Imperial College Press, London, 2000). [2] S. C. Hsu and P. M. Bellan, Mon. Not. R. Astron. Soc. 334, 257 (2002). [3] S. C. Hsu and P. M. Bellan, Phys. Rev. Letters 90, article

  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. Bias, precision and statistical power of analysis of covariance in the analysis of randomized trials with baseline imbalance: a simulation study

    PubMed Central

    2014-01-01

    Background Analysis of variance (ANOVA), change-score analysis (CSA) and analysis of covariance (ANCOVA) respond differently to baseline imbalance in randomized controlled trials. However, no empirical studies appear to have quantified the differential bias and precision of estimates derived from these methods of analysis, and their relative statistical power, in relation to combinations of levels of key trial characteristics. This simulation study therefore examined the relative bias, precision and statistical power of these three analyses using simulated trial data. Methods 126 hypothetical trial scenarios were evaluated (126 000 datasets), each with continuous data simulated by using a combination of levels of: treatment effect; pretest-posttest correlation; direction and magnitude of baseline imbalance. The bias, precision and power of each method of analysis were calculated for each scenario. Results Compared to the unbiased estimates produced by ANCOVA, both ANOVA and CSA are subject to bias, in relation to pretest-posttest correlation and the direction of baseline imbalance. Additionally, ANOVA and CSA are less precise than ANCOVA, especially when pretest-posttest correlation ≥ 0.3. When groups are balanced at baseline, ANCOVA is at least as powerful as the other analyses. Apparently greater power of ANOVA and CSA at certain imbalances is achieved in respect of a biased treatment effect. Conclusions Across a range of correlations between pre- and post-treatment scores and at varying levels and direction of baseline imbalance, ANCOVA remains the optimum statistical method for the analysis of continuous outcomes in RCTs, in terms of bias, precision and statistical power. PMID:24712304

  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. Liquid crystal interfaces: Experiments, simulations and biosensors

    NASA Astrophysics Data System (ADS)

    Popov, Piotr

    Interfacial phenomena are ubiquitous and extremely important in various aspects of biological and industrial processes. For example, many liquid crystal applications start by alignment with a surface. The underlying mechanisms of the molecular organization of liquid crystals at an interface are still under intensive study and continue to be important to the display industry in order to develop better and/or new display technology. My dissertation research has been devoted to studying how complex liquid crystals can be guided to organize at an interface, and to using my findings to develop practical applications. Specifically, I have been working on developing biosensors using liquid-crystal/surfactant/lipid/protein interactions as well as the alignment of low-symmetry liquid crystals for potential new display and optomechanical applications. The biotechnology industry needs better ways of sensing biomaterials and identifying various nanoscale events at biological interfaces and in aqueous solutions. Sensors in which the recognition material is a liquid crystal naturally connects the existing knowledge and experience of the display and biotechnology industries together with surface and soft matter sciences. This dissertation thus mainly focuses on the delicate phenomena that happen at liquid interfaces. In the introduction, I start by defining the interface and discuss its structure and the relevant interfacial forces. I then introduce the general characteristics of biosensors and, in particular, describe the design of biosensors that employ liquid crystal/aqueous solution interfaces. I further describe the basic properties of liquid crystal materials that are relevant for liquid crystal-based biosensing applications. In CHAPTER 2, I describe the simulation methods and experimental techniques used in this dissertation. In CHAPTER 3 and CHAPTER 4, I present my computer simulation work. CHAPTER 3 presents insight of how liquid crystal molecules are aligned by

  3. Observing System Simulation Experiments for Hurricanes

    NASA Astrophysics Data System (ADS)

    Atlas, R. M.; Hoffman, R. N.; Bucci, L. R.; Annane, B.; Murillo, S.

    2015-12-01

    Observing System Simulation Experiments (OSSEs), when done correctly, provide an effective means to evaluate the potential impact of a proposed observing system, as well as to determine tradeoffs in their design, and to evaluate data assimilation methodology. Great care must be taken to ensure the realism of the OSSEs and in the interpretation of OSSE results. While early OSSEs focused on large-scale numerical weather prediction, more recent OSSEs have included evaluation of the impact of proposed observing systems on smaller-scale phenomena. These have included global OSSEs to evaluate impact on hurricane track forecasting and regional OSSEs aimed at evaluating both track and intensity prediction. Two global OSSEs conducted using the fvGCM nature runs showed a substantial impact of space-based lidar wind profiles on hurricane track predictions. Current OSSEs are using multiple nature runs in which the WRF model, at very high resolution, is embedded within a global T511 nature run that had been generated by ECMWF. These OSSEs are evaluating the potential impact of new (proposed) observing systems on hurricane track and intensity prediction and trade-offs in the design and configuration of these observing systems They are also being used to optimize sampling strategies for current and future airborne and spaceborne observing systems and to evaluate and improve data assimilation and vortex initialization methodology for hurricane prediction. Results from recent OSSEs show the relative impact of alternative lidar technologies and the relative impact of global and regional assimilation on hurricane track and intensity prediction. OSSEs are currently underway to evaluate advanced concepts for hyperspectral infrared (IR) sounding from both polar and geostationary orbit, as well as to evaluate a variety of aspects of hurricane predictability.

  4. Development of Very Long Baseline Interferometry (VLBI) techniques in New Zealand: Array simulation, image synthesis and analysis

    NASA Astrophysics Data System (ADS)

    Weston, S. D.

    2008-04-01

    This thesis presents the design and development of a process to model Very Long Base Line Interferometry (VLBI) aperture synthesis antenna arrays. In line with the Auckland University of Technology (AUT) Institute for Radiophysics and Space Research (IRSR) aims to develop the knowledge, skills and experience within New Zealand, extensive use of existing radio astronomical software has been incorporated into the process namely AIPS (Astronomical Imaging Processing System), MIRIAD (a radio interferometry data reduction package) and DIFMAP (a program for synthesis imaging of visibility data from interferometer arrays of radio telescopes). This process has been used to model various antenna array configurations for two proposed New Zealand sites for antenna in a VLBI array configuration with existing Australian facilities and a passable antenna at Scott Base in Antarctica; and the results are presented in an attempt to demonstrate the improvement to be gained by joint trans-Tasman VLBI observation. It is hoped these results and process will assist the planning and placement of proposed New Zealand radio telescopes for cooperation with groups such as the Australian Long Baseline Array (LBA), others in the Pacific Rim and possibly globally; also potential future involvement of New Zealand with the SKA. The developed process has also been used to model a phased building schedule for the SKA in Australia and the addition of two antennas in New Zealand. This has been presented to the wider astronomical community via the Royal Astronomical Society of New Zealand Journal, and is summarized in this thesis with some additional material. A new measure of quality ("figure of merit") for comparing the original model image and final CLEAN images by utilizing normalized 2-D cross correlation is evaluated as an alternative to the existing subjective visual operator image comparison undertaken to date by other groups. This new unit of measure is then used ! in the presentation of the

  5. 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.

  6. Three-dimensional MHD simulation of the Caltech plasma jet experiment: first results

    SciTech Connect

    Zhai, Xiang; Bellan, Paul M.; Li, Hui; Li, Shengtai E-mail: pbellan@caltech.edu E-mail: sli@lanl.gov

    2014-08-10

    Magnetic fields are believed to play an essential role in astrophysical jets with observations suggesting the presence of helical magnetic fields. Here, we present three-dimensional (3D) ideal MHD simulations of the Caltech plasma jet experiment using a magnetic tower scenario as the baseline model. Magnetic fields consist of an initially localized dipole-like poloidal component and a toroidal component that is continuously being injected into the domain. This flux injection mimics the poloidal currents driven by the anode-cathode voltage drop in the experiment. The injected toroidal field stretches the poloidal fields to large distances, while forming a collimated jet along with several other key features. Detailed comparisons between 3D MHD simulations and experimental measurements provide a comprehensive description of the interplay among magnetic force, pressure, and flow effects. In particular, we delineate both the jet structure and the transition process that converts the injected magnetic energy to other forms. With suitably chosen parameters that are derived from experiments, the jet in the simulation agrees quantitatively with the experimental jet in terms of magnetic/kinetic/inertial energy, total poloidal current, voltage, jet radius, and jet propagation velocity. Specifically, the jet velocity in the simulation is proportional to the poloidal current divided by the square root of the jet density, in agreement with both the experiment and analytical theory. This work provides a new and quantitative method for relating experiments, numerical simulations, and astrophysical observation, and demonstrates the possibility of using terrestrial laboratory experiments to study astrophysical jets.

  7. Business Simulation Games: The Hong Kong Experience

    ERIC Educational Resources Information Center

    Chang, Jimmy; Lee, Mary; Ng, Kwan-ling; Moon, Ka-Leung

    2003-01-01

    This article describes the results of a survey of 93 final-year degree students concerning their views toward using Thavikulwat's DEAL: A Business Gaming Simulation. The focus is on students' perception of the usefulness of using computer simulation as a learning tool in a strategic management course. Certain comparison was made with other similar…

  8. Simulating Dynamic Equilibria: A Class Experiment

    NASA Astrophysics Data System (ADS)

    Harrison, John A.; Buckley, Paul D.

    2000-08-01

    A first-order reversible reaction is simulated on an overhead projector using small coins or discs. A simulation is carried out in which initially there are 24 discs representing reactant A and none representing reactant B. At the end of each minute half of the reactant A discs get converted to reactant B, and one quarter of the reactant B discs get converted to reactant A discs. Equilibrium is established with 8 A discs and 16 B discs, and no further net change is observed as the simulation continues. Another simulation beginning with 48 A discs and 0 B discs leads at equilibrium to 16 A discs and 32 B discs. These results illustrate how dynamic equilibria are established and allow the introduction of the concept of an equilibrium constant. Le Châtelier's principle is illustrated by further simulations.

  9. 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.

  10. Climate dynamics experiments using a GCM simulations

    NASA Technical Reports Server (NTRS)

    Fitzjarrald, Dan; Robertson, Franklin R.; Christy, John R.; Lu, H.-I.; Sohn, B.; Srikishen, J.

    1991-01-01

    The study of surface-atmosphere interactions has begun with studies of the effect of altering the ocean and land boundaries. A ten year simulation of global climate using observed sea surface temperature anomalies has begun using the NCAR Community Climate Model (CCM1). The results for low resolution (R15) were computed for the first 8 years of the simulation and compared with the observed surface temperatures and the MSU (Microwave Sounding Unit) observations of tropospheric temperature. A simulation at higher resolution (T42) was done to ascertain the effect of interactive soil hydrology on the system response to an El Nino sea surface temperature perturbation. Initial analysis of this simulations was completed.

  11. Experiences with the MANA simulation tool

    DTIC Science & Technology

    2006-08-01

    indicated as with the title.) Map Aware Non-uniform Automata , MANA, Agent-based, Modelling , Simulation, Future Armoured Vehicle System, FAVS, Advanced... Automata (MANA) agent-based simulation tool has drawn interest in the military Operational Research community. After encountering difficulties with...more resource-intensive higher-fidelity models , the DRDC Valcartier Operational Research (OR) Team considered MANA as a possible tool for fulfilling

  12. Computer simulations and experiments: The case of the Higgs boson

    NASA Astrophysics Data System (ADS)

    Massimi, Michela; Bhimji, Wahid

    2015-08-01

    Simulations have been at the center of an important literature that has debated the extent to which they count as epistemologically on a par with traditional experiments. Critics have raised doubts about simulations being genuine experiments, on the ground that simulations seem to lack a distinctive feature of traditional experiments: i.e., the ability to causally interact with a target system. In this paper, we defend the view that simulations are indeed epistemologically on a par with traditional experiments. We first identify three possible ways of understanding the causal interaction claim. We then focus on the use of simulation in the discovery of the Higgs boson to show that in this paradigmatic case, simulations satisfy all three possible readings of the causal interaction claim.

  13. EBW simulation for MAST and NSTX experiments

    SciTech Connect

    Preinhaelter, J.; Urban, J.; Pavlo, P.; Shevchenko, V.; Valovic, M.; Vahala, G.

    2005-09-26

    The interpretation of EBW emission from spherical tokamaks is nontrivial. We report on a 3D simulation model of this process that incorporates Gaussian beams for the antenna, a full wave solution of EBW-X and EBW-X-O conversions using adaptive finite elements, and EBW ray tracing to determine the radiative temperature. This model is then used to interpret the experimental results from MAST and NSTX. EBW for ELM free H-modes in MAST suggests that the magnetic equilibrium determined by the EFIT code does not adequately represent the B-field within the transport barrier. Using the EBW signal for the reconstruction of the radial profile of the magnetic field, we determine a new equilibrium and see that the EBW simulation now yields better agreement with experimental results. EBW simulations yield excellent results for the time development of the plasma temperature as measured by the EBW radiometer on NSTX.

  14. Comparing simulation of plasma turbulence with experiment

    NASA Astrophysics Data System (ADS)

    Ross, David W.; Bravenec, Ronald V.; Dorland, William; Beer, Michael A.; Hammett, G. W.; McKee, George R.; Fonck, Raymond J.; Murakami, Masanori; Burrell, Keith H.; Jackson, Gary L.; Staebler, Gary M.

    2002-01-01

    The direct quantitative correspondence between theoretical predictions and the measured plasma fluctuations and transport is tested by performing nonlinear gyro-Landau-fluid simulations with the GRYFFIN (or ITG) code [W. Dorland and G. W. Hammett, Phys. Fluids B 5, 812 (1993); M. A. Beer and G. W. Hammett, Phys. Plasmas 3, 4046 (1996)]. In an L-mode reference discharge in the DIII-D tokamak [J. L. Luxon and L. G. Davis, Fusion Technol. 8, 441 (1985)], which has relatively large fluctuations and transport, the turbulence is dominated by ion temperature gradient (ITG) modes. Trapped electron modes and impurity drift waves also play a role. Density fluctuations are measured by beam emission spectroscopy [R. J. Fonck, P. A. Duperrex, and S. F. Paul, Rev. Sci. Instrum. 61, 3487 (1990)]. Experimental fluxes and corresponding diffusivities are analyzed by the TRANSP code [R. J. Hawryluk, in Physics of Plasmas Close to Thermonuclear Conditions, edited by B. Coppi, G. G. Leotta, D. Pfirsch, R. Pozzoli, and E. Sindoni (Pergamon, Oxford, 1980), Vol. 1, p. 19]. The shape of the simulated wave number spectrum is close to the measured one. The simulated ion thermal transport, corrected for E×B low shear, exceeds the experimental value by a factor of 1.5 to 2.0. The simulation overestimates the density fluctuation level by an even larger factor. On the other hand, the simulation underestimates the electron thermal transport, which may be accounted for by modes that are not accessible to the simulation or to the BES measurement.

  15. Dynamic System Simulation of the KRUSTY Experiment

    SciTech Connect

    Klein, Steven Karl; Kimpland, Robert Herbert

    2016-05-09

    The proposed KRUSTY experiment is a demonstration of a reactor operating at power. The planned experimental configuration includes a highly enriched uranium (HEU) reflected core, cooled by multiple heat pipes leading to Stirling engines for primary heat rejection. Operating power is expected to be approximately four (4) to five (5) kilowatts with a core temperature above 1,000 K. No data is available on any historical reactor employing HEU metal that operated over the temperature range required for the KRUSTY experiment. Further, no reactor has operated with heat pipes as the primary cooling mechanism. Historic power reactors have employed either natural or forced convection so data on their operation is not directly applicable to the KRUSTY experiment. The primary purpose of the system model once developed and refined by data from these component experiments, will be used to plan the KRUSTY experiment. This planning will include expected behavior of the reactor from start-up, through various transient conditions where cooling begins to become present and effective, and finally establishment of steady-state. In addition, the model can provide indicators of anticipated off-normal events and appropriate operator response to those conditions. This information can be used to develop specific experiment operating procedures and aids to guide the operators in conduct of the experiment.

  16. 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.

  17. 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.

  18. Development of a neuropsychological battery for the Leukoaraiosis and Disability in the Elderly Study (LADIS): experience and baseline data.

    PubMed

    Madureira, Sofia; Verdelho, Ana; Ferro, José; Basile, Anna-Maria; Chabriat, Hugues; Erkinjuntti, Timo; Fazekas, Franz; Hennerici, Michael; O'brien, John; Pantoni, Leonardo; Salvadori, Emilia; Scheltens, Philip; Visser, Marieke C; Wahlund, Lars-Olof; Waldemar, Gunhild; Wallin, Anders; Inzitari, Domenico

    2006-01-01

    The relationship between age-related white matter changes and cognitive performance in independent elderly people is still not clear. The Leukoaraiosis and Disability in the Elderly study (LADIS) involves 11 European centers. It aims to assess the role of the age-related white matter changes as an independent factor in the transition to disability, and in cognitive performance of an independent elderly population. A comprehensive neuropsychological battery was constructed in order to harmonize the cognitive assessment across countries. Patients were evaluated at baseline and during the 3-year follow-up with the Mini-Mental State Examination, a modified version of the VADAS-Cog (Alzheimer's Dementia Assessment Scale plus tests of Delayed recall, Symbol digit, Digit span, Maze, Digit cancellation and Verbal fluency), Trail making and Stroop test. Six hundred thirty-eight patients (mean age 74 +/- 5 years; mean educational level 10 +/- 4, F/M: 351/287) were included in this study. Neuropsychological data were analyzed test by test and also grouped in three compound measures (executive, memory and speed/motor control domains). Older subjects (>74 years) performed significantly worse than younger subjects on the ADAS-Mod and on the tests of memory (t(631) = 3.25; p = 0.001), executive functions (t(581) = 4.68; p = 0.001) and speed/motor control (t(587) = 4.01; p = 0.001). Participants with higher educational level (>8 years of school) showed better performances on the compound measures for memory (t(631) = 3.25; p = 0.001), executive functions (t(581) = 4.68; p = 0.001) and speed/motor control (t(587) = 4.01; p = 0.001). Using multiple regression analysis models to study the influence of demographic variables on cognitive performance, age and education remained important variables influencing test performance. In the LADIS population baseline data, older age and lower educational levels negatively influence neuropsychological performance.

  19. Actual Operation Simulation of RESSOX Ground Experiments

    DTIC Science & Technology

    2010-11-01

    One, every 30 s , we expect to receive orbit forecast information in the International Terrestrial Reference Frame (ITRF) for a duration of 3 minutes...values, every 30 s , RC will receive orbit estimation and forecast values in the International Terrestrial Reference Frame (ITRF) for a duration of 3...Fig. 3. System diagram of Experiment Two using QZSS. 30 s Orbit estimation values

  20. Tunable nonlinear superconducting metamaterials: Experiment and simulation

    NASA Astrophysics Data System (ADS)

    Trepanier, Melissa

    I present experimental and numerical simulation results for two types of nonlinear tunable superconducting metamaterials: 2D arrays of rf SQUIDs (radio frequency superconducting quantum interference devices) as magnetic metamaterials and arrays of Josephson junction-loaded wires as electric metamaterials. The effective inductance of a Josephson junction is sensitive to dc current, temperature, and rf current. I took advantage of this property to design arrays of Josephson junction-loaded wires that present a tunable cutoff frequency and thus a tunable effective permittivity for propagating electromagnetic waves in a one-conductor waveguide. I measured the response of the metamaterial to each tuning parameter and found agreement with numerical simulations that employ the RCSJ (resistively and capacitively shunted junction) model. An rf SQUID is an analogue of an SRR (split ring resonator) with the gap capacitance replaced with a Josephson junction. Like the SRR the SQUID is a resonant structure with a frequency-dependent effective permeability. The difference between the SQUID and the SRR is that the effective inductance and thus effective permeability of the SQUID can be tuned with dc and rf flux, and temperature. Individual rf SQUID meta-atoms and two-dimensional arrays were designed and measured as a function of each tuning parameter and I have found excellent agreement with numerical simulations. There is also an interesting transparency feature that occurs for intermediate rf flux values. The tuning of SQUID arrays has a similar character to the tuning of individual rf SQUID meta-atoms. However, I found that the coupling between the SQUIDs increases the resonant frequency, decreases dc flux tuning, and introduces additional resonant modes. Another feature of arrays is disorder which suppresses the coherence of the response and negatively impacts the emergent properties of the metamaterial. The disorder was experimentally found to be mainly due to a dc flux

  1. 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.

  2. Solution to the indexing problem of frequency domain simulation experiments

    NASA Technical Reports Server (NTRS)

    Mitra, Mousumi; Park, Stephen K.

    1991-01-01

    A frequency domain simulation experiment is one in which selected system parameters are oscillated sinusoidally to induce oscillations in one or more system statistics of interest. A spectral (Fourier) analysis of these induced oscillations is then performed. To perform this spectral analysis, all oscillation frequencies must be referenced to a common, independent variable - an oscillation index. In a discrete-event simulation, the global simulation clock is the most natural choice for the oscillation index. However, past efforts to reference all frequencies to the simulation clock generally yielded unsatisfactory results. The reason for these unsatisfactory results is explained in this paper and a new methodology which uses the simulation clock as the oscillation index is presented. Techniques for implementing this new methodology are demonstrated by performing a frequency domain simulation experiment for a network of queues.

  3. Josephson Junction Arrays with Positional Disorder: Experiments and Simulations

    DTIC Science & Technology

    1988-02-01

    Caislinuo an loe*@*. old* it no.ee.q Aid taoncitI y IOcA flMwb~wJ Josephson junctions Positional disorder Monta Carlo simulations 20. AUSTRACT (Conoidiie an...both experiments and Monte Carlo siimulations. We have fabricated 50 x 50 arrays of Pb/Cu proximity-effect junctions, with controlled positional...However, our experiments show no evidence for the predicted reentrant phase transition. Our Monte Carlo simulations of XY spin systems with positional

  4. Simulation of the Viking biology experiments: an overview.

    PubMed

    Klein, H P

    1979-12-01

    Several ground-based investigations have been carried out since the Viking biology results were received from Mars. Many of these have resulted in reasonable simulations of the Martian data, using as analogues of Mars either strong oxidants, UV-treated materials, iron-containing clays, or iron salts. The ambiguity between the GCMS experiment, in which no organic compounds were found on Mars, and the Labeled Release experiment, in which added organics were decomposed, may well be accounted for by these simulations.

  5. 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.

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

    SciTech Connect

    Wescott, E.M.

    1994-04-01

    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.

  7. 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…

  8. 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.…

  9. Designing Nursing Simulation Clinical Experiences to Promote Critical Inquiry

    ERIC Educational Resources Information Center

    Beattie, Bev; Koroll, Donna; Price, Susan

    2010-01-01

    The use of high fidelity simulation (HFS) learning opportunities in nursing education has received increased attention in the literature. This article describes the design of a systematic framework used to promote critical inquiry and provide meaningful simulation clinical experiences for second year nursing students. Critical inquiry, as defined…

  10. 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…

  11. 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.

  12. Simulation of physiology experiments--an alternative to animal use.

    PubMed

    Nageswari, K Sri; Devi, M Syamala; Sharma, Rajeev

    2007-01-01

    Amphibian experiments on nerve-muscle preparation and heart are essential as per first year MBBS practical syllabus, for learning basic concepts in Physiology. Need was felt to design and develop computer based simulation software as an alternative to animal use, due to growing concern and stringent laws imposed by animal ethical bodies. Computer algorithms were developed for 13 amphibian experiments, by manually tracing the graphs obtained through mechanical experimentation and storing the X, Y coordinates for the end points of each line segment as data base tables. By retrieving the data base tables, one for each experiment, the computer simulated graphs were drawn using Visual Basic 6 with timer control and Macromedia Flash for animation effects. A CD-ROM consisting of the software for computer simulation of all the amphibian experiments, as an alternative to the conventional animal experiments, has been developed for the benefit of medical students across the country, as a useful active learning tool.

  13. 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.

  14. A Very-Short-Baseline Time Transfer Experiment Using Two Geodetic-Quality GPS Receivers and Carrier Phase Techniques

    DTIC Science & Technology

    1998-12-01

    recently purchased Ashtech 212-T receiver and an ol&r AUen Osborne Associates (AOA) TTR- 4P receiver. Data collected from these geodetic-quality GPS...commercial software. In this paper the results of a very-shorkbaseline common-clock experiment between NPL’s Ashtech Z12-T and AOA TTR- 4P geodetic...8217 performance. 2 GEODETIC GPS HARDWARE AT NPL NPL possesses two geodetic quality GPS receivers, an Ashtech Z12-T and an AOrZ TTR- 4P . The hardware

  15. 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.

  16. "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.

  17. 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.

  18. Analysis of a DNA simulation model through hairpin melting experiments

    PubMed Central

    Linak, Margaret C.; Dorfman, Kevin D.

    2010-01-01

    We compare the predictions of a two-bead Brownian dynamics simulation model to melting experiments of DNA hairpins with complementary AT or GC stems and noninteracting loops in buffer A. This system emphasizes the role of stacking and hydrogen bonding energies, which are characteristics of DNA, rather than backbone bending, stiffness, and excluded volume interactions, which are generic characteristics of semiflexible polymers. By comparing high throughput data on the open-close transition of various DNA hairpins to the corresponding simulation data, we (1) establish a suitable metric to compare the simulations to experiments, (2) find a conversion between the simulation and experimental temperatures, and (3) point out several limitations of the model, including the lack of G-quartets and cross stacking effects. Our approach and experimental data can be used to validate similar coarse-grained simulation models. PMID:20886965

  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. 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.

  1. 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.

  2. Visualizing Hyporheic Flow Through Bedforms Using Dye Experiments and Simulation.

    PubMed

    Stonedahl, Susa H; Roche, Kevin R; Stonedahl, Forrest; Packman, Aaron I

    2015-11-18

    Advective exchange between the pore space of sediments and the overlying water column, called hyporheic exchange in fluvial environments, drives solute transport in rivers and many important biogeochemical processes. To improve understanding of these processes through visual demonstration, we created a hyporheic flow simulation in the multi-agent computer modeling platform NetLogo. The simulation shows virtual tracer flowing through a streambed covered with two-dimensional bedforms. Sediment, flow, and bedform characteristics are used as input variables for the model. We illustrate how these simulations match experimental observations from laboratory flume experiments based on measured input parameters. Dye is injected into the flume sediments to visualize the porewater flow. For comparison virtual tracer particles are placed at the same locations in the simulation. This coupled simulation and lab experiment has been used successfully in undergraduate and graduate laboratories to directly visualize river-porewater interactions and show how physically-based flow simulations can reproduce environmental phenomena. Students took photographs of the bed through the transparent flume walls and compared them to shapes of the dye at the same times in the simulation. This resulted in very similar trends, which allowed the students to better understand both the flow patterns and the mathematical model. The simulations also allow the user to quickly visualize the impact of each input parameter by running multiple simulations. This process can also be used in research applications to illustrate basic processes, relate interfacial fluxes and porewater transport, and support quantitative process-based modeling.

  3. 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.

  4. 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.

  5. 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

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. Simulations of NOVA direct-drive hydrodynamics experiments

    SciTech Connect

    Weber, S.V,; Glendinning, S.G.

    1991-04-15

    Directly driven Rayleigh-Taylor instability growth experiments being performed on NOVA have been simulated using the computer code, LASNEX. Foils with single-wavelength imposed surface perturbations have been driven with a single beam of 0.53 {mu}m light, employing smoothing by spectral dispersion (SSD). In addition to simulating foils with imposed surface perturbations, we have simulated flat foils driven by beams with time-dependent intensity modulation resulting from the NOVA implementation of SSD. These simulations show the development of large amplitude modulation of the target from residual intensity nonuniformities. Structure seeded by beam nonuniformity would overwhelm modulation resulting from imposed surface perturbations of sub-micron initial amplitude, but is predicted to develop sufficiently slowly that we expect to observe growth of perturbations with initial amplitudes of several microns. In other NOVA experiments, flat foils with an embedded brominated spectroscopic tracer layer are used in infer mass ablation rates. SSD drive is predicted to yield ablation rates in better agreement with 1-D simulations than drive from a beam with random phase plates (RPP) alone. Simulations of foils driven with RPP beams show enhanced ablation rates because modulation of the ablation front increases its surface area. Line emission from the seed is first seen at cold spots in the beam, which create protruding spikes at the ablation front. Simulation results will be compared with early experimental data. 5 refs., 14 figs.

  11. Premission and postmission simulation studies of the foot-controlled maneuvering unit for Skylab experiment T-020. [astronaut maneuvering equipment - space environment simulation

    NASA Technical Reports Server (NTRS)

    Hewes, D. E.; Glover, K. E.

    1975-01-01

    A Skylab experiment was conducted to study the maneuvering capabilities of astronauts using a relatively simple self-locomotive device, referred to as the foot-controlled maneuvering unit, and to evaluate the effectiveness of ground-based facilities simulating the operation of this device in weightless conditions of space. Some of the special considerations given in the definition and development of the experiment as related to the two ground-based simulators are reviewed. These simulators were used to train the test subjects and to obtain baseline data which could be used for comparison with the in-flight tests that were performed inside the Skylab orbital workshop. The results of both premission and postmission tests are discussed, and subjective comparisons of the in-flight and ground-based test conditions are presented.

  12. 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.

  13. 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)

  14. 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)

  15. 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…

  16. Experiment and simulation for CSI: What are the missing links?

    NASA Technical Reports Server (NTRS)

    Belvin, W. Keith; Park, K. C.

    1989-01-01

    Viewgraphs on experiment and simulation for control structure interaction (CSI) are presented. Topics covered include: control structure interaction; typical control/structure interaction system; CSI problem classification; actuator/sensor models; modeling uncertainty; noise models; real-time computations; and discrete versus continuous.

  17. 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…

  18. Characteristics of Effective Clinical Teachers in Simulated Clinical Experiences Compared to Traditional Clinical Experiences

    ERIC Educational Resources Information Center

    Sieh-Bliss, Selina

    2014-01-01

    While there is evidence in the literature measuring effective clinical teacher characteristics in traditional experiences, little is known of effective characteristics expected from clinical teachers during simulated clinical experiences. This study examined which clinical teaching behaviors and characteristics are perceived by nursing students'…

  19. Quantum chemistry simulation on quantum computers: theories and experiments.

    PubMed

    Lu, Dawei; Xu, Boruo; Xu, Nanyang; Li, Zhaokai; Chen, Hongwei; Peng, Xinhua; Xu, Ruixue; Du, Jiangfeng

    2012-07-14

    It has been claimed that quantum computers can mimic quantum systems efficiently in the polynomial scale. Traditionally, those simulations are carried out numerically on classical computers, which are inevitably confronted with the exponential growth of required resources, with the increasing size of quantum systems. Quantum computers avoid this problem, and thus provide a possible solution for large quantum systems. In this paper, we first discuss the ideas of quantum simulation, the background of quantum simulators, their categories, and the development in both theories and experiments. We then present a brief introduction to quantum chemistry evaluated via classical computers followed by typical procedures of quantum simulation towards quantum chemistry. Reviewed are not only theoretical proposals but also proof-of-principle experimental implementations, via a small quantum computer, which include the evaluation of the static molecular eigenenergy and the simulation of chemical reaction dynamics. Although the experimental development is still behind the theory, we give prospects and suggestions for future experiments. We anticipate that in the near future quantum simulation will become a powerful tool for quantum chemistry over classical computations.

  20. Lattice Boltzmann modeling of directional wetting: Comparing simulations to experiments

    NASA Astrophysics Data System (ADS)

    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.

  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.

  2. Universality between Experiment and Simulation of a Diblock Copolymer Melt.

    PubMed

    Beardsley, Thomas M; Matsen, Mark W

    2016-11-18

    The equivalent behavior among analogous block copolymer systems involving chemically distinct molecules or mathematically different models has long hinted at an underlying universality, but only recently has it been rigorously demonstrated by matching results from different simulations. The profound implication of universality is that simple coarse-grained models can be calibrated so as to provide quantitatively accurate predictions to experiment. Here, we provide the first compelling demonstration of this by simulating a polyisoprene-polylactide diblock copolymer melt using a previously calibrated lattice model. The simulation successfully predicts the peak in the disordered-state structure function, the position of the order-disorder transition, and the latent heat of the transition in excellent quantitative agreement with experiment. This could mark a new era of precision in the field of block copolymer research.

  3. Universality between Experiment and Simulation of a Diblock Copolymer Melt

    NASA Astrophysics Data System (ADS)

    Beardsley, Thomas M.; Matsen, Mark W.

    2016-11-01

    The equivalent behavior among analogous block copolymer systems involving chemically distinct molecules or mathematically different models has long hinted at an underlying universality, but only recently has it been rigorously demonstrated by matching results from different simulations. The profound implication of universality is that simple coarse-grained models can be calibrated so as to provide quantitatively accurate predictions to experiment. Here, we provide the first compelling demonstration of this by simulating a polyisoprene-polylactide diblock copolymer melt using a previously calibrated lattice model. The simulation successfully predicts the peak in the disordered-state structure function, the position of the order-disorder transition, and the latent heat of the transition in excellent quantitative agreement with experiment. This could mark a new era of precision in the field of block copolymer research.

  4. Relating a Jet-Surface Interaction Experiment to a Commercial Supersonic Transport Aircraft Using Numerical Simulations

    NASA Technical Reports Server (NTRS)

    Dippold, Vance F. III; Friedlander, David

    2017-01-01

    Reynolds-Averaged Navier-Stokes (RANS) simulations were performed for a commercial supersonic transport aircraft concept and experimental hardware models designed to represent the installed propulsion system of the conceptual aircraft in an upcoming test campaign. The purpose of the experiment is to determine the effects of jet-surface interactions from supersonic aircraft on airport community noise. RANS simulations of the commercial supersonic transport aircraft concept were performed to relate the representative experimental hardware to the actual aircraft. RANS screening simulations were performed on the proposed test hardware to verify that it would be free from potential rig noise and to predict the aerodynamic forces on the model hardware to assist with structural design. The simulations showed a large region of separated flow formed in a junction region of one of the experimental configurations. This was dissimilar with simulations of the aircraft and could invalidate the noise measurements. This configuration was modified and a subsequent RANS simulation showed that the size of the flow separation was greatly reduced. The aerodynamic forces found on the experimental models were found to be relatively small when compared to the expected loads from the model’s own weight.Reynolds-Averaged Navier-Stokes (RANS) simulations were completed for two configurations of a three-stream inverted velocity profile (IVP) nozzle and a baseline single-stream round nozzle (mixed-flow equivalent conditions). For the Sideline and Cutback flow conditions, while the IVP nozzles did not reduce the peak turbulent kinetic energy on the lower side of the jet plume, the IVP nozzles did significantly reduce the size of the region of peak turbulent kinetic energy when compared to the jet plume of the baseline nozzle cases. The IVP nozzle at Sideline conditions did suffer a region of separated flow from the inner stream nozzle splitter that did produce an intense, but small, region of

  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. Apollo experience report: Guidance and control systems. Engineering simulation program

    NASA Technical Reports Server (NTRS)

    Gilbert, D. W.

    1973-01-01

    The Apollo Program experience from early 1962 to July 1969 with respect to the engineering-simulation support and the problems encountered is summarized in this report. Engineering simulation in support of the Apollo guidance and control system is discussed in terms of design analysis and verification, certification of hardware in closed-loop operation, verification of hardware/software compatibility, and verification of both software and procedures for each mission. The magnitude, time, and cost of the engineering simulations are described with respect to hardware availability, NASA and contractor facilities (for verification of the command module, the lunar module, and the primary guidance, navigation, and control system), and scheduling and planning considerations. Recommendations are made regarding implementation of similar, large-scale simulations for future programs.

  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. Nursing students' self-assessment of their simulation experiences.

    PubMed

    Cato, Mary L; Lasater, Kathie; Peeples, Alycia Isabella

    2009-01-01

    This article describes a self-evaluation and feedback strategy used by nursing students and simulation faculty in a junior-level adult acute care course. Simulations are developed and implemented with the intention of furthering students' clinical judgment skills. A clinical judgment rubric, based on the Tanner Model of Clinical Judgment, is used as a self-assessment tool. The rubric describes the development of clinical judgment over four levels and is scored by students as they reflect on their practice. In addition to using the rubric's descriptors to rate themselves (Beginning, Developing, Accomplished, and Exemplary), the students apply an evidence-based process, citing simulation examples of their clinical thinking as support for their ratings. Simulation faculty respond to the postings, affirming students' observations or helping them experience a different perspective, and offer help to move toward the next stage of clinical judgment development. The postings offer clinical faculty insight into clinical judgment processes observed in the practicum settings.

  9. 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.

  10. 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).

  11. Complete Monte Carlo Simulation of Neutron Scattering Experiments

    NASA Astrophysics Data System (ADS)

    Drosg, M.

    2011-12-01

    In the far past, it was not possible to accurately correct for the finite geometry and the finite sample size of a neutron scattering set-up. The limited calculation power of the ancient computers as well as the lack of powerful Monte Carlo codes and the limitation in the data base available then prevented a complete simulation of the actual experiment. Using e.g. the Monte Carlo neutron transport code MCNPX [1], neutron scattering experiments can be simulated almost completely with a high degree of precision using a modern PC, which has a computing power that is ten thousand times that of a super computer of the early 1970s. Thus, (better) corrections can also be obtained easily for previous published data provided that these experiments are sufficiently well documented. Better knowledge of reference data (e.g. atomic mass, relativistic correction, and monitor cross sections) further contributes to data improvement. Elastic neutron scattering experiments from liquid samples of the helium isotopes performed around 1970 at LANL happen to be very well documented. Considering that the cryogenic targets are expensive and complicated, it is certainly worthwhile to improve these data by correcting them using this comparatively straightforward method. As two thirds of all differential scattering cross section data of 3He(n,n)3He are connected to the LANL data, it became necessary to correct the dependent data measured in Karlsruhe, Germany, as well. A thorough simulation of both the LANL experiments and the Karlsruhe experiment is presented, starting from the neutron production, followed by the interaction in the air, the interaction with the cryostat structure, and finally the scattering medium itself. In addition, scattering from the hydrogen reference sample was simulated. For the LANL data, the multiple scattering corrections are smaller by a factor of five at least, making this work relevant. Even more important are the corrections to the Karlsruhe data due to the

  12. Comparing ballistic wounds with experiments on body simulator.

    PubMed

    Bresson, F; Franck, O

    2010-05-20

    This paper demonstrates how ballistic experiments on body simulator can bring a key information in the forensic science field. In the investigated case, a hunter was shot by accident in the back. Two hunters were suspected of having inadvertently shot towards the victim. The deadly bullet left the body and cannot be found on the scene neither in the body. The only way to discriminate the two options was to perform ballistic tests in body simulators. Even though the knowledge about body simulators is not enough advanced yet to expect accurate quantitative results, it was supposed to fully discriminate the two investigated cases as its respective impact energy are highly different (respectively 1200J and 2400J). For each investigated possibility, bullet's expansion state and body wounds were simulated. Bullet impact characteristics were determined by measuring the muzzle velocity, compute the impact velocity in the considered range (the position of each hunter is accurately known). Reloading cartridges allowed to reproduce accuretaly the corresponding velocity. The body was simulated by 3 different means in order to explore the accuracy of the simulation process. We demonstrated that the reported case is situated in a velocity/energy range in which body simulators do not need to be particularly accurate to reproduce the bullet expansion/non-expansion state. It furthermore demonstrated that only one case is compatible with the ballistic wounds of the victim. In the other case, the bullet's expansion would lead to a completely different wound shape.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. A system for designing and simulating particle physics experiments

    NASA Astrophysics Data System (ADS)

    Żelazny, Roman; Strzałkowski, Piotr

    1987-01-01

    In view of the rapid development of experimental facilities and their costs, the systematic design and preparation of particle physics experiments have become crucial. A software system is proposed as an aid for the experimental designer, mainly for experimental geometry analysis and experimental simulation. The following model is adopted: the description of an experiment is formulated in a language (here called XL) and put by its processor in a data base. The language is based on the entity-relationship-attribute approach. The information contained in the data base can be reported and analysed by an analyser (called XA) and modifications can be made at any time. In particular, the Monte Carlo methods can be used in experiment simulation for both physical phenomena in experimental set-up and detection analysis. The general idea of the system is based on the design concept of ISDOS project information systems. The characteristics of the simulation module are similar to those of the CERN Geant system, but some extensions are proposed. The system could be treated as a component of a greater, integrated software environment for the design of particle physics experiments, their monitoring and data processing.

  19. Brain simulation of action may be grounded in physical experience.

    PubMed

    Olsson, C J; Nyberg, Lars

    2011-12-01

    An intriguing quality of our brain is that when actions are imagined, corresponding brain regions are recruited as when the actions are actually performed. It has been hypothesized that the similarity between real and simulated actions depends on the nature of motor representations. Here we tested this hypothesis by examining S.D., who never used her legs but is an elite wheel chair athlete. Controls recruited motor brain regions during imagery of stair walking and frontal regions during imagery of wheel chair slalom. S.D. showed the opposite pattern. Thus, brain simulation of actions may be grounded in specific physical experiences.

  20. Virtual experiments: Combining realistic neutron scattering instrument and sample simulations

    NASA Astrophysics Data System (ADS)

    Farhi, E.; Hugouvieux, V.; Johnson, M. R.; Kob, W.

    2009-08-01

    A new sample component is presented for the Monte Carlo, ray-tracing program, McStas, which is widely used to simulate neutron scattering instruments. The new component allows the sample to be described by its material dynamic structure factor, which is separated into coherent and incoherent contributions. The effects of absorption and multiple scattering are treated and results from simulations and previous experiments are compared. The sample component can also be used to treat any scattering material which may be close to the sample and therefore contaminates the total, measured signal.

  1. 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.

  2. 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.

  3. Simulations of Laboratory Astrophysics Experiments using the CRASH code

    NASA Astrophysics Data System (ADS)

    Trantham, Matthew; Kuranz, Carolyn; Manuel, Mario; Keiter, Paul; Drake, R. P.

    2014-10-01

    Computer simulations can assist in the design and analysis of laboratory astrophysics experiments. The Center for Radiative Shock Hydrodynamics (CRASH) at the University of Michigan developed a code that has been used to design and analyze high-energy-density experiments on OMEGA, NIF, and other large laser facilities. This Eulerian code uses block-adaptive mesh refinement (AMR) with implicit multigroup radiation transport, electron heat conduction and laser ray tracing. This poster/talk will demonstrate some of the experiments the CRASH code has helped design or analyze including: Kelvin-Helmholtz, Rayleigh-Taylor, imploding bubbles, and interacting jet experiments. This work is funded by the Predictive Sciences Academic Alliances Program in NNSA-ASC via Grant DEFC52-08NA28616, by the NNSA-DS and SC-OFES Joint Program in High-Energy-Density Laboratory Plasmas, Grant Number DE-NA0001840, and by the National Laser User Facility Program, Grant Number DE-NA0000850.

  4. 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.

  5. On integrating large eddy simulation and laboratory turbulent flow experiments.

    PubMed

    Grinstein, Fernando F

    2009-07-28

    Critical issues involved in large eddy simulation (LES) experiments relate to the treatment of unresolved subgrid scale flow features and required initial and boundary condition supergrid scale modelling. The inherently intrusive nature of both LES and laboratory experiments is noted in this context. Flow characterization issues becomes very challenging ones in validation and computational laboratory studies, where potential sources of discrepancies between predictions and measurements need to be clearly evaluated and controlled. A special focus of the discussion is devoted to turbulent initial condition issues.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. Numerical prediction experiments simulating the impact of mesoscale satellite data

    NASA Technical Reports Server (NTRS)

    Kreitzberg, C. W.

    1979-01-01

    Recent developments in mesometeorology are summarized to place this research in perspective. Recent advances in computer analysis and forecast system development that provide the basis for the simulation tests are discussed. The impact of NIMBUS-6 humidity data on analyses off the West Coast are shown and incorporation of geopotential gradient data is discussed. Experiments to demonstrate the feasibility of incorporating satellite-derived wind fields in mesoscale severe storm models are mentioned briefly.

  11. Fatigue Damage of Collagenous Tissues: Experiment, Modeling and Simulation Studies

    PubMed Central

    Martin, Caitlin; Sun, Wei

    2017-01-01

    Mechanical fatigue damage is a critical issue for soft tissues and tissue-derived materials, particularly for musculoskeletal and cardiovascular applications; yet, our understanding of the fatigue damage process is incomplete. Soft tissue fatigue experiments are often difficult and time-consuming to perform, which has hindered progress in this area. However, the recent development of soft-tissue fatigue-damage constitutive models has enabled simulation-based fatigue analyses of tissues under various conditions. Computational simulations facilitate highly controlled and quantitative analyses to study the distinct effects of various loading conditions and design features on tissue durability; thus, they are advantageous over complex fatigue experiments. Although significant work to calibrate the constitutive models from fatigue experiments and to validate predictability remains, further development in these areas will add to our knowledge of soft-tissue fatigue damage and will facilitate the design of durable treatments and devices. In this review, the experimental, modeling, and simulation efforts to study collagenous tissue fatigue damage are summarized and critically assessed. PMID:25955007

  12. Hydrodynamic simulations of gaseous Argon shock compression experiments

    NASA Astrophysics Data System (ADS)

    Garcia, Daniel B.; Dattelbaum, Dana M.; Goodwin, Peter M.; Sheffield, Stephen A.; Morris, John S.; Gustavsen, Richard L.; Burkett, Michael W.

    2017-01-01

    The lack of published Ar gas shock data motivated an evaluation of the Ar Equation of State (EOS) in gas phase initial density regimes. In particular, these regimes include initial pressures in the range of 13.8 - 34.5 bar (0.025 - 0.056 g/ cm3) 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 Ar gas through Pagosa numerical simulations utilizing the SESAME equation of state. Pagosa is a Los Alamos National Laboratory 2-D and 3-D Eulerian continuum dynamics code 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 Ar 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, and reasonable comparisons for the ionization temperatures.

  13. Hypervelocity impacts into porous graphite: experiments and simulations

    NASA Astrophysics Data System (ADS)

    Hébert, D.; Seisson, G.; Rullier, J.-L.; Bertron, I.; Hallo, L.; Chevalier, J.-M.; Thessieux, C.; Guillet, F.; Boustie, M.; Berthe, L.

    2017-01-01

    We present experiments and numerical simulations of hypervelocity impacts of 0.5 mm steel spheres into graphite, for velocities ranging between 1100 and 4500 m s-1. Experiments have evidenced that, after a particular striking velocity, depth of penetration no longer increases but decreases. Moreover, the projectile is observed to be trapped below the crater surface. Using numerical simulations, we show how this experimental result can be related to both materials, yield strength. A Johnson-Cook model is developed for the steel projectile, based on the literature data. A simple model is proposed for the graphite yield strength, including a piecewise pressure dependence of the Drucker-Prager form, which coefficients have been chosen to reproduce the projectile penetration depth. Comparisons between experiments and simulations are presented and discussed. The damage properties of both materials are also considered, by using a threshold on the first principal stress as a tensile failure criterion. An additional compressive failure model is also used for graphite when the equivalent strain reaches a maximum value. We show that the experimental crater diameter is directly related to the graphite spall strength. Uncertainties on the target yield stress and failure strength are estimated. This article is part of the themed issue 'Experimental testing and modelling of brittle materials at high strain rates'.

  14. Simulations of Laboratory Astrophysics Experiments using the CRASH code

    NASA Astrophysics Data System (ADS)

    Trantham, Matthew; Kuranz, Carolyn; Fein, Jeff; Wan, Willow; Young, Rachel; Keiter, Paul; Drake, R. Paul

    2015-11-01

    Computer simulations can assist in the design and analysis of laboratory astrophysics experiments. The Center for Radiative Shock Hydrodynamics (CRASH) at the University of Michigan developed a code that has been used to design and analyze high-energy-density experiments on OMEGA, NIF, and other large laser facilities. This Eulerian code uses block-adaptive mesh refinement (AMR) with implicit multigroup radiation transport, electron heat conduction and laser ray tracing. This poster will demonstrate some of the experiments the CRASH code has helped design or analyze including: Kelvin-Helmholtz, Rayleigh-Taylor, magnetized flows, jets, and laser-produced plasmas. This work is funded by the following grants: DEFC52-08NA28616, DE-NA0001840, and DE-NA0002032.

  15. 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.

  16. 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.

  17. Simulations of NOVA direct-drive Rayleigh-Taylor experiments

    SciTech Connect

    Weber, S.V.

    1990-11-03

    Directly driven Rayleigh-Taylor instability growth experiments being performed on NOVA have been simulated using the computer code, LASNEX. These experiments employ beams smoothed with random phase plates (RPP), and will later include smoothing by spectral dispersion (SSD). Samples are CH foils with or without imposed sinusoidal surface perturbations. Perturbation growth is diagnosed by means of x-ray backlighting. Calculated growth rates are fairly flat across the wavelength range of 20--80 {mu}m which can be accessed experimentally, and are moderately suppressed below classical growth rates. Perturbations of large enough initial amplitude that the contrast in the x-ray image is measurable from the start of the experiment quickly grow into the nonlinear regime. Smaller initial amplitudes result in a longer interval of linear growth, but the initial perturbation will not be detectable in the data. Structure which is predicted to develop from speckles in the RPP beam pattern, with and without SSD, is also presented.

  18. Complete Monte Carlo Simulation of Neutron Scattering Experiments

    SciTech Connect

    Drosg, M.

    2011-12-13

    In the far past, it was not possible to accurately correct for the finite geometry and the finite sample size of a neutron scattering set-up. The limited calculation power of the ancient computers as well as the lack of powerful Monte Carlo codes and the limitation in the data base available then prevented a complete simulation of the actual experiment. Using e.g. the Monte Carlo neutron transport code MCNPX [1], neutron scattering experiments can be simulated almost completely with a high degree of precision using a modern PC, which has a computing power that is ten thousand times that of a super computer of the early 1970s. Thus, (better) corrections can also be obtained easily for previous published data provided that these experiments are sufficiently well documented. Better knowledge of reference data (e.g. atomic mass, relativistic correction, and monitor cross sections) further contributes to data improvement. Elastic neutron scattering experiments from liquid samples of the helium isotopes performed around 1970 at LANL happen to be very well documented. Considering that the cryogenic targets are expensive and complicated, it is certainly worthwhile to improve these data by correcting them using this comparatively straightforward method. As two thirds of all differential scattering cross section data of {sup 3}He(n,n){sup 3}He are connected to the LANL data, it became necessary to correct the dependent data measured in Karlsruhe, Germany, as well. A thorough simulation of both the LANL experiments and the Karlsruhe experiment is presented, starting from the neutron production, followed by the interaction in the air, the interaction with the cryostat structure, and finally the scattering medium itself. In addition, scattering from the hydrogen reference sample was simulated. For the LANL data, the multiple scattering corrections are smaller by a factor of five at least, making this work relevant. Even more important are the corrections to the Karlsruhe data

  19. 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.

  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. Engineering and simulation of life sciences Spacelab experiments.

    PubMed

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

    1979-10-01

    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.

  2. 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.

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

    NASA Astrophysics Data System (ADS)

    Carpenter, J. R.

    1991-06-01

    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.

  4. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2008-02-01

    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.

  6. Comparing MHD simulations of RFP plasmas to RELAX experiments

    NASA Astrophysics Data System (ADS)

    McCollam, K. J.; den Hartog, D. J.; Jacobson, C. M.; Sauppe, J. P.; Masamune, S.; Sanpei, A.

    2015-11-01

    Standard reversed-field pinch (RFP) plasmas provide a nonlinear dynamical system as a validation domain for numerical MHD simulation codes, which can be applied to general toroidal confinement scenarios including tokamaks. Using the NIMROD code, we calculate linear stability and simulate the nonlinear evolution of plasmas similar to those in the RELAX RFP experiment, whose relatively modest Lundquist numbers of order 104 make the simulations tractable given present computing resources. The chosen RELAX cases cover a broad range of RFP reversal parameters and have also been previously simulated with the MIPS code (N. Mizuguchi et al., TH/P3-26, IAEA FEC, 2012). Experimental diagnostics that can be used for validation purposes include Thomson scattering for electron temperature, interferometry for electron density, SXR imaging, and external and internal magnetic probes. RELAX's small aspect ratio (~ 2) motivates a comparison study using toroidal and cylindrical geometries in NIMROD. This work is supported by the U.S. DOE and NSF and by the Japan Society for the Promotion of Science.

  7. Granular Solid-liquid Transition: Experiment and Simulation

    NASA Astrophysics Data System (ADS)

    Fei, M.; Xu, X.; Sun, Q.

    2015-12-01

    Granular media are amorphous materials, which differs from traditional solid or liquid. In different circumstance, granular behavior varies from solid-like to liquid-like, and the transitions between these regimes are always related to many complex natural progresses such as the failure of soil foundation and the occurrence of landslide and debris flow. The mechanic of elastic instability during the transition from solid-like to liquid-like regime, and the quantitative description of irreversible deformation during flow are the key problems to interpret these transition phenomena. In this work, we developed a continuum model with elastic stable condition and irreversible flow rule of granular material based on a thermal dynamical model, the Two-Granular-Temperature model (TGT). Since infinitesimal elastic deformation in solid-like regime and significant plastic large deformation in liquid-like regime can coexist in the granular solid-liquid transition process, the material point method (MPM) was used to build an effective numerical model. Collapse of rectangular granular pile contains both the transition from granular solid to granular liquid and the inverse process, thus in this work we carried out collapse experiment with clay particles, and simulated the experiment with our continuum model and an open-source DEM model YADE to study the transition processes. Results between experiment and simulations were compared and good agreements on collapse shape and velocity profiles were achieved, and the new model proposed in this work seems to work well on the description of granular solid-liquid transition.

  8. 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.

  9. 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.

  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. 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.

  12. 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.

  13. 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.

  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. Magnetohydrodynamic Simulation of Solid-Deuterium - Z-Pinch Experiments

    NASA Astrophysics Data System (ADS)

    Sheehey, Peter Trogdon

    Solid-deuterium-initiated Z-pinch experiments are numerically simulated using a two-dimensional resistive magnetohydrodynamic model, which includes many important experimental details, such as "cold-start" initial conditions, thermal conduction, radiative energy loss, actual discharge current vs. time, and grids of sufficient size and resolution to allow realistic development of the plasma. The alternating -direction-implicit numerical technique used meets the substantial demands presented by such a computational task. Simulations of fiber-initiated experiments show that when the fiber becomes fully ionized (at a time depending on current ramp and fiber thickness), rapidly developing m = 0 instabilities, which originated in the coronal plasma generated from the ablating fiber, drive intense non-uniform heating and rapid expansion of the plasma column. The possibility that inclusion of additional physical effects would improve stability is explored. Finite-Larmor-radius-ordered Hall and diamagnetic pressure terms in the magnetic field evolution equation, corresponding energy equation terms, and separate ion and electron energy equations are included; these do not change the basic results. Model diagnostics, such as shadowgrams and interferograms, generated from simulation results, are in good agreement with experiment. Two alternative experimental approaches are explored: high-current magnetic implosion of hollow cylindrical deuterium shells, and "plasma -on wire" (POW) implosion of low-density plasma onto a central deuterium fiber. By minimizing instability problems, these techniques may allow attainment of higher temperatures and densities than possible with bare fiber-initiated Z -pinches. Conditions for significant D-D or D-T fusion neutron production may be realizable with these implosion -based approaches.

  16. One-dimensional hydrodynamic simulation of high energy density experiments

    NASA Astrophysics Data System (ADS)

    Grinenko, A.

    2009-07-01

    A new one-dimensional hydrodynamic code for simulation of experiments involving the creation of high energy density in matter by means of laser or heavy ion beam irradiation is described. The code uses well-tested second order Lagrangian scheme in combination with the flux-limited van Leer convection algorithm for re-mapping to an arbitrary grid. Simple test cases with self-similar solutions are examined. Finally, the heating of solid targets by lasers and ions beams is investigated as examples.

  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. 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

  19. Simulations of Ion Coupling Experiments on NDCX-II relevant to IFE

    NASA Astrophysics Data System (ADS)

    Barnard, J. J.; More, R. M.; Terry, M.

    2012-10-01

    The Neutralized Drift Compression Experiment II (NDCX-II) is an induction accelerator for which the construction project was completed at Lawrence Berkeley National Laboratory in March, 2012, and is presently being commissioned. The baseline design for NDCX-II will accelerate ˜0.03 μC of singly charged lithium ions to 1.2 MeV (with possible upgrades up to 3.1 MeV), delivered in sub-ns pulses with sub-mm rms beam radii. The purpose of NDCX-II is to carry out beam and target interaction experiments relevant to IFE. We have carried out detailed hydrodynamic simulations of planar targets having several configurations. In this poster we will focus on experiments that maximize shock strength by traveling wave deposition (i.e. by varying ion beam energy in a velocity chirp) and/or by varying intensity profile, and we will also explore methods to optimize shock strengths in composite materials where shocks can be formed at material boundaries and at end-of-range. These results will be discussed in the context of heavy ion fusion direct drive targets.

  20. Simulation for Proton Charge Radius (PRad) Experiment at Jefferson Lab

    NASA Astrophysics Data System (ADS)

    Ye, Li; PRad Collaboration Collaboration

    2016-09-01

    The ``Proton Charge Radius Puzzle'' refers to 7 σ discrepancy between the proton charge radius extracted from muonic hydrogen Lamb shift measurements and that from the atomic hydrogen Lamb shift and e-p elastic scattering measurements. In order to get a better understanding of this puzzle, the PRad experiment (E12-11-106) was proposed and recently performed with 1.1 and 2.2 GeV unpolarized electron beam in Hall B at Jefferson Lab. The experiment aims to extract the electric form factor and the charge radius of proton by simultaneously measuring the e - p elastic scattering cross section and the Møller cross section at very low Q2(2 × 10-4 10-1(GeV / c) 2) region, with sub-percent precision. A windowless hydrogen gas flow target was used to better control the background. A high-efficiency and high-resolution calorimeter (HyCal) and a pair of Gas Electron Multiplier (GEM) chambers were used in the experiment. This talk will focus on comparing the detailed simulation of PRad experiment and its background with preliminary spectra from the data. This work is supported in part by NSF MRI Award PHY-1229153, the U.S. Department of Energy under Contacts No. DE-FG02-07ER41528, Thomas Jefferson National Laboratory, Mississippi State University and PRad collaboration.

  1. Integrated P1 Hohlraum/Capsule Simulations for NIF Experiments

    NASA Astrophysics Data System (ADS)

    Eder, David; Spears, Brian; Town, Richard; Jones, Oggie; Ma, Tammy; Pak, Arthur; Benedetti, Robin; Hatchett, Steve; Knauer, James; MacKinnon, Andrew; Yeamans, Charles; McNaney, James; Casey, Daniel

    2014-10-01

    We discuss integrated hohlraum/capsule post-shot simulations of two full-scale cryogenic NIF experiments that drove a DT symcap capsule downward/upward by having the peak power in the upper laser beams 16% greater/less than the lower beams. This laser asymmetry results in a radiation drive P1/P0 at the capsule ablation surface of ~2% and a downward/upward capsule velocity of order 100 microns/ns in agreement with the data. The experimental velocity is determined by comparing measurements at different locations of both the arrival times of DD and DT neutrons at time-of-flight detectors, and by zirconium activation measurements that are a function of neutron energy. We compare these two shots to a control shot for the same target with no specified laser asymmetries. We also discuss simulations of planned sub-scale warm symcap experiments that have a goal of measuring DT and DD ion temperatures and the electron temperature as a function of the imposed P1 to characterize the role of non-thermal velocity on temperature measurements. This work performed under the auspices of the U.S. Department of Energy by LLNL under Contract DE-AC52-07NA27344. LLNL-ABS-656659.

  2. The LHCb Simulation Application, Gauss: Design, Evolution and Experience

    NASA Astrophysics Data System (ADS)

    Clemencic, M.; Corti, G.; Easo, S.; Jones, C. R.; Miglioranzi, S.; Pappagallo, M.; Robbe, P.; LHCb Collaboration

    2011-12-01

    The LHCb simulation application, Gauss, is based on the Gaudi framework and on experiment basic components such as the Event Model and Detector Description. Gauss also depends on external libraries for the generation of the primary events (PYTHIA 6, EvtGen, etc.) and on GEANT4 for particle transport in the experimental setup. The application supports the production of different types of events from minimum bias to B physics signals and particle guns. It is used for purely generator-level studies as well as full simulations. Gauss is used both directly by users and in massive central productions on the grid. The design and implementation of the application and its evolution due to evolving requirements will be described as in the case of the recently adopted Python-based configuration or the possibility of taking into account detectors conditions via a Simulation Conditions database. The challenge of supporting at the same time the flexibililty needed for the different tasks for which it is used, from evaluation of physics reach to background modeling, together with the stability and reliabilty of the code will also be described.

  3. 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.

  4. 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.

  5. 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.

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

    PubMed

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

    2011-04-07

    In this paper we examine the phase behavior of the Weeks-Chandler-Andersen (WCA) potential with βε = 40. Crystal nucleation in this model system was recently studied by Kawasaki and Tanaka [Proc. Natl. Acad. Sci. U.S.A. 107, 14036 (2010)], 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); S. Auer and D. Frenkel, Nature 409, 1020 (2001)].

  7. 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

  8. 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

  9. Neutron Transport Simulations for NIST Neutron Lifetime Experiment

    NASA Astrophysics Data System (ADS)

    Li, Fangchen; BL2 Collaboration Collaboration

    2016-09-01

    Neutrons in stable nuclei can exist forever; a free neutron lasts for about 15 minutes on average before it beta decays to a proton, an electron, and an antineutrino. Precision measurements of the neutron lifetime test the validity of weak interaction theory and provide input into the theory of the evolution of light elements in the early universe. There are two predominant ways of measuring the neutron lifetime: the bottle method and the beam method. The bottle method measures decays of ultracold neutrons that are stored in a bottle. The beam method measures decay protons in a beam of cold neutrons of known flux. An improved beam experiment is being prepared at the National Institute of Science and Technology (Gaithersburg, MD) with the goal of reducing statistical and systematic uncertainties to the level of 1 s. The purpose of my studies was to develop computer simulations of neutron transport to determine the beam collimation and study the neutron distribution's effect on systematic effects for the experiment, such as the solid angle of the neutron flux monitor. The motivation for the experiment and the results of this work will be presented. This work was supported, in part, by a Grant to Gettysburg College from the Howard Hughes Medical Institute through the Precollege and Undergraduate Science Education Program.

  10. Simulation of Extreme Arctic Cyclones in IPCC AR5 Experiments

    NASA Astrophysics Data System (ADS)

    Vavrus, S. J.

    2012-12-01

    Although impending Arctic climate change is widely recognized, a wild card in its expression is how extreme weather events in this region will respond to greenhouse warming. Intense polar cyclones represent one type of high-latitude phenomena falling into this category, including very deep synoptic-scale cyclones and mesoscale polar lows. These systems inflict damage through high winds, heavy precipitation, and wave action along coastlines, and their impact is expected to expand in the future, when reduced sea ice cover allows enhanced wave energy. The loss of a buffering ice pack could greatly increase the rate of coastal erosion, which has already been increasing in the Arctic. These and related threats may amplify if extreme Arctic cyclones become more frequent and/or intense in a warming climate with much more open water to fuel them. This possibility has merit on the basis of GCM experiments, which project that greenhouse forcing causes lower mean sea level pressure (SLP) in the Arctic and a strengthening of the deepest storms over boreal high latitudes. In this study, the latest Coupled Model Intercomparison Project (CMIP5) climate model output is used to investigate the following questions: (1) What are the spatial and seasonal characteristics of extreme Arctic cyclones? (2) How well do GCMs simulate these phenomena? (3) Are Arctic cyclones already showing the expected response to greenhouse warming in climate models? To address these questions, a retrospective analysis is conducted of the transient 20th century simulations among the CMIP5 GCMs (spanning years 1850-2005). The results demonstrate that GCMs are able to reasonably represent extreme Arctic cyclones and that the simulated characteristics do not depend significantly on model resolution. Consistent with observational evidence, climate models generate these storms primarily during winter and within the climatological Aleutian and Icelandic Low regions. Occasionally the cyclones remain very intense

  11. 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.

  12. 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.

  13. 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.

  14. Aerodynamics of ski jumping: experiments and CFD simulations

    NASA Astrophysics Data System (ADS)

    Meile, W.; Reisenberger, E.; Mayer, M.; Schmölzer, B.; Müller, W.; Brenn, G.

    2006-12-01

    The aerodynamic behaviour of a model ski jumper is investigated experimentally at full-scale Reynolds numbers and computationally applying a standard RANS code. In particular we focus on the influence of different postures on aerodynamic forces in a wide range of angles of attack. The experimental results proved to be in good agreement with full-scale measurements with athletes in much larger wind tunnels, and form a reliable basis for further predictions of the effects of position changes on the performance. The comparison of CFD results with the experiments shows poor agreement, but enables a clear outline of simulation potentials and limits when accurate predictions of effects from small variations are required.

  15. Movement of patches during thermoforming: Experiment and simulation

    NASA Astrophysics Data System (ADS)

    Schell, J. S. U.; Amory, L.; Guillon, D.

    2016-10-01

    The application of local reinforcement like uni-directional patches can locally increase the strength of composite parts without adding much weight. During design through structural analysis, shape and position of local reinforcement can easily be determined. In the thermoforming process, patches can be integrated into the ply-stack by preassembling. During forming, these patches can move and change their position reducing the structural effect of the patch. The movement of patches has been investigated experimentally. Key factors that influence this movement are orientation, size, position in the pile and slope of the mold. The forming process is simulated using HYPERFORM. The results show that this complex process needs special models which can be computationally intensive. In this work, we model the movement of patches and compare with experiments. The final goal is to have a reasonable predictive capability for movement of patches and design the process to minimize it.

  16. 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.

  17. 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.

  18. 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).

  19. Parallel collisionless shocks forming in simulations of the LAPD experiment

    NASA Astrophysics Data System (ADS)

    Weidl, Martin S.; Jenko, Frank; Niemann, Chris; Winske, Dan

    2016-10-01

    Research on parallel collisionless shocks, most prominently occurring in the Earth's bow shock region, has so far been limited to satellite measurements and simulations. However, the formation of collisionless shocks depends on a wide range of parameters and scales, which can be accessed more easily in a laboratory experiment. Using a kJ-class laser, an ongoing experimental campaign at the Large Plasma Device (LAPD) at UCLA is expected to produce the first laboratory measurements of the formation of a parallel collisionless shock. We present hybrid kinetic/MHD simulations that show how beam instabilities in the background plasma can be driven by ablating carbon ions from a target, causing non-linear density oscillations which develop into a propagating shock front. The free-streaming carbon ions can excite both the resonant right-hand instability and the non-resonant firehose mode. We analyze their respective roles and discuss optimizing their growth rates to speed up the process of shock formation.

  20. 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.

  1. Visualizing simulated learning experiences through the use of informatics tools.

    PubMed

    Thompson, Teri L; Warren, Judith J

    2009-01-01

    High-fidelity simulation technology is a growing educational technology. Designing effective simulations requires the use of informatics tools such as UML modeling. This poster demonstrates the steps in modeling a simulation exercise.

  2. 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.

  3. 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.

  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. Conceptual Issues in Quantifying Unusualness and Conceiving Stochastic Experiments: Insights from Students' Experiences in Designing Sampling Simulations

    ERIC Educational Resources Information Center

    Saldanha, Luis

    2016-01-01

    This article reports on a classroom teaching experiment that engaged a group of high school students in designing sampling simulations within a computer microworld. The simulation-design activities aimed to foster students' abilities to conceive of contextual situations as stochastic experiments, and to engage them with the logic of hypothesis…

  6. 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

  7. Developing RESRAD-BASELINE for environmental baseline risk assessment

    SciTech Connect

    Cheng, Jing-Jy

    1995-12-31

    RESRAD-BASELINE is a computer code developed at Argonne developed at Argonne National Laboratory for the US Department of Energy (DOE) to perform both radiological and chemical risk assessments. The code implements the baseline risk assessment guidance of the US Environmental Protection Agency (EPA 1989). The computer code calculates (1) radiation doses and cancer risks from exposure to radioactive materials, and (2) hazard indexes and cancer risks from exposure to noncarcinogenic and carcinogenic chemicals, respectively. The user can enter measured or predicted environmental media concentrations from the graphic interface and can simulate different exposure scenarios by selecting the appropriate pathways and modifying the exposure parameters. The database used by PESRAD-BASELINE includes dose conversion factors and slope factors for radionuclides and toxicity information and properties for chemicals. The user can modify the database for use in the calculation. Sensitivity analysis can be performed while running the computer code to examine the influence of the input parameters. Use of RESRAD-BASELINE for risk analysis is easy, fast, and cost-saving. Furthermore, it ensures in consistency in methodology for both radiological and chemical risk analyses.

  8. Simulation of astrophysical jets in a laboratory experiment

    NASA Astrophysics Data System (ADS)

    Bellan, Paul

    2006-04-01

    Astrophysical jets are routinely simulated in a reproducible, well-diagnosed laboratory experiment. The experimental sequence starts by imposing a vacuum poloidal magnetic field linking a disk electrode to a co-planar annular electrode. Neutral gas (H, Ne, N, or Ar) is then injected via 8 nozzles located on the disk and 8 nozzles on the annulus. A 120 μF capacitor bank power supply charged to 4-7 kV is applied via ignitron switches across the electrodes, breaking down the injected gas to form plasma. The low impedance (<10 mφ) of the highly conducting plasma causes the power supply to behave as a current source, rather than a voltage source. The discharging capacitor bank drives a ˜100 kA poloidal electric current through the plasma; this current initially flows in eight distinct `spider legs' (see photo in April meeting poster) that span from the disk to the annulus. The spider legs quickly merge via mutual attraction of their currents to form the simulated astrophysical jet. The axial gradient of the toroidal magnetic field energy density provides the force that accelerates the jet. The mass flux boundary condition at the electrodes is tightly coupled to the jet behavior. The jet is `fueled' by plasma ingested from the nozzles and the accumulation (pile-up) of the ingested plasma collimates the jet because of the associated pile-up of frozen-in toroidal magnetic flux convected with the plasma. The jet undergoes a kink instability when it becomes long enough to satisfy the Kruskal-Shafranov q=1 condition.

  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. 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.

  12. Localized harmonic motion imaging: theory, simulations and experiments.

    PubMed

    Konofagou, Elisa E; Hynynen, Kullervo

    2003-10-01

    Several techniques have been developed in an effort to estimate mechanical properties of tissues. These techniques typically estimate static or harmonic motion resulting from an externally or internally applied mechanical stimulus. In this paper, we discuss the advantages of utilizing a new technique that performs radiofrequency (RF) signal tracking to estimate the localized oscillatory motion resulting from the harmonic radiation force produced by two focused ultrasound (US) transducer elements with overlapping beams oscillating at distinct frequencies. Finite-element and Monte-Carlo simulations were performed to characterize the range of oscillatory displacements produced by a harmonic radiation force. In the experimental verification, three transducers were used: two single-element focused transducers and one lead zirconate-titanate (PZT) composite 16-element probe. Four agar gels were utilized to determine the effect of stiffness on the motion amplitude. Estimates of the displacement relative to the initial position (i.e., at the onset of the application of the radiation force) were obtained during the application of the radiation force that oscillated at frequencies ranging between 200 Hz and 800 Hz. In the simulations, the estimated oscillatory displacement spanned from -800 to 600 microm and the frequencies of excitation could easily be estimated from the temporal variation of the displacement. In addition, a frequency upshift (on the order of tens of Hz) was estimated with stiffness increase. Furthermore, an exponential decrease of the displacement amplitude with stiffness was observed at all frequencies investigated. An M-mode version to depict both the spatial and temporal variations of the locally induced displacement was used. In experiments with gels of different stiffness, the resulting amplitude of the harmonic displacement estimated oscillated at the same frequencies and ranged from -300 to 250 microm. An exponential decrease of the displacement

  13. 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.

  14. 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.

  15. 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.

  16. 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

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

    PubMed

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

    2015-09-15

    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.

  18. On the consistency of scale among experiments, theory, and simulation

    NASA Astrophysics Data System (ADS)

    McClure, James E.; Dye, Amanda L.; Miller, Cass T.; Gray, William G.

    2017-02-01

    As a tool for addressing problems of scale, we consider an evolving approach known as the thermodynamically constrained averaging theory (TCAT), which has broad applicability to hydrology. We consider the case of modeling of two-fluid-phase flow in porous media, and we focus on issues of scale as they relate to various measures of pressure, capillary pressure, and state equations needed to produce solvable models. We apply TCAT to perform physics-based data assimilation to understand how the internal behavior influences the macroscale state of two-fluid porous medium systems. A microfluidic experimental method and a lattice Boltzmann simulation method are used to examine a key deficiency associated with standard approaches. In a hydrologic process such as evaporation, the water content will ultimately be reduced below the irreducible wetting-phase saturation determined from experiments. This is problematic since the derived closure relationships cannot predict the associated capillary pressures for these states. We demonstrate that the irreducible wetting-phase saturation is an artifact of the experimental design, caused by the fact that the boundary pressure difference does not approximate the true capillary pressure. Using averaging methods, we compute the true capillary pressure for fluid configurations at and below the irreducible wetting-phase saturation. Results of our analysis include a state function for the capillary pressure expressed as a function of fluid saturation and interfacial area.

  19. On the consistency of scale among experiments, theory, and simulation

    DOE PAGES

    McClure, James E.; Dye, Amanda L.; Miller, Cass T.; ...

    2017-02-20

    As a tool for addressing problems of scale, we consider an evolving approach known as the thermodynamically constrained averaging theory (TCAT), which has broad applicability to hydrology. We consider the case of modeling of two-fluid-phase flow in porous media, and we focus on issues of scale as they relate to various measures of pressure, capillary pressure, and state equations needed to produce solvable models. We apply TCAT to perform physics-based data assimilation to understand how the internal behavior influences the macroscale state of two-fluid porous medium systems. A microfluidic experimental method and a lattice Boltzmann simulation method are used to examinemore » a key deficiency associated with standard approaches. In a hydrologic process such as evaporation, the water content will ultimately be reduced below the irreducible wetting-phase saturation determined from experiments. This is problematic since the derived closure relationships cannot predict the associated capillary pressures for these states. We demonstrate that the irreducible wetting-phase saturation is an artifact of the experimental design, caused by the fact that the boundary pressure difference does not approximate the true capillary pressure. Using averaging methods, we compute the true capillary pressure for fluid configurations at and below the irreducible wetting-phase saturation. Results of our analysis include a state function for the capillary pressure expressed as a function of fluid saturation and interfacial area.« less

  20. Solution structures of rat amylin peptide: simulation, theory, and experiment.

    PubMed

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

    2010-02-03

    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 alpha-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 alpha-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.

  1. Fluorescence correlation spectroscopy of repulsive systems: theory, simulation, and experiment.

    PubMed

    Feng, Ligang; Yang, Jingfa; Zhao, Jiang; Wang, Dapeng; Koynov, Kaloian; Butt, Hans-Jürgen

    2013-06-07

    The theoretical basis of fluorescence correlation spectroscopy (FCS) for repulsive systems, such as charged colloids or macromolecules, has been further expanded and developed. It is established that the collective correlation function can no longer be fitted using the theoretical model of non-interacting systems. Also, it is discovered that the collective correlation function can be divided into two parts: a self-part and a distinct-part, named as the self-correlation and cross-correlation function, respectively. The former indicates the self-diffusion of objects, while the latter describes mutual interactions. Dual-color fluorescence cross-correlation spectroscopy provides the direct measurements of the two parts. The particle concentration and mean squared displacement of single particles can be deduced from the self-correlation function, while the correlation volume between particles can be approximated from the cross-correlation function. In the case of charged colloids, the Debye length of the solution and particle surface charge number can be fitted from the cross-correlation function. These theoretical results are successfully proven using Brownian dynamics simulations and preliminary FCS experiments for model charged colloidal systems.

  2. Experiments and simulations of RT and RM fronts

    NASA Astrophysics Data System (ADS)

    Lopez, P.; Gushkov, S.

    2009-04-01

    Experimental and numerical results on the advance of a mixing or non-mixing front occurring at a density interface due to gravitational acceleration are analyzed considering the fractal and spectral structure of the front. The experimental configuration consists on a unstable two layer system held by a removable plate in a box for the Rayleigh-Taylor fronts and shock tube high Mach number impulse across a density interface air/SF6. The evolution of the turbulent mixing layer and its complex configuration is studied taking into account the dependence on the initial modes at the early stages and its spectral, self-similar information. Most models of the turbulent mixing evolution generated by hydrodynamics instabilities do not include any dependence on initial conditions, but in many relevant physical problems this dependence is very important, for instance, in Inertial Confinement Fussion target implosion. We discuss simple initial conditions (such as a jet array versus a plate removal) with the aid of numerical models. The analysis of Kelvin-Helmholtz, Rayleigh-Taylor, Richtmyer-Meshkov and of accelerated instabilities is presented locally, and seen to dominate the turbulent cascade mixing zone differently under different initial conditions. Fractal and neuron network analysis of Turbulent Mixing under RT and RM instabilities are presented comparing the different experiments and numerical simulations.

  3. 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

  4. 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

  5. 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.

  6. FAQs about Baseline Testing among Young Athletes

    MedlinePlus

    ... and reaction time. During the baseline pre-season test, health care professionals should also assess for a prior history ... tests should only be conducted by a trained health care professional. Who should interpret baseline tests? Only a trained health care professional with experience ...

  7. The Lived-Experience of Novice Nurse's Actualizing Clinical Reasoning in Academic Simulation

    ERIC Educational Resources Information Center

    Brinker, Mary Catherine

    2016-01-01

    The purpose of this existential-phenomenological study was to address the first-person perspective of what it is like to experience clinical reasoning during a simulation. It was not known how a novice nurse would describe the experience of actualizing clinical reasoning during the academic simulation experience. In order to maintain the…

  8. Laboratory Simulations Of Titan’s Atmospheric Chemistry With The NASA Ames Titan Haze Simulation Experiment

    NASA Astrophysics Data System (ADS)

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

    2012-05-01

    Solar UV radiation and electron bombardment from Saturn’s magnetosphere dissociate nitrogen and methane in Titan’s atmosphere, leading to the production of heavier molecules and solid organic aerosols that contribute to the haze layers giving Titan its characteristic orange color. The detection of benzene and toluene, critical precursors of polycyclic aromatic hydrocarbon (PAH), in Titan’s ionosphere, by the Cassini INMS 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 molecules resulting from the first steps of the N2-CH4 chemistry (C2H2, C2H4, HCN..) to benzene, and to PAHs and nitrogen-containing PAHs (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 Cavity Ring Down Spectroscopy and Time-Of-Flight Mass Spectrometry. Thin tholin (Titan aerosol analogs) 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 present the results of mass spectrometry studies using different gas mixtures, and discuss their relevance for the study of specific pathways in Titan’s atmospheric chemistry. Acknowledgements: This research is supported by NASA PATM. E.S.O., C.S.C. and C.L.R acknowledge the support of the NASA Postdoctoral Program. The authors acknowledge the

  9. Observation system simulation experiments using water vapor isotope information

    NASA Astrophysics Data System (ADS)

    Yoshimura, Kei; Miyoshi, Takemasa; Kanamitsu, Masao

    2014-07-01

    Measurements of water vapor isotopes (δ18O and δD) have dramatically increased in recent years with the availability of new spectroscopic technology. To utilize these data more efficiently, this study first developed a new data assimilation system using a local transform ensemble Kalman filter (LETKF) and the Isotope-incorporated Global Spectral Model (IsoGSM). An observation system simulation experiment (OSSE) was then conducted. The OSSE used a synthetic data set of vapor isotope measurements, mimicking Tropospheric Emission Spectrometer (TES)-retrieved δD from the mid-troposphere, SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY (SCIAMACHY)-retrieved δD from the water vapor column, and the virtual Global Network of Isotopes in Precipitation (GNIP)-like surface vapor isotope (both δD and δ18O) monitoring network. For TES and SCIAMACHY, we assumed a similar spatiotemporal coverage as that of the real data sets. For the virtual GNIP-like network, we assumed ~200 sites worldwide and 6-hourly measurements. An OSSE with 20 ensemble members was then conducted for January 2006. The results showed a significant improvement in not only the vapor isotopic field but also meteorological fields, such as wind speed, temperature, surface pressure, and humidity, when compared with a test with no observations. For surface air temperature, the global root mean square error has dropped by 10%, with 40-60% of the decrease occurring in the east-southeast Asia where the concentration of observations is relatively higher. When there is a conventional radiosonde network, the improvement gained by adding isotopic measurements was small but positive for all variables.

  10. Simulation-guided cardiac auscultation improves medical students' clinical skills: the Pavia pilot experience.

    PubMed

    Perlini, Stefano; Salinaro, Francesco; Santalucia, Paola; Musca, Francesco

    2014-03-01

    Clinical evaluation is the cornerstone of any cardiac diagnosis, although excessive over-specialisation often leads students to disregard the value of clinical skills, and to overemphasize the approach to instrumental cardiac diagnosis. Time restraints, low availability of "typical" cardiac patients on whom to perform effective bedside teaching, patients' respect and the underscoring of the value of clinical skills all lead to a progressive decay in teaching. Simulation-guided cardiac auscultation may improve clinical training in medical students and residents. Harvey(©) is a mannequin encompassing more than 50 cardiac diagnoses that was designed and developed at the University of Miami (Florida, USA). One of the advantages of Harvey(©) simulation resides in the possibility of listening, comparing and discussing "real" murmurs. To objectively assess its teaching performance, the capability to identify five different cardiac diagnoses (atrial septal defect, normal young subject, mitral stenosis with tricuspid regurgitation, chronic mitral regurgitation, and pericarditis) out of more than 50 diagnostic possibilities was assessed in 523 III-year medical students (i.e. at the very beginning of their clinical experience), in 92 VI-year students, and in 42 residents before and after a formal 10-h teaching session with Harvey(©). None of them had previously experienced simulation-based cardiac auscultation in addition to formal lecturing (all three groups) and bedside teaching (VI-year students and residents). In order to assess the "persistence" of the acquired knowledge over time, the test was repeated after 3 years in 85 students, who did not repeat the formal 10-h teaching session with Harvey(©) after the III year. As expected, the overall response was poor in the "beginners" who correctly identified 11.0 % of the administered cardiac murmurs. After simulation-guided training, the ability to recognise the correct cardiac diagnoses was much better (72.0 %; p < 0

  11. 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.

  12. 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

  13. The Impact of Goal Setting on Team Simulation Experience.

    ERIC Educational Resources Information Center

    Fandt, Patricia M.; And Others

    1990-01-01

    Describes a study that examined the effects of goal setting on undergraduate students competing in a computerized business simulation. Group cohesiveness is discussed, treatments for the experimental and control groups are described, perceived team success is measured, and team simulation performance is evaluated. (30 references) (LRW)

  14. Accelerated Laboratory Research Experience in Psychology through Simulation.

    ERIC Educational Resources Information Center

    Chatfield, Douglas C.; Cruse, Bradley H.

    1986-01-01

    Describes implementation of computer simulation to aid in training psychology students in research methodology. Four skills required in research are reviewed; the simulation's context and the software used are described; and student activities, including submission of articles to online class journals and students' responses to the method, are…

  15. 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

  16. 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

  17. Sequentially Simulated Outcomes: Kind Experience versus Nontransparent Description

    ERIC Educational Resources Information Center

    Hogarth, Robin M.; Soyer, Emre

    2011-01-01

    Recently, researchers have investigated differences in decision making based on description and experience. We address the issue of when experience-based judgments of probability are more accurate than are those based on description. If description is well understood ("transparent") and experience is misleading ("wicked"), it…

  18. Observation System Simulation Experiment (OSSE) using water vapor isotopes

    NASA Astrophysics Data System (ADS)

    Yoshimura, K.

    2013-12-01

    Measurements of water vapor isotopes (δ18O and δD) have been drastically increased these years with new technology, i.e., spectroscopic instruments both satellite-onboard and ground-based (in-situ) to improve our understanding of the hydrologic cycle in the atmosphere and land surface. To more efficiently utilize these data, this study first developed a new data assimilation system with Local Transform Ensemble Kalman Filter (LETKF) and Isotope-incorporated Global Spectral Model (IsoGSM). Then an observation system simulation experiment (OSSE) was conducted. This OSSE uses a mock dataset of vapor isotope measurements, namely TES/Aura retrieved δD at mid-troposphere, SCIAMACHY/Envisat retrieved δD at vapor column, and virtual GNIP-like vapor isotope (both δD and δ18O) monitoring network. We used historical retrieval numbers for TES and SCIAMACHY measurements, which are 15,000 and 10,000 data in January 2006. For virtual GNIP-like network, we assumed about 200 sites over the world, and 6-hourly measurement at 2m from surface. The accuracy of the measurements are 10‰ and 100‰ for δ18O and δD, respectively, including the uncertainty associated with representativeness of the data in space and time. Then the OSSE with 20 ensemble member was conducted for January 2006. The results are indeed remarkable. It showed significant improvement in not only vapor isotopic field but also meteorological fields, such as wind speed, temperature, surface pressure and humidity, comparing with a test without any observation. For surface air temperature, the global RMSE has dropped 10%, in which as large as 40-60% decrease is observed in east-southeast Asia area where the observation concentration is relatively higher. Most of the variables showed consistently similar feature. These results clearly show that the vapor isotope measurement definitely help to improve our understanding of hydrologic cycle through constraining with the data assimilation. RMSE of 6-hourly data for 2

  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. Optical Long Baseline Interferometry

    NASA Astrophysics Data System (ADS)

    Le Bouquin, Jean-Baptiste

    Optical Long Baseline Interferometry provides unrivalled angular resolution on bright and compact astrophysical sources. The link between the observables (interferometric phase and contrast) and the image of the source is a Fourier transform expressed first by van Cittert and Zernike. Depending on the source size and the amount of information collected, the analysis of these Fourier components allows a measurement of the typical source size, a parametric modelling of its spatial structures, or a model-independent image reconstruction to be carried. In the past decades, optical long baseline interferometry provided fundamental measurements for astronomy (ex. Cepheids distances, surface-brightness relations) as well as iconic results such as the first images of stellar surfaces other than the Sun. Optical long baseline interferometers exist in the Northern and Southern hemisphere and are open to the astronomical community with modern level of support. We provide in this chapter an introduction to the fundamental principles of optical interferometry and introduce the currently available facilities.

  1. Simulation of Extreme Arctic Cyclones in IPCC AR5 Experiments

    DTIC Science & Technology

    2012-09-30

    of the current generation of global climate models (GCMs) to simulate extreme Arctic cyclones and identify changes in the characteristics of these...2011). 5. The CCSM4 simulations show an interesting shift in the location of extreme Arctic cyclones as a function of greenhouse warming (Figure 1...preferred track over the North Atlantic-Barents Sea. However, this change is not effected by the modest greenhouse warming between 1850-2000, when

  2. Simulation of Extreme Arctic Cyclones in IPCC AR5 Experiments

    DTIC Science & Technology

    2014-05-15

    cyclones and identify changes in the characteristics of these storms caused by greenhouse -forced climate change to present. OBJECTIVES These goals...How well do state-of-the-art GCMs simulate them? (3) Are extreme Arctic cyclones already showing a response to greenhouse forcing? APPROACH These...study used 14 GCMs with widely varying horizontal and vertical resolutions and physics packages. These simulations were compared with an atmospheric

  3. 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.

  4. Modeling Baseline Shifts in Multivariate Disease Outbreak Detection

    PubMed Central

    Que, Jialan; Tsui, Fu-Chiang

    2013-01-01

    Objective Outbreak detection algorithms monitoring only disease-relevant data streams may be prone to false alarms due to baseline shifts. In this paper, we propose a Multinomial-Generalized-Dirichlet (MGD) model to adjust for baseline shifts. Introduction Population surges or large events may cause shift of data collected by biosurveillance systems [1]. For example, the Cherry Blossom Festival brings hundreds of thousands of people to DC every year, which results in simultaneous elevations in multiple data streams (Fig. 1). In this paper, we propose an MGD model to accommodate the needs of dealing with baseline shifts. Methods Existing multivariate algorithms only model disease-relevant data streams (e.g., anti-fever medication sales or patient visits with constitutional syndrome for detection of flu outbreak). On the contrary, we also incorporate a non-disease-relevant data stream as a control factor. We assume that the counts from all data streams follow a Multinomial distribution. Given this distribution, the expected value of the distribution parameter is not subject to change during a baseline shift; however, it has to change in order to model an outbreak. Therefore, this distribution inherently adjusts for the baseline shifts. In addition, we use the generalized Dirichlet (GD) distribution to model the parameter, since GD distribution is one of the conjugate prior of Multinomial [2]. We call this model the Multinomial-Generalized-Dirichlet (MGD) model. Results We applied MGD model in our previous proposed Rank-Based Spatial Clustering (MRSC) algorithm [3]. We simulated both outbreak cases and baseline shift phenomena. The experiment includes two groups of data sets. The first includes the data sets only injected with outbreak cases, and the second includes the ones with both outbreak cases and baseline shifts. We apply MRSC algorithm and a reference method, the Multivariate Bayesian Scan Statistic (MBSS) algorithm (which only analyzes the disease

  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. 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…

  7. 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…

  8. 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.

  9. Agricultural Baseline (BL0) scenario

    SciTech Connect

    Davis, Maggie R.; Hellwinckel, Chad M; Eaton, Laurence; Turhollow, Anthony; Brandt, Craig; Langholtz, Matthew H.

    2016-07-13

    Scientific reason for data generation: to serve as the reference case for the BT16 volume 1 agricultural scenarios. The agricultural baseline runs from 2015 through 2040; a starting year of 2014 is used. Date the data set was last modified: 02/12/2016 How each parameter was produced (methods), format, and relationship to other data in the data set: simulation was developed without offering a farmgate price to energy crops or residues (i.e., building on both the USDA 2015 baseline and the agricultural census data (USDA NASS 2014). Data generated are .txt output files by year, simulation identifier, county code (1-3109). Instruments used: POLYSYS (version POLYS2015_V10_alt_JAN22B) supplied by the University of Tennessee APAC The quality assurance and quality control that have been applied: • Check for negative planted area, harvested area, production, yield and cost values. • Check if harvested area exceeds planted area for annuals. • Check FIPS codes.

  10. 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.

  11. 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.

  12. Simulations and experiments on RITA-2 at PSI

    NASA Astrophysics Data System (ADS)

    Klausen, S. N.; Lefmann, K.; McMorrow, D. F.; Altorfer, F.; Janssen, S.; Lüthy, M.

    The cold-neutron triple-axis spectrometer RITA-2 designed and built at Riso National Laboratory was installed at the neutron source SINQ at Paul Scherrer Institute in April/May 2001. In connection with the installation of RITA-2, computer simulations were performed using the neutron ray-tracing package McStas. The simulation results are compared to real experimental results obtained with a powder sample. Especially, the flux at the sample position and the resolution function of the spectrometer are investigated.

  13. Gold-Palladium core@shell nanoalloys: experiments and simulations

    PubMed Central

    Spitale, A.; Perez, M. A.; Mejía-Rosales, S.; Yacamán, M. J.

    2015-01-01

    In this work, we report a facile synthesis route, structural characterization, and full atomistic simulations of gold-palladium nanoalloys. Through aberration corrected-STEM, UV-vis and EDS chemical analysis, we were able to determine that Au(core)-Pd(shell) bimetallic nanoparticles were formed. Using different computational approaches, we were capable to establish how the size of the core and the thickness of the shell will affect the thermodynamic stability of several core-shell nanoalloys. Finally, grand canonical simulations using different sampling procedures were used to study the growth mechanism of Pd atoms on Au seeds of different shape. PMID:25735727

  14. 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.

  15. 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

  16. Gold-palladium core@shell nanoalloys: experiments and simulations.

    PubMed

    Spitale, A; Perez, M A; Mejía-Rosales, S; Yacamán, M J; Mariscal, M M

    2015-11-14

    In this work, we report a facile synthesis route, structural characterization, and full atomistic simulations of gold-palladium nanoalloys. Through aberration corrected-STEM, UV-vis spectroscopy and EDS chemical analysis, we were able to determine that Au(core)-Pd(shell) bimetallic nanoparticles were formed. Using different computational approaches, we were capable of establishing how the size of the core and the thickness of the shell will affect the thermodynamic stability of several core-shell nanoalloys. Finally, grand canonical simulations using different sampling procedures were used to study the growth mechanism of Pd atoms on Au seeds of different shapes.

  17. 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.

  18. Group Size and Attitudes toward the Simulation Experience.

    ERIC Educational Resources Information Center

    Gentry, James W.

    1980-01-01

    A study to determine whether a relationship existed between team size and various attitudinal and performance variables in simulation games played by undergraduate business students indicated that group size had no impact on the group's performance, but that it was strongly related to the amount of dissension in the group. (LLS)

  19. Critical Incidents in Counseling: Simulated Video Experiences for Training Counselors

    ERIC Educational Resources Information Center

    Spivack, James D.

    1973-01-01

    This article explains the rationale, development, and use of a simulation approach to training counselors in which videotaped vignettes of critical incidents that occur in the course of establishing and maintaining a helping relationship are presented to trainees as stimuli. (Author)

  20. 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.

  1. 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…

  2. Application of Particle Simulations to the NRL Laser Experiment.

    DTIC Science & Technology

    1987-12-10

    1987]. The ECDI (and the LHDI to a lesser extent) is suppressed when k1l : 0 [ Lashmore -Davies and Martin, 19731. Simulations with the magnetic field...instability, Phys. Fluids, 15, 662, 1972. Lashmore -Davies, C. N., and T. J. Martin, Electrostatic instabilities driven by an electric current

  3. 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)

  4. 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…

  5. 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.

  6. 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…

  7. Impact of Simulation and Clinical Experience on Self-efficacy in Nursing Students: Intervention Study.

    PubMed

    Kimhi, Einat; Reishtein, Judith L; Cohen, Miri; Friger, Michael; Hurvitz, Nancy; Avraham, Rinat

    2016-01-01

    This study compared the effect of simulation and clinical experience timing on self-confidence/self-efficacy for the nursing process. Using a randomized, double-crossover design, self-efficacy was measured 3 times. Although self-efficacy was significantly higher at time 1 for students who had clinical experience, there was no difference between the groups at the end of the course (time 2). Thus, simulation increased self-confidence/self-efficacy equivalently if placed either before or after clinical experience.

  8. PTSD Symptom Increases in Iraq-Deployed Soldiers: Comparison with NonDeployed Soldiers and Associations with Baseline Symptoms, Deployment Experiences, and Postdeployment Stress

    DTIC Science & Technology

    2010-02-01

    proportion of deployed U.S. forces. Because of the potential fo r greater occupational disruption, less consistent opportunity for combat training...deployment experiences, an occupational context notable for continuity of miliury-rdevanr duties and organizational structure, amI a readily accessible...Tnuma,ic Stres., 21, 290- 300. lOomC)’, R., K"ng, H. K, Kulinsky,j .. Bal<cr. D. G .. V"" .. ling.J. J .. Alpern, R., .t aI. (2007). Men",] healt h of

  9. 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.

  10. Experiments and FEM simulations of fracture behaviors for ADC12 aluminum alloy under impact load

    NASA Astrophysics Data System (ADS)

    Hu, Yumei; Xiao, Yue; Jin, Xiaoqing; Zheng, Haoran; Zhou, Yinge; Shao, Jinhua

    2016-11-01

    Using the combination of experiment and simulation, the fracture behavior of the brittle metal named ADC12 aluminum alloy was studied. Five typical experiments were carried out on this material, with responding data collected on different stress states and dynamic strain rates. Fractographs revealed that the morphologies of fractured specimen under several rates showed different results, indicating that the fracture was predominantly a brittle one in nature. Simulations of the fracture processes of those specimens were conducted by Finite Element Method, whilst consistency was observed between simulations and experiments. In simulation, the Johnson- Cook model was chosen to describe the damage development and to predict the failure using parameters determined from those experimental data. Subsequently, an ADC12 engine mount bracket crashing simulation was conducted and the results indicated good agreement with the experiments. The accordance showed that our research can provide an accurate description for the deforming and fracture processes of the studied alloy.

  11. 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.

  12. 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.

  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. Simulation Experiments: Better Data, Not Just Big Data

    DTIC Science & Technology

    2014-12-01

    attention. Numerous success stories have been promulgated as organizations have sifted through massive volumes of data to find interesting patterns that are...types of insights that can be gained. The simulation world is different. A “data farming ” metaphor captures the notion of purposeful data generation from...done with big data? Most people immediately think of data mining, a term that is ubiquitous in the literature. The concept of data farming is less well

  15. Interaction of light with hematite hierarchical structures: Experiments and simulations

    NASA Astrophysics Data System (ADS)

    Distaso, Monica; Zhuromskyy, Oleksander; Seemann, Benjamin; Pflug, Lukas; Mačković, Mirza; Encina, Ezequiel; Taylor, Robin Klupp; Müller, Rolf; Leugering, Günter; Spiecker, Erdmann; Peschel, Ulf; Peukert, Wolfgang

    2017-03-01

    Mesocrystalline particles have been recognized as a class of multifunctional materials with potential applications in different fields. However, the internal organization of nanocomposite mesocrystals and its influence on the final properties have not yet been investigated. In this paper, a novel strategy based on electrodynamic simulations is developed to shed light on how the internal structure of mesocrystals influences their optical properties. In a first instance, a unified design protocol is reported for the fabrication of hematite/PVP particles with different morphologies such as pseudo-cubes, rods-like and apple-like structures and controlled particle size distributions. The optical properties of hematite/PVP mesocrystals are effectively simulated by taking their aggregate and nanocomposite structure into consideration. The superposition T-Matrix approach accounts for the aggregate nature of mesocrystalline particles and validate the effective medium approximation used in the framework of the Mie theory and electromagnetic simulation such as Finite Element Method. The approach described in our paper provides the framework to understand and predict the optical properties of mesocrystals and more general, of hierarchical nanostructured particles.

  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. Reactive high power impulse magnetron sputtering: combining simulation and experiment

    NASA Astrophysics Data System (ADS)

    Kozak, Tomas; Vlcek, Jaroslav

    2016-09-01

    Reactive high-power impulse magnetron sputtering (HiPIMS) has recently been used for preparation of various oxide films with high application potential, such as TiO2, ZrO2, Ta2O5, HfO2, VO2. Using our patented method of pulsed reactive gas flow control with an optimized reactive gas inlet, we achieved significantly higher deposition rates compared to typical continuous dc magnetron depositions. We have developed a time-dependent model of the reactive HiPIMS. The model includes a depth-resolved description of the sputtered target (featuring sputtering, implantation and knock-on implantation processes) and a parametric description of the discharge plasma (dissociation of reactive gas, ionization and return of sputtered atoms and gas rarefaction). The model uses a combination of experimental and simulation data as input. We have calculated the composition of the target and substrate for several deposition conditions. The simulations predict a reduced compound coverage of the target in HiPIMS compared to the continuous dc sputtering regime which explains the increased deposition rate. The simulations show that an increased dissociation of oxygen in a HiPIMS discharge is beneficial to achieve stoichiometric films on the substrate at high deposition rates.

  18. 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

  19. On the computer simulation of the EPR-Bohm experiment

    SciTech Connect

    McGoveran, D.O.; Noyes, H.P.; Manthey, M.J.

    1988-12-01

    We argue that supraluminal correlation without supraluminal signaling is a necessary consequence of any finite and discrete model for physics. Every day, the commercial and military practice of using encrypted communication based on correlated, pseudo-random signals illustrates this possibility. All that is needed are two levels of computational complexity which preclude using a smaller system to detect departures from ''randomness'' in the larger system. Hence the experimental realizations of the EPR-Bohm experiment leave open the question of whether the world of experience is ''random'' or pseudo-random. The latter possibility could be demonstrated experimentally if a complexity parameter related to the arm length and switching time in an Aspect-type realization of the EPR-Bohm experiment is sufficiently small compared to the number of reliable total counts which can be obtained in practice. 6 refs.

  20. 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.

  1. Structure of colloidosomes with tunable particle density: Simulation versus experiment

    NASA Astrophysics Data System (ADS)

    Fantoni, Riccardo; Salari, Johannes W. O.; Klumperman, Bert

    2012-06-01

    Colloidosomes are created in the laboratory from a Pickering emulsion of water droplets in oil. The colloidosomes have approximately the same diameter and by choosing (hairy) particles of different diameters it is possible to control the particle density on the droplets. The experiment is performed at room temperature. The radial distribution function of the assembly of (primary) particles on the water droplet is measured in the laboratory and in a computer experiment of a fluid model of particles with pairwise interactions on the surface of a sphere.

  2. Comparisons of CTH simulations with measured wave profiles for simple flyer plate experiments

    SciTech Connect

    Thomas, S. A.; Veeser, L. R.; Turley, W. D.; Hixson, R. S.

    2016-06-13

    We conducted detailed 2-dimensional hydrodynamics calculations to assess the quality of simulations commonly used to design and analyze simple shock compression experiments. Such simple shock experiments also contain data where dynamic properties of materials are integrated together. We wished to assess how well the chosen computer hydrodynamic code could do at capturing both the simple parts of the experiments and the integral parts. We began with very simple shock experiments, in which we examined the effects of the equation of state and the compressional and tensile strength models. We increased complexity to include spallation in copper and iron and a solid-solid phase transformation in iron to assess the quality of the damage and phase transformation simulations. For experiments with a window, the response of both the sample and the window are integrated together, providing a good test of the material models. While CTH physics models are not perfect and do not reproduce all experimental details well, we find the models are useful; the simulations are adequate for understanding much of the dynamic process and for planning experiments. However, higher complexity in the simulations, such as adding in spall, led to greater differences between simulation and experiment. Lastly, this comparison of simulation to experiment may help guide future development of hydrodynamics codes so that they better capture the underlying physics.

  3. Comparisons of CTH simulations with measured wave profiles for simple flyer plate experiments

    DOE PAGES

    Thomas, S. A.; Veeser, L. R.; Turley, W. D.; ...

    2016-06-13

    We conducted detailed 2-dimensional hydrodynamics calculations to assess the quality of simulations commonly used to design and analyze simple shock compression experiments. Such simple shock experiments also contain data where dynamic properties of materials are integrated together. We wished to assess how well the chosen computer hydrodynamic code could do at capturing both the simple parts of the experiments and the integral parts. We began with very simple shock experiments, in which we examined the effects of the equation of state and the compressional and tensile strength models. We increased complexity to include spallation in copper and iron and amore » solid-solid phase transformation in iron to assess the quality of the damage and phase transformation simulations. For experiments with a window, the response of both the sample and the window are integrated together, providing a good test of the material models. While CTH physics models are not perfect and do not reproduce all experimental details well, we find the models are useful; the simulations are adequate for understanding much of the dynamic process and for planning experiments. However, higher complexity in the simulations, such as adding in spall, led to greater differences between simulation and experiment. Lastly, this comparison of simulation to experiment may help guide future development of hydrodynamics codes so that they better capture the underlying physics.« less

  4. Simulation and experiment of temperature and cosolvent effects in reversed phase chromatography of peptides.

    PubMed

    Makrodimitris, Kosta; Fernandez, Erik J; Woolf, Thomas B; O'Connell, John P

    2005-01-01

    Experiments and simulations have been carried out for several polar protected peptides in reversed phase chromatography in order to demonstrate how simulation can describe the effects of varying temperature and cosolvent fraction. Comparisons of adsorption chemical potentials from mesoscopic simulations and experimental chromatographic retention data show very good agreement with only one temperature-independent solvent parameter from a single peptide. Such simulations should help guide the design of chromatography experiments with biomolecules and predict retention, including conditions for which empirical correlations such as hydrophobicity scales and molecular descriptors have not been developed.

  5. 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…

  6. 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.

  7. 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

  8. 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.

  9. 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.

  10. Experiments and Numerical Simulation of Mixing under Supercritical Conditions (PREPRINT)

    DTIC Science & Technology

    2011-02-08

    where accurate descriptions of the fluid state are derived from various types of equations [1, 71]. The present simulations rely on the Peng - Robinson equation of... Robinson equation of state cp Constant pressure specific heat cv Constant volume specific heat Cw WALE model constant di Inner jet diameter E Total energy...density ρe Outer jet injection density ρi Inner jet injection density τ Viscous-stress tensor τ t SGS stress tensor a, b, c Coefficients for the Peng

  11. 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.

  12. Membrane surface engineering for protein separations: experiments and simulations.

    PubMed

    Liu, Zizhao; Du, Hongbo; Wickramasinghe, S Ranil; Qian, Xianghong

    2014-09-09

    A bisphosphonate derived ligand was successfully synthesized and grafted from the surface of regenerated cellulose membrane using atom transfer radical polymerization (ATRP) for protein separations. This ligand has a remarkable affinity for arginine (Arg) residues on protein surface. Hydrophilic residues N-(2-hydroxypropyl) methacrylamide (HPMA) was copolymerized to enhance the flexibility of the copolymer ligand and further improve specific protein adsorption. The polymerization of bisphosphonate derivatives was successful for the first time using ATRP. Static and dynamic binding capacities were determined for binding and elution of Arg rich lysozyme. The interaction mechanism between the copolymer ligand and lysozyme was elucidated using classical molecular dynamics (MD) simulations.

  13. 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.

  14. 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.

  15. 2-D Clinostat for Simulated Microgravity Experiments with Arabidopsis Seedlings

    NASA Astrophysics Data System (ADS)

    Wang, Hui; Li, Xugang; Krause, Lars; Görög, Mark; Schüler, Oliver; Hauslage, Jens; Hemmersbach, Ruth; Kircher, Stefan; Lasok, Hanna; Haser, Thomas; Rapp, Katja; Schmidt, Jürgen; Yu, Xin; Pasternak, Taras; Aubry-Hivet, Dorothée; Tietz, Olaf; Dovzhenko, Alexander; Palme, Klaus; Ditengou, Franck Anicet

    2016-04-01

    Ground-based simulators of microgravity such as fast rotating 2-D clinostats are valuable tools to study gravity related processes. We describe here a versatile g-value-adjustable 2-D clinostat that is suitable for plant analysis. To avoid seedling adaptation to 1 g after clinorotation, we designed chambers that allow rapid fixation. A detailed protocol for fixation, RNA isolation and the analysis of selected genes is described. Using this clinostat we show that mRNA levels of LONG HYPOCOTYL 5 (HY5), MIZU-KUSSEI 1 (MIZ1) and microRNA MIR163 are down-regulated in 5-day-old Arabidopsis thaliana roots after 3 min and 6 min of clinorotation using a maximal reduced g-force of 0.02 g, hence demonstrating that this 2-D clinostat enables the characterization of early transcriptomic events during root response to microgravity. We further show that this 2-D clinostat is able to compensate the action of gravitational force as both gravitropic-dependent statolith sedimentation and subsequent auxin redistribution (monitoring D R5 r e v :: G F P reporter) are abolished when plants are clinorotated. Our results demonstrate that 2-D clinostats equipped with interchangeable growth chambers and tunable rotation velocity are suitable for studying how plants perceive and respond to simulated microgravity.

  16. Reactive flow simulations: one-to-one comparison with experiments

    NASA Astrophysics Data System (ADS)

    Vinningland, Jan Ludvig; Neuville, Amelie; Pedersen, Janne; Jettestuen, Espen; Dysthe, Dag Kristian; Hiorth, Aksel

    2014-05-01

    Direct in-situ observations of structural changes in the pore space of porous rocks during reactive flow provide valuable insights into the pore scale mechanisms that govern mineral growth, changes in wetting properties and increased oil recovery. We present simulations of single-phase reactive flow in micrometer sized channels in a calcite (CaCO3) crystal and compare mineralogical and geometrical changes in the numerical results to experimental in-situ observations made with the same flow geometry and reactive fluids. This enables a rigorous test of the numerical model and a method for determining kinetic rate constants that will be used in simulations of reactive flow in chalk geometries. The numerical model is a lattice Boltzmann model (LBM) that moves a set of chemical basis species through the pore space by advection and diffusion. A chemical solver with general kinetic expressions is coupled to the LBM via mass fluxes at the solid-fluid interface. The mineralogy of the solid is described by scalar fields, each representing a mineral phase. The rate of dissolution or precipitation of a mineral depends on the local chemical disequilibrium and on a kinetic rate constant specific to each mineral.

  17. 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.

  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. Receptivity Mechanisms in a Rotating Torus: Experiments and Simulations

    NASA Astrophysics Data System (ADS)

    Clarke, Richard; Calabretto, Sophie; Walbran, Scott; Denier, Jim; Cater, John; Mattner, Trent

    2013-11-01

    We consider the flow within a rotating fluid-filled torus subject to a sudden change in angular velocity. Previous DNS computations showed the occurence of boundary-layer separation (Hewitt et al., JFM 688), which was conjectured to be linked with structures observed in the top-down visualisations of Madden & Mullin (JFM 265). These showed a ``flow front'' in the equatorial plane propagating from the outer wall, the position of which was seen to match well with the separated flow structures seen in the DNS. However, in the experiments a second streak was observed at later times on the opposite wall, not seen in the DNS. To better understand this structure, we present the first measurements of the cross-sectional flow, using PIV on an experiment designed to overcome the optical issues in cross-sectional measurements. These demonstrate both the post-separated flow structures seen in earlier DNS, as well as the appearance of a vortex-pair on the opposite equator. These we believe to be likely candidates for the second fronts noted in the Madden experiments. We hypothesise that this vortex pair is generated by small geometric imperfections, an idea seemingly borne out by striking agreement with new DNS conducted in a modified geometry that better represents experimental reality. This work is funded by the Royal Society of New Zealand Marsden Fund, and the University of Auckland Doctoral Scholarship Programme.

  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. 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.

  2. Mechanical characterisation of Dacron graft: Experiments and numerical simulation.

    PubMed

    Bustos, Claudio A; García-Herrera, Claudio M; Celentano, Diego J

    2016-01-04

    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.

  3. Organic synthesis by quench reactions. [in prebiotic simulation experiment

    NASA Technical Reports Server (NTRS)

    Park, W. K.; Hochstim, A. R.; Ponnamperuma, C.

    1975-01-01

    Study of the effects of chemical quench reactions on the formation of organic compounds at a water surface under simulated primordial earth conditions. A mixture of gaseous methane and ammonia over a water surface was exposed to an arc discharge between an electrode and the water surface, generating reactive species. Various organic molecules were formed by a subsequent quenching of these species generated on the water surface. The effects of these water-surface quench reactions were assessed by comparing the amounts of synthesized molecules to the amounts which formed during the discharge of an arc above the water level. It is concluded that the quench (or wet) discharge led to faster rates of reactions, higher-molecular-weight organic compounds, and one-order-of-magnitude larger yields than the dry discharge.

  4. A study of mesoscale simulations for planar shock experiments on heterogeneous granular materials

    NASA Astrophysics Data System (ADS)

    Schumaker, Merit G.

    There is an interest in producing accurate and reliable computer simulations to predict the dynamic behavior of heterogeneous materials and to use these simulations to gain further insight into experimental results. In so doing, a more complete understanding of the multiple-length scales involved in heterogeneous material compaction can be obtained. Mesoscale computer simulations of dynamically shocked materials have proven to be a beneficial resource in unraveling data not observed in planar shock impact experiments, such as stress and temperature interactions between grains. The modeled mono-dispersed geometry of particles, the densities of each material, equations of state, material properties and many other factors affect the simulated outcomes. By studying and analyzing these variables, many of which highlight the difference between experimental and simulated results, there manifests additional insight into the shock dynamics of the different heterogeneous granular materials. The heterogeneous materials in this study were created both by a "shake and pack" method, where individual grains were randomly seeded into the computational domain and grown until the grains matched the experimental volume fraction and average diameter. Three planar shock experiments were utilized to validate simulation models and parameters: 1. Brake pad powder compaction at Marquette University, 2. Dry sand experiments at Georgia Tech, and 3. Release of dry sand at Cambridge University. Planar shock impact experiments were simulated using two different hydrocode packages: CTH and iSALE. Validated models are then used to setup future dry, water, and possible ice saturated sand release experiments. Particle velocity and stress traces obtained from the computer simulations were compared to VISAR, PDV, and Manganin gage measurements obtained from experiments. The results from simulations are compared to experiments and discussed in this document.

  5. 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

  6. 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.

  7. 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.

  8. Investigation of Low-Pressure Turbine Endwall Flows: Simulations and Experiments (Postprint)

    DTIC Science & Technology

    2015-01-01

    AFRL-RQ-WP-TP-2015-0095 INVESTIGATION OF LOW-PRESSURE TURBINE ENDWALL FLOWS: SIMULATIONS AND EXPERIMENTS (POSTPRINT) R. Sondergaard...Turbomachinery Branch Turbine Engine Division A. Gross New Mexico State University JANUARY 2015 Approved for public release...Conference Proceedings Postprint 01 January 2015 – 01 January 2015 4. TITLE AND SUBTITLE INVESTIGATION OF LOW-PRESSURE TURBINE ENDWALL FLOWS: SIMULATIONS

  9. 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.

  10. Incorporating Real Experience into the Development of a Classroom-Based Simulation

    ERIC Educational Resources Information Center

    Ferry, Brian; Kervin, Lisa; Cambourne, Brian; Turbill, Jan; Hedberg, John; Jonassen, David

    2005-01-01

    This paper reports on the design of an on-line simulation that enhanced preservice teacher practicum experience in the important area of literacy teaching. Research with more than 200 users of the simulation showed that it developed pre-service teacher understanding of complex classroom situations associated with the teaching of literacy by giving…

  11. 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.

  12. Monte Carlo Simulations for Likelihood Analysis of the PEN experiment

    NASA Astrophysics Data System (ADS)

    Glaser, Charles; PEN Collaboration

    2017-01-01

    The PEN collaboration performed a precision measurement of the π+ ->e+νe(γ) branching ratio with the goal of obtaining a relative uncertainty of 5 ×10-4 or better at the Paul Scherrer Institute. A precision measurement of the branching ratio Γ(π -> e ν (γ)) / Γ(π -> μ ν (γ)) can be used to give mass bounds on ``new'', or non V -A, particles and interactions. This ratio also proves to be one of the most sensitive tests for lepton universality. The PEN detector consists of beam counters, an active target, a mini-time projection chamber, multi-wire proportional chamber, a plastic scintillating hodoscope, and a CsI electromagnetic calorimeter. The Geant4 Monte Carlo simulation is used to construct ultra-realistic events by digitizing energies and times, creating synthetic target waveforms, and fully accounting for photo-electron statistics. We focus on the detailed detector response to specific decay and background processes in order to sharpen the discrimination between them in the data analysis. Work supported by NSF grants PHY-0970013, 1307328, and others.

  13. 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.

  14. Simulations of high bootstrap current experiments on Tore Supra

    NASA Astrophysics Data System (ADS)

    Basiuk, V.; Becoulet, A.; Hoang, G. T.; Joffrin, E.; Litaudon, X.; Hutter, T.; Nguyen, F.; Saoutic, B.; Houlberg, W. A.; Kessel, C. E.

    1996-11-01

    The bootstrap current is a good candidate for sustaining a large fraction of the plasma current, f_boot, in the "Advanced Tokamak" regime of a reactor. It is thus important to study the stability of discharges with high f_boot, and to control them. By means of fast wave electron heating (FWEH, up to 9 MW), stationnary high bootstrap discharges (duration ≈ 5 sec. and f_boot ≈ 0.5) are routinely obtained in Tore Supra. The bootstrap profile is computed with the matrix formulation of Houlberg( E. Joffrin et al.), 22nd EPS (1995) 19C, part IV, p 125. and Kessel.( C.E. Kessel, Nuclear Fusion, 34), (1994). The simulation of the loop voltage either with the code CRONOS( F. Kazarian-Vibert et al.), 22nd EPS (1995), 19C, part III, p 373. (1D current diffusion code) using the profile of bootstrap current, or with the knowledge of the resistivity,^1 allows a self consistent determination of the bootstrap current. First results show that the energy enhancement factor H increases linearly with the f_boot. Effects of various plasma parameters on the bootstrap profile, on f_boot, and on the confinement are analysed in a way to implement a current profile control.

  15. 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.

  16. 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.

  17. Hollow Cylinder Simulation Experiments of Galleries in Boom Clay Formation

    NASA Astrophysics Data System (ADS)

    Labiouse, Vincent; Sauthier, Claire; You, Shuang

    2014-01-01

    In the context of nuclear waste disposal in clay formations, laboratory experiments were performed to study at reduced scale the excavation damaged zone (EDZ) induced by the construction of galleries in the Boom clay formation. For this purpose, thick-walled hollow cylindrical samples were subjected (after recovery of in situ stress conditions) to a decrease in the inner confining pressure aiming at mimicking a gallery excavation. X-ray computed tomography (XRCT) scans of the specimens were carried out through the testing cell before and after the mechanical unloading and allowed to quantify the displacements undergone by the clay as a result of the mechanical unloading. The deformation of the hollow cylinders and the inferred extent of the damaged zone around the central hole are found to depend on the orientation of the specimen with respect to the bedding planes and show a great similarity with in situ observations around galleries and boreholes at Mol URL in the Boom clay formation. In the experiments performed on samples cored parallel to the bedding, the damaged zone is not symmetrical with respect to the hole axis and extends more in the direction parallel to the bedding. It is the same for the radial convergence of the hole walls which is larger in the direction parallel to bedding than in the perpendicular one. In contrast, a test on a sample cored perpendicularly to the bedding did not show any ovalisation of the central hole after the mechanical unloading. These observations confirm the significance of the pre-existing planes of weakness (bedding planes) in Boom clay and the need for a correct consideration of the related mechanical anisotropy.

  18. 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.

  19. 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.

  20. Heat flow at solid-liquid interfaces: confrontation between experiment and simulation

    NASA Astrophysics Data System (ADS)

    Cahill, David

    2007-03-01

    Heat transport in nanostructures and nanostructured materials provides a novel paradigm for direct comparisons between the results of experiment and simulation. Time-resolved, pump-probe optical techniques enable measurements of the evolution of temperature on time scales from ps to ns. Our pump-probe experiments take two basic forms: measurements of heat transport across planar interfaces using time-domain thermoreflectance and measurements of heat flow from a metal or semiconductor nanostructure into its surroundings using transient absorption. The systems that we are studying are directly accessible to simulation by classical molecular dynamics on the same time and length scales that are encountered in the experiments. Working with our collaborators, P. Keblinski and his colleagues at RPI, we have made quantitative comparisons between experiment and simulation for heat transport from carbon nanotubes and fullerene molecules into a surrounding fluid; and heat transport across hydrophilic and hydrophobic interfaces with water. Any such comparison must take into account i) non-idealities in the experiments; ii) uncertainties in the potentials and atomic geometries in the computational model; and iii) the fact that classical simulations may include high frequency vibrational modes that are not thermally excited in the experiments. Despite the fact that transport at solid-liquid interfaces is more difficult to measure than more commonly studied solid-solid interfaces, we argue that solid-liquid interfaces provide a more reliable system for quantitative comparisons between experiment and simulation.

  1. 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.

  2. 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.

  3. 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.

  4. Nonlinear polarization of ionic liquids: theory, simulations, experiments

    NASA Astrophysics Data System (ADS)

    Kornyshev, Alexei

    2010-03-01

    Room temperature ionic liquids (RTILs) composed of large, often asymmetric, organic cations and simple or complex inorganic or organic anions do not freeze at ambient temperatures. Their rediscovery some 15 years ago is widely accepted as a ``green revolution'' in chemistry, offering an unlimited number of ``designer'' solvents for chemical and photochemical reactions, homogeneous catalysis, lubrication, and solvent-free electrolytes for energy generation and storage. As electrolytes they are non-volatile, some can sustain without decomposition up to 6 times higher voltages than aqueous electrolytes, and many are environmentally friendly. The studies of RTILs and their applications have reached a critical stage. So many of them can be synthesized - about a thousand are known already - their mixtures can further provide ``unlimited'' number of combinations! Thus, establishing some general laws that could direct the best choice of a RTIL for a given application became crucial; guidance is expected from theory and modelling. But for a physical theory, RTILs comprise a peculiar and complex class of media, the description of which lies at the frontier line of condensed matter theoretical physics: dense room temperature ionic plasmas with ``super-strong'' Coulomb correlations, which behave like glasses at short time-scale, but like viscous liquids at long-time scale. This talk will introduce RTILs to physicists and overview the current understanding of the nonlinear response of RTILs to electric field. It will focus on the theory, simulations, and experimental characterisation of the structure and nonlinear capacitance of the electrical double layer at a charged electrode. It will also discuss pros and contras of supercapacitor applications of RTILs.

  5. 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.

  6. Long-baseline Neutrino Oscillation at DUNE

    NASA Astrophysics Data System (ADS)

    Worcester, Elizabeth; DUNE Collaboration Collaboration

    2017-01-01

    The Deep Underground Neutrino Experiment (DUNE) is a long-baseline neutrino oscillation experiment with primary physics goals of determining the neutrino mass hierarchy and measuring δc P with sufficient sensitivity to discover CP violation in neutrino oscillation. CP violation sensitivity in DUNE requires careful understanding of systematic uncertainty, with contributions expected from uncertainties in the neutrino flux, neutrino interactions, and detector effects. In this presentation, we will describe the expected sensitivity of DUNE to long-baseline neutrino oscillation parameters, how various aspects of the experimental design contribute to that sensitivity, and the planned strategy for constraining systematic uncertainty in these measurements.

  7. 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.

  8. Nanosatellite optical downlink experiment: design, simulation, and prototyping

    NASA Astrophysics Data System (ADS)

    Clements, Emily; Aniceto, Raichelle; Barnes, Derek; Caplan, David; Clark, James; Portillo, Iñigo del; Haughwout, Christian; Khatsenko, Maxim; Kingsbury, Ryan; Lee, Myron; Morgan, Rachel; Twichell, Jonathan; Riesing, Kathleen; Yoon, Hyosang; Ziegler, Caleb; Cahoy, Kerri

    2016-11-01

    The nanosatellite optical downlink experiment (NODE) implements a free-space optical communications (lasercom) capability on a CubeSat platform that can support low earth orbit (LEO) to ground downlink rates>10 Mbps. A primary goal of NODE is to leverage commercially available technologies to provide a scalable and cost-effective alternative to radio-frequency-based communications. The NODE transmitter uses a 200-mW 1550-nm master-oscillator power-amplifier design using power-efficient M-ary pulse position modulation. To facilitate pointing the 0.12-deg downlink beam, NODE augments spacecraft body pointing with a microelectromechanical fast steering mirror (FSM) and uses an 850-nm uplink beacon to an onboard CCD camera. The 30-cm aperture ground telescope uses an infrared camera and FSM for tracking to an avalanche photodiode detector-based receiver. Here, we describe our approach to transition prototype transmitter and receiver designs to a full end-to-end CubeSat-scale system. This includes link budget refinement, drive electronics miniaturization, packaging reduction, improvements to pointing and attitude estimation, implementation of modulation, coding, and interleaving, and ground station receiver design. We capture trades and technology development needs and outline plans for integrated system ground testing.

  9. Simulated Measurements of Cooling in Muon Ionization Cooling Experiment

    SciTech Connect

    Mohayai, Tanaz; Rogers, Chris; Snopok, Pavel

    2016-06-01

    Cooled muon beams set the basis for the exploration of physics of flavour at a Neutrino Factory and for multi-TeV collisions at a Muon Collider. The international Muon Ionization Cooling Experiment (MICE) measures beam emittance before and after an ionization cooling cell and aims to demonstrate emittance reduction in muon beams. In the current MICE Step IV configuration, the MICE muon beam passes through low-Z absorber material for reducing its transverse emittance through ionization energy loss. Two scintillating fiber tracking detectors, housed in spectrometer solenoid modules upstream and downstream of the absorber are used for reconstructing position and momentum of individual muons for calculating transverse emittance reduction. However, due to existence of non-linear effects in beam optics, transverse emittance growth can be observed. Therefore, it is crucial to develop algorithms that are insensitive to this apparent emittance growth. We describe a different figure of merit for measuring muon cooling which is the direct measurement of the phase space density.

  10. Event-by-event simulation of single-neutron experiments to test uncertainty relations

    NASA Astrophysics Data System (ADS)

    De Raedt, H.; Michielsen, K.

    2014-12-01

    Results from a discrete-event simulation of a recent single-neutron experiment that tests Ozawa's generalization of Heisenberg's uncertainty relation are presented. The event-based simulation algorithm reproduces the results of the quantum theoretical description of the experiment but does not require the knowledge of the solution of a wave equation, nor does it rely on detailed concepts of quantum theory. In particular, the data from these non-quantum simulations satisfy uncertainty relations derived in the context of quantum theory. Invited paper presented at QTAP-6.

  11. Study On Numerical Simulation And Experiment Of Fabrication Magnesium Semisolid Slurry By Damper Cooling Tube Method

    NASA Astrophysics Data System (ADS)

    Xie, Shuisheng; Huang, Guojie; Zhang, Xiaoli; Yang, Haoqiang

    2007-05-01

    Damper Cooling Tube (DCT) Method to fabricate the semi-solid metal slurry has been studied in this paper. Firstly, numerical simulation is adopted to investigate the flow process in order to optimize the technical parameters. The temperature effects on the rheological properties of the slurries are also considered. The effects of technical parameters on the slurry properties are studied in detail. Then the experiment was carried out with AZ91 magnesium alloy in order to examine the numerical simulation results. The results of numerical simulation are consistent with the experimental results. According to the numerical and experiment results, the DCT device can fabricate fine semisolid slurry with primary globular phase.

  12. 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

  13. On the nature of the stock market: Simulations and experiments

    NASA Astrophysics Data System (ADS)

    Blok, Hendrik J.

    Over the last few years there has been a surge of activity within the physics community in the emerging field of Econophysics-the study of economic systems from a physicist's perspective. Physicists tend to take a different view than economists and other social scientists, being interested in such topics as phase transitions and fluctuations. In this dissertation two simple models of stock exchange are developed and simulated numerically. The first is characterized by centralized trading with a market maker. Fluctuations are driven by a stochastic component in the agents' forecasts. As the scale of the fluctuations is varied a critical phase transition is discovered. Unfortunately, this model is unable to generate realistic market dynamics. The second model discards the requirement of centralized trading. In this case the stochastic driving force is Gaussian-distributed ``news events'' which are public knowledge. Under variation of the control parameter the model exhibits two phase transitions: both a first- and a second-order (critical). The decentralized model is able to capture many of the interesting properties observed in empirical markets such as fat tails in the distribution of returns, a brief memory in the return series, and long-range correlations in volatility. Significantly, these properties only emerge when the parameters are tuned such that the model spans the critical point. This suggests that real markets may operate at or near a critical point, but is unable to explain why this should be. This remains an interesting open question worth further investigation. One of the main points of the thesis is that these empirical phenomena are not present in the stochastic driving force, but emerge endogenously from interactions between agents. Further, they emerge despite the simplicity of the modeled agents; suggesting complex market dynamics do not arise from the complexity of individual investors but simply from interactions between (even simple) investors

  14. 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…

  15. Transport simulations of ohmic pellet experiments on the TFTR, ASDEX, and ALCATOR-C tokamaks

    SciTech Connect

    Redi, M.H.; Tang, W.M.; Owens, D.K.; Greenwald, M.; Gruber, O.; Kaufmann, M.

    1988-07-01

    Transport simulations of ohmic gas-fuelled and pellet-fuelled experiments have been carried out to test a microinstability-based, profile-consistent model of anomalous transport in tokamaks. Predictions for experiments on the TFTR, ASDEX, and ALCATOR-C tokamaks were found consistent with the observed confinement and temperature measurements. 26 refs., 11 figs., 10 tabs.

  16. 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…

  17. Real Experiments versus Phet Simulations for Better High-School Students' Understanding of Electrostatic Charging

    ERIC Educational Resources Information Center

    Ajredini, Fadil; Izairi, Neset; Zajkov, Oliver

    2014-01-01

    This research investigates the influence of computer simulations (virtual experiments) on one hand and real experiments on the other hand on the conceptual understanding of electrical charging. The investigated sample consists of students in the second year (10th grade) of three gymnasiums in Macedonia. There were two experimental groups and one…

  18. 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.

  19. 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.

  20. 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.

  1. Long Baseline Neutrino Oscillations

    SciTech Connect

    Rebel, Brian; /Fermilab

    2009-10-01

    There is compelling evidence for neutrino flavor change as neutrinos propagate. The evidence for this phenomenon has been provided by several experiments observing neutrinos that traverse distances of several hundred kilometers between production and detection. This review outlines the evidence for neutrino flavor change from such experiments and describes recent results in the field.

  2. 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

  3. Part weight verification between simulation and experiment of plastic part in injection moulding process

    NASA Astrophysics Data System (ADS)

    Amran, M. A. M.; Idayu, N.; Faizal, K. M.; Sanusi, M.; Izamshah, R.; Shahir, M.

    2016-11-01

    In this study, the main objective is to determine the percentage difference of part weight between experimental and simulation work. The effect of process parameters on weight of plastic part is also investigated. The process parameters involved were mould temperature, melt temperature, injection time and cooling time. Autodesk Simulation Moldflow software was used to run the simulation of the plastic part. Taguchi method was selected as Design of Experiment to conduct the experiment. Then, the simulation result was validated with the experimental result. It was found that the minimum and maximum percentage of differential of part weight between simulation and experimental work are 0.35 % and 1.43 % respectively. In addition, the most significant parameter that affected part weight is the mould temperature, followed by melt temperature, injection time and cooling time.

  4. 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.

  5. 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.

  6. 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

  7. Flight Simulator Experiments on Influence of Wideness of Front View for Pilot's Roll Control

    NASA Astrophysics Data System (ADS)

    Kumata, Kazunari; Nishihata, Michiteru; Kobayashi, Osamu

    Fixed based flight simulator experiments were conducted to investigate the influences of wideness of front view for pilot's roll control. In these experiments, the airplane's motion was considered as a single-degree-of-freedom system in roll, and three front views having different view-angle were provided. The results of these experiments showed that the pilot's roll control characteristics, and the pilot's sensing parameter and reaction time for rolling motion were influenced by the differences of wideness of front view in flight simulator.

  8. 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.

  9. 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.

  10. Pore-scale and continuum simulations of solute transport micromodel benchmark experiments

    DOE PAGES

    Oostrom, M.; Mehmani, Y.; Romero-Gomez, P.; ...

    2014-06-18

    Four sets of nonreactive solute transport experiments were conducted with micromodels. Three experiments with one variable, i.e., flow velocity, grain diameter, pore-aspect ratio, and flow-focusing heterogeneity were in each set. The data sets were offered to pore-scale modeling groups to test their numerical simulators. Each set consisted of two learning experiments, for which our results were made available, and one challenge experiment, for which only the experimental description and base input parameters were provided. The experimental results showed a nonlinear dependence of the transverse dispersion coefficient on the Peclet number, a negligible effect of the pore-aspect ratio on transverse mixing,more » and considerably enhanced mixing due to flow focusing. Five pore-scale models and one continuum-scale model were used to simulate the experiments. Of the pore-scale models, two used a pore-network (PN) method, two others are based on a lattice Boltzmann (LB) approach, and one used a computational fluid dynamics (CFD) technique. Furthermore, we used the learning experiments, by the PN models, to modify the standard perfect mixing approach in pore bodies into approaches to simulate the observed incomplete mixing. The LB and CFD models used the learning experiments to appropriately discretize the spatial grid representations. For the continuum modeling, the required dispersivity input values were estimated based on published nonlinear relations between transverse dispersion coefficients and Peclet number. Comparisons between experimental and numerical results for the four challenge experiments show that all pore-scale models were all able to satisfactorily simulate the experiments. The continuum model underestimated the required dispersivity values, resulting in reduced dispersion. The PN models were able to complete the simulations in a few minutes, whereas the direct models, which account for the micromodel geometry and underlying flow and transport physics

  11. Pore-scale and continuum simulations of solute transport micromodel benchmark experiments

    SciTech Connect

    Oostrom, M.; Mehmani, Y.; Romero-Gomez, P.; Tang, Y.; Liu, H.; Yoon, H.; Kang, Q.; Joekar-Niasar, V.; Balhoff, M. T.; Dewers, T.; Tartakovsky, G. D.; Leist, E. A.; Hess, N. J.; Perkins, W. A.; Rakowski, C. L.; Richmond, M. C.; Serkowski, J. A.; Werth, C. J.; Valocchi, A. J.; Wietsma, T. W.; Zhang, C.

    2014-06-18

    Four sets of nonreactive solute transport experiments were conducted with micromodels. Three experiments with one variable, i.e., flow velocity, grain diameter, pore-aspect ratio, and flow-focusing heterogeneity were in each set. The data sets were offered to pore-scale modeling groups to test their numerical simulators. Each set consisted of two learning experiments, for which our results were made available, and one challenge experiment, for which only the experimental description and base input parameters were provided. The experimental results showed a nonlinear dependence of the transverse dispersion coefficient on the Peclet number, a negligible effect of the pore-aspect ratio on transverse mixing, and considerably enhanced mixing due to flow focusing. Five pore-scale models and one continuum-scale model were used to simulate the experiments. Of the pore-scale models, two used a pore-network (PN) method, two others are based on a lattice Boltzmann (LB) approach, and one used a computational fluid dynamics (CFD) technique. Furthermore, we used the learning experiments, by the PN models, to modify the standard perfect mixing approach in pore bodies into approaches to simulate the observed incomplete mixing. The LB and CFD models used the learning experiments to appropriately discretize the spatial grid representations. For the continuum modeling, the required dispersivity input values were estimated based on published nonlinear relations between transverse dispersion coefficients and Peclet number. Comparisons between experimental and numerical results for the four challenge experiments show that all pore-scale models were all able to satisfactorily simulate the experiments. The continuum model underestimated the required dispersivity values, resulting in reduced dispersion. The PN models were able to complete the simulations in a few minutes, whereas the direct models, which account for the micromodel geometry and underlying flow and transport physics, needed

  12. Dynamics of Protonated Peptide Ion Collisions with Organic Surfaces: Consonance of Simulation and Experiment

    SciTech Connect

    Pratihar, Subha; Barnes, George L.; Laskin, Julia; Hase, William L.

    2016-08-18

    In this Perspective mass spectrometry experiments and chemical dynamics simulations are described which have explored the atomistic dynamics of protonated peptide ions, peptide-H+, colliding with organic surfaces. These studies have investigated surface-induced dissociation (SID) for which peptide-H+ fragments upon collision with the surface, peptide-H+ physisorption on the surface, soft landing (SL), and peptide-H+ reaction with the surface, reactive landing (RL). The simulations include QM+MM and QM/MM direct dynamics. For collisions with self-assembled monolayer (SAM) surfaces there is quite good agreement between experiment and simulation in the efficiency of energy transfer to the peptide-H+ ion’s internal degrees of freedom. Both the experiments and simulations show two mechanisms for peptide-H+ fragmentation, i.e. shattering and statistical, RRKM dynamics. Mechanisms for SL are probed in simulations of collisions of protonated dialanine with a perfluorinated SAM surface. RL has been studied experimentally for a number of peptide-H+ + surface systems, and qualitative agreement between simulation and experiment is found for two similar systems.

  13. 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.

  14. Conceptual change in an organic chemistry laboratory: A comparison of computer simulations and traditional laboratory experiments

    NASA Astrophysics Data System (ADS)

    Gaddis, Barbara A.

    2001-12-01

    This quasi-experimental research study examined the effect of computer simulations and hands-on laboratory experiments in enhancing conceptual understanding and alleviating misconceptions of organic chemistry reaction mechanisms. Subjects were sixty-nine sophomore-level organic chemistry students enrolled in four laboratory sections. Laboratory sections were stratified across instructor and randomly assigned to serve as a control or treatment laboratory. Students in the control group performed all hands-on experiments. Students in the treatment group performed hands-on experiments for the first and last part of the semester but performed computer simulations for a five-week period in the middle of the semester. Prior to treatment, groups were equivalent with respect to academic orientation, motivation, formal reasoning ability, and spatial visualization ability. Fifteen common misconceptions held by beginning organic chemistry students were identified from the Covalent Bonding and Structures Test. At the end of the semester, thirteen of these misconceptions persisted. Molecular geometry was the only category of misconceptions that significantly improved as a result of computer simulations, F(1,58) = 6.309, p = .015. No significant differential change was observed in misconceptions about bond polarity, molecular polarity, intermolecular forces, lattice structures, or the octet rule. Computer simulations were found to result in significantly greater conceptual understanding of organic chemistry reactions on two of the experiments, Stereochemistry, F(1,55) = 6.174, p = .016, and Nucleophilic Substitution, F(1,57) = 6.093, p = .017. The other three experiments, Infrared Spectroscopy, Elimination, and Oxymercuration, did not show a significant differential effect between types of laboratory experiences. No significant differences were observed on long-term retention of concepts. Overall conclusions from the study are that neither computer simulations nor hands

  15. Advanced Distributed Simulation Technology II Global Positioning System Interactive Simulation (GPS DIS) Experiment

    DTIC Science & Technology

    2007-11-02

    RWA Manned Simulators 11 3.2.6 Voice Radio Communications: SRE & ASTi 11 3.2.7 ModSAF Operations 11 3.2.8 Data Logger 12 3.2.9 Time Stamper 12...utilized were the Single Channel Ground and Airborne Radio System (SINCGARS) Radio Emulator (SRE), the ASTi Radio, and the Tactical Internet Model (TIM...SGIs at the MWTB and ASTi radios at Ft. Rucker. These two Approved for public release; distribution is unlimited 4 ADST-II-CDRL-GPSDIS-9800018A

  16. Simulator Sickness During Emergency Procedures Training in a Helicopter Simulator: Age, Flight Experience, and Amount Learned

    DTIC Science & Technology

    2007-09-01

    drivers are more susceptible than male drivers" (Hein, p. 610). Age. Walt Disney World’s "Mission: Space" thrill ride left some older riders gulping...since those with more flight hrs naturally tend to fall into older age groups. (McGuinness et al., 1981, p. 25) 3. The SS symptoms reported by the...symptomatology and are useful for determining the pattern of discomfort produced by a given simulator. All scores have as their lowest level a natural zero (no

  17. Pore-scale and Continuum Simulations of Solute Transport Micromodel Benchmark Experiments

    SciTech Connect

    Oostrom, Martinus; Mehmani, Yashar; Romero Gomez, Pedro DJ; Tang, Y.; Liu, H.; Yoon, Hongkyu; Kang, Qinjun; Joekar Niasar, Vahid; Balhoff, Matthew; Dewers, T.; Tartakovsky, Guzel D.; Leist, Emily AE; Hess, Nancy J.; Perkins, William A.; Rakowski, Cynthia L.; Richmond, Marshall C.; Serkowski, John A.; Werth, Charles J.; Valocchi, Albert J.; Wietsma, Thomas W.; Zhang, Changyong

    2016-08-01

    Four sets of micromodel nonreactive solute transport experiments were conducted with flow velocity, grain diameter, pore-aspect ratio, and flow focusing heterogeneity as the variables. The data sets were offered to pore-scale modeling groups to test their simulators. Each set consisted of two learning experiments, for which all results was made available, and a challenge experiment, for which only the experimental description and base input parameters were provided. The experimental results showed a nonlinear dependence of the dispersion coefficient on the Peclet number, a negligible effect of the pore-aspect ratio on transverse mixing, and considerably enhanced mixing due to flow focusing. Five pore-scale models and one continuum-scale model were used to simulate the experiments. Of the pore-scale models, two used a pore-network (PN) method, two others are based on a lattice-Boltzmann (LB) approach, and one employed a computational fluid dynamics (CFD) technique. The learning experiments were used by the PN models to modify the standard perfect mixing approach in pore bodies into approaches to simulate the observed incomplete mixing. The LB and CFD models used these experiments to appropriately discretize the grid representations. The continuum model use published non-linear relations between transverse dispersion coefficients and Peclet numbers to compute the required dispersivity input values. Comparisons between experimental and numerical results for the four challenge experiments show that all pore-scale models were all able to satisfactorily simulate the experiments. The continuum model underestimated the required dispersivity values and, resulting in less dispersion. The PN models were able to complete the simulations in a few minutes, whereas the direct models needed up to several days on supercomputers to resolve the more complex problems.

  18. 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.

  19. Validation of a numerical FSI simulation of an aortic BMHV by in vitro PIV experiments.

    PubMed

    Annerel, S; Claessens, T; Degroote, J; Segers, P; Vierendeels, J

    2014-08-01

    In this paper, a validation of a recently developed fluid-structure interaction (FSI) coupling algorithm to simulate numerically the dynamics of an aortic bileaflet mechanical heart valve (BMHV) is performed. This validation is done by comparing the numerical simulation results with in vitro experiments. For the in vitro experiments, the leaflet kinematics and flow fields are obtained via the particle image velocimetry (PIV) technique. Subsequently, the same case is numerically simulated by the coupling algorithm and the resulting leaflet kinematics and flow fields are obtained. Finally, the results are compared, revealing great similarity in leaflet motion and flow fields between the numerical simulation and the experimental test. Therefore, it is concluded that the developed algorithm is able to capture very accurately all the major leaflet kinematics and dynamics and can be used to study and optimize the design of BMHVs.

  20. 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.

  1. 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.

  2. The THS experiment: Simulating Titan's atmospheric chemistry at low temperature (200 K)

    NASA Astrophysics Data System (ADS)

    Sciamma-O'Brien, Ella; Upton, Kathleen T.; Beauchamp, Jack L.; Salama, Farid

    2016-10-01

    In the Titan Haze Simulation (THS) experiment, Titan's atmospheric chemistry is simulated by plasma discharge in the stream of a supersonic expansion, i.e. at low Titan-like temperature (150 K). Here, we present complementary gas and solid phase analyses of four N2-CH4-based gas mixtures that demonstrate the unique capability of the THS to monitor the chemical growth evolution in order to better understand Titan's chemistry and the origin of aerosol formation.

  3. Toward Technological Application of Non-Newtonian Fluids & Complex Materials/Modeling, Simulation, & Design of Experiments

    DTIC Science & Technology

    2007-11-02

    34Therrmanechanical Equations Governing a Material with Prescribed Temperature-Dependent Density, with Applications to Nonisothernal Plane Poiseuille Flow ", D...1-0431 Materials/Modeling, Simulation , & Design of Experiments 6. AUTHORS M. Gregory Forest & Stephen E. Bechtel 7. PERFORMING ORGANIZATION NAME(S...made significant progress in each of these general areas. We produced high resolution models and codes that simulate molten fiber manufacturing

  4. 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.

  5. 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.

  6. 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

  7. 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.

  8. Simulation Experiment Description Markup Language (SED-ML) Level 1 Version 2.

    PubMed

    Bergmann, Frank T; Cooper, Jonathan; Le Novère, Nicolas; Nickerson, David; Waltemath, Dagmar

    2015-09-04

    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.

  9. 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.

  10. 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.

  11. Protected peptide nanoparticles: experiments and brownian dynamics simulations of the energetics of assembly.

    PubMed

    Chen, Ting; D'Addio, Suzanne M; Kennedy, Michael T; Swietlow, Aleksander; Kevrekidis, Ioannis G; Panagiotopoulos, Athanassios Z; Prud'homme, Robert K

    2009-06-01

    Soluble peptides, susceptible to degradation and clearance in therapeutic applications, have been formulated into protected nanoparticles for the first time through the process of kinetically controlled, block copolymer directed rapid precipitation using Flash NanoPrecipitation. Complementary Brownian dynamics simulations qualitatively model the nanoparticle formation process. The simulations corroborate the hypothesis that the size of nanoparticles decreases with increasing supersaturation. Additionally, the influence of the polymer-peptide interaction energy on the efficiency of nanoparticle protection by polymer surface coverage is elucidated in both experiments and simulations.

  12. Simulations and Experiments of Beam-Beam Effects in e+e- Storage Rings

    SciTech Connect

    Cai, Y.; Seeman, J.; Kozanecki, W.; Ohmi, K.; Tawada, M.; /KEK, Tsukuba

    2005-05-16

    Over the past decade, extensive simulations of beam-beam effects in e{sup +}e{sup -} colliders, based on the particle-in-cell method, were developed to explain many complex experimental observations. Recently, such simulations were used to predict the future luminosity performance of e{sup +}e{sup -} colliders. Some predictions have been proven to be correct in the existing accelerators. In this paper, many effects such as the beam-beam limit, crossing angle, parasitic collisions, betatron spectrum, and the beam-beam lifetime, will be directly compared between simulations and experiments.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. Simulation of ion chamber signals in the n+3 He -> p + t experiment

    NASA Astrophysics Data System (ADS)

    Coppola, Christopher; n3He Collaboration

    2017-01-01

    The parity violating proton directional asymmetry from the capture of polarized neutrons on 3He was measured with a pulsed neutron beam at the Spallation Neutron Source at Oak Ridge National Laboratory. The target is an ion chamber with 3He at 0.476 atmosphere. Signal wires in the chamber have different sensitivities to the physics asymmetry, depdendent on their location and the configuration of the experiment. These geometry factors must be determined by simulation. In addition, simulation estimates the statistical precision of the experiment, optimizes configuration variables, and assists with systematic analysis. To achieve the most accurate simulation of the detector signals, a custom simulation was written in C++ using weighted variables and taking advantage of parallel execution. The phsyics inputs to the simulation came from measurements of the neutron phase space, ENDF cross sections, and PSTAR ionization data. A cell model was applied to combine this physics to produce an accurate simulation of the experimental data. This simulation can be used to calculate accurate and tunable geometry factors, and to produce desired quanities for use in optimization and analysis.

  18. 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.

  19. 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.

  20. [Computer simulation programs as an alternative for classical nerve, muscle and heart experiments using frog tissues].

    PubMed

    Breves, G; Schröder, B

    2000-03-01

    Courses in Physiology include different methodical approaches such as exercises with living animals, experiments using organs or tissues from killed or slaughtered animals, application of diagnostic techniques in humans and theoretical seminars. In addition to these classical approaches computer programs for multimedia simulation of nerve, muscle and heart physiology are now a regular component of courses in Physiology at the School of Veterinary Medicine in Hannover. It is the aim of the present paper to give the first experiences about these new components.

  1. Numerical simulation and interpretation of the European in-pile core debris bed experiment--

    SciTech Connect

    Stubos, A.K.; Buchlin, J.-M. ); Joly, C. )

    1989-01-01

    The first European in-pile experiment is described. The experiment is designed to study, in the frame of the Post Accident Heat Removal program, the long-term coolability of a liquid-saturated core debris bed with internal heat dissipation. A physical model, along with its mathematical formulation and numerical implementation, is developed and used for the simulation and interpretation of the main stages of the experimental procedure.

  2. Measuring the Detection Efficiency of the Kepler Pipeline: The First Results from a Simulated Transit Experiment Spanning the Full Observation Baseline

    NASA Astrophysics Data System (ADS)

    Christiansen, Jessie Leigh; Clarke, Bruce; Burke, Christopher; Seader, Shawn; Jenkins, Jon Michael; Twicken, Joseph; smith, jeffrey; Batalha, Natalie; haas, michael; thompson, susan

    2015-08-01

    As the full Kepler dataset is analysed and made available, the Kepler project has published a series of planet candidate lists. In order for both the project and the community to determine the true planet occurrence rates from these candidate lists, we need to measure the detection efficiency of the Kepler pipeline from which the candidates are produced, that is, the rate at which planets are missed in the analysis. We present here the preliminary results from the first empirical measurement of the detection efficiency of the pipeline on the full seventeen quarters of data, extending our previous measurements using one and four quarters of data. For the first time, we are also able to use the identical data products and pipeline versions as those used to generate the Q1-Q17 planet candidate catalogue, and as a consequence, the measured detection efficiency can be used directly in the inference of the planet occurrence rates. In particular, we examine the impact of the large rate of false positives in the Kepler planet candidate lists at periods of 200-400 days, due to temperature-dependent electronic artifacts in the Kepler CCDs, on the detection of real planets at those periods, which are critical to habitable zone occurrence rate calculations.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. Comparison of hydrodynamic simulations with two-shockwave drive target experiments

    NASA Astrophysics Data System (ADS)

    Karkhanis, Varad; Ramaprabhu, Praveen; Buttler, William

    2015-11-01

    We consider hydrodynamic continuum simulations to mimic ejecta generation in two-shockwave target experiments, where metallic surface is loaded by two successive shock waves. Time of second shock in simulations is determined to match experimental amplitudes at the arrival of the second shock. The negative Atwood number A --> - 1 of ejecta simulations leads to two successive phase inversions of the interface corresponding to the passage of the shocks from heavy to light media in each instance. Metallic phase of ejecta (solid/liquid) depends on shock loading pressure in the experiment, and we find that hydrodynamic simulations quantify the liquid phase ejecta physics with a fair degree of accuracy, where RM instability is not suppressed by the strength effect. In particular, we find that our results of free surface velocity, maximum ejecta velocity, and maximum ejecta areal density are in excellent agreement with their experimental counterparts, as well as ejecta models. We also comment on the parametric space for hydrodynamic simulations in which they can be used to compare with the target experiments. This work was supported in part by the (U.S.) Department of Energy (DOE) under Contract No. DE-AC52-06NA2-5396.

  8. Comparison of hydrodynamic simulations with two-shockwave drive target experiments

    NASA Astrophysics Data System (ADS)

    Karkhanis, Varad; Ramaprabhu, Praveen; Buttler, William

    2015-11-01

    We consider hydrodynamic continuum simulations to mimic ejecta generation in two-shockwave target experiments, where metallic surface is loaded by two successive shock waves. Time of second shock in simulations is determined to match experimental amplitudes at the arrival of the second shock. The negative Atwood number (A --> - 1) of ejecta simulations leads to two successive phase inversions of the interface corresponding to the passage of the shocks from heavy to light media in each instance. Metallic phase of ejecta (solid/liquid) depends on shock loading pressure in the experiment, and we find that hydrodynamic simulations quantify the liquid phase ejecta physics with a fair degree of accuracy, where RM instability is not suppressed by the strength effect. In particular, we find that our results of free surface velocity, maximum ejecta velocity, and maximum ejecta areal density are in excellent agreement with their experimental counterparts, as well as ejecta models. We also comment on the parametric space for hydrodynamic simulations in which they can be used to compare with the target experiments.

  9. Developing high energy, stable laser wakefield accelerators: particle simulations and experiments

    NASA Astrophysics Data System (ADS)

    Geddes, Cameron

    2006-10-01

    Laser driven wakefield accelerators produce accelerating fields thousands of times those achievable in conventional radiofrequency accelerators, and recent experiments have produced high energy electron bunches with low emittance and energy spread. Challenges now include control and reproducibility of the electron beam, further improvements in energy spread, and scaling to higher energies. We present large-scale particle in cell simulations together with recent experiments towards these goals. In LBNL experiments the relativistically intense drive pulse was guided over more than 10 diffraction ranges by plasma channels. Guiding beyond the diffraction range improved efficiency by allowing use of a smaller laser spot size (and hence higher intensities) over long propagation distances. At a drive pulse power of 9 TW, electrons were trapped from the plasma and beams of percent energy spread containing > 200pC charge above 80 MeV with normalized emittance estimated at < 2 π-mm-mrad were produced. Energies have now been scaled to 1 GeV using 40 TW of laser power. Particle simulations and data showed that the high quality bunch in recent experiments was formed when beam loading turned off injection after initial self trapping, creating a bunch of electrons isolated in phase space. A narrow energy spread beam was then obtained by extracting the bunch as it outran the accelerating phase of the wake. Large scale simulations coupled with experiments are now under way to better understand the optimization of such accelerators including production of reproducible electron beams and scaling to energies beyond a GeV. Numerical resolution and two and three dimensional effects are discussed as well as diagnostics for application of the simulations to experiments. Effects including injection and beam dynamics as well as pump laser depletion and reshaping will be described, with application to design of future experiments. Supported by DOE grant DE-AC02-05CH11231 and by an INCITE

  10. Cyclic Voltammetry Simulations with DigiSim Software: An Upper-Level Undergraduate Experiment

    ERIC Educational Resources Information Center

    Messersmith, Stephania J.

    2014-01-01

    An upper-division undergraduate chemistry experiment is described which utilizes DigiSim software to simulate cyclic voltammetry (CV). Four mechanisms were studied: a reversible electron transfer with no subsequent or proceeding chemical reactions, a reversible electron transfer followed by a reversible chemical reaction, a reversible chemical…

  11. Statistical comparison between experiments and numerical simulations of shock-accelerated gas cylinders

    SciTech Connect

    Rider, William; Kamm, J. R.; Zoldi, C. A.; Tomkins, C. D.

    2002-01-01

    We present detailed spatial analysis comparing experimental data and numerical simulation results for Richtmyer-Meshkov instability experiments of Prestridge et al. and Tomkins et al. These experiments consist, respectively, of one and two diffuse cylinders of sulphur hexafluoride (SF{sub 6}) impulsively accelerated by a Mach 1.2 shockwave in air. The subsequent fluid evolution and mixing is driven by the deposition of baroclinic vorticity at the interface between the two fluids. Numerical simulations of these experiments are performed with three different versions of high resolution finite volume Godunov methods, including a new weighted adaptive Runge-Kutta (WARK) scheme. We quantify the nature of the mixing using using integral measures as well as fractal analysis and continuous wavelet transforms. Our investigation of the gas cylinder configurations follows the path of our earlier studies of the geometrically and dynamically more complex gas 'curtain' experiment. In those studies, we found significant discrepancies in the details of the experimentally measured mixing and the details of the numerical simulations. Here we evaluate the effects of these hydrodynamic integration techniques on the diffuse gas cylinder simulations, which we quantitatively compare with experimental data.

  12. 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)

  13. Using Laboratory Experiments and Circuit Simulation IT Tools in an Undergraduate Course in Analog Electronics

    ERIC Educational Resources Information Center

    Baltzis, Konstantinos B.; Koukias, Konstantinos D.

    2009-01-01

    Laboratory-based courses play a significant role in engineering education. Given the role of electronics in engineering and technology, laboratory experiments and circuit simulation IT tools are used in their teaching in several academic institutions. This paper discusses the characteristics and benefits of both methods. The content and structure…

  14. 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.

  15. 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

  16. 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…

  17. 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…

  18. A Simulation Experience to Sensitize Persons to the Sensory Losses of the Elderly.

    ERIC Educational Resources Information Center

    Robichaud, M. Phyllis; Brown, Miner L.

    This paper describes a simulation experience to help people understand the feelings of the elderly through a program conducted by the Jewish Center for Aged in Chesterfield, MO. The four-hour program is divided into four sections: (1) a true-false test is given to assess participants' concepts of the aged; (2) inhibitors are applied to limit…

  19. Computer-intensive simulation of solid-state NMR experiments using SIMPSON

    NASA Astrophysics Data System (ADS)

    Tošner, Zdeněk; Andersen, Rasmus; Stevensson, Baltzar; Edén, Mattias; Nielsen, Niels Chr.; Vosegaard, Thomas

    2014-09-01

    Conducting large-scale solid-state NMR simulations requires fast computer software potentially in combination with efficient computational resources to complete within a reasonable time frame. Such simulations may involve large spin systems, multiple-parameter fitting of experimental spectra, or multiple-pulse experiment design using parameter scan, non-linear optimization, or optimal control procedures. To efficiently accommodate such simulations, we here present an improved version of the widely distributed open-source SIMPSON NMR simulation software package adapted to contemporary high performance hardware setups. The software is optimized for fast performance on standard stand-alone computers, multi-core processors, and large clusters of identical nodes. We describe the novel features for fast computation including internal matrix manipulations, propagator setups and acquisition strategies. For efficient calculation of powder averages, we implemented interpolation method of Alderman, Solum, and Grant, as well as recently introduced fast Wigner transform interpolation technique. The potential of the optimal control toolbox is greatly enhanced by higher precision gradients in combination with the efficient optimization algorithm known as limited memory Broyden-Fletcher-Goldfarb-Shanno. In addition, advanced parallelization can be used in all types of calculations, providing significant time reductions. SIMPSON is thus reflecting current knowledge in the field of numerical simulations of solid-state NMR experiments. The efficiency and novel features are demonstrated on the representative simulations.

  20. Computer-intensive simulation of solid-state NMR experiments using SIMPSON.

    PubMed

    Tošner, Zdeněk; Andersen, Rasmus; Stevensson, Baltzar; Edén, Mattias; Nielsen, Niels Chr; Vosegaard, Thomas

    2014-09-01

    Conducting large-scale solid-state NMR simulations requires fast computer software potentially in combination with efficient computational resources to complete within a reasonable time frame. Such simulations may involve large spin systems, multiple-parameter fitting of experimental spectra, or multiple-pulse experiment design using parameter scan, non-linear optimization, or optimal control procedures. To efficiently accommodate such simulations, we here present an improved version of the widely distributed open-source SIMPSON NMR simulation software package adapted to contemporary high performance hardware setups. The software is optimized for fast performance on standard stand-alone computers, multi-core processors, and large clusters of identical nodes. We describe the novel features for fast computation including internal matrix manipulations, propagator setups and acquisition strategies. For efficient calculation of powder averages, we implemented interpolation method of Alderman, Solum, and Grant, as well as recently introduced fast Wigner transform interpolation technique. The potential of the optimal control toolbox is greatly enhanced by higher precision gradients in combination with the efficient optimization algorithm known as limited memory Broyden-Fletcher-Goldfarb-Shanno. In addition, advanced parallelization can be used in all types of calculations, providing significant time reductions. SIMPSON is thus reflecting current knowledge in the field of numerical simulations of solid-state NMR experiments. The efficiency and novel features are demonstrated on the representative simulations.

  1. Freezing of mixtures confined in silica nanopores: experiment and molecular simulation.

    PubMed

    Coasne, Benoit; Czwartos, Joanna; Sliwinska-Bartkowiak, Malgorzata; Gubbins, Keith E

    2010-08-28

    Freezing of mixtures confined in silica nanopores is investigated by means of experiment and molecular simulation. The experiments consist of differential scanning calorimetry and dielectric relaxation spectroscopy measurements for CCl(4)/C(6)H(5)Br mixtures confined in Vycor having pores with a mean diameter of about D=4.2 nm. Molecular simulations consist of grand canonical Monte Carlo simulations combined with the parallel tempering technique for Lennard-Jones Ar/Kr mixtures confined in a silica cylindrical nanopore with a diameter of D=3.2 nm. The experimental and molecular simulation data provide a consistent picture of freezing of mixtures in cylindrical silica nanopores having a size smaller than ten times the size of the confined molecules. No sharp change in the properties of the confined mixture occurs upon melting, which suggests that the confined system does not crystallize. In the case of the molecular simulations, this result is confirmed by the fact that except for the contact layer, the percentage of crystal-like atoms is less than 6% (whatever the temperature). The molecular simulations also show that the composition of the mixture is shifted, upon confinement, toward the component having the strongest wall/fluid attraction.

  2. SBS in Long-Scale-Length Plasmas for Direct-Drive ICF: Comparing Experiments with Simulations

    NASA Astrophysics Data System (ADS)

    Seka, W.; Myatt, J.; Maximov, A. V.; Short, R. W.; Craxton, R. S.; Regan, S. P.; Meyerhofer, D. D.; Stoeckl, C.; Yaakobi, B.

    2002-11-01

    Single- and multiple-beam SBS experiments will be compared to detailed simulations for plasmas representing direct-drive NIF conditions. The SBS spectra exhibit red- and blue-shifted features. The blue-shifted component is clearly identified with SBS in a flat velocity gradient that rapidly moves to higher expansion velocities. This feature can be reduced or suppressed by beam-smoothing techniques in both the experiments and simulations. The red-shifted spectrum originates near the critical density; it arises from EM seeding and is not reduced by beam smoothing. The agreement between experimental data and simulations now allows for more-confident extrapolation to other plasma conditions. This work was supported by the U.S. Department of Energy Office of Inertial Confinement Fusion under Cooperative Agreement No. DE-FC03-92SF19460.

  3. Experiment and molecular dynamics simulation of nanoindentation of body centered cubic iron.

    PubMed

    Lu, Cheng; Gao, Yuan; Michal, Guillaume; Deng, Guanyu; Huynh, Nam N; Zhu, Hongtao; Liu, Xianghua; Tieu, Anh Kiet

    2009-12-01

    Experiments and molecular dynamics (MD) simulations have been conducted to investigate the nanoindentation behaviours of iron with body centered cubic (BCC) structure. The experiments show that the indentation hardness decreases with the indentation depth and it changes sharply for a small depth. Two cases with different crystallographic orientations have been simulated. The indentation plane is (010) for Case I and (111) for Case II, respectively. The calculated harness (17.4 GPa for Case I and 22.6 GPa for Case II) are in reasonable agreement with the experimental value (24.2 GPa). The simulation results show that the crystallographic orientation significantly influences the indentation deformation. Case I and Case II exhibit different deformation patterns. The indentation force and the hardness in Case I are smaller than Case II. It is also found that the pileup around the indenter is mainly formed along [110] direction for both cases.

  4. Simulation and Experiment on Direct Continuous Casting Process of Lead Frame Copper Alloy

    NASA Astrophysics Data System (ADS)

    Guojie, Huang; Shuisheng, Xie; Lei, Cheng

    2010-06-01

    Direct Continuous Casting (D.C.C) is an important method in casting lead frame copper alloy. In this paper, numerical simulation is adopted to investigate the casting process in order to optimize the D.C.C technical parameters, such as the casting temperature, casting speed and cooling intensity. According to the numerical results, the reasonable parameters are that the casting temperature is between 1413 K˜1413 K, the casting speed is between 8 m/h˜10 m/h and the speed of cooling water is between 4.2 m/s˜4.6 m/s. And the depth of liquid-solid boundary is measured in different casting temperature and casting speed by experiments. The results show the actual measurements have a little deviation with the numerical simulation. The results of numerical simulation provide the significant reference to the actual experiments.

  5. Simulation Studies of Backgrounds for the Fermilab SeaQuest Experiment (E906)

    NASA Astrophysics Data System (ADS)

    Ma, Puyang; Aidala, Christine; E906/SeaQuest Collaboration

    2016-09-01

    The Fermilab SeaQuest experiment uses a 120 GeV proton beam on targets of liquid hydrogen, liquid deuterium, and solid nuclear targets of carbon, iron, and tungsten. The experiment measures the Drell-Yan process of quark-antiquark annihilation to produce muon pairs, with the main physics goal of studying the sea quark distributions in the nucleon and nuclei. Since quark and antiquark annihilation to dimuons is a rare process, there are significant backgrounds due to muons from the decay of pions produced in the target and beam dump. These backgrounds are being studied via simulated proton interactions in a GEANT implementation of the experimental setup. Full simulation of these backgrounds has proved to be difficult because of the extensive computer time needed. Studies to speed up the simulation process will be presented. NSF.

  6. Comparison of Monte Carlo simulations of cytochrome b6f with experiment using Latin hypercube sampling.

    PubMed

    Schumaker, Mark F; Kramer, David M

    2011-09-01

    We have programmed a Monte Carlo simulation of the Q-cycle model of electron transport in cytochrome b(6)f complex, an enzyme in the photosynthetic pathway that converts sunlight into biologically useful forms of chemical energy. Results were compared with published experiments of Kramer and Crofts (Biochim. Biophys. Acta 1183:72-84, 1993). Rates for the simulation were optimized by constructing large numbers of parameter sets using Latin hypercube sampling and selecting those that gave the minimum mean square deviation from experiment. Multiple copies of the simulation program were run in parallel on a Beowulf cluster. We found that Latin hypercube sampling works well as a method for approximately optimizing very noisy objective functions of 15 or 22 variables. Further, the simplified Q-cycle model can reproduce experimental results in the presence or absence of a quinone reductase (Q(i)) site inhibitor without invoking ad hoc side-reactions.

  7. Development of microwave interferometer system for divertor simulation experiments in GAMMA 10/PDX

    NASA Astrophysics Data System (ADS)

    Kohagura, J.; Wang, X.; Kanno, S.; Yoshikawa, M.; Kuwahara, D.; Nagayama, Y.; Shima, Y.; Chikatsu, M.; Nojiri, K.; Sakamoto, M.; Imai, T.; Nakashima, Y.; Mase, A.

    2015-12-01

    Microwave interferometer has newly been installed on GAMMA 10/PDX for divertor simulation study. A divertor simulation experimental module (D-module) is used to investigate the physics of divertor in the end-cell of GAMMA 10/PDX where an open magnetic field configuration is formed. D-module has a rectangular chamber with an inlet aperture. Two tungsten target plates are mounted in V-shape inside the chamber. In order to develop understandings of divertor simulation experiments the microwave interferometer using heterodyne scheme and a 1D horn-antenna mixer array (HMA) is applied to obtain electron density and density distribution inside the V-shaped target plates. Line-averaged electron density distributions inside D-module are first observed in H2 gas injection experiments.

  8. Hanford Site technical baseline database

    SciTech Connect

    Porter, P.E., Westinghouse Hanford

    1996-05-10

    This document includes a cassette tape that contains the Hanford specific files that make up the Hanford Site Technical Baseline Database as of May 10, 1996. The cassette tape also includes the delta files that delineate the differences between this revision and revision 3 (April 10, 1996) of the Hanford Site Technical Baseline Database.

  9. 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)

  10. Large short-baseline ν¯μ disappearance

    NASA Astrophysics Data System (ADS)

    Giunti, Carlo; Laveder, Marco

    2011-03-01

    We analyze the LSND, KARMEN, and MiniBooNE data on short-baseline ν¯μ→ν¯e oscillations and the data on short-baseline ν¯e disappearance obtained in the Bugey-3 and CHOOZ reactor experiments in the framework of 3+1 antineutrino mixing, taking into account the MINOS observation of long-baseline ν¯μ disappearance and the KamLAND observation of very-long-baseline ν¯e disappearance. We show that the fit of the data implies that the short-baseline disappearance of ν¯μ is relatively large. We obtain a prediction of an effective amplitude sin⁡22ϑμμ≳0.1 for short-baseline ν¯μ disappearance generated by 0.2≲Δm2≲1eV2, which could be measured in future experiments.

  11. SUGV baseline autonomy using ROS

    NASA Astrophysics Data System (ADS)

    Stump, Ethan; Sadler, Laurel; Baran, David

    2011-05-01

    Currently, the 3000+ robotic systems fielded in theater are entirely teleoperated. This constant dependence on operator control introduces several problems, including a large cognitive load on the operator and a limited ability for the operator to maintain an appropriate level of situational awareness of his surroundings. One solution to reduce the dependence on teleoperation is to develop autonomous behaviors for the robot to reduce the strain on the operator. We consider mapping and navigation to be fundamental to the development of useful field autonomy for small unmanned ground vehicles (SUGVs). To this end, we have developed baseline autonomous capabilities for our SUGV platforms, making use of the open-source Robot Operating System (ROS) software from Willow Garage, Inc. Their implementations of mapping and navigation are drawn from the most successful published academic algorithms in robotics. In this paper, we describe how we bridged our previous work with the Packbot Explorer to incorporate a new processing payload, new sensors, and the ROS system configured to perform the high-level autonomy tasks of mapping and waypoint navigation. We document our most successful parameter selection for the ROS navigation software in an indoor environment and present results of a mapping experiment.

  12. Comparison between summing-up algorithms to determine areas of small peaks on high baselines

    NASA Astrophysics Data System (ADS)

    Shi, Quanlin; Zhang, Jiamei; Chang, Yongfu; Qian, Shaojun

    2005-12-01

    It is found that the minimum detectable activity (MDA) has a same tendency as the relative standard deviation (RSD) and a particular application is characteristic of the ratio of the peak area to the baseline height. Different applications need different algorithms to reduce the RSD of peak areas or the MDA of potential peaks. A model of Gaussian peaks superposed on linear baselines is established to simulate the multichannel spectrum and summing-up algorithms such as total peak area (TPA), and Covell and Sterlinski are compared to find the most appropriate algorithm for different applications. The results show that optimal Covell and Sterlinski algorithms will yield MDA or RSD half lower than TPA when the areas of small peaks on high baselines are to be determined. The conclusion is proved by experiment.

  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. Simulated Order Verification and Medication Reconciliation during an Introductory Pharmacy Practice Experience

    PubMed Central

    Chesson, Melissa M.; Momary, Kathryn M.

    2015-01-01

    Objective. To create, implement, and assess a simulated medication reconciliation and an order verification activity using hospital training software. Design. A simulated patient with medication orders and home medications was built into existing hospital training software. Students in an institutional introductory pharmacy practice experience (IPPE) reconciled the patient’s medications and determined whether or not to verify the inpatient orders based on his medical history and laboratory data. After reconciliation, students identified medication discrepancies and documented their rationale for rejecting inpatient orders. Assessment. For a 3-year period, the majority of students agreed the simulation enhanced their learning, taught valuable clinical decision-making skills, integrated material from previous courses, and stimulated their interest in institutional pharmacy. Overall feedback from student evaluations about the IPPE also was favorable. Conclusion. Use of existing hospital training software can affordably simulate the pharmacist’s role in order verification and medication reconciliation, as well as improve clinical decision-making. PMID:27168609

  15. The simulation and experiment research of harmonic signals based on wavelength modulation spectroscopy

    NASA Astrophysics Data System (ADS)

    Qu, Dong-sheng; Hong, Yan-ji; Wang, Guang-yu; Wang, Ming-dong

    2016-10-01

    In order to improve the measurement based on the wavelength modulation spectroscopy technology, a new simulation method of harmonic signals is analyzed and studied. After choosing one H2O absorption line (7185.60cm-1), the transmitted laser signals can be simulated using the measured incident laser signals and fitted laser frequency signals. The simulation of harmonic signals can be realized after creating the lock-in amplifier and calibrated using measured second-harmonic signal. The reliability of this method can be verified according to compare the simulation results with experiment results. At last, the application of this method in the flow field diagnosis is analyzed. It can lay the foundation of engineering application based on wavelength modulation spectroscopy.

  16. Interim Service ISDN Satellite (ISIS) simulator development for advanced satellite designs and experiments

    NASA Technical Reports Server (NTRS)

    Pepin, Gerard R.

    1992-01-01

    The simulation development associated with the network models of both the Interim Service Integrated Services Digital Network (ISDN) Satellite (ISIS) and the Full Service ISDN Satellite (FSIS) architectures is documented. The ISIS Network Model design represents satellite systems like the Advanced Communications 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 communications 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 event 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.

  17. Simulations of laser propagation and ionization in l'OASIS experiments

    SciTech Connect

    Dimitrov, D.A.; Bruhwiler, D.L.; Leemans, W.; Esarey, E.; Catravas, P.; Toth, C.; Shadwick, B.; Cary, J.R.; Giacone, R.

    2002-06-30

    We have conducted particle-in-cell simulations of laser pulse propagation through neutral He, including the effects of tunneling ionization, within the parameter regime of the l'OASIS experiments [1,2] at the Lawrence Berkeley National Laboratory (LBNL). The simulations show the theoretically predicted [3] blue shifting of the laser frequency at the leading edge of the pulse. The observed blue shifting is in good agreement with the experimental data. These results indicate that such computations can be used to accurately simulate a number of important effects related to tunneling ionization for laser-plasma accelerator concepts, such as steepening due to ionization-induced pump depletion, which can seed and enhance instabilities. Our simulations show self-modulation occurring earlier when tunneling ionization is included then for a pre-ionized plasma.

  18. End-to-End Beam Simulations for the New Muon G-2 Experiment at Fermilab

    SciTech Connect

    Korostelev, Maxim; Bailey, Ian; Herrod, Alexander; Morgan, James; Morse, William; Stratakis, Diktys; Tishchenko, Vladimir; Wolski, Andrzej

    2016-06-01

    The aim of the new muon g-2 experiment at Fermilab is to measure the anomalous magnetic moment of the muon with an unprecedented uncertainty of 140 ppb. A beam of positive muons required for the experiment is created by pion decay. Detailed studies of the beam dynamics and spin polarization of the muons are important to predict systematic uncertainties in the experiment. In this paper, we present the results of beam simulations and spin tracking from the pion production target to the muon storage ring. The end-to-end beam simulations are developed in Bmad and include the processes of particle decay, collimation (with accurate representation of all apertures) and spin tracking.

  19. LABORATORY EXPERIMENTS, NUMERICAL SIMULATIONS, AND ASTRONOMICAL OBSERVATIONS OF DEFLECTED SUPERSONIC JETS: APPLICATION TO HH 110

    SciTech Connect

    Hartigan, P.; Carver, R.; Foster, J. M.; Rosen, P. A.; Williams, R. J. R.; Wilde, B. H.; Coker, R. F.; Hansen, J. F.; Blue, B. E.; Frank, A.

    2009-11-01

    Collimated supersonic flows in laboratory experiments behave in a similar manner to astrophysical jets provided that radiation, viscosity, and thermal conductivity are unimportant in the laboratory jets and that the experimental and astrophysical jets share similar dimensionless parameters such as the Mach number and the ratio of the density between the jet and the ambient medium. When these conditions apply, laboratory jets provide a means to study their astrophysical counterparts for a variety of initial conditions, arbitrary viewing angles, and different times, attributes especially helpful for interpreting astronomical images where the viewing angle and initial conditions are fixed and the time domain is limited. Experiments are also a powerful way to test numerical fluid codes in a parameter range in which the codes must perform well. In this paper, we combine images from a series of laboratory experiments of deflected supersonic jets with numerical simulations and new spectral observations of an astrophysical example, the young stellar jet HH 110. The experiments provide key insights into how deflected jets evolve in three dimensions, particularly within working surfaces where multiple subsonic shells and filaments form, and along the interface where shocked jet material penetrates into and destroys the obstacle along its path. The experiments also underscore the importance of the viewing angle in determining what an observer will see. The simulations match the experiments so well that we can use the simulated velocity maps to compare the dynamics in the experiment with those implied by the astronomical spectra. The experiments support a model where the observed shock structures in HH 110 form as a result of a pulsed driving source rather than from weak shocks that may arise in the supersonic shear layer between the Mach disk and bow shock of the jet's working surface.

  20. Predoctoral Dental Students' Perceptions of Dental Implant Training: Effect of Preclinical Simulation and Clinical Experience.

    PubMed

    Prasad, Soni; Bansal, Naveen

    2017-04-01

    The aims of this study were to assess 1) differences in perceptions of dental implant training between dental students who received didactic training alone (control group) and those who received didactic plus simulation training (test group); 2) differences in response between students with and without clinical experience in implant dentistry; and 3) the interaction effect of simulation training and clinical experience on students' satisfaction. A survey was distributed to the control group in 2014 and to the test group in 2015; both groups were at the same U.S. dental school. Data were collected on confidence levels with various implant restorative procedures along with overall satisfaction and number of implant restorations performed by each student. The response rate was 78.7% in the control group and 81.3% in the test group. In the control group, 85.7% of students reported being satisfied with implant training compared to 90.8% of students in the test group. The interaction effect of simulation training and clinical experience on overall student satisfaction was OR=1.5 at 95% CI: 0.8, 3.0. The students who had clinical experience with implant restorative procedures had significantly greater satisfaction than those who did not (OR=4.8, 95% CI: 2.1, 11.1, p<0.01). This study found that both the simulation and clinical experience affected these students' confidence and satisfaction levels with implant education: they were almost five times more satisfied with implant training when clinical experience in implant restorative procedures was a part of their implant education.

  1. Baseline Graphite Characterization: First Billet

    SciTech Connect

    Mark C. Carroll; Joe Lords; David Rohrbaugh

    2010-09-01

    The Next Generation Nuclear Plant Project Graphite Research and Development program is currently establishing the safe operating envelope of graphite core components for a very high temperature reactor design. To meet this goal, the program is generating the extensive amount of quantitative data necessary for predicting the behavior and operating performance of the available nuclear graphite grades. In order determine the in-service behavior of the graphite for the latest proposed designs, two main programs are underway. The first, the Advanced Graphite Creep (AGC) program, is a set of experiments that are designed to evaluate the irradiated properties and behavior of nuclear grade graphite over a large spectrum of temperatures, neutron fluences, and compressive loads. Despite the aggressive experimental matrix that comprises the set of AGC test runs, a limited amount of data can be generated based upon the availability of space within the Advanced Test Reactor and the geometric constraints placed on the AGC specimens that will be inserted. In order to supplement the AGC data set, the Baseline Graphite Characterization program will endeavor to provide supplemental data that will characterize the inherent property variability in nuclear-grade graphite without the testing constraints of the AGC program. This variability in properties is a natural artifact of graphite due to the geologic raw materials that are utilized in its production. This variability will be quantified not only within a single billet of as-produced graphite, but also from billets within a single lot, billets from different lots of the same grade, and across different billets of the numerous grades of nuclear graphite that are presently available. The thorough understanding of this variability will provide added detail to the irradiated property data, and provide a more thorough understanding of the behavior of graphite that will be used in reactor design and licensing. This report covers the

  2. Analysis of cavity pressure and warpage of polyoxymethylene thin walled injection molded parts: Experiments and simulations

    NASA Astrophysics Data System (ADS)

    Guerrier, P.; Tosello, G.; Hattel, J. H.

    2015-05-01

    Process analysis and simulations on molding experiments of 3D thin shell parts have been conducted. Moldings were carried out with polyoxymethylene (POM). The moldings were performed with cavity pressure sensors in order to compare experimental process results with simulations. The warpage was characterized by measuring distances using a tactile coordinate measuring machine (CMM). Molding simulations have been executed taking into account actual processing conditions. Various aspects have been considered in the simulation: machine barrel geometry, injection speed profiles, cavity injection pressure, melt and mold temperatures, material rheological and pvT characterization. Factors investigated for comparisons were: injection pressure profile, short shots length, flow pattern, and warpage. A reliable molding experimental database was obtained, accurate simulations were conducted and a number of conclusions concerning improvements to simulation accuracy are presented regarding: pvT data, mesh, short shots, cavity pressure for process control validation as well as molding machine geometry modelling. Eventually, a methodology for improved molding simulations of cavity injection pressure, filling pattern and warpage was established.

  3. Comparing nonlinear MHD simulations of low-aspect-ratio RFPs to RELAX experiments

    NASA Astrophysics Data System (ADS)

    McCollam, K. J.; den Hartog, D. J.; Jacobson, C. M.; Sovinec, C. R.; Masamune, S.; Sanpei, A.

    2016-10-01

    Standard reversed-field pinch (RFP) plasmas provide a nonlinear dynamical system as a validation domain for numerical MHD simulation codes, with applications in general toroidal confinement scenarios including tokamaks. Using the NIMROD code, we simulate the nonlinear evolution of RFP plasmas similar to those in the RELAX experiment. The experiment's modest Lundquist numbers S (as low as a few times 104) make closely matching MHD simulations tractable given present computing resources. Its low aspect ratio ( 2) motivates a comparison study using cylindrical and toroidal geometries in NIMROD. We present initial results from nonlinear single-fluid runs at S =104 for both geometries and a range of equilibrium parameters, which preliminarily show that the magnetic fluctuations are roughly similar between the two geometries and between simulation and experiment, though there appear to be some qualitative differences in their temporal evolution. Runs at higher S are planned. This work is supported by the U.S. DOE and by the Japan Society for the Promotion of Science.

  4. Calibration of Chemical Kinetic Models Using Simulations of Small-Scale Cookoff Experiments

    SciTech Connect

    Wemhoff, A P; Becker, R C; Burnham, A K

    2008-02-26

    Establishing safe handling limits for explosives in elevated temperature environments is a difficult problem that often requires extensive simulation. The largest influence on predicting thermal cookoff safety lies in the chemical kinetic model used in these simulations, and these kinetic model reaction sequences often contain multiple steps. Several small-scale cookoff experiments, notably Differential Scanning Calorimetry (DSC), Thermogravimetric Analysis (TGA), One-Dimensional Time-to-Explosion (ODTX), and the Scaled Thermal Explosion (STEX) have been performed on various explosives to aid in cookoff behavior determination. Past work has used a single test from this group to create a cookoff model, which does not guarantee agreement with the other experiments. In this study, we update the kinetic parameters of an existing model for the common explosive 2,4,6-Trinitrotoluene (TNT) using DSC and ODTX experimental data at the same time by minimizing a global Figure of Merit based on hydrodynamic simulated data. We then show that the new kinetic model maintains STEX agreement, reduces DSC agreement, and improves ODTX and TGA agreement when compared to the original model. In addition, we describe a means to use implicit hydrodynamic simulations of DSC experiments to develop a reaction model for TNT melting.

  5. Probing the Action of Chemical Denaturant on an Intrinsically Disordered Protein by Simulation and Experiment.

    PubMed

    Zheng, Wenwei; Borgia, Alessandro; Buholzer, Karin; Grishaev, Alexander; Schuler, Benjamin; Best, Robert B

    2016-09-14

    Chemical denaturants are the most commonly used agents for unfolding proteins and are thought to act by better solvating the unfolded state. Improved solvation is expected to lead to an expansion of unfolded chains with increasing denaturant concentration, providing a sensitive probe of the denaturant action. However, experiments have so far yielded qualitatively different results concerning the effects of chemical denaturation. Studies using Förster resonance energy transfer (FRET) and other methods found an increase in radius of gyration with denaturant concentration, but most small-angle X-ray scattering (SAXS) studies found no change. This discrepancy therefore challenges our understanding of denaturation mechanism and more generally the accuracy of these experiments as applied to unfolded or disordered proteins. Here, we use all-atom molecular simulations to investigate the effect of urea and guanidinium chloride on the structure of the intrinsically disordered protein ACTR, which can be studied by experiment over a wide range of denaturant concentration. Using unbiased molecular simulations with a carefully calibrated denaturant model, we find that the protein chain indeed swells with increasing denaturant concentration. This is due to the favorable association of urea or guanidinium chloride with the backbone of all residues and with the side-chains of almost all residues, with denaturant-water transfer free energies inferred from this association in reasonable accord with experimental estimates. Interactions of the denaturants with the backbone are dominated by hydrogen bonding, while interactions with side-chains include other contributions. By computing FRET efficiencies and SAXS intensities at each denaturant concentration, we show that the simulation trajectories are in accord with both experiments on this protein, demonstrating that there is no fundamental inconsistency between the two types of experiment. Agreement with experiment also supports the

  6. Simulator for the Parity-Violating Deep Inelastic Scattering experiment in the Solenoidal Large Intensity Detector

    NASA Astrophysics Data System (ADS)

    Anderson, Jack; Hall A SoLID Collaboration

    2013-10-01

    The Solenoid Large Intensity Detector (SoLID) particle detector is the main detector that will be used for high energy particle experiments in Hall A that will be used with the 12 GeV electron beam at the Jefferson Lab. SoLID geometries were writen to be implemented in Geant4 using openGL as the visualization tool. This will allow us to test how the calorimeter, a specific yet integral part of the SoLID detector, detects the particles that result from electron beams colliding with targets. The goal is to simulate the approved experiments for the SoLID detector, starting with the Parity-Violating Deep Inelastic Scattering (PVDIS) experiment. This will provide critical information regarding the effectiveness of the calorimeter's design for such experiments. The expectation is that a Shashlik calorimeter will prove effective for the experiments approved for the SoLID detector. The ideal number of layers, or types of material for said layers, is an aspect of the calorimeter that will require testing through the simulations.The geometry files allow an easily-packaged program that can be shared amongst any collaborators interested in the SoLID experiments. NSF Grant No. 714001.

  7. Ionospheric Simulation System for Satellite Observations and Global Assimilative Modeling Experiments (ISOGAME)

    NASA Technical Reports Server (NTRS)

    Pi, Xiaoqing; Mannucci, Anthony J.; Verkhoglyadova, Olga P.; Stephens, Philip; Wilson, Brian D.; Akopian, Vardan; Komjathy, Attila; Lijima, Byron A.

    2013-01-01

    ISOGAME is designed and developed to assess quantitatively the impact of new observation systems on the capability of imaging and modeling the ionosphere. With ISOGAME, one can perform observation system simulation experiments (OSSEs). A typical OSSE using ISOGAME would involve: (1) simulating various ionospheric conditions on global scales; (2) simulating ionospheric measurements made from a constellation of low-Earth-orbiters (LEOs), particularly Global Navigation Satellite System (GNSS) radio occultation data, and from ground-based global GNSS networks; (3) conducting ionospheric data assimilation experiments with the Global Assimilative Ionospheric Model (GAIM); and (4) analyzing modeling results with visualization tools. ISOGAME can provide quantitative assessment of the accuracy of assimilative modeling with the interested observation system. Other observation systems besides those based on GNSS are also possible to analyze. The system is composed of a suite of software that combines the GAIM, including a 4D first-principles ionospheric model and data assimilation modules, an Internal Reference Ionosphere (IRI) model that has been developed by international ionospheric research communities, observation simulator, visualization software, and orbit design, simulation, and optimization software. The core GAIM model used in ISOGAME is based on the GAIM++ code (written in C++) that includes a new high-fidelity geomagnetic field representation (multi-dipole). New visualization tools and analysis algorithms for the OSSEs are now part of ISOGAME.

  8. Numerical simulations of lab-scale brine-water mixing experiments.

    SciTech Connect

    Khalil, Imane; Webb, Stephen Walter

    2006-10-01

    Laboratory-scale experiments simulating the injection of fresh water into brine in a Strategic Petroleum Reserve (SPR) cavern were performed at Sandia National Laboratories for various conditions of injection rate and small and large injection tube diameters. The computational fluid dynamic (CFD) code FLUENT was used to simulate these experiments to evaluate the predictive capability of FLUENT for brine-water mixing in an SPR cavern. The data-model comparisons show that FLUENT simulations predict the mixing plume depth reasonably well. Predictions of the near-wall brine concentrations compare very well with the experimental data. The simulated time for the mixing plume to reach the vessel wall was underpredicted for the small injection tubes but reasonable for the large injection tubes. The difference in the time to reach the wall is probably due to the three-dimensional nature of the mixing plume as it spreads out at the air-brine or oil-brine interface. The depth of the mixing plume as it spreads out along the interface was within a factor of 2 of the experimental data. The FLUENT simulation results predict the plume mixing accurately, especially the water concentration when the mixing plume reaches the wall. This parameter value is the most significant feature of the mixing process because it will determine the amount of enhanced leaching at the oil-brine interface.

  9. Experiment and hydro-mechanical coupling simulation study on the human periodontal ligament.

    PubMed

    Wei, Zhigang; Yu, Xiaoliu; Xu, Xiangrong; Chen, Xinyuan

    2014-03-01

    In this paper, a new method involving an experiment in vivo and hydro-mechanical coupling simulations was proposed to investigate the biomechanical property of human periodontal ligament (PDL). Teeth were loaded and their displacements were measured in vivo. The finite element model of the experiment was built and hydro-mechanical coupling simulations were conducted to test some PDL's constitutive models. In the simulations, the linear elastic model, the hyperfoam model, and the Ogden model were assumed for the solid phase of the PDL coupled with a model of the fluid phase of the PDL. The displacements of the teeth derived from the simulations were compared with the experimental data to validate these constitutive models. The study shows that a proposed constitutive model of the PDL can be reliably tested by this method. Furthermore, the influence of species, areas, and the fluid volume ratio on PDL's mechanical property should be considered in the modeling and simulation of the mechanical property of the PDL.

  10. Hybrid Reynolds-Averaged/Large-Eddy Simulations of a Coaxial Supersonic Free-Jet Experiment

    NASA Technical Reports Server (NTRS)

    Baurle, Robert A.; Edwards, Jack R.

    2010-01-01

    Reynolds-averaged and hybrid Reynolds-averaged/large-eddy simulations have been applied to a supersonic coaxial jet flow experiment. The experiment was designed to study compressible mixing flow phenomenon under conditions that are representative of those encountered in scramjet combustors. 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 initial 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 observed 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 Reynolds-averaged/large-eddy simulations also over-predicted the mixing layer spreading rate for the helium case, while under-predicting the rate of mixing when argon was used as the injectant. 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 were suggested as a remedy to this dilemma. Second-order turbulence statistics were also compared to their modeled Reynolds-averaged counterparts to evaluate the effectiveness of common turbulence closure

  11. Arginine in membranes: the connection between molecular dynamics simulations and translocon-mediated insertion experiments.

    PubMed

    Schow, Eric V; Freites, J Alfredo; Cheng, Philip; Bernsel, Andreas; von Heijne, Gunnar; White, Stephen H; Tobias, Douglas J

    2011-01-01

    Several laboratories have carried out molecular dynamics (MD) simulations of arginine interactions with lipid bilayers and found that the energetic cost of placing arginine in lipid bilayers is an order of magnitude greater than observed in molecular biology experiments in which Arg-containing transmembrane helices are inserted across the endoplasmic reticulum membrane by the Sec61 translocon. We attempt here to reconcile the results of the two approaches. We first present MD simulations of guanidinium groups alone in lipid bilayers, and then, to mimic the molecular biology experiments, we present simulations of hydrophobic helices containing single Arg residues at different positions along the helix. We discuss the simulation results in the context of molecular biology results and show that the energetic discrepancy is reduced, but not eliminated, by considering free energy differences between Arg at the interface and at the center of the model helices. The reduction occurs because Arg snorkeling to the interface prevents Arg from residing in the bilayer center where the energetic cost of desolvation is highest. We then show that the problem with MD simulations is that they measure water-to-bilayer free energies, whereas the molecular biology experiments measure the energetics of partitioning from translocon to bilayer, which raises the fundamental question of the relationship between water-to-bilayer and water-to-translocon partitioning. We present two thermodynamic scenarios as a foundation for reconciliation of the simulation and molecular biology results. The simplest scenario is that translocon-to-bilayer partitioning is independent of water-to-bilayer partitioning; there is no thermodynamic cycle connecting the two paths.

  12. Direct comparison of elastic incoherent neutron scattering experiments with molecular dynamics simulations of DMPC phase transitions.

    PubMed

    Aoun, Bachir; Pellegrini, Eric; Trapp, Marcus; Natali, Francesca; Cantù, Laura; Brocca, Paola; Gerelli, Yuri; Demé, Bruno; Marek Koza, Michael; Johnson, Mark; Peters, Judith

    2016-04-01

    Neutron scattering techniques have been employed to investigate 1,2-dimyristoyl-sn -glycero-3-phosphocholine (DMPC) membranes in the form of multilamellar vesicles (MLVs) and deposited, stacked multilamellar-bilayers (MLBs), covering transitions from the gel to the liquid phase. Neutron diffraction was used to characterise the samples in terms of transition temperatures, whereas elastic incoherent neutron scattering (EINS) demonstrates that the dynamics on the sub-macromolecular length-scale and pico- to nano-second time-scale are correlated with the structural transitions through a discontinuity in the observed elastic intensities and the derived mean square displacements. Molecular dynamics simulations have been performed in parallel focussing on the length-, time- and temperature-scales of the neutron experiments. They correctly reproduce the structural features of the main gel-liquid phase transition. Particular emphasis is placed on the dynamical amplitudes derived from experiment and simulations. Two methods are used to analyse the experimental data and mean square displacements. They agree within a factor of 2 irrespective of the probed time-scale, i.e. the instrument utilized. Mean square displacements computed from simulations show a comparable level of agreement with the experimental values, albeit, the best match with the two methods varies for the two instruments. Consequently, experiments and simulations together give a consistent picture of the structural and dynamical aspects of the main lipid transition and provide a basis for future, theoretical modelling of dynamics and phase behaviour in membranes. The need for more detailed analytical models is pointed out by the remaining variation of the dynamical amplitudes derived in two different ways from experiments on the one hand and simulations on the other.

  13. Simulations of supernova-relevant hydrodynamic instability experiments on the Nova laser

    NASA Astrophysics Data System (ADS)

    Kane, J.; Arnett, D.; Remington, B. A.; Glendinning, S. G.; Rubenchik, A.

    1997-11-01

    The critical roles of hydrodynamic instabilities in SN 1987A and in ICF are well known; 2D-3D differences are important in both areas. In a continuing project at Lawrence Livermore National Laboratory, the Nova Laser is being used in scaled laboratory experiments of hydrodynamic mixing under supernova-relevant conditions. Numerical simulations of the experiments are being done, using LLNL hydro codes, and astrophysics codes used to model supernovae. Initial investigations with two-layer planar packages having 2D sinusoidal interface perturbations are described in Ap.J. 478, L75 (1997). Early-time simulations done with the LLNL 1D radiation transport code HYADES are mapped into the 2D LLNL code CALE and into the multi-D supernova code PROMETHEUS. Work is underway on experiments comparing interface instability growth produced by 2D sinusoidal versus 3D cross-hatch and axisymmetric cylindrical perturbations. Results of the simulations will be presented and compared with experiment. Implications for interpreting supernova observations and for supernova modelling will be discussed. * Work performed under the auspices of the U.S. Department of Energy by the Lawrence Livermore National Laboratory under contract number W-7405-ENG-48.

  14. Colloidal Asphaltene Deposition and Aggregation in Capillary Flow: Experiments and Mesoscopic Simulation

    NASA Astrophysics Data System (ADS)

    Boek, Edo S.; Ladva, Hemant K.; Crawshaw, John P.; Padding, Johan T.

    2008-07-01

    The aggregation and deposition of colloidal asphaltene in reservoir rock is a significant problem in the oil industry. To obtain a fundamental understanding of this phenomenon, we have studied the deposition and aggregation of colloidal asphaltene in capillary flow by experiment and simulation. For the simulation, we have used the stochastic rotation dynamics (SRD) method, in which the solvent hydrodynamic emerges from the collisions between the solvent particles, while the Brownian motion emerges naturally from the interactions between the colloidal asphaltene particles and the solvent. The asphaltene colloids interact through a screened Coulomb potential. We vary the well depth ɛ∝ and the flow rate v to obtain Peflow≫1 (hydrodynamic interactions dominate) and Re≪1 (Stokes flow). In the simulations, we impose a pressure drop over the capillary length and measure the corresponding solvent flow rate. We observe that the transient solvent flow rate decreases when the asphaltene particles become more "sticky". For a well depth ɛ∝ = 2kBT, a monolayer deposits on the capillary wall. With an increasing well depth, the capillary becomes totally blocked. The clogging is transient for ɛ∝ = 5kBT, but appears to be permanent for ɛ∝ = 10-20 kBT. We compare our simulation results with flow experiments in glass capillaries, where we use extracted asphaltenes in toluene, reprecipitated with n-heptane. In the experiments, the dynamics of asphaltene precipitation and deposition were monitored in a slot capillary using optical microscopy under flow conditions similar to those used in the simulation. Maintaining a constant flow rate of 5 μL min-1, we found that the pressure drop across the capillary first increased slowly, followed by a sharp increase, corresponding to a complete local blockage of the capillary. Doubling the flow rate to 10 μL min-1, we observe that the initial deposition occurs faster but the deposits are subsequently entrained by the flow. We

  15. Foil Blanking Mechanism Research Using Rubber Tool by Finite Element Simulation and Experiment

    NASA Astrophysics Data System (ADS)

    Chen, Yang-Kai; Li, Xiao-Xing; Lang, Li-Hui; Xiao, Rui; Ge, Yu-Long

    2016-08-01

    For foil blanking process, the usage of flexible tool can effectively reduce the requirement of the manufacturing and assembling precision, compared with using conventional tool. However, the blanking mechanism using rubber tool is not clear. To investigate this question, the Finite Element (FE) model of rubber and process is established using ABAQUS package. The result of FE simulation affirm that the fracture emerges as a result of shear, not tensile. Then, for titanium foil with 0.08mm thickness, the cutting experiment is executed to verify the validity of blanking mechanism and FE simulation.

  16. Penetration of tungsten-alloy rods into composite ceramic targets: Experiments and 2-D simulations

    NASA Astrophysics Data System (ADS)

    Rosenberg, Z.; Dekel, E.; Hohler, V.; Stilp, A. J.; Weber, K.

    1998-07-01

    A series of terminal ballistics experiments, with scaled tungsten-alloy penetrators, was performed on composite targets consisting of ceramic tiles glued to thick steel backing plates. Tiles of silicon-carbide, aluminum nitride, titanium-dibroide and boron-carbide were 20-80 mm thick, and impact velocity was 1.7 km/s. 2-D numerical simulations, using the PISCES code, were performed in order to simulate these shots. It is shown that a simplified version of the Johnson-Holmquist failure model can account for the penetration depths of the rods but is not enough to capture the effect of lateral release waves on these penetrations.

  17. Variables Affecting Smooth Particle Hydrodynamics Simulation of High-Velocity Flyer Plate Impact Experiments

    SciTech Connect

    Somasundaram, Deepak S; Trabia, Mohamed; O'Toole, Brendan; Hixson, Robert S

    2014-01-23

    This paper describes our work to characterize the variables affecting the smoothed particle hydrodynamics (SPH) method in the LS-DYNA package for simulating high-velocity flyer plate impact experiments. LS-DYNA simulations are compared with one-dimensional experimental data of an oxygen-free high-conductivity (OFHC) copper flyer plate impacting another plate of the same material. The comparison is made by measuring the velocity of a point on the back surface of the impact plate using the velocity interferometer system for any reflector (VISAR) technique.

  18. Experiments and Simulations of Penetration into Granite by an Aluminum Shaped Charge

    SciTech Connect

    Murphy, M J; Randers-Pehrson, G; Kuklo, R M; Rambur, T A; Switzer, L L; Summes, M A

    2003-07-27

    This paper describes experimental results and numerical simulations of jet penetration into granite from an aluminum lined shaped charge. Several penetration versus standoff experiments were conducted into an in-situ granite formation located in the Climax Ridge region of the Nevada Test Site. Simulations of the jet penetration were modeled with a two dimensional arbitrary lagrange eulerian hydrocode. The effects of variations in the granite flow stress, porosity, and EOS have been evaluated. The work described in this paper is a continuation of our studies on jet penetration and modeling into high strength concrete.

  19. Tightly coupled long baseline/ultra-short baseline integrated navigation system

    NASA Astrophysics Data System (ADS)

    Batista, Pedro; Silvestre, Carlos; Oliveira, Paulo

    2016-06-01

    This paper proposes a novel integrated navigation filter based on a combined long baseline/ultra short baseline acoustic positioning system with application to underwater vehicles. With a tightly coupled structure, the position, linear velocity, attitude, and rate gyro bias are estimated, considering the full nonlinear system dynamics without resorting to any algebraic inversion or linearisation techniques. The resulting solution ensures convergence of the estimation error to zero for all initial conditions, exponentially fast. Finally, it is shown, under simulation environment, that the filter achieves very good performance in the presence of sensor noise.

  20. Atomistic resolution structure and dynamics of lipid bilayers in simulations and experiments.

    PubMed

    Ollila, O H Samuli; Pabst, Georg

    2016-10-01

    Accurate details on the sampled atomistic resolution structures of lipid bilayers can be experimentally obtained by measuring C-H bond order parameters, spin relaxation rates and scattering form factors. These parameters can be also directly calculated from the classical atomistic resolution molecular dynamics simulations (MD) and compared to the experimentally achieved results. This comparison measures the simulation model quality with respect to 'reality'. If agreement is sufficient, the simulation model gives an atomistic structural interpretation of the acquired experimental data. Significant advance of MD models is made by jointly interpreting different experiments using the same structural model. Here we focus on phosphatidylcholine lipid bilayers, which out of all model membranes have been studied mostly by experiments and simulations, leading to the largest available dataset. From the applied comparisons we conclude that the acyl chain region structure and rotational dynamics are generally well described in simulation models. Also changes with temperature, dehydration and cholesterol concentration are qualitatively correctly reproduced. However, the quality of the underlying atomistic resolution structural changes is uncertain. Even worse, when focusing on the lipid bilayer properties at the interfacial region, e.g. glycerol backbone and choline structures, and cation binding, many simulation models produce an inaccurate description of experimental data. Thus extreme care must be applied when simulations are applied to understand phenomena where the interfacial region plays a significant role. This work is done by the NMRlipids Open Collaboration project running at https://nmrlipids.blogspot.fi and https://github.com/NMRLipids. This article is part of a Special Issue entitled: Biosimulations edited by Ilpo Vattulainen and Tomasz Róg.