WorldWideScience

Sample records for simulating winter interactions

  1. Estimating winter survival of winter wheat by simulations of plant frost tolerance

    NARCIS (Netherlands)

    Bergjord Olsen, A.K.; Persson, T.; Wit, de A.; Nkurunziza, L.; Sindhøj, E.; Eckersten, H.

    2018-01-01

    Based on soil temperature, snow depth and the grown cultivar's maximum attainable level of frost tolerance (LT50c), the FROSTOL model simulates development of frost tolerance (LT50) and winter damage, thereby enabling risk calculations for winter wheat survival. To explore the accuracy of this

  2. Interactions between fungi colonizing the stem base of winter wheat

    Directory of Open Access Journals (Sweden)

    Urszula Wachowska

    2014-08-01

    Full Text Available In vitro conditions, the interactions betecen the fungi most frequently isolated from the stem base of winter wheat were determined. These were the species from genus Fusarium (F. culmorum, F. avenaceum and F. poae and Rhizoctonia cerealis, Pseudocercosporella herpotrichoides, Alternaria alternata and Aureobasidium bolleyi. Some saprotrophes showed stimulating effect on R. cerealis, P. herpotrichoides and F. poae. Certain species in combined cultures showed exceptionally favourable relationships.

  3. Simulating the impact of the entrainment of winter flounder larvae

    International Nuclear Information System (INIS)

    Hess, K.W.; Sissenwine, M.P.; Saila, S.B.

    1975-01-01

    The transport of winter flounder larvae around the Millstone Point, Conn. Area by the action of tidal currents and diffusion was simulated by computer to predict the numbers which could be entrained during the operation of a local nuclear power station. A tidal hydrodynamic model with variable depth was employed to simulate currents and water levels. These techniques provided input to a transport model which simulated the concentration of larvae. A larval source in a tributary river was simulated for twenty tidal cycles, with and without entrainment. The results indicated that the reduction in winter flounder larvae near Millstone Point at the end of the pelagic stage (period during which larvae are likely to be entrained) was less than 1 percent when it was assumed that larvae have little chance of returning once lost from Millstone bight. In order to assess the effect of a 1 percent reduction in recruitment of winter flounder larvae to the benthic phase of their life cycle, the local population was simulated by a model in which year-classes and the total egg production were represented by compartments. Each year-class grew, produced eggs, suffered natural and fishing mortality according to information derived from the literature. The effect of power plant entrainment was incorporated by reducing the number of recruits to year-class I that would normally result from a specific level of egg production. For a 1 percent reduction in recruitment due to power plant entrainment, a potential 6 percent decrease in total population size following 35 years of operation was indicated. (U.S.)

  4. Interactive Foresight Simulation

    DEFF Research Database (Denmark)

    Hansen, Mette Sanne; Rasmussen, Lauge Baungaard; Jacobsen, Peter

    2016-01-01

    The Combined Simulation Approach (CSA) is a way to evaluate risks and address potential unforeseen problems in a more interactive way than what is often observed in practice in companies or sectors. The approach is based on a combination of scenario analysis and discrete-event computer simulation...

  5. Intelligently interactive combat simulation

    Science.gov (United States)

    Fogel, Lawrence J.; Porto, Vincent W.; Alexander, Steven M.

    2001-09-01

    To be fully effective, combat simulation must include an intelligently interactive enemy... one that can be calibrated. But human operated combat simulations are uncalibratable, for we learn during the engagement, there's no average enemy, and we cannot replicate their culture/personality. Rule-based combat simulations (expert systems) are not interactive. They do not take advantage of unexpected mistakes, learn, innovate, and reflect the changing mission/situation. And it is presumed that the enemy does not have a copy of the rules, that the available experts are good enough, that they know why they did what they did, that their combat experience provides a sufficient sample and that we know how to combine the rules offered by differing experts. Indeed, expert systems become increasingly complex, costly to develop, and brittle. They have face validity but may be misleading. In contrast, intelligently interactive combat simulation is purpose- driven. Each player is given a well-defined mission, reference to the available weapons/platforms, their dynamics, and the sensed environment. Optimal tactics are discovered online and in real-time by simulating phenotypic evolution in fast time. The initial behaviors are generated randomly or include hints. The process then learns without instruction. The Valuated State Space Approach provides a convenient way to represent any purpose/mission. Evolutionary programming searches the domain of possible tactics in a highly efficient manner. Coupled together, these provide a basis for cruise missile mission planning, and for driving tank warfare simulation. This approach is now being explored to benefit Air Force simulations by a shell that can enhance the original simulation.

  6. Effects of dirty snow in nuclear winter simulations

    International Nuclear Information System (INIS)

    Vogelmann, A.M.; Robock, A.; Ellingson, R.G.

    1988-01-01

    A large-scale nuclear war would inject smoke into the atmosphere from burning forests, cities, and industries in targeted areas. This smoke could fall out onto snow and ice and would lower cryospheric albedos by as much as 50%. A global energy balance climate model is used to investigate the maximum effect these ''dirty snow'' albedos have on the surface temperature in nuclear winter simulations which span several years. These effects are investigated for different nuclear winter scenarios, snow precipitation rates, latitudinal distributions of smoke, and seasonal timings. We find that dirty snow, in general, would have a small temperature effect at mid- and low latitudes but could have a large temperature effect at polar latitudes, particularly if the soot is able to reappear significantly in later summers. Factors which limit the climatic importance of the dirty snow are (1) the dirty snow albedo is lowest when the atmosphere still contains a large amount of light-absorbing smoke; (2) even with dirty snow, sea ice areas can still increase, which helps maintain colder temperatures through the sea ice thermal inertial feedback; (3) the snow and ice areas affected by the dirty snow albedos are largest when there is little seasonal solar insolation; and (4) the area affected by the dirty snow is relatively small under all circumstances. copyright American Geophysical Union 1988

  7. Interactive Dynamic-System Simulation

    CERN Document Server

    Korn, Granino A

    2010-01-01

    Showing you how to use personal computers for modeling and simulation, Interactive Dynamic-System Simulation, Second Edition provides a practical tutorial on interactive dynamic-system modeling and simulation. It discusses how to effectively simulate dynamical systems, such as aerospace vehicles, power plants, chemical processes, control systems, and physiological systems. Written by a pioneer in simulation, the book introduces dynamic-system models and explains how software for solving differential equations works. After demonstrating real simulation programs with simple examples, the author

  8. Performance of Chlorella sorokiniana under simulated extreme winter conditions

    NARCIS (Netherlands)

    Cuaresma, M.; Buffing, M.F.; Janssen, M.G.J.; Lobato, C.V.; Wijffels, R.H.

    2012-01-01

    High annual microalgae productivities can only be achieved if solar light is efficiently used through the different seasons. During winter the productivity is low because of the light and temperature conditions. The productivity and photosynthetic efficiency of Chlorella sorokiniana were assessed

  9. Global characteristics of extreme winters from a multi-millennial simulation

    Energy Technology Data Exchange (ETDEWEB)

    Hunt, B.G. [CSIRO Marine and Atmospheric Research, PO Box 1, Aspendale (Australia)

    2011-10-15

    Output from a multi-millennial simulation with the CSIRO Mark 2 coupled global climatic model has been analysed to determine the principal characteristics of extreme winters over the globe for ''present conditions''. Thus, this study is not concerned with possible changes in winter conditions associated with anthropogenically induced climatic change. Defining an extreme winter as having a surface temperature anomaly of below -2 standard deviations (sd) revealed a general occurrence rate over the globe of between 100 and 200 over a 6,000-year period of the simulation, with somewhat higher values over northwest North America. For temperature anomalies below -3 sd the corresponding occurrence rate drops to about 10. Spatial correlation studies revealed that extreme winters over regions in Europe, North America or Asia were very limited geographically, with time series of the surface temperature anomalies for these regions having mutual correlation coefficients of about 0.2. The temporal occurrence rates of winters (summers) having sd below -3 (above +3) were very asymmetric and sporadic, suggesting that such events arise from stochastic influences. Multi-year sequences of extreme winters were comparatively rare events. Detailed analysis revealed that the temporal and spatial evolution of the monthly surface temperature anomalies associated with an individual extreme winter were well replicated in the simulation, as were daily time series of such anomalies. Apart from an influence of the North Atlantic Oscillation on extreme winters in Europe, other prominent climatic oscillations were very poorly correlated with such winters. Rather modest winter temperature anomalies were found in the southern hemisphere. (orig.)

  10. Interannual control of plankton communities by deep winter mixing and prey/predator interactions in the NW Mediterranean: Results from a 30-year 3D modeling study

    Science.gov (United States)

    Auger, P. A.; Ulses, C.; Estournel, C.; Stemmann, L.; Somot, S.; Diaz, F.

    2014-05-01

    A realistic modeling approach is designed to address the role of winter mixing on the interannual variability of plankton dynamics in the north-western (NW) Mediterranean basin. For the first time, a high-resolution coupled hydrodynamic-biogeochemical model (Eco3m-S) covering a 30-year period (1976-2005) is validated on available in situ and satellite data for the NW Mediterranean. In this region, cold, dry winds in winter often lead to deep convection and strong upwelling of nutrients into the euphotic layer. High nutrient contents at the end of winter then support the development of a strong spring bloom of phytoplankton. Model results indicate that annual primary production is not affected by winter mixing due to seasonal balance (minimum in winter and maximum in spring). However, the total annual water column-integrated phytoplankton biomass appears to be favored by winter mixing because zooplankton grazing activity is low in winter and early spring. This reduced grazing is explained here by the rarefaction of prey due to both light limitation and the effect of mixing-induced dilution on prey/predator interactions. A negative impact of winter mixing on winter zooplankton biomass is generally simulated except for mesozooplankton. This difference is assumed to stem from the lower parameterized mortality, top trophic position and detritivorous diet of mesozooplankton in the model. Moreover, model suggests that the variability of annual mesozooplankton biomass is principally modulated by the effects of winter mixing on winter biomass. Thus, interannual variability of winter nutrient contents in the euphotic layer, resulting from winter mixing, would control spring primary production and thus annual mesozooplankton biomass. Our results show a bottom-up control of mesozooplankton communities, as observed at a coastal location of the Ligurian Sea.

  11. Situational simulations in interactive video

    Energy Technology Data Exchange (ETDEWEB)

    Smith, L.J.

    1991-07-01

    The Westinghouse Hanford Company Advanced Training Technologies section is using situational simulations in several Interactive Video training courses. Two applications of situational simulations will be discussed. In the first, used in the Hanford General Employee Training course, the student evaluates employee's actions in simulations of possible workplace situations. In the second, used in the Criticality Safety course, students must follow well-defined procedures to complete tasks. Design and incorporation of situational simulations will be discussed. 3 refs.

  12. Situational simulations in interactive video

    International Nuclear Information System (INIS)

    Smith, L.J.

    1991-07-01

    The Westinghouse Hanford Company Advanced Training Technologies section is using situational simulations in several Interactive Video training courses. Two applications of situational simulations will be discussed. In the first, used in the Hanford General Employee Training course, the student evaluates employee's actions in simulations of possible workplace situations. In the second, used in the Criticality Safety course, students must follow well-defined procedures to complete tasks. Design and incorporation of situational simulations will be discussed. 3 refs

  13. Assessing winter cover crop nutrient uptake efficiency using a water quality simulation model

    Science.gov (United States)

    Yeo, In-Young; Lee, Sangchui; Sadeghi, Ali M.; Beeson, Peter C.; Hively, W. Dean; McCarty, Greg W.; Lang, Megan W.

    2013-01-01

    Winter cover crops are an effective conservation management practice with potential to improve water quality. Throughout the Chesapeake Bay Watershed (CBW), which is located in the Mid-Atlantic US, winter cover crop use has been emphasized and federal and state cost-share programs are available to farmers to subsidize the cost of winter cover crop establishment. The objective of this study was to assess the long-term effect of planting winter cover crops at the watershed scale and to identify critical source areas of high nitrate export. A physically-based watershed simulation model, Soil and Water Assessment Tool (SWAT), was calibrated and validated using water quality monitoring data and satellite-based estimates of winter cover crop species performance to simulate hydrological processes and nutrient cycling over the period of 1991–2000. Multiple scenarios were developed to obtain baseline information on nitrate loading without winter cover crops planted and to investigate how nitrate loading could change with different winter cover crop planting scenarios, including different species, planting times, and implementation areas. The results indicate that winter cover crops had a negligible impact on water budget, but significantly reduced nitrate leaching to groundwater and delivery to the waterways. Without winter cover crops, annual nitrate loading was approximately 14 kg ha−1, but it decreased to 4.6–10.1 kg ha−1 with winter cover crops resulting in a reduction rate of 27–67% at the watershed scale. Rye was most effective, with a potential to reduce nitrate leaching by up to 93% with early planting at the field scale. Early planting of winter cover crops (~30 days of additional growing days) was crucial, as it lowered nitrate export by an additional ~2 kg ha−1 when compared to late planting scenarios. The effectiveness of cover cropping increased with increasing extent of winter cover crop implementation. Agricultural fields with well-drained soils

  14. [Operation and interaction peculiarities of diagnostic laboratories involved in providing protection from infectious diseases during the XXII Olympic Winter Games and XI Paralympic Winter Games 2014 in Sochi].

    Science.gov (United States)

    Onishenko, G G; Popova, A Iu; Bragina, I V; Kuz'kin, B P; Ezhlova, E B; Demina, Iu V; Gus'kov, A S; Ivanov, G E; Chikina, L V; Klindukhova, V P; Grechanaia, T V; Tesheva, S Ch; Kulichenko, A N; Efremenko, D B; Manin, E A; Kuznetsova, I V; Parkhomenko, V V; Kulichenko, O A; Rafeenko, G K; Shcherbina, L I; Zavora, D L; Briukhanov, A F; Eldinova, V E; Iunicheva, Iu V; Derliatko, S K; Komarov, N S

    2015-01-01

    The experience of the organization and functioning of the laboratory network during the XXII Olympic Winter Games and XI Paralympic Winter Games of 2014 in Sochi is considered. Efforts to establish an effective system of laboratory support, the order of work and interaction of diagnostic laboratories involved in diseases control of population during the Olympic Games are analyzed.

  15. Simulating the influences of various fire regimes on caribou winter habitat

    Science.gov (United States)

    Rupp, T. Scott; Olson, Mark; Adams, Layne G.; Dale, Bruce W.; Joly, Kyle; Henkelman, Jonathan; Collins, William B.; Starfield, Anthony M.

    2006-01-01

    Caribou are an integral component of high‐latitude ecosystems and represent a major subsistence food source for many northern people. The availability and quality of winter habitat is critical to sustain these caribou populations. Caribou commonly use older spruce woodlands with adequate terrestrial lichen, a preferred winter forage, in the understory. Changes in climate and fire regime pose a significant threat to the long‐term sustainability of this important winter habitat. Computer simulations performed with a spatially explicit vegetation succession model (ALFRESCO) indicate that changes in the frequency and extent of fire in interior Alaska may substantially impact the abundance and quality of winter habitat for caribou. We modeled four different fire scenarios and tracked the frequency, extent, and spatial distribution of the simulated fires and associated changes to vegetation composition and distribution. Our results suggest that shorter fire frequencies (i.e., less time between recurring fires) on the winter range of the Nelchina caribou herd in eastern interior Alaska will result in large decreases of available winter habitat, relative to that currently available, in both the short and long term. A 30% shortening of the fire frequency resulted in a 3.5‐fold increase in the area burned annually and an associated 41% decrease in the amount of spruce–lichen forest found on the landscape. More importantly, simulations with more frequent fires produced a relatively immature forest age structure, compared to that which currently exists, with few stands older than 100 years. This age structure is at the lower limits of stand age classes preferred by caribou from the Nelchina herd. Projected changes in fire regime due to climate warming and/or additional prescribed burning could substantially alter the winter habitat of caribou in interior Alaska and lead to changes in winter range use and/or population dynamics.

  16. Numerical simulation of a rare winter hailstorm event over Delhi, India on 17 January 2013

    Science.gov (United States)

    Chevuturi, A.; Dimri, A. P.; Gunturu, U. B.

    2014-12-01

    This study analyzes the cause of the rare occurrence of a winter hailstorm over New Delhi/NCR (National Capital Region), India. The absence of increased surface temperature or low level of moisture incursion during winter cannot generate the deep convection required for sustaining a hailstorm. Consequently, NCR shows very few cases of hailstorms in the months of December-January-February, making the winter hail formation a question of interest. For this study, a recent winter hailstorm event on 17 January 2013 (16:00-18:00 UTC) occurring over NCR is investigated. The storm is simulated using the Weather Research and Forecasting (WRF) model with the Goddard Cumulus Ensemble (GCE) microphysics scheme with two different options: hail and graupel. The aim of the study is to understand and describe the cause of hailstorm event during over NCR with a comparative analysis of the two options of GCE microphysics. Upon evaluating the model simulations, it is observed that the hail option shows a more similar precipitation intensity with the Tropical Rainfall Measuring Mission (TRMM) observation than the graupel option does, and it is able to simulate hail precipitation. Using the model-simulated output with the hail option; detailed investigation on understanding the dynamics of hailstorm is performed. The analysis based on a numerical simulation suggests that the deep instability in the atmospheric column led to the formation of hailstones as the cloud formation reached up to the glaciated zone promoting ice nucleation. In winters, such instability conditions rarely form due to low level available potential energy and moisture incursion along with upper level baroclinic instability due to the presence of a western disturbance (WD). Such rare positioning is found to be lowering the tropopause with increased temperature gradient, leading to winter hailstorm formation.

  17. Numerical simulation of a winter hailstorm event over Delhi, India on 17 January 2013

    Science.gov (United States)

    Chevuturi, A.; Dimri, A. P.; Gunturu, U. B.

    2014-09-01

    This study analyzes the cause of rare occurrence of winter hailstorm over New Delhi/NCR (National Capital Region), India. The absence of increased surface temperature or low level of moisture incursion during winter cannot generate the deep convection required for sustaining a hailstorm. Consequently, NCR shows very few cases of hailstorms in the months of December-January-February, making the winter hail formation a question of interest. For this study, recent winter hailstorm event on 17 January 2013 (16:00-18:00 UTC) occurring over NCR is investigated. The storm is simulated using Weather Research and Forecasting (WRF) model with Goddard Cumulus Ensemble (GCE) microphysics scheme with two different options, hail or graupel. The aim of the study is to understand and describe the cause of hailstorm event during over NCR with comparative analysis of the two options of GCE microphysics. On evaluating the model simulations, it is observed that hail option shows similar precipitation intensity with TRMM observation than the graupel option and is able to simulate hail precipitation. Using the model simulated output with hail option; detailed investigation on understanding the dynamics of hailstorm is performed. The analysis based on numerical simulation suggests that the deep instability in the atmospheric column led to the formation of hailstones as the cloud formation reached upto the glaciated zone promoting ice nucleation. In winters, such instability conditions rarely form due to low level available potential energy and moisture incursion along with upper level baroclinic instability due to the presence of WD. Such rare positioning is found to be lowering the tropopause with increased temperature gradient, leading to winter hailstorm formation.

  18. Numerical simulation of a rare winter hailstorm event over Delhi, India on 17 January 2013

    KAUST Repository

    Chevuturi, A.

    2014-12-19

    This study analyzes the cause of the rare occurrence of a winter hailstorm over New Delhi/NCR (National Capital Region), India. The absence of increased surface temperature or low level of moisture incursion during winter cannot generate the deep convection required for sustaining a hailstorm. Consequently, NCR shows very few cases of hailstorms in the months of December-January-February, making the winter hail formation a question of interest. For this study, a recent winter hailstorm event on 17 January 2013 (16:00–18:00 UTC) occurring over NCR is investigated. The storm is simulated using the Weather Research and Forecasting (WRF) model with the Goddard Cumulus Ensemble (GCE) microphysics scheme with two different options: hail and graupel. The aim of the study is to understand and describe the cause of hailstorm event during over NCR with a comparative analysis of the two options of GCE microphysics. Upon evaluating the model simulations, it is observed that the hail option shows a more similar precipitation intensity with the Tropical Rainfall Measuring Mission (TRMM) observation than the graupel option does, and it is able to simulate hail precipitation. Using the model-simulated output with the hail option; detailed investigation on understanding the dynamics of hailstorm is performed. The analysis based on a numerical simulation suggests that the deep instability in the atmospheric column led to the formation of hailstones as the cloud formation reached up to the glaciated zone promoting ice nucleation. In winters, such instability conditions rarely form due to low level available potential energy and moisture incursion along with upper level baroclinic instability due to the presence of a western disturbance (WD). Such rare positioning is found to be lowering the tropopause with increased temperature gradient, leading to winter hailstorm formation.

  19. Application and Study of Precipitation Schemes in Weather Simulation in Summer and Winter over China

    Institute of Scientific and Technical Information of China (English)

    XU Guoqiang; WAN Qilin; HUANG Liping; XUE Jishan; CHEN Dehui

    2006-01-01

    Through simulation of summer and winter precipitation cases in China, the cloud precipitation schemes of model were examined. Results indicate that it is discrepant between convective precipitation simulated by the Kain-Fritsch (KF) scheme and Betts-Miller (BM) scheme in summer, the former scheme is better than the latter in this case. The ambient atmosphere may be varied by different convective schemes. The air is wetter and the updraft is stronger in the KF scheme than in the BM scheme, which can induce the more grid scale precipitation in the KF scheme, i.e., the different cumulus schemes may have the different and important effect on the grid scale precipitation. However, there is almost no convective rain in winter in northern China, so the effect of cumulus precipitation on the grid scale precipitation can be disregarded.Therefore, the gird scale precipitation is primary in the winter of northern China.

  20. Assessing winter cover crop nutrient uptake efficiency using a water quality simulation model

    Science.gov (United States)

    Yeo, I.-Y.; Lee, S.; Sadeghi, A. M.; Beeson, P. C.; Hively, W. D.; McCarty, G. W.; Lang, M. W.

    2014-12-01

    Winter cover crops are an effective conservation management practice with potential to improve water quality. Throughout the Chesapeake Bay watershed (CBW), which is located in the mid-Atlantic US, winter cover crop use has been emphasized, and federal and state cost-share programs are available to farmers to subsidize the cost of cover crop establishment. The objective of this study was to assess the long-term effect of planting winter cover crops to improve water quality at the watershed scale (~ 50 km2) and to identify critical source areas of high nitrate export. A physically based watershed simulation model, Soil and Water Assessment Tool (SWAT), was calibrated and validated using water quality monitoring data to simulate hydrological processes and agricultural nutrient cycling over the period of 1990-2000. To accurately simulate winter cover crop biomass in relation to growing conditions, a new approach was developed to further calibrate plant growth parameters that control the leaf area development curve using multitemporal satellite-based measurements of species-specific winter cover crop performance. Multiple SWAT scenarios were developed to obtain baseline information on nitrate loading without winter cover crops and to investigate how nitrate loading could change under different winter cover crop planting scenarios, including different species, planting dates, and implementation areas. The simulation results indicate that winter cover crops have a negligible impact on the water budget but significantly reduce nitrate leaching to groundwater and delivery to the waterways. Without winter cover crops, annual nitrate loading from agricultural lands was approximately 14 kg ha-1, but decreased to 4.6-10.1 kg ha-1 with cover crops resulting in a reduction rate of 27-67% at the watershed scale. Rye was the most effective species, with a potential to reduce nitrate leaching by up to 93% with early planting at the field scale. Early planting of cover crops (~ 30

  1. Air-sea interactions during strong winter extratropical storms

    Science.gov (United States)

    Nelson, Jill; He, Ruoying; Warner, John C.; Bane, John

    2014-01-01

    A high-resolution, regional coupled atmosphere–ocean model is used to investigate strong air–sea interactions during a rapidly developing extratropical cyclone (ETC) off the east coast of the USA. In this two-way coupled system, surface momentum and heat fluxes derived from the Weather Research and Forecasting model and sea surface temperature (SST) from the Regional Ocean Modeling System are exchanged via the Model Coupling Toolkit. Comparisons are made between the modeled and observed wind velocity, sea level pressure, 10 m air temperature, and sea surface temperature time series, as well as a comparison between the model and one glider transect. Vertical profiles of modeled air temperature and winds in the marine atmospheric boundary layer and temperature variations in the upper ocean during a 3-day storm period are examined at various cross-shelf transects along the eastern seaboard. It is found that the air–sea interactions near the Gulf Stream are important for generating and sustaining the ETC. In particular, locally enhanced winds over a warm sea (relative to the land temperature) induce large surface heat fluxes which cool the upper ocean by up to 2 °C, mainly during the cold air outbreak period after the storm passage. Detailed heat budget analyses show the ocean-to-atmosphere heat flux dominates the upper ocean heat content variations. Results clearly show that dynamic air–sea interactions affecting momentum and buoyancy flux exchanges in ETCs need to be resolved accurately in a coupled atmosphere–ocean modeling framework.

  2. Interactive Simulations of Biohybrid Systems

    Directory of Open Access Journals (Sweden)

    Sebastian Albrecht von Mammen

    2017-10-01

    Full Text Available In this article, we present approaches to interactive simulations of biohybrid systems. These simulations are comprised of two major computational components: (1 agent-based developmental models that retrace organismal growth and unfolding of technical scaffoldings and (2 interfaces to explore these models interactively. Simulations of biohybrid systems allow us to fast forward and experience their evolution over time based on our design decisions involving the choice, configuration and initial states of the deployed biological and robotic actors as well as their interplay with the environment. We briefly introduce the concept of swarm grammars, an agent-based extension of L-systems for retracing growth processes and structural artifacts. Next, we review an early augmented reality prototype for designing and projecting biohybrid system simulations into real space. In addition to models that retrace plant behaviors, we specify swarm grammar agents to braid structures in a self-organizing manner. Based on this model, both robotic and plant-driven braiding processes can be experienced and explored in virtual worlds. We present an according user interface for use in virtual reality. As we present interactive models concerning rather diverse description levels, we only ensured their principal capacity for interaction but did not consider efficiency analyzes beyond prototypic operation. We conclude this article with an outlook on future works on melding reality and virtuality to drive the design and deployment of biohybrid systems.

  3. Capstone Renaissance = Simulation + Interaction + DSS.

    Science.gov (United States)

    Jauch, Lawrence R.; And Others

    1989-01-01

    Reviews the development of integrated business policy and strategic management courses, or capstone courses, in business school curricula. A simulation game is described that incorporates the need for computer literacy, decision support systems (DSS), and interaction to effectively meet the needs for a capstone course. (14 references) (LRW)

  4. Effects of Wintering Environment and Parasite-Pathogen Interactions on Honey Bee Colony Loss in North Temperate Regions.

    Directory of Open Access Journals (Sweden)

    Suresh D Desai

    Full Text Available Extreme winter losses of honey bee colonies are a major threat to beekeeping but the combinations of factors underlying colony loss remain debatable. We monitored colonies in two environments (colonies wintered indoors or outdoors and characterized the effects of two parasitic mites, seven viruses, and Nosema on honey bee colony mortality and population loss over winter. Samples were collected from two locations within hives in fall, mid-winter and spring of 2009/2010. Although fall parasite and pathogen loads were similar in outdoor and indoor-wintered colonies, the outdoor-wintered colonies had greater relative reductions in bee population score over winter. Seasonal patterns in deformed wing virus (DWV, black queen cell virus (BQCV, and Nosema level also differed with the wintering environment. DWV and Nosema levels decreased over winter for indoor-wintered colonies but BQCV did not. Both BQCV and Nosema concentration increased over winter in outdoor-wintered colonies. The mean abundance of Varroa decreased and concentration of Sacbrood virus (SBV, Kashmir bee virus (KBV, and Chronic bee paralysis virus (CBPV increased over winter but seasonal patterns were not affected by wintering method. For most viruses, either entrance or brood area samples were reasonable predictors of colony virus load but there were significant season*sample location interactions for Nosema and BQCV, indicating that care must be taken when selecting samples from a single location. For Nosema spp., the fall entrance samples were better predictors of future infestation levels than were fall brood area samples. For indoor-wintered colonies, Israeli acute paralysis virus IAPV concentration was negatively correlated with spring population size. For outdoor-wintered hives, spring Varroa abundance and DWV concentration were positively correlated with bee loss and negatively correlated with spring population size. Multivariate analyses for fall collected samples indicated

  5. Winter Cover Crop Effects on Nitrate Leaching in Subsurface Drainage as Simulated by RZWQM-DSSAT

    Science.gov (United States)

    Malone, R. W.; Chu, X.; Ma, L.; Li, L.; Kaspar, T.; Jaynes, D.; Saseendran, S. A.; Thorp, K.; Yu, Q.

    2007-12-01

    Planting winter cover crops such as winter rye (Secale cereale L.) after corn and soybean harvest is one of the more promising practices to reduce nitrate loss to streams from tile drainage systems without negatively affecting production. Because availability of replicated tile-drained field data is limited and because use of cover crops to reduce nitrate loss has only been tested over a few years with limited environmental and management conditions, estimating the impacts of cover crops under the range of expected conditions is difficult. If properly tested against observed data, models can objectively estimate the relative effects of different weather conditions and agronomic practices (e.g., various N fertilizer application rates in conjunction with winter cover crops). In this study, an optimized winter wheat cover crop growth component was integrated into the calibrated RZWQM-DSSAT hybrid model and then we compare the observed and simulated effects of a winter cover crop on nitrate leaching losses in subsurface drainage water for a corn-soybean rotation with N fertilizer application rates over 225 kg N ha-1 in corn years. Annual observed and simulated flow-weighted average nitrate concentration (FWANC) in drainage from 2002 to 2005 for the cover crop treatments (CC) were 8.7 and 9.3 mg L-1 compared to 21.3 and 18.2 mg L-1 for no cover crop (CON). The resulting observed and simulated FWANC reductions due to CC were 59% and 49%. Simulations with the optimized model at various N fertilizer rates resulted in average annual drainage N loss differences between CC and CON to increase exponentially from 12 to 34 kg N ha-1 for rates of 11 to 261 kg N ha-1. The results suggest that RZWQM-DSSAT is a promising tool to estimate the relative effects of a winter crop under different conditions on nitrate loss in tile drains and that a winter cover crop can effectively reduce nitrate losses over a range of N fertilizer levels.

  6. Analysis of winter climate simulations performed with ARPEGE-Climat (T63) in the framework of PROVOST

    Energy Technology Data Exchange (ETDEWEB)

    Parey, S.; Dichampt-Martineu, Ch.; Caneill, J.Y. [Electricite de France, 78 - Chatou (France). Research Branch, Environment

    1997-12-01

    The interest of EDF for seasonal forecasting is a consequence of the high sensitivity of electricity consumption to temperature, especially during the winter season. That is why the Research branch of EDF is involved in the PROVOST project (PRediction Of climate Variations On Seasonal and inter-annual Timescales). Two sets of simulations are studied. The first one was calculated apart from the PROVOST experiments with the LMD model covering the 1970 to 1992 winters with eleven simulations per winter. The second one was calculated at EDF in the framework of PROVOST with ARPEGE-Climat model, covering the 1979 to 1994 winters (nine simulations per winter). The probabilistic formulation of climatic scenarios in function of the seasonal simulations with ARPEGE-Climat gives good results if the monthly mean temperature is taken into account. (R.P.) 3 refs.

  7. IOD influence on the early winter tibetan plateau snow cover: diagnostic analyses and an AGCM simulation

    Energy Technology Data Exchange (ETDEWEB)

    Yuan, Chaoxia; Tozuka, Tomoki; Yamagata, Toshio [The University of Tokyo, Department of Earth and Planetary Science, Graduate School of Science, Tokyo (Japan)

    2012-10-15

    Using diagnostic analyses and an AGCM simulation, the detailed mechanism of Indian Ocean Dipole (IOD) influence on the early winter Tibetan Plateau snow cover (EWTPSC) is clarified. In early winter of pure positive IOD years with no co-occurrence of El Nino, the anomalous dipole diabatic heating over the tropical Indian Ocean excites the baroclinic response in the tropics. Since both baroclinic and barotropic components of the basic zonal wind over the Arabian Peninsula increase dramatically in early winter due to the equatorward retreat of the westerly jet, the baroclinic mode excites the barotropic Rossby wave that propagates northeastward and induces a barotropic cyclonic anomaly north of India. This enables the moisture transport cyclonically from the northern Indian Ocean toward the Tibetan Plateau. The convergence of moisture over the plateau explains the positive influence of IOD on the EWTPSC. In contrast, the basic zonal wind over the Arabian Peninsula is weak in autumn. This is not favorable for excitation of the barotropic Rossby wave and teleconnection, even though the IOD-related diabatic heating anomaly in autumn similar to that in early winter exists. This result explains the insignificant (significant positive) partial correlation between IOD and the autumn (early winter) Tibetan Plateau snow cover after excluding the influence of ENSO. The sensitivity experiment forced by the IOD-related SST anomaly within the tropical Indian Ocean well reproduces the baroclinic response in the tropics, the teleconnection from the Arabian Peninsula, and the increased moisture supply to the Tibetan Plateau. Also, the seasonality of the atmospheric response to the IOD is simulated. (orig.)

  8. Winter precipitation and cyclones in the Mediterranean region: future climate scenarios in a regional simulation

    Directory of Open Access Journals (Sweden)

    P. Lionello

    2007-11-01

    Full Text Available Future climate projections show higher/lower winter (Dec-Jan-Feb precipitation in the northern/southern Mediterranean region than in present climate conditions. This paper analyzes the results of regional model simulations of the A2 and B2 scenarios, which confirm this opposite precipitation change and link it to the change of cyclone activity. The increase of the winter cyclone activity in future climate scenarios over western Europe is responsible for the larger precipitation at the northern coast of the basin, though the bulk of the change is located outside the Mediterranean region. The reduction of cyclone activity inside the Mediterranean region in future scenarios is responsible for the lower precipitation at the southern and eastern Mediterranean coast.

  9. Winter-to-winter variations in indoor radon

    International Nuclear Information System (INIS)

    Mose, D.G.; Mushrush, G.W.; Kline, S.W.

    1989-01-01

    Indoor radon concentrations in northern Virginia and central Maryland show a strong dependence on weather. Winter tends to be associated with higher than average indoor radon, and summer with lower than average. However, compared to the winter of 1986-1987, the winter of 1987-1988 was warmer and drier. Consequently, winter-to-winter indoor radon decreased by about 25%. This winter-to-winter decrease is unexpectedly large, and simulates winter-to-summer variations that have been reported

  10. Simulating the formation of carbonaceous aerosol in a European Megacity (Paris) during the Megapoli summer and winter campaigns

    NARCIS (Netherlands)

    Fountoukis, C.; Megaritis, A.G.; Skyllakou, K.; Charalampidis, P.E.; Denier van der Gon, H.A.C.; Crippa, M.; Prevot, A.S.H.; Fachinger, F.; Wiedensohler, A.; Pilinis, C.; Pandis, S.N.

    2016-01-01

    We use a three-dimensional regional chemical transport model (PMCAMx) with high grid resolution and high-resolution emissions (4 x 4 km2) over the Paris greater area to simulate the formation of carbonaceous aerosol dur-ing a summer (July 2009) and a winter (January/February 2010) period as part of

  11. Toward an Ontology of Simulated Social Interaction

    DEFF Research Database (Denmark)

    Seibt, Johanna

    2017-01-01

    and asymmetric modes of realizing Á, called the ‘simulatory expansion’ of interaction type Á. Simulatory expansions of social interactions can be used to map out different kinds and degrees of sociality in human-human and human-robot interaction, relative to current notions of sociality in philosophy......, anthropology, and linguistics. The classificatory framework developed (SISI) thus represents the field of possible simulated social interactions. SISI can be used to clarify which conceptual and empirical grounds we can draw on to evaluate capacities and affordances of robots for social interaction......The paper develops a general conceptual framework for the ontological classification of human-robot interaction. After arguing against fictionalist interpretations of human-robot interactions, I present five notions of simulation or partial realization, formally defined in terms of relationships...

  12. Assessing winter cover crop nutrient uptake efficiency using a water quality simulation model

    OpenAIRE

    Yeo, I.-Y.; Lee, S.; Sadeghi, A. M.; Beeson, P. C.; Hively, W. D.; McCarty, G. W.; Lang, M. W.

    2014-01-01

    Winter cover crops are an effective conservation management practice with potential to improve water quality. Throughout the Chesapeake Bay watershed (CBW), which is located in the mid-Atlantic US, winter cover crop use has been emphasized, and federal and state cost-share programs are available to farmers to subsidize the cost of cover crop establishment. The objective of this study was to assess the long-term effect of planting winter cover crops to improve water quality a...

  13. Salesperson Ethics: An Interactive Computer Simulation

    Science.gov (United States)

    Castleberry, Stephen

    2014-01-01

    A new interactive computer simulation designed to teach sales ethics is described. Simulation learner objectives include gaining a better understanding of legal issues in selling; realizing that ethical dilemmas do arise in selling; realizing the need to be honest when selling; seeing that there are conflicting demands from a salesperson's…

  14. Analysis of thematic mapper simulator data acquired during winter season over Pearl River, Mississippi, test site

    Science.gov (United States)

    Anderson, J. E.; Kalcic, M. T. (Principal Investigator)

    1982-01-01

    Digital processed aircraft-acquired thematic mapping simulator (TMS) data collected during the winter season over a forested site in southern Mississippi are presented to investigate the utility of TMS data for use in forest inventories and monitoring. Analyses indicated that TMS data are capable of delineating the mixed forest land cover type to an accuracy of 92.5 % correct. The accuracies associated with river bottom forest and pine forest were 95.5 and 91.5 % correct. The accuracies associated with river bottom forest and pine forest were 95.5 and 91.5 % correct, respectively. The figures reflect the performance for products produced using the best subset of channels for each forest cover type. It was found that the choice of channels (subsets) has a significant effect on the accuracy of classification produced, and that the same channels are not the most desirable for all three forest types studied. Both supervised and unsupervised spectral signature development techniques are evaluated; the unsupervised methods proved unacceptable for the three forest types considered.

  15. Simulation model for longterm management of Avena fatua L. in winter wheat

    Directory of Open Access Journals (Sweden)

    Jäck, Ortrud

    2014-02-01

    Full Text Available Decision support systems (DSS are used for weed control decisions worldwide. Several DSS for weed management have been published. However they mostly rely on full herbicide dosages and do not take weed population dynamics into account. We developed a modular DSS for long-term Avena fatua L. control in winter wheat. The DSS was parameterized with three year field experiment datasets covering yield loss data, densitydependent population dynamics data as well as data on dose dependent herbicide efficacy and dosedependent population dynamics. The DSS aims to control the A. fatua in the long run. Our hypothesis is that the optimized DSS reduces herbicide input while keeping the population density at low level, maintaining high grain yields and net return. The DSS comprises four sub-models calculating crop yield loss, A. fatua population dynamics as well as dose dependent herbicide efficacy and economics of the weed control decision. The economic sub-model calculates net return in dependency of the herbicide dosage and thus the resulting crop yield. First results of a 10-year simulation showed that herbicide input could be reduced by 40% compared to the economic threshold strategy, while the population density of A. fatua is controlled. Up to now the DSS has been parameterized for the herbicides Ralon Super, Axial 50 and Broadway. The results show the great potential of reducing herbicide input and point out the importance of including population dynamics models into DSS.

  16. Numerical simulation of ion-surface interactions

    International Nuclear Information System (INIS)

    Hou, M.

    1994-01-01

    This paper, based on examples from the author's contribution, aims to illustrate the role of ballistic simulations of the interaction between an ion beam and a surface in the characterization of surface properties. Several aspects of the ion-surface interaction have been modelled to various levels of sophistication by computer simulation. Particular emphasis is given to the ion scattering in the impact mode, in the multiple scattering regime and at grazing incidence, as well as to the Auger emission resulting from electronic excitation. Some examples are then given in order to illustrate the use of the combination between simulation and experiment to study the ion-surface interaction and surface properties. Ion-induced Auger emission, the determination of potentials and of overlay structures are discusse. The possibility to tackle dynamical surface properties by menas of a combination between molecular dynamics, ballistic simulations and ion scattering measurements in then briefly discussed. (orig.)

  17. Interactive simulation of technology management foresight

    DEFF Research Database (Denmark)

    Hansen, Mette Sanne; Rasmussen, Lauge Baungaard; Jacobsen, Peter

    2013-01-01

    of either qualitative or quantitative processes due to the complexity and uncertainty of the more or less interrelated technology tracks. Accordingly, the foresight approach must allow for interaction between the real-world system and the model builders, for example by using an interacting narrative...... is often occurring in companies. The use of CSA makes it possible for management to close the often experienced knowledge and activity gaps between the strategic, tactical and operational levels in a company. The outcome of developing and using CSA is a generic approach that enables the interaction between...... narrative simulation (scenarios) and numerical simulation. These interactive processes can take place on the strategic, tactical and operational levels of an organization and thus contribute to close the gaps that often exist between these levels. The combined foresight simulation approach is, however...

  18. Shock wave interaction with turbulence: Pseudospectral simulations

    International Nuclear Information System (INIS)

    Buckingham, A.C.

    1986-01-01

    Shock waves amplify pre-existing turbulence. Shock tube and shock wave boundary layer interaction experiments provide qualitative confirmation. However, shock pressure, temperature, and rapid transit complicate direct measurement. Computational simulations supplement the experimental data base and help isolate the mechanisms responsible. Simulations and experiments, particularly under reflected shock wave conditions, significantly influence material mixing. In these pseudospectral Navier-Stokes simulations the shock wave is treated as either a moving (tracked or fitted) domain boundary. The simulations assist development of code mix models. Shock Mach number and pre-existing turbulence intensity initially emerge as key parameters. 20 refs., 8 figs

  19. Investigating added value of regional climate modeling in North American winter storm track simulations

    Science.gov (United States)

    Poan, E. D.; Gachon, P.; Laprise, R.; Aider, R.; Dueymes, G.

    2018-03-01

    Extratropical Cyclone (EC) characteristics depend on a combination of large-scale factors and regional processes. However, the latter are considered to be poorly represented in global climate models (GCMs), partly because their resolution is too coarse. This paper describes a framework using possibilities given by regional climate models (RCMs) to gain insight into storm activity during winter over North America (NA). Recent past climate period (1981-2005) is considered to assess EC activity over NA using the NCEP regional reanalysis (NARR) as a reference, along with the European reanalysis ERA-Interim (ERAI) and two CMIP5 GCMs used to drive the Canadian Regional Climate Model—version 5 (CRCM5) and the corresponding regional-scale simulations. While ERAI and GCM simulations show basic agreement with NARR in terms of climatological storm track patterns, detailed bias analyses show that, on the one hand, ERAI presents statistically significant positive biases in terms of EC genesis and therefore occurrence while capturing their intensity fairly well. On the other hand, GCMs present large negative intensity biases in the overall NA domain and particularly over NA eastern coast. In addition, storm occurrence over the northwestern topographic regions is highly overestimated. When the CRCM5 is driven by ERAI, no significant skill deterioration arises and, more importantly, all storm characteristics near areas with marked relief and over regions with large water masses are significantly improved with respect to ERAI. Conversely, in GCM-driven simulations, the added value contributed by CRCM5 is less prominent and systematic, except over western NA areas with high topography and over the Western Atlantic coastlines where the most frequent and intense ECs are located. Despite this significant added-value on seasonal-mean characteristics, a caveat is raised on the RCM ability to handle storm temporal `seriality', as a measure of their temporal variability at a given

  20. New logistics protocols for distributed interactive simulation

    Science.gov (United States)

    Taylor, Darrin; Morrison, John; Katz, Warren; Felton, Erik; Herman, Deborah A.

    1995-06-01

    In today's environment, the transportation and maintenance of military forces is nearly as important as combat operations. Rapid deployment to regions of low-intensity conflict will become a very common training scenario for the U.S. military. Thus it is desirable to apply distributed simulation technology to train logistics personnel in their combat support roles. Currently, distributed interactive simulation (DIS) only contains rudimentary logistics protocols. This paper introduces new protocols designed to handle the logistics problem. The Newtonian protocol takes a physics-based approach to modeling interactions on the simulation network. This protocol consists of a family of protocol data units (PDUs) which are used to communicate forces in different circumstances. The protocol implements a small set of physical relations. This represents a flexible and general mechanism to describe battlefield interactions between network entities. The migratory object protocol (MOP) family addresses the transfer of control. General mechanisms provide the means to simulate resupply, repair, and maintenance of entities at any level of abstraction (individual soldier to division). It can also increase the fidelity of mine laying, enable handover of weapons for terminal guidance, allow for the distribution of aggregate-level simulation entities, provide capabilities for the simulation of personnel, etc.

  1. SIMULATION AND INVESTIGATION OF TIRE TREAD BLOCKS INTERACTION WITH ICE

    Directory of Open Access Journals (Sweden)

    Andrius Ružinskas

    2017-12-01

    Full Text Available The car tire is an essential subject analysing its interaction with the road. From tire’s tread condition, geometry and rubber compound depends grip and vehicle stability. This is especially relevant in winter time, when roads are covered with the layer of snow or ice. Generally, new tires are tested in real traffic conditions using vehicles. However, ensuring these conditions requires many resources and sometimes it could be a big challenge. For this reason, simulation of the tire interaction with the road becomes more important in nowadays tire researches. Since the tire is a complex engineering subject, the tire tread blocks could be separated for individual analysis. The interaction between the dry ice and the tread block with sipes was analysed using finite element analysis. The tread block was described using hyperelastic Mooney­Rivlin material model. The deformations, distribution of the contact pressure and shear stresses were obtained for the soft and hard rubber compounds with different vertical load conditions. Also a solid tread block interaction was analysed and it was found that values of contact pressure and shear stresses are much lower comparing to siped tread block.

  2. Interactive Mathematica Simulations in Chemical Engineering Courses

    Science.gov (United States)

    Falconer, John L.; Nicodemus, Garret D.

    2014-01-01

    Interactive Mathematica simulations with graphical displays of system behavior are an excellent addition to chemical engineering courses. The Manipulate command in Mathematica creates on-screen controls that allow users to change system variables and see the graphical output almost instantaneously. They can be used both in and outside class. More…

  3. Local simulation algorithms for Coulombic interactions

    Indian Academy of Sciences (India)

    We consider a problem in dynamically constrained Monte Carlo dynamics and show that this leads to the generation of long ranged effective interactions. This allows us to construct a local algorithm for the simulation of charged systems without ever having to evaluate pair potentials or solve the Poisson equation.

  4. Dynamic Interactions for Network Visualization and Simulation

    Science.gov (United States)

    2009-03-01

    projects.htm, Site accessed January 5, 2009. 12. John S. Weir, Major, USAF, Mediated User-Simulator Interactive Command with Visualization ( MUSIC -V). Master’s...Computing Sciences in Colleges, December 2005). 14. Enrique Campos -Nanez, “nscript user manual,” Department of System Engineer- ing University of

  5. Interactive Heat Transfer Simulations for Everyone

    Science.gov (United States)

    Xie, Charles

    2012-01-01

    Heat transfer is widely taught in secondary Earth science and physics. Researchers have identified many misconceptions related to heat and temperature. These misconceptions primarily stem from hunches developed in everyday life (though the confusions in terminology often worsen them). Interactive computer simulations that visualize thermal energy,…

  6. Interactive visualization to advance earthquake simulation

    Science.gov (United States)

    Kellogg, L.H.; Bawden, G.W.; Bernardin, T.; Billen, M.; Cowgill, E.; Hamann, B.; Jadamec, M.; Kreylos, O.; Staadt, O.; Sumner, D.

    2008-01-01

    The geological sciences are challenged to manage and interpret increasing volumes of data as observations and simulations increase in size and complexity. For example, simulations of earthquake-related processes typically generate complex, time-varying data sets in two or more dimensions. To facilitate interpretation and analysis of these data sets, evaluate the underlying models, and to drive future calculations, we have developed methods of interactive visualization with a special focus on using immersive virtual reality (VR) environments to interact with models of Earth's surface and interior. Virtual mapping tools allow virtual "field studies" in inaccessible regions. Interactive tools allow us to manipulate shapes in order to construct models of geological features for geodynamic models, while feature extraction tools support quantitative measurement of structures that emerge from numerical simulation or field observations, thereby enabling us to improve our interpretation of the dynamical processes that drive earthquakes. VR has traditionally been used primarily as a presentation tool, albeit with active navigation through data. Reaping the full intellectual benefits of immersive VR as a tool for scientific analysis requires building on the method's strengths, that is, using both 3D perception and interaction with observed or simulated data. This approach also takes advantage of the specialized skills of geological scientists who are trained to interpret, the often limited, geological and geophysical data available from field observations. ?? Birkhaueser 2008.

  7. Interactive methods for exploring particle simulation data

    Energy Technology Data Exchange (ETDEWEB)

    Co, Christopher S.; Friedman, Alex; Grote, David P.; Vay, Jean-Luc; Bethel, E. Wes; Joy, Kenneth I.

    2004-05-01

    In this work, we visualize high-dimensional particle simulation data using a suite of scatter plot-based visualizations coupled with interactive selection tools. We use traditional 2D and 3D projection scatter plots as well as a novel oriented disk rendering style to convey various information about the data. Interactive selection tools allow physicists to manually classify ''interesting'' sets of particles that are highlighted across multiple, linked views of the data. The power of our application is the ability to correspond new visual representations of the simulation data with traditional, well understood visualizations. This approach supports the interactive exploration of the high-dimensional space while promoting discovery of new particle behavior.

  8. An interactive beam position monitor system simulator

    International Nuclear Information System (INIS)

    Ryan, W.A.; Shea, T.J.

    1993-03-01

    A system simulator has been implemented to aid the development of the RHIC position monitor system. Based on the LabVIEW software package by National Instruments, this simulator allows engineers and technicians to interactively explore the parameter space of a system during the design phase. Adjustable parameters are divided into three categories: beam, pickup, and electronics. The simulator uses these parameters in simple formulas to produce results in both time-domain and frequencydomain. During the prototyping phase, these simulated results can be compared to test data acquired with the same software package. The RHIC position monitor system is presented as an example, but the software is applicable to several other systems as well

  9. Methodology for the interactive graphic simulator construction

    International Nuclear Information System (INIS)

    Milian S, Idalmis; Rodriguez M, Lazaro; Lopez V, Miguel A.

    1997-01-01

    The PC-supported Interactive Graphic Simulators (IGS) have successfully been used for industrial training programs in many countries. This paper is intended to illustrate the general methodology applied by our research team for the construction of this kind of conceptual or small scale simulators. The information and tools available to achieve this goal are also described. The applicability of the present methodology was confirmed with the construction of a set of IGS for nuclear power plants operators training programs in Cuba. One of them, relating reactor kinetics, is shown and briefly described in this paper. (author). 11 refs., 3 figs

  10. Simulations of light antinucleus-nucleus interactions

    Energy Technology Data Exchange (ETDEWEB)

    Galoyan, A., E-mail: galoyan@lxmx00.jinr.ru [JINR, LHEP (Russian Federation); Uzhinsky, V. [JINR, LIT (Russian Federation)

    2013-03-15

    Creations of light anti-nuclei (anti-deuterium, anti-tritium, anti-{sup 3}He and anti-{sup 4}He) are observed by collaborations at the LHC and RHIC accelerators. Some cosmic ray experiments are aimed to find the anti-nuclei in cosmic rays. To support the experimental studies of anti-nuclei a Monte Carlo simulation of anti-nuclei interactions with matter is implemented in the Geant4 toolkit. The implementation combines practically all known theoretical approaches to the problem of antinucleon-nucleon interactions.

  11. Simulation of Light Antinucleus-Nucleus Interactions

    CERN Document Server

    Galoyan, A.

    2013-01-01

    Creations of light anti-nuclei (anti-deuterium, anti-tritium, anti-He3 and anti-He4) are observed by collaborations at the LHC and RHIC accelerators. Some cosmic ray experiments are aimed to find the anti-nuclei in cosmic rays. To support the experimental studies of the anti-nuclei a Monte Carlo simulation of anti-nuclei interactions with matter is implemented in the Geant4 toolkit. The implementation combines practically all known theoretical approaches to the problem of antinucleon-nucleon interactions.

  12. Interactive monitoring portal for fusion simulations

    International Nuclear Information System (INIS)

    Abla, G.; Schissel, D.P.; Kim, E.N.; Flanagan, S.M.; Lee, X.

    2012-01-01

    Highlights: ► We designed a web-based monitoring system that tracks the status of fusion simulations. ► Our system is scalable to monitor the simulations running on distributed supercomputers and clusters located at multiple geographical locations. ► The monitoring portal provides a web-based interface for post-run analysis, such as visualizing the results, logging the user comments, and rating the simulation quality. ► Our system utilizes the open source software, such as Python, Django, MySQL, Apache, and MDSplus. - Abstract: The Center for Simulation of RF Wave Interactions with Magnetohydrodynamics (SWIM) Project is a proto-Fusion Simulation Program (FSP) whose goal is to study high-performance fusion plasmas and perform comprehensive simulations that are essential to the development of fusion. SWIM team members are geographically distributed and utilize distributed supercomputers for computational simulations. Due to the highly distributed computational work environment, the SWIM team has the difficulty of monitoring code runs and discovering historical runs. To alleviate this difficulty a web-based monitoring portal has been developed and deployed. The monitoring portal tracks the progress of simulations and automatically collects metadata in real-time. This capability helps scientists to effectively utilize precious computer resources. Furthermore, the portal provides a web-based interface for post-run analysis, such as visualizing the results, logging the user comments, and rating the simulation quality. The user interface provides rapid discovery capability via multi-field searching and sorting. The development of the monitoring portal used open source software, such as Python, Django, MySQL, and Apache. It uses MDSplus for data management, Memcached for data caches, and OpenID for single sign-on security. This paper describes the software architecture, related technologies and deployment experiences of the monitoring portal.

  13. Simulation of Wild oat (Avena ludoviciana L. Competition on Winter Wheat (Triticum astivum Growth and Yield. I: Model Description and Validation

    Directory of Open Access Journals (Sweden)

    F Mondani

    2015-09-01

    Full Text Available Crop growth models could stimulate growth and development based on science principles and mathematical equations. They also able to evaluate effects of climate, soil, water and agronomic management practices on crop yield. In the present study, an eco-physiological simulation model developed to assess wild oat damage to winter wheat growth and yield. The general structure of this model is derived from LINTUL1 model which modified to wild oat competition against winter wheat. LINTUL1 model was developed for simulation of spring wheat potential production level. In this study, first, we added development stage (DVS and vernalization to LINTUL1 for simulation of winter wheat growth and development and then the model calibrated for potential production level. Finally, we incorporate harmful effects of wild oat to winter wheat growth and yield. Weather data used as input were average daily minimum and maximum temperature (°C and daily global radiation (MJ m-2 in Mashhad, Iran. Parameter values were derived from the literature. The model is written in Fortran Simulation Translator (FST programming language and then validated based on an experiment data. For these purposes different wild oat plant densities were arranged. The data of this experiment does not use for calibration. The results showed that this model was in general able to simulate the temporal changes in DVS of winter wheat and wild oat, total dry matter (TDM of winter wheat and wild oat and yield loss of wheat due to wild oat competition in all treatments, satisfactorily. Root mean square error (RMSE for winter wheat DVS, wild oat DVS, average winter wheat TDM, average wild oat TDM, and yield loss of winter wheat was 10.4, 14.5, 5.8, 7.6 and 7.5, respectively.

  14. Interactive physically-based sound simulation

    Science.gov (United States)

    Raghuvanshi, Nikunj

    The realization of interactive, immersive virtual worlds requires the ability to present a realistic audio experience that convincingly compliments their visual rendering. Physical simulation is a natural way to achieve such realism, enabling deeply immersive virtual worlds. However, physically-based sound simulation is very computationally expensive owing to the high-frequency, transient oscillations underlying audible sounds. The increasing computational power of desktop computers has served to reduce the gap between required and available computation, and it has become possible to bridge this gap further by using a combination of algorithmic improvements that exploit the physical, as well as perceptual properties of audible sounds. My thesis is a step in this direction. My dissertation concentrates on developing real-time techniques for both sub-problems of sound simulation: synthesis and propagation. Sound synthesis is concerned with generating the sounds produced by objects due to elastic surface vibrations upon interaction with the environment, such as collisions. I present novel techniques that exploit human auditory perception to simulate scenes with hundreds of sounding objects undergoing impact and rolling in real time. Sound propagation is the complementary problem of modeling the high-order scattering and diffraction of sound in an environment as it travels from source to listener. I discuss my work on a novel numerical acoustic simulator (ARD) that is hundred times faster and consumes ten times less memory than a high-accuracy finite-difference technique, allowing acoustic simulations on previously-intractable spaces, such as a cathedral, on a desktop computer. Lastly, I present my work on interactive sound propagation that leverages my ARD simulator to render the acoustics of arbitrary static scenes for multiple moving sources and listener in real time, while accounting for scene-dependent effects such as low-pass filtering and smooth attenuation

  15. Interactive simulations for quantum key distribution

    International Nuclear Information System (INIS)

    Kohnle, Antje; Rizzoli, Aluna

    2017-01-01

    Secure communication protocols are becoming increasingly important, e.g. for internet-based communication. Quantum key distribution (QKD) allows two parties, commonly called Alice and Bob, to generate a secret sequence of 0s and 1s called a key that is only known to themselves. Classically, Alice and Bob could never be certain that their communication was not compromised by a malicious eavesdropper. Quantum mechanics however makes secure communication possible. The fundamental principle of quantum mechanics that taking a measurement perturbs the system (unless the measurement is compatible with the quantum state) also applies to an eavesdropper. Using appropriate protocols to create the key, Alice and Bob can detect the presence of an eavesdropper by errors in their measurements. As part of the QuVis Quantum Mechanics Visualisation Project, we have developed a suite of four interactive simulations that demonstrate the basic principles of three different QKD protocols. The simulations use either polarised photons or spin 1/2 particles as physical realisations. The simulations and accompanying activities are freely available for use online or download, and run on a wide range of devices including tablets and PCs. Evaluation with students over three years was used to refine the simulations and activities. Preliminary studies show that the refined simulations and activities help students learn the basic principles of QKD at both the introductory and advanced undergraduate levels. (paper)

  16. Interactive simulations for quantum key distribution

    Science.gov (United States)

    Kohnle, Antje; Rizzoli, Aluna

    2017-05-01

    Secure communication protocols are becoming increasingly important, e.g. for internet-based communication. Quantum key distribution (QKD) allows two parties, commonly called Alice and Bob, to generate a secret sequence of 0s and 1s called a key that is only known to themselves. Classically, Alice and Bob could never be certain that their communication was not compromised by a malicious eavesdropper. Quantum mechanics however makes secure communication possible. The fundamental principle of quantum mechanics that taking a measurement perturbs the system (unless the measurement is compatible with the quantum state) also applies to an eavesdropper. Using appropriate protocols to create the key, Alice and Bob can detect the presence of an eavesdropper by errors in their measurements. As part of the QuVis Quantum Mechanics Visualisation Project, we have developed a suite of four interactive simulations that demonstrate the basic principles of three different QKD protocols. The simulations use either polarised photons or spin 1/2 particles as physical realisations. The simulations and accompanying activities are freely available for use online or download, and run on a wide range of devices including tablets and PCs. Evaluation with students over three years was used to refine the simulations and activities. Preliminary studies show that the refined simulations and activities help students learn the basic principles of QKD at both the introductory and advanced undergraduate levels.

  17. Dynamics simulations for engineering macromolecular interactions

    Science.gov (United States)

    Robinson-Mosher, Avi; Shinar, Tamar; Silver, Pamela A.; Way, Jeffrey

    2013-01-01

    The predictable engineering of well-behaved transcriptional circuits is a central goal of synthetic biology. The artificial attachment of promoters to transcription factor genes usually results in noisy or chaotic behaviors, and such systems are unlikely to be useful in practical applications. Natural transcriptional regulation relies extensively on protein-protein interactions to insure tightly controlled behavior, but such tight control has been elusive in engineered systems. To help engineer protein-protein interactions, we have developed a molecular dynamics simulation framework that simplifies features of proteins moving by constrained Brownian motion, with the goal of performing long simulations. The behavior of a simulated protein system is determined by summation of forces that include a Brownian force, a drag force, excluded volume constraints, relative position constraints, and binding constraints that relate to experimentally determined on-rates and off-rates for chosen protein elements in a system. Proteins are abstracted as spheres. Binding surfaces are defined radially within a protein. Peptide linkers are abstracted as small protein-like spheres with rigid connections. To address whether our framework could generate useful predictions, we simulated the behavior of an engineered fusion protein consisting of two 20 000 Da proteins attached by flexible glycine/serine-type linkers. The two protein elements remained closely associated, as if constrained by a random walk in three dimensions of the peptide linker, as opposed to showing a distribution of distances expected if movement were dominated by Brownian motion of the protein domains only. We also simulated the behavior of fluorescent proteins tethered by a linker of varying length, compared the predicted Förster resonance energy transfer with previous experimental observations, and obtained a good correspondence. Finally, we simulated the binding behavior of a fusion of two ligands that could

  18. Balance sheet method assessment for nitrogen fertilization in winter wheat: II. alternative strategies using the CropSyst simulation model

    Directory of Open Access Journals (Sweden)

    Maria Corbellini

    2006-09-01

    Full Text Available It is important, both for farmer profit and for the environment, to correctly dose fertilizer nitrogen (N for winter wheat growth. Balance-sheet methods are often used to calculate the recommended dose of N fertilizer. Other methods are based on the dynamic simulation of cropping systems. Aim of the work was to evaluate the balance-sheet method set up by the Region Emilia-Romagna (DPI, by comparing it with the cropping systems simulation model CropSyst (CS, and with an approach based on fixed supplies of N (T. A 3-year trial was structured as a series of N fertility regimes at 3 sites (Papiano di Marsciano, Ravenna, San Pancrazio. The N-regimes were generated at each site-year as separate trials in which 3 N rates were applied: N1 (DPI, N2 (DPI+50 kg ha-1 N at spike initiation, N3 (DPI + 50 kg ha-1 N at early booting. Above ground biomass and soil data (NO3-N and water were sampled and used to calibrate CS. Doses of fertilizer N were calculated by both DPI and CS for winter wheat included in three typical rotations for Central and Northern Italy. Both these methods and method T were simulated at each site over 50 years, by using daily generated weather data. The long-term simulation allowed evaluating such alternative fertilization strategies. DPI and CS estimated comparable crop yields and N leached amounts, and both resulted better than T. Minor risk of leaching emerged for all N doses. The N2 and N3 rates allowed slightly higher crop yields than N1.

  19. Direct observations of atmosphere - sea ice - ocean interactions during Arctic winter and spring storms

    Science.gov (United States)

    Graham, R. M.; Itkin, P.; Granskog, M. A.; Assmy, P.; Cohen, L.; Duarte, P.; Doble, M. J.; Fransson, A.; Fer, I.; Fernandez Mendez, M.; Frey, M. M.; Gerland, S.; Haapala, J. J.; Hudson, S. R.; Liston, G. E.; Merkouriadi, I.; Meyer, A.; Muilwijk, M.; Peterson, A.; Provost, C.; Randelhoff, A.; Rösel, A.; Spreen, G.; Steen, H.; Smedsrud, L. H.; Sundfjord, A.

    2017-12-01

    To study the thinner and younger sea ice that now dominates the Arctic the Norwegian Young Sea ICE expedition (N-ICE2015) was launched in the ice-covered region north of Svalbard, from January to June 2015. During this time, eight local and remote storms affected the region and rare direct observations of the atmosphere, snow, ice and ocean were conducted. Six of these winter storms passed directly over the expedition and resulted in air temperatures rising from below -30oC to near 0oC, followed by abrupt cooling. Substantial snowfall prior to the campaign had already formed a snow pack of approximately 50 cm, to which the February storms contributed an additional 6 cm. The deep snow layer effectively isolated the ice cover and prevented bottom ice growth resulting in low brine fluxes. Peak wind speeds during winter storms exceeded 20 m/s, causing strong snow re-distribution, release of sea salt aerosol and sea ice deformation. The heavy snow load caused widespread negative freeboard; during sea ice deformation events, level ice floes were flooded by sea water, and at least 6-10 cm snow-ice layer was formed. Elevated deformation rates during the most powerful winter storms damaged the ice cover permanently such that the response to wind forcing increased by 60 %. As a result of a remote storm in April deformation processes opened about 4 % of the total area into leads with open water, while a similar amount of ice was deformed into pressure ridges. The strong winds also enhanced ocean mixing and increased ocean heat fluxes three-fold in the pycnocline from 4 to 12 W/m2. Ocean heat fluxes were extremely large (over 300 W/m2) during storms in regions where the warm Atlantic inflow is located close to surface over shallow topography. This resulted in very large (5-25 cm/day) bottom ice melt and in cases flooding due to heavy snow load. Storm events increased the carbon dioxide exchange between the atmosphere and ocean but also affected the pCO2 in surface waters

  20. Simulating the Interactions Among Land Use, Transportation ...

    Science.gov (United States)

    In most transportation studies, computer models that forecast travel behavior statistics for a future year use static projections of the spatial distribution of future population and employment growth as inputs. As a result, they are unable to account for the temporally dynamic and non-linear interactions among transportation, land use, and socioeconomic systems. System dynamics (SD) provides a common framework for modeling the complex interactions among transportation and other related systems. This study uses a SD model to simulate the cascading impacts of a proposed light rail transit (LRT) system in central North Carolina, USA. The Durham-Orange Light Rail Project (D-O LRP) SD model incorporates relationships among the land use, transportation, and economy sectors to simulate the complex feedbacks that give rise to the travel behavior changes forecasted by the region’s transportation model. This paper demonstrates the sensitivity of changes in travel behavior to the proposed LRT system and the assumptions that went into the transportation modeling, and compares those results to the impacts of an alternative fare-free transit system. SD models such as the D-O LRP SD model can complement transportation studies by providing valuable insight into the interdependent community systems that collectively contribute to travel behavior changes. Presented at the 35th International Conference of the System Dynamics Society in Cambridge, MA, July 18th, 2017

  1. System simulation for an untreated sewage source heat pump (USSHP) in winter

    Science.gov (United States)

    Qin, Na; Hao, Peng Z.

    2017-01-01

    The paper discusses the system characteristics of an untreated sewage source heat pump in winter. In this system, the sewage enters into the evaporator directly. The variable parameters to control the system contain the sewage temperature at evaporator inlet and the water temperature at condenser inlet. It is found that most parameters, except the condensation heat transfer coefficient, change in the form of sine wave the same as the sewage temperature at inlet. The heating load and consumed power are 12.9kW and 3.45kW when the sewage temperature at inlet is 13°C. COP is about 3.75 in the range of the sewage temperature at inlet of 12-13°C.

  2. 1973 Winter Simulation Conference. Sponsored by ACM/AIIE/SHARE/SCi/TIMS.

    Science.gov (United States)

    Hoggatt, Austin Curwood, Ed.

    A record of the current state of the art of simulation and the major part it now plays in policy formation in large organizations is provided by these conference proceedings. The 40 papers presented reveal an emphasis on the applications of simulation. In addition, the abstracts of 28 papers submitted to a more informal "paper fair" are also…

  3. Improvement in Simulation of Eurasian Winter Climate Variability with a Realistic Arctic Sea Ice Condition in an Atmospheric GCM

    Science.gov (United States)

    Lim, Young-Kwon; Ham, Yoo-Geun; Jeong, Jee-Hoon; Kug, Jong-Seong

    2012-01-01

    The present study investigates how much a realistic Arctic sea ice condition can contribute to improve simulation of the winter climate variation over the Eurasia region. Model experiments are set up using different sea ice boundary conditions over the past 24 years (i.e., 1988-2011). One is an atmospheric model inter-comparison (AMIP) type of run forced with observed sea-surface temperature (SST), sea ice, and greenhouse gases (referred to as Exp RSI), and the other is the same as Exp RSI except for the sea ice forcing, which is a repeating climatological annual cycle (referred to as Exp CSI). Results show that Exp RSI produces the observed dominant pattern of Eurasian winter temperatures and their interannual variation better than Exp CSI (correlation difference up to approx. 0.3). Exp RSI captures the observed strong relationship between the sea ice concentration near the Barents and Kara seas and the temperature anomaly across Eurasia, including northeastern Asia, which is not well captured in Exp CSI. Lagged atmospheric responses to sea ice retreat are examined using observations to understand atmospheric processes for the Eurasian cooling response including the Arctic temperature increase, sea-level pressure increase, upper-level jet weakening and cold air outbreak toward the mid-latitude. The reproducibility of these lagged responses by Exp RSI is also evaluated.

  4. Improvement in simulation of Eurasian winter climate variability with a realistic Arctic sea ice condition in an atmospheric GCM

    International Nuclear Information System (INIS)

    Lim, Young-Kwon; Ham, Yoo-Geun; Jeong, Jee-Hoon; Kug, Jong-Seong

    2012-01-01

    The present study investigates how much a realistic Arctic sea ice condition can contribute to improve simulation of the winter climate variation over the Eurasia region. Model experiments are set up using different sea ice boundary conditions over the past 24 years (i.e., 1988–2011). One is an atmospheric model inter-comparison (AMIP) type of run forced with observed sea-surface temperature (SST), sea ice, and greenhouse gases (referred to as Exp RSI), and the other is the same as Exp RSI except for the sea ice forcing, which is a repeating climatological annual cycle (referred to as Exp CSI). Results show that Exp RSI produces the observed dominant pattern of Eurasian winter temperatures and their interannual variation better than Exp CSI (correlation difference up to ∼0.3). Exp RSI captures the observed strong relationship between the sea ice concentration near the Barents and Kara seas and the temperature anomaly across Eurasia, including northeastern Asia, which is not well captured in Exp CSI. Lagged atmospheric responses to sea ice retreat are examined using observations to understand atmospheric processes for the Eurasian cooling response including the Arctic temperature increase, sea-level pressure increase, upper-level jet weakening and cold air outbreak toward the mid-latitude. The reproducibility of these lagged responses by Exp RSI is also evaluated. (letter)

  5. Computer simulation of spacecraft/environment interaction

    International Nuclear Information System (INIS)

    Krupnikov, K.K.; Makletsov, A.A.; Mileev, V.N.; Novikov, L.S.; Sinolits, V.V.

    1999-01-01

    This report presents some examples of a computer simulation of spacecraft interaction with space environment. We analysed a set data on electron and ion fluxes measured in 1991-1994 on geostationary satellite GORIZONT-35. The influence of spacecraft eclipse and device eclipse by solar-cell panel on spacecraft charging was investigated. A simple method was developed for an estimation of spacecraft potentials in LEO. Effects of various particle flux impact and spacecraft orientation are discussed. A computer engineering model for a calculation of space radiation is presented. This model is used as a client/server model with WWW interface, including spacecraft model description and results representation based on the virtual reality markup language

  6. Computer simulation of spacecraft/environment interaction

    CERN Document Server

    Krupnikov, K K; Mileev, V N; Novikov, L S; Sinolits, V V

    1999-01-01

    This report presents some examples of a computer simulation of spacecraft interaction with space environment. We analysed a set data on electron and ion fluxes measured in 1991-1994 on geostationary satellite GORIZONT-35. The influence of spacecraft eclipse and device eclipse by solar-cell panel on spacecraft charging was investigated. A simple method was developed for an estimation of spacecraft potentials in LEO. Effects of various particle flux impact and spacecraft orientation are discussed. A computer engineering model for a calculation of space radiation is presented. This model is used as a client/server model with WWW interface, including spacecraft model description and results representation based on the virtual reality markup language.

  7. Tyrosine transport in winter flounder intestine: Interaction with Na+-K+-2Cl- cotransport

    International Nuclear Information System (INIS)

    Musch, M.W.; McConnell, F.M.; Goldstein, L.; Field, M.

    1987-01-01

    Tyrosine absorption across the brush border of the intestinal epithelium of the winter flounder Pseudopleuronectes americanus was studied in Ussing chambers modified to determine early rates of uptake. At 0.1 mM tyrosine, the 4-min rate of uptake (influx) of tyrosine across the brush border averaged 37.5 nmol·cm -2 ·h -1 . Omission of Na decreased influx by 60%, indicting that tyrosine influx occurs, at least in part, by a Na-coupled process. Ouabain inhibited influx by 80%. Inhibition of brush border Na + -K + -2Cl - cotransport by bumetanide, 8-bromo-cyclic GMP, or Cl replacement stimulated tyrosine influx 2.5- to 4-fold. However, atriopeptin III, which also inhibits Na + -K + -2Cl - cotransport, did not stimulate tyrosine influx. Cyclic AMP, which does not appear to inhibit ion cotransport, did not stimulate tyrosine influx. Both cyclic GMP and bumetanide also stimulated the net mucosa-to-serosa tyrosine flux (43 and 29%, respectively) and increased the cellular concentration of tyrosine by 50%. Thus tyrosine's influx is increased to a greater extent than is its transmural flux or its cellular concentration, suggesting that the main change occurs at the brush border and represents large increases in both influx and efflux of tyrosine across this membrane

  8. Accounting for anthropic energy flux of traffic in winter urban road surface temperature simulations with TEB model

    Science.gov (United States)

    Khalifa, A.; Marchetti, M.; Bouilloud, L.; Martin, E.; Bues, M.; Chancibaut, K.

    2015-06-01

    A forecast of the snowfall helps winter coordination operating services, reducing the cost of the maintenance actions, and the environmental impacts caused by an inappropriate use of de-icing. In order to determine the possible accumulation of snow on pavement, the forecast of the road surface temperature (RST) is mandatory. Physical numerical models provide such forecast, and do need an accurate description of the infrastructure along with meteorological parameters. The objective of this study was to build a reliable urban RST forecast with a detailed integration of traffic in the Town Energy Balance (TEB) numerical model for winter maintenance. The study first consisted in generating a physical and consistent description of traffic in the model with all the energy interactions, with two approaches to evaluate the traffic incidence on RST. Experiments were then conducted to measure the traffic effect on RST increase with respect to non circulated areas. These field data were then used for comparison with forecast provided by this traffic-implemented TEB version.

  9. Properties and toxicological effects of particles from the interaction between tyres, road pavement and winter traction material

    Energy Technology Data Exchange (ETDEWEB)

    Gustafsson, Mats [Swedish National Road and Transport Research Institute (VTI), SE-581 95 Linkoeping (Sweden)], E-mail: mats.gustafsson@vti.se; Blomqvist, Goeran [Swedish National Road and Transport Research Institute (VTI), SE-581 95 Linkoeping (Sweden); Gudmundsson, Anders; Dahl, Andreas [Division of Ergonomics and Aerosol Technology, Department of Design Sciences, Lund University, P.O. Box 118, SE-221 00 Lund (Sweden); Swietlicki, Erik [Division of Nuclear Physics, Department of Physics, Lund University, P.O. Box 118, SE-221 00 Lund (Sweden); Bohgard, Mats [Division of Ergonomics and Aerosol Technology, Department of Design Sciences, Lund University, P.O. Box 118, SE-221 00 Lund (Sweden); Lindbom, John; Ljungman, Anders [Faculty of Health Sciences, Department of Molecular and Clinical Medicine, Division of Occupational and Environmental Medicine, SE-581 85 Linkoeping (Sweden)

    2008-04-15

    In regions where studded tyres and traction material are used during winter, e.g. the Nordic countries, northern part of USA, Canada, and Japan, mechanically generated particles from traffic are the main reason for high particle mass concentrations in busy street and road environments. In many Nordic municipalities the European environmental quality standard for inhalable particles (PM{sub 10}) is exceeded due to these particles. In this study, particles from the wear of studded and studless friction tyres on two pavements and traction sanding were generated using a road simulator. The particles were characterized using particle sizers, Particle Induced X-Ray Emission Analysis and electron microscopy. Cell studies were conducted on particles sampled from the tests with studded tyres and compared with street environment, diesel exhaust and subway PM{sub 10}, respectively. The results show that in the road simulator, where resuspension is minimized, studded tyres produce tens of times more particles than friction tyres. Chemical analysis of the sampled particles shows that the generated wear particles consist almost entirely of minerals from the pavement stone material, but also that Sulfur is enriched for the submicron particles and that Zink is enriched for friction tyres for all particles sizes. The chemical data can be used for source identification and apportionment in urban aerosol studies. A mode of ultra-fine particles was also present and is hypothesised to originate in the tyres. Further, traction material properties affect PM{sub 10} emission. The inflammatory potential of the particles from wear of pavements seems to depend on type of pavement and can be at least as potent as diesel exhaust particles. The results imply that there is a need and a good potential to reduce particle emission from pavement wear and winter time road and street operation by adjusting both studded tyre use as well as pavement and traction material properties.

  10. Properties and toxicological effects of particles from the interaction between tyres, road pavement and winter traction material

    International Nuclear Information System (INIS)

    Gustafsson, Mats; Blomqvist, Goeran; Gudmundsson, Anders; Dahl, Andreas; Swietlicki, Erik; Bohgard, Mats; Lindbom, John; Ljungman, Anders

    2008-01-01

    In regions where studded tyres and traction material are used during winter, e.g. the Nordic countries, northern part of USA, Canada, and Japan, mechanically generated particles from traffic are the main reason for high particle mass concentrations in busy street and road environments. In many Nordic municipalities the European environmental quality standard for inhalable particles (PM 10 ) is exceeded due to these particles. In this study, particles from the wear of studded and studless friction tyres on two pavements and traction sanding were generated using a road simulator. The particles were characterized using particle sizers, Particle Induced X-Ray Emission Analysis and electron microscopy. Cell studies were conducted on particles sampled from the tests with studded tyres and compared with street environment, diesel exhaust and subway PM 10 , respectively. The results show that in the road simulator, where resuspension is minimized, studded tyres produce tens of times more particles than friction tyres. Chemical analysis of the sampled particles shows that the generated wear particles consist almost entirely of minerals from the pavement stone material, but also that Sulfur is enriched for the submicron particles and that Zink is enriched for friction tyres for all particles sizes. The chemical data can be used for source identification and apportionment in urban aerosol studies. A mode of ultra-fine particles was also present and is hypothesised to originate in the tyres. Further, traction material properties affect PM 10 emission. The inflammatory potential of the particles from wear of pavements seems to depend on type of pavement and can be at least as potent as diesel exhaust particles. The results imply that there is a need and a good potential to reduce particle emission from pavement wear and winter time road and street operation by adjusting both studded tyre use as well as pavement and traction material properties

  11. Simulation of Relationship between ENSO and winter precipitation over Western Himalayas: Application of Regional climate model (RegT-Band)

    Science.gov (United States)

    Tiwari, P. R.; Mohanty, U. C.; Dey, S.; Acharaya, N.; Sinha, P.

    2012-12-01

    Precipitation over the Western Himalayas region during winter is mainly associated with the passage of midlatitude synoptic systems known as western disturbances (WDs). Recently, many observational and modeling studies reported that the relationship of the Indian southwest monsoon rainfall with El Niño- Southern Oscillation (ENSO) has weakened since around 1980. But, in contrast, only very few observational studies are reported so far to examine the relationship between ENSO and the winter precipitation over the Western Himalayas region from December to February (DJF). But there is a huge gap of modeling this phenomenon. So keeping in view of the absence of modeling studies, an attempt is made to simulate the relationship between wintertime precipitations associated with large scale global forcing of ENSO over the Western Himalayas. In the present study, RegT-Band, a tropical band version of the regional climate model RegCM4 is integrated for a set of 5 El Niño (1986-87, 1991-92, 1997-98, 2002-03, 2009-10) and 4 La Niña (1984-85, 1988-89, 1999-2000, 2007-08) years with the observed sea-surface temperature and lateral boundary condition. The domain extends from 50° S to 50° N and covers the entire tropics at a grid spacing of about 45 km, i.e. it includes lateral boundary forcing only at the southern and northern boundaries. The performance evaluation of the model in capturing the large scale fields followed by ENSO response with wintertime precipitation over the Western Himalayas region has been carried out by using National Center for Environmental Prediction (NCEP)-Department of Energy (DOE) reanalysis 2 (NNRP2) data (2.5° x 2.5°) and Aphrodite precipitation data (0.25° x 0.25°). The model is able to delineate the mean circulation associated with ENSO over the region during DJF reasonably well and shows strong southwesterly to northwesterly wind flow, which is there in verification analysis also. The vertical structure of the low as well as upper level

  12. Evaluation of air-soil temperature relationships simulated by land surface models during winter across the permafrost region

    Science.gov (United States)

    Wang, Wenli; Rinke, Annette; Moore, John C.; Ji, Duoying; Cui, Xuefeng; Peng, Shushi; Lawrence, David M.; McGuire, A. David; Burke, Eleanor J.; Chen, Xiaodong; Delire, Christine; Koven, Charles; MacDougall, Andrew; Saito, Kazuyuki; Zhang, Wenxin; Alkama, Ramdane; Bohn, Theodore J.; Ciais, Philippe; Decharme, Bertrand; Gouttevin, Isabelle; Hajima, Tomohiro; Krinner, Gerhard; Lettenmaier, Dennis P.; Miller, Paul A.; Smith, Benjamin; Sueyoshi, Tetsuo

    2016-01-01

     A realistic simulation of snow cover and its thermal properties are important for accurate modelling of permafrost. We analyze simulated relationships between air and near-surface (20 cm) soil temperatures in the Northern Hemisphere permafrost region during winter, with a particular focus on snow insulation effects in nine land surface models and compare them with observations from 268 Russian stations. There are large across-model differences as expressed by simulated differences between near-surface soil and air temperatures, (ΔT), of 3 to 14 K, in the gradients between soil and air temperatures (0.13 to 0.96°C/°C), and in the relationship between ΔT and snow depth. The observed relationship between ΔT and snow depth can be used as a metric to evaluate the effects of each model's representation of snow insulation, and hence guide improvements to the model’s conceptual structure and process parameterizations. Models with better performance apply multi-layer snow schemes and consider complex snow processes. Some models show poor performance in representing snow insulation due to underestimation of snow depth and/or overestimation of snow conductivity. Generally, models identified as most acceptable with respect to snow insulation simulate reasonable areas of near-surface permafrost (12–16 million km2). However, there is not a simple relationship between the quality of the snow insulation in the acceptable models and the simulated area of Northern Hemisphere near-surface permafrost, likely because several other factors such as differences in the treatment of soil organic matter, soil hydrology, surface energy calculations, and vegetation also provide important controls on simulated permafrost distribution.

  13. Numerical simulation of a rare winter hailstorm event over Delhi, India on 17 January 2013

    KAUST Repository

    Chevuturi, A.; Dimri, A. P.; Gunturu, Udaya

    2014-01-01

    January 2013 (16:00–18:00 UTC) occurring over NCR is investigated. The storm is simulated using the Weather Research and Forecasting (WRF) model with the Goddard Cumulus Ensemble (GCE) microphysics scheme with two different options: hail and graupel

  14. Effects of Zn, macronutrients, and their interactions through foliar applications on winter wheat grain nutritional quality.

    Directory of Open Access Journals (Sweden)

    Shaoxia Wang

    Full Text Available Although application of Zn combined with macronutrients (K, P, and N can be used to fortify wheat grain with Zn, little is known about their interactions when foliar application is employed or the influences of common soil fertility management practices (e.g. N and straw management on their efficiency. Therefore, the effects of foliar-applied Zn and N, P, or K on grain nutritional quality (especially Zn were investigated in wheat grown under different soil N rates at two sites with (Sanyuan or without (Yangling employing straw return. A 4-year-long field experiment was also conducted to evaluate the environmental stability of the foliar formulations. Across 6 site-years, foliar Zn application alone or combined with N, P, or K fertilizers resulted in 95.7%, 101%, 67.9% and 121% increases in grain Zn concentration, respectively. In terms of increasing grain Zn concentration, foliar-applied Zn positively interacted with N (at Sanyuan and K (at Yangling, but negatively interacted with P at any condition tested, suggesting depressive effects of foliarly-applied P on physiological availability of Zn. Although these interaction effects were the major factor that governing the efficiency of foliar-applied Zn combined with N, P, or K on grain Zn concentration, the magnitude of the increase/decrease in grain Zn (-3.96~5.71 mg kg-1 due to these interactions was much less than the average increases following Zn+K (31.3, Zn+P (18.7, and Zn+N (26.5 mg kg-1 treatments relative to that observed in foliar Zn-only treatment. The combined foliar application of Zn with N, P, or K did not cause any adverse impact on grain yield and other nutritional quality and in some cases slightly increased grain yield and macronutrient concentrations. Grain phytic acid:Zn molar ratios were respectively 52.0%, 53.1%, 43.4% and 63.5% lower in the foliar Zn, Zn+N, Zn+P and Zn+K treatments than in the control treatment. These effects were consistent over four years and across three

  15. Effects of Zn, macronutrients, and their interactions through foliar applications on winter wheat grain nutritional quality.

    Science.gov (United States)

    Wang, Shaoxia; Li, Meng; Liu, Ke; Tian, Xiaohong; Li, Shuo; Chen, Yanlong; Jia, Zhou

    2017-01-01

    Although application of Zn combined with macronutrients (K, P, and N) can be used to fortify wheat grain with Zn, little is known about their interactions when foliar application is employed or the influences of common soil fertility management practices (e.g. N and straw management) on their efficiency. Therefore, the effects of foliar-applied Zn and N, P, or K on grain nutritional quality (especially Zn) were investigated in wheat grown under different soil N rates at two sites with (Sanyuan) or without (Yangling) employing straw return. A 4-year-long field experiment was also conducted to evaluate the environmental stability of the foliar formulations. Across 6 site-years, foliar Zn application alone or combined with N, P, or K fertilizers resulted in 95.7%, 101%, 67.9% and 121% increases in grain Zn concentration, respectively. In terms of increasing grain Zn concentration, foliar-applied Zn positively interacted with N (at Sanyuan) and K (at Yangling), but negatively interacted with P at any condition tested, suggesting depressive effects of foliarly-applied P on physiological availability of Zn. Although these interaction effects were the major factor that governing the efficiency of foliar-applied Zn combined with N, P, or K on grain Zn concentration, the magnitude of the increase/decrease in grain Zn (-3.96~5.71 mg kg-1) due to these interactions was much less than the average increases following Zn+K (31.3), Zn+P (18.7), and Zn+N (26.5 mg kg-1) treatments relative to that observed in foliar Zn-only treatment. The combined foliar application of Zn with N, P, or K did not cause any adverse impact on grain yield and other nutritional quality and in some cases slightly increased grain yield and macronutrient concentrations. Grain phytic acid:Zn molar ratios were respectively 52.0%, 53.1%, 43.4% and 63.5% lower in the foliar Zn, Zn+N, Zn+P and Zn+K treatments than in the control treatment. These effects were consistent over four years and across three soil N

  16. Combining Interactive Thermodynamics Simulations with Screencasts and Conceptests

    Science.gov (United States)

    Falconer, John L.

    2016-01-01

    More than 40 interactive "Mathematica" simulations were prepared for chemical engineering thermodynamics, screencasts were prepared that explain how to use each simulation, and more than 100 ConcepTests were prepared that utilize the simulations. They are located on www.LearnChemE.com. The purposes of these simulations are to clarify…

  17. Human norovirus RNA persists in seawater under simulated winter conditions but does not bioaccumulate efficiently in Pacific Oysters (Crassostrea gigas).

    Science.gov (United States)

    Dancer, D; Rangdale, R E; Lowther, J A; Lees, D N

    2010-11-01

    Norovirus (NoV) is the principal agent of bivalve molluscan shellfish-associated gastroenteric illness worldwide. Currently, noncultivable human NoVs can be detected in bivalve molluscan shellfish by using molecular methods such as real-time reverse transcription PCR assays (qRT-PCR). In addition to infectious viruses, this methodology may also detect noninfectious NoV, including fragments of the NoV genome. This study addresses, in part, the implications of qRT-PCR results for the detection of NoV in shellfish in the absence of an infectivity assay. To evaluate environmental persistence, the stability of a short fragment of the NoV genome, spanning the qRT-PCR target in the open reading frame 1/2 junction, was assessed in seawater under artificial environmental conditions simulating winter in the United Kingdom (1 mW/cm² UV irradiation, 8°C) during a 4-week period. Detectable RNA levels decreased exponentially (T₉₀ of approximately 141 h); however, sequences were still detectable for up to 2 weeks. The ability of Pacific oysters (Crassostrea gigas) to bioaccumulate NoV particles (from human feces) and RNA fragments was also compared using qRT-PCR. Oysters exposed to NoV particles subsequently were positive for NoV by qRT-PCR at levels several orders of magnitude in excess of the theoretical limit of detection, whereas oysters exposed to similar quantities of NoV RNA were either negative or positive at significantly lower levels. Therefore, although noninfectious fragments of NoV RNA may persist in the environment under winter conditions, this type of material will not be efficiently bioaccumulated by Pacific oysters and should not significantly contribute to positive qRT-PCR results.

  18. Origin and pathways of Winter Intermediate Water in the Northwestern Mediterranean Sea using observations and numerical simulation

    Science.gov (United States)

    Juza, Mélanie; Renault, Lionel; Ruiz, Simon; Tintoré, Joaquin

    2013-12-01

    The study of water masses worldwide (their formation, spreading, mixing, and impact on general circulation) is essential for a better understanding of the ocean circulation and variability. In this paper, the formation and main pathways of Winter Intermediate Water (WIW) in the Northwestern Mediterranean Sea (NWMED) are investigated during the winter-spring 2011 using observations and numerical simulation. The main results show that the WIW, formed along the continental shelves of the Gulf of Lion and Balearic Sea, circulates southward following five preferential pathways depending on the WIW formation site location and the oceanic conditions. WIW joins the northeastern part of the Balearic Sea, or flows along the continental shelves until joining the Balearic Current (maximum of 0.33 Sv in early-April) or further south until the Ibiza Channel entrance. Two additional trajectories, contributing to water mass exchanges with the southern part of the Western Mediterranean Sea, bring the WIW through the Ibiza and Mallorca Channels (maxima of 0.26 Sv in late-March and 0.1 Sv in early-April, respectively). The circulation of WIW over the NWMED at 50-200 m depth, its mixing and spreading over the Western Mediterranean Sea (reaching the south of the Balearic Islands, the Algero-Provencal basin, the Ligurian and the Alboran Seas) suggest that the WIW may have an impact on the ocean circulation by eddy blocking effect, exchange of water masses between north and south subbasins of Western Mediterranean Sea through the Ibiza Channel or modification of the ocean stratification.

  19. Simulations of the Boreal Winter Upper Mesosphere and Lower Thermosphere With Meteorological Specifications in SD-WACCM-X

    Science.gov (United States)

    Sassi, Fabrizio; Siskind, David E.; Tate, Jennifer L.; Liu, Han-Li; Randall, Cora E.

    2018-04-01

    We investigate the benefit of high-altitude nudging in simulations of the structure and short-term variability of the upper mesosphere and lower thermosphere (UMLT) dynamical meteorology during boreal winter, specifically around the time of the January 2009 sudden stratospheric warming. We compare simulations using the Specified Dynamics, Whole Atmosphere Community Climate Model, extended version, nudged using atmospheric specifications generated by the Navy Operational Global Atmospheric Prediction System, Advanced Level Physics High Altitude. Two sets of simulations are carried out: one uses nudging over a vertical domain from 0 to 90 km; the other uses nudging over a vertical domain from 0 to 50 km. The dynamical behavior is diagnosed from ensemble mean and standard deviation of winds, temperature, and zonal accelerations due to resolved and parameterized waves. We show that the dynamical behavior of the UMLT is quite different in the two experiments, with prominent differences in the structure and variability of constituent transport. We compare the results of our numerical experiments to observations of carbon monoxide by the Atmospheric Chemistry Experiment-Fourier Transform Spectrometer to show that the high-altitude nudging is capable of reproducing with high fidelity the observed variability, and traveling planetary waves are a crucial component of the dynamics. The results of this study indicate that to capture the key physical processes that affect short-term variability (defined as the atmospheric behavior within about 10 days of a stratospheric warming) in the UMLT, specification of the atmospheric state in the stratosphere alone is not sufficient, and upper atmospheric specifications are needed.

  20. The dissipation and microbial ecotoxicity of tebuconazole and its transformation products in soil under standard laboratory and simulated winter conditions.

    Science.gov (United States)

    El Azhari, Najoi; Dermou, Eftychia; Barnard, Romain L; Storck, Veronika; Tourna, Maria; Beguet, Jérémie; Karas, Panagiotis A; Lucini, Luigi; Rouard, Nadine; Botteri, Lucio; Ferrari, Federico; Trevisan, Marco; Karpouzas, Dimitrios G; Martin-Laurent, Fabrice

    2018-05-12

    Tebuconazole (TBZ) is a widely used triazole fungicide at EU level on cereals and vines. It is relatively persistent in soil where it is transformed to various transformation products (TPs) which might be environmentally relevant. We assessed the dissipation of TBZ in soil under contrasting incubation conditions (standard vs winter simulated) that are relevant to its application scheme, determined its transformation pathway using advanced analytical tools and 14 C-labeled TBZ and assessed its soil microbial toxicity. Mineralization of 14 C-triazole-ring-labeled TBZ was negligible but up to 11% of 14 C-penyl-ring-labeled TBZ evolved as 14 CO 2 within 150 days of incubation. TBZ persistence increased at higher dose rates (×10 compared to the recommended agronomical dose ×1) and under winter simulated conditions compared to standard incubation conditions (at ×1 dose rate DT 50 of 202 and 88 days, respectively). Non-target suspect screening enabled the detection of 22 TPs of TBZ, among which 17 were unknown. Mass spectrometry analysis led to the identification of 1-(4-chlorophenyl) ethanone, a novel TP of TBZ, the formation of which and decay in soil was determined by gas chromatography mass spectrometry. Three hypothetical transformation pathways of TBZ, all converging to 1H-1,2,4-triazole are proposed based on suspect screening. The ecotoxicological effect of TBZ and of its TPs was assessed by measuring by qPCR the abundance of the total bacteria and the relative abundance of 11 prokaryotic taxa and 4 functional groups. A transient impact of TBZ on the relative abundance of all prokaryotic taxa (except α-proteobacteria and Bacteroidetes) and one functional microbial group (pcaH-carrying microorganisms) was observed. However the direction of the effect (positive or negative) varied, and in certain cases, depended on the incubation conditions. Proteobacteria was the most responsive phylum to TBZ with recovery observed 20 days after treatment. The

  1. Four dimensional data assimilation (FDDA) impacts on WRF performance in simulating inversion layer structure and distributions of CMAQ-simulated winter ozone concentrations in Uintah Basin

    Science.gov (United States)

    Tran, Trang; Tran, Huy; Mansfield, Marc; Lyman, Seth; Crosman, Erik

    2018-03-01

    Four-dimensional data assimilation (FDDA) was applied in WRF-CMAQ model sensitivity tests to study the impact of observational and analysis nudging on model performance in simulating inversion layers and O3 concentration distributions within the Uintah Basin, Utah, U.S.A. in winter 2013. Observational nudging substantially improved WRF model performance in simulating surface wind fields, correcting a 10 °C warm surface temperature bias, correcting overestimation of the planetary boundary layer height (PBLH) and correcting underestimation of inversion strengths produced by regular WRF model physics without nudging. However, the combined effects of poor performance of WRF meteorological model physical parameterization schemes in simulating low clouds, and warm and moist biases in the temperature and moisture initialization and subsequent simulation fields, likely amplified the overestimation of warm clouds during inversion days when observational nudging was applied, impacting the resulting O3 photochemical formation in the chemistry model. To reduce the impact of a moist bias in the simulations on warm cloud formation, nudging with the analysis water mixing ratio above the planetary boundary layer (PBL) was applied. However, due to poor analysis vertical temperature profiles, applying analysis nudging also increased the errors in the modeled inversion layer vertical structure compared to observational nudging. Combining both observational and analysis nudging methods resulted in unrealistically extreme stratified stability that trapped pollutants at the lowest elevations at the center of the Uintah Basin and yielded the worst WRF performance in simulating inversion layer structure among the four sensitivity tests. The results of this study illustrate the importance of carefully considering the representativeness and quality of the observational and model analysis data sets when applying nudging techniques within stable PBLs, and the need to evaluate model results

  2. Simulation of the Impacts of Urbanization on Winter Meteorological Fields over the Pearl River Delta Region

    Directory of Open Access Journals (Sweden)

    Naixing Luo

    2017-01-01

    Full Text Available The influences of urbanization on weather in Guangdong Province, China, were studied using the Weather Research and Forecasting model from 31 December 2009 through 3 January 2010. Model outputs were compared with extensive monitoring of meteorological data to examine the simulation ability. Model results between tests (with and without land-use change show that the urbanization had major effects on meteorological fields across nearly the entire Pearl River Delta region and particularly in urban areas. Studied fields (wind speed, temperature, precipitation, and sensible and latent heat fluxes were affected by the urbanization of the PRD region. The major influences occurred in urban areas, where wind speeds decreased greatly, while the daytime surface upward sensible heat flux clearly increased. Unlike the sensible heat flux, the latent heat flux had a nonmonotonic increase or decrease. As a consequence of the two heat fluxes, 2-m temperature varied with location and time. Change of precipitation was complex. The main rain band became more concentrated, while precipitation decreased upwind of the urban area and increased downwind.

  3. Coupled climate model simulations of Mediterranean winter cyclones and large-scale flow patterns

    Directory of Open Access Journals (Sweden)

    B. Ziv

    2013-03-01

    Full Text Available The study aims to evaluate the ability of global, coupled climate models to reproduce the synoptic regime of the Mediterranean Basin. The output of simulations of the 9 models included in the IPCC CMIP3 effort is compared to the NCEP-NCAR reanalyzed data for the period 1961–1990. The study examined the spatial distribution of cyclone occurrence, the mean Mediterranean upper- and lower-level troughs, the inter-annual variation and trend in the occurrence of the Mediterranean cyclones, and the main large-scale circulation patterns, represented by rotated EOFs of 500 hPa and sea level pressure. The models reproduce successfully the two maxima in cyclone density in the Mediterranean and their locations, the location of the average upper- and lower-level troughs, the relative inter-annual variation in cyclone occurrences and the structure of the four leading large scale EOFs. The main discrepancy is the models' underestimation of the cyclone density in the Mediterranean, especially in its western part. The models' skill in reproducing the cyclone distribution is found correlated with their spatial resolution, especially in the vertical. The current improvement in model spatial resolution suggests that their ability to reproduce the Mediterranean cyclones would be improved as well.

  4. Impacts of interactive dust and its direct radiative forcing on interannual variations of temperature and precipitation in winter over East Asia: Impacts of Dust on IAVs of Temperature

    Energy Technology Data Exchange (ETDEWEB)

    Lou, Sijia [Scripps Institution of Oceanography, University of California, San Diego, La Jolla California USA; Atmospheric Science and Global Change Division, Pacific Northwest National Laboratory, Richland Washington USA; Russell, Lynn M. [Scripps Institution of Oceanography, University of California, San Diego, La Jolla California USA; Yang, Yang [Scripps Institution of Oceanography, University of California, San Diego, La Jolla California USA; Atmospheric Science and Global Change Division, Pacific Northwest National Laboratory, Richland Washington USA; Liu, Ying [Atmospheric Science and Global Change Division, Pacific Northwest National Laboratory, Richland Washington USA; Singh, Balwinder [Atmospheric Science and Global Change Division, Pacific Northwest National Laboratory, Richland Washington USA; Ghan, Steven J. [Atmospheric Science and Global Change Division, Pacific Northwest National Laboratory, Richland Washington USA

    2017-08-24

    We used 150-year pre-industrial simulations of the Community Earth System Model (CESM) to quantify the impacts of interactively-modeled dust emissions on the interannual variations of temperature and precipitation over East Asia during the East Asian Winter Monsoon (EAWM) season. The simulated December-January-February dust column burden and dust optical depth are lower over northern China in the strongest EAWM years than those of the weakest years, with regional mean values lower by 38.3% and 37.2%, respectively. The decrease in dust over the dust source regions (the Taklamakan and Gobi Deserts) and the downwind region (such as the North China Plain) leads to an increase in direct radiative forcing (RF) both at the surface and top of atmosphere by up to 1.5 and 0.75 W m-2, respectively. The effects of EAWM-related variations in surface winds, precipitation and their effects on dust emissions and wet removal contribute about 67% to the total dust-induced variations of direct RF at the surface and partly offset the cooling that occurs with the EAWM strengthening by heating the surface. The variations of surface air temperature induced by the changes in wind and dust emissions increase by 0.4-0.6 K over eastern coastal China, northeastern China, and Japan, which weakens the impact of EAWM on surface air temperature by 3–18% in these regions. The warming results from the combined effects of changes in direct RF and easterly wind anomalies that bring warm air from the ocean to these regions. Moreover, the feedback of the changes in wind on dust emissions weakens the variations of the sea level pressure gradient on the Siberian High while enhancing the Maritime Continent Low. Therefore, cold air is prevented from being transported from Siberia, Kazakhstan, western and central China to the western Pacific Ocean and decreases surface air temperature by 0.6 K and 2 K over central China and the Tibetan Plateau, respectively. Over eastern coastal China, the variations of

  5. Organisational learning via Interactive Process Simulation in AGE

    NARCIS (Netherlands)

    Szirbik, N. B.; Roest, G. B.; Sklenar, J; Tanguy, A; Bertelle, C; Fortino, G

    2007-01-01

    In this paper, the concept of Interactive Process Simulation is introduced as a specialisation of Business Gaming. A specific gaming and agent development framework, based oil interactive simulation and a specific modelling langauge, is shortly presented. The concepts of the language are explained

  6. Web-based Interactive Simulator for Rotating Machinery.

    Science.gov (United States)

    Sirohi, Vijayalaxmi

    1999-01-01

    Baroma (Balance of Rotating Machinery), the Web-based educational engineering interactive software for teaching/learning combines didactical and software ergonomical approaches. The software in tutorial form simulates a problem using Visual Interactive Simulation in graphic display, and animation is brought about through graphical user interface…

  7. Simulated galaxy interactions as probes of merger spectral energy distributions

    Energy Technology Data Exchange (ETDEWEB)

    Lanz, Lauranne; Zezas, Andreas; Smith, Howard A.; Ashby, Matthew L. N.; Fazio, Giovanni G.; Hernquist, Lars [Harvard-Smithsonian Center for Astrophysics, 60 Garden St., Cambridge, MA 02138 (United States); Hayward, Christopher C. [Heidelberger Institut für Theoretische Studien, Schloss-Wolfsbrunnenweg 35, D-69118 Heidelberg (Germany); Brassington, Nicola, E-mail: llanz@ipac.caltech.edu [School of Physics, Astronomy and Mathematics, University of Hertfordshire, College Lane, Hatfield, AL10 9AB (United Kingdom)

    2014-04-10

    We present the first systematic comparison of ultraviolet-millimeter spectral energy distributions (SEDs) of observed and simulated interacting galaxies. Our sample is drawn from the Spitzer Interacting Galaxy Survey and probes a range of galaxy interaction parameters. We use 31 galaxies in 14 systems which have been observed with Herschel, Spitzer, GALEX, and 2MASS. We create a suite of GADGET-3 hydrodynamic simulations of isolated and interacting galaxies with stellar masses comparable to those in our sample of interacting galaxies. Photometry for the simulated systems is then calculated with the SUNRISE radiative transfer code for comparison with the observed systems. For most of the observed systems, one or more of the simulated SEDs match reasonably well. The best matches recover the infrared luminosity and the star formation rate of the observed systems, and the more massive systems preferentially match SEDs from simulations of more massive galaxies. The most morphologically distorted systems in our sample are best matched to the simulated SEDs that are close to coalescence, while less evolved systems match well with the SEDs over a wide range of interaction stages, suggesting that an SED alone is insufficient for identifying the interaction stage except during the most active phases in strongly interacting systems. This result is supported by our finding that the SEDs calculated for simulated systems vary little over the interaction sequence.

  8. Validation of Multibody Program to Optimize Simulated Trajectories II Parachute Simulation with Interacting Forces

    Science.gov (United States)

    Raiszadeh, Behzad; Queen, Eric M.; Hotchko, Nathaniel J.

    2009-01-01

    A capability to simulate trajectories of multiple interacting rigid bodies has been developed, tested and validated. This capability uses the Program to Optimize Simulated Trajectories II (POST 2). The standard version of POST 2 allows trajectory simulation of multiple bodies without force interaction. In the current implementation, the force interaction between the parachute and the suspended bodies has been modeled using flexible lines, allowing accurate trajectory simulation of the individual bodies in flight. The POST 2 multibody capability is intended to be general purpose and applicable to any parachute entry trajectory simulation. This research paper explains the motivation for multibody parachute simulation, discusses implementation methods, and presents validation of this capability.

  9. Evaluation of the Community Multiscale Air Quality Model for Simulating Winter Ozone Formation in the Uinta Basin

    Science.gov (United States)

    Matichuk, Rebecca; Tonnesen, Gail; Luecken, Deborah; Gilliam, Rob; Napelenok, Sergey L.; Baker, Kirk R.; Schwede, Donna; Murphy, Ben; Helmig, Detlev; Lyman, Seth N.; Roselle, Shawn

    2017-12-01

    The Weather Research and Forecasting (WRF) and Community Multiscale Air Quality (CMAQ) models were used to simulate a 10 day high-ozone episode observed during the 2013 Uinta Basin Winter Ozone Study (UBWOS). The baseline model had a large negative bias when compared to ozone (O3) and volatile organic compound (VOC) measurements across the basin. Contrary to other wintertime Uinta Basin studies, predicted nitrogen oxides (NOx) were typically low compared to measurements. Increases to oil and gas VOC emissions resulted in O3 predictions closer to observations, and nighttime O3 improved when reducing the deposition velocity for all chemical species. Vertical structures of these pollutants were similar to observations on multiple days. However, the predicted surface layer VOC mixing ratios were generally found to be underestimated during the day and overestimated at night. While temperature profiles compared well to observations, WRF was found to have a warm temperature bias and too low nighttime mixing heights. Analyses of more realistic snow heat capacity in WRF to account for the warm bias and vertical mixing resulted in improved temperature profiles, although the improved temperature profiles seldom resulted in improved O3 profiles. While additional work is needed to investigate meteorological impacts, results suggest that the uncertainty in the oil and gas emissions contributes more to the underestimation of O3. Further, model adjustments based on a single site may not be suitable across all sites within the basin.

  10. Simulating the formation of carbonaceous aerosol in a European Megacity (Paris during the MEGAPOLI summer and winter campaigns

    Directory of Open Access Journals (Sweden)

    C. Fountoukis

    2016-03-01

    Full Text Available We use a three-dimensional regional chemical transport model (PMCAMx with high grid resolution and high-resolution emissions (4 × 4 km2 over the Paris greater area to simulate the formation of carbonaceous aerosol during a summer (July 2009 and a winter (January/February 2010 period as part of the MEGAPOLI (megacities: emissions, urban, regional, and global atmospheric pollution and climate effects, and Integrated tools for assessment and mitigation campaigns. Model predictions of carbonaceous aerosol are compared against Aerodyne aerosol mass spectrometer and black carbon (BC high time resolution measurements from three ground sites. PMCAMx predicts BC concentrations reasonably well reproducing the majority (70 % of the hourly data within a factor of two during both periods. The agreement for the summertime secondary organic aerosol (OA concentrations is also encouraging (mean bias = 0.1 µg m−3 during a photochemically intense period. The model tends to underpredict the summertime primary OA concentrations in the Paris greater area (by approximately 0.8 µg m−3 mainly due to missing primary OA emissions from cooking activities. The total cooking emissions are estimated to be approximately 80 mg d−1 per capita and have a distinct diurnal profile in which 50 % of the daily cooking OA is emitted during lunch time (12:00–14:00 LT and 20 % during dinner time (20:00–22:00 LT. Results also show a large underestimation of secondary OA in the Paris greater area during wintertime (mean bias =  −2.3 µg m−3 pointing towards a secondary OA formation process during low photochemical activity periods that is not simulated in the model.

  11. Simulating the formation of carbonaceous aerosol in a European Megacity (Paris) during the MEGAPOLI summer and winter campaigns

    Science.gov (United States)

    Fountoukis, Christos; Megaritis, Athanasios G.; Skyllakou, Ksakousti; Charalampidis, Panagiotis E.; Denier van der Gon, Hugo A. C.; Crippa, Monica; Prévôt, André S. H.; Fachinger, Friederike; Wiedensohler, Alfred; Pilinis, Christodoulos; Pandis, Spyros N.

    2016-03-01

    We use a three-dimensional regional chemical transport model (PMCAMx) with high grid resolution and high-resolution emissions (4 × 4 km2) over the Paris greater area to simulate the formation of carbonaceous aerosol during a summer (July 2009) and a winter (January/February 2010) period as part of the MEGAPOLI (megacities: emissions, urban, regional, and global atmospheric pollution and climate effects, and Integrated tools for assessment and mitigation) campaigns. Model predictions of carbonaceous aerosol are compared against Aerodyne aerosol mass spectrometer and black carbon (BC) high time resolution measurements from three ground sites. PMCAMx predicts BC concentrations reasonably well reproducing the majority (70 %) of the hourly data within a factor of two during both periods. The agreement for the summertime secondary organic aerosol (OA) concentrations is also encouraging (mean bias = 0.1 µg m-3) during a photochemically intense period. The model tends to underpredict the summertime primary OA concentrations in the Paris greater area (by approximately 0.8 µg m-3) mainly due to missing primary OA emissions from cooking activities. The total cooking emissions are estimated to be approximately 80 mg d-1 per capita and have a distinct diurnal profile in which 50 % of the daily cooking OA is emitted during lunch time (12:00-14:00 LT) and 20 % during dinner time (20:00-22:00 LT). Results also show a large underestimation of secondary OA in the Paris greater area during wintertime (mean bias = -2.3 µg m-3) pointing towards a secondary OA formation process during low photochemical activity periods that is not simulated in the model.

  12. Simulation of coherent interactions between Rydberg atoms

    International Nuclear Information System (INIS)

    Robicheaux, F.; Hernandez, J.V.; Topcu, T.; Noordam, L.D.

    2004-01-01

    The results of a theoretical investigation of the coherent interaction between many Rydberg atoms are reported. The atoms are assumed to move very little during the time range we investigate. We describe the basic interaction between atoms and show that (contrary to previous theoretical studies) the interaction between the atoms can be coherent. The band structure for a perfect lattice of atoms and the density of states for an amorphous distribution of atoms are presented. We also give results for when the atoms are roughly positioned in a lattice. Finally, we performed detailed calculations to understand when the Rydberg interactions are too strong for an essential states type of approximation. The relevance of our results to previous measurements in a Rydberg gas and to possible future experiments is discussed

  13. IMPETUS - Interactive MultiPhysics Environment for Unified Simulations.

    Science.gov (United States)

    Ha, Vi Q; Lykotrafitis, George

    2016-12-08

    We introduce IMPETUS - Interactive MultiPhysics Environment for Unified Simulations, an object oriented, easy-to-use, high performance, C++ program for three-dimensional simulations of complex physical systems that can benefit a large variety of research areas, especially in cell mechanics. The program implements cross-communication between locally interacting particles and continuum models residing in the same physical space while a network facilitates long-range particle interactions. Message Passing Interface is used for inter-processor communication for all simulations. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. Mediterranean Thermohaline Response to Large-Scale Winter Atmospheric Forcing in a High-Resolution Ocean Model Simulation

    Science.gov (United States)

    Cusinato, Eleonora; Zanchettin, Davide; Sannino, Gianmaria; Rubino, Angelo

    2018-04-01

    Large-scale circulation anomalies over the North Atlantic and Euro-Mediterranean regions described by dominant climate modes, such as the North Atlantic Oscillation (NAO), the East Atlantic pattern (EA), the East Atlantic/Western Russian (EAWR) and the Mediterranean Oscillation Index (MOI), significantly affect interannual-to-decadal climatic and hydroclimatic variability in the Euro-Mediterranean region. However, whereas previous studies assessed the impact of such climate modes on air-sea heat and freshwater fluxes in the Mediterranean Sea, the propagation of these atmospheric forcing signals from the surface toward the interior and the abyss of the Mediterranean Sea remains unexplored. Here, we use a high-resolution ocean model simulation covering the 1979-2013 period to investigate spatial patterns and time scales of the Mediterranean thermohaline response to winter forcing from NAO, EA, EAWR and MOI. We find that these modes significantly imprint on the thermohaline properties in key areas of the Mediterranean Sea through a variety of mechanisms. Typically, density anomalies induced by all modes remain confined in the upper 600 m depth and remain significant for up to 18-24 months. One of the clearest propagation signals refers to the EA in the Adriatic and northern Ionian seas: There, negative EA anomalies are associated to an extensive positive density response, with anomalies that sink to the bottom of the South Adriatic Pit within a 2-year time. Other strong responses are the thermally driven responses to the EA in the Gulf of Lions and to the EAWR in the Aegean Sea. MOI and EAWR forcing of thermohaline properties in the Eastern Mediterranean sub-basins seems to be determined by reinforcement processes linked to the persistency of these modes in multiannual anomalous states. Our study also suggests that NAO, EA, EAWR and MOI could critically interfere with internal, deep and abyssal ocean dynamics and variability in the Mediterranean Sea.

  15. The Electron Transport Chain: An Interactive Simulation

    Science.gov (United States)

    Romero, Chris; Choun, James

    2014-01-01

    This activity provides students an interactive demonstration of the electron transport chain and chemiosmosis during aerobic respiration. Students use simple, everyday objects as hydrogen ions and electrons and play the roles of the various proteins embedded in the inner mitochondrial membrane to show how this specific process in cellular…

  16. Euclidean Monte Carlo simulation of nuclear interactions

    International Nuclear Information System (INIS)

    Montvay, Istvan; Bonn Univ.; Urbach, Carsten

    2011-05-01

    We present an exploratory study of chiral effective theories of nuclei with methods adopted from lattice quantum chromodynamics (QCD). We show that the simulations in the Euclidean path integral approach are feasible and that we can determine the energy of the two nucleon state. By varying the parameters and the simulated volumes phase shifts can be determined in principle and hopefully tuned to their physical values in the future. The physical cut-off of the theory is realised by blocking of the lattice fields. By keeping this physical cut-off fixed in physical units the lattice cut-off can be changed and in this way the lattice artefacts can be eliminated. (orig.)

  17. Simulation study of the beam-beam interaction at SPEAR

    International Nuclear Information System (INIS)

    Tennyson, J.

    1980-01-01

    A two dimensional simulation study of the beam-beam interaction at SPEAR indicates that quantum fluctuations affecting the horizontal betatron oscillation play a critical role in the vertical beam blowup

  18. Response of winter North Atlantic storm track to climate change in the CNRM-CM5 simulations

    Science.gov (United States)

    Chauvin, Fabrice; Oudar, Thomas; Sanchez-Gomez, Emilia; Terray, Laurent

    2016-04-01

    Climate variability in Europe in winter is largely controlled by North Atlantic storm tracks. These are associated with transport of energy, momentum, and water vapour, between the equator and mid latitudes. Extratropical cyclones have caused severe damages over some regions in north-western Europe, since they can combine extreme precipitation and strong winds. This is why it is relevant to study the impact of climate change on the extratropical cyclones, principally on their intensity, position or lifespan. Indeed, several recent studies have focused on this subject by using atmospheric reanalysis and general circulation models (GCMs). The main conclusions from the CMIP3 simulations showed a decreasing of the total number of cyclones and a poleward shift of their tracks in response to global warming. In the recent CMIP5 exercise, the consensus is not so clear, probably due to more complex feedbacks acting in the different models. Thus, the question of changes in North Atlantic storm-tracks with warming remains open. The main goal of this work is to explore the changes in the North Atlantic storm-tracks in the past and future decades and to analyze the contributions of the different external forcings (natural and anthropogenic) versus the internal variability. On this purpose, we use the Detection and Attribution (D&A) simulations performed with the coupled model CNRM-CM5. To characterize the extratropical cyclones and their tracks, a tracking scheme based on the detection of maximum of relative vorticity at 850 hPa is conducted. We show that the coupled model fairly well reproduces the storm genesis locations as well as the tracks pathways comparing to several atmospheric reanalysis products. In the recent historical period (1950-2005), the model shows a decrease in the number of storms in the southern North-Atlantic, when all the forcings (anthropogenic and natural) are prescribed. Even if the role of internal variability is important in the last decades (the

  19. Interactive Modelling and Simulation of Human Motion

    DEFF Research Database (Denmark)

    Engell-Nørregård, Morten Pol

    menneskers led, der udviser både ikke-konveksitet og flere frihedsgrader • En generel og alsidig model for aktivering af bløde legemer. Modellen kan anvendes som et animations værktøj, men er lige så velegnet til simulering af menneskelige muskler, da den opfylder de grundlæggende fysiske principper......Dansk resumé Denne ph.d.-afhandling beskæftiger sig med modellering og simulation af menneskelig bevægelse. Emnerne i denne afhandling har mindst to ting til fælles. For det første beskæftiger de sig med menneskelig bevægelse. Selv om de udviklede modeller også kan benyttes til andre ting,er det...... primære fokus på at modellere den menneskelige krop. For det andet, beskæftiger de sig alle med simulering som et redskab til at syntetisere bevægelse og dermed skabe animationer. Dette er en vigtigt pointe, da det betyder, at vi ikke kun skaber værktøjer til animatorer, som de kan bruge til at lave sjove...

  20. Simulation of interactions at the LHC

    Energy Technology Data Exchange (ETDEWEB)

    Duckeck, Guenter [Munich Univ. (Germany). Physics Faculty

    2016-11-01

    The LHC Run-2 is planned to continue until end of 2018 and should increase the data volume by at least a factor 5 compared to Run-1. A corresponding increase of the simulated data volume is required in order to analyze and interpret the recorded data. This will allow us to determine with much better precision the properties of the Higgs Boson and either find new particles as predicted by 'New Physics' theories or further increase the constraints on these models. Using SuperMUC to simulate events will be a crucial component to reach these goals. Active development of the simulation software is ongoing in order to make the workflow more flexible and better parallelizable for smaller work-units. Adapting the software for Intel/Mic architectures is an important goal, though presumably more in the long-term after LHC Run-2 (Run-3 is planned to start in 2021). We would hope that ''SuperMUC Next Generation'' provides Intel/Mic architecture extensions.

  1. An Interactive Simulation Tool for Production Planning in Bacon Factories

    DEFF Research Database (Denmark)

    Nielsen, Jens Frederik Dalsgaard; Nielsen, Kirsten Mølgaard

    1994-01-01

    The paper describes an interactive simulation tool for production planning in bacon factories. The main aim of the tool is to make it possible to combine the production plans of all parts of the factory......The paper describes an interactive simulation tool for production planning in bacon factories. The main aim of the tool is to make it possible to combine the production plans of all parts of the factory...

  2. Simulation of AntiMatter–Matter Interactions in Geant4

    Directory of Open Access Journals (Sweden)

    Galoyan Aida

    2018-01-01

    Full Text Available Cross sections of antiproton and antinucleus interactions with nuclei are calculated using stochastic averaging method. A new implementation of the Quark-Gluon-String Model (QGSM is proposed for simulation of multi-particle production in antinucleus-nucleus collisions. A combination of the cross sections and the new implementation of QGSM allows experimental data on antiproton and antinucleus interactions with nuclei to be described. The combination is included in the well-known Geant4 simulation toolkit.

  3. INTERACTIVE MOTION PLATFORMS AND VIRTUAL REALITY FOR VEHICLE SIMULATORS

    Directory of Open Access Journals (Sweden)

    Evžen Thöndel

    2017-12-01

    Full Text Available Interactive motion platforms are intended for vehicle simulators, where the direct interaction of the human body is used for controlling the simulated vehicle (e.g. bicycle, motorbike or other sports vehicles. The second use of interactive motion platforms is for entertainment purposes or fitness. The development of interactive motion platforms reacts to recent calls in the simulation industry to provide a device, which further enhances the virtual reality experience, especially with connection to the new and very fast growing business in virtual reality glasses. The paper looks at the design and control of an interactive motion platform with two degrees of freedom to be used in virtual reality applications. The paper provides the description of the control methods and new problems related to the virtual reality sickness are discussed here.

  4. Interactive Simulations to Support Quantum Mechanics Instruction for Chemistry Students

    Science.gov (United States)

    Kohnle, Antje; Benfield, Cory; Hahner, Georg; Paetkau, Mark

    2017-01-01

    The QuVis Quantum Mechanics Visualization Project provides freely available research-based interactive simulations with accompanying activities for the teaching and learning of quantum mechanics across a wide range of topics and levels. This article gives an overview of some of the simulations and describes their use in an introductory physical…

  5. Mesoscale simulations of hydrodynamic squirmer interactions.

    Science.gov (United States)

    Götze, Ingo O; Gompper, Gerhard

    2010-10-01

    The swimming behavior of self-propelled microorganisms is studied by particle-based mesoscale simulations. The simulation technique includes both hydrodynamics and thermal fluctuations that are both essential for the dynamics of microswimmers. The swimmers are modeled as squirmers, i.e., spherical objects with a prescribed tangential surface velocity, where the focus of thrust generation can be tuned from pushers to pullers. For passive squirmers (colloids), we show that the velocity autocorrelation function agrees quantitatively with the Boussinesq approximation. Single active squirmers show a persistent random-walk behavior, determined by forward motion, lateral diffusion, and orientational fluctuations, in agreement with theoretical predictions. For pairs of squirmers, which are initially swimming in parallel, we find an attraction for pushers and a repulsion for pullers, as expected. The hydrodynamic force between squirmer pairs is calculated as a function of the center-to-center distances d(cm) and is found to be consistent with a logarithmic distance dependence for d(cm) less than about two sphere diameters; here, the force is considerably stronger than expected from the far-field expansion. The dependence of the force strength on the asymmetry of the polar surface velocity is obtained. During the collision process, thermal fluctuations turn out to be very important and to strongly affect the postcollision velocity directions of both squirmers.

  6. Simulation of cosmic ray interaction at Saturne

    International Nuclear Information System (INIS)

    Michel, R.

    1996-01-01

    Accelerator experiments provide the basis for the development of physical models describing the production of cosmogenic nuclides by cosmic ray particles. Here, experiments are presented by which the irradiation of stony and iron meteoroids in space by galactic cosmic ray protons was successfully simulated; two thick spherical targets made of gabbro and of steel with radii of 25 and 10 cm, respectively, were isotropically irradiated with 1.6 GeV protons at LNS. The artificial meteoroids contained large numbers of individual small targets of up to 27 elements in which the depth-dependent production of radioactive and stable nuclides was analyzed by model calculations based on depth-dependent spectra of primary and secondary particles calculated by the HERMES code system and on experimental and theoretical thin-target cross sections. Due to the results of the two simulation experiments at LNS a consistent modelling of cosmogenic nuclide production rates in stony and iron meteorites was achieved for the first time which allows to interpret the observed abundances of cosmogenic nuclides in stony and iron meteorites with respect to their exposure histories and to describe the history of the cosmic radiation itself. (author)

  7. Stand, Harvest, and Equipment Interactions in Simulated Harvesting Prescriptions

    Science.gov (United States)

    Jingxin Wang; W. Dale Greene; Bryce J. Stokes

    1998-01-01

    We evaluated potential interactions of stand type, harvesting method, and equipment in an experiment using interactive simulation. We examined three felling methods (chain saw, feller-buncher, harvester) and two extraction methods (grapple skidder and forwarder) performing clearcuts, sheltenvood cuts, and single-tree selection cuts in both an uneven-aged natural stand...

  8. Winter is losing its cool

    Science.gov (United States)

    Feng, S.

    2017-12-01

    Winter seasons have significant societal impacts across all sectors ranging from direct human health to ecosystems, transportation, and recreation. This study quantifies the severity of winter and its spatial-temporal variations using a newly developed winter severity index and daily temperature, snowfall and snow depth. The winter severity and the number of extreme winter days are decreasing across the global terrestrial areas during 1901-2015 except the southeast United States and isolated regions in the Southern Hemisphere. These changes are dominated by winter warming, while the changes in daily snowfall and snow depth played a secondary role. The simulations of multiple CMIP5 climate models can well capture the spatial and temporal variations of the observed changes in winter severity and extremes during 1951-2005. The models are consistent in projecting a future milder winter under various scenarios. The winter severity is projected to decrease 60-80% in the middle-latitude Northern Hemisphere under the business-as-usual scenario. The winter arrives later, ends earlier and the length of winter season will be notably shorter. The changes in harsh winter in the polar regions are weak, mainly because the warming leads to more snowfall in the high latitudes.

  9. The engineering approach to winter sports

    CERN Document Server

    Cheli, Federico; Maldifassi, Stefano; Melzi, Stefano; Sabbioni, Edoardo

    2016-01-01

    The Engineering Approach to Winter Sports presents the state-of-the-art research in the field of winter sports in a harmonized and comprehensive way for a diverse audience of engineers, equipment and facilities designers, and materials scientists. The book examines the physics and chemistry of snow and ice with particular focus on the interaction (friction) between sports equipment and snow/ice, how it is influenced by environmental factors, such as temperature and pressure, as well as by contaminants and how it can be modified through the use of ski waxes or the microtextures of blades or ski soles. The authors also cover, in turn, the different disciplines in winter sports:  skiing (both alpine and cross country), skating and jumping, bob sledding and skeleton, hockey and curling, with attention given to both equipment design and on the simulation of gesture and  track optimization.

  10. Mathematical simulation of point defect interaction with grain boundaries

    International Nuclear Information System (INIS)

    Bojko, V.S.

    1987-01-01

    Published works, where the interaction of point defects and grain boundaries was studied by mathematical simulation methods, have been analysed. Energetics of the vacancy formation both in nuclei of large-angle special grain boundaries and in lattice regions adjoining them has been considered. The data obtained permit to explain specific features of grain-boundary diffusion processes. Results of mathematical simulation of the interaction of impurity atoms and boundaries have been considered. Specific features of the helium atom interaction with large-angle grain boundaries are analysed as well

  11. EVALUATING AUSTRALIAN FOOTBALL LEAGUE PLAYER CONTRIBUTIONS USING INTERACTIVE NETWORK SIMULATION

    Directory of Open Access Journals (Sweden)

    Jonathan Sargent

    2013-03-01

    Full Text Available This paper focuses on the contribution of Australian Football League (AFL players to their team's on-field network by simulating player interactions within a chosen team list and estimating the net effect on final score margin. A Visual Basic computer program was written, firstly, to isolate the effective interactions between players from a particular team in all 2011 season matches and, secondly, to generate a symmetric interaction matrix for each match. Negative binomial distributions were fitted to each player pairing in the Geelong Football Club for the 2011 season, enabling an interactive match simulation model given the 22 chosen players. Dynamic player ratings were calculated from the simulated network using eigenvector centrality, a method that recognises and rewards interactions with more prominent players in the team network. The centrality ratings were recorded after every network simulation and then applied in final score margin predictions so that each player's match contribution-and, hence, an optimal team-could be estimated. The paper ultimately demonstrates that the presence of highly rated players, such as Geelong's Jimmy Bartel, provides the most utility within a simulated team network. It is anticipated that these findings will facilitate optimal AFL team selection and player substitutions, which are key areas of interest to coaches. Network simulations are also attractive for use within betting markets, specifically to provide information on the likelihood of a chosen AFL team list "covering the line".

  12. Simulating human behavior for national security human interactions.

    Energy Technology Data Exchange (ETDEWEB)

    Bernard, Michael Lewis; Hart, Dereck H.; Verzi, Stephen J.; Glickman, Matthew R.; Wolfenbarger, Paul R.; Xavier, Patrick Gordon

    2007-01-01

    This 3-year research and development effort focused on what we believe is a significant technical gap in existing modeling and simulation capabilities: the representation of plausible human cognition and behaviors within a dynamic, simulated environment. Specifically, the intent of the ''Simulating Human Behavior for National Security Human Interactions'' project was to demonstrate initial simulated human modeling capability that realistically represents intra- and inter-group interaction behaviors between simulated humans and human-controlled avatars as they respond to their environment. Significant process was made towards simulating human behaviors through the development of a framework that produces realistic characteristics and movement. The simulated humans were created from models designed to be psychologically plausible by being based on robust psychological research and theory. Progress was also made towards enhancing Sandia National Laboratories existing cognitive models to support culturally plausible behaviors that are important in representing group interactions. These models were implemented in the modular, interoperable, and commercially supported Umbra{reg_sign} simulation framework.

  13. i3Drive, a 3D interactive driving simulator.

    Science.gov (United States)

    Ambroz, Miha; Prebil, Ivan

    2010-01-01

    i3Drive, a wheeled-vehicle simulator, can accurately simulate vehicles of various configurations with up to eight wheels in real time on a desktop PC. It presents the vehicle dynamics as an interactive animation in a virtual 3D environment. The application is fully GUI-controlled, giving users an easy overview of the simulation parameters and letting them adjust those parameters interactively. It models all relevant vehicle systems, including the mechanical models of the suspension, power train, and braking and steering systems. The simulation results generally correspond well with actual measurements, making the system useful for studying vehicle performance in various driving scenarios. i3Drive is thus a worthy complement to other, more complex tools for vehicle-dynamics simulation and analysis.

  14. Interactive Anatomy-Augmented Virtual Simulation Training.

    Science.gov (United States)

    Aebersold, Michelle; Voepel-Lewis, Terri; Cherara, Leila; Weber, Monica; Khouri, Christina; Levine, Robert; Tait, Alan R

    2018-02-01

    Traditionally, clinical psychomotor skills are taught through videos and demonstration by faculty which does not allow for the visualization of internal structures and anatomical landmarks that would enhance the learner skill performance. Sophomore and junior nursing students attending a large Midwestern Institution (N=69) participated in this mixed methods study. Students demonstrated their ability to place a nasogastric tube (NGT) after being randomly assigned to usual training (Control group) or an iPad anatomy-augmented virtual simulation training module (AR group). The ability of the participants to demonstrate competence in placing the NGT was assessed using a 17-item competency checklist. After the demonstration, students completed a survey to elicit information about students' level of training, prior experience with NGT placement, satisfaction with the AR technology, and perceptions of AR as a potential teaching tool for clinical skills training. The ability to correctly place the NGT through all the checklist items was statistically significant in the AR group compared with the control group (P = 0.011). Eighty-six percent of participants in the AR group rated AR as superior/far superior to other procedural training programs to which they had been exposed, whereas, only 5.9% of participants in the control group rated the control program as superior/far superior (P < 0.001). Overall the AR module was better received compared with the control group with regards to realism, identifying landmarks, visualization of internal organs, ease of use, usefulness, and promoting learning and understanding.

  15. Mercury interactions in a simulated gold platter

    Energy Technology Data Exchange (ETDEWEB)

    Miller, J.W. [University of North Carolina, Asheville, NC (United States). Dept. of Environmental Studies; Callahan, J.E. [Appalachian State Univ., Boone, NC (United States). Dept. of Geology; Craig, J.R. [Virginia Polytechnic Institute and State University, Blacksburg, VA (United States). Dept. of Geological Sciences

    2002-07-01

    A simulated stream sediment bed was constructed in a laboratory to determine whether dissolved Hg could be transported through sediment and deposited as amalgam on Au grains. Metallic Hg was placed in a sump at one end of a tank filled with gravel (quartz sand, granules, and pebbles), and Au grains were buried in the gravel at the other end. Water was circulated in a continuous closed loop over the Hg and through the gravel that included the Au grains for more than 850 days. The Hg content of the water increased from nil at the beginning to approximately 0.5 {mu}g/l after approximately 22 days. The Hg content on the rims of Au grains went from nil to approximately 0.2 wt.% over 22 days reaching a maximum 0.48 wt.% Hg after 14 days. Subsequent measurements indicated a persistent decrease of the maximum Hg on Au grains to {<=}0.19 wt.% Hg at 552 days and to {<=}0.05 wt.% at 851 days. Deposition of Hg on the Au grains indicates that amalgams can form without actual contact of Hg on Au in stream sediments. Why Hg first deposited on Au and then dissolved from the Au is unknown, but a paucity of microbiota early in the experiment and subsequent development of microbiota that could facilitate dissolution of Hg is suspected. The simulated Au placer, with its coarse sediments and free water flow, is analogous to streams that have measurable (>0.2 {mu}g/l) Hg in the water and no amalgams on Au grains within the sediments. An example of a Au mining region with similar water concentrations of Hg would be the Amazon Basin, although information on the presence of amalgam rims on Au grains is lacking, as for most regions. Lower but still measurable ({<=}0.55 {mu}g/l Hg) concentrations of Hg in stream water and a lack of amalgams on Au grains occur in Au placers near Talladega, Alabama. The opposite case would be streams with less-than-measurable (<0.2 {mu}g/l) Hg in the water but amalgams on Au grains, where conditions are less aerated and Hg would be more likely to remain in the

  16. The simulation approach to lipid-protein interactions.

    Science.gov (United States)

    Paramo, Teresa; Garzón, Diana; Holdbrook, Daniel A; Khalid, Syma; Bond, Peter J

    2013-01-01

    The interactions between lipids and proteins are crucial for a range of biological processes, from the folding and stability of membrane proteins to signaling and metabolism facilitated by lipid-binding proteins. However, high-resolution structural details concerning functional lipid/protein interactions are scarce due to barriers in both experimental isolation of native lipid-bound complexes and subsequent biophysical characterization. The molecular dynamics (MD) simulation approach provides a means to complement available structural data, yielding dynamic, structural, and thermodynamic data for a protein embedded within a physiologically realistic, modelled lipid environment. In this chapter, we provide a guide to current methods for setting up and running simulations of membrane proteins and soluble, lipid-binding proteins, using standard atomistically detailed representations, as well as simplified, coarse-grained models. In addition, we outline recent studies that illustrate the power of the simulation approach in the context of biologically relevant lipid/protein interactions.

  17. Building Interactive Simulations in Web Pages without Programming.

    Science.gov (United States)

    Mailen Kootsey, J; McAuley, Grant; Bernal, Julie

    2005-01-01

    A software system is described for building interactive simulations and other numerical calculations in Web pages. The system is based on a new Java-based software architecture named NumberLinX (NLX) that isolates each function required to build the simulation so that a library of reusable objects could be assembled. The NLX objects are integrated into a commercial Web design program for coding-free page construction. The model description is entered through a wizard-like utility program that also functions as a model editor. The complete system permits very rapid construction of interactive simulations without coding. A wide range of applications are possible with the system beyond interactive calculations, including remote data collection and processing and collaboration over a network.

  18. Hybrid Simulations of Plasma-Neutral-Dust Interactions at Enceladus

    International Nuclear Information System (INIS)

    Omidi, N.; Russell, C. T.; Jia, Y. D.; Tokar, R. L.; Farrell, W. M.; Kurth, W. S.; Gurnett, D. A.; Leisner, J. S.

    2010-01-01

    Through ejection from its southern hemisphere, Enceladus is a dominant source of neutral gas and dust in Saturn's inner magnetosphere. The interaction of the corotating plasma with the gas and dust modifies the plasma environment around Enceladus. We use 3-D hybrid (kinetic ions, fluid electrons) simulations to examine the effects of gas and dust on the nature of the interaction region and use Cassini observations to constrain their properties.

  19. Monte Carlo simulations of interacting particle mixtures in ratchet potentials

    International Nuclear Information System (INIS)

    Fendrik, A J; Romanelli, L

    2012-01-01

    There are different models of devices for achieving a separation of mixtures of particles by using the ratchet effect. On the other hand, it has been proposed that one could also control the separation by means of appropriate interactions. Through Monte Carlo simulations, we show that inclusion of simple interactions leads to a decrease of the ratchet effect and therefore also a separation of the mixtures.

  20. Simulation of flame-vortex interaction using detailed and reduced

    Energy Technology Data Exchange (ETDEWEB)

    Hilka, M. [Gaz de France (GDF), 75 - Paris (France); Veynante, D. [Ecole Centrale de Paris, Laboratoire EM2C. CNRS, 92 - Chatenay-Malabry (France); Baum, M. [CERFACS (France); Poinsot, T.J. [Centre National de la Recherche Scientifique (CNRS), 45 - Orleans-la-Source (France). Institut de Mecanique des Fluides de Toulouse

    1996-12-31

    The interaction between a pair of counter-rotating vortices and a lean premixed CH{sub 4}/O{sub 2}/N{sub 2} flame ({Phi} = + 0.55) has been studied by direct numerical simulations using detailed and reduced chemical reaction schemes. Results from the complex chemistry simulation are discussed with respect to earlier experiments and differences in the simulations using detailed and reduces chemistry are investigated. Transient evolutions of the flame surface and the total heat release rate are compared and modifications in the evolution of the local flame structure are displayed. (authors) 22 refs.

  1. Long-range interactions and parallel scalability in molecular simulations

    NARCIS (Netherlands)

    Patra, M.; Hyvönen, M.T.; Falck, E.; Sabouri-Ghomi, M.; Vattulainen, I.; Karttunen, M.E.J.

    2007-01-01

    Typical biomolecular systems such as cellular membranes, DNA, and protein complexes are highly charged. Thus, efficient and accurate treatment of electrostatic interactions is of great importance in computational modeling of such systems. We have employed the GROMACS simulation package to perform

  2. Simulation of the interaction between uranium dioxide and zircaloy

    International Nuclear Information System (INIS)

    Denis, A.; Garcia, E.A.

    1984-01-01

    The code solves the oxygen diffusion equations of the five phases formed during the UO 2 /Zircaloy interaction, using an implicit finite difference method with parabolic interpolation at the interfaces. Uranium and Zirconium mass conservation are considered. The code gives a good simulation of the experimental results for isothermal conditions. (orig.)

  3. Two dimensional simulation of ion beam-plasm interaction | Echi ...

    African Journals Online (AJOL)

    Hybrid plasma simulation is a model in which different components of the plasma are treated differently. In this work the ions are treated as particles while the electrons are treated as a neutralizing background fluid through which electric signals may propagate. Deuterium ion beams incident on the tritium plasma interact ...

  4. The role of light for fish-zooplankton-phytoplankton interactions during winter in shallow lakes - a climate change perspective

    DEFF Research Database (Denmark)

    Bramm, Mette Elisabeth; Lassen, Majbritt Kjeldahl; Liboriussen, Lone

    2009-01-01

    in the life history of copepods. The strength of the fish effect on zooplankton biomass diminished with declining light and the effect of light was strongest in the presence of fish. 4. When fish were present, reduced light led to a shift from rotifers to calanoid copepods in the clear lake and from rotifers...... in winter light conditions are needed in order to have a significant effect on the plankton community. The change in light occurring when such plankton communities move northwards in response to global warming will mostly be of modest importance for this lake type, at least for the rest of this century...

  5. Winter Wonderlands

    Science.gov (United States)

    Coy, Mary

    2011-01-01

    Listening to people complain about the hardships of winter and the dreariness of the nearly constant gray sky prompted the author to help her sixth graders recognize and appreciate the beauty that surrounds them for nearly five months of the year in western New York. The author opines that if students could see things more artistically, the winter…

  6. Towards Real Time Simulation of Ship-Ship Interaction

    DEFF Research Database (Denmark)

    Lindberg, Ole; Bingham, Harry B.; Engsig-Karup, Allan Peter

    2012-01-01

    We present recent and preliminary work directed towards the development of a simplified, physics-based model for improved simulation of ship-ship interaction that can be used for both analysis and real-time computing (i.e. with real-time constraints due to visualization). The goal is to implement...... accurate (realistic) and much faster ship-wave and ship-ship simulations than are currently possible. The coupling of simulation with visualization should improve the visual experience such that it can be perceived as more realistic in training. Today the state-of-art in real-time ship-ship interaction...... is for efficiency reasons and time-constraints in visualization based on model experiments in towing tanks and precomputed force tables. We anticipate that the fast, and highly parallel, algorithm described by Engsig-Karup et al. [2011] for execution on affordable modern high-throughput Graphics Processing Units...

  7. Accounting for anthropic energy flux of traffic in winter urban road surface temperature simulations with the TEB model

    Science.gov (United States)

    Khalifa, A.; Marchetti, M.; Bouilloud, L.; Martin, E.; Bues, M.; Chancibaut, K.

    2016-02-01

    Snowfall forecasts help winter maintenance of road networks, ensure better coordination between services, cost control, and a reduction in environmental impacts caused by an inappropriate use of de-icers. In order to determine the possible accumulation of snow on pavements, forecasting the road surface temperature (RST) is mandatory. Weather outstations are used along these networks to identify changes in pavement status, and to make forecasts by analyzing the data they provide. Physical numerical models provide such forecasts, and require an accurate description of the infrastructure along with meteorological parameters. The objective of this study was to build a reliable urban RST forecast with a detailed integration of traffic in the Town Energy Balance (TEB) numerical model for winter maintenance. The study first consisted in generating a physical and consistent description of traffic in the model with two approaches to evaluate traffic incidence on RST. Experiments were then conducted to measure the effect of traffic on RST increase with respect to non-circulated areas. These field data were then used for comparison with the forecast provided by this traffic-implemented TEB version.

  8. Interactions between crop biomass and development of foliar diseases in winter wheat and the potential to graduate the fungicide dose according to crop biomass

    DEFF Research Database (Denmark)

    Jensen, Peter Kryger; Jørgensen, Lise Nistrup

    2016-01-01

    dose. The study was carried out investigating fungicide dose response controlling foliar diseases in winter wheat at three biomass densities obtained growing the crop at three nitrogen levels and using variable seed rates. Further the field experiments included three fungicide dose rates at each...... biomass level, an untreated control, and 75%, 50% and 33% of the recommended fungicide dose rate and the experiments were replicated for three years. Crop biomass had a significant influence on occurrence of septoria and yellow rust with greater disease severity at increasing crop biomass. In two of three...... years, the interaction of crop biomass and fungicide dose rate had a significant influence on disease severity indicating a biomassdependent dose response. The interaction occurred in the two years with high yield potential in combination with severe disease attack. If the variation in crop density...

  9. Optimization Model for Web Based Multimodal Interactive Simulations.

    Science.gov (United States)

    Halic, Tansel; Ahn, Woojin; De, Suvranu

    2015-07-15

    This paper presents a technique for optimizing the performance of web based multimodal interactive simulations. For such applications where visual quality and the performance of simulations directly influence user experience, overloading of hardware resources may result in unsatisfactory reduction in the quality of the simulation and user satisfaction. However, optimization of simulation performance on individual hardware platforms is not practical. Hence, we present a mixed integer programming model to optimize the performance of graphical rendering and simulation performance while satisfying application specific constraints. Our approach includes three distinct phases: identification, optimization and update . In the identification phase, the computing and rendering capabilities of the client device are evaluated using an exploratory proxy code. This data is utilized in conjunction with user specified design requirements in the optimization phase to ensure best possible computational resource allocation. The optimum solution is used for rendering (e.g. texture size, canvas resolution) and simulation parameters (e.g. simulation domain) in the update phase. Test results are presented on multiple hardware platforms with diverse computing and graphics capabilities to demonstrate the effectiveness of our approach.

  10. SLiM 2: Flexible, Interactive Forward Genetic Simulations.

    Science.gov (United States)

    Haller, Benjamin C; Messer, Philipp W

    2017-01-01

    Modern population genomic datasets hold immense promise for revealing the evolutionary processes operating in natural populations, but a crucial prerequisite for this goal is the ability to model realistic evolutionary scenarios and predict their expected patterns in genomic data. To that end, we present SLiM 2: an evolutionary simulation framework that combines a powerful, fast engine for forward population genetic simulations with the capability of modeling a wide variety of complex evolutionary scenarios. SLiM achieves this flexibility through scriptability, which provides control over most aspects of the simulated evolutionary scenarios with a simple R-like scripting language called Eidos. An example SLiM simulation is presented to illustrate the power of this approach. SLiM 2 also includes a graphical user interface for simulation construction, interactive runtime control, and dynamic visualization of simulation output, facilitating easy and fast model development with quick prototyping and visual debugging. We conclude with a performance comparison between SLiM and two other popular forward genetic simulation packages. © The Author 2016. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  11. Uncertainty quantification in ion–solid interaction simulations

    Energy Technology Data Exchange (ETDEWEB)

    Preuss, R., E-mail: preuss@ipp.mpg.de; Toussaint, U. von

    2017-02-15

    Within the framework of Bayesian uncertainty quantification we propose a non-intrusive reduced-order spectral approach (polynomial chaos expansion) to the simulation of ion–solid interactions. The method not only reduces the number of function evaluations but provides simultaneously a quantitative measure for which combinations of inputs have the most important impact on the result. It is applied to SDTRIM-simulations (Möller et al., 1988) with several uncertain and Gaussian distributed input parameters (i.e. angle, projectile energy, surface binding energy, target composition) and the results are compared to full-grid based approaches and sampling based methods with respect to reliability, efficiency and scalability.

  12. PIC Simulation of Laser Plasma Interactions with Temporal Bandwidths

    Science.gov (United States)

    Tsung, Frank; Weaver, J.; Lehmberg, R.

    2015-11-01

    We are performing particle-in-cell simulations using the code OSIRIS to study the effects of laser plasma interactions in the presence of temperal bandwidths under conditions relevant to current and future shock ignition experiments on the NIKE laser. Our simulations show that, for sufficiently large bandwidth, the saturation level, and the distribution of hot electrons, can be effected by the addition of temporal bandwidths (which can be accomplished in experiments using smoothing techniques such as SSD or ISI). We will show that temporal bandwidth along play an important role in the control of LPI's in these lasers and discuss future directions. This work is conducted under the auspices of NRL.

  13. Testing advanced driver assistance systems with the interactive driving simulator; Erprobung von Fahrerassistenzsystemen mit dem Interactive Driving Simulator

    Energy Technology Data Exchange (ETDEWEB)

    Friedrichs, A.; Grosse-Kappenberg, S.; Happe, J. [Zentrum fuer Lern- und Wissensmanagement und Lehrstuhl Informatik im Maschinenbau ZLW/IMA der RWTH Aachen (Germany)

    2005-07-01

    The Centre for Learning and Knowledge Management and Department of Computer Science in Engineering of the Technical University Aachen has developed a truck driving simulator which combines a driving simulation as well as traffic flow calculations to the interactive Driving Simulator (InDriveS). In real-time the effects of the driver's behaviour on the surrounding traffic are considered and vice versa. The integrative part of InDriveS is a software-in-the-loop and hardware-in-the-loop development environment. By means of this tool, all phases of development (Analysis, Design, Modelling, Simulation, Implementation as well as Testing and Evaluation) of new vehicle technologies, e.g. Information and Assistance Systems, can be realised in consideration of the road traffic and the driver's behaviour. (orig.)

  14. DSMC simulations of shock interactions about sharp double cones

    Science.gov (United States)

    Moss, James N.

    2001-08-01

    This paper presents the results of a numerical study of shock interactions resulting from Mach 10 flow about sharp double cones. Computations are made by using the direct simulation Monte Carlo (DSMC) method of Bird. The sensitivity and characteristics of the interactions are examined by varying flow conditions, model size, and configuration. The range of conditions investigated includes those for which experiments have been or will be performed in the ONERA R5Ch low-density wind tunnel and the Calspan-University of Buffalo Research Center (CUBRC) Large Energy National Shock (LENS) tunnel.

  15. Developing Models for Embodied Learning with Live Interactive Simulations

    DEFF Research Database (Denmark)

    Gjedde, Lisa

    2014-01-01

    Live simulations may offer a natural form of multimodal learning through embodied action, which can be engaging to a variety of learners and provide a platform for inclusion of special needs learners across the classroom. In this approach to interactive learning, the subject matter is embedded...... learning design is available that provides for interactive and embodied learning, which appeals to the segment of boys that are often difficult to motivate with ordinary uni-modal teaching methods. The paper will present preliminary results from an action research project carried out in collaboration...

  16. Phantom-based interactive simulation system for dental treatment training.

    Science.gov (United States)

    Sae-Kee, Bundit; Riener, Robert; Frey, Martin; Pröll, Thomas; Burgkart, Rainer

    2004-01-01

    In this paper, we propose a new interactive simulation system for dental treatment training. The system comprises a virtual reality environment and a force-torque measuring device to enhance the capabilities of a passive phantom of tooth anatomy in dental treatment training processes. The measuring device is connected to the phantom, and provides essential input data for generating the graphic animations of physical behaviors such as drilling and bleeding. The animation methods of those physical behaviors are also presented. This system is not only able to enhance interactivity and accessibility of the training system compared to conventional methods but it also provides possibilities of recording, evaluating, and verifying the training results.

  17. Simulation of Fuzzy Adaptive PI Controlled Grid Interactive Inverter

    Directory of Open Access Journals (Sweden)

    Necmi ALTIN

    2009-03-01

    Full Text Available In this study, a voltage source grid interactive inverter is modeled and simulated in MATLAB/Simulink. Inverter is designed as current controlled and a fuzzy-PI current controller used for the generation of switching pattern to shape the inverter output current. The grid interactive inverter consists of a line frequency transformer and a LC type filter. Galvanic isolation between the grid and renewable energy source is obtained by the line frequency transformer and LC filter is employed to filter the high frequency harmonic components in current waveform due to PWM switching and to reduce the output current THD. Results of the MATLAB/Simulink simulation show that inverter output current is in sinusoidal waveform and in phase with line voltage, and current harmonics are in the limits of international standards (

  18. Simulation of hypersonic shock wave - laminar boundary layer interactions

    Science.gov (United States)

    Kianvashrad, N.; Knight, D.

    2017-06-01

    The capability of the Navier-Stokes equations with a perfect gas model for simulation of hypersonic shock wave - laminar boundary layer interactions is assessed. The configuration is a hollow cylinder flare. The experimental data were obtained by Calspan-University of Buffalo (CUBRC) for total enthalpies ranging from 5.07 to 21.85 MJ/kg. Comparison of the computed and experimental surface pressure and heat transfer is performed and the computed §ow¦eld structure is analyzed.

  19. Interactive exploration of tokamak turbulence simulations in virtual reality

    International Nuclear Information System (INIS)

    Kerbel, G.D.; Pierce, T.; Milovich, J.L.; Shumaker, D.E.

    1996-01-01

    We have developed an immersive visualization system designed for interactive data exploration as an integral part of our computing environment for studying tokamak turbulence. This system of codes can reproduce the results of simulations visually for scrutiny in real time, interactively and with more realism than ever before. At peak performance, the VR system can present for view some 400 coordinated images per second. The long term vision this approach targets is a open-quote holodeck-like close-quote virtual-reality environment in which one can explore gyrofluid or gyrokinetic plasma simulations interactively and in real time, visually, with concurrent simulations of experimental diagnostic devices. In principle, such a open-quote virtual tokamak close-quote computed environment could be as all encompassing or as focussed as one likes, in terms of the physics involved. The computing framework in one within which a group of researchers can work together to produce a real and identifiable product with easy access to all contributions. This could be our version of NASA's next generation Numerical Wind Tunnel. The principal purpose of this VR capability for Numerical Tokamak simulation is to provide interactive visual experience to help create new ways of understanding aspects of the convective transport processes operating in tokamak fusion experiments. The effectiveness of the visualization method is strongly dependent on the density of frame-to-frame correlation. Below a threshold of this quantity, short term visual memory does not bridge the gap between frames well enough for there to exist a strong visual connection. Above the threshold, evolving structures appear clearly. The visualizations show the 3D structure of vortex evolution and the gyrofluid motion associated with it. We discovered that it was very helpful for visualizing the cross field flows to compress the virtual world in the toroidal angle

  20. Neurosurgical simulation by interactive computer graphics on iPad.

    Science.gov (United States)

    Maruyama, Keisuke; Kin, Taichi; Saito, Toki; Suematsu, Shinya; Gomyo, Miho; Noguchi, Akio; Nagane, Motoo; Shiokawa, Yoshiaki

    2014-11-01

    Presurgical simulation before complicated neurosurgery is a state-of-the-art technique, and its usefulness has recently become well known. However, simulation requires complex image processing, which hinders its widespread application. We explored handling the results of interactive computer graphics on the iPad tablet, which can easily be controlled anywhere. Data from preneurosurgical simulations from 12 patients (4 men, 8 women) who underwent complex brain surgery were loaded onto an iPad. First, DICOM data were loaded using Amira visualization software to create interactive computer graphics, and ParaView, another free visualization software package, was used to convert the results of the simulation to be loaded using the free iPad software KiwiViewer. The interactive computer graphics created prior to neurosurgery were successfully displayed and smoothly controlled on the iPad in all patients. The number of elements ranged from 3 to 13 (mean 7). The mean original data size was 233 MB, which was reduced to 10.4 MB (4.4% of original size) after image processing by ParaView. This was increased to 46.6 MB (19.9%) after decompression in KiwiViewer. Controlling the magnification, transfer, rotation, and selection of translucence in 10 levels of each element were smoothly and easily performed using one or two fingers. The requisite skill to smoothly control the iPad software was acquired within 1.8 trials on average in 12 medical students and 6 neurosurgical residents. Using an iPad to handle the result of preneurosurgical simulation was extremely useful because it could easily be handled anywhere.

  1. Interactive simulations as teaching tools for engineering mechanics courses

    Science.gov (United States)

    Carbonell, Victoria; Romero, Carlos; Martínez, Elvira; Flórez, Mercedes

    2013-07-01

    This study aimed to gauge the effect of interactive simulations in class as an active teaching strategy for a mechanics course. Engineering analysis and design often use the properties of planar sections in calculations. In the stress analysis of a beam under bending and torsional loads, cross-sectional properties are used to determine stress and displacement distributions in the beam cross section. The centroid, moments and products of inertia of an area made up of several common shapes (rectangles usually) may thus be obtained by adding the moments of inertia of the component areas (U-shape, L-shape, C-shape, etc). This procedure is used to calculate the second moments of structural shapes in engineering practice because the determination of their moments of inertia is necessary for the design of structural components. This paper presents examples of interactive simulations developed for teaching the ‘Mechanics and mechanisms’ course at the Universidad Politecnica de Madrid, Spain. The simulations focus on fundamental topics such as centroids, the properties of the moment of inertia, second moments of inertia with respect to two axes, principal moments of inertia and Mohr's Circle for plane stress, and were composed using Geogebra software. These learning tools feature animations, graphics and interactivity and were designed to encourage student participation and engagement in active learning activities, to effectively explain and illustrate course topics, and to build student problem-solving skills.

  2. Stochastic simulation of ecohydrological interactions between vegetation and groundwater

    Science.gov (United States)

    Dwelle, M. C.; Ivanov, V. Y.; Sargsyan, K.

    2017-12-01

    The complex interactions between groundwater and vegetation in the Amazon rainforest may yield vital ecophysiological interactions in specific landscape niches such as buffering plant water stress during dry season or suppression of water uptake due to anoxic conditions. Representation of such processes is greatly impacted by both external and internal sources of uncertainty: inaccurate data and subjective choice of model representation. The models that can simulate these processes are complex and computationally expensive, and therefore make it difficult to address uncertainty using traditional methods. We use the ecohydrologic model tRIBS+VEGGIE and a novel uncertainty quantification framework applied to the ZF2 watershed near Manaus, Brazil. We showcase the capability of this framework for stochastic simulation of vegetation-hydrology dynamics. This framework is useful for simulation with internal and external stochasticity, but this work will focus on internal variability of groundwater depth distribution and model parameterizations. We demonstrate the capability of this framework to make inferences on uncertain states of groundwater depth from limited in situ data, and how the realizations of these inferences affect the ecohydrological interactions between groundwater dynamics and vegetation function. We place an emphasis on the probabilistic representation of quantities of interest and how this impacts the understanding and interpretation of the dynamics at the groundwater-vegetation interface.

  3. Interactive simulations as teaching tools for engineering mechanics courses

    International Nuclear Information System (INIS)

    Carbonell, Victoria; Martínez, Elvira; Flórez, Mercedes; Romero, Carlos

    2013-01-01

    This study aimed to gauge the effect of interactive simulations in class as an active teaching strategy for a mechanics course. Engineering analysis and design often use the properties of planar sections in calculations. In the stress analysis of a beam under bending and torsional loads, cross-sectional properties are used to determine stress and displacement distributions in the beam cross section. The centroid, moments and products of inertia of an area made up of several common shapes (rectangles usually) may thus be obtained by adding the moments of inertia of the component areas (U-shape, L-shape, C-shape, etc). This procedure is used to calculate the second moments of structural shapes in engineering practice because the determination of their moments of inertia is necessary for the design of structural components. This paper presents examples of interactive simulations developed for teaching the ‘Mechanics and mechanisms’ course at the Universidad Politecnica de Madrid, Spain. The simulations focus on fundamental topics such as centroids, the properties of the moment of inertia, second moments of inertia with respect to two axes, principal moments of inertia and Mohr's Circle for plane stress, and were composed using Geogebra software. These learning tools feature animations, graphics and interactivity and were designed to encourage student participation and engagement in active learning activities, to effectively explain and illustrate course topics, and to build student problem-solving skills. (paper)

  4. A treecode to simulate dust-plasma interactions

    Science.gov (United States)

    Thomas, D. M.; Holgate, J. T.

    2017-02-01

    The interaction of a small object with surrounding plasma is an area of plasma-physics research with a multitude of applications. This paper introduces the plasma octree code pot, a microscopic simulator of a spheroidal dust grain in a plasma. pot uses the Barnes-Hut treecode algorithm to perform N-body simulations of electrons and ions in the vicinity of a chargeable spheroid, employing also the Boris particle-motion integrator and Hutchinson’s reinjection algorithm from SCEPTIC; a description of the implementation of all three algorithms is provided. We present results from pot simulations of the charging of spheres in magnetised plasmas, and of spheroids in unmagnetized plasmas. The results call into question the validity of using the Boltzmann relation in hybrid PIC codes. Substantial portions of this paper are adapted from chapters 4 and 5 of the first author’s recent PhD dissertation.

  5. Simulation of intense short-pulse laser-plasma interaction

    International Nuclear Information System (INIS)

    Yamagiwa, Mitsuru

    2000-01-01

    We have completed the massive parallelization of a 2-dimensional giga-particle code and have achieved a 530-fold acceleration rate with 512 processing elements (PE's). Using this we have implemented a simulation of the interaction of a solid thin film and a high intensity laser and have discovered a phenomenon in which high quality short pulses from the far ultraviolet to soft X-rays are generated at the back surface of the thin layer. We have also introduced the atomic process database code (Hullac) and have the possibility for high precision simulations of X-ray laser radiation. With respect to laser acceleration we have the possibility to quantitatively evaluate relativistic self-focusing assumed to occur in higher intensity fields. Ion acceleration from a solid target and an underdense plasma irradiated by an intense and an ultra intense laser, respectively, has also been studied by particle-in-cell (PIC) simulations. (author)

  6. Two dimensional simulation of high power laser-surface interaction

    International Nuclear Information System (INIS)

    Goldman, S.R.; Wilke, M.D.; Green, R.E.L.; Johnson, R.P.; Busch, G.E.

    1998-01-01

    For laser intensities in the range of 10 8 --10 9 W/cm 2 , and pulse lengths of order 10 microsec or longer, the authors have modified the inertial confinement fusion code Lasnex to simulate gaseous and some dense material aspects of the laser-matter interaction. The unique aspect of their treatment consists of an ablation model which defines a dense material-vapor interface and then calculates the mass flow across this interface. The model treats the dense material as a rigid two-dimensional mass and heat reservoir suppressing all hydrodynamic motion in the dense material. The computer simulations and additional post-processors provide predictions for measurements including impulse given to the target, pressures at the target interface, electron temperatures and densities in the vapor-plasma plume region, and emission of radiation from the target. The authors will present an analysis of some relatively well diagnosed experiments which have been useful in developing their modeling. The simulations match experimentally obtained target impulses, pressures at the target surface inside the laser spot, and radiation emission from the target to within about 20%. Hence their simulational technique appears to form a useful basis for further investigation of laser-surface interaction in this intensity, pulse-width range. This work is useful in many technical areas such as materials processing

  7. Sustainable Block Design Process for High-Rise and High-Density Districts with Snow and Wind Simulations for Winter Cities

    Directory of Open Access Journals (Sweden)

    Norihiro Watanabe

    2017-11-01

    Full Text Available Urban designs that consider regional climatic conditions are one of the most important approaches for developing sustainable cities. In cities that suffer from heavy snow and cold winds in winter, an urban design approach different than that used for warm cities should be used. This study presents a scientific design process (the sustainable design approach that incorporates environmental and energy assessments that use snow and wind simulations to establish guidelines for the design of urban blocks in high-rise and high-density districts so that the impact of snow and wind can be minimized in these cities. A city block in downtown Sapporo, Japan, was used as a case study, and we evaluated four conceptual models. The four models were evaluated for how they impacted the snow and wind conditions in the block as well as the snow removal energy. Based on the results, we were able to identify the design guidelines in downtown Sapporo: an urban block design with higher building height ratio without the mid-rise part can reduce the snowdrifts and lower the snow removal energy. The proposed sustainable urban design approach would be effective in improving the quality of public spaces and reducing snow removal energy in winter cities.

  8. Interactive Role of Fungicides and Plant Growth Regulator (Trinexapac on Seed Yield and Oil Quality of Winter Rapeseed

    Directory of Open Access Journals (Sweden)

    Muhammad Ijaz

    2015-09-01

    Full Text Available This study was designed to evaluate the role of growth regulator trinexapac and fungicides on growth, yield, and quality of winter rapeseed (Brassica napus L.. The experiment was conducted simultaneously at different locations in Germany using two cultivars of rapeseed. Five different fungicides belonging to the triazole and strobilurin groups, as well as a growth regulator trinexapac, were tested in this study. A total of seven combinations of these fungicides and growth regulator trinexapac were applied at two growth stages of rapeseed. These two stages include green floral bud stage (BBCH 53 and the course of pod development stage (BBCH 65. The results showed that plant height and leaf area index were affected significantly by the application of fungicides. Treatments exhibited induced photosynthetic ability and delayed senescence, which improved the morphological characters and yield components of rape plants at both locations. Triazole, in combination with strobilurin, led to the highest seed yield over other treatments at both experimental locations. Significant effects of fungicides on unsaturated fatty acids of rapeseed oil were observed. Fungicides did not cause any apparent variation in the values of free fatty acids and peroxide of rapeseed oil. Results of our study demonstrate that judicious use of fungicides in rapeseed may help to achieve sustainable farming to obtain higher yield and better quality of rapeseed.

  9. Simulator: A Pilot Interactive Simulation Program for Use in Teaching Public Relations.

    Science.gov (United States)

    Pavlik, John V.

    An interactive simulation program was developed for use in teaching students how to handle public relations problems. The program user is placed in the role of assistant newsletter editor, facing a series of decision-making situations. Each choice the user makes affects the subsequent reality created by the program, which is designed to provide…

  10. Thermodynamical analyses of molecular simulations of dislocation-defect interactions: simulations at 0 K

    International Nuclear Information System (INIS)

    Monnet, G.

    2008-01-01

    Full text of publication follows. Static molecular (SM) simulations of dislocation-defect interaction are analysed through a framework of different interaction regimes, in which the applied work has different roles. In most regimes, the applied work is transformed into elastic energy, a dissipative energy resulting from the lattice friction and a large quantity of energy needed to enable the dislocation to bow out when it is pinned by the defect. While the dissipative work is entirely evacuated in SM simulations, the elastic and curvature energies contribute to a large increase of the internal energy of the system. A method is presented in this work to evaluate the curvature energy and the result is compared to prediction of the line tension model. These analyses allow the determination of the dislocation-defect interaction energy. (author)

  11. Chemical interaction of tetravalent actinides simulators and the engineering barrier

    International Nuclear Information System (INIS)

    Chain, Pablo; Alba, Maria D.; Castro, Miguel A.; Pavon, Esperanza; Mar Orta, M.

    2010-01-01

    Document available in extended abstract form only. The Deep Geological Repository (DGR) is the most internationally accepted option for the storage of high radioactive wastes. This confinement is based on the Multi-barrier Concept where the engineered barrier is a crucial safety wise. Nowadays, bentonite is accepted as the best argillaceous material in the engineered barrier of DGR. Additionally to its well-known physical role, a chemical interaction between lutetium, as actinide simulator, and the smectite has been demonstrated. The existence of a reaction mechanism, which was not previously described, based on the chemical interaction between the lanthanide cations and the orthosilicate anions of the lamellar structure has been identified. This finding has aroused the interest of the scientific community because lanthanides are used as simulators of high activity radionuclide (HAR) in agreement with the guidelines established in the bibliography. It has been observed that in conditions of moderate temperature and pressure a chemical interaction exists between smectites and rare earth elements (RE) and phases of insoluble di-silicate, RE 2 Si 2 O 7 , which would immobilize RE, are generated. It is remarkable that the reaction extends to all the set of the smectites, although they do not display the same reactivity, the saponite being the most reactive. The main isotopes present in the HLW belong to the actinide elements Np, Pu, Am and Cm, in addition to uranium generated by neutron capture during the fuel combustion process. The study of the mobilization of actinide (IV) thorough the bentonite barrier is limited because of their radioactivity. However, U(IV), Np(IV), Pu(IV) and Th(IV) can be simulated by the stable isotopes of the Zr(IV) and Hf(IV), because they exhibit ionic radius and physicochemical properties very similar to those of the actinide elements. It is the main objective of this research to investigate the chemical interaction of Zr(IV) as actinide

  12. Simulations of Shock Wave Interaction with a Particle Cloud

    Science.gov (United States)

    Koneru, Rahul; Rollin, Bertrand; Ouellet, Frederick; Annamalai, Subramanian; Balachandar, S.'Bala'

    2016-11-01

    Simulations of a shock wave interacting with a cloud of particles are performed in an attempt to understand similar phenomena observed in dispersal of solid particles under such extreme environment as an explosion. We conduct numerical experiments in which a particle curtain fills only 87% of the shock tube from bottom to top. As such, the particle curtain upon interaction with the shock wave is expected to experience Kelvin-Helmholtz (KH) and Richtmyer-Meshkov (RM) instabilities. In this study, the initial volume fraction profile matches with that of Sandia Multiphase Shock Tube experiments, and the shock Mach number is limited to M =1.66. In these simulations we use a Eulerian-Lagrangian approach along with state-of-the-art point-particle force and heat transfer models. Measurements of particle dispersion are made at different initial volume fractions of the particle cloud. A detailed analysis of the evolution of the particle curtain with respect to the initial conditions is presented. This work was supported by the U.S. Department of Energy, National Nuclear Security Administration, Advanced Simulation and Computing Program, as a Cooperative Agreement under the Predictive Science Academic Alliance Program, Contract No. DE-NA0002378.

  13. Shear flow - Structure interaction phenomena; Proceedings of the winter annual meeting, Miami Beach, FL, November 17-22, 1985

    International Nuclear Information System (INIS)

    Akay, A.; Reischman, M.

    1985-01-01

    Papers are presented on frequency-wavenumber spectral estimation of the wall-pressure field beneath a turbulent boundary layer, spectral distribution measurements of turbulent boundary layer pressure fields, measurements of fluctuating wall pressure for separated/reattached boundary layer flows, recent progress on trailing-edge/end interactions and instabilities, and the effects of compliant walls on transition and turbulence. Consideration is also given to the generation of wave patterns on a compliant surface by turbulent boundary layer pressure, boundary layer interactions with compliant coatings, an assessment of some vorticity field-leading edge interactions, an experimental study of the flow and wall-pressure field around a wind-body junction, and pressure cross-spectra in turbulent boundary layers in water

  14. Embedding a Virtual Patient Simulator in an Interactive Surgical lecture.

    Science.gov (United States)

    Kleinert, Robert; Plum, Patrick; Heiermann, Nadine; Wahba, Roger; Chang, De-Huan; Hölscher, Arnulf H; Stippel, Dirk L

    2016-01-01

    Lectures are traditionally used for teaching declarative knowledge. One established tool for clinical education is the demonstration of a real patient. The use of real patients in the daily clinical environment is increasingly difficult. The use of a virtual patient simulator (VPS) can potentially circumvent these problems. Unlimited availability and the opportunity of an electronic feedback system could possibly enrich traditional lectures by enabling more interactivity that meets the expectations of the current student generation. As students face the consequences of their own decisions they take a more active role in the lecture. VPS links declarative knowledge with visual perception that is known to influence students' motivation. Until now, there have been no reports covering the usage and validation of interactive VPS for supporting traditional lectures. In this study, we (1) described the development of a custom-made three-dimensional (3D) VPS for supporting the traditional lecture and (2) performed a feasibility study including an initial assessment of this novel educational concept. Conceptualization included definition of curricular content, technical realization and validation. A custom-made simulator was validated with 68 students. The degree of student acceptance was evaluated. Furthermore, the effect on knowledge gain was determined by testing prelecture and postlecture performance. A custom-made simulator prototype that displays a 3D virtual clinic environment was developed and linked to a PowerPoint presentation. Students were able to connect to the simulator via electronic devices (smartphones and tablets) and to control the simulator via majority vote. The simulator was used in 6 lectures and validated in 2 lectures with 68 students each. Student acceptance and their opinion about effectiveness and applicability were determined. Students showed a high level of motivation when using the simulator as most of them had fun using it. Effect on

  15. Simulation of Coulomb interaction effects in electron sources

    International Nuclear Information System (INIS)

    Rouse, John; Zhu Xieqing; Liu Haoning; Munro, Eric

    2011-01-01

    Over many years, we have developed electron source simulation software that has been used widely in the electron optics community to aid the development of rotationally symmetric electron and ion guns. The simulation includes the modelling of cathode emission and the effects of volumetric space charge. In the present paper we describe the existing software and explain how we have extended this software to include the effects of discrete Coulomb interactions between the electrons as they travel from the cathode surface to the exit of the gun. In the paper, we will describe the numerical models we have employed, the techniques we have used to maximize the speed of the Coulomb force computation and present several illustrative examples of cases analyzed using the new software, including thermal field emitters, LaB 6 guns and flat dispenser-type cathodes.

  16. Audio-haptic interaction in simulated walking experiences

    DEFF Research Database (Denmark)

    Serafin, Stefania

    2011-01-01

    and interchangeable use of the haptic and auditory modality in floor interfaces, and for the synergy of perception and action in capturing and guiding human walking. We describe the technology developed in the context of this project, together with some experiments performed to evaluate the role of auditory......In this paper an overview of the work conducted on audio-haptic physically based simulation and evaluation of walking is provided. This work has been performed in the context of the Natural Interactive Walking (NIW) project, whose goal is to investigate possibilities for the integrated...... and haptic feedback in walking tasks....

  17. Light & Skin Interactions Simulations for Computer Graphics Applications

    CERN Document Server

    Baranoski, Gladimir V G

    2010-01-01

    Light and Skin Interactions immerses you in one of the most fascinating application areas of computer graphics: appearance simulation. The book first illuminates the fundamental biophysical processes that affect skin appearance, and reviews seminal related works aimed at applications in life and health sciences. It then examines four exemplary modeling approaches as well as definitive algorithms that can be used to generate realistic images depicting skin appearance. An accompanying companion site also includes complete code and data sources for the BioSpec model, which is considered to be the

  18. Numerical simulation of bosonic-superconducting-string interactions

    International Nuclear Information System (INIS)

    Laguna, P.; Matzner, R.A.

    1990-01-01

    Numerical simulations show that bosonic superconducting U(1) gauge cosmic strings interact by reconnecting and chopping off in a fashion similar to nonconducting strings. Cancellation of the electromagnetic current occurs when, in one of the strings, the direction of the U(1) gauge magnetic field is opposite to the electromagnetic current flow. Electric charge accumulates on the segments of the reconnected strings where the current is discontinuous or vanishes. A virtual photon appears after the collision and intercommutation, and a bubble of electromagnetic radiation emerges as the currents in the reconnected strings equalize. These phenomena suggest new possible mechanisms for void production in the large-scale distribution of galaxies

  19. Working with simulated forms of interaction in health care education

    DEFF Research Database (Denmark)

    Nordentoft, Helle Merete; Olesen, Lektor Birgitte Ravn

    This paper argues that role-play as a simulated form of interaction - live and performed on video - is a creative method which has the potential to generate and support authentic dialogues in practice. In the paper we draw on experiences from 6 interdisciplinary workshops at a Danish hospital...... in which role-play of practice situations - both live and performed on video - formed the launching-pad for participants’ oral and written reflections. Our findings show that role-play has the potential to 1) develop professionals’ sensitivity to the significance of unexpected, embodied and emotional...

  20. Boundary Slip and Surface Interaction: A Lattice Boltzmann Simulation

    International Nuclear Information System (INIS)

    Yan-Yan, Chen; Hua-Bing, Li; Hou-Hui, Yi

    2008-01-01

    The factors affecting slip length in Couette geometry flows are analysed by means of a two-phase mesoscopic lattice Boltzmann model including non-ideal fluid-fluid and fluid-wall interactions. The main factors influencing the boundary slip are the strength of interactions between fluid-fluid and fluid-wall particles. Other factors, such as fluid viscosity, bulk pressure may also change the slip length. We find that boundary slip only occurs under a certain density (bulk pressure). If the density is large enough, the slip length will tend to zero. In our simulations, a low density layer near the wall does not need to be postulated a priori but emerges naturally from the underlying non-ideal mesoscopic dynamics. It is the low density layer that induces the boundary slip. The results may be helpful to understand recent experimental observations on the slippage of micro flows

  1. Simulation of laser-target interactions in a vacuum

    International Nuclear Information System (INIS)

    Goldman, S.R.; Gitomer, S.L.; Kopp, R.A.; Saltzman, J.S.; Dingus, R.S.

    1985-01-01

    This paper presents numerical simulations for two problem classes. First we study (and compare against one-dimensional analogues) the two dimensional azimuthally symmetric interaction appropriate to a laser pulse energy of order 100 joules, flat-top pulse of width 50 nanoseconds, and wavelength of 0.25 μm, with intensities ranging from 2 x 10 9 W/cm 2 to 2 x 10 12 W/cm 2 . These conditions correspond to an experimental series shot on the Sprite laser at the Rutherford-Appleton Laboratory during the summer of 1985. Next we study the interaction, especially as concerns momentum coupling, for one-dimensional nondiverging geometry, at laser wavelengths of 0.25 μm and 10.6 μm and flat-topped pulsewidths of 1 μsec, with intensities ranging from 10 9 to 10 12 W/cm 2 . In all cases, calculations are for aluminum targets in vacuum

  2. Molecular dynamics simulations of lipid bilayers : major artifacts due to truncating electrostatic interactions

    NARCIS (Netherlands)

    Patra, M.; Karttunen, M.E.J.; Hyvönen, M.T.; Falck, E.; Lindqvist, P.; Vattulainen, I.

    2003-01-01

    We study the influence of truncating the electrostatic interactions in a fully hydrated pure dipalmitoylphosphatidylcholine (DPPC) bilayer through 20 ns molecular dynamics simulations. The computations in which the electrostatic interactions were truncated are compared to similar simulations using

  3. A Graphical Interactive Simulation Environment for Production Planning in Bacon Factories

    DEFF Research Database (Denmark)

    Nielsen, Kirsten Mølgaard; Nielsen, Jens Frederik Dalsgaard

    1994-01-01

    The paper describes a graphical interactive simulation tool for production planning in bacon factories........The paper describes a graphical interactive simulation tool for production planning in bacon factories.....

  4. SIMUL - a program for the simulation of interactions in the streamer chamber RISK

    International Nuclear Information System (INIS)

    Friebel, W.; Gajewski, J.; Halm, I.

    1976-08-01

    A program for the simulation of interactions in the streamer chamber RISK is described. This program allows first investigations and tests for planning and preparing experiments. In the program the trajectories of all particles taking part in the interaction are computed. Selected points are projected onto film planes serving as measurement points for the use in the geometrical reconstruction. The program is used for testing a geometry program. But it also seems to be very helpful in investigating counter and trigger constellations and in the calculation of counting rates and trigger effectivities. (author)

  5. AXISYMMETRIC SIMULATIONS OF HOT JUPITER–STELLAR WIND HYDRODYNAMIC INTERACTION

    International Nuclear Information System (INIS)

    Christie, Duncan; Arras, Phil; Li, Zhi-Yun

    2016-01-01

    Gas giant exoplanets orbiting at close distances to the parent star are subjected to large radiation and stellar wind fluxes. In this paper, hydrodynamic simulations of the planetary upper atmosphere and its interaction with the stellar wind are carried out to understand the possible flow regimes and how they affect the Lyα transmission spectrum. Following Tremblin and Chiang, charge exchange reactions are included to explore the role of energetic atoms as compared to thermal particles. In order to understand the role of the tail as compared to the leading edge of the planetary gas, the simulations were carried out under axisymmetry, and photoionization and stellar wind electron impact ionization reactions were included to limit the extent of the neutrals away from the planet. By varying the planetary gas temperature, two regimes are found. At high temperature, a supersonic planetary wind is found, which is turned around by the stellar wind and forms a tail behind the planet. At lower temperatures, the planetary wind is shut off when the stellar wind penetrates inside where the sonic point would have been. In this regime mass is lost by viscous interaction at the boundary between planetary and stellar wind gases. Absorption by cold hydrogen atoms is large near the planetary surface, and decreases away from the planet as expected. The hot hydrogen absorption is in an annulus and typically dominated by the tail, at large impact parameter, rather than by the thin leading edge of the mixing layer near the substellar point

  6. AXISYMMETRIC SIMULATIONS OF HOT JUPITER–STELLAR WIND HYDRODYNAMIC INTERACTION

    Energy Technology Data Exchange (ETDEWEB)

    Christie, Duncan; Arras, Phil; Li, Zhi-Yun [Department of Astronomy, University of Virginia, Charlottesville, VA 22904 (United States)

    2016-03-20

    Gas giant exoplanets orbiting at close distances to the parent star are subjected to large radiation and stellar wind fluxes. In this paper, hydrodynamic simulations of the planetary upper atmosphere and its interaction with the stellar wind are carried out to understand the possible flow regimes and how they affect the Lyα transmission spectrum. Following Tremblin and Chiang, charge exchange reactions are included to explore the role of energetic atoms as compared to thermal particles. In order to understand the role of the tail as compared to the leading edge of the planetary gas, the simulations were carried out under axisymmetry, and photoionization and stellar wind electron impact ionization reactions were included to limit the extent of the neutrals away from the planet. By varying the planetary gas temperature, two regimes are found. At high temperature, a supersonic planetary wind is found, which is turned around by the stellar wind and forms a tail behind the planet. At lower temperatures, the planetary wind is shut off when the stellar wind penetrates inside where the sonic point would have been. In this regime mass is lost by viscous interaction at the boundary between planetary and stellar wind gases. Absorption by cold hydrogen atoms is large near the planetary surface, and decreases away from the planet as expected. The hot hydrogen absorption is in an annulus and typically dominated by the tail, at large impact parameter, rather than by the thin leading edge of the mixing layer near the substellar point.

  7. THIEF: An interactive simulation of nuclear materials safeguards

    Energy Technology Data Exchange (ETDEWEB)

    Stanbro, W. D.

    1990-01-01

    The safeguards community is facing an era in which it will be called upon to tighten protection of nuclear material. At the same time, it is probable that safeguards will face more competition for available resources from other activities such as environmental cleanup. To exist in this era, it will be necessary to understand and coordinate all aspects of the safeguards system. Because of the complexity of the interactions involved, this process puts a severe burden on designers and operators of safeguards systems. This paper presents a simulation tool developed at the Los Alamos National Laboratory to allow users to examine the interactions among safeguards elements as they apply to combating the insider threat. The tool consists of a microcomputer-based simulation in which the user takes the role of the insider trying to remove nuclear material from a facility. The safeguards system is run by the computer and consists of both physical protection and MC A computer elements. All data elements describing a scenario can be altered by the user. The program can aid in training, as well as in developing threat scenarios. 4 refs.

  8. Building interactive simulations in a Web page design program.

    Science.gov (United States)

    Kootsey, J Mailen; Siriphongs, Daniel; McAuley, Grant

    2004-01-01

    A new Web software architecture, NumberLinX (NLX), has been integrated into a commercial Web design program to produce a drag-and-drop environment for building interactive simulations. NLX is a library of reusable objects written in Java, including input, output, calculation, and control objects. The NLX objects were added to the palette of available objects in the Web design program to be selected and dropped on a page. Inserting an object in a Web page is accomplished by adding a template block of HTML code to the page file. HTML parameters in the block must be set to user-supplied values, so the HTML code is generated dynamically, based on user entries in a popup form. Implementing the object inspector for each object permits the user to edit object attributes in a form window. Except for model definition, the combination of the NLX architecture and the Web design program permits construction of interactive simulation pages without writing or inspecting code.

  9. An interactive beam line simulator module for RHIC

    International Nuclear Information System (INIS)

    MacKay, W.W.

    1997-01-01

    This paper describes the interactive simulation engine, bl, designed for the RHIC project. The program tracks as output to shared memory the central orbit, Twiss and dispersion functions, as well as the 6 x 6 beam hyperellipsoid. Transfer matrices between elements are available via interactive requests. Using a 6-d model, optical elements are modeled with a linear transfer matrix and a vector. The vector allows simulation of misalignments, shifts in field strengths, and beam rigidity. Currently only a linear model is used for elements. In addition to the usual magnets, a foil element is included which can shift the beam's rigidity (resulting from a change of charge and energy loss), as well as increase the momentum spread and emittance. Running as a Glish client, bl can be interfaced to other programs, such as an orbit plotter and a power supply application to give a quick prediction of the beam orbit from actual operating currents in the accelerator. Various strengths and offsets may be changed by sending Glish events to bl

  10. WINTER SAECULUM

    Directory of Open Access Journals (Sweden)

    Emil Mihalina

    2017-03-01

    Full Text Available Accumulated imbalances in the economy and on the markets cause specific financial market dynamics that have formed characteristic patterns kept throughout long financial history. In 2008 Authors presented their expectations of key macroeconomic and selected asset class markets developments for period ahead based on Saeculum theory. Use of term Secular describes a specific valuation environment during prolonged period. If valuations as well as selected macro variables are considered as a tool for understanding business cycles then market cycles become much more obvious and easily understandable. Therefore over the long run, certain asset classes do better in terms of risk reward profile than others. Further on, there is no need for frequent portfolio rebalancing and timing of specific investment positions within a particular asset class market. Current stage in cycle development suggests a need for reassessment of trends and prevailing phenomena due to cyclical nture of long lasting Saeculums. Paper reviews developments in recognizable patterns of selected metrics in current Winter Saeculum dominated with prevailing forces of delivering, deflation and decrease in velocity of money.

  11. Simulations of structure formation in interacting dark energy cosmologies

    International Nuclear Information System (INIS)

    Baldi, M.

    2009-01-01

    The evidence in favor of a dark energy component dominating the Universe, and driving its presently accelerated expansion, has progressively grown during the last decade of cosmological observations. If this dark energy is given by a dynamic scalar field, it may also have a direct interaction with other matter fields in the Universe, in particular with cold dark matter. Such interaction would imprint new features on the cosmological background evolution as well as on the growth of cosmic structure, like an additional long-range fifth-force between massive particles, or a variation in time of the dark matter particle mass. We present here the implementation of these new physical effects in the N-body code GADGET-2, and we discuss the outcomes of a series of high-resolution N-body simulations for a selected family of interacting dark energy models. We interestingly find, in contrast with previous claims, that the inner overdensity of dark matter halos decreases in these models with respect to ΛCDM, and consistently halo concentrations show a progressive reduction for increasing couplings. Furthermore, the coupling induces a bias in the overdensities of cold dark matter and baryons that determines a decrease of the halo baryon fraction below its cosmological value. These results go in the direction of alleviating tensions between astrophysical observations and the predictions of the ΛCDM model on small scales, thereby opening new room for coupled dark energy models as an alternative to the cosmological constant.

  12. Water-use efficiency and relative growth rate mediate competitive interactions in Sonoran Desert winter annual plants.

    Science.gov (United States)

    Gremer, Jennifer R; Kimball, Sarah; Keck, Katie R; Huxman, Travis E; Angert, Amy L; Venable, D Lawrence

    2013-10-01

    A functional approach to investigating competitive interactions can provide a mechanistic understanding of processes driving population dynamics, community assembly, and the maintenance of biodiversity. In Sonoran Desert annual plants, a trade-off between relative growth rate (RGR) and water-use efficiency (WUE) contributes to species differences in population dynamics that promote long-term coexistence. Traits underlying this trade-off explain variation in demographic responses to precipitation as well as life history and phenological patterns. Here, we ask how these traits mediate competitive interactions. • We conducted competition trials for three species occupying different positions along the RGR-WUE trade-off axis and compared the effects of competition at high and low soil moisture. We compared competitive effect (ability to suppress neighbors) and competitive response (ability to withstand competition from neighbors) among species. • The RGR-WUE trade-off predicted shifts in competitive responses at different soil moistures. The high-RGR species was more resistant to competition in high water conditions, while the opposite was true for the high-WUE species. The intermediate RGR species tended to have the strongest impact on all neighbors, so competitive effects did not scale directly with differences in RGR and WUE among competitors. • Our results reveal mechanisms underlying long-term variation in fitness: high-RGR species perform better in years with large, frequent rain events and can better withstand competition under wetter conditions. The opposite is true for high-WUE species. Such resource-dependent responses strongly influence community dynamics and can promote coexistence in variable environments.

  13. Simulating the interaction of jets with the intracluster medium

    Science.gov (United States)

    Weinberger, Rainer; Ehlert, Kristian; Pfrommer, Christoph; Pakmor, Rüdiger; Springel, Volker

    2017-10-01

    Jets from supermassive black holes in the centres of galaxy clusters are a potential candidate for moderating gas cooling and subsequent star formation through depositing energy in the intracluster gas. In this work, we simulate the jet-intracluster medium interaction using the moving-mesh magnetohydrodynamics code arepo. Our model injects supersonic, low-density, collimated and magnetized outflows in cluster centres, which are then stopped by the surrounding gas, thermalize and inflate low-density cavities filled with cosmic rays. We perform high-resolution, non-radiative simulations of the lobe creation, expansion and disruption, and find that its dynamical evolution is in qualitative agreement with simulations of idealized low-density cavities that are dominated by a large-scale Rayleigh-Taylor instability. The buoyant rising of the lobe does not create energetically significant small-scale chaotic motion in a volume-filling fashion, but rather a systematic upward motion in the wake of the lobe and a corresponding back-flow antiparallel to it. We find that, overall, 50 per cent of the injected energy ends up in material that is not part of the lobe, and about 25 per cent remains in the inner 100 kpc. We conclude that jet-inflated, buoyantly rising cavities drive systematic gas motions that play an important role in heating the central regions, while mixing of lobe material is subdominant. Encouragingly, the main mechanisms responsible for this energy deposition can be modelled already at resolutions within reach in future, high-resolution cosmological simulations of galaxy clusters.

  14. Numerical Simulation of the Application of Solar Radiant Systems, Internal Airflow and Occupants’ Presence in the Improvement of Comfort in Winter Conditions

    Directory of Open Access Journals (Sweden)

    Eusébio Z. E. Conceição

    2016-09-01

    Full Text Available In this work, the use of numerical simulation in the application of solar radiant systems, internal airflow and occupants’ presence in the improvement of comfort in winter conditions is made. The thermal comfort, the local thermal discomfort and the air quality in an occupied chamber space are evaluated. In the experimental measurements, a wood chamber, a desk, two seats, two seated hygro-thermal manikins, a warm radiant floor, a solar radiation simulator and a water solar collector are used. The air velocity and the air temperature fluctuation are experimentally evaluated around 15 human body sections. The chamber surface temperature is experimentally measured. In the numerical simulation, a coupling human thermal comfort (HTC integral model, a computational fluids dynamics (CFD differential model and a building thermal response (BTR integral model are applied. The human thermal comfort level is evaluated by the HTC numerical model. The airflow inside the virtual chamber, using the k-epsilon and RNG turbulence models, is evaluated by the CFD numerical model. The chamber surface and the collector temperatures are evaluated by the BTR numerical model. In the human thermal comfort level, in non-uniform environments, the predicted mean vote (PMV and the predicted percentage of dissatisfied (PPD people are numerically evaluated; in the local thermal discomfort level the draught risk (DR is experimentally and numerically analyzed; and in the air quality, the carbon dioxide CO2 concentration is numerically calculated. In the validation tests, the experimental and numerical values of the chamber surface temperature, the air temperature, the air velocity, the air turbulence intensity and the DR are presented.

  15. HYDRUS Simulation of Sustainable Brackish Water Irrigation in a Winter Wheat-Summer Maize Rotation System in the North China Plain

    Directory of Open Access Journals (Sweden)

    Kangkang He

    2017-07-01

    Full Text Available Freshwater resources in the North China Plain (NCP are near depletion due to the unceasing overexploitation of deep groundwater, by far the most significant source of freshwater in the region. To deal with the deepening freshwater crisis, brackish water (rich but largely unused water in agriculture is increasingly being used in irrigation in the region. However, inappropriate irrigation with brackish water could lead to soil salinization and cropland degradation. To evaluate such negative impacts, the HYDRUS-1D model was used to simulate soil salt transport and accumulation under 15 years of irrigation with brackish water. The irrigation scenarios included brackish water irrigation during the wintering and jointing stages of winter wheat and then freshwater irrigation just before the sowing of summer maize. Freshwater irrigation was done to leach out soil salts, which is particularly vital in dry years. For the littoral region of the plain, HYDRUS-ID was used to simulate the irrigated cropping system stated above for a total period of 15 years. The results showed that it was feasible to use brackish water twice in one year, provided freshwater irrigation was performed before sowing summer maize. Freshwater irrigation, in conjunction with precipitation, leached out soil salts from the 100 cm root-zone depth. The maximum salt accumulation was in the 160–220 cm soil layer, which ensured that root-zone soil was free of restrictive salinity for crop growth. Precipitation was a critical determinant of the rate and depth leaching of soil salt. Heavy rainfall (>100 mm caused significant leaching of soluble salts in the 0–200 cm soil profile. Salt concentration under brackish water irrigation had no significant effect on the variations in the trend of soil salt transport in the soil profile. The variations of soil salinity were mainly affected by hydrological year type, for which the buried depth of soil salt was higher in wet years than in dry years

  16. Interactions of microbicide nanoparticles with a simulated vaginal fluid.

    Science.gov (United States)

    das Neves, José; Rocha, Cristina M R; Gonçalves, Maria Pilar; Carrier, Rebecca L; Amiji, Mansoor; Bahia, Maria Fernanda; Sarmento, Bruno

    2012-11-05

    The interaction with cervicovaginal mucus presents the potential to impact the performance of drug nanocarriers. These systems must migrate through this biological fluid in order to deliver their drug payload to the underlying mucosal surface. We studied the ability of dapivirine-loaded polycaprolactone (PCL)-based nanoparticles (NPs) to interact with a simulated vaginal fluid (SVF) incorporating mucin. Different surface modifiers were used to produce NPs with either negative (poloxamer 338 NF and sodium lauryl sulfate) or positive (cetyltrimethylammonium bromide) surface charge. Studies were performed using the mucin particle method, rheological measurements, and real-time multiple particle tracking. Results showed that SVF presented rheological properties similar to those of human cervicovaginal mucus. Analysis of NP transport indicated mild interactions with mucin and low adhesive potential. In general, negatively charged NPs underwent subdiffusive transport in SVF, i.e., hindered as compared to their diffusion in water, but faster than for positively charged NPs. These differences were increased when the pH of SVF was changed from 4.2 to 7.0. Diffusivity was 50- and 172-fold lower in SVF at pH 4.2 than in water for negatively charged and positively charged NPs, respectively. At pH 7.0, this decrease was around 20- and 385-fold, respectively. The estimated times required to cross a layer of SVF were equal to or lower than 1.7 h for negatively charged NPs, while for positively charged NPs these values were equal to or higher than 7 h. Overall, our results suggest that negatively charged PCL NPs may be suitable to be used as carriers in order to deliver dapivirine and potentially other antiretroviral drugs to the cervicovaginal mucosal lining. Also, they further reinforce the importance in characterizing the interactions of nanosystems with mucus fluids or surrogates when considering mucosal drug delivery.

  17. Simulations of GCR interactions within planetary bodies using GEANT4

    Science.gov (United States)

    Mesick, K.; Feldman, W. C.; Stonehill, L. C.; Coupland, D. D. S.

    2017-12-01

    On planetary bodies with little to no atmosphere, Galactic Cosmic Rays (GCRs) can hit the body and produce neutrons primarily through nuclear spallation within the top few meters of the surfaces. These neutrons undergo further nuclear interactions with elements near the planetary surface and some will escape the surface and can be detected by landed or orbiting neutron radiation detector instruments. The neutron leakage signal at fast neutron energies provides a measure of average atomic mass of the near-surface material and in the epithermal and thermal energy ranges is highly sensitive to the presence of hydrogen. Gamma-rays can also escape the surface, produced at characteristic energies depending on surface composition, and can be detected by gamma-ray instruments. The intra-nuclear cascade (INC) that occurs when high-energy GCRs interact with elements within a planetary surface to produce the leakage neutron and gamma-ray signals is highly complex, and therefore Monte Carlo based radiation transport simulations are commonly used for predicting and interpreting measurements from planetary neutron and gamma-ray spectroscopy instruments. In the past, the simulation code that has been widely used for this type of analysis is MCNPX [1], which was benchmarked against data from the Lunar Neutron Probe Experiment (LPNE) on Apollo 17 [2]. In this work, we consider the validity of the radiation transport code GEANT4 [3], another widely used but open-source code, by benchmarking simulated predictions of the LPNE experiment to the Apollo 17 data. We consider the impact of different physics model options on the results, and show which models best describe the INC based on agreement with the Apollo 17 data. The success of this validation then gives us confidence in using GEANT4 to simulate GCR-induced neutron leakage signals on Mars in relevance to a re-analysis of Mars Odyssey Neutron Spectrometer data. References [1] D.B. Pelowitz, Los Alamos National Laboratory, LA-CP-05

  18. Beam equipment electromagnetic interaction in accelerators: simulation and experimental benchmarking

    CERN Document Server

    Passarelli, Andrea; Vaccaro, Vittorio Giorgio; Massa, Rita; Masullo, Maria Rosaria

    One of the most significant technological problems to achieve the nominal performances in the Large Hadron Collider (LHC) concerns the system of collimation of particle beams. The use of collimators crystals, exploiting the channeling effect on extracted beam, has been experimentally demonstrated. The first part of this thesis is about the optimization of UA9 goniometer at CERN, this device used for beam collimation will replace a part of the vacuum chamber. The optimization process, however, requires the calculation of the coupling impedance between the circulating beam and this structure in order to define the threshold of admissible intensity to do not trigger instability processes. Simulations have been performed with electromagnetic codes to evaluate the coupling impedance and to assess the beam-structure interaction. The results clearly showed that the most concerned resonance frequencies are due solely to the open cavity to the compartment of the motors and position sensors considering the crystal in o...

  19. Software Design for Interactive Graphic Radiation Treatment Simulation Systems*

    Science.gov (United States)

    Kalet, Ira J.; Sweeney, Christine; Jacky, Jonathan

    1990-01-01

    We examine issues in the design of interactive computer graphic simulation programs for radiation treatment planning (RTP), as well as expert system programs that automate parts of the RTP process, in light of ten years of experience at designing, building and using such programs. An experiment in object-oriented design using standard Pascal shows that while some advantage is gained from the design, it is still difficult to achieve modularity and to integrate expert system components. A new design based on the Common LISP Object System (CLOS) is described. This series of designs for RTP software shows that this application benefits in specific ways from object-oriented design methods and appropriate languages and tools.

  20. Assessing the impacts of climate change on winter crop production in Uruguay and Argentina using crop simulation models

    Energy Technology Data Exchange (ETDEWEB)

    Baethgen, W.E. [International Fertilizer Development Center, Muscle Shoals, AL (United States); Magrin, G.O. [Inst. Nacional de Tecnologia Agropecuaria Castelar, Buenos Aires (Argentina). Inst. de Clima y Agua

    1995-12-31

    Enhanced greenhouse effect caused by the increase in atmospheric concentration of CO{sub 2} and other trace gases could lead to higher global surface temperature and altered hydrological cycles. Most possible climate change scenarios include higher atmospheric CO{sub 2} concentrations, higher temperatures, and changes in precipitation. Three global climate models (GCMs) were applied to generate climate change scenarios for the Pampas region in southern South America. The generated scenarios were then used with crop simulation models to study the possible impact of climate change on wheat (Triticum aestivum L.) and barley (Hordeum vulgare L.) production in the Pampas. The authors evaluated the impact of possible climate change scenarios on wheat and barley production in Uruguay for a wide range of soil and crop management strategies including planting dates, cultivar types, fertilizer management, and tillage practices. They also studied the impact of climate change on wheat production across two transects of the Pampas: north to south transect with decreasing temperature, and east to west transect with decreasing precipitation. Finally, sensitivity analyses were conducted for both, the Uruguayan site and the transects, by increasing daily maximum and minimum temperature by 0, 2, and 4 C, and changing the precipitation by {minus}20, 0, and +20%.

  1. Hot interstellar tunnels. I. Simulation of interacting supernova remnants

    International Nuclear Information System (INIS)

    Smith, B.W.

    1977-01-01

    Reexamining a suggestion of Cox and Smith, we find that intersecting supernova remnants can indeed generate and maintain hot interstellar regions with napproximately-less-than10 -2 cm -3 and Tapprox.10 6 K. These regions are likely to occupy at least 30% of the volume of a spiral arm near the midplane of the gaseous disk if the local supernova rate there is greater than 1.5 x 10 -7 Myr -1 pc -3 . Their presence in the interstellar medium is supported by observations of the soft X-ray background. The theory required to build a numerical simulation of interacting supernova remnants is developed. The hot cavities within a population of remnants will become connected for a variety of assumed conditions in the outer shells of old remnants. Extensive hot cavity regions or tunnels are built and enlarged by supernovae occurring in relatively dense gas which produce connections, but tunnels are kept hot primarily by supernovae occurring within the tunnels. The latter supernovae initiate fast shock waves which apparently reheat tunnels faster than they are destroyed by thermal conduction in a galactic magnetic field or by radiative cooling. However, the dispersal of these rejuvenating shocks over a wide volume is inhibited by motions of cooler interstellar gas in the interval between shocks. These motions disrupt the contiguity of the component cavities of a tunnel and may cause its death.The Monte Carlo simulations indicate that a quasi-equilibrium is reached within 10 7 years of the first supernova in a spiral arm. This equilibrium is characterized by a constant average filling fraction for cavities in the interstellar volume. Aspects of the equilibrium are discussed for a range of supernova rates. Two predictions of Cox and Smith are not confirmed within this range: critical growth of hot regions to encompass the entire medium, and the efficient quenching of a remnant's expansion by interaction with other cavities

  2. Interactive Media and Simulation Tools for Technical Training

    Science.gov (United States)

    Gramoll, Kurt

    1997-01-01

    Over the last several years, integration of multiple media sources into a single information system has been rapidly developing. It has been found that when sound, graphics, text, animations, and simulations are skillfully integrated, the sum of the parts exceeds the individual parts for effective learning. In addition, simulations can be used to design and understand complex engineering processes. With the recent introduction of many high-level authoring, animation, modeling, and rendering programs for personal computers, significant multimedia programs can be developed by practicing engineers, scientists and even managers for both training and education. However, even with these new tools, a considerable amount of time is required to produce an interactive multimedia program. The development of both CD-ROM and Web-based programs are discussed in addition to the use of technically oriented animations. Also examined are various multimedia development tools and how they are used to develop effective engineering education courseware. Demonstrations of actual programs in engineering mechanics are shown.

  3. Enhancing food engineering education with interactive web-based simulations

    Directory of Open Access Journals (Sweden)

    Alexandros Koulouris

    2015-04-01

    Full Text Available In the traditional deductive approach in teaching any engineering topic, teachers would first expose students to the derivation of the equations that govern the behavior of a physical system and then demonstrate the use of equations through a limited number of textbook examples. This methodology, however, is rarely adequate to unmask the cause-effect and quantitative relationships between the system variables that the equations embody. Web-based simulation, which is the integration of simulation and internet technologies, has the potential to enhance the learning experience by offering an interactive and easily accessible platform for quick and effortless experimentation with physical phenomena.This paper presents the design and development of a web-based platform for teaching basic food engineering phenomena to food technology students. The platform contains a variety of modules (“virtual experiments” covering the topics of mass and energy balances, fluid mechanics and heat transfer. In this paper, the design and development of three modules for mass balances and heat transfer is presented. Each webpage representing an educational module has the following features: visualization of the studied phenomenon through graphs, charts or videos, computation through a mathematical model and experimentation.  The student is allowed to edit key parameters of the phenomenon and observe the effect of these changes on the outputs. Experimentation can be done in a free or guided fashion with a set of prefabricated examples that students can run and self-test their knowledge by answering multiple-choice questions.

  4. Global simulation of interactions between groundwater and terrestrial ecosystems

    Science.gov (United States)

    Braakhekke, M. C.; Rebel, K.; Dekker, S. C.; Smith, B.; Van Beek, L. P.; Sutanudjaja, E.; van Kampenhout, L.; Wassen, M. J.

    2016-12-01

    In many places in the world ecosystems are influenced by the presence of a shallow groundwater table. In these regions upward water flux due to capillary rise increases soil moisture availability in the root zone, which has strong positive effect on evapotranspiration. Additionally it has important consequences for vegetation dynamics and fluxes of carbon and nitrogen. Under water limited conditions shallow groundwater stimulates vegetation productivity, and soil organic matter decomposition while under saturated conditions groundwater may have a negative effect on these processes due to lack of oxygen. Furthermore, since plant species differ with respect to their root distribution, preference for moisture conditions, and resistance to oxygen stress, shallow groundwater also influences vegetation type. Finally, processes such as denitrification and methane production occur under strictly anaerobic conditions and are thus strongly influenced by moisture availability. Most global hydrological models and several land surface models simulate groundwater table dynamics and their effects on land surface processes. However, these models typically have relatively simplistic representation of vegetation and do not consider changes in vegetation type and structure and are therefore less suitable to represent effects of groundwater on biogeochemical fluxes. Dynamic global vegetation models (DGVMs), describe land surface from an ecological perspective, combining detailed description of vegetation dynamics and structure and biogeochemical processes. These models are thus more appropriate to simulate the ecological and biogeochemical effects of groundwater interactions. However, currently virtually all DGVMs ignore these effects, assuming that water tables are too deep to affect soil moisture in the root zone. We have implemented a tight coupling between the dynamic global ecosystem model LPJ-GUESS and the global hydrological model PCR-GLOBWB. Using this coupled model we aim to

  5. Simulating market dynamics: interactions between consumer psychology and social networks.

    Science.gov (United States)

    Janssen, Marco A; Jager, Wander

    2003-01-01

    Markets can show different types of dynamics, from quiet markets dominated by one or a few products, to markets with continual penetration of new and reintroduced products. In a previous article we explored the dynamics of markets from a psychological perspective using a multi-agent simulation model. The main results indicated that the behavioral rules dominating the artificial consumer's decision making determine the resulting market dynamics, such as fashions, lock-in, and unstable renewal. Results also show the importance of psychological variables like social networks, preferences, and the need for identity to explain the dynamics of markets. In this article we extend this work in two directions. First, we will focus on a more systematic investigation of the effects of different network structures. The previous article was based on Watts and Strogatz's approach, which describes the small-world and clustering characteristics in networks. More recent research demonstrated that many large networks display a scale-free power-law distribution for node connectivity. In terms of market dynamics this may imply that a small proportion of consumers may have an exceptional influence on the consumptive behavior of others (hubs, or early adapters). We show that market dynamics is a self-organized property depending on the interaction between the agents' decision-making process (heuristics), the product characteristics (degree of satisfaction of unit of consumption, visibility), and the structure of interactions between agents (size of network and hubs in a social network).

  6. Numerical Simulation of Wind Turbine Blade-Tower Interaction

    Institute of Scientific and Technical Information of China (English)

    Qiang Wang; Hu Zhou; Decheng Wan

    2012-01-01

    Numerical simulations of wind turbine blade-tower interaction by using the open source OpenFOAM tools coupled with arbitrary mesh interface (AMI) method were presented.The governing equations were the unsteady Reynolds-averaged Navier-Stokes (PANS) which were solved by the pimpleDyMFoam solver,and the AMI method was employed to handle mesh movements.The National Renewable Energy Laboratory (NREL) phase Ⅵ wind turbine in upwind configuration was selected for numerical tests with different incoming wind speeds (5,10,15,and 25 m/s) at a fixed blade pitch and constant rotational speed.Detailed numerical results of vortex structure,time histories of thrust,and pressure distribution on the blade and tower were presented.The findings show that the wind turbine tower has little effect on the whole aerodynamic performance of an upwind wind turbine,while the rotating rotor will induce an obvious cyclic drop in the front pressure of the tower.Also,strong interaction of blade tip vortices with separation from the tower was observed.

  7. Simulation of the dynamics of laser-cluster interaction

    International Nuclear Information System (INIS)

    Deiss, C.

    2009-01-01

    Ranging in size from a few atoms to several million atoms, clusters form a link between gases and solids. When irradiating clusters with intense femtosecond laser pulses, the production of energetic and highly charged ions, hot electrons, and extreme UV and X-ray photons, gives evidence of a very efficient energy conversion. The size of the system and the multitude of mechanisms at play provide a considerable challenge for the theoretical treatment of the interaction. In this thesis, we have developed a Classical Trajectory Monte Carlo simulation that gives insight into the particle dynamics during the interaction of laser pulses with large argon clusters (with more than 10000 atoms per cluster). Elastic electron-ion scattering, electron-electron scattering, electron-impact ionization and excitation, as well as three-body recombination and Auger decay are included via stochastic events. In a strongly simplified picture, the dynamics of the laser-cluster interaction can be summarized as follows: the intense laser field ionizes the cluster atoms and drives the population of quasi-free electrons. In collision events, further free electrons and high ionic charge states are created. As some electrons leave the cluster, the ions feel a net positive charge, and the cluster ultimately disintegrates in a Coulomb explosion. Even at moderate laser intensities (approx. 10 15 W/cm 2 ), impact ionization produces inner-shell vacancies in the cluster ions that decay by emitting characteristic X-ray radiation. The small population of fast electrons responsible for these ionization events is produced near the cluster poles, where the combination of polarization and charging of the cluster leads to strongly enhanced field strengths. We achieve a good agreement over large parameter ranges between the simulation and X-ray spectroscopy experiments. We also investigate the dependence of X-ray emission on laser intensity, pulse duration and cluster size. We find that in order to

  8. The Year Without a Ski Season: An Analysis of the Winter of 2015 for Three Ski Resorts in Western Canada Using Historical and Simulation Model Forecasted Climate Data

    Science.gov (United States)

    Pidwirny, M. J.; Goode, J. D.; Pedersen, S.

    2015-12-01

    The winter of 2015 will go down as "the year without a ski season" for many ski resorts located close to the west coast of Canada and the USA. During this winter season, a large area of the eastern North Pacific Ocean had extremely high sea surface temperatures. These high sea surface temperatures influenced weather patterns on the west coast of North America producing very mild temperatures inland. Further, in alpine environments precipitation that normally arrives in the form of snow instead fell as rain. This research examines the climate characteristics of the winter of 2015 in greater detail for three ski resorts in British Columbia, Canada: Mount Washington, Cypress Mountain and Hemlock Valley. For these resorts, historical (1901 to 2013) and IPCC AR5 climate model forecasted climate data (RCP8.5 for 2025, 2055, and 2085) was generated for the variable winter degree days climate database ClimateBC. A value for winter degree days climate data at nearby meteorological stations for comparative analysis. For all three resorts, the winter of 2015 proved to be warmer than any individual year in the period 1901 to 2013. Interpolations involving the multi-model ensemble forecast means suggest that the climate associated with winter of 2015 will become the average normal for these resorts in only 35 to 45 years under the RCP8.5 emission scenario.

  9. Winter wheat response to irrigation, nitrogen fertilization, and cold hazards in the Community Land Model 5

    Science.gov (United States)

    Lu, Y.

    2017-12-01

    Winter wheat is a staple crop for global food security, and is the dominant vegetation cover for a significant fraction of earth's croplands. As such, it plays an important role in soil carbon balance, and land-atmosphere interactions in these key regions. Accurate simulation of winter wheat growth is not only crucial for future yield prediction under changing climate, but also for understanding the energy and water cycles for winter wheat dominated regions. A winter wheat growth model has been developed in the Community Land Model 4.5 (CLM4.5), but its responses to irrigation and nitrogen fertilization have not been validated. In this study, I will validate winter wheat growth response to irrigation and nitrogen fertilization at five winter wheat field sites (TXLU, KSMA, NESA, NDMA, and ABLE) in North America, which were originally designed to understand winter wheat response to nitrogen fertilization and water treatments (4 nitrogen levels and 3 irrigation regimes). I also plan to further update the linkages between winter wheat yield and cold hazards. The previous cold damage function only indirectly affects yield through reduction on leaf area index (LAI) and hence photosynthesis, such approach could sometimes produce an unwanted higher yield when the reduced LAI saved more nutrient in the grain fill stage.

  10. Cloud Service for Interactive Simulation of Interregional Trade

    Directory of Open Access Journals (Sweden)

    A. S. Velichko

    2016-01-01

    Full Text Available The paper describes a mathematical model of trade flows between the territories of a region or a country in a transport network having one or more different types of marine or ground transportation. We use the approach of modeling complex communication systems to determine the most probable values of flows in case of incomplete information about the system. Transport costs between the territories are modeled within the framework of the gravity model. The payment for transportation depends on the distance between regions, the distance is estimated as the shortest way length in a given transport network or geographical distance. The mathematical formulation of the problem belongs to the class of convex mathematical programming problems and assumes the numerical solution of nonlinear optimization problem with linear constraints. Based on the model, the software is implemented as a cloud service on heterogeneous computing architectures: the simulation module is made on a highperformance server platform, management and visualization modules are produced with IACPaaS cloud platform. Communication between the platforms is established via asynchronous http-queries. For information exchange between the modules the declarative model with JSON format is developed and implemented for the objects considered in the mathematical model which are products, areas and communications. Visualization module allows to present graphically the original and the resulting matrix data and to modify the input parameters of the model interactively. The paper demonstrates the use of software for the simulation of inter-regional freight traffic of the Russian Far East region based on input data provided by open statistics sources.

  11. Analysis of pellet cladding mechanical interaction using computational simulation

    Energy Technology Data Exchange (ETDEWEB)

    Berretta, José R.; Suman, Ricardo B.; Faria, Danilo P.; Rodi, Paulo A., E-mail: jose.berretta@marinha.mil.br [Centro Tecnológico da Marinha em São Paulo (CTMSP), São Paulo, SP (Brazil); Giovedi, Claudia, E-mail: claudia.giovedi@labrisco.usp.br [Universidade de Sao Paulo (LabRisco/USP), São Paulo, SP (Brazil). Laboratório de Análise, Avaliação e Gerenciamento de Riscos

    2017-07-01

    During the operation of Pressurized Water Reactors (PWR), specifically under power transients, the fuel pellet experiences many phenomena, such as swelling and thermal expansion. These dimensional changes in the fuel pellet can enable occurrence of contact it and the cladding along the fuel rod. Thus, pellet cladding mechanical interaction (PCMI), due this contact, induces stress increase at the contact points during a period, until the accommodation of the cladding to the stress increases. This accommodation occurs by means of the cladding strain, which can produce failure, if the fuel rod deformation is permanent or the burst limit of the cladding is reached. Therefore, the mechanical behavior of the cladding during the occurrence of PCMI under power transients shall be investigated during the fuel rod design. Considering the Accident Tolerant Fuel program which aims to develop new materials to be used as cladding in PWR, one important design condition to be evaluated is the cladding behavior under PCMI. The purpose of this paper is to analyze the effects of the PCMI on a typical PWR fuel rod geometry with stainless steel cladding under normal power transients using computational simulation (ANSYS code). The PCMI was analyzed considering four geometric situations at the region of interaction between pellet and cladding. The first case, called “perfect fuel model” was used as reference for comparison. In the second case, it was considered the occurrence of a pellet crack with the loss of a chip. The goal for the next two cases was that a pellet chip was positioned into the gap of pellet-cladding, in the situations described in the first two cases. (author)

  12. Fundamental experiment on simulated molten core/concrete interaction

    International Nuclear Information System (INIS)

    Toda, S.; Katsumura, Y.

    1994-01-01

    If a complete and prolonged failure of coolant flow were to occur in a LWR or FBR, fission product decay heat would cause the fuel to overheat. If no available action to cool the fuel were taken, it would eventually melt. Ibis could lead to slumping of the molten core material and to the failure of the reactor pressure vessel and deposition of these materials into the concrete reactor cavity. Consequently, the molten core could melt and decompose the concrete. Vigorous agitation of the molten core pool by concrete decomposition gases is expected to enhance the convective heat transfer process. Besides the decomposition gases, melting concrete (slag) generated under the molten core pool will be buoyed up, and will also affect the downward heat transfer. Though, in this way, the heat transfer process across the interface is complicated by the slag and the gases evolved from the decomposed concrete, it is very important to make its process clear for the safety evaluation of nuclear reactors. Therefore, in this study, fundamental experiments were performed using simulated materials to observe the behaviors of the hot pool, slag and gases at the interface. Moreover, from the experimental observation, a correlation without empirical constants was proposed to calculate the interface heat transfer. The heat transfer across the interface would depend on thermo-physical interactions between the pool, slag and concrete which are changed by their thermal properties and interface temperature and so on. For example, the molten concrete is miscible in molten oxidic core debris, but is immiscible in metallic core debris. If a contact temperature between the molten core pool and the concrete falls below the solidus of the pool, solidification of the pool will occur. In this study, the case of immiscible slag in the pool is treated and solidification of the pool does not occur. Thus, water, paraffin and air were selected as the simulated molten core pool, concrete, and decomposition

  13. Timing Interactions in Social Simulations: The Voter Model

    Science.gov (United States)

    Fernández-Gracia, Juan; Eguíluz, Víctor M.; Miguel, Maxi San

    The recent availability of huge high resolution datasets on human activities has revealed the heavy-tailed nature of the interevent time distributions. In social simulations of interacting agents the standard approach has been to use Poisson processes to update the state of the agents, which gives rise to very homogeneous activity patterns with a well defined characteristic interevent time. As a paradigmatic opinion model we investigate the voter model and review the standard update rules and propose two new update rules which are able to account for heterogeneous activity patterns. For the new update rules each node gets updated with a probability that depends on the time since the last event of the node, where an event can be an update attempt (exogenous update) or a change of state (endogenous update). We find that both update rules can give rise to power law interevent time distributions, although the endogenous one more robustly. Apart from that for the exogenous update rule and the standard update rules the voter model does not reach consensus in the infinite size limit, while for the endogenous update there exist a coarsening process that drives the system toward consensus configurations.

  14. Numerical Simulation of Tower Rotor Interaction for Downwind Wind Turbine

    Directory of Open Access Journals (Sweden)

    Isam Janajreh

    2010-01-01

    Full Text Available Downwind wind turbines have lower upwind rotor misalignment, and thus lower turning moment and self-steered advantage over the upwind configuration. In this paper, numerical simulation to the downwind turbine is conducted to investigate the interaction between the tower and the blade during the intrinsic passage of the rotor in the wake of the tower. The moving rotor has been accounted for via ALE formulation of the incompressible, unsteady, turbulent Navier-Stokes equations. The localized CP, CL, and CD are computed and compared to undisturbed flow evaluated by Panel method. The time history of the CP, aerodynamic forces (CL and CD, as well as moments were evaluated for three cross-sectional tower; asymmetrical airfoil (NACA0012 having four times the rotor's chord length, and two circular cross-sections having four and two chords lengths of the rotor's chord. 5%, 17%, and 57% reductions of the aerodynamic lift forces during the blade passage in the wake of the symmetrical airfoil tower, small circular cross-section tower and large circular cross-section tower were observed, respectively. The pronounced reduction, however, is confined to a short time/distance of three rotor chords. A net forward impulsive force is also observed on the tower due to the high speed rotor motion.

  15. Implementation of interactive virtual simulation of physical systems

    International Nuclear Information System (INIS)

    Sanchez, H; Escobar, J J; Gonzalez, J D; Beltran, J

    2014-01-01

    Considering the limited availability of laboratories for physics teaching and the difficulties this causes in the learning of school students in Santa Marta Colombia, we have developed software in order to generate greater student interaction with the phenomena physical and improve their understanding. Thereby, this system has been proposed in an architecture Model/View- View- Model (MVVM), sharing the benefits of MVC. Basically, this pattern consists of 3 parts: The Model, that is responsible for business logic related. The View, which is the part with which we are most familiar and the user sees. Its role is to display data to the user and allowing manipulation of the data of the application. The ViewModel, which is the middle part of the Model and the View (analogous to the Controller in the MVC pattern), as well as being responsible for implementing the behavior of the view to respond to user actions and expose data model in a way that is easy to use links to data in the view. .NET Framework 4.0 and editing package Silverlight 4 and 5 are the main requirements needed for the deployment of physical simulations that are hosted in the web application and a web browser (Internet Explorer, Mozilla Firefox or Chrome). The implementation of this innovative application in educational institutions has shown that students improved their contextualization of physical phenomena

  16. Straw export in continuous winter wheat and the ability of oil radish catch crops and early sowing of wheat to offset soil C and N losses: A simulation study

    DEFF Research Database (Denmark)

    Peltre, Clément; Nielsen, M; Christensen, Bent Tolstrup

    2016-01-01

    The export of winter wheat straw for bioenergy may reduce soil C stocks and affect N losses. Establishing fast-growing catch crops between successive wheat crops could potentially offset some of the C and N losses. Another option is to sow wheat earlier, increasing biomass production during...... the autumn. The effects of straw export, oil radish catch crop and early sowing of wheat on soil C storage, N leaching losses and N2O emissions were simulated by applying the Daisy model to winter wheat grown continuously for a period of 100 years on a sandy loam soil in a Danish climate. The simulations....... Inclusion of the oil radish catch crop could offset this loss by 2–3 percentage points. Earlier sowing of wheat increased straw production by 18% and reduced loss of soil C by 3–5 percentage points compared to normal sowing time with full straw export. Catch crops and early sowing also reduced N...

  17. Low-high latitude interaction forcing on the evolution of the 400 kyr cycle in East Asian winter monsoon records during the last 2.8 Myr

    Science.gov (United States)

    Li, Dawei; Zhao, Meixun; Tian, Jun

    2017-09-01

    Variability of the East Asian winter monsoon (EAWM), stronger during glacials and weaker during interglacials, has been tightly linked to the wax and wane of the Northern Hemisphere ice sheets (NHIS) via the Siberian High over the last 2.8 million years (Myr). However, the long eccentricity cycle (ca. 400 kyr) in the EAWM record from the late Pliocene to early-Pleistocene (2.8-1.2 Ma) could not be linked to NHIS changes, which lacked the long eccentricity cycle in the Pleistocene. Here, we present the first low latitude EAWM record of the last 2.8 Myr using surface and subsurface temperature difference from the northern South China Sea to evaluate interactions between tropical ocean and EAWM changes. The results show that the EAWM variability displayed significant 400 kyr cycle between 2.8 Ma and 1.2 Ma, with weak (strong) EAWM during high (low) earth orbital eccentricity state. A super El Niño-Southern Oscillation (ENSO) proxy record, calculated using west-east equatorial Pacific sea surface temperature differences, revealed 400 kyr cycles throughout the last 2.8 Myr with warm phase during high eccentricity state. Thus, we propose that super ENSO mean state strongly modulated the EAWM strength through remote forcing to generate the 400 kyr cycle between 2.8 Ma and 1.2 Ma, while low NHIS volume was not sufficient to dominate the EAWM variation as it did over the last 0.9 Myr with 100 kyr cycles in dominance.

  18. Evaluation of the Community Multiscale Air Quality Model for Simulating Winter Ozone Formation in the Uinta Basin with Intensive Oil and Gas Production

    Science.gov (United States)

    Matichuk, R.; Tonnesen, G.; Luecken, D.; Roselle, S. J.; Napelenok, S. L.; Baker, K. R.; Gilliam, R. C.; Misenis, C.; Murphy, B.; Schwede, D. B.

    2015-12-01

    The western United States is an important source of domestic energy resources. One of the primary environmental impacts associated with oil and natural gas production is related to air emission releases of a number of air pollutants. Some of these pollutants are important precursors to the formation of ground-level ozone. To better understand ozone impacts and other air quality issues, photochemical air quality models are used to simulate the changes in pollutant concentrations in the atmosphere on local, regional, and national spatial scales. These models are important for air quality management because they assist in identifying source contributions to air quality problems and designing effective strategies to reduce harmful air pollutants. The success of predicting oil and natural gas air quality impacts depends on the accuracy of the input information, including emissions inventories, meteorological information, and boundary conditions. The treatment of chemical and physical processes within these models is equally important. However, given the limited amount of data collected for oil and natural gas production emissions in the past and the complex terrain and meteorological conditions in western states, the ability of these models to accurately predict pollution concentrations from these sources is uncertain. Therefore, this presentation will focus on understanding the Community Multiscale Air Quality (CMAQ) model's ability to predict air quality impacts associated with oil and natural gas production and its sensitivity to input uncertainties. The results will focus on winter ozone issues in the Uinta Basin, Utah and identify the factors contributing to model performance issues. The results of this study will help support future air quality model development, policy and regulatory decisions for the oil and gas sector.

  19. Hybrid Simulation of the Interaction of Europa's Atmosphere with the Jovian Plasma: Multiprocessor Simulations

    Science.gov (United States)

    Dols, V. J.; Delamere, P. A.; Bagenal, F.; Cassidy, T. A.; Crary, F. J.

    2014-12-01

    We model the interaction of Europa's tenuous atmosphere with the plasma of Jupiter's torus with an improved version of our hybrid plasma code. In a hybrid plasma code, the ions are treated as kinetic Macro-particles moving under the Lorentz force and the electrons as a fluid leading to a generalized formulation of Ohm's law. In this version, the spatial simulation domain is decomposed in 2 directions and is non-uniform in the plasma convection direction. The code is run on a multi-processor supercomputer that offers 16416 cores and 2GB Ram per core. This new version allows us to tap into the large memory of the supercomputer and simulate the full interaction volume (Reuropa=1561km) with a high spatial resolution (50km). Compared to Io, Europa's atmosphere is about 100 times more tenuous, the ambient magnetic field is weaker and the density of incident plasma is lower. Consequently, the electrodynamic interaction is also weaker and substantial fluxes of thermal torus ions might reach and sputter the icy surface. Molecular O2 is the dominant atmospheric product of this surface sputtering. Observations of oxygen UV emissions (specifically the ratio of OI 1356A / 1304A emissions) are roughly consistent with an atmosphere that is composed predominantely of O2 with a small amount of atomic O. Galileo observations along flybys close to Europa have revealed the existence of induced currents in a conducting ocean under the icy crust. They also showed that, from flyby to flyby, the plasma interaction is very variable. Asymmetries of the plasma density and temperature in the wake of Europa were also observed and still elude a clear explanation. Galileo mag data also detected ion cyclotron waves, which is an indication of heavy ion pickup close to the moon. We prescribe an O2 atmosphere with a vertical density column consistent with UV observations and model the plasma properties along several Galileo flybys of the moon. We compare our results with the magnetometer

  20. Controlling simulations of human-artifact interaction with scenario bundles

    NARCIS (Netherlands)

    Van der Vegte, W.F.; Rusák, Z.

    2008-01-01

    We introduce a methodology for modeling and simulating fully virtual human-artifact systems, aiming to resolve two issues in virtual prototyping: (i) integration of distinct modeling and simulation approaches, and (ii) extending the deployability of simulations towards conceptual design. We are

  1. Fluid, solid and fluid-structure interaction simulations on patient-based abdominal aortic aneurysm models.

    Science.gov (United States)

    Kelly, Sinead; O'Rourke, Malachy

    2012-04-01

    This article describes the use of fluid, solid and fluid-structure interaction simulations on three patient-based abdominal aortic aneurysm geometries. All simulations were carried out using OpenFOAM, which uses the finite volume method to solve both fluid and solid equations. Initially a fluid-only simulation was carried out on a single patient-based geometry and results from this simulation were compared with experimental results. There was good qualitative and quantitative agreement between the experimental and numerical results, suggesting that OpenFOAM is capable of predicting the main features of unsteady flow through a complex patient-based abdominal aortic aneurysm geometry. The intraluminal thrombus and arterial wall were then included, and solid stress and fluid-structure interaction simulations were performed on this, and two other patient-based abdominal aortic aneurysm geometries. It was found that the solid stress simulations resulted in an under-estimation of the maximum stress by up to 5.9% when compared with the fluid-structure interaction simulations. In the fluid-structure interaction simulations, flow induced pressure within the aneurysm was found to be up to 4.8% higher than the value of peak systolic pressure imposed in the solid stress simulations, which is likely to be the cause of the variation in the stress results. In comparing the results from the initial fluid-only simulation with results from the fluid-structure interaction simulation on the same patient, it was found that wall shear stress values varied by up to 35% between the two simulation methods. It was concluded that solid stress simulations are adequate to predict the maximum stress in an aneurysm wall, while fluid-structure interaction simulations should be performed if accurate prediction of the fluid wall shear stress is necessary. Therefore, the decision to perform fluid-structure interaction simulations should be based on the particular variables of interest in a given

  2. Winter Weather Emergencies

    Science.gov (United States)

    Severe winter weather can lead to health and safety challenges. You may have to cope with Cold related health problems, including ... there are no guarantees of safety during winter weather emergencies, you can take actions to protect yourself. ...

  3. Winter maintenance performance measure.

    Science.gov (United States)

    2016-01-01

    The Winter Performance Index is a method of quantifying winter storm events and the DOTs response to them. : It is a valuable tool for evaluating the States maintenance practices, performing post-storm analysis, training : maintenance personnel...

  4. Winter weather demand considerations.

    Science.gov (United States)

    2015-04-01

    Winter weather has varied effects on travel behavior. Using 418 survey responses from the Northern Virginia : commuting area of Washington, D.C. and binary logit models, this study examines travel related changes under : different types of winter wea...

  5. Using interactive model simulations in co-design : An experiment in urban design

    NARCIS (Netherlands)

    Steen, M.G.D.; Arendsen, J.; Cremers, A.H.M.; Vries, A. de; Jong, J.M.G. de; Koning, N.M. de

    2013-01-01

    This paper presents an experiment in which people performed a co-design task in urban design, using a multi-user touch table application with or without interactive model simulations. We hypothesised that using the interactive model simulations would improve communication and co-operation between

  6. Simulation of Robot Kinematics Using Interactive Computer Graphics.

    Science.gov (United States)

    Leu, M. C.; Mahajan, R.

    1984-01-01

    Development of a robot simulation program based on geometric transformation softwares available in most computer graphics systems and program features are described. The program can be extended to simulate robots coordinating with external devices (such as tools, fixtures, conveyors) using geometric transformations to describe the…

  7. Analyzing Interaction Patterns to Verify a Simulation/Game Model

    Science.gov (United States)

    Myers, Rodney Dean

    2012-01-01

    In order for simulations and games to be effective for learning, instructional designers must verify that the underlying computational models being used have an appropriate degree of fidelity to the conceptual models of their real-world counterparts. A simulation/game that provides incorrect feedback is likely to promote misunderstanding and…

  8. Numerical simulation of the impact of reforestation on winter meteorology and environment in a semi-arid urban valley, Northwestern China

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Ye, E-mail: yyu@lzb.ac.cn [Clod and Arid Regions Environmental and Engineering Research Institute, Key Laboratory of Land Surface Process and Climate Change in Cold & Arid Regions, Chinese Academy of Sciences, Lanzhou 730000 (China); He, Jianjun, E-mail: 18766167147@163.com [Clod and Arid Regions Environmental and Engineering Research Institute, Key Laboratory of Land Surface Process and Climate Change in Cold & Arid Regions, Chinese Academy of Sciences, Lanzhou 730000 (China); College of Environmental Science & Engineering, Nankai University, Tianjin 300071 (China); Zhao, Suping [Clod and Arid Regions Environmental and Engineering Research Institute, Key Laboratory of Land Surface Process and Climate Change in Cold & Arid Regions, Chinese Academy of Sciences, Lanzhou 730000 (China); Liu, Na [Clod and Arid Regions Environmental and Engineering Research Institute, Key Laboratory of Land Surface Process and Climate Change in Cold & Arid Regions, Chinese Academy of Sciences, Lanzhou 730000 (China); Weather Modification Office, Qinghai Meteorological Bureau, Xining 810001 (China); Chen, Jinbei [Clod and Arid Regions Environmental and Engineering Research Institute, Key Laboratory of Land Surface Process and Climate Change in Cold & Arid Regions, Chinese Academy of Sciences, Lanzhou 730000 (China); Mao, Hongjun; Wu, Lin [College of Environmental Science & Engineering, Nankai University, Tianjin 300071 (China)

    2016-11-01

    Since 1999 Chinese government has made great effort to reforest the south and north mountains surrounding urban Lanzhou – a city located in a river valley, Northwestern China. Until 2009 obvious land use change occurred, with 69.2% of the reforested area been changed from grasslands, croplands, barren or sparsely vegetated land to closed shrublands and 20.6% from closed shrublands, grasslands, and croplands to forests. Reforestation changes land-surface properties, with possible impact on the evolution of atmospheric variables. To understand to what extent the local meteorology and environment could be affected by reforestation in winter, and through what processes, two sets of simulations were conducted using the Weather Research and Forecasting model (WRF) and the FLEXible PARTicle (FLEXPART) dispersion model for a control case with high-resolution remotely sensed land cover data for 2009 and a scenario assuming no reforestation since 1999. Results suggested that the changes in albedo, surface exchange coefficient and surface soil heat conductivity related to reforestation led to the changes in surface net radiation and surface energy partitioning, which in turn affected the meteorological fields and enhanced the mountain-valley wind circulation. Replacement of shrublands and grassland with forest in the south mountain through reforestation play a dominant role in the enhancement of mountain-valley wind circulation. Reforestation increased the amount of air exchanged between the valley and the outside during the day, with the largest hourly increase of 10% on calm weather days and a monthly mean hourly increase of 2% for the study period (Dec. 2009). Reforestation affected the spatial distribution of pollutants and slightly improved the urban air quality, especially in the eastern valley. Results from this study provide useful information for future urban air quality management and reforestation plan, and some experience for cities with similar situations in

  9. Numerical simulation of the impact of reforestation on winter meteorology and environment in a semi-arid urban valley, Northwestern China

    International Nuclear Information System (INIS)

    Yu, Ye; He, Jianjun; Zhao, Suping; Liu, Na; Chen, Jinbei; Mao, Hongjun; Wu, Lin

    2016-01-01

    Since 1999 Chinese government has made great effort to reforest the south and north mountains surrounding urban Lanzhou – a city located in a river valley, Northwestern China. Until 2009 obvious land use change occurred, with 69.2% of the reforested area been changed from grasslands, croplands, barren or sparsely vegetated land to closed shrublands and 20.6% from closed shrublands, grasslands, and croplands to forests. Reforestation changes land-surface properties, with possible impact on the evolution of atmospheric variables. To understand to what extent the local meteorology and environment could be affected by reforestation in winter, and through what processes, two sets of simulations were conducted using the Weather Research and Forecasting model (WRF) and the FLEXible PARTicle (FLEXPART) dispersion model for a control case with high-resolution remotely sensed land cover data for 2009 and a scenario assuming no reforestation since 1999. Results suggested that the changes in albedo, surface exchange coefficient and surface soil heat conductivity related to reforestation led to the changes in surface net radiation and surface energy partitioning, which in turn affected the meteorological fields and enhanced the mountain-valley wind circulation. Replacement of shrublands and grassland with forest in the south mountain through reforestation play a dominant role in the enhancement of mountain-valley wind circulation. Reforestation increased the amount of air exchanged between the valley and the outside during the day, with the largest hourly increase of 10% on calm weather days and a monthly mean hourly increase of 2% for the study period (Dec. 2009). Reforestation affected the spatial distribution of pollutants and slightly improved the urban air quality, especially in the eastern valley. Results from this study provide useful information for future urban air quality management and reforestation plan, and some experience for cities with similar situations in

  10. Simulation Architecture for Modelling Interaction Between User and Elbow-articulated Exoskeleton

    NARCIS (Netherlands)

    Kruif, B.J. de; Schmidhauser, E.; Stadler, K.S.; O'Sullivan, L.W.

    2017-01-01

    The aim of our work is to improve the existing user-exoskeleton models by introducing a simulation architecture that can simulate its dynamic interaction, thereby altering the initial motion of the user. A simulation architecture is developed that uses the musculoskeletal models from OpenSim, and

  11. An Interactive Teaching System for Bond Graph Modeling and Simulation in Bioengineering

    Science.gov (United States)

    Roman, Monica; Popescu, Dorin; Selisteanu, Dan

    2013-01-01

    The objective of the present work was to implement a teaching system useful in modeling and simulation of biotechnological processes. The interactive system is based on applications developed using 20-sim modeling and simulation software environment. A procedure for the simulation of bioprocesses modeled by bond graphs is proposed and simulators…

  12. Ion-surface interaction: simulation of plasma-wall interaction (ITER)

    International Nuclear Information System (INIS)

    Salou, Pierre

    2013-01-01

    The wall materials of magnetic confinement in fusion machines are exposed to an aggressive environment; the reactor blanket is bombarded with a high flux of particles extracted from the plasma, leading to the sputtering of surface material. This sputtering causes wall erosion as well as plasma contamination problems. In order to control fusion reactions in complex reactors, it is thus imperative to well understand the plasma-wall interactions. This work proposes the study of the sputtering of fusion relevant materials. We propose to simulate the charged particles influx by few keV single-charged ion beams. This study is based on the catcher method; to avoid any problem of pollution (especially in the case of carbon) we designed a new setup allowing an in situ Auger electron spectroscopy analysis. The results provide the evolution of the angular distribution of the sputtering yield as a function of the ion mass (from helium to xenon) and its energy (from 3 keV to 9 keV). (author) [fr

  13. Supporting hypothesis generation by learners exploring an interactive computer simulation

    NARCIS (Netherlands)

    van Joolingen, Wouter R.; de Jong, Ton

    1992-01-01

    Computer simulations provide environments enabling exploratory learning. Research has shown that these types of learning environments are promising applications of computer assisted learning but also that they introduce complex learning settings, involving a large number of learning processes. This

  14. Validation of AquaCrop Model for Simulation of Winter Wheat Yield and Water Use Efficiency under Simultaneous Salinity and Water Stress

    Directory of Open Access Journals (Sweden)

    M. Mohammadi

    2016-02-01

    simulation of soil salinity. In general, the model accuracy for simulation yield and WP was better than simulation of biomass. The d (index of agreement values were very close to one for both varieties, which means that simulated reduction in grain yield and biomass was similar to those of measured ones. In most cases the R2 values were about one, confirming a good correlation between simulated and measured values. The NRMSE values in most cases were lower than 10% which seems to be good. The CRM values were close to zero (under- and over-estimation were negligible. Based on higher WP under deficit irrigation treatments (e.g. I3 compared to full irrigation treatments (e.g. I1 and I2, it seems logical to adopt I3 treatment, especially in Birjand as a water-short region, assigning the remaining 25% to another piece of land. By such strategy, WP would be optimized at the regional scale. Conclusion: The AquaCrop was separately and simultaneously nested calibrated and validated for all salinity treatments. The model accuracy under simultaneous case was slightly lower than that for separate case. According to the results, if the model is well calibrated for minimum and maximum irrigation treatments (full irrigation and maximum deficit irrigation, it could simulate grain yield for any other irrigation treatment in between these two limits. Adopting this approach may reduce the cost of field studies for calibrating the model, since only two irrigation treatments should be conducted in the field. AquaCrop model can be a valuable tool for modelling winter wheat grain yield, WP and biomass. The simplicity of AquaCrop, as it is less data dependent, made it to be user-friendly. Nevertheless, the performance of the model has to be evaluated, validated and fine-tuned under a wider range of conditions and crops. Keywords: Biomass, Plant modeling, Sensitivity analysis

  15. Stochastic annealing simulations of defect interactions among subcascades

    Energy Technology Data Exchange (ETDEWEB)

    Heinisch, H.L. [Pacific Northwest National Lab., Richland, WA (United States); Singh, B.N.

    1997-04-01

    The effects of the subcascade structure of high energy cascades on the temperature dependencies of annihilation, clustering and free defect production are investigated. The subcascade structure is simulated by closely spaced groups of lower energy MD cascades. The simulation results illustrate the strong influence of the defect configuration existing in the primary damage state on subsequent intracascade evolution. Other significant factors affecting the evolution of the defect distribution are the large differences in mobility and stability of vacancy and interstitial defects and the rapid one-dimensional diffusion of small, glissile interstitial loops produced directly in cascades. Annealing simulations are also performed on high-energy, subcascade-producing cascades generated with the binary collision approximation and calibrated to MD results.

  16. An Experimental Approach to Simulations of the CLIC Interaction Point

    DEFF Research Database (Denmark)

    Esberg, Jakob

    2012-01-01

    with respect to the luminosity weighted depolarization is discussed. In the chapter on muons, the implementation of the production of incoherent muons in GUINEA-PIG++ will be discussed. Comments on the correctness and completeness of the implementation of muon production will be presented. The chapter...... experiments conducted at MAMI will be presented. Furthermore the chapter discusses the performance of new CMOS based detectors to be used in future experiments by the NA63 collaboration. The chapter on collider simulations introduces the beam-beam simulation codes GUINEA-PIG and GUINEA-PIG++, their methods...... of operation and their features. The characteristics of the simulated particles are presented and a comparison between the outputs of these codes with those from CAIN. \\item In the chapter on tridents, the implementation of the direct trident process in GUINEA-PIG++ is described. The results are compared...

  17. APPLICATION OF INTERACTIVE ONLINE SIMULATIONS IN THE PHYSICS LABORATORY ACTIVITIES

    Directory of Open Access Journals (Sweden)

    Nina P. Dementievska

    2013-09-01

    Full Text Available Physics teachers should have professional competences, aimed at the use of online technologies associated with physical experiments. Lack of teaching materials for teachers in Ukrainian language leads to the use of virtual laboratories and computer simulations by traditional methods of education, not by the latest innovative modern educational technology, which may limit their use and greatly reduce their effectiveness. Ukrainian teaching literature has practically no information about the assessment of competencies, research skills of students for the laboratory activities. The aim of the article is to describe some components of instructional design for the Web site with simulations in school physical experiments and their evaluation.

  18. Simulation of semi-artificial interaction events of cosmic radiation in the atmosphere

    International Nuclear Information System (INIS)

    Ferreira, L.C.A.

    1986-01-01

    A simulation of artifitial A-jets was performed, using the data of observed C-jets, aiming to study the atmospheric interactions. A comparative study on artifitial A-jets with observed A-jets, considering initially, only one interaction and then, introducing the possibility of successive interactions, is presented. A process denominated ''descascatizacao'' for one interaction stage is evaluated. (M.C.K.) [pt

  19. Progress of laser-plasma interaction simulations with the particle-in-cell code

    International Nuclear Information System (INIS)

    Sakagami, Hitoshi; Kishimoto, Yasuaki; Sentoku, Yasuhiko; Taguchi, Toshihiro

    2005-01-01

    As the laser-plasma interaction is a non-equilibrium, non-linear and relativistic phenomenon, we must introduce a microscopic method, namely, the relativistic electromagnetic PIC (Particle-In-Cell) simulation code. The PIC code requires a huge number of particles to validate simulation results, and its task is very computation-intensive. Thus simulation researches by the PIC code have been progressing along with advances in computer technology. Recently, parallel computers with tremendous computational power have become available, and thus we can perform three-dimensional PIC simulations for the laser-plasma interaction to investigate laser fusion. Some simulation results are shown with figures. We discuss a recent trend of large-scale PIC simulations that enable direct comparison between experimental facts and computational results. We also discharge/lightning simulations by the extended PIC code, which include various atomic and relaxation processes. (author)

  20. Plasma-material interaction under simulated disruption conditions

    International Nuclear Information System (INIS)

    Arkhipov, N.I.; Bakhtin, V.P.; Safronov, V.M.; Toporkov, D.A.; Vasenin, S.G.; Wurz, H.; Zhitlukhin, A.M.

    1995-01-01

    Sudden evaporation of divertor plate surface under high heat load during tokamak plasma disruption instantaneously produces a vapor shield. The cloud of vaporized material prevents the divertor plates from the bulk of incoming energy flux and thus reduces the further material erosion. Dynamics and effectiveness of the vapor shield are studied experimentally at the 2MK-200 facility under simulated disruption conditions. (orig.)

  1. Good experiences with interactive temporal bone surgical simulator

    DEFF Research Database (Denmark)

    Andersen, Steven A W; Mikkelsen, Peter Trier; Noe, Karsten Ostergaard

    2014-01-01

    time. In a multilingual user interface the integrated tutor function provides stepwise instructions during drilling through an intuitive, volumetric approach. A censor function draws on metrics derived from the simulator to provide instant and summary feedback for the user. The VES can be downloaded...

  2. Simulating market dynamics : Interactions between consumer psychology and social networks

    NARCIS (Netherlands)

    Janssen, M.A; Jager, W.

    2003-01-01

    Markets can show different types of dynamics, from quiet markets dominated by one or a few products, to markets with continual penetration of new and reintroduced products. in a previous article we explored the dynamics of markets from a psychological perspective using a multi-agent simulation

  3. Interactive X-ray and proton therapy training and simulation.

    Science.gov (United States)

    Hamza-Lup, Felix G; Farrar, Shane; Leon, Erik

    2015-10-01

    External beam X-ray therapy (XRT) and proton therapy (PT) are effective and widely accepted forms of treatment for many types of cancer. However, the procedures require extensive computerized planning. Current planning systems for both XRT and PT have insufficient visual aid to combine real patient data with the treatment device geometry to account for unforeseen collisions among system components and the patient. The 3D surface representation (S-rep) is a widely used scheme to create 3D models of physical objects. 3D S-reps have been successfully used in CAD/CAM and, in conjunction with texture mapping, in the modern gaming industry to customize avatars and improve the gaming realism and sense of presence. We are proposing a cost-effective method to extract patient-specific S-reps in real time and combine them with the treatment system geometry to provide a comprehensive simulation of the XRT/PT treatment room. The X3D standard is used to implement and deploy the simulator on the web, enabling its use not only for remote specialists' collaboration, simulation, and training, but also for patient education. An objective assessment of the accuracy of the S-reps obtained proves the potential of the simulator for clinical use.

  4. PhET Interactive Simulations: Transformative Tools for Teaching Chemistry

    Science.gov (United States)

    Moore, Emily B.; Chamberlain, Julia M.; Parson, Robert; Perkins, Katherine K.

    2014-01-01

    Developing fluency across symbolic-, macroscopic-, and particulate-level representations is central to learning chemistry. Within the chemistry education community, animations and simulations that support multi-representational fluency are considered critical. With advances in the accessibility and sophistication of technology,…

  5. Simulation of interaction between wind farm and power system

    DEFF Research Database (Denmark)

    Sørensen, Poul Ejnar; Hansen, Anca Daniela; Janosi, L.

    2002-01-01

    A dynamic model of the wind farm Hagesholm has been implemented in the dedicated power system simulation program DIgSILENT. The wind farm con- sists of six 2MW NM2000/72 wind turbines from NEG-Micon. The model has been verified using simultaneous powerquality measurements on the 10 kV terminals...

  6. Influence of World and Gravity Model Selection on Surface Interacting Vehicle Simulations

    Science.gov (United States)

    Madden, Michael M.

    2007-01-01

    A vehicle simulation is surface-interacting if the state of the vehicle (position, velocity, and acceleration) relative to the surface is important. Surface-interacting simulations perform ascent, entry, descent, landing, surface travel, or atmospheric flight. Modeling of gravity is an influential environmental factor for surface-interacting simulations. Gravity is the free-fall acceleration observed from a world-fixed frame that rotates with the world. Thus, gravity is the sum of gravitation and the centrifugal acceleration due to the world s rotation. In surface-interacting simulations, the fidelity of gravity at heights above the surface is more significant than gravity fidelity at locations in inertial space. A surface-interacting simulation cannot treat the gravity model separately from the world model, which simulates the motion and shape of the world. The world model's simulation of the world's rotation, or lack thereof, produces the centrifugal acceleration component of gravity. The world model s reproduction of the world's shape will produce different positions relative to the world center for a given height above the surface. These differences produce variations in the gravitation component of gravity. This paper examines the actual performance of world and gravity/gravitation pairs in a simulation using the Earth.

  7. Towards a simulation of disordered systems with interactions

    International Nuclear Information System (INIS)

    MacKinnon, Angus

    2008-01-01

    We consider the problem of Anderson localization in disordered systems with interactions. We present a numerical approach in quasi-one-dimensional (quasi-1D) systems which combines aspects of the transfer matrix and Green's function recursion methods with the density matrix renormalization group. The method is applied to spinless fermions in 1D and a generalization to finite cross-sections is outlined

  8. Numerical simulation of SMART-1 Hall-thruster plasma interactions

    NARCIS (Netherlands)

    Tajmar, Martin; Sedmik, René; Scharlemann, Carsten

    2009-01-01

    SMART-1 has been the first European mission using a Hall thruster to reach the moon. An onboard plasma diagnostic package allowed a detailed characterization of the thruster exhaust plasma and its interactions with the spacecraft. Analysis of in-flight data revealed, amongst others, an unpredicted

  9. Humans, computers and wizards human (simulated) computer interaction

    CERN Document Server

    Fraser, Norman; McGlashan, Scott; Wooffitt, Robin

    2013-01-01

    Using data taken from a major European Union funded project on speech understanding, the SunDial project, this book considers current perspectives on human computer interaction and argues for the value of an approach taken from sociology which is based on conversation analysis.

  10. Molecular simulations of lipid-mediated protein-protein interactions

    NARCIS (Netherlands)

    de Meyer, F.J.M.; Venturoli, M.; Smit, B.

    2008-01-01

    Recent experimental results revealed that lipid-mediated interactions due to hydrophobic forces may be important in determining the protein topology after insertion in the membrane, in regulating the protein activity, in protein aggregation and in signal transduction. To gain insight into the

  11. Simulating the interaction of galaxies and the intergalactic medium

    Science.gov (United States)

    Carin, Robert A.

    2008-11-01

    The co-evolution of galaxies and the intergalactic medium as a function of environment is studied using hydrodynamic simulations of the ΛCDM cosmogony. It is demonstrated with non-radiative calculations that, in the absence of non-gravitational mechanisms, dark matter haloes accrete a near-universal fraction (˜ 0.9Ω_{b}/&Omega_;{m}) of baryons. The absence of a mass or redshift dependence of this fraction augurs well for parameter tests that use X-ray clusters as cosmological probes. Moreover, this result indicates that non-gravitational processes must efficiently regulate the formation of stars in dark matter haloes if the halo mass function is to be reconciled with the observed galaxy luminosity function. Simulations featuring stellar evolution and non-gravitational feedback mechanisms (photo-heating by the ultraviolet background, and thermal and kinetic supernovae feedback) are used to follow the evolution of star formation, and the thermo- and chemo-dynamical evolution of baryons. The observed star formation history of the Universe is reproduced, except at low redshift where it is overestimated by a factor of a few, possibly indicating the need for feedback from active galactic nuclei to quench cooling flows around massive galaxies. The simulations more accurately reproduce the observed abundance of galaxies with late-type morphologies than has been reported elsewhere. The unique initial conditions of these simulations, based on the Millennium Simulation, allow an unprecedented study of the role of large-scale environment to be conducted. The cosmic star formation rate density is found to vary by an order of magnitude across the extremes of environment expected in the local Universe. The mass fraction of baryons in the observationally elusive warm-hot intergalactic medium (WHIM), and the volume filling factor that this gas occupies, is also shown to vary by a factor of a few across such environments. This variation is attributed to differences in the halo

  12. Social interaction, globalization and computer-aided analysis a practical guide to developing social simulation

    CERN Document Server

    Osherenko, Alexander

    2014-01-01

    This thorough, multidisciplinary study discusses the findings of social interaction and social simulation using understandable global examples. Shows the reader how to acquire intercultural data, illustrating each step with descriptive comments and program code.

  13. RadSim: a program to simulate individual particle interactions for educational purposes

    International Nuclear Information System (INIS)

    Verhaegen, Frank; Palefsky, Steven; DeBlois, Francois

    2006-01-01

    A program was developed, RadSim, which can be used to simulate certain individual interactions of photons, electrons, positrons and alpha particles with a single atom for educational purposes. The program can be run in two modes: manual and simulated. In the manual mode, an individual particle undergoing a specified interaction with a target atom can be simulated, which essentially comes down to a graphical evaluation of kinematic equations. In the simulated mode, a preset number of identical particles are allowed to undergo a specified interaction type with a target atom. The exit channel of the interaction is sampled from probability distributions using Monte Carlo methods. The incoming and outgoing particles are visualized and the frequency distribution of the kinematic variables of the exit channel is displayed graphically. It has to be emphasized that RadSim was mainly developed for educational purposes. (note)

  14. CDP a graphic system for the interactive simulation and the dynamic analysis of continuous systems

    International Nuclear Information System (INIS)

    Ricci, A.; Teolis, A.

    1973-01-01

    An IBM 2250 graphic system for the interactive simulation of continuous sytems is illustrated. Time dependent quantities can be plotted or an animated, real or schematic, representation of the system being studied can be given

  15. Process monitoring and simulation code verification using interactive computer animation

    International Nuclear Information System (INIS)

    Curtis, J.N.; Beelman, R.J.; Schwieder, D.H.; Stewart, H.D.

    1984-01-01

    At the Idaho National Engineering Laboratory (INEL), EG and G Idaho, Inc., has developed techniques by which schematics, created for and displayed at color graphics terminals, can be driven by actual or calculated data. These input data cause changes to occur within the displayed schematic. This research is presently being done to develop a prototype to be used in nuclear power plant control rooms. Work stations have already been developed to analyze data that are produced during actual and simulated nuclear reactor experiments

  16. Enhancing food engineering education with interactive web-based simulations

    OpenAIRE

    Alexandros Koulouris; Georgios Aroutidis; Dimitrios Vardalis; Petros Giannoulis; Paraskevi Karakosta

    2015-01-01

    In the traditional deductive approach in teaching any engineering topic, teachers would first expose students to the derivation of the equations that govern the behavior of a physical system and then demonstrate the use of equations through a limited number of textbook examples. This methodology, however, is rarely adequate to unmask the cause-effect and quantitative relationships between the system variables that the equations embody. Web-based simulation, which is the integration of simulat...

  17. A Framework for the Interactive Handling of High-Dimensional Simulation Data in Complex Geometries

    KAUST Repository

    Benzina, Amal; Buse, Gerrit; Butnaru, Daniel; Murarasu, Alin; Treib, Marc; Varduhn, Vasco; Mundani, Ralf-Peter

    2013-01-01

    Flow simulations around building infrastructure models involve large scale complex geometries, which when discretized in adequate detail entail high computational cost. Moreover, tasks such as simulation insight by steering or optimization require many such costly simulations. In this paper, we illustrate the whole pipeline of an integrated solution for interactive computational steering, developed for complex flow simulation scenarios that depend on a moderate number of both geometric and physical parameters. A mesh generator takes building information model input data and outputs a valid cartesian discretization. A sparse-grids-based surrogate model—a less costly substitute for the parameterized simulation—uses precomputed data to deliver approximated simulation results at interactive rates. Furthermore, a distributed multi-display visualization environment shows building infrastructure together with flow data. The focus is set on scalability and intuitive user interaction.

  18. Simulating shock-bubble interactions at water-gelatin interfaces

    Science.gov (United States)

    Adami, Stefan; Kaiser, Jakob; Bermejo-Moreno, Ivan; Adams, Nikolaus

    2016-11-01

    Biomedical problems are often driven by fluid dynamics, as in vivo organisms are usually composed of or filled with fluids that (strongly) affected their physics. Additionally, fluid dynamical effects can be used to enhance certain phenomena or destroy organisms. As examples, we highlight the benign potential of shockwave-driven kidney-stone lithotripsy or sonoporation (acoustic cavitation of microbubbles) to improve drug delivery into cells. During the CTR SummerProgram 2016 we have performed axisymmetric three-phase simulations of a shock hitting a gas bubble in water near a gelatin interface mimicking the fundamental process during sonoporation. We used our multi-resolution finite volume method with sharp interface representation (level-set), WENO-5 shock capturing and interface scale-separation and compared the results with a diffuse-interface method. Qualitatively our simulation results agree well with the reference. Due to the interface treatment the pressure profiles are sharper in our simulations and bubble collapse dynamics are predicted at shorter time-scales. Validation with free-field collapse (Rayleigh collapse) shows very good agreement. The project leading to this application has received funding from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programme (Grant agreement No 667483).

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

    Science.gov (United States)

    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.

  20. Intermolecular Interactions and Cooperative Effects from Electronic Structure Calculations: An Effective Means for Developing Interaction Potentials for Condensed Phase Simulations

    Energy Technology Data Exchange (ETDEWEB)

    Xantheas, Sotiris S.

    2004-05-01

    The modeling of the macroscopic properties of homogeneous and inhomogeneous systems via atomistic simulations such as molecular dynamics (MD) or Monte Carlo (MC) techniques is based on the accurate description of the relevant solvent-solute and solvent-solvent intermolecular interactions. The total energy (U) of an n-body molecular system can be formally written as [1,2,3

  1. Development of a Strategy for Simulating Blast-Vehicle Interactions

    Science.gov (United States)

    2010-09-01

    Magnus effect . Although large rotational speeds were measured, it was concluded that the Magnus force had little influence and did not significantly...CHEM (rigid flat-plate). 104 Figure 5.3: Geometry used for blast wave interacting with a cylinder (Ofengeim and Drikakis 1997). 105 Figure 5.4: CFD...their effects on vehicles and their human occupants. The framework couples the MPMICE CFD code with DYNA3D and LS-DYNA finite element codes

  2. D-VASim: An Interactive Virtual Laboratory Environment for the Simulation and Analysis of Genetic Circuits

    DEFF Research Database (Denmark)

    Baig, Hasan; Madsen, Jan

    2016-01-01

    runtime. The runtime interaction gives the user a feeling of being in the lab performing a real world experiment. In this work, we present a user-friendly software tool named D-VASim (Dynamic Virtual Analyzer and Simulator), which provides a virtual laboratory environment to simulate and analyze...

  3. SIDAS - a block-diagram programming system for the interactive digital simulation of dynamic systems

    International Nuclear Information System (INIS)

    Moll, H.; Burkhardt, H.

    1978-01-01

    The paper describes a block-oriented digital simulation system. Some applications clarify the basic structure and operation. The main features of the system are: Easy handling and manipulation through interactive graphical input/output, operational flexibility through successive simulation runs and online modification of parameters, direct access to all facilities of a medium-sized computing system. (orig.) [de

  4. Statistical analysis of simulation calculation of sputtering for two interaction potentials

    International Nuclear Information System (INIS)

    Shao Qiyun

    1992-01-01

    The effects of the interaction potentials (Moliere potential and Universal potential) are presented on computer simulation results of sputtering via Monte Carlo simulation based on the binary collision approximation. By means of Wilcoxon two-Sample paired sign rank test, the statistically significant difference for the above results is obtained

  5. WinGraphics: An optimized windowing environment for interactive real-time simulations

    International Nuclear Information System (INIS)

    Verboncoeur, J.P.; Vahedi, V.

    1989-01-01

    We have developed a customized windowing environment, Win Graphics, which provides particle simulation codes with an interactive user interface. The environment supports real-time animation of the simulation, displaying multiple diagnostics as they evolve in time. In addition, keyboard and printer (PostScript and dot matrix) support is provided. This paper describes this environment

  6. Design and Application of Interactive Simulations in Problem-Solving in University-Level Physics Education

    Science.gov (United States)

    Ceberio, Mikel; Almudí, José Manuel; Franco, Ángel

    2016-01-01

    In recent years, interactive computer simulations have been progressively integrated in the teaching of the sciences and have contributed significant improvements in the teaching-learning process. Practicing problem-solving is a key factor in science and engineering education. The aim of this study was to design simulation-based problem-solving…

  7. Simulation of wire-compensation of long range beam beam interaction in high energy accelerators

    International Nuclear Information System (INIS)

    Dorda, U.; )

    2006-01-01

    Full text: We present weak-strong simulation results for the effect of long-range beam-beam (LRBB) interaction in LHC as well as for proposed wire compensation schemes or wire experiments, respectively. In particular, we discuss details of the simulation model, instability indicators, the effectiveness of compensation, the difference between nominal and PACMAN bunches for the LHC, beam experiments, and wire tolerances. The simulations are performed with the new code BBTrack. (author)

  8. Simulation of Martian surface-atmosphere interaction in a space-simulator: Technical considerations and feasibility

    Science.gov (United States)

    Moehlmann, D.; Kochan, H.

    1992-01-01

    The Space Simulator of the German Aerospace Research Establishment at Cologne, formerly used for testing satellites, is now, since 1987, the central unit within the research sub-program 'Comet-Simulation' (KOSI). The KOSI team has investigated physical processes relevant to comets and their surfaces. As a byproduct we gained experience in sample-handling under simulated space conditions. In broadening the scope of the research activities of the DLR Institute of Space Simulation an extension to 'Laboratory-Planetology' is planned. Following the KOSI-experiments a Mars Surface-Simulation with realistic minerals and surface soil in a suited environment (temperature, pressure, and CO2-atmosphere) is foreseen as the next step. Here, our main interest is centered on thermophysical properties of the Martian surface and energy transport (and related gas transport) through the surface. These laboratory simulation activities can be related to space missions as typical pre-mission and during-the-mission support of the experiments design and operations (simulation in parallel). Post mission experiments for confirmation and interpretation of results are of great value. The physical dimensions of the Space Simulator (cylinder of about 2.5 m diameter and 5 m length) allows for testing and qualification of experimental hardware under realistic Martian conditions.

  9. Microwave simulation of laser plasma interactions. Final report

    International Nuclear Information System (INIS)

    1977-01-01

    Various electron and ion current, electric field, and magnetic field probes were developed and tested during the course of the investigation. A three dimensional probe drive system was constructed in order to investigate two and three dimensional phenomena occurring in the microwave plasma interaction. In most of the experiments reported here, a 1 GHz, 40 kilowatt, pulsed rf source (Applied Microwave), was used. The antenna was a 20 0 horn. A dipole fed parabolic antenna system capable of producing a focussed microwave beam at 2.3 GHz was developed and bench tested. This system will be used in future investigations at higher power levels

  10. 3d particle simulations on ultra short laser interaction

    Energy Technology Data Exchange (ETDEWEB)

    Nishihara, Katsunobu; Okamoto, Takashi; Yasui, Hidekazu [Osaka Univ., Suita (Japan). Inst. of Laser Engineering

    1998-03-01

    Two topics related to ultra short laser interaction with matter, linear and nonlinear high frequency conductivity of a solid density hydrogen plasma and anisotropic self-focusing of an intense laser in an overdense plasma, have been investigated with the use of 3-d particle codes. Frequency dependence of linear conductivity in a dense plasma is obtained, which shows anomalous conductivity near plasma frequency. Since nonlinear conductivity decreases with v{sub o}{sup -3}, where v{sub o} is a quivering velocity, an optimum amplitude exists leading to a maximum electron heating. Anisotropic self-focusing of a linear polarized intense laser is observed in an overdense plasma. (author)

  11. Depletion interactions in two-dimensional colloid-polymer mixtures: molecular dynamics simulations

    International Nuclear Information System (INIS)

    Kim, Soon-Chul; Seong, Baek-Seok; Suh, Soong-Hyuck

    2009-01-01

    The depletion interactions acting between two hard colloids immersed in a bath of polymers, in which the interaction potentials include the soft repulsion/attraction, are extensively studied by using the molecular dynamics simulations. The collision frequencies and collision angle distributions for both incidental and reflection conditions are computed to study the dynamic properties of the colloidal mixtures. The depletion effect induced by the polymer-polymer and colloid-polymer interactions are investigated as well as the size ratio of the colloid and polymer. The simulated results show that the strong depletion interaction between two hard colloids appears for the highly asymmetric hard-disc mixtures. The attractive depletion force at contact becomes deeper and the repulsive barrier becomes wider as the asymmetry in size ratio increases. The strong polymer-polymer attraction leads to the purely attractive depletion interaction between two hard colloids, whereas the purely repulsive depletion interaction is induced by the strong colloid-polymer attraction.

  12. Modeling and Simulation of Microelectrode-Retina Interactions

    Energy Technology Data Exchange (ETDEWEB)

    Beckerman, M

    2002-11-30

    The goal of the retinal prosthesis project is the development of an implantable microelectrode array that can be used to supply visually-driven electrical input to cells in the retina, bypassing nonfunctional rod and cone cells, thereby restoring vision to blind individuals. This goal will be achieved through the study of the fundamentals of electrical engineering, vision research, and biomedical engineering with the aim of acquiring the knowledge needed to engineer a high-density microelectrode-tissue hybrid sensor that will restore vision to millions of blind persons. The modeling and simulation task within this project is intended to address the question how best to stimulate, and communicate with, cells in the retina using implanted microelectrodes.

  13. Interaction between the neoclassical equilibrium and microturbulence in gyrokinetic simulations

    Energy Technology Data Exchange (ETDEWEB)

    Oberparleiter, Michael

    2015-07-10

    For the application of the nuclear fusion of hydrogen as a heat source for electricity generation understanding of the magnetic fuel confinement is crucial. Most of the cross-field transport in modern-day tokamaks is carried by turbulence driven by steep pressure gradients. Background neoclassical transport, however, provides a steady level of cross-field flux even in cases when turbulence becomes weak or suppressed. The goal of this work is to quantify how neoclassical (NC) effects and turbulence can influence each other. For this purpose the nonlinear gyrokinetic turbulence code GENE is employed. Firstly, its ability to self-consistently calculate the NC radial electric field is successfully benchmarked against the radial force balance equation and NC transport in the plasma region close to the center of a tokamak is studied. In the next step a model system where a long-wavelength external potential is imposed on ion temperature gradient-driven (ITG) turbulence is investigated. It is found that the self-generated shear flow pattern of the turbulence adapts to the imposed pattern and a small external shear is sufficient to notably reduce turbulent transport. Motivated by this global ITG simulations with fixed pressure gradient profiles are performed with and without inclusion of NC effects. Their comparison reveals that the NC field enhances turbulent transport by 20-30 % for a ratio of ion gyroradius and device radius larger than 1/300. An explanation is that the NC field aligns a region of low shear with the maximum of the gradient profile where the turbulent drive is strongest. Further investigation reveals that NC effects also change the dependence of the system on collisionality or safety factor. Finally, in physically more comprehensive simulations with fixed power input and a self-consistently evolving temperature profile, the additional NC transport channel is found to reduce the frequency and amplitude of intermittent turbulent transport bursts.

  14. Interactive virtual simulation using a 3D computer graphics model for microvascular decompression surgery.

    Science.gov (United States)

    Oishi, Makoto; Fukuda, Masafumi; Hiraishi, Tetsuya; Yajima, Naoki; Sato, Yosuke; Fujii, Yukihiko

    2012-09-01

    The purpose of this paper is to report on the authors' advanced presurgical interactive virtual simulation technique using a 3D computer graphics model for microvascular decompression (MVD) surgery. The authors performed interactive virtual simulation prior to surgery in 26 patients with trigeminal neuralgia or hemifacial spasm. The 3D computer graphics models for interactive virtual simulation were composed of the brainstem, cerebellum, cranial nerves, vessels, and skull individually created by the image analysis, including segmentation, surface rendering, and data fusion for data collected by 3-T MRI and 64-row multidetector CT systems. Interactive virtual simulation was performed by employing novel computer-aided design software with manipulation of a haptic device to imitate the surgical procedures of bone drilling and retraction of the cerebellum. The findings were compared with intraoperative findings. In all patients, interactive virtual simulation provided detailed and realistic surgical perspectives, of sufficient quality, representing the lateral suboccipital route. The causes of trigeminal neuralgia or hemifacial spasm determined by observing 3D computer graphics models were concordant with those identified intraoperatively in 25 (96%) of 26 patients, which was a significantly higher rate than the 73% concordance rate (concordance in 19 of 26 patients) obtained by review of 2D images only (p computer graphics model provided a realistic environment for performing virtual simulations prior to MVD surgery and enabled us to ascertain complex microsurgical anatomy.

  15. DYNECHARM++: a toolkit to simulate coherent interactions of high-energy charged particles in complex structures

    Science.gov (United States)

    Bagli, Enrico; Guidi, Vincenzo

    2013-08-01

    A toolkit for the simulation of coherent interactions between high-energy charged particles and complex crystal structures, called DYNECHARM++ has been developed. The code has been written in C++ language taking advantage of this object-oriented programing method. The code is capable to evaluating the electrical characteristics of complex atomic structures and to simulate and track the particle trajectory within them. Calculation method of electrical characteristics based on their expansion in Fourier series has been adopted. Two different approaches to simulate the interaction have been adopted, relying on the full integration of particle trajectories under the continuum potential approximation and on the definition of cross-sections of coherent processes. Finally, the code has proved to reproduce experimental results and to simulate interaction of charged particles with complex structures.

  16. Winters fuels report

    International Nuclear Information System (INIS)

    1995-01-01

    The outlook for distillate fuel oil this winter is for increased demand and a return to normal inventory patterns, assuming a resumption of normal, cooler weather than last winter. With industrial production expected to grow slightly from last winter's pace, overall consumption is projected to increase 3 percent from last winter, to 3.4 million barrels per day during the heating season (October 1, 1995-March 31, 1996). Much of the supply win come from stock drawdowns and refinery production. Estimates for the winter are from the Energy Information Administration's (EIA) 4th Quarter 1995 Short-Tenn Energy Outlook (STEO) Mid-World Oil Price Case forecast. Inventories in place on September 30, 1995, of 132 million barrels were 9 percent below the unusually high year-earlier level. Inventories of high-sulfur distillate fuel oil, the principal type used for heating, were 13 percent lower than a year earlier. Supply problems are not anticipated because refinery production and the ready availability of imports should be adequate to meet demand. Residential heating off prices are expected to be somewhat higher than last winter's, as the effects of lower crude oil prices are offset by lower distillate inventories. Heating oil is forecast to average $0.92 per gallon, the highest price since the winter of 1992-93. Diesel fuel (including tax) is predicted to be slightly higher than last year at $1.13 per gallon. This article focuses on the winter assessment for distillate fuel oil, how well last year's STEO winter outlook compared to actual events, and expectations for the coming winter. Additional analyses include regional low-sulfur and high-sulfur distillate supply, demand, and prices, and recent trends in distillate fuel oil inventories

  17. Interactive Learning Environment: Web-based Virtual Hydrological Simulation System using Augmented and Immersive Reality

    Science.gov (United States)

    Demir, I.

    2014-12-01

    Recent developments in internet technologies make it possible to manage and visualize large data on the web. Novel visualization techniques and interactive user interfaces allow users to create realistic environments, and interact with data to gain insight from simulations and environmental observations. The hydrological simulation system is a web-based 3D interactive learning environment for teaching hydrological processes and concepts. The simulation systems provides a visually striking platform with realistic terrain information, and water simulation. Students can create or load predefined scenarios, control environmental parameters, and evaluate environmental mitigation alternatives. The web-based simulation system provides an environment for students to learn about the hydrological processes (e.g. flooding and flood damage), and effects of development and human activity in the floodplain. The system utilizes latest web technologies and graphics processing unit (GPU) for water simulation and object collisions on the terrain. Users can access the system in three visualization modes including virtual reality, augmented reality, and immersive reality using heads-up display. The system provides various scenarios customized to fit the age and education level of various users. This presentation provides an overview of the web-based flood simulation system, and demonstrates the capabilities of the system for various visualization and interaction modes.

  18. Klaus Winter (1930 - 2015)

    CERN Multimedia

    2015-01-01

    We learned with great sadness that Klaus Winter passed away on 9 February 2015, after a long illness.   Klaus was born in 1930 in Hamburg, where he obtained his diploma in physics in 1955. From 1955 to 1958 he held a scholarship at the Collège de France, where he received his doctorate in nuclear physics under the guidance of Francis Perrin. Klaus joined CERN in 1958, where he first participated in experiments on π+ and K0 decay properties at the PS, and later became the spokesperson of the CHOV Collaboration at the ISR. Starting in 1976, his work focused on experiments with the SPS neutrino beam. In 1984 he joined Ugo Amaldi to head the CHARM experiment, designed for detailed studies of the neutral current interactions of high-energy neutrinos, which had been discovered in 1973 using the Gargamelle bubble chamber at the PS. The unique feature of the detector was its target calorimeter, which used large Carrara marble plates as an absorber material. From 1984 to 1991, Klau...

  19. A study of the use of simulated work task situations in interactive information retrieval evaluations

    DEFF Research Database (Denmark)

    Borlund, Pia

    2016-01-01

    Purpose – The purpose of this paper is to report a study of how the test instrument of a simulated work task situation is used in empirical evaluations of interactive information retrieval (IIR) and reported in the research literature. In particular, the author is interested to learn whether....... The paper addresses the need to carefully design and tailor simulated work task situations to suit the test participants in order to obtain the intended authentic and realistic IIR under study. Keywords Interactive information retrieval study, IIR study, Test design, Simulated work task situations, Meta-evaluation...... situations in IIR evaluations. In particular, with respect to the design and creation of realistic simulated work task situations. There is a lack of tailoring of the simulated work task situations to the test participants. Likewise, the requirement to include the test participants’ personal information...

  20. KAPOOL experiments to simulate molten corium - sacrificial concrete interaction

    International Nuclear Information System (INIS)

    Eppinger, B.; Fieg, G.; Tromm, W.

    2001-01-01

    In future Light Water Reactors special devices (core catchers) might be required to prevent containment failure by basement erosion after reactor pressure vessel melt-through during a core meltdown accident. In the planned European Pressurized Reactor (EPR) the core melt is retained in the reactor cavity for ∼ 1 h to pick up late melts after the failure of the reactor pressure vessel. The reactor cavity is protected by a layer of sacrificial concrete and closed by a melt gate at the bottom towards the spreading compartment. After erosion of the sacrificial concrete and melt-through of the gate the core melt should be distributed homogeneously into the spreading compartment. There the melt is cooled by flooding with water. The knowledge of the sacrificial concrete erosion phase in the reactor cavity is essential for the severe accident assessment. Several KAPOOL experiments have been performed to investigate the erosion of two possible compositions of sacrificial concretes using alumina-iron thermite melts as a simulant for the core melt. Erosion rates as a function of the melt temperature and the inhomogeneity of the melt front are presented in this paper. (authors)

  1. Driving engineering of novel antimicrobial peptides from simulations of peptide-micelle interactions

    DEFF Research Database (Denmark)

    Khandelia, Himanshu; Langham, Allison A; Kaznessis, Yiannis N

    2006-01-01

    Simulations of antimicrobial peptides in membrane mimics can provide the high resolution, atomistic picture that is necessary to decipher which sequence and structure components are responsible for activity and toxicity. With such detailed insight, engineering new sequences that are active but non...... peptides and their interaction with membrane mimics. In this article, we discuss the promise and the challenges of widely used models and detail our recent work on peptide-micelle simulations as an attractive alternative to peptide-bilayer simulations. We detail our results with two large structural...... classes of peptides, helical and beta-sheet and demonstrate how simulations can assist in engineering of novel antimicrobials with therapeutic potential....

  2. Simulating the fluid-structure interaction of a flexible tube in an array of rigid tubes

    International Nuclear Information System (INIS)

    Warnica, D.; Maleki, M.; Hariri, A.; Feldman, H.

    2011-01-01

    Two important single-phase mechanisms for flow-induced vibration of heat-exchanger tube bundles were used to demonstrate the capabilities of commercial software to simulate unsteady fluid-structure interactions (FSI). Reasonable agreement was obtained between the FSI simulations and experimental data for the onset of fluid elastic instability. There was also reasonable agreement between the FSI simulations and empirical correlations for the dynamic tube response to random turbulence excitation. Additional benefits of performing FSI simulations were the ability to characterize important features of the unsteady flow fields and hydrodynamic parameters such as viscous damping coefficients, which would otherwise require elaborate experimental measurements. (author)

  3. Computer Networks E-learning Based on Interactive Simulations and SCORM

    Directory of Open Access Journals (Sweden)

    Francisco Andrés Candelas

    2011-05-01

    Full Text Available This paper introduces a new set of compact interactive simulations developed for the constructive learning of computer networks concepts. These simulations, which compose a virtual laboratory implemented as portable Java applets, have been created by combining EJS (Easy Java Simulations with the KivaNS API. Furthermore, in this work, the skills and motivation level acquired by the students are evaluated and measured when these simulations are combined with Moodle and SCORM (Sharable Content Object Reference Model documents. This study has been developed to improve and stimulate the autonomous constructive learning in addition to provide timetable flexibility for a Computer Networks subject.

  4. Numerical simulation of fluid structure interaction in two flexible tubes

    International Nuclear Information System (INIS)

    Feng Zhipeng; Zang Fenggang; Zhang Yixiong

    2014-01-01

    In order to further investigate fluid structure interaction problems, occurring in the nuclear field such as the behavior of PWR fuel rods, steam generator and other heat exchanger tubes, a numerical model was presented. It is a three-dimensional fully coupled approach with solving the fluid flow and the structure vibration simultaneously, for the tube bundles in cross flow. The unsteady three-dimensional Navier-Stokes equation and LES turbulence model were solved with finite volume approach on structured grids combined with the technique of dynamic mesh. The dynamic equilibrium equation was discretized according to the finite element theory. The vibration response of a single tube in cross flow was calculated by the numerical model. Both the amplitude and frequency were compared with experimental data and existing models in the literature. It is shown that the present model is reasonable. The flow induced vibration characteristics, for both inline and parallel sets in cross flow, were investigated by the numerical model. The dynamic response and flow characteristics, for both inline tubes and parallel tubes with pitch ratio of 1.2, 1.6, 2, 3 and 4 under different incident velocities, were studied. Critical pitch and critical velocity were obtained. (authors)

  5. Molecular simulation of polar molecules interaction with MOFs family materials

    International Nuclear Information System (INIS)

    De Toni, M.

    2012-01-01

    The topic of this thesis is the adsorption of simple molecular fluids in nano-porous materials. Many industrial processes are based on this phenomenon, including ionic exchange, selective separation and heterogeneous catalysis. I used molecular simulation to study the adsorption properties of polar molecules of industrial interest (CO 2 and H 2 O) in a new class of crystalline microporous hybrid organic-inorganic materials called Metal-Organic Frameworks (MOFs). They have exceptional adsorption properties due to their topological variety and their versatility, allowed by the large range of possibilities offered by organic and coordination chemistry and functionalizations. I first studied the adsorption of CO 2 in a family of materials called IRMOFs, which share the same topology but have different porous volume, in order to characterize the effect of confinement on their adsorption performance. In particular, a general behavior has been highlighted: the critical temperature decreases when the confinement increases. Then, I looked at a recently synthesized cationic MOF called Zn2(CBTACN). After having localized the extra-framework halogen anions in the unit cell of the material, something which was not possible experimentally, I characterized CO 2 adsorption in this system first as a pure gas and then as a component of different mixtures. Finally, I was interested in the hydrothermal stability of MOFs, a crucial issue for their use in industrial applications. I observed the hydration mechanism of system that is analogous to the MOF-5 (IRMOF-0h) and shed light on some collaborative effects of the attack of water that were unknown to in the literature. (author)

  6. A novel approach to simulate gene-environment interactions in complex diseases

    Directory of Open Access Journals (Sweden)

    Nicodemi Mario

    2010-01-01

    Full Text Available Abstract Background Complex diseases are multifactorial traits caused by both genetic and environmental factors. They represent the major part of human diseases and include those with largest prevalence and mortality (cancer, heart disease, obesity, etc.. Despite a large amount of information that has been collected about both genetic and environmental risk factors, there are few examples of studies on their interactions in epidemiological literature. One reason can be the incomplete knowledge of the power of statistical methods designed to search for risk factors and their interactions in these data sets. An improvement in this direction would lead to a better understanding and description of gene-environment interactions. To this aim, a possible strategy is to challenge the different statistical methods against data sets where the underlying phenomenon is completely known and fully controllable, for example simulated ones. Results We present a mathematical approach that models gene-environment interactions. By this method it is possible to generate simulated populations having gene-environment interactions of any form, involving any number of genetic and environmental factors and also allowing non-linear interactions as epistasis. In particular, we implemented a simple version of this model in a Gene-Environment iNteraction Simulator (GENS, a tool designed to simulate case-control data sets where a one gene-one environment interaction influences the disease risk. The main aim has been to allow the input of population characteristics by using standard epidemiological measures and to implement constraints to make the simulator behaviour biologically meaningful. Conclusions By the multi-logistic model implemented in GENS it is possible to simulate case-control samples of complex disease where gene-environment interactions influence the disease risk. The user has full control of the main characteristics of the simulated population and a Monte

  7. VASA: Interactive Computational Steering of Large Asynchronous Simulation Pipelines for Societal Infrastructure.

    Science.gov (United States)

    Ko, Sungahn; Zhao, Jieqiong; Xia, Jing; Afzal, Shehzad; Wang, Xiaoyu; Abram, Greg; Elmqvist, Niklas; Kne, Len; Van Riper, David; Gaither, Kelly; Kennedy, Shaun; Tolone, William; Ribarsky, William; Ebert, David S

    2014-12-01

    We present VASA, a visual analytics platform consisting of a desktop application, a component model, and a suite of distributed simulation components for modeling the impact of societal threats such as weather, food contamination, and traffic on critical infrastructure such as supply chains, road networks, and power grids. Each component encapsulates a high-fidelity simulation model that together form an asynchronous simulation pipeline: a system of systems of individual simulations with a common data and parameter exchange format. At the heart of VASA is the Workbench, a visual analytics application providing three distinct features: (1) low-fidelity approximations of the distributed simulation components using local simulation proxies to enable analysts to interactively configure a simulation run; (2) computational steering mechanisms to manage the execution of individual simulation components; and (3) spatiotemporal and interactive methods to explore the combined results of a simulation run. We showcase the utility of the platform using examples involving supply chains during a hurricane as well as food contamination in a fast food restaurant chain.

  8. Interaction of Tenebrio Molitor Antifreeze Protein with Ice Crystal: Insights from Molecular Dynamics Simulations.

    Science.gov (United States)

    Ramya, L; Ramakrishnan, Vigneshwar

    2016-07-01

    Antifreeze proteins (AFP) observed in cold-adapting organisms bind to ice crystals and prevent further ice growth. However, the molecular mechanism of AFP-ice binding and AFP-inhibited ice growth remains unclear. Here we report the interaction of the insect antifreeze protein (Tenebrio molitor, TmAFP) with ice crystal by molecular dynamics simulation studies. Two sets of simulations were carried out at 263 K by placing the protein near the primary prism plane (PP) and basal plane (BL) of the ice crystal. To delineate the effect of temperatures, both the PP and BL simulations were carried out at 253 K as well. The analyses revealed that the protein interacts strongly with the ice crystal in BL simulation than in PP simulation both at 263 K and 253 K. Further, it was observed that the interactions are primarily mediated through the interface waters. We also observed that as the temperature decreases, the interaction between the protein and the ice increases which can be attributed to the decreased flexibility and the increased structuring of the protein at low temperature. In essence, our study has shed light on the interaction mechanism between the TmAFP antifreeze protein and the ice crystal. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. CFD simulation of two-sail interaction about a sailing yacht; Sailing Yacht no niyoku kansho no CFD simulation

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Y.; Miyata, H.; Sato, T. [The University of Tokyo, Tokyo (Japan). Faculty of Engineering

    1997-06-01

    Numerical analysis of sail characteristics was done by the finite volume method for an IACC class racing yacht, in compliance to the WISDAM-7 method for analyzing flow fields around the hull. The simulation code makes discrete the Navier-Stokes equation for non-compressive fluid in a conserved system by the finite volume method, and tries to find the solutions following the algorithm of the MAC method in a time-dependent manner. The H-H grids generated by an interface boundary technique for each sail are integrated for the two-sail configuration. It is found that combination of the finite volume method and grid integration is an adequate CFD procedure for simulation of interactions between the two sails. Performance of two-sail configuration, involving complex mechanisms such as interactions and separation of flows, is found by the method in which viscosity is taken into consideration. 5 refs., 20 figs., 3 tabs.

  10. DSMC simulation and experimental validation of shock interaction in hypersonic low density flow.

    Science.gov (United States)

    Xiao, Hong; Shang, Yuhe; Wu, Di

    2014-01-01

    Direct simulation Monte Carlo (DSMC) of shock interaction in hypersonic low density flow is developed. Three collision molecular models, including hard sphere (HS), variable hard sphere (VHS), and variable soft sphere (VSS), are employed in the DSMC study. The simulations of double-cone and Edney's type IV hypersonic shock interactions in low density flow are performed. Comparisons between DSMC and experimental data are conducted. Investigation of the double-cone hypersonic flow shows that three collision molecular models can predict the trend of pressure coefficient and the Stanton number. HS model shows the best agreement between DSMC simulation and experiment among three collision molecular models. Also, it shows that the agreement between DSMC and experiment is generally good for HS and VHS models in Edney's type IV shock interaction. However, it fails in the VSS model. Both double-cone and Edney's type IV shock interaction simulations show that the DSMC errors depend on the Knudsen number and the models employed for intermolecular interaction. With the increase in the Knudsen number, the DSMC error is decreased. The error is the smallest in HS compared with those in the VHS and VSS models. When the Knudsen number is in the level of 10(-4), the DSMC errors, for pressure coefficient, the Stanton number, and the scale of interaction region, are controlled within 10%.

  11. Winter Bottom Trawl Survey

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The standardized NEFSC Winter Bottom Trawl Survey was initiated in 1992 and covered offshore areas from the Mid-Atlantic to Georges Bank. Inshore strata were covered...

  12. Deer Wintering Areas

    Data.gov (United States)

    Vermont Center for Geographic Information — Deer winter habitat is critical to the long term survival of white-tailed deer (Odocoileus virginianus) in Vermont. Being near the northern extreme of the...

  13. Simbuca, using a graphics card to simulate Coulomb interactions in a penning trap

    CERN Document Server

    Van Gorp, S; Friedag, P; De Leebeeck, V; Tandecki, M; Weinheimer, C; Breitenfeldt, M; Traykov, E; Severijn, N; Mader, J; Soti, G; Iitaka, T; Herlert, A; Wauters, F; Zakoucky, D; Kozlov, V; Roccia, S

    2011-01-01

    In almost all cases, N-body simulations are limited by the computation time available. Coulomb interaction calculations scale with O(N(2)) with N the number of particles. Approximation methods exist already to reduce the computation time to O(NlogN) although calculating the interaction still dominates the total simulation time. We present Simbuca, a simulation package for thousands of ions moving in a Penning trap which will be applied for the WITCH experiment. Simbuca uses the output of the Cunbody-1 library, which calculates the gravitational interaction between entities on a graphics card, and adapts it for Coulomb calculations. Furthermore the program incorporates three realistic buffer gas models, the possibility of importing realistic electric and magnetic fieldmaps and different order integrators with adaptive step size and error control. The software is released under the GNU General Public License and free for use. Crown Copyright (C) 2010 Published by Elsevier B.V. All rights reserved.

  14. Simulation of isothermal multi-phase fuel-coolant interaction using MPS method with GPU acceleration

    Energy Technology Data Exchange (ETDEWEB)

    Gou, W.; Zhang, S.; Zheng, Y. [Zhejiang Univ., Hangzhou (China). Center for Engineering and Scientific Computation

    2016-07-15

    The energetic fuel-coolant interaction (FCI) has been one of the primary safety concerns in nuclear power plants. Graphical processing unit (GPU) implementation of the moving particle semi-implicit (MPS) method is presented and used to simulate the fuel coolant interaction problem. The governing equations are discretized with the particle interaction model of MPS. Detailed implementation on single-GPU is introduced. The three-dimensional broken dam is simulated to verify the developed GPU acceleration MPS method. The proposed GPU acceleration algorithm and developed code are then used to simulate the FCI problem. As a summary of results, the developed GPU-MPS method showed a good agreement with the experimental observation and theoretical prediction.

  15. Interactive use of simulation models for collaborative knowledge construction: the case of flood policy decision-making

    NARCIS (Netherlands)

    Leskens, Anne

    2015-01-01

    There is an increasing use of interactive flood simulation models in work sessions with practitioners, which is supposed to be more effective than feeding static model results from conventional simulation models into the decision-making process. These interactive simulation models rely on fast and

  16. Interactive Pre-Simulation Strategies: Engaging Students in Experiential Learning from the Start

    Directory of Open Access Journals (Sweden)

    Beverly J. D. Bye

    2014-02-01

    Full Text Available Decrease in clinical nursing facilities created a need to develop supplemental real-life patient scenarios outside of the traditional nursing units. Over the past five years, there has been a dramatic increase in the number of simulation exercises integrated into the clinical and classroom aspect of nursing education. However, many students are not engaged and are not effectively participating in the simulation. Many students state they are perplexed and do not understand the purpose and roles of simulation, and often do not take it seriously. The challenge to nurse educators is to develop realistic goals and objectives with a variety of activities that occur prior to the actual simulation experience Debriefing is one of the most important aspects of the simulation activity, but if students are not participating, then the learning is not occurring. The key with simulation is to engage students through the use of various strategies that incorporate visual, auditory, tactile, and cognitive learning prior to the simulation experience. This study investigated the use of interactive pre-simulation strategies such as concept mapping, group discussion, teaching, and body mapping prior to the simulation experience. The focus of this research was on student success and knowledge acquisition. The most important overall goal is to engage students prior to the simulation experience in a safe, nonthreatening learning environment in order to allay students' fear of failure and ultimately increase knowledge, retention, and critical thinking. Results of the study have implications on the development and integration of innovative teaching pedagogies.

  17. The influence of interactions between market segmentation strategy and competition on organizational performance. A simulation study.

    OpenAIRE

    Dolnicar, Sara; Freitag, Roman

    2003-01-01

    A computer simulation study is conducted to explore the interaction of alternative segmentation strategies and the competitiveness of the market environment, a goal that can neither be tackled by purely analytic approaches nor is sufficient and undistorted real market data available to deduct findings in an empirical manner. The fundamental idea of the simulation is to increase competition in the artificial marketplace and to study the influence of segmentation strategy and varying market con...

  18. Interactive fluka: a world wide web version for a simulation code in proton therapy

    International Nuclear Information System (INIS)

    Garelli, S.; Giordano, S.; Piemontese, G.; Squarcia, S.

    1998-01-01

    We considered the possibility of using the simulation code FLUKA, in the framework of TERA. We provided a window under World Wide Web in which an interactive version of the code is available. The user can find instructions for the installation, an on-line FLUKA manual and interactive windows for inserting all the data required by the configuration running file in a very simple way. The database choice allows a more versatile use for data verification and update, recall of old simulations and comparison with selected examples. A completely new tool for geometry drawing under Java has also been developed. (authors)

  19. Specific interactions between DNA and regulatory protein controlled by ligand-binding: Ab initio molecular simulation

    International Nuclear Information System (INIS)

    Matsushita, Y.; Murakawa, T.; Shimamura, K.; Oishi, M.; Ohyama, T.; Kurita, N.

    2015-01-01

    The catabolite activator protein (CAP) is one of the regulatory proteins controlling the transcription mechanism of gene. Biochemical experiments elucidated that the complex of CAP with cyclic AMP (cAMP) is indispensable for controlling the mechanism, while previous molecular simulations for the monomer of CAP+cAMP complex revealed the specific interactions between CAP and cAMP. However, the effect of cAMP-binding to CAP on the specific interactions between CAP and DNA is not elucidated at atomic and electronic levels. We here considered the ternary complex of CAP, cAMP and DNA in solvating water molecules and investigated the specific interactions between them at atomic and electronic levels using ab initio molecular simulations based on classical molecular dynamics and ab initio fragment molecular orbital methods. The results highlight the important amino acid residues of CAP for the interactions between CAP and cAMP and between CAP and DNA

  20. Specific interactions between DNA and regulatory protein controlled by ligand-binding: Ab initio molecular simulation

    Energy Technology Data Exchange (ETDEWEB)

    Matsushita, Y., E-mail: kurita@cs.tut.ac.jp; Murakawa, T., E-mail: kurita@cs.tut.ac.jp; Shimamura, K., E-mail: kurita@cs.tut.ac.jp; Oishi, M., E-mail: kurita@cs.tut.ac.jp; Ohyama, T., E-mail: kurita@cs.tut.ac.jp; Kurita, N., E-mail: kurita@cs.tut.ac.jp [Department of Computer Science and Engineering, Toyohashi University of Technology, Tempaku-cho, Toyohashi, Aichi, 441-8580 (Japan)

    2015-02-27

    The catabolite activator protein (CAP) is one of the regulatory proteins controlling the transcription mechanism of gene. Biochemical experiments elucidated that the complex of CAP with cyclic AMP (cAMP) is indispensable for controlling the mechanism, while previous molecular simulations for the monomer of CAP+cAMP complex revealed the specific interactions between CAP and cAMP. However, the effect of cAMP-binding to CAP on the specific interactions between CAP and DNA is not elucidated at atomic and electronic levels. We here considered the ternary complex of CAP, cAMP and DNA in solvating water molecules and investigated the specific interactions between them at atomic and electronic levels using ab initio molecular simulations based on classical molecular dynamics and ab initio fragment molecular orbital methods. The results highlight the important amino acid residues of CAP for the interactions between CAP and cAMP and between CAP and DNA.

  1. Brownian dynamics simulations of a flexible polymer chain which includes continuous resistance and multibody hydrodynamic interactions

    Science.gov (United States)

    Butler, Jason E.; Shaqfeh, Eric S. G.

    2005-01-01

    Using methods adapted from the simulation of suspension dynamics, we have developed a Brownian dynamics algorithm with multibody hydrodynamic interactions for simulating the dynamics of polymer molecules. The polymer molecule is modeled as a chain composed of a series of inextensible, rigid rods with constraints at each joint to ensure continuity of the chain. The linear and rotational velocities of each segment of the polymer chain are described by the slender-body theory of Batchelor [J. Fluid Mech. 44, 419 (1970)]. To include hydrodynamic interactions between the segments of the chain, the line distribution of forces on each segment is approximated by making a Legendre polynomial expansion of the disturbance velocity on the segment, where the first two terms of the expansion are retained in the calculation. Thus, the resulting linear force distribution is specified by a center of mass force, couple, and stresslet on each segment. This method for calculating the hydrodynamic interactions has been successfully used to simulate the dynamics of noncolloidal suspensions of rigid fibers [O. G. Harlen, R. R. Sundararajakumar, and D. L. Koch, J. Fluid Mech. 388, 355 (1999); J. E. Butler and E. S. G. Shaqfeh, J. Fluid Mech. 468, 204 (2002)]. The longest relaxation time and center of mass diffusivity are among the quantities calculated with the simulation technique. Comparisons are made for different levels of approximation of the hydrodynamic interactions, including multibody interactions, two-body interactions, and the "freely draining" case with no interactions. For the short polymer chains studied in this paper, the results indicate a difference in the apparent scaling of diffusivity with polymer length for the multibody versus two-body level of approximation for the hydrodynamic interactions.

  2. Exploring Biomolecular Interactions Through Single-Molecule Force Spectroscopy and Computational Simulation

    OpenAIRE

    Yang, Darren

    2016-01-01

    Molecular interactions between cellular components such as proteins and nucleic acids govern the fundamental processes of living systems. Technological advancements in the past decade have allowed the characterization of these molecular interactions at the single-molecule level with high temporal and spatial resolution. Simultaneously, progress in computer simulation has enabled theoretical research at the atomistic level, assisting in the interpretation of experimental results. This thesi...

  3. Nonlinear soil-structure interaction calculations simulating the SIMQUAKE experiment using STEALTH 2D

    Science.gov (United States)

    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.

  4. Interactive simulations for promoting transdisciplinary understanding: a case study of the Western Cape fisheries, South Africa

    Directory of Open Access Journals (Sweden)

    Cecile Proches

    2012-07-01

    Full Text Available Simulations have proven beneficial in enabling participants from various backgrounds to meaningfully engage in learning from experience. The aim of this paper is to investigate how interactive simulations can play a role in navigating the changes faced in a multi- stakeholder setting, characterised by users dependent on marine resources and an authorising institution. Relevant literature in the areas of simulation and gaming, change management, systems thinking, and complexity theory was examined. A qualitative research approach and purposive sampling were employed. Interviews were first conducted with diverse stakeholders in the Western Cape fisheries of South Africa to determine the issues. A simulation was thereafter designed. The main findings from this study indicate that simulation use illustrates how the various stakeholders in a system interact, and how their actions and decisions influence each other. The simulation may be used in other areas of natural resource management, as well as in other kinds of multi- stakeholder scenarios. Keywords: Simulation and gaming, Change management, Fisheries, Multi-stakeholder scenarios, Systems thinking, Complexity theory Disciplines: Conflict Resolution, Leadership Studies, Management Studies, Natural Resource Management

  5. Interactive Web-based Floodplain Simulation System for Realistic Experiments of Flooding and Flood Damage

    Science.gov (United States)

    Demir, I.

    2013-12-01

    Recent developments in web technologies make it easy to manage and visualize large data sets with general public. Novel visualization techniques and dynamic user interfaces allow users to create realistic environments, and interact with data to gain insight from simulations and environmental observations. The floodplain simulation system is a web-based 3D interactive flood simulation environment to create real world flooding scenarios. The simulation systems provides a visually striking platform with realistic terrain information, and water simulation. Students can create and modify predefined scenarios, control environmental parameters, and evaluate flood mitigation techniques. The web-based simulation system provides an environment to children and adults learn about the flooding, flood damage, and effects of development and human activity in the floodplain. The system provides various scenarios customized to fit the age and education level of the users. This presentation provides an overview of the web-based flood simulation system, and demonstrates the capabilities of the system for various flooding and land use scenarios.

  6. Microsurgery Simulator of Cerebral Aneurysm Clipping with Interactive Cerebral Deformation Featuring a Virtual Arachnoid.

    Science.gov (United States)

    Shono, Naoyuki; Kin, Taichi; Nomura, Seiji; Miyawaki, Satoru; Saito, Toki; Imai, Hideaki; Nakatomi, Hirofumi; Oyama, Hiroshi; Saito, Nobuhito

    2018-05-01

    A virtual reality simulator for aneurysmal clipping surgery is an attractive research target for neurosurgeons. Brain deformation is one of the most important functionalities necessary for an accurate clipping simulator and is vastly affected by the status of the supporting tissue, such as the arachnoid membrane. However, no virtual reality simulator implementing the supporting tissue of the brain has yet been developed. To develop a virtual reality clipping simulator possessing interactive brain deforming capability closely dependent on arachnoid dissection and apply it to clinical cases. Three-dimensional computer graphics models of cerebral tissue and surrounding structures were extracted from medical images. We developed a new method for modifiable cerebral tissue complex deformation by incorporating a nonmedical image-derived virtual arachnoid/trabecula in a process called multitissue integrated interactive deformation (MTIID). MTIID made it possible for cerebral tissue complexes to selectively deform at the site of dissection. Simulations for 8 cases of actual clipping surgery were performed before surgery and evaluated for their usefulness in surgical approach planning. Preoperatively, each operative field was precisely reproduced and visualized with the virtual brain retraction defined by users. The clear visualization of the optimal approach to treating the aneurysm via an appropriate arachnoid incision was possible with MTIID. A virtual clipping simulator mainly focusing on supporting tissues and less on physical properties seemed to be useful in the surgical simulation of cerebral aneurysm clipping. To our knowledge, this article is the first to report brain deformation based on supporting tissues.

  7. A modeling study of the thermosphere-ionosphere interactions during the boreal winter and spring 2015-2016: Tidal and planetary-scale waves effect on the ionospheric structure.

    Science.gov (United States)

    Sassi, F.; McDonald, S. E.; McCormack, J. P.; Tate, J.; Liu, H.; Kuhl, D.

    2017-12-01

    The 2015-2016 boreal winter and spring is a dynamically very interesting time in the lower atmosphere: a minor high latitude stratospheric warming occurred in February 2016; an interrupted descent of the QBO was found in the tropical stratosphere; and a large warm ENSO took place in the tropical Pacific Ocean. The stratospheric warming, the QBO and ENSO are known to affect in different ways the meteorology of the upper atmosphere in different ways: low latitude solar tides and high latitude planetary-scale waves have potentially important implications on the structure of the ionosphere. In this study, we use global atmospheric analyses from a high-altitude version of the High-Altitude Navy Global Environmental Model (HA-NAVGEM) to constrain the meteorology of numerical simulations of the Specified Dynamics Whole Atmosphere Community Climate Model, extended version (SD-WACCM-X). We describe the large-scale behavior of tropical tides and mid-latitude planetary waves that emerge in the lower thermosphere. The effect on the ionosphere is captured by numerical simulations of the Navy Highly Integrated Thermosphere Ionosphere Demonstration System (Navy-HITIDES) that uses the meteorology generated by SD-WACCM-X to drive ionospheric simulations during this time period. We will analyze the impact of various dynamical fields on the zonal behavior of the ionosphere by selectively filtering the relevant dynamical modes.

  8. QuVis interactive simulations: tools to support quantum mechanics instruction

    Science.gov (United States)

    Kohnle, Antje

    2015-04-01

    Quantum mechanics holds a fascination for many students, but its mathematical complexity and counterintuitive results can present major barriers. The QuVis Quantum Mechanics Visualization Project (www.st-andrews.ac.uk/physics/quvis) aims to overcome these issues through the development and evaluation of interactive simulations with accompanying activities for the learning and teaching of quantum mechanics. Over 90 simulations are now available on the QuVis website. One collection of simulations is embedded in the Institute of Physics Quantum Physics website (quantumphysics.iop.org), which consists of freely available resources for an introductory course in quantum mechanics starting from two-level systems. Simulations support model-building by reducing complexity, focusing on fundamental ideas and making the invisible visible. They promote engaged exploration, sense-making and linking of multiple representations, and include high levels of interactivity and direct feedback. Simulations are research-based and evaluation with students informs all stages of the development process. Simulations are iteratively refined using student feedback in individual observation sessions and in-class trials. Evaluation has shown that the simulations can help students learn quantum mechanics concepts at both the introductory and advanced undergraduate level and that students perceive simulations to be beneficial to their learning. Recent activity includes the launch of a new collection of HTML5 simulations that run on both desktop and tablet-based devices and the introduction of a goal and reward structure in simulations through the inclusion of challenges. This presentation will give an overview of the QuVis resources, highlight recent work and outline future plans. QuVis is supported by the UK Institute of Physics, the UK Higher Education Academy and the University of St Andrews.

  9. Atomistic simulations of dislocation-precipitate interactions emphasize importance of cross-slip

    International Nuclear Information System (INIS)

    Singh, C.V.; Mateos, A.J.; Warner, D.H.

    2011-01-01

    This work examines the interaction of screw dislocations with Guinier-Preston (GP) zones using atomistic simulations. Both Orowan looping and cross-slip mechanisms are found to control the interactions. Cross-slip, occurring both at zero and finite temperatures, is found to either significantly reduce or enhance precipitate strengthening, depending upon the orientation of the dislocation-GP zone interaction. The orientation dependence, and its dependence on temperature, provides a micromechanical explanation for the experiments of Muraishi et al. (Philos. Mag. A 82 (2002) 2755).

  10. PyContact: Rapid, Customizable, and Visual Analysis of Noncovalent Interactions in MD Simulations.

    Science.gov (United States)

    Scheurer, Maximilian; Rodenkirch, Peter; Siggel, Marc; Bernardi, Rafael C; Schulten, Klaus; Tajkhorshid, Emad; Rudack, Till

    2018-02-06

    Molecular dynamics (MD) simulations have become ubiquitous in all areas of life sciences. The size and model complexity of MD simulations are rapidly growing along with increasing computing power and improved algorithms. This growth has led to the production of a large amount of simulation data that need to be filtered for relevant information to address specific biomedical and biochemical questions. One of the most relevant molecular properties that can be investigated by all-atom MD simulations is the time-dependent evolution of the complex noncovalent interaction networks governing such fundamental aspects as molecular recognition, binding strength, and mechanical and structural stability. Extracting, evaluating, and visualizing noncovalent interactions is a key task in the daily work of structural biologists. We have developed PyContact, an easy-to-use, highly flexible, and intuitive graphical user interface-based application, designed to provide a toolkit to investigate biomolecular interactions in MD trajectories. PyContact is designed to facilitate this task by enabling identification of relevant noncovalent interactions in a comprehensible manner. The implementation of PyContact as a standalone application enables rapid analysis and data visualization without any additional programming requirements, and also preserves full in-program customization and extension capabilities for advanced users. The statistical analysis representation is interactively combined with full mapping of the results on the molecular system through the synergistic connection between PyContact and VMD. We showcase the capabilities and scientific significance of PyContact by analyzing and visualizing in great detail the noncovalent interactions underlying the ion permeation pathway of the human P2X 3 receptor. As a second application, we examine the protein-protein interaction network of the mechanically ultrastable cohesin-dockering complex. Copyright © 2017 Biophysical Society

  11. Online simulation of classical inorganic analysis - interactive, self instructive simulations give more lab-time

    DEFF Research Database (Denmark)

    Josephsen, Jens

    2005-01-01

    Laboratory exercises, investigations, and experiments are invariably included in university chemistry teaching. The learning of empirical facts, chemical procedures and methods in chemistry depends heavily on the experience, which may be obtained from such teaching activities [1]. Experimental work...... in teaching is, however, both expensive and time consuming, and should therefor effectively benefit from the allotted student time, money, and staff time. If the instructions are too ambitious regarding what the students can manage to do and are overloaded with information [2,3] it may result in the students...... (and in university programmes it often isn’t), but rather to give them experience with chemicals and methods, a computer-based laboratory simulation may function as a cheap and fast extension of student lab time. Virtual investigations seem to be a promising kind of tool [6,7,8] for several reasons...

  12. Molecular dynamics simulations of interfacial interactions between small nanoparticles during diffusion-limited aggregation

    International Nuclear Information System (INIS)

    Lu, Jing; Liu, Dongmei; Yang, Xiaonan; Zhao, Ying; Liu, Haixing; Tang, Huan; Cui, Fuyi

    2015-01-01

    Graphical abstract: - Highlights: • Diffusion-limited aggregation is analyzed using molecular dynamic simulations. • The aggregation processand aggregate structure vary with particle size. • Particle-particle interaction and surface diffusion result in direct bonding. • Water-mediated interaction is responsible for the separation betweennanoparticles. - Abstract: Due to the limitations of experimental methods at the atomic level, research on the aggregation of small nanoparticles (D < 5 nm) in aqueous solutions is quite rare. The aggregation of small nanoparticles in aqueous solutions is very different than that of normal sized nanoparticles. The interfacial interactions play a dominant role in the aggregation of small nanoparticles. In this paper, molecular dynamics simulations, which can explore the microscopic behavior of nanoparticles during the diffusion-limited aggregation at an atomic level, were employed to reveal the aggregation mechanism of small nanoparticles in aqueous solutions. First, the aggregation processes and aggregate structure were depicted. Second, the particle–particle interaction and surface diffusion of nanoparticles during aggregation were investigated. Third, the water-mediated interactions during aggregation were ascertained. The results indicate that the aggregation of nanoparticle in aqueous solutions is affected by particle size. The strong particle–particle interaction and high surface diffusion result in the formation of particle–particle bonds of 2 nm TiO 2 nanoparticles, and the water-mediated interaction plays an important role in the aggregation process of 3 and 4 nm TiO 2 nanoparticles.

  13. Modelling and simulation of particle-particle interaction in a magnetophoretic bio-separation chip

    Science.gov (United States)

    Alam, Manjurul; Golozar, Matin; Darabi, Jeff

    2018-04-01

    A Lagrangian particle trajectory model is developed to predict the interaction between cell-bead particle complexes and to track their trajectories in a magnetophoretic bio-separation chip. Magnetic flux gradients are simulated in the OpenFOAM CFD software and imported into MATLAB to obtain the trapping lengths and trajectories of the particles. A connector vector is introduced to calculate the interaction force between cell-bead complexes as they flow through a microfluidic device. The interaction force calculations are performed for cases where the connector vector is parallel, perpendicular, and at an angle of 45° with the applied magnetic field. The trajectories of the particles are simulated by solving a system of eight ordinary differential equations using a fourth order Runge-Kutta method. The model is then used to study the effects of geometric positions and angles of the connector vector between the particles as well as the cell size, number of beads per cell, and flow rate on the interaction force and trajectories of the particles. The results show that the interaction forces may be attractive or repulsive, depending on the orientation of the connector vector distance between the particle complexes and the applied magnetic field. When the interaction force is attractive, the particles are observed to merge and trap sooner than a single particle, whereas a repulsive interaction force has little or no effect on the trapping length.

  14. Simulation of aerosol flow interaction with a solid body on molecular level

    Science.gov (United States)

    Amelyushkin, Ivan A.; Stasenko, Albert L.

    2018-05-01

    Physico-mathematical models and numerical algorithm of two-phase flow interaction with a solid body are developed. Results of droplet motion and its impingement upon a rough surface in real gas boundary layer simulation on the molecular level obtained via molecular dynamics technique are presented.

  15. Getting the ion-protein interactions right in molecular dynamics simulations

    Czech Academy of Sciences Publication Activity Database

    Duboué-Dijon, Elise; Mason, Philip E.; Jungwirth, Pavel

    2017-01-01

    Roč. 46, Suppl 1 (2017), S66 ISSN 0175-7571. [IUPAB congress /19./ and EBSA congress /11./. 16.07.2017-20.07.2017, Edinburgh] Institutional support: RVO:61388963 Keywords : ion-protein interaction * molecular dynamics simulations * neutron scattering * insulin Subject RIV: BO - Biophysics

  16. Female rock sparrows (Petronia petronia), not males, respond differently to simulations of different courtship interaction outcomes

    DEFF Research Database (Denmark)

    Matessi, Giuliano; Peake, Tom M.; McGregor, Peter K.

    2007-01-01

    individuals of both sexes have access to a range of mating strategies. We tested whether rock sparrows (Petronia petronia) behave differently after hearing playbacks of vocal interactions simulating a successful courtship as opposed to playback of an unsuccessful courtship. We found no support for our...

  17. An interactive visualisation tool applied to the simulation of glass pressing

    NARCIS (Netherlands)

    Laevsky, K.; Telea, A.; Mattheij, R.M.M.

    2001-01-01

    An interactive numerical simulation approach to the process of glass pressing is presented. Glass is modelled as a strongly viscous Newtonian fluid whose deformation under pressure is described by a Stokes equation. Modelling the evolution of the glass free boundary in time poses a particular

  18. DataSpaces: An Interaction and Coordination Framework for Coupled Simulation Workflows

    International Nuclear Information System (INIS)

    Docan, Ciprian; Klasky, Scott A.; Parashar, Manish

    2010-01-01

    Emerging high-performance distributed computing environments are enabling new end-to-end formulations in science and engineering that involve multiple interacting processes and data-intensive application workflows. For example, current fusion simulation efforts are exploring coupled models and codes that simultaneously simulate separate application processes, such as the core and the edge turbulence, and run on different high performance computing resources. These components need to interact, at runtime, with each other and with services for data monitoring, data analysis and visualization, and data archiving. As a result, they require efficient support for dynamic and flexible couplings and interactions, which remains a challenge. This paper presents Data-Spaces, a flexible interaction and coordination substrate that addresses this challenge. DataSpaces essentially implements a semantically specialized virtual shared space abstraction that can be associatively accessed by all components and services in the application workflow. It enables live data to be extracted from running simulation components, indexes this data online, and then allows it to be monitored, queried and accessed by other components and services via the space using semantically meaningful operators. The underlying data transport is asynchronous, low-overhead and largely memory-to-memory. The design, implementation, and experimental evaluation of DataSpaces using a coupled fusion simulation workflow is presented.

  19. Multiscale Molecular Dynamics Simulations of Beta-Amyloid Interactions with Neurons

    Science.gov (United States)

    Qiu, Liming; Vaughn, Mark; Cheng, Kelvin

    2012-10-01

    Early events of human beta-amyloid protein interactions with cholesterol-containing membranes are critical to understanding the pathogenesis of Alzheimer's disease (AD) and to exploring new therapeutic interventions of AD. Atomistic molecular dynamics (AMD) simulations have been extensively used to study the protein-lipid interaction at high atomic resolutions. However, traditional MD simulations are not efficient in sampling the phase space of complex lipid/protein systems with rugged free energy landscapes. Meanwhile, coarse-grained MD (CGD) simulations are efficient in the phase space sampling but suffered from low spatial resolutions and from the fact that the energy landscapes are not identical to those of the AMD. Here, a multiscale approach was employed to simulate the protein-lipid interactions of beta-amyloid upon its release from proteolysis residing in the neuronal membranes. We utilized a forward (AMD to CGD) and reverse (CGD-AMD) strategy to explore new transmembrane and surface protein configuration and evaluate the stabilization mechanisms by measuring the residue-specific protein-lipid or protein conformations. The detailed molecular interactions revealed in this multiscale MD approach will provide new insights into understanding the early molecular events leading to the pathogenesis of AD.

  20. THE SIMULATED SOCIAL-INTERACTION TEST - A PSYCHOMETRIC EVALUATION WITH DUTCH SOCIAL PHOBIC PATIENTS

    NARCIS (Netherlands)

    MERSCH, PPA; BREUKERS, P; EMMELKAMP, PMG

    1992-01-01

    The Simulated Social Interaction Test (SSIT) was translated and adjusted for use on a population of Dutch males and females. Seventy-four social phobic patients were assessed with the SSIT, a conversation test, and an interview with an independent observer. Results show that the SSIT is a relatively

  1. Investigation of wake interaction using full-scale lidar measurements and large eddy simulation

    DEFF Research Database (Denmark)

    Machefaux, Ewan; Larsen, Gunner Chr.; Troldborg, Niels

    2016-01-01

    dynamics flow solver, using large eddy simulation and fully turbulent inflow. The rotors are modelled using the actuator disc technique. A mutual validation of the computational fluid dynamics model with the measurements is conducted for a selected dataset, where wake interaction occurs. This validation...

  2. Teachers' Beliefs and Their Intention to Use Interactive Simulations in Their Classrooms

    Science.gov (United States)

    Kriek, Jeanne; Stols, Gerrit

    2010-01-01

    In this pilot study, we sought to examine the influence of the beliefs of Grade 10 to 12 physical science teachers on their intended and actual usage of interactive simulations (Physics Education Technology, or PhET) in their classrooms. A combination of the Theory of Planned Behaviour, the Technology Acceptance Model and the Innovation Diffusion…

  3. Comparison of DNDC and RZWQM2 for simulating hydrology and nitrogen dynamics in a corn-soybean system with a winter cover crop

    Science.gov (United States)

    Desjardins, R.; Smith, W.; Qi, Z.; Grant, B.; VanderZaag, A.

    2017-12-01

    Biophysical models are needed for assessing science-based mitigation options to improve the efficiency and sustainability of agricultural cropping systems. In order to account for trade-offs between environmental indicators such as GHG emissions, soil C change, and water quality it is important that models can encapsulate the complex array of interrelated biogeochemical processes controlling water, nutrient and energy flows in the agroecosystem. The Denitrification Decomposition (DNDC) model is one of the most widely used process-based models, and is arguably the most sophisticated for estimating GHG emissions and soil C&N cycling, however, the model simulates only simple cascade water flow. The purpose of this study was to compare the performance of DNDC to a comprehensive water flow model, the Root Zone Water Quality Model (RZWQM2), to determine which processes in DNDC may be limiting and recommend improvements. Both models were calibrated and validated for simulating crop biomass, soil hydrology, and nitrogen loss to tile drains using detailed observations from a corn-soybean rotation in Iowa, with and without cover crops. Results indicated that crop yields, biomass and the annual estimation of nitrogen and water loss to tiles drains were well simulated by both models (NSE > 0.6 in all cases); however, RZWQM2 performed much better for simulating soil water content, and the dynamics of daily water flow (DNDC: NSE -0.32 to 0.28; RZWQM2: NSE 0.34 to 0.70) to tile drains. DNDC overestimated soil water content near the soil surface and underestimated it deeper in the profile which was presumably caused by the lack of a root distribution algorithm, the inability to simulate a heterogeneous profile and lack of a water table. We recommend these improvements along with the inclusion of enhanced water flow and a mechanistic tile drainage sub-model. The accurate temporal simulation of water and N strongly impacts several biogeochemical processes.

  4. Interactive knowledge discovery from marketing questionnarie using simulated breeding and inductive learning methods

    Energy Technology Data Exchange (ETDEWEB)

    Terano, Takao [Univ. of Tsukuba, Tokyo (Japan); Ishino, Yoko [Univ. of Tokyo (Japan)

    1996-12-31

    This paper describes a novel method to acquire efficient decision rules from questionnaire data using both simulated breeding and inductive learning techniques. The basic ideas of the method are that simulated breeding is used to get the effective features from the questionnaire data and that inductive learning is used to acquire simple decision rules from the data. The simulated breeding is one of the Genetic Algorithm (GA) based techniques to subjectively or interactively evaluate the qualities of offspring generated by genetic operations. In this paper, we show a basic interactive version of the method and two variations: the one with semi-automated GA phases and the one with the relatively evaluation phase via the Analytic Hierarchy Process (AHP). The proposed method has been qualitatively and quantitatively validated by a case study on consumer product questionnaire data.

  5. Modeling and Simulation for Exploring Human-Robot Team Interaction Requirements

    Energy Technology Data Exchange (ETDEWEB)

    Dudenhoeffer, Donald Dean; Bruemmer, David Jonathon; Davis, Midge Lee

    2001-12-01

    Small-sized and micro-robots will soon be available for deployment in large-scale forces. Consequently, the ability of a human operator to coordinate and interact with largescale robotic forces is of great interest. This paper describes the ways in which modeling and simulation have been used to explore new possibilities for human-robot interaction. The paper also discusses how these explorations have fed implementation of a unified set of command and control concepts for robotic force deployment. Modeling and simulation can play a major role in fielding robot teams in actual missions. While live testing is preferred, limitations in terms of technology, cost, and time often prohibit extensive experimentation with physical multi-robot systems. Simulation provides insight, focuses efforts, eliminates large areas of the possible solution space, and increases the quality of actual testing.

  6. Numerical Simulation of Interactions between Corrosion Pits on Stainless Steel under Loading Conditions

    International Nuclear Information System (INIS)

    Wang, Haitao; Han, En-Hou

    2017-01-01

    The interactions between corrosion pits on stainless steel under loading conditions are studied by using a cellular automata model coupled with finite element method at a mesoscopic scale. The cellular automata model focuses on a metal/film/electrolyte system, including anodic dissolution, passivation, diffusion of hydrogen ions and salt film hydrolysis. The Chopard block algorithm is used to improve the diffusion simulation efficiency. The finite element method is used to calculate the stress concentration on the pit surface during pit growth, and the effect of local stress and strain on anodic current is obtained by using the Gutman model, which is used as the boundary conditions of the cellular automata model. The transient current characteristics of the interactions between corrosion pits under different simulation factors including the breakdown of the passive film at the pit mouth and the diffusion of hydrogen ions are analyzed. The analysis of the pit stability product shows that the simulation results are close to the experimental conclusions.

  7. Numerical Simulation of Interactions between Corrosion Pits on Stainless Steel under Loading Conditions

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Haitao; Han, En-Hou [Chinese Academy of Sciences, Shenyang (China)

    2017-04-15

    The interactions between corrosion pits on stainless steel under loading conditions are studied by using a cellular automata model coupled with finite element method at a mesoscopic scale. The cellular automata model focuses on a metal/film/electrolyte system, including anodic dissolution, passivation, diffusion of hydrogen ions and salt film hydrolysis. The Chopard block algorithm is used to improve the diffusion simulation efficiency. The finite element method is used to calculate the stress concentration on the pit surface during pit growth, and the effect of local stress and strain on anodic current is obtained by using the Gutman model, which is used as the boundary conditions of the cellular automata model. The transient current characteristics of the interactions between corrosion pits under different simulation factors including the breakdown of the passive film at the pit mouth and the diffusion of hydrogen ions are analyzed. The analysis of the pit stability product shows that the simulation results are close to the experimental conclusions.

  8. The "resident's dilemma"? Values and strategies of medical residents for education interactions: a cellular automata simulation.

    Science.gov (United States)

    Heckerling, P S; Gerber, B S; Weiner, S J

    2006-01-01

    Medical residents engage in formal and informal education interactions with fellow residents during the working day, and can choose whether to spend time and effort on such interactions. Time and effort spent on such interactions can bring learning and personal satisfaction to residents, but may also delay completion of clinical work. Using hypothetical cases, we assessed the values and strategies of internal medicine residents at one hospital for both cooperative and non-cooperative education interactions with fellow residents. We then used these data and cellular automata models of two-person games to simulate repeated interactions between residents, and to determine which strategies resulted in greatest accrued value. We conducted sensitivity analyses on several model parameters, to test the robustness of dominant strategies to model assumptions. Twenty-nine of the 57 residents (50.9%) valued cooperation more than non-cooperation no matter what the other resident did during the current interaction. Similarly, thirty-six residents (63.2%) endorsed an unconditional always-cooperate strategy no matter what the other resident had done during their previous interaction. In simulations, an always-cooperate strategy accrued more value (776.42 value units) than an aggregate of strategies containing non-cooperation components (675.0 value units, p = 0.052). Only when the probability of strategy errors reached 50%, or when values were re-ordered to match those of a Prisoner's Dilemma, did non-cooperation-based strategies accrue the most value. Cooperation-based values and strategies were most frequent among our residents, and dominated in simulations of repeated education interactions between them.

  9. Simulations of collisions between N-body classical systems in interaction; Simulations de collisions entre systemes classiques a n-corps en interaction

    Energy Technology Data Exchange (ETDEWEB)

    Morisseau, Francois [Laboratoire de Physique Corpusculaire de CAEN, ENSICAEN, Universite de Caen Basse-Normandie, UFR des Sciences, 6 bd Marechal Juin, 14050 Caen Cedex (France)

    2006-05-15

    The Classical N-body Dynamics (CNBD) is dedicated to the simulation of collisions between classical systems. The 2-body interaction used here has the properties of the Van der Waals potential and depends on just a few parameters. This work has two main goals. First, some theoretical approaches assume that the dynamical stage of the collisions plays an important role. Moreover, colliding nuclei are supposed to present a 1. order liquid-gas phase transition. Several signals have been introduced to show this transition. We have searched for two of them: the bimodality of the mass asymmetry and negative heat capacity. We have found them and we give an explanation of their presence in our calculations. Second, we have improved the interaction by adding a Coulomb like potential and by taking into account the stronger proton-neutron interaction in nuclei. Then we have figured out the relations that exist between the parameters of the 2-body interaction and the properties of the systems. These studies allow us to fit the properties of the classical systems to those of the nuclei. In this manuscript the first results of this fit are shown. (author)

  10. A simulation study on estimating biomarker-treatment interaction effects in randomized trials with prognostic variables.

    Science.gov (United States)

    Haller, Bernhard; Ulm, Kurt

    2018-02-20

    To individualize treatment decisions based on patient characteristics, identification of an interaction between a biomarker and treatment is necessary. Often such potential interactions are analysed using data from randomized clinical trials intended for comparison of two treatments. Tests of interactions are often lacking statistical power and we investigated if and how a consideration of further prognostic variables can improve power and decrease the bias of estimated biomarker-treatment interactions in randomized clinical trials with time-to-event outcomes. A simulation study was performed to assess how prognostic factors affect the estimate of the biomarker-treatment interaction for a time-to-event outcome, when different approaches, like ignoring other prognostic factors, including all available covariates or using variable selection strategies, are applied. Different scenarios regarding the proportion of censored observations, the correlation structure between the covariate of interest and further potential prognostic variables, and the strength of the interaction were considered. The simulation study revealed that in a regression model for estimating a biomarker-treatment interaction, the probability of detecting a biomarker-treatment interaction can be increased by including prognostic variables that are associated with the outcome, and that the interaction estimate is biased when relevant prognostic variables are not considered. However, the probability of a false-positive finding increases if too many potential predictors are included or if variable selection is performed inadequately. We recommend undertaking an adequate literature search before data analysis to derive information about potential prognostic variables and to gain power for detecting true interaction effects and pre-specifying analyses to avoid selective reporting and increased false-positive rates.

  11. Warmed Winter Water Temperatures Alter Reproduction in Two Fish Species.

    Science.gov (United States)

    Firkus, Tyler; Rahel, Frank J; Bergman, Harold L; Cherrington, Brian D

    2018-02-01

    We examined the spawning success of Fathead Minnows (Pimephales promelas) and Johnny Darters (Etheostoma nigrum) exposed to elevated winter water temperatures typical of streams characterized by anthropogenic thermal inputs. When Fathead Minnows were exposed to temperature treatments of 12, 16, or 20 °C during the winter, spawning occurred at 16 and 20 °C but not 12 °C. Eggs were deposited over 9 weeks before winter spawning ceased. Fathead Minnows from the three winter temperature treatments were then exposed to a simulated spring transition. Spawning occurred at all three temperature treatments during the spring, but fish from the 16° and 20 °C treatment had delayed egg production indicating a latent effect of warm winter temperatures on spring spawning. mRNA analysis of the egg yolk protein vitellogenin showed elevated expression in female Fathead Minnows at 16 and 20 °C during winter spawning that decreased after winter spawning ceased, whereas Fathead Minnows at 12 °C maintained comparatively low expression during winter. Johnny Darters were exposed to 4 °C to represent winter temperatures in the absence of thermal inputs, and 12, 16, and 20 °C to represent varying degrees of winter thermal pollution. Johnny Darters spawned during winter at 12, 16, and 20 °C but not at 4 °C. Johnny Darters at 4 °C subsequently spawned following a simulated spring period while those at 12, 16, and 20 °C did not. Our results indicate elevated winter water temperatures common in effluent-dominated streams can promote out-of-season spawning and that vitellogenin expression is a useful indicator of spawning readiness for fish exposed to elevated winter temperatures.

  12. Warmed Winter Water Temperatures Alter Reproduction in Two Fish Species

    Science.gov (United States)

    Firkus, Tyler; Rahel, Frank J.; Bergman, Harold L.; Cherrington, Brian D.

    2018-02-01

    We examined the spawning success of Fathead Minnows ( Pimephales promelas) and Johnny Darters ( Etheostoma nigrum) exposed to elevated winter water temperatures typical of streams characterized by anthropogenic thermal inputs. When Fathead Minnows were exposed to temperature treatments of 12, 16, or 20 °C during the winter, spawning occurred at 16 and 20 °C but not 12 °C. Eggs were deposited over 9 weeks before winter spawning ceased. Fathead Minnows from the three winter temperature treatments were then exposed to a simulated spring transition. Spawning occurred at all three temperature treatments during the spring, but fish from the 16° and 20 °C treatment had delayed egg production indicating a latent effect of warm winter temperatures on spring spawning. mRNA analysis of the egg yolk protein vitellogenin showed elevated expression in female Fathead Minnows at 16 and 20 °C during winter spawning that decreased after winter spawning ceased, whereas Fathead Minnows at 12 °C maintained comparatively low expression during winter. Johnny Darters were exposed to 4 °C to represent winter temperatures in the absence of thermal inputs, and 12, 16, and 20 °C to represent varying degrees of winter thermal pollution. Johnny Darters spawned during winter at 12, 16, and 20 °C but not at 4 °C. Johnny Darters at 4 °C subsequently spawned following a simulated spring period while those at 12, 16, and 20 °C did not. Our results indicate elevated winter water temperatures common in effluent-dominated streams can promote out-of-season spawning and that vitellogenin expression is a useful indicator of spawning readiness for fish exposed to elevated winter temperatures.

  13. Molecular dynamics simulations of matrix assisted laser desorption ionization: Matrix-analyte interactions

    International Nuclear Information System (INIS)

    Nangia, Shivangi; Garrison, Barbara J.

    2011-01-01

    There is synergy between matrix assisted laser desorption ionization (MALDI) experiments and molecular dynamics (MD) simulations. To understand analyte ejection from the matrix, MD simulations have been employed. Prior calculations show that the ejected analyte molecules remain solvated by the matrix molecules in the ablated plume. In contrast, the experimental data show free analyte ions. The main idea of this work is that analyte molecule ejection may depend on the microscopic details of analyte interaction with the matrix. Intermolecular matrix-analyte interactions have been studied by focusing on 2,5-dihydroxybenzoic acid (DHB; matrix) and amino acids (AA; analyte) using Chemistry at HARvard Molecular Mechanics (CHARMM) force field. A series of AA molecules have been studied to analyze the DHB-AA interaction. A relative scale of AA molecule affinity towards DHB has been developed.

  14. The nuclear winter

    International Nuclear Information System (INIS)

    Velikhow, Y.P.

    1986-01-01

    Nuclear winter is an example of possible secondary effects, and if we speak of secondary we are thinking of small-scale second-order effects, but a nuclear winter is not a second-order effect. If you calculate the amount of heat produced by a nuclear explosion, it is a very small amount which does not have any chance of changing the Earth's climate, but a nuclear explosion drives or stars some new mechanism - the mechanism of nuclear winter - after 100 megatons of dust are transferred to the upper atmosphere. Another example of such amplification is radioactive fall-out, especially long-life radioactive fall-out after the possible elimination of the nuclear power industry, nuclear storage and distribution of storage waste around the globe. This is a very powerful amplification mechanism

  15. Neurosurgery simulation using non-linear finite element modeling and haptic interaction

    Science.gov (United States)

    Lee, Huai-Ping; Audette, Michel; Joldes, Grand R.; Enquobahrie, Andinet

    2012-02-01

    Real-time surgical simulation is becoming an important component of surgical training. To meet the realtime requirement, however, the accuracy of the biomechancial modeling of soft tissue is often compromised due to computing resource constraints. Furthermore, haptic integration presents an additional challenge with its requirement for a high update rate. As a result, most real-time surgical simulation systems employ a linear elasticity model, simplified numerical methods such as the boundary element method or spring-particle systems, and coarse volumetric meshes. However, these systems are not clinically realistic. We present here an ongoing work aimed at developing an efficient and physically realistic neurosurgery simulator using a non-linear finite element method (FEM) with haptic interaction. Real-time finite element analysis is achieved by utilizing the total Lagrangian explicit dynamic (TLED) formulation and GPU acceleration of per-node and per-element operations. We employ a virtual coupling method for separating deformable body simulation and collision detection from haptic rendering, which needs to be updated at a much higher rate than the visual simulation. The system provides accurate biomechancial modeling of soft tissue while retaining a real-time performance with haptic interaction. However, our experiments showed that the stability of the simulator depends heavily on the material property of the tissue and the speed of colliding objects. Hence, additional efforts including dynamic relaxation are required to improve the stability of the system.

  16. Interactive real-time nuclear plant simulations on a UNIX based supercomputer

    International Nuclear Information System (INIS)

    Behling, S.R.

    1990-01-01

    Interactive real-time nuclear plant simulations are critically important to train nuclear power plant engineers and operators. In addition, real-time simulations can be used to test the validity and timing of plant technical specifications and operational procedures. To accurately and confidently simulate a nuclear power plant transient in real-time, sufficient computer resources must be available. Since some important transients cannot be simulated using preprogrammed responses or non-physical models, commonly used simulation techniques may not be adequate. However, the power of a supercomputer allows one to accurately calculate the behavior of nuclear power plants even during very complex transients. Many of these transients can be calculated in real-time or quicker on the fastest supercomputers. The concept of running interactive real-time nuclear power plant transients on a supercomputer has been tested. This paper describes the architecture of the simulation program, the techniques used to establish real-time synchronization, and other issues related to the use of supercomputers in a new and potentially very important area. (author)

  17. A unified framework for spiking and gap-junction interactions in distributed neuronal network simulations

    Directory of Open Access Journals (Sweden)

    Jan eHahne

    2015-09-01

    Full Text Available Contemporary simulators for networks of point and few-compartment model neurons come with a plethora of ready-to-use neuron and synapse models and support complex network topologies. Recent technological advancements have broadened the spectrum of application further to the efficient simulation of brain-scale networks on supercomputers. In distributed network simulations the amount of spike data that accrues per millisecond and process is typically low, such that a common optimization strategy is to communicate spikes at relatively long intervals, where the upper limit is given by the shortest synaptic transmission delay in the network. This approach is well-suited for simulations that employ only chemical synapses but it has so far impeded the incorporation of gap-junction models, which require instantaneous neuronal interactions. Here, we present a numerical algorithm based on a waveform-relaxation technique which allows for network simulations with gap junctions in a way that is compatible with the delayed communication strategy. Using a reference implementation in the NEST simulator, we demonstrate that the algorithm and the required data structures can be smoothly integrated with existing code such that they complement the infrastructure for spiking connections. To show that the unified framework for gap-junction and spiking interactions achieves high performance and delivers high accuracy...

  18. Euler-Lagrange Simulations of Shock Wave-Particle Cloud Interaction

    Science.gov (United States)

    Koneru, Rahul; Rollin, Bertrand; Ouellet, Frederick; Park, Chanyoung; Balachandar, S.

    2017-11-01

    Numerical experiments of shock interacting with an evolving and fixed cloud of particles are performed. In these simulations we use Eulerian-Lagrangian approach along with state-of-the-art point-particle force and heat transfer models. As validation, we use Sandia Multiphase Shock Tube experiments and particle-resolved simulations. The particle curtain upon interaction with the shock wave is expected to experience Kelvin-Helmholtz (KH) and Richtmyer-Meshkov (RM) instabilities. In the simulations evolving the particle cloud, the initial volume fraction profile matches with that of Sandia Multiphase Shock Tube experiments, and the shock Mach number is limited to M =1.66. Measurements of particle dispersion are made at different initial volume fractions. A detailed analysis of the influence of initial conditions on the evolution of the particle cloudis presented. The early time behavior of the models is studied in the fixed bed simulations at varying volume fractions and shock Mach numbers.The mean gas quantities are measured in the context of 1-way and 2-way coupled simulations. This work was supported by the U.S. Department of Energy, National Nuclear Security Administration, Advanced Simulation and Computing Program, as a Cooperative Agreement under the Predictive Science Academic Alliance Program, Contract No. DE-NA0002378.

  19. Simulation of the interaction of positively charged beams and electron clouds

    International Nuclear Information System (INIS)

    Markovik, Aleksandar

    2013-01-01

    The incoherent (head-tail) effect on the bunch due to the interaction with electron clouds (e-clouds) leads to a blow up of the transverse beam size in storage rings operating with positively charged beams. Even more the e-cloud effects are considered to be the main limiting factor for high current, high-brightness or high-luminosity operation of future machines. Therefore the simulation of e-cloud phenomena is a highly active field of research. The main focus in this work was set to a development of a tool for simulation of the interaction of relativistic bunches with non-relativistic parasitic charged particles. The result is the Particle-In-Cell Program MOEVE PIC Tracking which can track a 3D bunch under the influence of its own and external electromagnetic fields but first and foremost it simulates the interaction of relativistic positively charged bunches and initially static electrons. In MOEVE PIC Tracking the conducting beam pipe can be modeled with an arbitrary elliptical cross-section to achieve more accurate space charge field computations for both the bunch and the e-cloud. The simulation of the interaction between positron bunches and electron clouds in this work gave a detailed insight of the behavior of both particle species during and after the interaction. Further and ultimate goal of this work was a fast estimation of the beam stability under the influence of e-clouds in the storage ring. The standard approach to simulate the stability of a single bunch is to track the bunch particles through the linear optics of the machine by multiplying the 6D vector of each particle with the transformation matrices describing the lattice. Thereby the action of the e-cloud on the bunch is approximated by a pre-computed wake kick which is applied on one or more points in the lattice. Following the idea of K.Ohmi the wake kick was pre-computed as a two variable function of the bunch part exiting the e-cloud and the subsequent parts of a bunch which receive a

  20. Methods for simulation-based analysis of fluid-structure interaction.

    Energy Technology Data Exchange (ETDEWEB)

    Barone, Matthew Franklin; Payne, Jeffrey L.

    2005-10-01

    Methods for analysis of fluid-structure interaction using high fidelity simulations are critically reviewed. First, a literature review of modern numerical techniques for simulation of aeroelastic phenomena is presented. The review focuses on methods contained within the arbitrary Lagrangian-Eulerian (ALE) framework for coupling computational fluid dynamics codes to computational structural mechanics codes. The review treats mesh movement algorithms, the role of the geometric conservation law, time advancement schemes, wetted surface interface strategies, and some representative applications. The complexity and computational expense of coupled Navier-Stokes/structural dynamics simulations points to the need for reduced order modeling to facilitate parametric analysis. The proper orthogonal decomposition (POD)/Galerkin projection approach for building a reduced order model (ROM) is presented, along with ideas for extension of the methodology to allow construction of ROMs based on data generated from ALE simulations.

  1. Quantified, Interactive Simulation of AMCW ToF Camera Including Multipath Effects.

    Science.gov (United States)

    Bulczak, David; Lambers, Martin; Kolb, Andreas

    2017-12-22

    In the last decade, Time-of-Flight (ToF) range cameras have gained increasing popularity in robotics, automotive industry, and home entertainment. Despite technological developments, ToF cameras still suffer from error sources such as multipath interference or motion artifacts. Thus, simulation of ToF cameras, including these artifacts, is important to improve camera and algorithm development. This paper presents a physically-based, interactive simulation technique for amplitude modulated continuous wave (AMCW) ToF cameras, which, among other error sources, includes single bounce indirect multipath interference based on an enhanced image-space approach. The simulation accounts for physical units down to the charge level accumulated in sensor pixels. Furthermore, we present the first quantified comparison for ToF camera simulators. We present bidirectional reference distribution function (BRDF) measurements for selected, purchasable materials in the near-infrared (NIR) range, craft real and synthetic scenes out of these materials and quantitatively compare the range sensor data.

  2. Simulation of laser interaction with ablative plasma and hydrodynamic behavior of laser supported plasma

    Energy Technology Data Exchange (ETDEWEB)

    Tong Huifeng; Yuan Hong [Institute of Fluid Physics, Chinese Academy of Engineering Physics, P.O. Box 919-101, Mianyang, Sichuan 621900 (China); Tang Zhiping [CAS Key Laboratory for Mechanical Behavior and Design of Materials, Department of Mechanics and Mechanical Engineering, University of Science and Technology of China, Hefei 230026 (China)

    2013-01-28

    When an intense laser beam irradiates on a solid target, ambient air ionizes and becomes plasma, while part of the target rises in temperature, melts, vaporizes, ionizes, and yet becomes plasma. A general Godunov finite difference scheme WENO (Weighted Essentially Non-Oscillatory Scheme) with fifth-order accuracy is used to simulate 2-dimensional axis symmetrical laser-supported plasma flow field in the process of laser ablation. The model of the calculation of ionization degree of plasma and the interaction between laser beam and plasma are considered in the simulation. The numerical simulations obtain the profiles of temperature, density, and velocity at different times which show the evolvement of the ablative plasma. The simulated results show that the laser energy is strongly absorbed by plasma on target surface and that the velocity of laser supported detonation (LSD) wave is half of the ideal LSD value derived from Chapman-Jouguet detonation theory.

  3. PPC - an interactive preprocessor/compiler for the DSNP simulation language

    International Nuclear Information System (INIS)

    Mahannah, J.A.; Schor, A.L.

    1986-01-01

    The PPC preprocessor/compiler was developed for the dynamic simulator for nuclear power plant DSNP simulation language. The goal of PPC is to provide an easy-to-use, interactive programming environment that will aid both the beginner and well-seasoned DSNP programmer. PPC simplifies the steps of the simulation development process for any user. All will benefit from the on-line help facilities, easy manipulation of modules, the elimination of syntax errors, and the general systematic approach. PPC is a very structured and modular program that allows for easy expansion and modification. Written entirely in C, it is fast, compact, and portable. Used as a front end, it greatly enhances the DSNP desirability as a simulation tool for education and research

  4. Creep-fatigue interaction at high temperature; Proceedings of the Symposium, 112th ASME Winter Annual Meeting, Atlanta, GA, Dec. 1-6, 1991

    Science.gov (United States)

    Haritos, George K.; Ochoa, O. O.

    Various papers on creep-fatigue interaction at high temperature are presented. Individual topics addressed include: analysis of elevated temperature fatigue crack growth mechanisms in Alloy 718, physically based microcrack propagation laws for creep-fatigue-environment interaction, in situ SEM observation of short fatigue crack growth in Waspaloy at 700 C under cyclic and dwell conditions, evolution of creep-fatigue life prediction models, TMF design considerations in turbine airfoils of advanced turbine engines. Also discussed are: high temperature fatigue life prediction computer code based on the total strain version of strainrange partitioning, atomic theory of thermodynamics of internal variables, geometrically nonlinear analysis of interlaminar stresses in unsymmetrically laminated plates subjected to uniform thermal loading, experimental investigation of creep crack tip deformation using moire interferometry. (For individual items see A93-31336 to A93-31344)

  5. Interactions between Glu-1 and Glu-3 loci and associations of selected molecular markers with quality traits in winter wheat (Triticum aestivum L.) DH lines.

    Science.gov (United States)

    Krystkowiak, Karolina; Langner, Monika; Adamski, Tadeusz; Salmanowicz, Bolesław P; Kaczmarek, Zygmunt; Krajewski, Paweł; Surma, Maria

    2017-02-01

    The quality of wheat depends on a large complex of genes and environmental factors. The objective of this study was to identify quantitative trait loci controlling technological quality traits and their stability across environments, and to assess the impact of interaction between alleles at loci Glu-1 and Glu-3 on grain quality. DH lines were evaluated in field experiments over a period of 4 years, and genotyped using simple sequence repeat markers. Lines were analysed for grain yield (GY), thousand grain weight (TGW), protein content (PC), starch content (SC), wet gluten content (WG), Zeleny sedimentation value (ZS), alveograph parameter W (APW), hectolitre weight (HW), and grain hardness (GH). A number of QTLs for these traits were identified in all chromosome groups. The Glu-D1 locus influenced TGW, PC, SC, WG, ZS, APW, GH, while locus Glu-B1 affected only PC, ZS, and WG. Most important marker-trait associations were found on chromosomes 1D and 5D. Significant effects of interaction between Glu-1 and Glu-3 loci on technological properties were recorded, and in all types of this interaction positive effects of Glu-D1 locus on grain quality were observed, whereas effects of Glu-B1 locus depended on alleles at Glu-3 loci. Effects of Glu-A3 and Glu-D3 loci per se were not significant, while their interaction with alleles present at other loci encoding HMW and LMW were important. These results indicate that selection of wheat genotypes with predicted good bread-making properties should be based on the allelic composition both in Glu-1 and Glu-3 loci, and confirm the predominant effect of Glu-D1d allele on technological properties of wheat grains.

  6. A Comparative Study of Simulated and Measured Gear-Flap Flow Interaction

    Science.gov (United States)

    Khorrami, Mehdi R.; Mineck, Raymond E.; Yao, Chungsheng; Jenkins, Luther N.; Fares, Ehab

    2015-01-01

    The ability of two CFD solvers to accurately characterize the transient, complex, interacting flowfield asso-ciated with a realistic gear-flap configuration is assessed via comparison of simulated flow with experimental measurements. The simulated results, obtained with NASA's FUN3D and Exa's PowerFLOW® for a high-fidelity, 18% scale semi-span model of a Gulfstream aircraft in landing configuration (39 deg flap deflection, main landing gear on and off) are compared to two-dimensional and stereo particle image velocimetry measurements taken within the gear-flap flow interaction region during wind tunnel tests of the model. As part of the bench-marking process, direct comparisons of the mean and fluctuating velocity fields are presented in the form of planar contour plots and extracted line profiles at measurement planes in various orientations stationed in the main gear wake. The measurement planes in the vicinity of the flap side edge and downstream of the flap trailing edge are used to highlight the effects of gear presence on tip vortex development and the ability of the computational tools to accurately capture such effects. The present study indicates that both computed datasets contain enough detail to construct a relatively accurate depiction of gear-flap flow interaction. Such a finding increases confidence in using the simulated volumetric flow solutions to examine the behavior of pertinent aer-odynamic mechanisms within the gear-flap interaction zone.

  7. Characterization of Hydrophobic Interactions of Polymers with Water and Phospholipid Membranes Using Molecular Dynamics Simulations

    Science.gov (United States)

    Drenscko, Mihaela

    Polymers and lipid membranes are both essential soft materials. The structure and hydrophobicity/hydrophilicity of polymers, as well as the solvent they are embedded in, ultimately determines their size and shape. Understating the variation of shape of the polymer as well as its interactions with model biological membranes can assist in understanding the biocompatibility of the polymer itself. Computer simulations, in particular molecular dynamics, can aid in characterization of the interaction of polymers with solvent, as well as polymers with model membranes. In this thesis, molecular dynamics serve to describe polymer interactions with a solvent (water) and with a lipid membrane. To begin with, we characterize the hydrophobic collapse of single polystyrene chains in water using molecular dynamics simulations. Specifically, we calculate the potential of mean force for the collapse of a single polystyrene chain in water using metadynamics, comparing the results between all atomistic with coarse-grained molecular simulation. We next explore the scaling behavior of the collapsed globular shape at the minimum energy configuration, characterized by the radius of gyration, as a function of chain length. The exponent is close to one third, consistent with that predicted for a polymer chain in bad solvent. We also explore the scaling behavior of the Solvent Accessible Surface Area (SASA) as a function of chain length, finding a similar exponent for both all-atomistic and coarse-grained simulations. Furthermore, calculation of the local water density as a function of chain length near the minimum energy configuration suggests that intermediate chain lengths are more likely to form dewetted states, as compared to shorter or longer chain lengths. Next, in order to investigate the molecular interactions between single hydrophobic polymer chains and lipids in biological membranes and at lipid membrane/solvent interface, we perform a series of molecular dynamics simulations of

  8. Employment and winter construction

    DEFF Research Database (Denmark)

    Hansen, Ernst Jan de Place; Larsen, Jacob Norvig

    2011-01-01

    Reduced seasonal building activity in the construction sector is often assumed to be related to hard winter conditions for building activities and poor working conditions for construction workers, resulting in higher costs and poor quality of building products, particularly in the northern hemisp...... of contracts for workers is more likely to explain differences in seasonal activity than climatic or technological factors....

  9. Titan's Emergence from Winter

    Science.gov (United States)

    Flasar, F. Michael; Achterberg, Richard; Jennings, Donald; Schinder, Paul

    2011-01-01

    We summarize the changes in Titans thermal structure derived from Cassini CIRS and radio-occultation data during the transition from winter to early spring. Titan's surface, and middle atmosphere show noticeable seasonal change, whereas that in most of the troposphere is mated. This can be understood in terms of the relatively small radiative relaxation time in the middle atmosphere and much larger time scale in the troposphere. The surface exhibits seasonal change because the heat capacity in an annual skin depth is much smaller than that in the lowest scale height of the troposphere. Surface temperatures rise 1 K at raid and high latitudes in the winter northern hemisphere and cool in the southern hemisphere. Changes in in the middle atmosphere are more complicated. Temperatures in the middle stratosphere (approximately 1 mbar) increase by a few kelvin at mid northern latitudes, but those at high latitudes first increase as that region moves out of winter shadow, and then decrease. This probably results from the combined effect of increased solar heating as the suit moves higher in the sky and the decreased adiabatic warming as the sinking motions associated with the cross-equatorial meridional cell weaken. Consistent with this interpretation, the warm temperatures observed higher up at the winter polar stratopause cool significantly.

  10. Remote Numerical Simulations of the Interaction of High Velocity Clouds with Random Magnetic Fields

    Science.gov (United States)

    Santillan, Alfredo; Hernandez--Cervantes, Liliana; Gonzalez--Ponce, Alejandro; Kim, Jongsoo

    The numerical simulations associated with the interaction of High Velocity Clouds (HVC) with the Magnetized Galactic Interstellar Medium (ISM) are a powerful tool to describe the evolution of the interaction of these objects in our Galaxy. In this work we present a new project referred to as Theoretical Virtual i Observatories. It is oriented toward to perform numerical simulations in real time through a Web page. This is a powerful astrophysical computational tool that consists of an intuitive graphical user interface (GUI) and a database produced by numerical calculations. In this Website the user can make use of the existing numerical simulations from the database or run a new simulation introducing initial conditions such as temperatures, densities, velocities, and magnetic field intensities for both the ISM and HVC. The prototype is programmed using Linux, Apache, MySQL, and PHP (LAMP), based on the open source philosophy. All simulations were performed with the MHD code ZEUS-3D, which solves the ideal MHD equations by finite differences on a fixed Eulerian mesh. Finally, we present typical results that can be obtained with this tool.

  11. Experimental simulation of lightning, interacting explosions and astrophysical jets with pulsed lasers

    International Nuclear Information System (INIS)

    Villagran-Muniz, M; Sobral, H; Navarro-Gonzalez, R; Velazquez, P F; Raga, A C

    2003-01-01

    Tabletop laboratory experiments have been used to simulate natural lightning, interacting explosions and astrophysical jets. When a high-energy laser pulse is focused in air, a laser-induced plasma (LIP) is produced, that generates a shock wave and an adiabatic expansion of the gas. In our work we have used LIPs in order to simulate lightning, for the study of chemical reactions relevant to atmospheric science. Several diagnostics have been applied to our LIPs, such as deflectometry, shadowgraphy and interferometry, which yield full spatial information of the process (electron density and temperature, the position of the shock wave fronts and the expansion of the hot gas), with a time resolution that ranges from nanoseconds to milliseconds. A new diagnostic alternative was implemented for shadowgraphy, which uses either continuous lasers or conventional light sources. The experimental results have been reproduced by hydrodynamic codes that we have developed. With astrophysical applications in mind, we have simulated and diagnosed the interaction of two explosions, with the aforementioned techniques. For this purpose, two LIPs are synchronized and diagnosed spatially and temporarily. Also, by producing the LIP in a glass sphere with a nozzle that ejects a shock wave and hot gas, we are able to simulate astrophysical jets. With such experiments, astrophysical models developed by us have been validated, showing excellent agreement between experiments and numerical simulations

  12. An iterative method for hydrodynamic interactions in Brownian dynamics simulations of polymer dynamics

    Science.gov (United States)

    Miao, Linling; Young, Charles D.; Sing, Charles E.

    2017-07-01

    Brownian Dynamics (BD) simulations are a standard tool for understanding the dynamics of polymers in and out of equilibrium. Quantitative comparison can be made to rheological measurements of dilute polymer solutions, as well as direct visual observations of fluorescently labeled DNA. The primary computational challenge with BD is the expensive calculation of hydrodynamic interactions (HI), which are necessary to capture physically realistic dynamics. The full HI calculation, performed via a Cholesky decomposition every time step, scales with the length of the polymer as O(N3). This limits the calculation to a few hundred simulated particles. A number of approximations in the literature can lower this scaling to O(N2 - N2.25), and explicit solvent methods scale as O(N); however both incur a significant constant per-time step computational cost. Despite this progress, there remains a need for new or alternative methods of calculating hydrodynamic interactions; large polymer chains or semidilute polymer solutions remain computationally expensive. In this paper, we introduce an alternative method for calculating approximate hydrodynamic interactions. Our method relies on an iterative scheme to establish self-consistency between a hydrodynamic matrix that is averaged over simulation and the hydrodynamic matrix used to run the simulation. Comparison to standard BD simulation and polymer theory results demonstrates that this method quantitatively captures both equilibrium and steady-state dynamics after only a few iterations. The use of an averaged hydrodynamic matrix allows the computationally expensive Brownian noise calculation to be performed infrequently, so that it is no longer the bottleneck of the simulation calculations. We also investigate limitations of this conformational averaging approach in ring polymers.

  13. Education and training of future nuclear engineers through the use of an interactive plant simulator

    International Nuclear Information System (INIS)

    Ahnert, C.; Cuervo, D.; Garcia-Herranz, N.; Aragones, J.M.; Cabellos, O.; Gallego, E.; Minguez, E.; Lorente, A.; Piedra, D.; Rebollo, L.; Blanco, J.

    2010-01-01

    The International Atomic Energy Agency (IAEA) sponsors the development of nuclear reactor simulators for education, or arranges the supply of such simulation programs. Aware of this, the Department of Nuclear Engineering of the Universidad Politecnica de Madrid was provided in 2008 with the Interactive Graphical Simulator of the Spanish nuclear power plant Jose Cabrera, whose operation ceased definitively in 2006. According with the IAEA-TECDOC- 1411, the simulator is a Graphical Simulator, used for training of main control room personnel, technical support engineers, and operations management. This paper presents all the work performed at the Department to turn the simulator into a teaching/learning tool, to be use in the nuclear engineering studies following guidance found in: Shtub, A. Parush, T.T. Hewett 'The use of simulation in learning and teaching' (Int. J. Eng. Educ., 25(2), 2009, pp. 206-208). The experience obtained so far with the use of the simulator has been very successful. The graduate students involved in the development of the projects, practices and documents related with the simulator show a great interest for the work that they are doing making that the laboratory where the simulator is installed to be busy place. Regarding the undergraduate students, the practices in the simulator encourage them to follow the Nuclear Energy studies in the Engineering Schools, what is very rewarding for the Department professors. The simulator has proved to be an optimal tool to transfer the knowledge of the physical phenomena that are involved in the nuclear power plants, from the nuclear reactor to the whole set of systems and equipments on a nuclear power plant. It is also a relevant tool for motivation of the students, and to complete the theoretical lessons. This use of the simulator in the learning-teaching process meats also the criteria recommended for the Bologna adapted studies, as it helps to increase the private hands-on work of the student, and

  14. Experimental validation of the fluid–structure interaction simulation of a bioprosthetic aortic heart valve

    International Nuclear Information System (INIS)

    Kemp, I.; Dellimore, K.; Rodriguez, R.; Scheffer, C.; Blaine, D.; Weich, H.; Doubell, A.

    2013-01-01

    Experiments performed on a 19 mm diameter bioprosthetic valve were used to successfully validate the fluid–structure interaction (FSI) simulation of an aortic valve at 72 bpm. The FSI simulation was initialized via a novel approach utilizing a Doppler sonogram of the experimentally tested valve. Using this approach very close quantitative agreement (≤12.5 %) between the numerical predictions and experimental values for several key valve performance parameters, including the peak systolic transvalvular pressure gradient, rapid valve opening time and rapid valve closing time, was obtained. The predicted valve leaflet kinematics during opening and closing were also in good agreement with the experimental measurements.

  15. Monitoring peptide-surface interaction by means of molecular dynamics simulation

    Energy Technology Data Exchange (ETDEWEB)

    Nonella, Marco, E-mail: mnonella@pci.uzh.ch [Physikalisch-Chemisches Institut, Universitaet Zuerich, Winterthurerstrasse 190, CH-8057 Zuerich (Switzerland); Seeger, Stefan, E-mail: sseeger@pci.uzh.ch [Physikalisch-Chemisches Institut, Universitaet Zuerich, Winterthurerstrasse 190, CH-8057 Zuerich (Switzerland)

    2010-12-09

    Graphical abstract: Protein-surface interactions play a crucial role in a wide field of research areas like biology, biotechnology, or pharmacology. Only recently, it has been shown that not only peptide adsorption represents an important process but also spreading and clustering of adsorbed proteins. By means of classical molecular dynamics, peptide adsorption as well as the dynamics of adsorbed peptides have been investigated in order to gain deeper insight into such processes. The picture shows a snapshot of an adsorbed peptide on a silica surface showing strong direct hydrogen bonding. Research highlights: {yields} Simulation of peptide surface interaction. {yields} Dynamics of hydrogen bond formation and destruction. {yields} Internal flexibility of adsorbed peptides. - Abstract: Protein adsorption and protein surface interactions have become an important research topic in recent years. Very recently, for example, it has been shown that protein clusters can undergo a surface-induced spreading after adsorption. Such phenomena emphasize the need of a more detailed insight into protein-silica interaction at an atomic level. Therefore, we have studied a model system consisting of a short peptide, a silica slab, and water molecules by means of classical molecular dynamics simulations. The study reveals that, besides of electrostatic interactions caused by the chosen charge distribution, the peptide interacts with the silica surface through formation of direct peptide-surface hydrogen bonds as well as indirect peptide-water-surface hydrogen bonds. The number of created hydrogen bonds varies considerably among the simulated structures. The strength of hydrogen bonding determines the mobility of the peptide on the surface and the internal flexibility of the adsorbed peptide.

  16. Interaction and dynamics of homologous pairing protein 2 (HOP2) and DNA studied by MD simulation

    Science.gov (United States)

    Moktan, Hem; Pezza, Roberto; Zhou, Donghua

    2015-03-01

    The homologous pairing protein 2 (Hop2) plays an important role in meiosis and DNA repair. Together with protein Mnd1, Hop2 enhances the strand invasion activity of recombinase Dmc1 by over 30 times, facilitating proper synapsis of homologous chromosomes. We recently determined the NMR structure of the N-terminal domain of Hop2 and proposed a model of Protein-DNA complex based on NMR chemical shift perturbations and mutagenesis studies (Moktan, J Biol Chem 2014 10.1074/jbc.M114.548180). However structure and dynamics of the complex have not been studied at the atomic level yet. Here, we used classical MD simulations to study the interactions between the N-terminal HOP2 and DNA. The simulated results indicate that helix3 (H3) interacts with DNA in major groove and wing1 (W1) interacts mostly in minor groove mainly via direct hydrogen bonds. Also it is found that binding leads to reduced fluctuations in both protein and DNA. Several water bridge interactions have been identified. The residue-wise contributions to the interaction energy were evaluated. Also the functional motion of the protein is analyzed using principal component analysis. The results confirmed the importance of H3 and W1 for the stability of the complex, which is consistent with our previous experimental studies.

  17. Fokker-Planck simulations of interactions of femtosecond laser pulses with dense plasmas

    International Nuclear Information System (INIS)

    Drska, L.; Limpouch, J.; Liska, R.

    1993-01-01

    The interaction of femtosecond laser pulses with fully ionized solid-state density plasmas in the regime of the normal skin effect was investigated by means of numerical simulation. For short wavelength lasers and 120 fs FWHM laser pulses the regime of normal skin effect is shown to hold for peak intensities up to 10 17 W/cm 2 . Basic characteristics of the interaction are revealed and certain departures of the electron distribution function, of the plasma dielectric constant and of laser absorption from simplistic models are pointed out. (author) 1 tab., 4 figs., 14 refs

  18. Multi-scale simulation of droplet-droplet interactions and coalescence

    CSIR Research Space (South Africa)

    Musehane, Ndivhuwo M

    2016-10-01

    Full Text Available Conference on Computational and Applied Mechanics Potchefstroom 3–5 October 2016 Multi-scale simulation of droplet-droplet interactions and coalescence 1,2Ndivhuwo M. Musehane?, 1Oliver F. Oxtoby and 2Daya B. Reddy 1. Aeronautic Systems, Council... topology changes that result when droplets interact. This work endeavours to eliminate the need to use empirical correlations based on phenomenological models by developing a multi-scale model that predicts the outcome of a collision between droplets from...

  19. Seasonal overturning circulation in the Red Sea: 2. Winter circulation

    KAUST Repository

    Yao, Fengchao; Hoteit, Ibrahim; Pratt, Lawrence J.; Bower, Amy S.; Kö hl, Armin; Gopalakrishnan, Ganesh; Rivas, David

    2014-01-01

    The shallow winter overturning circulation in the Red Sea is studied using a 50 year high-resolution MITgcm (MIT general circulation model) simulation with realistic atmospheric forcing. The overturning circulation for a typical year, represented

  20. Population reversal driven by unrestrained interactions in molecular dynamics simulations: A dialanine model

    Directory of Open Access Journals (Sweden)

    Filippo Pullara

    2015-10-01

    Full Text Available Standard Molecular Dynamics simulations (MD are usually performed under periodic boundary conditions using the well-established “Ewald summation”. This implies that the distance among each element in a given lattice cell and its corresponding element in another cell, as well as their relative orientations, are constant. Consequently, protein-protein interactions between proteins in different cells—important in many biological activities, such as protein cooperativity and physiological/pathological aggregation—are severely restricted, and features driven by protein-protein interactions are lost. The consequences of these restrictions, although conceptually understood and mentioned in the literature, have not been quantitatively studied before. The effect of protein-protein interactions on the free energy landscape of a model system, dialanine, is presented. This simple system features a free energy diagram with well-separated minima. It is found that, in the case of absence of peptide-peptide (p-p interactions, the ψ = 150° dihedral angle determines the most energetically favored conformation (global free-energy minimum. When strong p-p interactions are induced, the global minimum switches to the ψ = 0° conformation. This shows that the free-energy landscape of an individual molecule is dramatically affected by the presence of other freely interacting molecules of its same type. Results of the study suggest how taking into account p-p interactions in MD allows having a more realistic picture of system activity and functional conformations.

  1. An interactive simulation-based education system for BWR emergency, procedure guidelines

    Energy Technology Data Exchange (ETDEWEB)

    Tanikawa, Naoshi; Shida, Touichi [Hitachi Ltd (Japan). Hitachi Works; Ujita, Hiroshi; Yokota, Takeshi; Kato, Kanji [Hitachi Ltd, (Japan). Energy Research Lab.

    1994-12-31

    When applying EPGs (Emergency Procedure Guidelines), an operator decides the operational procedure by predicting the change of parameters from the plant status, because EPGs are described in a symptom style for emergency conditions. Technical knowledge of the plant behavior and its operation are necessary for operator to understand the EPGs. An interactive simulation-based education system, EPG-ICAI (Intelligent Computer Assisted Instruction), has been developed for BWR plant operators to acquire the knowledge of EPGs. EPG-ICAI is designed to realize an effective education by the step-by-step study by using an interactive real time simulator and an individual education by applying an intelligent tutoring function. (orig.) (2 refs., 7 figs., 1 tab.).

  2. Los Alamos Nuclear Plant Analyzer: an interactive power-plant simulation program

    International Nuclear Information System (INIS)

    Steinke, R.; Booker, C.; Giguere, P.; Liles, D.R.; Mahaffy, J.H.; Turner, M.R.

    1984-01-01

    The Nuclear Plant Analyzer (NPA) is a computer-software interface for executing the TRAC or RELAP5 power-plant systems codes. The NPA is designed to use advanced supercomputers, long-distance data communications, and a remote workstation terminal with interactive computer graphics to analyze power-plant thermal-hydraulic behavior. The NPA interface simplifies the running of these codes through automated procedures and dialog interaction. User understanding of simulated-plant behavior is enhanced through graphics displays of calculational results. These results are displayed concurrently with the calculation. The user has the capability to override the plant's modeled control system with hardware-adjustment commands. This gives the NPA the utility of a simulator, and at the same time, the accuracy of an advanced, best-estimate, power-plant systems code for plant operation and safety analysis

  3. An improved simulation routine for modelling coherent high-energy proton interactions with bent crystals

    CERN Document Server

    AUTHOR|(CDS)2210072; Mirarchi, Daniele; Redaelli, Stefano

    The planes in crystalline solids can constrain the directions that charged particles take as they pass through. Physicists can use this "channelling" property of crystals to steer particle beams. In a bent crystal, for example, channelled particles follow the bend and can change their direction. Experiments are being carried out to study in detail this phenomenon. The UA9 collaboration is using high energy protons and heavy ions beams from the SPS accelerator at CERN to verify the possibility of using bent crystals as primary collimators in high energy hadron colliders like the LHC. Simulations have been developed to model the coherent interaction with crystal planes. The goal of the thesis is indeed to analyze the data and develop an improved simulation routine to better describe the data’s subtleties, in particular the transition between the volume reflection and amorphous modes of beam interaction with the crystal.

  4. Prediction of drug-packaging interactions via molecular dynamics (MD) simulations.

    Science.gov (United States)

    Feenstra, Peter; Brunsteiner, Michael; Khinast, Johannes

    2012-07-15

    The interaction between packaging materials and drug products is an important issue for the pharmaceutical industry, since during manufacturing, processing and storage a drug product is continuously exposed to various packaging materials. The experimental investigation of a great variety of different packaging material-drug product combinations in terms of efficacy and safety can be a costly and time-consuming task. In our work we used molecular dynamics (MD) simulations in order to evaluate the applicability of such methods to pre-screening of the packaging material-solute compatibility. The solvation free energy and the free energy of adsorption of diverse solute/solvent/solid systems were estimated. The results of our simulations agree with experimental values previously published in the literature, which indicates that the methods in question can be used to semi-quantitatively reproduce the solid-liquid interactions of the investigated systems. Copyright © 2012 Elsevier B.V. All rights reserved.

  5. An interactive simulation-based education system for BWR emergency, procedure guidelines

    International Nuclear Information System (INIS)

    Tanikawa, Naoshi; Shida, Touichi; Ujita, Hiroshi; Yokota, Takeshi; Kato, Kanji

    1994-01-01

    When applying EPGs (Emergency Procedure Guidelines), an operator decides the operational procedure by predicting the change of parameters from the plant status, because EPGs are described in a symptom style for emergency conditions. Technical knowledge of the plant behavior and its operation are necessary for operator to understand the EPGs. An interactive simulation-based education system, EPG-ICAI (Intelligent Computer Assisted Instruction), has been developed for BWR plant operators to acquire the knowledge of EPGs. EPG-ICAI is designed to realize an effective education by the step-by-step study by using an interactive real time simulator and an individual education by applying an intelligent tutoring function. (orig.) (2 refs., 7 figs., 1 tab.)

  6. An improved simulation routine for modelling coherent high-energy proton interactions with bent crystals

    CERN Document Server

    Forcher, Francesco; Redaelli, Stefano; Zanetti, Marco; CERN. Geneva. ATS Department

    2018-01-01

    The planes in crystalline solids can constrain the directions that charged particles take as they pass through. Physicists can use this "channelling" property of crystals to steer particle beams. In a bent crystal, for example, channelled particles follow the bend and can change their direction. Several studies are on-going at CERN to verify the possibility of using bent crystals as primary collimators in high energy hadron colliders like the LHC. Simulations have been developed to model the coherent interaction with crystalline planes. The goal of this note is to analyze the data collected on extracted beam from the SPS and develop an improved model to simulate the data’s subtleties, in particular the transition between the volume reflection and amorphous interactions of the beam with crystals.

  7. Final Report. Coupled simulations of Antarctic Ice-sheet/ocean interactions using POP and CISM

    Energy Technology Data Exchange (ETDEWEB)

    Asay-Davis, Xylar Storm [Potsdam Institute for Climate Impact Research, Potdam (Germany)

    2015-12-30

    The project performed under this award, referred to from here on as CLARION (CoupLed simulations of Antarctic Ice-sheet/Ocean iNteractions), included important advances in two models of ice sheet and ocean interactions. Despite its short duration (one year), the project made significant progress on its three major foci. First, together with collaborator Daniel Martin at Lawrence Berkeley National Laboratory (LBNL), I developed the POPSICLES coupled ice sheet-ocean model to the point where it could perform a number of pan-Antarctic simulations under various forcing conditions. The results were presented at a number of major conferences and workshops worldwide, and are currently being incorporated into two manuscripts in preparation.

  8. Nuclear Plant Analyzer: an interactive TRAC/RELAP Power-Plant Simulation Program

    International Nuclear Information System (INIS)

    Steinke, R.; Booker, C.; Giguere, P.; Liles, D.; Mahaffy, J.; Turner, M.; Wiley, R.

    1984-01-01

    The Nuclear Plant Analyzer (NPA) is a computer-software interface for executing the TRAC or RELAP5 power-plant systems codes. The NPA is designed to use advanced supercomputers, long-distance data communications, and a remote workstation terminal with interactive computer graphics to analyze power-plant thermal-hydraulic behavior. The NPA interface simplifies the running of these codes through automated procedures and dialog interaction. User understanding of simulated-plant behavior is enhanced through graphics displays of calculational results. These results are displayed concurrently with the calculation. The user has the capability to override the plant's modeled control system with hardware adjustment commands. This gives the NPA the utility of a simulator, and at the same time, the accuracy of an advanced, best-estimate, power-plant systems code for plant operation and safety analysis

  9. Advances in Computational Fluid-Structure Interaction and Flow Simulation Conference

    CERN Document Server

    Takizawa, Kenji

    2016-01-01

    This contributed volume celebrates the work of Tayfun E. Tezduyar on the occasion of his 60th birthday. The articles it contains were born out of the Advances in Computational Fluid-Structure Interaction and Flow Simulation (AFSI 2014) conference, also dedicated to Prof. Tezduyar and held at Waseda University in Tokyo, Japan on March 19-21, 2014. The contributing authors represent a group of international experts in the field who discuss recent trends and new directions in computational fluid dynamics (CFD) and fluid-structure interaction (FSI). Organized into seven distinct parts arranged by thematic topics, the papers included cover basic methods and applications of CFD, flows with moving boundaries and interfaces, phase-field modeling, computer science and high-performance computing (HPC) aspects of flow simulation, mathematical methods, biomedical applications, and FSI. Researchers, practitioners, and advanced graduate students working on CFD, FSI, and related topics will find this collection to be a defi...

  10. Interactions between Nanoparticles and Polymer Brushes: Molecular Dynamics Simulations and Self-consistent Field Theory Calculations

    Science.gov (United States)

    Cheng, Shengfeng; Wen, Chengyuan; Egorov, Sergei

    2015-03-01

    Molecular dynamics simulations and self-consistent field theory calculations are employed to study the interactions between a nanoparticle and a polymer brush at various densities of chains grafted to a plane. Simulations with both implicit and explicit solvent are performed. In either case the nanoparticle is loaded to the brush at a constant velocity. Then a series of simulations are performed to compute the force exerted on the nanoparticle that is fixed at various distances from the grafting plane. The potential of mean force is calculated and compared to the prediction based on a self-consistent field theory. Our simulations show that the explicit solvent leads to effects that are not captured in simulations with implicit solvent, indicating the importance of including explicit solvent in molecular simulations of such systems. Our results also demonstrate an interesting correlation between the force on the nanoparticle and the density profile of the brush. We gratefully acknowledge the support of NVIDIA Corporation with the donation of the Tesla K40 GPU used for this research.

  11. Ensemble of European regional climate simulations for the winter of 2013 and 2014 from HadAM3P-RM3P

    Science.gov (United States)

    Schaller, Nathalie; Sparrow, Sarah N.; Massey, Neil R.; Bowery, Andy; Miller, Jonathan; Wilson, Simon; Wallom, David C. H.; Otto, Friederike E. L.

    2018-04-01

    Large data sets used to study the impact of anthropogenic climate change on the 2013/14 floods in the UK are provided. The data consist of perturbed initial conditions simulations using the Weather@Home regional climate modelling framework. Two different base conditions, Actual, including atmospheric conditions (anthropogenic greenhouse gases and human induced aerosols) as at present and Natural, with these forcings all removed are available. The data set is made up of 13 different ensembles (2 actual and 11 natural) with each having more than 7500 members. The data is available as NetCDF V3 files representing monthly data within the period of interest (1st Dec 2013 to 15th February 2014) for both a specified European region at a 50 km horizontal resolution and globally at N96 resolution. The data is stored within the UK Natural and Environmental Research Council Centre for Environmental Data Analysis repository.

  12. Local Interaction Simulation Approach for Fault Detection in Medical Ultrasonic Transducers

    Directory of Open Access Journals (Sweden)

    Z. Hashemiyan

    2015-01-01

    Full Text Available A new approach is proposed for modelling medical ultrasonic transducers operating in air. The method is based on finite elements and the local interaction simulation approach. The latter leads to significant reductions of computational costs. Transmission and reception properties of the transducer are analysed using in-air reverberation patterns. The proposed approach can help to provide earlier detection of transducer faults and their identification, reducing the risk of misdiagnosis due to poor image quality.

  13. Fluid-structure interaction modeling of wind turbines: simulating the full machine

    Science.gov (United States)

    Hsu, Ming-Chen; Bazilevs, Yuri

    2012-12-01

    In this paper we present our aerodynamics and fluid-structure interaction (FSI) computational techniques that enable dynamic, fully coupled, 3D FSI simulation of wind turbines at full scale, and in the presence of the nacelle and tower (i.e., simulation of the "full machine"). For the interaction of wind and flexible blades we employ a nonmatching interface discretization approach, where the aerodynamics is computed using a low-order finite-element-based ALE-VMS technique, while the rotor blades are modeled as thin composite shells discretized using NURBS-based isogeometric analysis (IGA). We find that coupling FEM and IGA in this manner gives a good combination of efficiency, accuracy, and flexibility of the computational procedures for wind turbine FSI. The interaction between the rotor and tower is handled using a non-overlapping sliding-interface approach, where both moving- and stationary-domain formulations of aerodynamics are employed. At the fluid-structure and sliding interfaces, the kinematic and traction continuity is enforced weakly, which is a key ingredient of the proposed numerical methodology. We present several simulations of a three-blade 5~MW wind turbine, with and without the tower. We find that, in the case of no tower, the presence of the sliding interface has no effect on the prediction of aerodynamic loads on the rotor. From this we conclude that weak enforcement of the kinematics gives just as accurate results as the strong enforcement, and thus enables the simulation of rotor-tower interaction (as well as other applications involving mechanical components in relative motion). We also find that the blade passing the tower produces a 10-12 % drop (per blade) in the aerodynamic torque. We feel this finding may be important when it comes to the fatigue-life analysis and prediction for wind turbine blades.

  14. Simulation of Past Life: Controlling Agent Behaviors from the Interactions between Ethnic Groups

    OpenAIRE

    Lim , Chen-Kim; Cani , Marie-Paule; Galvane , Quentin; Pettré , Julien; Abdullah Zawawi , Talib

    2013-01-01

    International audience; Many efforts have been carried out in preserving the history and culture of Penang and also other regions of Malaysia since George Town was elected as a UNESCO living heritage city. This paper presents a method to simulate life in a local trading port in the 1800s, where various populations with very different social rules interacted with each other. These populations included Indian coolies, Malay vendors, British colonists and Chinese traders. The challenge is to mod...

  15. Two Methods For Simulating the Strong-Strong Beam-Beam Interaction in Hadron Colliders

    International Nuclear Information System (INIS)

    Warnock, Robert L.

    2002-01-01

    We present and compare the method of weighted macro particle tracking and the Perron-Frobenius operator technique for simulating the time evolution of two beams coupled via the collective beam-beam interaction in 2-D and 4-D (transverse) phase space. The coherent dipole modes, with and without lattice nonlinearities and external excitation, are studied by means of the Vlasov-Poisson system

  16. Design and simulation of a sub-terahertz folded-waveguide extended interaction oscillator

    Science.gov (United States)

    Liu, Wenxin; Zhang, Zhaochuan; Zhao, Chao; Guo, Xin; Liao, Suying

    2017-06-01

    In this paper, an interesting type of a two-section folded wave-guide (TSFW) slow wave structure (SWS) for the development of sub-Terahertz (sub-THz) extended interaction oscillator (EIO) is proposed. In this sub-THz device, the prebunching electron beam is produced by the TSFW SWS, which results in the enhancement of the output power. To verify this concept, the TSFW for sub-THz EIO is developed, which includes the design, simulation, and some fabrications. A small size of electron optics system (EOS), the TSFW SWS for beam-wave interactions, and the output structure are studied with simulations. Through the codes Egun and Superfish, the EOS is designed and optimized. With a help of CST studio and 3D particle-in-cell (PIC) simulation CHIPIC, the characteristics of beam-wave interaction generated by the TSFW are studied. The results of PIC simulation show that the output power is remarkably enhanced by a factor of 3, which exceeds 200 W at the frequency of 108 GHz. Based on the optimum parameters, the TSFW is manufactured with a high speed numerical mill, and the test transmission characteristic |S21| is 13 dB. At last, the output structure with a pill-box window is optimized, fabricated, integrated, and tested, and the result shows that the voltage standing-wave ratio of the window is about 2.2 at an operating frequency of 108 GHz. This design and simulation can provide an effective method to develop high power THz sources.

  17. Teaching Experience: How to Make and Use PowerPoint-Based Interactive Simulations for Undergraduate IR Teaching

    Science.gov (United States)

    Meibauer, Gustav; Aagaard Nøhr, Andreas

    2018-01-01

    This article is about designing and implementing PowerPoint-based interactive simulations for use in International Relations (IR) introductory undergraduate classes based on core pedagogical literature, models of human skill acquisition, and previous research on simulations in IR teaching. We argue that simulations can be usefully employed at the…

  18. Simulation of mode converted ion Bernstein wave - beam deuteron interactions on TFTR

    Science.gov (United States)

    Herrmann, Mark; Fisch, Nathaniel

    1998-11-01

    Experiments on TFTR have documented strong interactions between mode converted ion Bernstein waves (MCIBW) and beam deuterons(D. S. Darrow et al.), Nucl. Fusion 36, 509 (1996).^,(N. J. Fisch et al.), IAEA, Vol. 1, p. 271 (1996). This is of particular interest in the study of α channelling, since the most promising scenarios(M. C. Herrmann and N. J. Fisch, Phys. Rev. Lett. 79), 1495 (1997). rely on a suitable combination of MCIBW and Alfvén eigenmodes to achieve the cooling of the α particles. Collisional effects, realistic wave fields, and a detailed model of the wave-particle interaction have been added to the Monte Carlo simulations which are used to simulate α channelling in order to model TFTR experiments(M. C. Herrmann, Ph.D. thesis, Princeton University, 1998.). The results are found to be in qualitative agreement with the data. In addition, the simulation is used, in conjunction with the data, to demonstrate the existence of the k_\\|-flip of the MCIBW, and to infer a diffusion coefficient for the beam deuterons interacting with the wave. This diffusion coefficient significantly exceeds what would be expected on the basis of quasilinear theory with the fields specified by 1 D ray tracing of the MCIBW.

  19. Molecular Dynamics Simulation of Barnase: Contribution of Noncovalent Intramolecular Interaction to Thermostability

    Directory of Open Access Journals (Sweden)

    Zhiguo Chen

    2013-01-01

    Full Text Available Bacillus amyloliquefaciens ribonuclease Barnase (RNase Ba is a 12 kD (kilodalton small extracellular ribonuclease. It has broad application prospects in agriculture, clinical medicine, pharmaceutical, and so forth. In this work, the thermal stability of Barnase has been studied using molecular dynamics simulation at different temperatures. The present study focuses on the contribution of noncovalent intramolecular interaction to protein stability and how they affect the thermal stability of the enzyme. Profiles of root mean square deviation and root mean square fluctuation identify thermostable and thermosensitive regions of Barnase. Analyses of trajectories in terms of secondary structure content, intramolecular hydrogen bonds and salt bridge interactions indicate distinct differences in different temperature simulations. In the simulations, Four three-member salt bridge networks (Asp8-Arg110-Asp12, Arg83-Asp75-Arg87, Lys66-Asp93-Arg69, and Asp54-Lys27-Glu73 have been identified as critical salt bridges for thermostability which are maintained stably at higher temperature enhancing stability of three hydrophobic cores. The study may help enlighten our knowledge of protein structural properties, noncovalent interactions which can stabilize secondary peptide structures or promote folding, and also help understand their actions better. Such an understanding is required for designing efficient enzymes with characteristics for particular applications at desired working temperatures.

  20. Characterization of the Interaction between Gallic Acid and Lysozyme by Molecular Dynamics Simulation and Optical Spectroscopy

    Directory of Open Access Journals (Sweden)

    Minzhong Zhan

    2015-07-01

    Full Text Available The binding interaction between gallic acid (GA and lysozyme (LYS was investigated and compared by molecular dynamics (MD simulation and spectral techniques. The results from spectroscopy indicate that GA binds to LYS to generate a static complex. The binding constants and thermodynamic parameters were calculated. MD simulation revealed that the main driving forces for GA binding to LYS are hydrogen bonding and hydrophobic interactions. The root-mean-square deviation verified that GA and LYS bind to form a stable complex, while the root-mean-square fluctuation results showed that the stability of the GA-LYS complex at 298 K was higher than that at 310 K. The calculated free binding energies from the molecular mechanics/Poisson-Boltzmann surface area method showed that van der Waals forces and electrostatic interactions are the predominant intermolecular forces. The MD simulation was consistent with the spectral experiments. This study provides a reference for future study of the pharmacological mechanism of GA.

  1. Hydroacoustic simulation of rotor-stator interaction in resonance conditions in Francis pump-turbine

    International Nuclear Information System (INIS)

    Nicolet, C; Ruchonnet, N; Alligne, S; Avellan, F; Koutnik, J

    2010-01-01

    Combined effect of rotating pressure field related to runner blade and wakes of wicket gates leads to rotor stator interactions, RSI, in Francis pump-turbines. These interactions induce pressures waves propagating in the entire hydraulic machine. Superposition of those pressure waves may result in standing wave in the spiral casing and rotating diametrical mode in the guide vanes and can cause strong pressure fluctuations and vibrations. This paper presents the modeling, simulation and analysis of Rotor-Stator Interaction of a scale model of a Francis pump-turbine and related test rig using a one-dimensional approach. The hydroacoustic modeling of the Francis pump-turbine takes into account the spiral casing, the 20 guide vanes, the 9 rotating runner vanes. The connection between stationary and rotating parts is ensured by a valve network driven according to the unsteady flow distribution between guide vanes and runner vanes. Time domain simulations are performed for 2 different runner rotational speeds in turbine mode. The simulation results are analyzed in frequency domain and highlights hydroacoustic resonance between RSI excitations and the spiral case. Rotating diametrical mode in the vaneless gap and standing wave in the spiral case are identified. The influence of the resonance on phase and amplitude of pressure fluctuations obtained for both the spiral case and the vaneless gap is analyzed. The mode shape and frequencies are confirmed using eigenvalues analysis.

  2. Advanced computational simulations of water waves interacting with wave energy converters

    Science.gov (United States)

    Pathak, Ashish; Freniere, Cole; Raessi, Mehdi

    2017-03-01

    Wave energy converter (WEC) devices harness the renewable ocean wave energy and convert it into useful forms of energy, e.g. mechanical or electrical. This paper presents an advanced 3D computational framework to study the interaction between water waves and WEC devices. The computational tool solves the full Navier-Stokes equations and considers all important effects impacting the device performance. To enable large-scale simulations in fast turnaround times, the computational solver was developed in an MPI parallel framework. A fast multigrid preconditioned solver is introduced to solve the computationally expensive pressure Poisson equation. The computational solver was applied to two surface-piercing WEC geometries: bottom-hinged cylinder and flap. Their numerically simulated response was validated against experimental data. Additional simulations were conducted to investigate the applicability of Froude scaling in predicting full-scale WEC response from the model experiments.

  3. Polyphilic Interactions as Structural Driving Force Investigated by Molecular Dynamics Simulation (Project 7

    Directory of Open Access Journals (Sweden)

    Christopher Peschel

    2017-09-01

    Full Text Available We investigated the effect of fluorinated molecules on dipalmitoylphosphatidylcholine (DPPC bilayers by force-field molecular dynamics simulations. In the first step, we developed all-atom force-field parameters for additive molecules in membranes to enable an accurate description of those systems. On the basis of this force field, we performed extensive simulations of various bilayer systems containing different additives. The additive molecules were chosen to be of different size and shape, and they included small molecules such as perfluorinated alcohols, but also more complex molecules. From these simulations, we investigated the structural and dynamic effects of the additives on the membrane properties, as well as the behavior of the additive molecules themselves. Our results are in good agreement with other theoretical and experimental studies, and they contribute to a microscopic understanding of interactions, which might be used to specifically tune membrane properties by additives in the future.

  4. Simulation of the beam halo from the beam-beam interaction in LEP

    International Nuclear Information System (INIS)

    Chen, T.; Irwin, J.; Siemann, R.

    1994-02-01

    The luminosity lifetimes of e + e - colliders are often dominated by the halo produced by the beam-beam interaction. They have developed a simulation technique to model this halo using the flux across boundaries in amplitude space to decrease the CPU time by a factor of one-hundred or more over 'brute force' tracking. It allows simulation of density distributions and halos corresponding to realistic lifetimes. Reference 1 shows the agreement with brute force tracking in a number of cases and the importance of beam-beam resonances in determining the density distribution of large amplitudes. this research is now directed towards comparisons with operating colliders and studies of the combined effects of lattice and beam-beam nonlinearities. LEP offers an ideal opportunity for both, and in this paper they are presenting the first results of LEP simulations

  5. Modelling phosphorus (P), sulphur (S) and iron (Fe) interactions during the simulation of anaerobic digestion processes

    DEFF Research Database (Denmark)

    Flores-Alsina, Xavier; Solon, Kimberly; Kazadi-Mbamba, Christian

    2015-01-01

    This paper examines the effects of different model formulations when describing sludge stabilization processes in wastewater treatment plants by the Anaerobic Digestion Model No. 1 (ADM1). The proposed model extensions describe the interactions amongst phosphorus (P), sulfur (S), iron (Fe......) and their potential effect on total biogas production (CO2, CH4, H2 and H2S). The ADM1 version, implemented in the plant-wide context provided by the Benchmark Simulation Model No. 2 (BSM2), is used as the basic platform (A0). Four (A1 – A4) different model extensions are implemented, simulated and evaluated......2) as the electron donor. Finally, the last evaluated approach (A4) is based on accounting for Multiple Mineral Precipitation. The ADM1 thereby switches from a 2-phase (aqueous-gas) to a 3-phase (aqueous-gas-solid) system. Simulation results show that the implementations of A1 and A2 lead...

  6. Modeling and Simulation of the Longitudinal Beam Dynamics - RF Station Interaction in the LHC Rings

    International Nuclear Information System (INIS)

    Mastorides, T

    2008-01-01

    A non-linear time-domain simulation has been developed to study the interaction between longitudinal beam dynamics and RF stations in the LHC rings. The motivation for this tool is to determine optimal LLRF configurations, to study system sensitivity on various parameters, and to define the operational and technology limits. It will be also used to study the effect of RF station noise, impedance, and perturbations on the beam life time and longitudinal emittance. It allows the study of alternative LLRF implementations and control algorithms. The insight and experience gained from our PEP-II simulation is important for this work. In this paper we discuss properties of the simulation tool that will be helpful in analyzing the LHC RF system and its initial results. Partial verification of the model with data taken during the LHC RF station commissioning is presented

  7. Simulation of Guided Wave Interaction with In-Plane Fiber Waviness

    Science.gov (United States)

    Leckey, Cara A. C.; Juarez, Peter D.

    2016-01-01

    Reducing the timeline for certification of composite materials and enabling the expanded use of advanced composite materials for aerospace applications are two primary goals of NASA's Advanced Composites Project (ACP). A key a technical challenge area for accomplishing these goals is the development of rapid composite inspection methods with improved defect characterization capabilities. Ongoing work at NASA Langley is focused on expanding ultrasonic simulation capabilities for composite materials. Simulation tools can be used to guide the development of optimal inspection methods. Custom code based on elastodynamic finite integration technique is currently being developed and implemented to study ultrasonic wave interaction with manufacturing defects, such as in-plane fiber waviness (marcelling). This paper describes details of validation comparisons performed to enable simulation of guided wave propagation in composites containing fiber waviness. Simulation results for guided wave interaction with in-plane fiber waviness are also discussed. The results show that the wavefield is affected by the presence of waviness on both the surface containing fiber waviness, as well as the opposite surface to the location of waviness.

  8. Dynamical simulations of the interacting galaxies in the NGC 520/UGC 957 system

    Science.gov (United States)

    Stanford, S. A.; Balcells, Marc

    1991-01-01

    Numerical simulations of the interacting galaxies in the NGC 520/UGC 957 system are presented. Two sets of models were produced to investigate the postulated three-galaxy system of two colliding disk galaxies within NGC 520 and the dwarf galaxy UGC 957. The first set of models simulated a dwarf perturbing one-disk galaxy, which tested the possibility that NGC 520 contains only one galaxy disturbed by the passage of UGC 957. The resulting morphology of the perturbed single disk in the simulation fails to reproduce the observed tidal tails and northwest mass condensation of NGC 520. A second set of models simulated two colliding disks, which tested the hypothesis that NGC 520 itself contains two galaxies in a strong collision and UGC 957 is unimportant to the interaction. These disk-disk models produced a good match to the morphology of the present NGC 520. It is concluded that (1) NGC 520 contains two colliding disk galaxies which have produced the brighter southern half of the long tidal tail and (2) UGC 957, which may originally have been a satellite of one of the disk galaxies, formed the diffuse northern tail as it orbited NGC 520.

  9. Design, development, and evaluation of an interactive simulator for engineering ethics education (SEEE).

    Science.gov (United States)

    Chung, Christopher A; Alfred, Michael

    2009-06-01

    Societal pressures, accreditation organizations, and licensing agencies are emphasizing the importance of ethics in the engineering curriculum. Traditionally, this subject has been taught using dogma, heuristics, and case study approaches. Most recently a number of organizations have sought to increase the utility of these approaches by utilizing the Internet. Resources from these organizations include on-line courses and tests, videos, and DVDs. While these individual approaches provide a foundation on which to base engineering ethics, they may be limited in developing a student's ability to identify, analyze, and respond to engineering ethics situations outside of the classroom environment. More effective approaches utilize a combination of these types of approaches. This paper describes the design and development of an internet based interactive Simulator for Engineering Ethics Education. The simulator places students in first person perspective scenarios involving different types of ethical situations. Students must gather data, assess the situation, and make decisions. This requires students to develop their own ability to identify and respond to ethical engineering situations. A limited comparison between the internet based interactive simulator and conventional internet web based instruction indicates a statistically significant improvement of 32% in instructional effectiveness. The simulator is currently being used at the University of Houston to help fulfill ABET requirements.

  10. Towards Online Visualization and Interactive Monitoring of Real-Time CFD Simulations on Commodity Hardware

    Directory of Open Access Journals (Sweden)

    Nils Koliha

    2015-09-01

    Full Text Available Real-time rendering in the realm of computational fluid dynamics (CFD in particular and scientific high performance computing (HPC in general is a comparably young field of research, as the complexity of most problems with practical relevance is too high for a real-time numerical simulation. However, recent advances in HPC and the development of very efficient numerical techniques allow running first optimized numerical simulations in or near real-time, which in return requires integrated and optimized visualization techniques that do not affect performance. In this contribution, we present concepts, implementation details and several application examples of a minimally-invasive, efficient visualization tool for the interactive monitoring of 2D and 3D turbulent flow simulations on commodity hardware. The numerical simulations are conducted with ELBE, an efficient lattice Boltzmann environment based on NVIDIA CUDA (Compute Unified Device Architecture, which provides optimized numerical kernels for 2D and 3D computational fluid dynamics with fluid-structure interactions and turbulence.

  11. Large-eddy simulation of wind turbine wake interactions on locally refined Cartesian grids

    Science.gov (United States)

    Angelidis, Dionysios; Sotiropoulos, Fotis

    2014-11-01

    Performing high-fidelity numerical simulations of turbulent flow in wind farms remains a challenging issue mainly because of the large computational resources required to accurately simulate the turbine wakes and turbine/turbine interactions. The discretization of the governing equations on structured grids for mesoscale calculations may not be the most efficient approach for resolving the large disparity of spatial scales. A 3D Cartesian grid refinement method enabling the efficient coupling of the Actuator Line Model (ALM) with locally refined unstructured Cartesian grids adapted to accurately resolve tip vortices and multi-turbine interactions, is presented. Second order schemes are employed for the discretization of the incompressible Navier-Stokes equations in a hybrid staggered/non-staggered formulation coupled with a fractional step method that ensures the satisfaction of local mass conservation to machine zero. The current approach enables multi-resolution LES of turbulent flow in multi-turbine wind farms. The numerical simulations are in good agreement with experimental measurements and are able to resolve the rich dynamics of turbine wakes on grids containing only a small fraction of the grid nodes that would be required in simulations without local mesh refinement. This material is based upon work supported by the Department of Energy under Award Number DE-EE0005482 and the National Science Foundation under Award number NSF PFI:BIC 1318201.

  12. [The interactive neuroanatomical simulation and practical application of frontotemporal transsylvian exposure in neurosurgery].

    Science.gov (United States)

    Balogh, Attila; Czigléczki, Gábor; Papal, Zsolt; Preul, Mark C; Banczerowski, Péter

    2014-11-30

    There is an increased need for new digital education tools in neurosurgical training. Illustrated textbooks offer anatomic and technical reference but do not substitute hands-on experience provided by surgery or cadaver dissection. Due to limited availability of cadaver dissections the need for development of simulation tools has been augmented. We explored simulation technology for producing virtual reality-like reconstructions of simulated surgical approaches on cadaver. Practical application of the simulation tool has been presented through frontotemporal transsylvian exposure. The dissections were performed on two cadaveric heads. Arteries and veins were prepared and injected with colorful silicon rubber. The heads were rigidly fixed in Mayfield headholder. A robotic microscope with two digital cameras in inverted cone method of image acquisition was used to capture images around a pivot point in several phases of dissections. Multilayered, high-resolution images have been built into interactive 4D environment by custom developed software. We have developed the simulation module of the frontotemporal transsylvian approach. The virtual specimens can be rotated or tilted to any selected angles and examined from different surgical perspectives at any stage of dissections. Important surgical issues such as appropriate head positioning or surgical maneuvers to expose deep situated neuroanatomic structures can be simulated and studied by using the module. The simulation module of the frontotemporal transsylvian exposure helps to examine effect of head positioning on the visibility of deep situated neuroanatomic structures and study surgical maneuvers required to achieve optimal exposure of deep situated anatomic structures. The simulation program is a powerful tool to study issues of preoperative planning and well suited for neurosurgical training.

  13. Editorial - The winter Atomiades

    CERN Multimedia

    Staff Association

    2011-01-01

    As we wrote in our previous editorial, the Staff Association gives direct support to sports events, such as the Atomiades, a section of the Association of Sports Communities of European Research Institutes, which brings together sportsmen and women from 38 European research centres in 13 countries (Austria, Belgium, Czech Republic, United Kingdom, Finland, France, Germany, Hungary, Italy, Luxemburg, the Netherlands, Russia, and Switzerland). The summer Atomiades take place between the months of June and September every three years. Thirteen such events have taken place since 1973, the last one in June 2009 in Berlin. As far as the winter Atomiades are concerned, also organized every three years, and alternating with the summer Atomiades, there have been eleven since 1981, the last one at the end of January this year in neighbouring France. The following article tells the wonderful adventure of the CERN staff who took part in this event. A positive outcome for CERN skiers at the winter Atomiades The 11t...

  14. Numerical simulation of the interaction of elements of active protection with metal barriers

    Science.gov (United States)

    Radchenko, P. A.; Batuev, S. P.; Radchenko, A. V.

    2017-10-01

    The present paper is aimed at working out the algorithm of multi-contact interaction of solid bodies; it studies the influence of the shape of projectile (damage agent) on its penetration capability. Steel projectiles of different shape have been considered as damage agents: sphere, regular tetrahedron, cube, cylinder and plate. The weight of projectiles has been kept the same. Antitank grenade has been used as a target. The study has been conducted by means of numerical simulation using finite element analysis. The simulation is three-dimensional. Behavior of materials has been described by elasto-plastic model taking into consideration the fracture and fragmentation of interacting bodies. The speed of interaction has been considered within the range of 800 to 2000 m/s. Research results demonstrated significant influence of the projectile shape on its penetration capability. Projectile in the shape of elongated cylinder has shown better penetration capability. Considering the weight of damage agents (except for sphere and plate) their maximum penetration capability has been reached at the speed of 1400 m/s. Increase of the speed of interaction has been followed by intensive fracture of damage agents and their penetration capability thus has worsened.

  15. Parallel Beam-Beam Simulation Incorporating Multiple Bunches and Multiple Interaction Regions

    CERN Document Server

    Jones, F W; Pieloni, T

    2007-01-01

    The simulation code COMBI has been developed to enable the study of coherent beam-beam effects in the full collision scenario of the LHC, with multiple bunches interacting at multiple crossing points over many turns. The program structure and input are conceived in a general way which allows arbitrary numbers and placements of bunches and interaction points (IP's), together with procedural options for head-on and parasitic collisions (in the strong-strong sense), beam transport, statistics gathering, harmonic analysis, and periodic output of simulation data. The scale of this problem, once we go beyond the simplest case of a pair of bunches interacting once per turn, quickly escalates into the parallel computing arena, and herein we will describe the construction of an MPI-based version of COMBI able to utilize arbitrary numbers of processors to support efficient calculation of multi-bunch multi-IP interactions and transport. Implementing the parallel version did not require extensive disruption of the basic ...

  16. Seismic simulation analysis of nuclear reactor building by soil-building interaction model

    International Nuclear Information System (INIS)

    Muto, K.; Kobayashi, T.; Motohashi, S.; Kusano, N.; Mizuno, N.; Sugiyama, N.

    1981-01-01

    Seismic simulation analysis were performed for evaluating soil-structure interaction effects by an analytical approach using a 'Lattice Model' developed by the authors. The purpose of this paper is to check the adequacy of this procedure for analyzing soil-structure interaction by means of comparing computed results with recorded ones. The 'Lattice Model' approach employs a lumped mass interactive model, in which not only the structure but also the underlying and/or surrounding soil are modeled as descretized elements. The analytical model used for this study extends about 310 m in the horizontal direction and about 103 m in depth. The reactor building is modeled as three shearing-bending sticks (outer wall, inner wall and shield wall) and the underlying and surrounding soil are divided into four shearing sticks (column directly beneath the reactor building, adjacent, near and distant columns). A corresponding input base motion for the 'Lattice Model' was determined by a deconvolution analysis using a recorded motion at elevation -18.5 m in the free-field. The results of this simulation analysis were shown to be in reasonably good agreement with the recorded ones in the forms of the distribution of ground motions and structural responses, acceleration time histories and related response spectra. These results showed that the 'Lattice Model' approach was an appropriate one to estimate the soil-structure interaction effects. (orig./HP)

  17. Large Eddy simulations of flame/acoustics interactions in a swirl flow; Simulation aux grandes echelles des interactions flamme / acoustique dans un ecoulement vrille

    Energy Technology Data Exchange (ETDEWEB)

    Selle, L.

    2004-01-15

    Swirl flows exhibit a large variety of topologies, depending on the ratio of the flux axial momentum to the axial flux of tangential momentum: this ratio is called swirl number. Above a given critical value for the swirl number, the pressure gradient reverses the flow on the axis of rotation. This central recirculation zone is used in turbines for flame stabilization. And yet, reacting-swirled flows can exhibit combustion instabilities resulting from the coupling between acoustics and unsteady heat release. Combustion instabilities can lead to loss of control or even complete destruction of the system. Their prediction is impossible with standard engineering tools. The work presented here investigates the capabilities of numerical research tools for the prediction of combustion instabilities. Large-Eddy Simulation (LES) is implemented in a code solving the Navier-Stokes equations for compressible-multi-components fluids (code AVBP developed at CERFACS). This method takes into account for the major ingredients of combustion instabilities such as acoustics and flame / vortex interaction. The LES methodology is validated in the swirled flow from a complex industrial burner (SIEMENS PG). Both reactive and non-reactive regimes are successfully compared with experimental data in terms of mean temperature and mean and RMS velocities. Experimental measurements were performed at the university of Karlsruhe (Germany). A detailed analysis of the acoustics and its interaction with the flame front is performed with the code AVSP, also developed at CERFACS. (author)

  18. Event Generators for Simulating Heavy Ion Interactions of Interest in Evaluating Risks in Human Spaceflight

    Science.gov (United States)

    Wilson, Thomas L.; Pinsky, Lawrence; Andersen, Victor; Empl, Anton; Lee, Kerry; Smirmov, Georgi; Zapp, Neal; Ferrari, Alfredo; Tsoulou, Katerina; Roesler, Stefan; hide

    2005-01-01

    Simulating the Space Radiation environment with Monte Carlo Codes, such as FLUKA, requires the ability to model the interactions of heavy ions as they penetrate spacecraft and crew member's bodies. Monte-Carlo-type transport codes use total interaction cross sections to determine probabilistically when a particular type of interaction has occurred. Then, at that point, a distinct event generator is employed to determine separately the results of that interaction. The space radiation environment contains a full spectrum of radiation types, including relativistic nuclei, which are the most important component for the evaluation of crew doses. Interactions between incident protons with target nuclei in the spacecraft materials and crew member's bodies are well understood. However, the situation is substantially less comfortable for incident heavier nuclei (heavy ions). We have been engaged in developing several related heavy ion interaction models based on a Quantum Molecular Dynamics-type approach for energies up through about 5 GeV per nucleon (GeV/A) as part of a NASA Consortium that includes a parallel program of cross section measurements to guide and verify this code development.

  19. Emergence and frustration of magnetism with variable-range interactions in a quantum simulator.

    Science.gov (United States)

    Islam, R; Senko, C; Campbell, W C; Korenblit, S; Smith, J; Lee, A; Edwards, E E; Wang, C-C J; Freericks, J K; Monroe, C

    2013-05-03

    Frustration, or the competition between interacting components of a network, is often responsible for the emergent complexity of many-body systems. For instance, frustrated magnetism is a hallmark of poorly understood systems such as quantum spin liquids, spin glasses, and spin ices, whose ground states can be massively degenerate and carry high degrees of quantum entanglement. Here, we engineer frustrated antiferromagnetic interactions between spins stored in a crystal of up to 16 trapped (171)Yb(+) atoms. We control the amount of frustration by continuously tuning the range of interaction and directly measure spin correlation functions and their coherent dynamics. This prototypical quantum simulation points the way toward a new probe of frustrated quantum magnetism and perhaps the design of new quantum materials.

  20. Simulation Of Relativistic Hadronic Interactions In The Framework Of The Rts&t-2004 Code

    CERN Document Server

    Degtyarev, I I; Blokhin, A I; Liashenko, O A; Yazynin, I A

    2004-01-01

    The paper describes the current status of generalpurpose RTS&T (Radiation Transport Simulation and Isotopes Transmutation) multi-particles Monte Carlo radiation transport code [1]. New developments in modelling of discrete hadronic interactions (implementation of improved version for hA-interaction models and modern evaluated nuclear data libraries) are described. A comparison of the recent experimental data on double differential and total yields of diffractive, s, g and b-particles resulting from the high-energy hN- , hA- and AA-interactions is made with different semi-empirical and theoretical models of direct hadron production: data-driven model, parametrizationdriven model, intranuclear cascade model, quark-gluon string model, parton cascade model and quantum molecular dynamic model combined with generalized excitonevaporation (Fermi break-up)-fussion model to describe of slow particles and residual nuclei emission. The geometry presentation system and enhanced RTS&T-CAD-interface are described a...

  1. Fission product vapour - aerosol interactions in the containment: simulant fuel studies

    International Nuclear Information System (INIS)

    Beard, A.M.; Benson, C.G.; Bowsher, B.R.

    1988-12-01

    Experiments have been conducted in the Falcon facility to study the interaction of fission product vapours released from simulant fuel samples with control rod aerosols. The aerosols generated from both the control rod and fuel sample were chemically distinct and had different deposition characteristics. Extensive interaction was observed between the fission product vapours and the control rod aerosol. The two dominant mechanisms were condensation of the vapours onto the aerosol, and chemical reactions between the two components; sorption phenomena were believed to be only of secondary importance. The interaction of fission product vapours and reactor materials aerosols could have a major impact on the transport characteristics of the radioactive emission from a degrading core. (author)

  2. Computer simulation of biomolecule–biomaterial interactions at surfaces and interfaces

    International Nuclear Information System (INIS)

    Wang, Qun; Wang, Meng-hao; Lu, Xiong; Wang, Ke-feng; Zhang, Xing-dong; Liu, Yaling; Zhang, Hong-ping

    2015-01-01

    Biomaterial surfaces and interfaces are intrinsically complicated systems because they involve biomolecules, implanted biomaterials, and complex biological environments. It is difficult to understand the interaction mechanism between biomaterials and biomolecules through conventional experimental methods. Computer simulation is an effective way to study the interaction mechanism at the atomic and molecular levels. In this review, we summarized the recent studies on the interaction behaviors of biomolecules with three types of the most widely used biomaterials: hydroxyapatite (HA), titanium oxide (TiO 2 ), and graphene(G)/graphene oxide(GO). The effects of crystal forms, crystallographic planes, surface defects, doping atoms, and water environments on biomolecules adsorption are discussed in detail. This review provides valuable theoretical guidance for biomaterial designing and surface modification. (topical review)

  3. Aacsfi-PSC. Advanced accelerator concepts for strong field interaction simulated with the Plasma-Simulation-Code

    Energy Technology Data Exchange (ETDEWEB)

    Ruhl, Hartmut [Munich Univ. (Germany). Chair for Computational and Plasma Physics

    2016-11-01

    Since the installation of SuperMUC phase 2 the 9216 nodes of phase 1 are more easily available for large scale runs allowing for the thin foil and AWAKE simulations. Besides phase 2 could be used in parallel for high throughput of the ion acceleration simulations. Challenging to our project were the full-volume checkpoints required by PIC that strained the I/O-subsystem of SuperMUC to its limits. New approaches considered for the next generation system, like burst buffers could overcome this bottleneck. Additionally, as the FDTD solver in PIC is strongly bandwidth bound, PSC will benefit profoundly from high-bandwidth memory (HBM) that most likely will be available in future HPC machines. This will be of great advantage as in 2018 phase II of AWAKE should begin, with a longer plasma channel further increasing the need for additional computing resources. Last but not least, it is expected that our methods used in plasma physics (many body interaction with radiation) will be more and more adapted for medical diagnostics and treatments. For this research field we expect centimeter sized volumes with necessary resolutions of tens of micro meters resulting in boxes of >10{sup 12} voxels (100-200 TB) on a regular basis. In consequence the demand for computing time and especially for data storage and data handling capacities will also increase significantly.

  4. SIPSON--simulation of interaction between pipe flow and surface overland flow in networks.

    Science.gov (United States)

    Djordjević, S; Prodanović, D; Maksimović, C; Ivetić, M; Savić, D

    2005-01-01

    The new simulation model, named SIPSON, based on the Preissmann finite difference method and the conjugate gradient method, is presented in the paper. This model simulates conditions when the hydraulic capacity of a sewer system is exceeded, pipe flow is pressurized, the water flows out from the piped system to the streets, and the inlets cannot capture all the runoff. In the mathematical model, buried structures and pipelines, together with surface channels, make a horizontally and vertically looped network involving a complex interaction of flows. In this paper, special internal boundary conditions related to equivalent inlets are discussed. Procedures are described for the simulation of manhole cover loss, basement flooding, the representation of street geometry, and the distribution of runoff hydrographs between surface and underground networks. All these procedures are built into the simulation model. Relevant issues are illustrated on a set of examples, focusing on specific parameters and comparison with field measurements of flooding of the Motilal ki Chal catchment (Indore, India). Satisfactory agreement of observed and simulated hydrographs and maximum surface flooding levels is obtained. It is concluded that the presented approach is an improvement compared to the standard "virtual reservoir" approach commonly applied in most of the models.

  5. Natural interfaces for interacting with a virtual control desk of a nuclear power plant simulator

    International Nuclear Information System (INIS)

    Aghina, Mauricio Alves da Cunha e

    2012-01-01

    Due to very strict standards of safe operation of a nuclear power plant operators must be well trained so they can operate it within the necessary safety procedures. This is done through training simulators, which enable the user operation, as close as possible to the real control desk, and can be inserted accident situations, so they train, how to return the plant to a normal operating condition. Normally is used two types of simulator. Preferred is the full scope simulator, what is a computational dynamics program of the plant used in conjunction with a physical replica of the control desk, but this type of simulator involves a high construction cost. The second type is what uses synoptic windows of various regions of the original control desk, its construction cost is smaller, but it have a little fidelity to the original appearance of the table. Currently, with the use of virtual reality, control desks can be modeled in 3D, making the simulator interface is very similar to the appearance of the real control desk with a low cost construction. This work shows the use of natural interfaces for operator interaction with the virtual control desk, in order that it does not use any mechanical device for displaying and acting with it. For procedures that were used, such as: computer vision to recognize the position of the operator's and observation of their hands to the work of the desk controls and voice recognition. (author)

  6. Students' interaction for enhancing learning motivation and learning success: findings from integrating a simulation game into a university course

    OpenAIRE

    Otto, Daniel

    2017-01-01

    In recent decades, a vast amount of literature has been published discussing the educational use of simulation games in higher education. Since their emergence in the 1960s, simulation games have had a substantial effect on the way we think about teaching and learning in higher education. One reason simulation games are regarded as superior to traditional teaching is that they encourage students to interact and collaborate. Simulation games can therefore be subsumed under Kolbs learning model...

  7. Brownian dynamics simulations of polyelectrolyte adsorption in shear flow with hydrodynamic interaction

    Science.gov (United States)

    Hoda, Nazish; Kumar, Satish

    2007-12-01

    The adsorption of single polyelectrolyte molecules in shear flow is studied using Brownian dynamics simulations with hydrodynamic interaction (HI). Simulations are performed with bead-rod and bead-spring chains, and electrostatic interactions are incorporated through a screened Coulombic potential with excluded volume accounted for by the repulsive part of a Lennard-Jones potential. A correction to the Rotne-Prager-Yamakawa tensor is derived that accounts for the presence of a planar wall. The simulations show that migration away from an uncharged wall, which is due to bead-wall HI, is enhanced by increases in the strength of flow and intrachain electrostatic repulsion, consistent with kinetic theory predictions. When the wall and polyelectrolyte are oppositely charged, chain behavior depends on the strength of electrostatic screening. For strong screening, chains get depleted from a region close to the wall and the thickness of this depletion layer scales as N1/3Wi2/3 at high Wi, where N is the chain length and Wi is the Weissenberg number. At intermediate screening, bead-wall electrostatic attraction competes with bead-wall HI, and it is found that there is a critical Weissenberg number for desorption which scales as N-1/2κ-3(lB∣σq∣)3/2, where κ is the inverse screening length, lB is the Bjerrum length, σ is the surface charge density, and q is the bead charge. When the screening is weak, adsorbed chains are observed to align in the vorticity direction at low shear rates due to the effects of repulsive intramolecular interactions. At higher shear rates, the chains align in the flow direction. The simulation method and results of this work are expected to be useful for a number of applications in biophysics and materials science in which polyelectrolyte adsorption plays a key role.

  8. Effects of non-adiabatic walls on shock/boundary-layer interaction using direct numerical simulations

    Science.gov (United States)

    Volpiani, Pedro S.; Bernardini, Matteo; Larsson, Johan

    2017-11-01

    The influence of wall thermal conditions on the properties of an impinging shock wave interacting with a turbulent supersonic boundary layer is a research topic that still remains underexplored. In the present study, direct numerical simulations (DNS) are employed to investigate the flow properties of a shock wave interacting with a turbulent boundary layer at free-stream Mach number M∞ = 2.28 with distinct wall thermal conditions and shock strengths. Instantaneous and mean flow fields, wall quantities and the low-frequency unsteadiness are analyzed. While heating contributes to increase the extent of the interaction zone, wall cooling turns out to be a good candidate for flow control. The distribution of the Stanton number shows a good agreement with prior experimental studies and confirms the strong heat transfer and complex pattern within the interaction region. Numerical results indicate that the changes in the interaction length are mainly linked to the incoming boundary layer as suggested in previous studies (Souverein et al., 2013 and Jaunet et al., 2014). This work was supported by the Air Force Office of Scientific Research, Grant FA95501610385.

  9. Comparison between simulation and experimentally observed interactions between two magnetic beads in a fluidic system

    Energy Technology Data Exchange (ETDEWEB)

    Oduwole, Olayinka, E-mail: olayinka.oduwole@eng.ox.ac.uk; Grob, David Tim, E-mail: tim.grob@eng.ox.ac.uk; Sheard, Steve, E-mail: steve.sheard@eng.ox.ac.uk

    2016-06-01

    Continuous flow separation of magnetic particles within a microfluidic device could lead to improved performance of magnetic bead-based assays but the undesirable formation of bead clusters reduces its efficiency; this efficiency refers to the ability to separate bound magnetic beads from a mixture of particles. Such agglomerates are formed due to magnetic binding forces while hydrodynamic interactions strongly influence the particles' movement. This paper presents a model for interactions between a pair of equal sized super-paramagnetic beads suspended in water within a uniform magnetic field. To the best of our knowledge, we present for the first time a comparison between simulated trajectories and the beads' movement captured on video; the beads were suspended in a stationary fluid placed within a uniform magnetic field. In conclusion, the model is a good approximation for beads interacting with their nearest neighbours and is able to predict the trajectory pattern of these particles in a magnetic bead-based assay. Predicting the magnetically induced interaction of nearby beads will help in determining the density of beads in an assay and in avoiding agglomeration over a fixed time duration. - Highlights: • We modelled the interactions between a pair of super-paramagnetic beads suspended in water within a uniform magnetic field. • We tracked the movement of the bead pair and captured it on video. • We compared the numerical results with the video data and achieved a good agreement. • We predicted the agglomeration time as a function of the separation distance.

  10. Cometary jets in interaction with the solar wind: a hybrid simulation study

    Science.gov (United States)

    Wiehle, Stefan; Motschmann, Uwe; Gortsas, Nikolaos; Mueller, Joachim; Kriegel, Hendrik; Koenders, Christoph; Glassmeier, Karl-Heinz

    The effect of a cometary jet on the solar wind interaction is studied using comet 67P/Churyumov-Gerasimenko as case study. This comet is the target of the Rosetta-mission which will arrive in 2014. Observations suggest that cometary outgassing is confined to only a few percent of the cometary surface; thus, the measurement of jets is expected. Most former comet simulations did not attend to this fact and used an isotropic outgassing scheme or simplified outgassing patterns. Here, a single sun-facing jet is set to be the only source of cometary gas produc-tion. Using an analytic profile, this outgassing jet was implemented in a hybrid simulation code which treats protons and cometary heavy ions as particles and electrons as massless fluid. In a simulation series, the geometric parameters of the jet were varied to study the effect of different opening angles while the integrated outgassing rate remained constant. It was shown that the resulting solar wind interaction is highly dependent on the geometry of the jet. The plasma-structures like the solar wind pile-up found in the situation with isotropic outgassing are moved more and more sunward as the opening angle of the jet decreases. Furthermore, the cometary ion tail shows some kind of splitting which is not known from isotropic models.

  11. Fluid-structure interaction dynamic simulation of spring-loaded pressure relief valves under seismic wave

    Science.gov (United States)

    Lv, Dongwei; Zhang, Jian; Yu, Xinhai

    2018-05-01

    In this paper, a fluid-structure interaction dynamic simulation method of spring-loaded pressure relief valve was established. The dynamic performances of the fluid regions and the stress and strain of the structure regions were calculated at the same time by accurately setting up the contact pairs between the solid parts and the coupling surfaces between the fluid regions and the structure regions. A two way fluid-structure interaction dynamic simulation of a simplified pressure relief valve model was carried out. The influence of vertical sinusoidal seismic waves on the performance of the pressure relief valve was preliminarily investigated by loading sine waves. Under vertical seismic waves, the pressure relief valve will flutter, and the reseating pressure was affected by the amplitude and frequency of the seismic waves. This simulation method of the pressure relief valve under vertical seismic waves can provide effective means for investigating the seismic performances of the valves, and make up for the shortcomings of the experiment.

  12. An operator training simulator based on interactive virtual teleoperation: nuclear facilities maintenance applications

    International Nuclear Information System (INIS)

    Kim, Ki Ho; Kim, Seung Ho

    1997-01-01

    Remote manipulation in nuclear hazardous environment is very often complex and difficult to operate and requires excessively careful preparation. Remote slave manipulators for unstructured work are manually controlled by a human operator. Small errors made by the operator via the master manipulator during operation can cause the slave to be surffered from excessive forces and result in considerable damages to the slave iteself and its environment. In this paper, we present a prototype of an operator training simulator for use in nuclear facilities maintenance applications, as part of the ongoing Nuclear Robotics Development Program at Korea Atomic Energy Research Institute (KAERI). The operator training simulator provides a means by which, in virtual task simulation, the operator can try out and train for expected remote tasks that the real slave manipulator will perform in advance. The operator interacts with both the virtual slave and task environment through the real master. Virtual interaction force feedback is provided to the operator. We also describe a man-in-the loop control scheme to realize bilateral force reflection in virtual teleoperation

  13. Earthquake simulations with time-dependent nucleation and long-range interactions

    Directory of Open Access Journals (Sweden)

    J. H. Dieterich

    1995-01-01

    Full Text Available A model for rapid simulation of earthquake sequences is introduced which incorporates long-range elastic interactions among fault elements and time-dependent earthquake nucleation inferred from experimentally derived rate- and state-dependent fault constitutive properties. The model consists of a planar two-dimensional fault surface which is periodic in both the x- and y-directions. Elastic interactions among fault elements are represented by an array of elastic dislocations. Approximate solutions for earthquake nucleation and dynamics of earthquake slip are introduced which permit computations to proceed in steps that are determined by the transitions from one sliding state to the next. The transition-driven time stepping and avoidance of systems of simultaneous equations permit rapid simulation of large sequences of earthquake events on computers of modest capacity, while preserving characteristics of the nucleation and rupture propagation processes evident in more detailed models. Earthquakes simulated with this model reproduce many of the observed spatial and temporal characteristics of clustering phenomena including foreshock and aftershock sequences. Clustering arises because the time dependence of the nucleation process is highly sensitive to stress perturbations caused by nearby earthquakes. Rate of earthquake activity following a prior earthquake decays according to Omori's aftershock decay law and falls off with distance.

  14. Modelling and simulation of dynamic wheel-rail interaction using a roller rig

    International Nuclear Information System (INIS)

    Anyakwo, A; Pislaru, C; Ball, A; Gu, F

    2012-01-01

    The interaction between the wheel and rail greatly influences the dynamic response of railway vehicles on the track. A roller rig facility can be used to study and monitor real time parameters that influence wheel-rail interaction such as wear, adhesion, friction and corrugation without actual field tests being carried out. This paper presents the development of the mathematical models for full scale roller rig and 1/5 scale roller rig and the wear prediction model based on KTH wear function. The simulated critical speed for the 1/5 scale roller rig is about one-fifth of the critical speed for the full scale model so the simulated results compare well with the theory related to wheel-rail contact and dynamics. Also the differences between the simulated rolling radii for the full scale model with and without wear function are analysed. This paper presents the initial stage of a large scale research project where the influence of wear on the wheel-rail performance will be studied in more depth.

  15. Simulation of water-rock interaction in the yellowstone geothermal system using TOUGHREACT

    International Nuclear Information System (INIS)

    Dobson, P.F.; Salah, S.; Spycher, N.; Sonnenthal, E.

    2003-01-01

    The Yellowstone geothermal system provides an ideal opportunity to test the ability of reactive transport models to accurately simulate water-rock interaction. Previous studies of the Yellowstone geothermal system have characterized water-rock interaction through analysis of rocks and fluids obtained from both surface and downhole samples. Fluid chemistry, rock mineralogy, permeability, porosity, and thermal data obtained from the Y-8 borehole in Upper Geyser Basin were used to constrain a series of reactive transport simulations of the Yellowstone geothermal system using TOUGHREACT. Three distinct stratigraphic units were encountered in the 153.4 m deep Y-8 drill core: volcaniclastic sandstone, perlitic rhyolitic lava, and nonwelded pumiceous tuff. The main alteration phases identified in the Y-8 core samples include clay minerals, zeolites, silica polymorphs, adularia, and calcite. Temperatures observed in the Y-8 borehole increase with depth from sub-boiling conditions at the surface to a maximum of 169.8 C at a depth of 104.1 m, with near-isothermal conditions persisting down to the well bottom. 1-D models of the Y-8 core hole were constructed to determine if TOUGHREACT could accurately predict the observed alteration mineral assemblage given the initial rock mineralogy and observed fluid chemistry and temperatures. Preliminary simulations involving the perlitic rhyolitic lava unit are consistent with the observed alteration of rhyolitic glass to form celadonite

  16. The selective interaction between silica nanoparticles and enzymes from molecular dynamics simulations.

    Directory of Open Access Journals (Sweden)

    Xiaotian Sun

    Full Text Available Nanoscale particles have become promising materials in many fields, such as cancer therapeutics, diagnosis, imaging, drug delivery, catalysis, as well as biosensors. In order to stimulate and facilitate these applications, there is an urgent need for the understanding of the interaction mode between the nano-particles and proteins. In this study, we investigate the orientation and adsorption between several enzymes (cytochrome c, RNase A, lysozyme and 4 nm/11 nm silica nanoparticles (SNPs by using molecular dynamics (MD simulation. Our results show that three enzymes are adsorbed onto the surfaces of both 4 nm and 11 nm SNPs during our MD simulations and the small SNPs induce greater structural stabilization. The active site of cytochrome c is far away from the surface of 4 nm SNPs, while it is adsorbed onto the surface of 11 nm SNPs. We also explore the influences of different groups (-OH, -COOH, -NH2 and CH3 coated onto silica nanoparticles, which show significantly different impacts. Our molecular dynamics results indicate the selective interaction between silicon nanoparticles and enzymes, which is consistent with experimental results. Our study provides useful guides for designing/modifying nanomaterials to interact with proteins for their bio-applications.

  17. Interactive simulations of gas-turbine modular HTGR transients and heatup accidents

    International Nuclear Information System (INIS)

    Ball, S.J.; Nypaver, D.J.

    1994-01-01

    An interactive workstation-based simulator has been developed for performing analyses of modular high-temperature gas-cooled reactor (MHTGR) core transients and accidents. It was originally developed at Oak Ridge National Laboratory for the US Nuclear Regulatory Commission to assess the licensability of the US Department of Energy (DOE) steam cycle design 350-MW(t) MHTGR. Subsequently, the code was modified under DOE sponsorship to simulate the 450-MW(t) Gas Turbine (GT) design and to aid in development and design studies. Features of the code (MORECA-GT) include detailed modeling of 3-D core thermal-hydraulics, interactive workstation capabilities that allow user/analyst or ''operator'' involvement in accident scenarios, and options for studying anticipated transients without scram (ATWS) events. In addition to the detailed models for the core, MORECA includes models for the vessel, Shutdown Cooling System (SCS), and Reactor Cavity Cooling System (RCCS), and core point kinetics to accommodate ATWS events. The balance of plant (BOP) is currently not modeled. The interactive workstation features include options for on-line parameter plots and 3-D graphic temperature profiling. The studies to date show that the proposed MHTGR designs are very robust and can generally withstand the consequences of even the extremely low probability postulated accidents with little or no damage to the reactor's fuel or metallic components

  18. Modeling of fatigue crack induced nonlinear ultrasonics using a highly parallelized explicit local interaction simulation approach

    Science.gov (United States)

    Shen, Yanfeng; Cesnik, Carlos E. S.

    2016-04-01

    This paper presents a parallelized modeling technique for the efficient simulation of nonlinear ultrasonics introduced by the wave interaction with fatigue cracks. The elastodynamic wave equations with contact effects are formulated using an explicit Local Interaction Simulation Approach (LISA). The LISA formulation is extended to capture the contact-impact phenomena during the wave damage interaction based on the penalty method. A Coulomb friction model is integrated into the computation procedure to capture the stick-slip contact shear motion. The LISA procedure is coded using the Compute Unified Device Architecture (CUDA), which enables the highly parallelized supercomputing on powerful graphic cards. Both the explicit contact formulation and the parallel feature facilitates LISA's superb computational efficiency over the conventional finite element method (FEM). The theoretical formulations based on the penalty method is introduced and a guideline for the proper choice of the contact stiffness is given. The convergence behavior of the solution under various contact stiffness values is examined. A numerical benchmark problem is used to investigate the new LISA formulation and results are compared with a conventional contact finite element solution. Various nonlinear ultrasonic phenomena are successfully captured using this contact LISA formulation, including the generation of nonlinear higher harmonic responses. Nonlinear mode conversion of guided waves at fatigue cracks is also studied.

  19. Multilevel summation with B-spline interpolation for pairwise interactions in molecular dynamics simulations

    International Nuclear Information System (INIS)

    Hardy, David J.; Schulten, Klaus; Wolff, Matthew A.; Skeel, Robert D.; Xia, Jianlin

    2016-01-01

    The multilevel summation method for calculating electrostatic interactions in molecular dynamics simulations constructs an approximation to a pairwise interaction kernel and its gradient, which can be evaluated at a cost that scales linearly with the number of atoms. The method smoothly splits the kernel into a sum of partial kernels of increasing range and decreasing variability with the longer-range parts interpolated from grids of increasing coarseness. Multilevel summation is especially appropriate in the context of dynamics and minimization, because it can produce continuous gradients. This article explores the use of B-splines to increase the accuracy of the multilevel summation method (for nonperiodic boundaries) without incurring additional computation other than a preprocessing step (whose cost also scales linearly). To obtain accurate results efficiently involves technical difficulties, which are overcome by a novel preprocessing algorithm. Numerical experiments demonstrate that the resulting method offers substantial improvements in accuracy and that its performance is competitive with an implementation of the fast multipole method in general and markedly better for Hamiltonian formulations of molecular dynamics. The improvement is great enough to establish multilevel summation as a serious contender for calculating pairwise interactions in molecular dynamics simulations. In particular, the method appears to be uniquely capable for molecular dynamics in two situations, nonperiodic boundary conditions and massively parallel computation, where the fast Fourier transform employed in the particle–mesh Ewald method falls short.

  20. 3D FE simulation of PCMI (Pellet-Cladding Mechanical Interaction) considering frictionless contact

    International Nuclear Information System (INIS)

    Seo, Sang-Kyu; Lee, Sung-Uk; Lee, Eun-Ho; Yang, Dong-Yol; Kim, Hyo-Chan; Yang, Yong-Sik

    2014-01-01

    The goal of this code is coupling every aspect of physical phenomenon. Monodimensional FE model has been made for METEOR. It is good to evaluate the global behavior in high burn up levels. However, the multi-dimensional PCI analysis code is necessary to precisely analyze the stress distribution especially in case of the crack analysis. CAST3M 3D finite element code has been developed considering thermo-mechanical interaction in detail for TOUTATIS code. The advanced multidimensional code called ALCYONE has been developed considering chemical-physics and thermomechanical aspects. Although there are many codes that analyze pellet and cladding interaction, it is difficult to consider every physical aspect. In this paper, pellet to cladding mechanical interaction in 3D has been simulated with frictionless contact using the developed module, which is written in FORTRANN90. In this paper, 3D PCMI FE model is simulated with frictionless contact and elastic deformation. From the frictionless contact analysis, the interfacial pressure has been calculated and then this is used to obtain the solid heat coefficient which is a main factor to analyze the thermal distribution

  1. Chitosan nanoparticles-trypsin interactions: Bio-physicochemical and molecular dynamics simulation studies.

    Science.gov (United States)

    Salar, Safoura; Mehrnejad, Faramarz; Sajedi, Reza H; Arough, Javad Mohammadnejad

    2017-10-01

    Herein, we investigated the effect of the chitosan nanoparticles (CsNP) on the structure, dynamics, and activity of trypsin. The enzyme activity in complex with the nanoparticles slightly increased, which represents the interactions between the nanoparticles and the enzyme. The kinetic parameters of the enzyme, K m and k cat , increased after adding the nanoparticles, resulting in a slight increase in the catalytic efficiency (k cat /K m ). However, the effect of the nanoparticles on the kinetic stability of trypsin has not exhibited significant variations. Fluorescence spectroscopy did not show remarkable changes in the trypsin conformation in the presence of the nanoparticles. The circular dichroism (CD) spectroscopy results also revealed the secondary structure of trypsin attached to the nanoparticles slightly changed. Furthermore, we used molecular dynamics (MD) simulation to find more information about the interaction mechanisms between the nanoparticles and trypsin. The root mean square deviation (RMSD) of Cα atoms results have shown that in the presence of the nanoparticles, trypsin was stable. The simulation and the calculation of the binding free energy demonstrate that the nonpolar interactions are the most important forces for the formation of stable nanoparticle-trypsin complex. This study has explicitly elucidated that the nanoparticles have not considerable effect on the trypsin. Copyright © 2017. Published by Elsevier B.V.

  2. [Simulating measles and rubella elimination levels according to social stratification and interaction].

    Science.gov (United States)

    Hincapié-Palacio, Doracelly; Ospina-Giraldo, Juan; Gómez-Arias, Rubén D; Uyi-Afuwape, Anthony; Chowell-Puente, Gerardo

    2010-02-01

    The study was aimed at comparing measles and rubella disease elimination levels in a homogeneous and heterogeneous population according to socioeconomic status with interactions amongst low- and high-income individuals and diversity in the average number of contacts amongst them. Effective reproductive rate simulations were deduced from a susceptibleinfected- recovered (SIR) mathematical model according to different immunisation rates using measles (1980 and 2005) and rubella (1998 and 2005) incidence data from Latin-America and the Caribbean. Low- and high-income individuals' social interaction and their average number of contacts were analysed by bipartite random network analysis. MAPLE 12 (Maplesoft Inc, Ontario Canada) software was used for making the simulations. The progress made in eliminating both diseases between both periods of time was reproduced in the socially-homogeneous population. Measles (2005) would be eliminated in high- and low-income groups; however, it would only be achieved in rubella (2005) if there were a high immunity rate amongst the low-income group. If the average number of contacts were varied, then rubella would not be eliminated, even with a 95 % immunity rate. Monitoring the elimination level in diseases like measles and rubella requires that socio-economic status be considered as well as the population's interaction pattern. Special attention should be paid to communities having diversity in their average number of contacts occurring in confined spaces such as displaced communities, prisons, educational establishments, or hospitals.

  3. Interactive simulations of gas-turbine modular HTGR transients and heatup accidents

    Energy Technology Data Exchange (ETDEWEB)

    Ball, S.J.; Nypaver, D.J.

    1994-06-01

    An interactive workstation-based simulator has been developed for performing analyses of modular high-temperature gas-cooled reactor (MHTGR) core transients and accidents. It was originally developed at Oak Ridge National Laboratory for the US Nuclear Regulatory Commission to assess the licensability of the US Department of Energy (DOE) steam cycle design 350-MW(t) MHTGR. Subsequently, the code was modified under DOE sponsorship to simulate the 450-MW(t) Gas Turbine (GT) design and to aid in development and design studies. Features of the code (MORECA-GT) include detailed modeling of 3-D core thermal-hydraulics, interactive workstation capabilities that allow user/analyst or ``operator`` involvement in accident scenarios, and options for studying anticipated transients without scram (ATWS) events. In addition to the detailed models for the core, MORECA includes models for the vessel, Shutdown Cooling System (SCS), and Reactor Cavity Cooling System (RCCS), and core point kinetics to accommodate ATWS events. The balance of plant (BOP) is currently not modeled. The interactive workstation features include options for on-line parameter plots and 3-D graphic temperature profiling. The studies to date show that the proposed MHTGR designs are very robust and can generally withstand the consequences of even the extremely low probability postulated accidents with little or no damage to the reactor`s fuel or metallic components.

  4. A simulation study of gene-by-environment interactions in GWAS implies ample hidden effects

    Science.gov (United States)

    Marigorta, Urko M.; Gibson, Greg

    2014-01-01

    The switch to a modern lifestyle in recent decades has coincided with a rapid increase in prevalence of obesity and other diseases. These shifts in prevalence could be explained by the release of genetic susceptibility for disease in the form of gene-by-environment (GxE) interactions. Yet, the detection of interaction effects requires large sample sizes, little replication has been reported, and a few studies have demonstrated environmental effects only after summing the risk of GWAS alleles into genetic risk scores (GRSxE). We performed extensive simulations of a quantitative trait controlled by 2500 causal variants to inspect the feasibility to detect gene-by-environment interactions in the context of GWAS. The simulated individuals were assigned either to an ancestral or a modern setting that alters the phenotype by increasing the effect size by 1.05–2-fold at a varying fraction of perturbed SNPs (from 1 to 20%). We report two main results. First, for a wide range of realistic scenarios, highly significant GRSxE is detected despite the absence of individual genotype GxE evidence at the contributing loci. Second, an increase in phenotypic variance after environmental perturbation reduces the power to discover susceptibility variants by GWAS in mixed cohorts with individuals from both ancestral and modern environments. We conclude that a pervasive presence of gene-by-environment effects can remain hidden even though it contributes to the genetic architecture of complex traits. PMID:25101110

  5. Hydrodynamical simulations of the stream-core interaction in the slow merger of massive stars

    Science.gov (United States)

    Ivanova, N.; Podsiadlowski, Ph.; Spruit, H.

    2002-08-01

    We present detailed simulations of the interaction of a stream emanating from a mass-losing secondary with the core of a massive supergiant in the slow merger of two stars inside a common envelope. The dynamics of the stream can be divided into a ballistic phase, starting at the L1 point, and a hydrodynamical phase, where the stream interacts strongly with the core. Considering the merger of a 1- and 5-Msolar star with a 20-Msolar evolved supergiant, we present two-dimensional hydrodynamical simulations using the PROMETHEUS code to demonstrate how the penetration depth and post-impact conditions depend on the initial properties of the stream material (e.g. entropy, angular momentum, stream width) and the properties of the core (e.g. density structure and rotation rate). Using these results, we present a fitting formula for the entropy generated in the stream-core interaction and a recipe for the determination of the penetration depth based on a modified Bernoulli integral.

  6. Molecular dynamics simulations of the DNA interaction with metallic nanoparticles and TiO2 surfaces

    International Nuclear Information System (INIS)

    Kholmurodov, Kh.T.; Krasavin, E.A.; Dushanov, E.B.; Hassan, H.K.; Galal, A.; ElHabashy, H.A.; Sweilam, N.H.; Yasuoka, K.

    2013-01-01

    The understanding of the mechanism of DNA interactions and binding with metallic nanoparticles (NPs) and surfaces represents a great interest in today's medicine applications due to diagnostic and treatment of oncology diseases. Recent experimental and simulation studies involve the DNA interaction with highly localized proton beams or metallic NPs (such as Ag, Au, etc.), aimed at targeted cancer therapy through the injection of metal micro- or nanoparticles into the tumor tissue with consequent local microwave or laser heating. The effects of mutational structure changes in DNA and protein structures could result in destroying of native chemical (hydrogen) bonds or, on the contrary, creating of new bonds that do not normally exist there. The cause of such changes might be the alteration of one or several nucleotides (in DNA) or the substitution of specific amino acid residues (in proteins) that can lead to the essential structural destabilization or unfolding. At the atomic or molecular level, the replacement of one nucleotide by another (in DNA double helices) or replacement of one amino acid residue by another (in proteins) cause essential modifications of the molecular force fields of the environment that break locally important hydrogen bonds underlying the structural stability of the biological molecules. In this work, the molecular dynamics(MD) simulations were performed for four DNA models and the flexibilities of the purine and pyrimidine nucleotides during the interaction process with the metallic NPs and TiO 2 surface were clarified

  7. A hybrid parallel architecture for electrostatic interactions in the simulation of dissipative particle dynamics

    Science.gov (United States)

    Yang, Sheng-Chun; Lu, Zhong-Yuan; Qian, Hu-Jun; Wang, Yong-Lei; Han, Jie-Ping

    2017-11-01

    In this work, we upgraded the electrostatic interaction method of CU-ENUF (Yang, et al., 2016) which first applied CUNFFT (nonequispaced Fourier transforms based on CUDA) to the reciprocal-space electrostatic computation and made the computation of electrostatic interaction done thoroughly in GPU. The upgraded edition of CU-ENUF runs concurrently in a hybrid parallel way that enables the computation parallelizing on multiple computer nodes firstly, then further on the installed GPU in each computer. By this parallel strategy, the size of simulation system will be never restricted to the throughput of a single CPU or GPU. The most critical technical problem is how to parallelize a CUNFFT in the parallel strategy, which is conquered effectively by deep-seated research of basic principles and some algorithm skills. Furthermore, the upgraded method is capable of computing electrostatic interactions for both the atomistic molecular dynamics (MD) and the dissipative particle dynamics (DPD). Finally, the benchmarks conducted for validation and performance indicate that the upgraded method is able to not only present a good precision when setting suitable parameters, but also give an efficient way to compute electrostatic interactions for huge simulation systems. Program Files doi:http://dx.doi.org/10.17632/zncf24fhpv.1 Licensing provisions: GNU General Public License 3 (GPL) Programming language: C, C++, and CUDA C Supplementary material: The program is designed for effective electrostatic interactions of large-scale simulation systems, which runs on particular computers equipped with NVIDIA GPUs. It has been tested on (a) single computer node with Intel(R) Core(TM) i7-3770@ 3.40 GHz (CPU) and GTX 980 Ti (GPU), and (b) MPI parallel computer nodes with the same configurations. Nature of problem: For molecular dynamics simulation, the electrostatic interaction is the most time-consuming computation because of its long-range feature and slow convergence in simulation space

  8. Winter Frost and Fog

    Science.gov (United States)

    2005-01-01

    This somewhat oblique blue wide angle Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows the 174 km (108 mi) diameter crater, Terby, and its vicinity in December 2004. Located north of Hellas, this region can be covered with seasonal frost and ground-hugging fog, even in the afternoon, despite being north of 30oS. The subtle, wavy pattern is a manifestation of fog. Location near: 28oS, 286oW Illumination from: upper left Season: Southern Winter

  9. Developing an interactive computational system to simulate radon concentration inside ancient egyptian tombs

    Energy Technology Data Exchange (ETDEWEB)

    Metwally, S M; Salama, E; El-Fikia, S A [Faculty of Science, Department of Physics, Ain Shams University, P. O. Box 11566, Cairo (Egypt); Abo-EImagd, M; Eissa, H M [National Institute for Standard, Radiation Measurements Department, P. O. Box 136Giza code no. 12211 RSSP (Egypt)

    2007-06-15

    RSSP (Radon Scale Software Package) is an interactive support system that simulates the radon concentration inside ancient Egyptian tombs and the consequences on the population in terms of internal and external exposure. RSSP consists of three interconnected modules: the first one simulates the radon concentration inside ancient Egyptian tombs using a developed mathematical model. This model introduces the possibility of controlling the rate of radon accumulation via additional artificial ventilation systems. The source of inputs is an editable database for the tombs includes the geometrical dimensions and some environmental parameters like temperature and outdoor radon concentration at the tombs locations. The second module simulates the absorbed dose due to internal exposure of radon and its progeny. The third module simulates the absorbed dose due to external exposure of Gamma rays emitted from the tomb wall rocks. RSSP introduces the facility of following the progress of radon concentration as well as Internal and external absorbed dose in a wide range of time (seconds, minutes, hours and days) via numerical data and the corresponding graphical interface.

  10. Developing an interactive computational system to simulate radon concentration inside ancient egyptian tombs

    International Nuclear Information System (INIS)

    Metwally, S. M.; Salama, E.; El-Fikia, S. A.; Abo-EImagd, M.; Eissa, H. M.

    2007-01-01

    RSSP (Radon Scale Software Package) is an interactive support system that simulates the radon concentration inside ancient Egyptian tombs and the consequences on the population in terms of internal and external exposure. RSSP consists of three interconnected modules: the first one simulates the radon concentration inside ancient Egyptian tombs using a developed mathematical model. This model introduces the possibility of controlling the rate of radon accumulation via additional artificial ventilation systems. The source of inputs is an editable database for the tombs includes the geometrical dimensions and some environmental parameters like temperature and outdoor radon concentration at the tombs locations. The second module simulates the absorbed dose due to internal exposure of radon and its progeny. The third module simulates the absorbed dose due to external exposure of Gamma rays emitted from the tomb wall rocks. RSSP introduces the facility of following the progress of radon concentration as well as Internal and external absorbed dose in a wide range of time (seconds, minutes, hours and days) via numerical data and the corresponding graphical interface

  11. Coarse-grained stochastic processes and kinetic Monte Carlo simulators for the diffusion of interacting particles

    Science.gov (United States)

    Katsoulakis, Markos A.; Vlachos, Dionisios G.

    2003-11-01

    We derive a hierarchy of successively coarse-grained stochastic processes and associated coarse-grained Monte Carlo (CGMC) algorithms directly from the microscopic processes as approximations in larger length scales for the case of diffusion of interacting particles on a lattice. This hierarchy of models spans length scales between microscopic and mesoscopic, satisfies a detailed balance, and gives self-consistent fluctuation mechanisms whose noise is asymptotically identical to the microscopic MC. Rigorous, detailed asymptotics justify and clarify these connections. Gradient continuous time microscopic MC and CGMC simulations are compared under far from equilibrium conditions to illustrate the validity of our theory and delineate the errors obtained by rigorous asymptotics. Information theory estimates are employed for the first time to provide rigorous error estimates between the solutions of microscopic MC and CGMC, describing the loss of information during the coarse-graining process. Simulations under periodic boundary conditions are used to verify the information theory error estimates. It is shown that coarse-graining in space leads also to coarse-graining in time by q2, where q is the level of coarse-graining, and overcomes in part the hydrodynamic slowdown. Operation counting and CGMC simulations demonstrate significant CPU savings in continuous time MC simulations that vary from q3 for short potentials to q4 for long potentials. Finally, connections of the new coarse-grained stochastic processes to stochastic mesoscopic and Cahn-Hilliard-Cook models are made.

  12. Quantified, Interactive Simulation of AMCW ToF Camera Including Multipath Effects

    Directory of Open Access Journals (Sweden)

    David Bulczak

    2017-12-01

    Full Text Available In the last decade, Time-of-Flight (ToF range cameras have gained increasing popularity in robotics, automotive industry, and home entertainment. Despite technological developments, ToF cameras still suffer from error sources such as multipath interference or motion artifacts. Thus, simulation of ToF cameras, including these artifacts, is important to improve camera and algorithm development. This paper presents a physically-based, interactive simulation technique for amplitude modulated continuous wave (AMCW ToF cameras, which, among other error sources, includes single bounce indirect multipath interference based on an enhanced image-space approach. The simulation accounts for physical units down to the charge level accumulated in sensor pixels. Furthermore, we present the first quantified comparison for ToF camera simulators. We present bidirectional reference distribution function (BRDF measurements for selected, purchasable materials in the near-infrared (NIR range, craft real and synthetic scenes out of these materials and quantitatively compare the range sensor data.

  13. Nonlinear plasma wave models in 3D fluid simulations of laser-plasma interaction

    Science.gov (United States)

    Chapman, Thomas; Berger, Richard; Arrighi, Bill; Langer, Steve; Banks, Jeffrey; Brunner, Stephan

    2017-10-01

    Simulations of laser-plasma interaction (LPI) in inertial confinement fusion (ICF) conditions require multi-mm spatial scales due to the typical laser beam size and durations of order 100 ps in order for numerical laser reflectivities to converge. To be computationally achievable, these scales necessitate a fluid-like treatment of light and plasma waves with a spatial grid size on the order of the light wave length. Plasma waves experience many nonlinear phenomena not naturally described by a fluid treatment, such as frequency shifts induced by trapping, a nonlinear (typically suppressed) Landau damping, and mode couplings leading to instabilities that can cause the plasma wave to decay rapidly. These processes affect the onset and saturation of stimulated Raman and Brillouin scattering, and are of direct interest to the modeling and prediction of deleterious LPI in ICF. It is not currently computationally feasible to simulate these Debye length-scale phenomena in 3D across experimental scales. Analytically-derived and/or numerically benchmarked models of processes occurring at scales finer than the fluid simulation grid offer a path forward. We demonstrate the impact of a range of kinetic processes on plasma reflectivity via models included in the LPI simulation code pF3D. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  14. Novel 3D/VR interactive environment for MD simulations, visualization and analysis.

    Science.gov (United States)

    Doblack, Benjamin N; Allis, Tim; Dávila, Lilian P

    2014-12-18

    The increasing development of computing (hardware and software) in the last decades has impacted scientific research in many fields including materials science, biology, chemistry and physics among many others. A new computational system for the accurate and fast simulation and 3D/VR visualization of nanostructures is presented here, using the open-source molecular dynamics (MD) computer program LAMMPS. This alternative computational method uses modern graphics processors, NVIDIA CUDA technology and specialized scientific codes to overcome processing speed barriers common to traditional computing methods. In conjunction with a virtual reality system used to model materials, this enhancement allows the addition of accelerated MD simulation capability. The motivation is to provide a novel research environment which simultaneously allows visualization, simulation, modeling and analysis. The research goal is to investigate the structure and properties of inorganic nanostructures (e.g., silica glass nanosprings) under different conditions using this innovative computational system. The work presented outlines a description of the 3D/VR Visualization System and basic components, an overview of important considerations such as the physical environment, details on the setup and use of the novel system, a general procedure for the accelerated MD enhancement, technical information, and relevant remarks. The impact of this work is the creation of a unique computational system combining nanoscale materials simulation, visualization and interactivity in a virtual environment, which is both a research and teaching instrument at UC Merced.

  15. Mechanism of mRNA-STAR domain interaction: Molecular dynamics simulations of Mammalian Quaking STAR protein.

    Science.gov (United States)

    Sharma, Monika; Anirudh, C R

    2017-10-03

    STAR proteins are evolutionary conserved mRNA-binding proteins that post-transcriptionally regulate gene expression at all stages of RNA metabolism. These proteins possess conserved STAR domain that recognizes identical RNA regulatory elements as YUAAY. Recently reported crystal structures show that STAR domain is composed of N-terminal QUA1, K-homology domain (KH) and C-terminal QUA2, and mRNA binding is mediated by KH-QUA2 domain. Here, we present simulation studies done to investigate binding of mRNA to STAR protein, mammalian Quaking protein (QKI). We carried out conventional MD simulations of STAR domain in presence and absence of mRNA, and studied the impact of mRNA on the stability, dynamics and underlying allosteric mechanism of STAR domain. Our unbiased simulations results show that presence of mRNA stabilizes the overall STAR domain by reducing the structural deviations, correlating the 'within-domain' motions, and maintaining the native contacts information. Absence of mRNA not only influenced the essential modes of motion of STAR domain, but also affected the connectivity of networks within STAR domain. We further explored the dissociation of mRNA from STAR domain using umbrella sampling simulations, and the results suggest that mRNA binding to STAR domain occurs in multi-step: first conformational selection of mRNA backbone conformations, followed by induced fit mechanism as nucleobases interact with STAR domain.

  16. Interactive simulation of nuclear power systems using a dedicated minicomputer - computer graphics facility

    International Nuclear Information System (INIS)

    Tye, C.; Sezgen, A.O.

    1980-01-01

    The design of control systems and operational procedures for large scale nuclear power plant poses a difficult optimization problem requiring a lot of computational effort. Plant dynamic simulation using digital minicomputers offers the prospect of relatively low cost computing and when combined with graphical input/output provides a powerful tool for studying such problems. The paper discusses the results obtained from a simulation study carried out at the Computer Graphics Unit of the University of Manchester using a typical station control model for an Advanced Gas Cooled reactor. Particular reference is placed on the use of computer graphics for information display, parameter and control system optimization and techniques for using graphical input for defining and/or modifying the control system topology. Experience gained from this study has shown that a relatively modest minicomputer system can be used for simulating large scale dynamic systems and that highly interactive computer graphics can be used to advantage to relieve the designer of many of the tedious aspects of simulation leaving him free to concentrate on the more creative aspects of his work. (author)

  17. The simulation of man-machine interaction in NPPs: the system response analyser project

    International Nuclear Information System (INIS)

    Cacciabue, P.C.

    1990-01-01

    In this paper, the ongoing research at Joint Research Centre-Ispra on the simulation of man-machine interaction is reviewed with reference to the past experience of system modelling and to the advances of the technological world. These require the coalescence of mixed disciplines covering the fields of engineering, psychology and sociology. In particular, the complexity of man-machine systems with respect to safety analysis is depicted. The developments and issues in modelling humans and machines are discussed: the possibility of combining them through the System Response Analyser methodology is presented as a balanced to be applied when the objective is the study of safety of systems during abnormal sequences. The three analytical tools which constitute the body of system response analysis namely a quasi-classical simulation of the actual plant, a cognitive model of the operator activities and a driver model, are described. (author)

  18. Kinetic Simulations of Plasma Energization and Particle Acceleration in Interacting Magnetic Flux Ropes

    Science.gov (United States)

    Du, S.; Guo, F.; Zank, G. P.; Li, X.; Stanier, A.

    2017-12-01

    The interaction between magnetic flux ropes has been suggested as a process that leads to efficient plasma energization and particle acceleration (e.g., Drake et al. 2013; Zank et al. 2014). However, the underlying plasma dynamics and acceleration mechanisms are subject to examination of numerical simulations. As a first step of this effort, we carry out 2D fully kinetic simulations using the VPIC code to study the plasma energization and particle acceleration during coalescence of two magnetic flux ropes. Our analysis shows that the reconnection electric field and compression effect are important in plasma energization. The results may help understand the energization process associated with magnetic flux ropes frequently observed in the solar wind near the heliospheric current sheet.

  19. On the origin of the hydration interaction of LIPID bilayers from molecular dynamics simulations

    International Nuclear Information System (INIS)

    Essmann, U.; Perera, L.; Berkowitz, M.L.

    1996-01-01

    To understand the nature of the hydration forces acting between biomembranes we performed computer simulations on DLPE/water and DPPC/water systems in liquid crystalline and gel phases. The simulations show that the influence of the membrane surface on water properties is detectable only over a short range and that the membrane surfaces are rough on the molecular scale. We find that the hydration force is due to (a) the removal of only one or two layers of solvating water from the membrane surface and (b) steric interactions. The detailed structure of the solvating water is responsible for the difference in the hydration force acting between DLPE membranes compared to DPPC membranes

  20. Practical training in the operation of nuclear power plants with Interactive Graphic Simulator of Zorita

    International Nuclear Information System (INIS)

    Cuervo, D.; Garcia-Herranz, N.; Garcia, S.; Davila, R.; Ahnert, C.; Aragones, J. M.; Cabellos, O.; Gallego, E.; Lorente, A.; Minguez, E.; Rebollo, L.; Blanco, J.

    2010-01-01

    In April 2008 a collaboration agreement was signed between Gas Natural Union Fenosa and the Universad Politecnica de Madrid for the creation of the Aula Jose Cabrera dedicated to train professionals in the field of nuclear technology. The Classroom located in the Department of Nuclear Engineering, has been equipped with the Interactive Graphic Simulator of Zorita (SGIZ). The use of the simulator intended to improve the quality of teaching in the area of Nuclear Engineering. It integrates in the teachings of Industrial Engineering degree and the Master of Nuclear Science and Technology. Different manuals are under preparation to make it a suitable tool for teaching purpose. These manuals will guide the student so that learning takes place both through the guidance of the teacher as independently. (Author) 3 refs.

  1. Fluid-structure interaction computations for geometrically resolved rotor simulations using CFD

    DEFF Research Database (Denmark)

    Heinz, Joachim Christian; Sørensen, Niels N.; Zahle, Frederik

    2016-01-01

    fluid dynamics (CFD) solver EllipSys3D. The paper shows that the implemented loose coupling scheme, despite a non-conservative force transfer, maintains a sufficient numerical stability and a second-order time accuracy. The use of a strong coupling is found to be redundant. In a first test case......This paper presents a newly developed high-fidelity fluid–structure interaction simulation tool for geometrically resolved rotor simulations of wind turbines. The tool consists of a partitioned coupling between the structural part of the aero-elastic solver HAWC2 and the finite volume computational......, the newly developed coupling between HAWC2 and EllipSys3D (HAWC2CFD) is utilized to compute the aero-elastic response of the NREL 5-MW reference wind turbine (RWT) under normal operational conditions. A comparison with the low-fidelity but state-of-the-art aero-elastic solver HAWC2 reveals a very good...

  2. Multi-scale interactions of geological processes during mineralization: cascade dynamics model and multifractal simulation

    Directory of Open Access Journals (Sweden)

    L. Yao

    2011-03-01

    Full Text Available Relations between mineralization and certain geological processes are established mostly by geologist's knowledge of field observations. However, these relations are descriptive and a quantitative model of how certain geological processes strengthen or hinder mineralization is not clear, that is to say, the mechanism of the interactions between mineralization and the geological framework has not been thoroughly studied. The dynamics behind these interactions are key in the understanding of fractal or multifractal formations caused by mineralization, among which singularities arise due to anomalous concentration of metals in narrow space. From a statistical point of view, we think that cascade dynamics play an important role in mineralization and studying them can reveal the nature of the various interactions throughout the process. We have constructed a multiplicative cascade model to simulate these dynamics. The probabilities of mineral deposit occurrences are used to represent direct results of mineralization. Multifractal simulation of probabilities of mineral potential based on our model is exemplified by a case study dealing with hydrothermal gold deposits in southern Nova Scotia, Canada. The extent of the impacts of certain geological processes on gold mineralization is related to the scale of the cascade process, especially to the maximum cascade division number nmax. Our research helps to understand how the singularity occurs during mineralization, which remains unanswered up to now, and the simulation may provide a more accurate distribution of mineral deposit occurrences that can be used to improve the results of the weights of evidence model in mapping mineral potential.

  3. Rescaled Local Interaction Simulation Approach for Shear Wave Propagation Modelling in Magnetic Resonance Elastography

    Directory of Open Access Journals (Sweden)

    Z. Hashemiyan

    2016-01-01

    Full Text Available Properties of soft biological tissues are increasingly used in medical diagnosis to detect various abnormalities, for example, in liver fibrosis or breast tumors. It is well known that mechanical stiffness of human organs can be obtained from organ responses to shear stress waves through Magnetic Resonance Elastography. The Local Interaction Simulation Approach is proposed for effective modelling of shear wave propagation in soft tissues. The results are validated using experimental data from Magnetic Resonance Elastography. These results show the potential of the method for shear wave propagation modelling in soft tissues. The major advantage of the proposed approach is a significant reduction of computational effort.

  4. Atomistic simulations of anionic Au-144(SR)(60) nanoparticles interacting with asymmetric model lipid membranes

    DEFF Research Database (Denmark)

    Heikkila, E.; Martinez-Seara, H.; Gurtovenko, A. A.

    2014-01-01

    whose lipid composition and transmembrane distribution are to a large extent consistent with real plasma membranes of eukaryotic cells. To this end, we use a model system which comprises two cellular compartments, extracellular and cytosolic, divided by two asymmetric lipid bilayers. The simulations...... clearly show that AuNP- attaches to the extracellular membrane surface within a few tens of nanoseconds, while it avoids contact with the membrane on the cytosolic side. This behavior stems from several factors. In essence, when the nanoparticle interacts with lipids in the extracellular compartment...

  5. Experimental phantom verification studies for simulations of light interactions with skin: liquid phantoms

    CSIR Research Space (South Africa)

    Karsten, A

    2010-09-01

    Full Text Available stream_source_info Karsten_2010_P.pdf.txt stream_content_type text/plain stream_size 5080 Content-Encoding UTF-8 stream_name Karsten_2010_P.pdf.txt Content-Type text/plain; charset=UTF-8 Experimental phantom verification... studies for simulations of light interactions with skin: Solid Phantoms Aletta E Karsten, A Singh Presented by: J E Smit National Laser Center CSIR South Africa akarsten@csir.co.za Slide 2 © CSIR 2009 www.csir.co.za Where...

  6. Caffeine and Sugars Interact in Aqueous Solutions: A Simulation and NMR Study

    OpenAIRE

    Tavagnacco, Letizia; Engström, Olof; Schnupf, Udo; Saboungi, Marie-Louise; Himmel, Michael; Widmalm, Göran; Cesàro, Attilio; Brady, John W.

    2012-01-01

    Molecular dynamics simulations were carried out on several systems of caffeine interacting with simple sugars. These included a single caffeine molecule in a 3 molal solution of α-D-glucopyranose, at a caffeine concentration of 0.083 molal; a single caffeine in a 3 molal solution of β-D-glucopyranose, and a single caffeine molecule in a 1.08 molal solution of sucrose (table sugar). Parallel Nuclear Magnetic Resonance titration experiments were carried out on the same solutions under similar c...

  7. Breaking up of pure and simulated 'burnt' mixed oxide fuel by chemical interaction with oxidized sodium

    International Nuclear Information System (INIS)

    Besnard, R.; Chaudat, J.P.

    1983-01-01

    A large experimental program have permitted to investigate the behaviour of mixed oxide fuel coming in contact with hot oxidized sodium. The kinetic of the reaction, the size and the chemical nature of the particules after interaction have been studied. The main part of experiments have been performed using mixed oxide fuel non irradiated at first and with simulated fission products afterwards. Complementary informations have been obtained with UO 2 fuel pellets. After description of the experimental devices, the results are discussed and the importance of the main parameters, like temperature and fission products effect, are pointed out. (orig.)

  8. Volkov basis for simulation of interaction of strong laser pulses and solids

    Science.gov (United States)

    Kidd, Daniel; Covington, Cody; Li, Yonghui; Varga, Kálmán

    2018-01-01

    An efficient and accurate basis comprised of Volkov states is implemented and tested for time-dependent simulations of interactions between strong laser pulses and crystalline solids. The Volkov states are eigenstates of the free electron Hamiltonian in an electromagnetic field and analytically represent the rapidly oscillating time-dependence of the orbitals, allowing significantly faster time propagation than conventional approaches. The Volkov approach can be readily implemented in plane-wave codes by multiplying the potential energy matrix elements with a simple time-dependent phase factor.

  9. EPRI compact analyzer: A compact, interactive and color-graphics based simulator for power plant analysis

    International Nuclear Information System (INIS)

    Ipakchi, A.; Khadem, M.; Chen, H.; Colley, R.W.

    1986-01-01

    This paper presents the results of an EPRI sponsored project (RP2395-2) for design and development of an interactive, and color graphics based simulator for power plant analysis. The system is called Compact Analyzer and can be applied to engineering and training applications in the utility industry. The Compact Analyzer's software and system design are described. Results of two demonstration system for a nuclear plant, and a fossil plant are presented, and the applications of the Compact Analyzer to operating procedures evaluation are discussed

  10. Rescaled Local Interaction Simulation Approach for Shear Wave Propagation Modelling in Magnetic Resonance Elastography

    Science.gov (United States)

    Packo, P.; Staszewski, W. J.; Uhl, T.

    2016-01-01

    Properties of soft biological tissues are increasingly used in medical diagnosis to detect various abnormalities, for example, in liver fibrosis or breast tumors. It is well known that mechanical stiffness of human organs can be obtained from organ responses to shear stress waves through Magnetic Resonance Elastography. The Local Interaction Simulation Approach is proposed for effective modelling of shear wave propagation in soft tissues. The results are validated using experimental data from Magnetic Resonance Elastography. These results show the potential of the method for shear wave propagation modelling in soft tissues. The major advantage of the proposed approach is a significant reduction of computational effort. PMID:26884808

  11. Influence of Concrete Properties on Molten Core-Concrete Interaction: A Simulation Study

    Directory of Open Access Journals (Sweden)

    Jin-yang Jiang

    2016-01-01

    Full Text Available In a severe nuclear power plant accident, the molten core can be released into the reactor pit and interact with sacrificial concrete. In this paper, a simulation study is presented that aims to address the influence of sacrificial concrete properties on molten core-concrete interaction (MCCI. In particular, based on the MELCOR Code, the ferrosiliceous concrete used in European Pressurized Water Reactor (EPR is taken into account with respect to the different ablation enthalpy and Fe2O3 and H2O contents. Results indicate that the concrete ablation rate as well as the hydrogen generation rate depends much on the concrete ablation enthalpy and Fe2O3 and H2O contents. In practice, the ablation enthalpy of sacrificial concrete is the higher the better, while the Fe2O3 and H2O content of sacrificial concrete is the lower the better.

  12. Effects of septum and pericardium on heart-lung interactions in a cardiopulmonary simulation model.

    Science.gov (United States)

    Karamolegkos, Nikolaos; Albanese, Antonio; Chbat, Nicolas W

    2017-07-01

    Mechanical heart-lung interactions are often overlooked in clinical settings. However, their impact on cardiac function can be quite significant. Mechanistic physiology-based models can provide invaluable insights into such cardiorespiratory interactions, which occur not only under external mechanical ventilatory support but in normal physiology as well. In this work, we focus on the cardiac component of a previously developed mathematical model of the human cardiopulmonary system, aiming to improve the model's response to the intrathoracic pressure variations that are associated with the respiratory cycle. Interventricular septum and pericardial membrane are integrated into the existing model. Their effect on the overall cardiac response is explained by means of comparison against simulation results from the original model as well as experimental data from literature.

  13. Precise calculations in simulations of the interaction of low energy neutrons with nano-dispersed media

    International Nuclear Information System (INIS)

    Artem’ev, V. A.; Nezvanov, A. Yu.; Nesvizhevsky, V. V.

    2016-01-01

    We discuss properties of the interaction of slow neutrons with nano-dispersed media and their application for neutron reflectors. In order to increase the accuracy of model simulation of the interaction of neutrons with nanopowders, we perform precise quantum mechanical calculation of potential scattering of neutrons on single nanoparticles using the method of phase functions. We compare results of precise calculations with those performed within first Born approximation for nanodiamonds with the radius of 2–5 nm and for neutron energies 3 × 10 -7 –10 -3 eV. Born approximation overestimates the probability of scattering to large angles, while the accuracy of evaluation of integral characteristics (cross sections, albedo) is acceptable. Using Monte-Carlo method, we calculate albedo of neutrons from different layers of piled up diamond nanopowder

  14. Precise calculations in simulations of the interaction of low energy neutrons with nano-dispersed media

    Science.gov (United States)

    Artem'ev, V. A.; Nezvanov, A. Yu.; Nesvizhevsky, V. V.

    2016-01-01

    We discuss properties of the interaction of slow neutrons with nano-dispersed media and their application for neutron reflectors. In order to increase the accuracy of model simulation of the interaction of neutrons with nanopowders, we perform precise quantum mechanical calculation of potential scattering of neutrons on single nanoparticles using the method of phase functions. We compare results of precise calculations with those performed within first Born approximation for nanodiamonds with the radius of 2-5 nm and for neutron energies 3 × 10-7-10-3 eV. Born approximation overestimates the probability of scattering to large angles, while the accuracy of evaluation of integral characteristics (cross sections, albedo) is acceptable. Using Monte-Carlo method, we calculate albedo of neutrons from different layers of piled up diamond nanopowder.

  15. Interaction of lysozyme with a tear film lipid layer model: A molecular dynamics simulation study.

    Science.gov (United States)

    Wizert, Alicja; Iskander, D Robert; Cwiklik, Lukasz

    2017-12-01

    The tear film is a thin multilayered structure covering the cornea. Its outermost layer is a lipid film underneath of which resides on an aqueous layer. This tear film lipid layer (TFLL) is itself a complex structure, formed by both polar and nonpolar lipids. It was recently suggested that due to tear film dynamics, TFLL contains inhomogeneities in the form of polar lipid aggregates. The aqueous phase of tear film contains lachrymal-origin proteins, whereby lysozyme is the most abundant. These proteins can alter TFLL properties, mainly by reducing its surface tension. However, a detailed nature of protein-lipid interactions in tear film is not known. We investigate the interactions of lysozyme with TFLL in molecular details by employing coarse-grained molecular dynamics simulations. We demonstrate that lysozyme, due to lateral restructuring of TFLL, is able to penetrate the tear lipid film embedded in inverse micellar aggregates. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Equilibrium magnetization and microstructure of the system of superparamagnetic interacting particles: numerical simulation

    CERN Document Server

    Pshenichnikov, A F

    2000-01-01

    The Monte Carlo method is used to study the equilibrium magnetization of a 3D system of superparamagnetic particles taking into account the steric and dipole-dipole interparticle interactions. Two types of systems are considered: magnetic fluids and solidified ferrocolloids containing randomly spatially distributed particles with negligible energy of magnetic anisotropy. The results of numerical simulations confirm the universality of Langevin susceptibility as a main dimensionless parameter determining the influence of interparticle interactions on the magnetization of the system for moderate values of the aggregation parameter. The obtained results are in good agreement with theoretical and experimental data. At large values of the aggregation parameter, the clustering of particles in magnetic fluids is observed resulting in a reduction of their magnetization as compared to solidified systems. It is shown that the magnetization of solidified systems can be well described by the modified effective field appr...

  17. Equilibrium magnetization and microstructure of the system of superparamagnetic interacting particles: numerical simulation

    International Nuclear Information System (INIS)

    Pshenichnikov, A.F.; Mekhonoshin, V.V.

    2000-01-01

    The Monte Carlo method is used to study the equilibrium magnetization of a 3D system of superparamagnetic particles taking into account the steric and dipole-dipole interparticle interactions. Two types of systems are considered: magnetic fluids and solidified ferrocolloids containing randomly spatially distributed particles with negligible energy of magnetic anisotropy. The results of numerical simulations confirm the universality of Langevin susceptibility as a main dimensionless parameter determining the influence of interparticle interactions on the magnetization of the system for moderate values of the aggregation parameter. The obtained results are in good agreement with theoretical and experimental data. At large values of the aggregation parameter, the clustering of particles in magnetic fluids is observed resulting in a reduction of their magnetization as compared to solidified systems. It is shown that the magnetization of solidified systems can be well described by the modified effective field approximation within the whole investigated range of parameters

  18. Simulation code for the interaction of 14 MeV neutrons on cells

    Energy Technology Data Exchange (ETDEWEB)

    Nenot, M.L.; Alard, J.P.; Dionet, C.; Arnold, J.; Tchirkov, A.; Meunier, H.; Bodez, V.; Rapp, M.; Verrelle, P

    2002-07-01

    The structure of the survival curve of melanoma cells irradiated by 14 MeV neutrons displays unusual features at very low dose rate where a marked increase in cell killings at 0.05 Gy is followed by a plateau for survival from 0.1 to 0.32 Gy. In parallel a simulation code was constructed for the interaction of 14 MeV neutrons with cellular cultures. The code describes the interaction of the neutrons with the atomic nuclei of the cellular medium and of the external medium (flask culture and culture medium), and is used to compute the deposited energy into the cell volume. It was found that the large energy transfer events associated with heavy charged recoil can occur and that a large part of the energy deposition events are due to recoil protons emitted from the external medium. It is suggested that such events could partially explain the experimental results. (author)

  19. Precise calculations in simulations of the interaction of low energy neutrons with nano-dispersed media

    Energy Technology Data Exchange (ETDEWEB)

    Artem’ev, V. A., E-mail: niitm@inbox.ru [Research Institute of Materials Technology (Russian Federation); Nezvanov, A. Yu. [Moscow State Industrial University (Russian Federation); Nesvizhevsky, V. V. [Institut Max von Laue—Paul Langevin (France)

    2016-01-15

    We discuss properties of the interaction of slow neutrons with nano-dispersed media and their application for neutron reflectors. In order to increase the accuracy of model simulation of the interaction of neutrons with nanopowders, we perform precise quantum mechanical calculation of potential scattering of neutrons on single nanoparticles using the method of phase functions. We compare results of precise calculations with those performed within first Born approximation for nanodiamonds with the radius of 2–5 nm and for neutron energies 3 × 10{sup -7}–10{sup -3} eV. Born approximation overestimates the probability of scattering to large angles, while the accuracy of evaluation of integral characteristics (cross sections, albedo) is acceptable. Using Monte-Carlo method, we calculate albedo of neutrons from different layers of piled up diamond nanopowder.

  20. Capturing the spectrum of interaction effects in genetic association studies by simulated evaporative cooling network analysis.

    Directory of Open Access Journals (Sweden)

    Brett A McKinney

    2009-03-01

    Full Text Available Evidence from human genetic studies of several disorders suggests that interactions between alleles at multiple genes play an important role in influencing phenotypic expression. Analytical methods for identifying Mendelian disease genes are not appropriate when applied to common multigenic diseases, because such methods investigate association with the phenotype only one genetic locus at a time. New strategies are needed that can capture the spectrum of genetic effects, from Mendelian to multifactorial epistasis. Random Forests (RF and Relief-F are two powerful machine-learning methods that have been studied as filters for genetic case-control data due to their ability to account for the context of alleles at multiple genes when scoring the relevance of individual genetic variants to the phenotype. However, when variants interact strongly, the independence assumption of RF in the tree node-splitting criterion leads to diminished importance scores for relevant variants. Relief-F, on the other hand, was designed to detect strong interactions but is sensitive to large backgrounds of variants that are irrelevant to classification of the phenotype, which is an acute problem in genome-wide association studies. To overcome the weaknesses of these data mining approaches, we develop Evaporative Cooling (EC feature selection, a flexible machine learning method that can integrate multiple importance scores while removing irrelevant genetic variants. To characterize detailed interactions, we construct a genetic-association interaction network (GAIN, whose edges quantify the synergy between variants with respect to the phenotype. We use simulation analysis to show that EC is able to identify a wide range of interaction effects in genetic association data. We apply the EC filter to a smallpox vaccine cohort study of single nucleotide polymorphisms (SNPs and infer a GAIN for a collection of SNPs associated with adverse events. Our results suggest an important

  1. Lipid bilayers driven to a wrong lane in molecular dynamics simulations by subtle changes in long-range electrostatic interactions

    NARCIS (Netherlands)

    Patra, M.; Karttunen, M.E.J.; Hyvönen, M.T.; Falck, E.; Vattulainen, I.

    2004-01-01

    We provide compelling evidence that different treatments of electrostatic interactions in molecular dynamics simulations may dramatically affect dynamic properties of lipid bilayers. To this end, we consider a fully hydrated pure dipalmitoylphosphatidylcholine bilayer through 50-ns molecular

  2. Molecular dynamics simulations revealed structural differences among WRKY domain-DNA interaction in barley (Hordeum vulgare).

    Science.gov (United States)

    Pandey, Bharati; Grover, Abhinav; Sharma, Pradeep

    2018-02-12

    The WRKY transcription factors are a class of DNA-binding proteins involved in diverse plant processes play critical roles in response to abiotic and biotic stresses. Genome-wide divergence analysis of WRKY gene family in Hordeum vulgare provided a framework for molecular evolution and functional roles. So far, the crystal structure of WRKY from barley has not been resolved; moreover, knowledge of the three-dimensional structure of WRKY domain is pre-requisites for exploring the protein-DNA recognition mechanisms. Homology modelling based approach was used to generate structures for WRKY DNA binding domain (DBD) and its variants using AtWRKY1 as a template. Finally, the stability and conformational changes of the generated model in unbound and bound form was examined through atomistic molecular dynamics (MD) simulations for 100 ns time period. In this study, we investigated the comparative binding pattern of WRKY domain and its variants with W-box cis-regulatory element using molecular docking and dynamics (MD) simulations assays. The atomic insight into WRKY domain exhibited significant variation in the intermolecular hydrogen bonding pattern, leading to the structural anomalies in the variant type and differences in the DNA-binding specificities. Based on the MD analysis, residual contribution and interaction contour, wild-type WRKY (HvWRKY46) were found to interact with DNA through highly conserved heptapeptide in the pre- and post-MD simulated complexes, whereas heptapeptide interaction with DNA was missing in variants (I and II) in post-MD complexes. Consequently, through principal component analysis, wild-type WRKY was also found to be more stable by obscuring a reduced conformational space than the variant I (HvWRKY34). Lastly, high binding free energy for wild-type and variant II allowed us to conclude that wild-type WRKY-DNA complex was more stable relative to variants I. The results of our study revealed complete dynamic and structural information

  3. Decontamination and winter conditions

    International Nuclear Information System (INIS)

    Quenild, C.; Tveten, U.

    1984-12-01

    The report deals with two decontamonation experiments under winter conditions. A snow-covered parking lot was contaminated, and the snow was subsequently removed using standard snow-moving equipment. The snow left behind was collected and the content of contaminant was determined. A non-radioactive contaminant was used. A decontamination factor exceeding 100 was obtained. Although the eksperimental conditions were close to ideal, it is reason to believe that extremely efficient removal of deposited materials on a snow surface is achivable. In another investigation, run-off from agricultural surface, contaminated while covered with snow, was measured A lycimeter was used in this experiment. A stable layer of ice and snow was allowed to form before contamination. The run-off water was collected at each thaw period until all snow and ice was gone. Cs-134 was used as contaminant. Roughly 30% of the Cs-134 with which the area was contaminated ran off with the melt water. Following a reactor accident situation, this would have given a corresponding reduction in the long term doses. Both of these experiments show that consequence calculation assumptions, as they are currently applied to large accident assessment, tend to overestimate the consequences resulting from accidents taking place under winter conditions

  4. Spirit's Winter Work Site

    Science.gov (United States)

    2006-01-01

    [figure removed for brevity, see original site] Annotated Version This portion of an image acquired by the Mars Reconnaissance Orbiter's High Resolution Imaging Science Experiment camera shows the Spirit rover's winter campaign site. Spirit was parked on a slope tilted 11 degrees to the north to maximize sunlight during the southern winter season. 'Tyrone' is an area where the rover's wheels disturbed light-toned soils. Remote sensing and in-situ analyses found the light-toned soil at Tyrone to be sulfate rich and hydrated. The original picture is catalogued as PSP_001513_1655_red and was taken on Sept. 29, 2006. NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Mars Reconnaissance Orbiter for NASA's Science Mission Directorate, Washington. Lockheed Martin Space Systems, Denver, is the prime contractor for the project and built the spacecraft. The High Resolution Imaging Science Experiment is operated by the University of Arizona, Tucson, and the instrument was built by Ball Aerospace and Technology Corp., Boulder, Colo.

  5. Winter School Les Houches

    CERN Document Server

    Lannoo, Michel; Bastard, Gérald; Voos, Michel; Boccara, Nino

    1986-01-01

    The Winter School held in Les Houches on March 12-21, 1985 was devoted to Semiconductor Heterojunctions and Superlattices, a topic which is recognized as being now one of the most interesting and active fields in semiconductor physics. In fact, following the pioneering work of Esaki and Tsu in 1970, the study of these two-dimensional semiconductor heterostructures has developed rapidly, both from the point of view of basic physics and of applications. For instance, modulation-doped heterojunctions are nowadays currently used to investigate the quantum Hall effect and to make very fast transistors. This book contains the lectures presented at this Winter School, showing in particular that many aspects of semiconductor heterojunctions and super­ lattices were treated, extending from the fabrication of these two-dimensional systems to their basic properties and applications in micro-and opto-electron­ ics. Among the subjects which were covered, one can quote as examples: molecular beam epitaxy and metallorgani...

  6. Simulation study on exchange interaction and unique magnetization near ferromagnetic morphotropic phase boundary.

    Science.gov (United States)

    Wei, Songrui; Liao, Xiaoqi; Gao, Yipeng; Yang, Sen; Wang, Dong; Song, Xiaoping

    2017-11-08

    Extensive efforts have been made in searching enhanced functionalities near the so-called morphotropic phase boundaries (MPBs) in both ferroelectric and ferromagnetic materials. Due to the exchange anti-symmetry of the wave function of fermions, it is widely recognized that the exchange interaction plays a critical role in ferromagnetism. As a quantum effect, the exchange interaction is magnitudes larger than electric interaction, leading to a fundamental difference between ferroelectricity and ferromagnetism. In this paper, we establish an energetic model capturing the interplay among the anisotropy energy, magnetostatic energy and the exchange energy to investigate systematically the effects of the exchange energy on the behavior of the ferromagnetic MPB. For the first time, it is found that the exchange energy can narrow the width of MPB region in the composition temperature phase diagram for ferromagnetic MPB systems. As temperature increases, MPB region becomes wider because of the weakening of the exchange interaction. Our simulation results suggest that the exchange energy play a critical role on the unique behavior of ferromagnetic MPB, which is in contrast different from that of ferroelectric MPB.

  7. Simulations of collisions between N-body classical systems in interaction

    International Nuclear Information System (INIS)

    Morisseau, Francois

    2006-05-01

    The Classical N-body Dynamics (CNBD) is dedicated to the simulation of collisions between classical systems. The 2-body interaction used here has the properties of the Van der Waals potential and depends on just a few parameters. This work has two main goals. First, some theoretical approaches assume that the dynamical stage of the collisions plays an important role. Moreover, colliding nuclei are supposed to present a 1. order liquid-gas phase transition. Several signals have been introduced to show this transition. We have searched for two of them: the bimodality of the mass asymmetry and negative heat capacity. We have found them and we give an explanation of their presence in our calculations. Second, we have improved the interaction by adding a Coulomb like potential and by taking into account the stronger proton-neutron interaction in nuclei. Then we have figured out the relations that exist between the parameters of the 2-body interaction and the properties of the systems. These studies allow us to fit the properties of the classical systems to those of the nuclei. In this manuscript the first results of this fit are shown. (author)

  8. Radiation interaction with substance and simulation of the nuclear geophysical problems

    International Nuclear Information System (INIS)

    Pshenichnyj, G.A.

    1982-01-01

    Main processes of interaction of various types of nuclear radiation (NR) with substance, NR transport theory and physical- mathematical simulation of basic problems of nuclear geophysics (NG) are considered. General classification of NG methods according to the type of the detected radiation with a more detailed division according to the physical essence of the interaction process employed is given. Direct NG problems are related to the study of space- energy radiation distribution in substance under certain cross sections of elementary interaction processes, substance properties and specified geometric conditions. The theoretical solution of the direct problems is based on using mathematical models of radiation transport in specified media. The NG inverse problems consist in determining element composition and other medium properties by data of integral or spectral characteristics of NR fields measurements. The NR in the course of its transport in substance can experience dozens of elementary interaction processes, the predominance of this or that process depending on NR energy, medium properties and geometric measurement conditions. This explains a wide NG method diversity. The Monte Carlo method application in the NR transport theory and various methods of decreasing calculations labour input are considered [ru

  9. Simulation of thermal phenomena expected in fuel coolant interactions in LMFBRs

    International Nuclear Information System (INIS)

    Yasin, J.

    1976-12-01

    High pressures and mechanical work may result when thermal energy is transferred from molten fuel to the coolant in a Liquid Metal Fast Breeder Reactor core meltdown accident. Two aspects of the interaction are examined in the thesis. First, the formation of high pressure pulses termed ''Vapor Explosions,'' and second, the distribution of the molten material into smaller particles, termed ''Fragmentation'', are studied. To understand the nature of the interaction simulant materials were used. Molten bismuth, molten tin and molten glass were dropped into water under various conditions. The interactions were recorded using multiflash and high speed photographing techniques. The pressure pulses were measured using transducers and the debris was examined by photographing them with an electron microscope. It was observed that vapor explosions have thresholds which depend on the material being dropped, its temperature and the bath conditions. The vapor explosions were enhanced by stratifying the bath. It was also noticed that the intensity of the vapor explosion depends on the way the molten drop fragmented in the initial stages of the interaction. The experiments with glass showed that the mode of fragmentation is important in determining when and if a vapor explosion is to be expected. The glass fragmented extensively but without any accompanying vapor explosion. The electron microscope photographs of the glass debris showed that thermal stress and surface tension phenomenon are apparently the cause of the fragmentation

  10. Molecular dynamics simulations of interactions between energetic dust and plasma-facing materials

    International Nuclear Information System (INIS)

    Niu, Guo-jian; Li, Xiao-chun; Xu, Qian; Yang, Zhong-shi; Luo, Guang-nan

    2015-01-01

    The interactions between dust and plasma-facing material (PFM) relate to the lifetime of PFM and impurity production. Series results have been obtained theoretically and experimentally but more detailed studies are needed. In present research, we investigate the evolution of kinetic, potential and total energy of plasma-facing material (PFM) in order to understand the dust/PFM interaction process. Three typical impacting energy are selected, i.e., 1, 10 and 100 keV/dust for low-, high- and hyper-energy impacting cases. For low impacting energy, dust particles stick on PFM surface without damaging it. Two typical time points exist and the temperature of PFM grows all the time but PFM structure experience a modifying process. Under high energy case, three typical points appear. The temperature curve fluctuates in the whole interaction process which indicates there are dust/PFM and kinetic/potential energy exchanges. In the hyper-energy case in present simulation, the violence dust/PFM interactions cause sputtering and crater investigating on energy evolution curves. We further propose the statistics of energy distribution. Results show that about half of impacting energy consumes on heating plasma-facing material meanwhile the other half on PFM structure deformation. Only a small proportion becomes kinetic energy of interstitial or sputtering atoms.

  11. Molecular dynamics simulations of interactions between energetic dust and plasma-facing materials

    Energy Technology Data Exchange (ETDEWEB)

    Niu, Guo-jian, E-mail: niugj@ipp.ac.cn [Institute of Plasma Physics Chinese Academy of Sciences, Hefei (China); Li, Xiao-chun; Xu, Qian; Yang, Zhong-shi [Hefei Center Physical Science and Technology, Hefei (China); Luo, Guang-nan [Institute of Plasma Physics Chinese Academy of Sciences, Hefei (China); Hefei Center Physical Science and Technology, Hefei (China); Hefei Science Center of CAS, Hefei (China)

    2015-11-15

    The interactions between dust and plasma-facing material (PFM) relate to the lifetime of PFM and impurity production. Series results have been obtained theoretically and experimentally but more detailed studies are needed. In present research, we investigate the evolution of kinetic, potential and total energy of plasma-facing material (PFM) in order to understand the dust/PFM interaction process. Three typical impacting energy are selected, i.e., 1, 10 and 100 keV/dust for low-, high- and hyper-energy impacting cases. For low impacting energy, dust particles stick on PFM surface without damaging it. Two typical time points exist and the temperature of PFM grows all the time but PFM structure experience a modifying process. Under high energy case, three typical points appear. The temperature curve fluctuates in the whole interaction process which indicates there are dust/PFM and kinetic/potential energy exchanges. In the hyper-energy case in present simulation, the violence dust/PFM interactions cause sputtering and crater investigating on energy evolution curves. We further propose the statistics of energy distribution. Results show that about half of impacting energy consumes on heating plasma-facing material meanwhile the other half on PFM structure deformation. Only a small proportion becomes kinetic energy of interstitial or sputtering atoms.

  12. Properties of Organic Liquids when Simulated with Long-Range Lennard-Jones Interactions.

    Science.gov (United States)

    Fischer, Nina M; van Maaren, Paul J; Ditz, Jonas C; Yildirim, Ahmet; van der Spoel, David

    2015-07-14

    In order to increase the accuracy of classical computer simulations, existing methodologies may need to be adapted. Hitherto, most force fields employ a truncated potential function to model van der Waals interactions, sometimes augmented with an analytical correction. Although such corrections are accurate for homogeneous systems with a long cutoff, they should not be used in inherently inhomogeneous systems such as biomolecular and interface systems. For such cases, a variant of the particle mesh Ewald algorithm (Lennard-Jones PME) was already proposed 20 years ago (Essmann et al. J. Chem. Phys. 1995, 103, 8577-8593), but it was implemented only recently (Wennberg et al. J. Chem. Theory Comput. 2013, 9, 3527-3537) in a major simulation code (GROMACS). The availability of this method allows surface tensions of liquids as well as bulk properties to be established, such as density and enthalpy of vaporization, without approximations due to truncation. Here, we report on simulations of ≈150 liquids (taken from a force field benchmark: Caleman et al. J. Chem. Theory Comput. 2012, 8, 61-74) using three different force fields and compare simulations with and without explicit long-range van der Waals interactions. We find that the density and enthalpy of vaporization increase for most liquids using the generalized Amber force field (GAFF, Wang et al. J. Comput. Chem. 2004, 25, 1157-1174) and the Charmm generalized force field (CGenFF, Vanommeslaeghe et al. J. Comput. Chem. 2010, 31, 671-690) but less so for OPLS/AA (Jorgensen and Tirado-Rives, Proc. Natl. Acad. Sci. U.S.A. 2005, 102, 6665-6670), which was parametrized with an analytical correction to the van der Waals potential. The surface tension increases by ≈10(-2) N/m for all force fields. These results suggest that van der Waals attractions in force fields are too strong, in particular for the GAFF and CGenFF. In addition to the simulation results, we introduce a new version of a web server, http

  13. Integrating international relations and environmental science course concepts through an interactive world politics simulation

    Science.gov (United States)

    Straub, K. H.; Kesgin, B.

    2012-12-01

    During the fall 2012 semester, students in two introductory courses at Susquehanna University - EENV:101 Environmental Science and POLI:131 World Affairs - will participate together in an online international relations simulation called Statecraft (www.statecraftsim.com). In this strategy game, students are divided into teams representing independent countries, and choose their government type (democracy, constitutional monarchy, communist totalitarian, or military dictatorship) and two country attributes (industrial, green, militaristic, pacifist, or scientific), which determine a set of rules by which that country must abide. Countries interact over issues such as resource distribution, war, pollution, immigration, and global climate change, and must also keep domestic political unrest to a minimum in order to succeed in the game. This simulation has typically been run in political science courses, as the goal is to allow students to experience the balancing act necessary to maintain control of global and domestic issues in a dynamic, diverse world. This semester, environmental science students will be integrated into the simulation, both as environmental advisers to each country and as independent actors representing groups such as Greenpeace, ExxonMobil, and UNEP. The goal in integrating the two courses in the simulation is for the students in each course to gain both 1) content knowledge of certain fundamental material in the other course, and 2) a more thorough, applied understanding of the integrated nature of the two subjects. Students will gain an appreciation for the multiple tradeoffs that decision-makers must face in the real world (economy, resources, pollution, health, defense, etc.). Environmental science students will link these concepts to the traditional course material through a "systems thinking" approach to sustainability. Political science students will face the challenges of global climate change and gain an understanding of the nature of

  14. A Monte Carlo simulation for the field theory with quartic interaction

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Sergio Mittmann dos [Instituto Federal de Educacao, Ciencia e Tecnologia do Rio Grande do Sul (IFRS), Porto Alegre, RS (Brazil)

    2011-07-01

    Full text: In the work [1-S. M. Santos, B. E. J. Bodmann and A. T. Gomez, Um novo metodo computacional para a teoria de campos na rede: resultados preliminares, IV Escola do Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, 2002; and 2-S. M. Santos and B. E. J. Bodmann, Simulacao na rede de teorias de campos quanticos, XXVIII Congresso Nacional de Matematica Aplicada e Computacional (CNMAC), Sao Paulo, 2005], a computational method on the lattice was elaborated for the problem known as scalar field theory with quartic interaction (for instance, see: J. R. Klauder, Beyound conventional quantization, Cambridge: Cambridge University Press, 2000). This one introduced an algorithm, which allows the simulation of a given field theory and is independent of the lattice spacing, by redefining the fields and the parameters (the mass m and the coupling constant g). This kind of approach permits varying the dimension of the lattice without changing the computational complexity of the algorithm. A simulation was made using the Monte Carlo method, where the renormalized mass m{sub R}, the renormalized coupling constant g{sub R} and the two point correlation function were determined with success. In the present work, the genuine computational method is used for new simulations. Now, the Monte Carlo method is not used just for the simulation of the algorithm, like in [1, 2], but also for defining the adjust parameters (the mass and the coupling constant), introduced ad hoc in [1, 2]. This work presents the first simulations' outcomes, where best results that [1, 2] were determined, for the renormalized mass and the renormalized coupling constant. (author)

  15. Building interactive virtual environments for simulated training in medicine using VRML and Java/JavaScript.

    Science.gov (United States)

    Korocsec, D; Holobar, A; Divjak, M; Zazula, D

    2005-12-01

    Medicine is a difficult thing to learn. Experimenting with real patients should not be the only option; simulation deserves a special attention here. Virtual Reality Modelling Language (VRML) as a tool for building virtual objects and scenes has a good record of educational applications in medicine, especially for static and animated visualisations of body parts and organs. However, to create computer simulations resembling situations in real environments the required level of interactivity and dynamics is difficult to achieve. In the present paper we describe some approaches and techniques which we used to push the limits of the current VRML technology further toward dynamic 3D representation of virtual environments (VEs). Our demonstration is based on the implementation of a virtual baby model, whose vital signs can be controlled from an external Java application. The main contributions of this work are: (a) outline and evaluation of the three-level VRML/Java implementation of the dynamic virtual environment, (b) proposal for a modified VRML Timesensor node, which greatly improves the overall control of system performance, and (c) architecture of the prototype distributed virtual environment for training in neonatal resuscitation comprising the interactive virtual newborn, active bedside monitor for vital signs and full 3D representation of the surgery room.

  16. A virtual control room with an embedded, interactive nuclear reactor simulator

    International Nuclear Information System (INIS)

    Markidis, S.; Rizwan, U.

    2006-01-01

    The use of virtual nuclear control room can be an effective and powerful tool for training personnel working in the nuclear power plants. Operators could experience and simulate the functioning of the plant, even in critical situations, without being in a real power plant or running any risk. 3D models can be exported to Virtual Reality formats and then displayed in the Virtual Reality environment providing an immersive 3D experience. However, two major limitations of this approach are that 3D models exhibit static textures, and they are not fully interactive and therefore cannot be used effectively in training personnel. In this paper we first describe a possible solution for embedding the output of a computer application in a 3D virtual scene, coupling real-world applications and VR systems. The VR system reported here grabs the output of an application running on an X server; creates a texture with the output and then displays it on a screen or a wall in the virtual reality environment. We then propose a simple model for providing interaction between the user in the VR system and the running simulator. This approach is based on the use of internet-based application that can be commanded by a laptop or tablet-pc added to the virtual environment. (authors)

  17. Electromagnetic particle-in-cell simulations of the solar wind interaction with lunar magnetic anomalies.

    Science.gov (United States)

    Deca, J; Divin, A; Lapenta, G; Lembège, B; Markidis, S; Horányi, M

    2014-04-18

    We present the first three-dimensional fully kinetic and electromagnetic simulations of the solar wind interaction with lunar crustal magnetic anomalies (LMAs). Using the implicit particle-in-cell code iPic3D, we confirm that LMAs may indeed be strong enough to stand off the solar wind from directly impacting the lunar surface forming a mini-magnetosphere, as suggested by spacecraft observations and theory. In contrast to earlier magnetohydrodynamics and hybrid simulations, the fully kinetic nature of iPic3D allows us to investigate the space charge effects and in particular the electron dynamics dominating the near-surface lunar plasma environment. We describe for the first time the interaction of a dipole model centered just below the lunar surface under plasma conditions such that only the electron population is magnetized. The fully kinetic treatment identifies electromagnetic modes that alter the magnetic field at scales determined by the electron physics. Driven by strong pressure anisotropies, the mini-magnetosphere is unstable over time, leading to only temporal shielding of the surface underneath. Future human exploration as well as lunar science in general therefore hinges on a better understanding of LMAs.

  18. Simulation of the thermomechanical interaction between pellet and cladding and fission gas release

    International Nuclear Information System (INIS)

    Denis, Alicia C.; Soba, Alejandro

    2000-01-01

    This paper summarizes the present status of a computer code that simulates some of the main phenomena occurring in a fuel element of a nuclear power reactor throughout its life. Temperature distribution, thermal expansion, elastic and plastic strains, creep, mechanical interaction between pellet and cladding, fission gas release, swelling and densification are modeled. Thermal expansion gives origin to elastic or plastic strains, which adequately describe the bamboo effect. The code assumes an axial symmetric rod and hence, cylindrical finite elements are employed for the discretization. The fission gas inventory is calculated by means of a diffusion model, which assumes spherical grains and uses also a finite element scheme. Once the temperature distribution in the pellet and the cladding is obtained and in order to reduce the calculation time, the rod is divided into five cylindrical rings where the temperature is averaged. In each ring the gas diffusion problem is solved in one representative grain and the results are then extended to the whole ring. The pressure, increased by the released gas, interacts with the stress field. Densification and swelling due to solid and gaseous fission products are also considered. Experiments, particularly those of the FUMEX series, are simulated with this code. A good agreement is obtained for the fuel center line temperature, the inside rod pressure and the fractional gas release. (author)

  19. Molecular Dynamics Simulation to Investigate the Interaction of Asphaltene and Oxide in Aggregate

    Directory of Open Access Journals (Sweden)

    Rui Li

    2016-01-01

    Full Text Available The asphalt-aggregate interface interaction (AAI plays a significant role in the overall performances of asphalt mixture, which is caused due to the complicated physicochemical processes and is influenced by various factors, including the acid-base property of aggregates. In order to analyze the effects of the chemical constitution of aggregate on the AAI, the average structure C65H74N2S2 is selected to represent the asphaltene in asphalt and magnesium oxide (MgO, calcium oxide (CaO, aluminium sesquioxide (Al2O3, and silicon dioxide (SiO2 are selected to represent the major oxides in aggregate. The molecular models are established for asphaltene and the four oxides, respectively, and the molecular dynamics (MD simulation was conducted for the four kinds of asphaltene-oxide system at different temperatures. The interfacial energy in MD simulation is calculated to evaluate the AAI, and higher value means better interaction. The results show that interfacial energy between asphaltene and oxide reaches the maximum value at 25°C and 80°C and the minimum value at 40°C. In addition, the interfacial energy between asphaltene and MgO was found to be the greatest, followed by CaO, Al2O3, and SiO2, which demonstrates that the AAI between asphalt and alkaline aggregates is better than acidic aggregates.

  20. Interactions of oxytetracycline with a smectite clay: a spectroscopic study with molecular simulations.

    Science.gov (United States)

    Aristilde, Ludmilla; Marichal, Claire; Miéhé-Brendlé, Jocelyne; Lanson, Bruno; Charlet, Laurent

    2010-10-15

    Binding of antibiotics to clay minerals can decrease both their physical and biological availability in soils. To elucidate the binding mechanisms of tetracycline antibiotics on smectite clays as a function of pH, we probed the interactions of oxytetracycline (OTC) with Na-montmorillonite (MONT) using X-ray diffraction (XRD), infrared (IR), and solid-state nuclear magnetic resonance (NMR) spectroscopies, and Monte Carlo molecular simulations. The XRD patterns demonstrate the presence of OTC in the MONT interlayer space at acidic pH whereas complexation of OTC by external basal and edge sites seems to prevail at pH 8. At both pH, the (1)H-(13)C NMR profile indicates restricted mobility of the adsorbed OTC species; and, -CH(3) deformation and C-N stretching IR vibration bands confirm a binding mechanism involving the protonated dimethylamino group of OTC. Changes in the (23)Na NMR environments are consistent with cation-exchange and cation complexation reactions at the different sites of adsorption. Molecular simulations indicate that MONT interlayer spacing and structural charge localization dictate favorable binding conformations of the intercalated OTC, facilitating multiple interactions in agreement with the spectroscopic data. Our results present complementary insights into the mechanisms of adsorption of TETs on smectites important for their retention in natural and engineered soil environments.

  1. Optimization of linear and branched alkane interactions with water to simulate hydrophobic hydration

    Science.gov (United States)

    Ashbaugh, Henry S.; Liu, Lixin; Surampudi, Lalitanand N.

    2011-08-01

    Previous studies of simple gas hydration have demonstrated that the accuracy of molecular simulations at capturing the thermodynamic signatures of hydrophobic hydration is linked both to the fidelity of the water model at replicating the experimental liquid density at ambient pressure and an accounting of polarization interactions between the solute and water. We extend those studies to examine alkane hydration using the transferable potentials for phase equilibria united-atom model for linear and branched alkanes, developed to reproduce alkane phase behavior, and the TIP4P/2005 model for water, which provides one of the best descriptions of liquid water for the available fixed-point charge models. Alkane site/water oxygen Lennard-Jones cross interactions were optimized to reproduce the experimental alkane hydration free energies over a range of temperatures. The optimized model reproduces the hydration free energies of the fitted alkanes with a root mean square difference between simulation and experiment of 0.06 kcal/mol over a wide temperature range, compared to 0.44 kcal/mol for the parent model. The optimized model accurately reproduces the temperature dependence of hydrophobic hydration, as characterized by the hydration enthalpies, entropies, and heat capacities, as well as the pressure response, as characterized by partial molar volumes.

  2. Wildfire Emissions and Their Interaction with Urban and Rural Pollution: Data and Simulations

    Science.gov (United States)

    Singh, H. B.

    2014-01-01

    In recent years NASA has conducted a series of airborne campaigns (e. g. SEAC4RS*, ARCTAS, INTEX-A/B) over North America using an instrumented DC-8 aircraft equipped to measure a very large number of gaseous and aerosol constituents including several unique tracers. In these campaigns wild fires were extensively sampled near source as well as downwind after aging. The data provided detailed information on the composition and chemistry of fire emissions under a variety of atmospheric conditions as well as their interactions with rural and urban air pollution. Major fires studied including the California Rim fire in 2013 (SEAC4RS), the 2008 California wildfires (ARCTAS), and the Alaskan fires downwind over eastern US (INTEX-A). Although some fire plumes contained virtually no O3 enhancement, others showed significant ozone formation. Over Los Angeles, the highest O3 mixing ratios were observed in fire influenced urban air masses. Attempts to simulate these interactions using state of the art models were only minimally successful and indicated several shortcomings in simulating fire emission influences on urban smog formation. A variety of secondary oxidation products (e. g. O3, PAN, HCHO) were substantially underestimated. We will discuss the data collected in fire influenced air masses and their potential air quality implications.

  3. Multi-fidelity numerical simulations of shock/turbulent-boundary layer interaction with uncertainty quantification

    Science.gov (United States)

    Bermejo-Moreno, Ivan; Campo, Laura; Larsson, Johan; Emory, Mike; Bodart, Julien; Palacios, Francisco; Iaccarino, Gianluca; Eaton, John

    2013-11-01

    We study the interaction between an oblique shock wave and the turbulent boundary layers inside a nearly-square duct by combining wall-modeled LES, 2D and 3D RANS simulations, targeting the experiment of Campo, Helmer & Eaton, 2012 (nominal conditions: M = 2 . 05 , Reθ = 6 , 500). A primary objective is to quantify the effect of aleatory and epistemic uncertainties on the STBLI. Aleatory uncertainties considered include the inflow conditions (Mach number of the incoming air stream and thickness of the boundary layers) and perturbations of the duct geometry upstream of the interaction. The epistemic uncertainty under consideration focuses on the RANS turbulence model form by injecting perturbations in the Reynolds stress anisotropy in regions of the flow where the model assumptions (in particular, the Boussinesq eddy-viscosity hypothesis) may be invalid. These perturbations are then propagated through the flow solver into the solution. The uncertainty quantification (UQ) analysis is done through 2D and 3D RANS simulations, assessing the importance of the three-dimensional effects imposed by the nearly-square duct geometry. Wall-modeled LES are used to verify elements of the UQ methodology and to explore the flow features and physics of the STBLI for multiple shock strengths. Financial support from the United States Department of Energy under the PSAAP program is gratefully acknowledged.

  4. A coarse-grained model for the simulations of biomolecular interactions in cellular environments

    International Nuclear Information System (INIS)

    Xie, Zhong-Ru; Chen, Jiawen; Wu, Yinghao

    2014-01-01

    The interactions of bio-molecules constitute the key steps of cellular functions. However, in vivo binding properties differ significantly from their in vitro measurements due to the heterogeneity of cellular environments. Here we introduce a coarse-grained model based on rigid-body representation to study how factors such as cellular crowding and membrane confinement affect molecular binding. The macroscopic parameters such as the equilibrium constant and the kinetic rate constant are calibrated by adjusting the microscopic coefficients used in the numerical simulations. By changing these model parameters that are experimentally approachable, we are able to study the kinetic and thermodynamic properties of molecular binding, as well as the effects caused by specific cellular environments. We investigate the volumetric effects of crowded intracellular space on bio-molecular diffusion and diffusion-limited reactions. Furthermore, the binding constants of membrane proteins are currently difficult to measure. We provide quantitative estimations about how the binding of membrane proteins deviates from soluble proteins under different degrees of membrane confinements. The simulation results provide biological insights to the functions of membrane receptors on cell surfaces. Overall, our studies establish a connection between the details of molecular interactions and the heterogeneity of cellular environments

  5. Interactions from diffraction data: historical and comprehensive overview of simulation assisted methods

    International Nuclear Information System (INIS)

    Toth, Gergely

    2007-01-01

    A large part of statistical mechanics is concerned with the determination of condensed matter structure on the basis of known microscopic interactions. An increasing emphasis has been put on the opposite situation in the last decades as well, where structural data, e.g. pair-distance statistics, are known from diffraction experiments, and one looks for the corresponding interaction functions. The solution of this inverse problem was searched for within the integral equation theories of condensed matter in the early investigations, but before long computer simulation assisted methods were suggested. The interest in this field showed an increasing trend after some attempts appeared in the late 1980s. Several methods were published in the 1990s, and one-two methods appear annually nowadays. In this paper a comprehensive and historical overview is given on the solution of the inverse problem with simulation assisted methods. Emphasis is put on the theoretical grounds of the methods, on the choice of possible input structural functions, on the numerically local or global schemes of the potential modifications, on some advantages and limits of the different methods and on the scientific impact of the methods

  6. Simulations of bremsstrahlung emission in ultra-intense laser interactions with foil targets

    Science.gov (United States)

    Vyskočil, Jiří; Klimo, Ondřej; Weber, Stefan

    2018-05-01

    Bremsstrahlung emission from interactions of short ultra-intense laser pulses with solid foils is studied using particle-in-cell (PIC) simulations. A module for simulating bremsstrahlung has been implemented in the PIC loop to self-consistently account for the dynamics of the laser–plasma interaction, plasma expansion, and the emission of gamma ray photons. This module made it possible to study emission from thin targets, where refluxing of hot electrons plays an important role. It is shown that the angular distribution of the emitted photons exhibits a four-directional structure with the angle of emission decreasing with the increase of the width of the target. Additionally, a collimated forward flash consisting of high energy photons has been identified in thin targets. The conversion efficiency of the energy of the laser pulse to the energy of the gamma rays rises with both the driving pulse intensity, and the thickness of the target. The amount of gamma rays also increases with the atomic number of the target material, despite a lower absorption of the driving laser pulse. The angular spectrum of the emitted gamma rays is directly related to the increase of hot electron divergence during their refluxing and its measurement can be used in experiments to study this process.

  7. Developing a Tool Point Control Scheme for a Hydraulic Crane Using Interactive Real-time Dynamic Simulation

    DEFF Research Database (Denmark)

    Pedersen, Mikkel Melters; Hansen, Michael Rygaard; Ballebye, Morten

    2010-01-01

    This paper describes the implementation of an interactive real-time dynamic simulation model of a hydraulic crane. The user input to the model is given continuously via joystick and output is presented continuously in a 3D animation. Using this simulation model, a tool point control scheme...... is developed for the specific crane, considering the saturation phenomena of the system and practical implementation....

  8. The Impact of Computer Simulations as Interactive Demonstration Tools on the Performance of Grade 11 Learners in Electromagnetism

    Science.gov (United States)

    Kotoka, Jonas; Kriek, Jeanne

    2014-01-01

    The impact of computer simulations on the performance of 65 grade 11 learners in electromagnetism in a South African high school in the Mpumalanga province is investigated. Learners did not use the simulations individually, but teachers used them as an interactive demonstration tool. Basic concepts in electromagnetism are difficult to understand…

  9. gRINN: a tool for calculation of residue interaction energies and protein energy network analysis of molecular dynamics simulations.

    Science.gov (United States)

    Serçinoglu, Onur; Ozbek, Pemra

    2018-05-25

    Atomistic molecular dynamics (MD) simulations generate a wealth of information related to the dynamics of proteins. If properly analyzed, this information can lead to new insights regarding protein function and assist wet-lab experiments. Aiming to identify interactions between individual amino acid residues and the role played by each in the context of MD simulations, we present a stand-alone software called gRINN (get Residue Interaction eNergies and Networks). gRINN features graphical user interfaces (GUIs) and a command-line interface for generating and analyzing pairwise residue interaction energies and energy correlations from protein MD simulation trajectories. gRINN utilizes the features of NAMD or GROMACS MD simulation packages and automatizes the steps necessary to extract residue-residue interaction energies from user-supplied simulation trajectories, greatly simplifying the analysis for the end-user. A GUI, including an embedded molecular viewer, is provided for visualization of interaction energy time-series, distributions, an interaction energy matrix, interaction energy correlations and a residue correlation matrix. gRINN additionally offers construction and analysis of Protein Energy Networks, providing residue-based metrics such as degrees, betweenness-centralities, closeness centralities as well as shortest path analysis. gRINN is free and open to all users without login requirement at http://grinn.readthedocs.io.

  10. An interactive graphic simulator for garona nuclear power plant: development and applications

    International Nuclear Information System (INIS)

    Corcuera, P.; Garces, M.; Melara, J.; Gonzalez, J.; Lopez, J.V.

    1999-01-01

    As a result of a R and D project jointly undertaken by Nuclenor S.A. and the University of Cantabria, since the beginning of 1995 Santa Maria de Garona NPP holds its own plant transient and accident simulator for the training of its operators on Emergency Procedures Guides (EPG's). This paper describes the process followed in its development and the derived projects. This interactive graphic simulator is based on the MAAP computer code with an interface developed with DataViews software for X-Window terminals running under UNIX on a Hewlet Packard series 9000/712 workstation. The themarhydraulical code MAAP, with modifications to include all the controls and systems of the plant was chosen due to its capability to simulate primary system, containment and reactor building behavior during transients and accidents of any kind, including those beyond the design basis and also severe accidents. Besides, this code is currently being used for the PSA of the plant. The current configuration consists of several monitors that displays the systems and components situation and the safety parameters through the SPDS (Safety Parameter Display System) displays. With this design the simulator has fulfilled its initial main purpose of training operators on abnormal and emergency procedure guides, revealing as a very efficient and cost effective tool to accomplish this task. Furthermore it has been improved to visualize the real time plant data through the simulator displays. It is also possible to distribute the simulated data to any computer connected to the local area network (LAN). This feature has been applied successfully in the last emergency drills. Other benefits are derived from the fact that the same code is used for training and for the PSA. As an example of its flexibility, the simulator is now being used to validate the new SPDS displays designed to improve the man-machine interface and then it will serve to train the operators on them before their installation at the

  11. Effective interactions in lysozyme aqueous solutions: a small-angle neutron scattering and computer simulation study.

    Science.gov (United States)

    Abramo, M C; Caccamo, C; Costa, D; Pellicane, G; Ruberto, R; Wanderlingh, U

    2012-01-21

    We report protein-protein structure factors of aqueous lysozyme solutions at different pH and ionic strengths, as determined by small-angle neutron scattering experiments. The observed upturn of the structure factor at small wavevectors, as the pH increases, marks a crossover between two different regimes, one dominated by repulsive forces, and another one where attractive interactions become prominent, with the ensuing development of enhanced density fluctuations. In order to rationalize such experimental outcome from a microscopic viewpoint, we have carried out extensive simulations of different coarse-grained models. We have first studied a model in which macromolecules are described as soft spheres interacting through an attractive r(-6) potential, plus embedded pH-dependent discrete charges; we show that the uprise undergone by the structure factor is qualitatively predicted. We have then studied a Derjaguin-Landau-Verwey-Overbeek (DLVO) model, in which only central interactions are advocated; we demonstrate that this model leads to a protein-rich/protein-poor coexistence curve that agrees quite well with the experimental counterpart; experimental correlations are instead reproduced only at low pH and ionic strengths. We have finally investigated a third, "mixed" model in which the central attractive term of the DLVO potential is imported within the distributed-charge approach; it turns out that the different balance of interactions, with a much shorter-range attractive contribution, leads in this latter case to an improved agreement with the experimental crossover. We discuss the relationship between experimental correlations, phase coexistence, and features of effective interactions, as well as possible paths toward a quantitative prediction of structural properties of real lysozyme solutions. © 2012 American Institute of Physics

  12. Experimental simulation: using generative modelling and palaeoecological data to understand human-environment interactions

    Directory of Open Access Journals (Sweden)

    George Perry

    2016-10-01

    Full Text Available The amount of palaeoecological information available continues to grow rapidly, providing improved descriptions of the dynamics of past ecosystems and enabling them to be seen from new perspectives. At the same time, there has been concern over whether palaeoecological enquiry needs to move beyond descriptive inference to a more hypothesis-focussed or experimental approach; however, the extent to which conventional hypothesis-driven scientific frameworks can be applied to historical contexts (i.e., the past is the subject of ongoing debate. In other disciplines concerned with human-environment interactions, including physical geography and archaeology, there has been growing use of generative simulation models, typified by agent-based approaches. Generative modelling encourages counter-factual questioning (what if…?, a mode of argument that is particularly important in systems and time-periods, such as the Holocene and now the Anthropocene, where the effects of humans and other biophysical processes are deeply intertwined. However, palaeoecologically focused simulation of the dynamics of the ecosystems of the past either seems to be conducted to assess the applicability of some model to the future or treats humans simplistically as external forcing factors. In this review we consider how generative simulation-modelling approaches could contribute to our understanding of past human-environment interactions. We consider two key issues: the need for null models for understanding past dynamics and the need to be able learn more from pattern-based analysis. In this light, we argue that there is considerable scope for palaeocology to benefit from developments in generative models and their evaluation. We discuss the view that simulation is a form of experiment and, by using case studies, consider how the many patterns available to palaeoecologists can support model evaluation in a way that moves beyond simplistic pattern-matching and how such models

  13. Simulation technique for slurries interacting with moving parts and deformable solids with applications

    Science.gov (United States)

    Mutabaruka, Patrick; Kamrin, Ken

    2018-04-01

    A numerical method for particle-laden fluids interacting with a deformable solid domain and mobile rigid parts is proposed and implemented in a full engineering system. The fluid domain is modeled with a lattice Boltzmann representation, the particles and rigid parts are modeled with a discrete element representation, and the deformable solid domain is modeled using a Lagrangian mesh. The main issue of this work, since separately each of these methods is a mature tool, is to develop coupling and model-reduction approaches in order to efficiently simulate coupled problems of this nature, as in various geological and engineering applications. The lattice Boltzmann method incorporates a large eddy simulation technique using the Smagorinsky turbulence model. The discrete element method incorporates spherical and polyhedral particles for stiff contact interactions. A neo-Hookean hyperelastic model is used for the deformable solid. We provide a detailed description of how to couple the three solvers within a unified algorithm. The technique we propose for rubber modeling/coupling exploits a simplification that prevents having to solve a finite-element problem at each time step. We also developed a technique to reduce the domain size of the full system by replacing certain zones with quasi-analytic solutions, which act as effective boundary conditions for the lattice Boltzmann method. The major ingredients of the routine are separately validated. To demonstrate the coupled method in full, we simulate slurry flows in two kinds of piston valve geometries. The dynamics of the valve and slurry are studied and reported over a large range of input parameters.

  14. Convergence acceleration for partitioned simulations of the fluid-structure interaction in arteries

    Science.gov (United States)

    Radtke, Lars; Larena-Avellaneda, Axel; Debus, Eike Sebastian; Düster, Alexander

    2016-06-01

    We present a partitioned approach to fluid-structure interaction problems arising in analyses of blood flow in arteries. Several strategies to accelerate the convergence of the fixed-point iteration resulting from the coupling of the fluid and the structural sub-problem are investigated. The Aitken relaxation and variants of the interface quasi-Newton -least-squares method are applied to different test cases. A hybrid variant of two well-known variants of the interface quasi-Newton-least-squares method is found to perform best. The test cases cover the typical boundary value problem faced when simulating the fluid-structure interaction in arteries, including a strong added mass effect and a wet surface which accounts for a large part of the overall surface of each sub-problem. A rubber-like Neo Hookean material model and a soft-tissue-like Holzapfel-Gasser-Ogden material model are used to describe the artery wall and are compared in terms of stability and computational expenses. To avoid any kind of locking, high-order finite elements are used to discretize the structural sub-problem. The finite volume method is employed to discretize the fluid sub-problem. We investigate the influence of mass-proportional damping and the material model chosen for the artery on the performance and stability of the acceleration strategies as well as on the simulation results. To show the applicability of the partitioned approach to clinical relevant studies, the hemodynamics in a pathologically deformed artery are investigated, taking the findings of the test case simulations into account.

  15. Final Report: Model interacting particle systems for simulation and macroscopic description of particulate suspensions

    Energy Technology Data Exchange (ETDEWEB)

    Peter J. Mucha

    2007-08-30

    Suspensions of solid particles in liquids appear in numerous applications, from environmental settings like river silt, to industrial systems of solids transport and water treatment, and biological flows such as blood flow. Despite their importance, much remains unexplained about these complicated systems. Mucha's research aims to improve understanding of basic properties of suspensions through a program of simulating model interacting particle systems with critical evaluation of proposed continuum equations, in close collaboration with experimentalists. Natural to this approach, the original proposal centered around collaboration with studies already conducted in various experimental groups. However, as was detailed in the 2004 progress report, following the first year of this award, a number of the questions from the original proposal were necessarily redirected towards other specific goals because of changes in the research programs of the proposed experimental collaborators. Nevertheless, the modified project goals and the results that followed from those goals maintain close alignment with the main themes of the original proposal, improving efficient simulation and macroscopic modeling of sedimenting and colloidal suspensions. In particular, the main investigations covered under this award have included: (1) Sedimentation instabilities, including the sedimentation analogue of the Rayleigh-Taylor instability (for heavy, particle-laden fluid over lighter, clear fluid). (2) Ageing dynamics of colloidal suspensions at concentrations above the glass transition, using simplified interactions. (3) Stochastic reconstruction of velocity-field dependence for particle image velocimetry (PIV). (4) Stochastic modeling of the near-wall bias in 'nano-PIV'. (5) Distributed Lagrange multiplier simulation of the 'internal splash' of a particle falling through a stable stratified interface. (6) Fundamental study of velocity fluctuations in sedimentation

  16. Theory and simulation studies of effective interactions, phase behavior and morphology in polymer nanocomposites.

    Science.gov (United States)

    Ganesan, Venkat; Jayaraman, Arthi

    2014-01-07

    Polymer nanocomposites are a class of materials that consist of a polymer matrix filled with inorganic/organic nanoscale additives that enhance the inherent macroscopic (mechanical, optical and electronic) properties of the polymer matrix. Over the past few decades such materials have received tremendous attention from experimentalists, theoreticians, and computational scientists. These studies have revealed that the macroscopic properties of polymer nanocomposites depend strongly on the (microscopic) morphology of the constituent nanoscale additives in the polymer matrix. As a consequence, intense research efforts have been directed to understand the relationships between interactions, morphology, and the phase behavior of polymer nanocomposites. Theory and simulations have proven to be useful tools in this regard due to their ability to link molecular level features of the polymer and nanoparticle additives to the resulting morphology within the composite. In this article we review recent theory and simulation studies, presenting briefly the methodological developments underlying PRISM theories, density functional theory, self-consistent field theory approaches, and atomistic and coarse-grained molecular simulations. We first discuss the studies on polymer nanocomposites with bare or un-functionalized nanoparticles as additives, followed by a review of recent work on composites containing polymer grafted or functionalized nanoparticles as additives. We conclude each section with a brief outlook on some potential future directions.

  17. In-situ electrochemical study of interaction of tribology and corrosion in artificial hip prosthesis simulators.

    Science.gov (United States)

    Yan, Yu; Dowson, Duncan; Neville, Anne

    2013-02-01

    The second generation Metal-on-Metal (MoM) hip replacements have been considered as an alternative to commonly used Polyethylene-on-Metal (PoM) joint prostheses due to polyethylene wear debris induced osteolysis. However, the role of corrosion and the biofilm formed under tribological contact are still not fully understood. Enhanced metal ion concentrations have been reported widely from hair, blood and urine samples of patients who received metal hip replacements and in isolated cases when abnormally high levels have caused adverse local tissue reactions. An understanding of the origin of metal ions is really important in order to design alloys for reduced ion release. Reciprocating pin-on-plate wear tester is a standard instrument to assess the interaction of corrosion and wear. However, more realistic hip simulator can provide a better understanding of tribocorrosion process for hip implants. It is very important to instrument the conventional hip simulator to enable electrochemical measurements. In this study, simple reciprocating pin-on-plate wear tests and hip simulator tests were compared. It was found that metal ions originated from two sources: (a) a depassivation of the contacting surfaces due to tribology (rubbing) and (b) corrosion of nano-sized wear particles generated from the contacting surfaces. Copyright © 2012 Elsevier Ltd. All rights reserved.

  18. Design, development, and evaluation of a second generation interactive Simulator for Engineering Ethics Education (SEEE2).

    Science.gov (United States)

    Alfred, Michael; Chung, Christopher A

    2012-12-01

    This paper describes a second generation Simulator for Engineering Ethics Education. Details describing the first generation activities of this overall effort are published in Chung and Alfred (Sci Eng Ethics 15:189-199, 2009). The second generation research effort represents a major development in the interactive simulator educational approach. As with the first generation effort, the simulator places students in first person perspective scenarios involving different types of ethical situations. Students must still gather data, assess the situation, and make decisions. The approach still requires students to develop their own ability to identify and respond to ethical engineering situations. However, were as, the generation one effort involved the use of a dogmatic model based on National Society of Professional Engineers' Code of Ethics, the new generation two model is based on a mathematical model of the actual experiences of engineers involved in ethical situations. This approach also allows the use of feedback in the form of decision effectiveness and professional career impact. Statistical comparisons indicate a 59 percent increase in overall knowledge and a 19 percent improvement in teaching effectiveness over an Internet Engineering Ethics resource based approach.

  19. A simulation model for methane emissions from landfills with interaction of vegetation and cover soil.

    Science.gov (United States)

    Bian, Rongxing; Xin, Danhui; Chai, Xiaoli

    2018-01-01

    Global climate change and ecological problems brought about by greenhouse gas effect have become a severe threat to humanity in the 21st century. Vegetation plays an important role in methane (CH 4 ) transport, oxidation and emissions from municipal solid waste (MSW) landfills as it modifies the physical and chemical properties of the cover soil, and transports CH 4 to the atmosphere directly via their conduits, which are mainly aerenchymatous structures. In this study, a novel 2-D simulation CH 4 emission model was established, based on an interactive mechanism of cover soil and vegetation, to model CH 4 transport, oxidation and emissions in landfill cover soil. Results of the simulation model showed that the distribution of CH 4 concentration and emission fluxes displayed a significant difference between vegetated and non-vegetated areas. CH 4 emission flux was 1-2 orders of magnitude higher than bare areas in simulation conditions. Vegetation play a negative role in CH 4 emissions from landfill cover soil due to the strong CH 4 transport capacity even though vegetation also promotes CH 4 oxidation via changing properties of cover soil and emitting O 2 via root system. The model will be proposed to allow decision makers to reconsider the actual CH 4 emission from vegetated and non-vegetated covered landfills. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Refinement of Monte Carlo simulations of electron-specimen interaction in low-voltage SEM

    International Nuclear Information System (INIS)

    Kieft, Erik; Bosch, Eric

    2008-01-01

    A Monte Carlo tool is presented for the simulation of secondary electron (SE) emission in a scanning electron microscope (SEM). The tool is based on the Geant4 platform of CERN. The modularity of this platform makes it comparatively easy to add and test individual physical models. Our aim has been to develop a flexible and generally applicable tool, while at the same time including a good description of low-energy (<50 eV) interactions of electrons with matter. To this end we have combined Mott cross-sections with phonon-scattering based cross-sections for the elastic scattering of electrons, and we have adopted a dielectric function theory approach for inelastic scattering and generation of SEs. A detailed model of the electromagnetic fields from an actual SEM column has been included in the tool for ray tracing of secondary and backscattered electrons. Our models have been validated against experimental results through comparison of the simulation results with experimental yields, SE spectra and SEM images. It is demonstrated that the resulting simulation package is capable of quantitatively predicting experimental SEM images and is an important tool in building a deeper understanding of SEM imaging.

  1. New electromagnetic particle simulation code for the analysis of spacecraft-plasma interactions

    International Nuclear Information System (INIS)

    Miyake, Yohei; Usui, Hideyuki

    2009-01-01

    A novel particle simulation code, the electromagnetic spacecraft environment simulator (EMSES), has been developed for the self-consistent analysis of spacecraft-plasma interactions on the full electromagnetic (EM) basis. EMSES includes several boundary treatments carefully coded for both longitudinal and transverse electric fields to satisfy perfect conductive surface conditions. For the longitudinal component, the following are considered: (1) the surface charge accumulation caused by impinging or emitted particles and (2) the surface charge redistribution, such that the surface becomes an equipotential. For item (1), a special treatment has been adopted for the current density calculated around the spacecraft surface, so that the charge accumulation occurs exactly on the surface. As a result, (1) is realized automatically in the updates of the charge density and the electric field through the current density. Item (2) is achieved by applying the capacity matrix method. Meanwhile, the transverse electric field is simply set to zero for components defined inside and tangential to the spacecraft surfaces. This paper also presents the validation of EMSES by performing test simulations for spacecraft charging and peculiar EM wave modes in a plasma sheath.

  2. Compact X-ray sources. Simulating the electron/strong laser interaction

    Energy Technology Data Exchange (ETDEWEB)

    Hartin, Anthony [DESY, CFEL, Hamburg (Germany)

    2016-07-01

    The collision of an intense laser with an electron bunch can be used to produce X-rays via the inverse Compton scattering (ICS) mechanism. The ICS can be simulated via either a classical theory in which electrons and photons are treated in terms of classical electromagnetic waves - or a quantum theory in which charged particles interact with strong electromagnetic fields. The laser intensity used in a practical ICS collision is likely to be at such a level that quantum effects may be significant and the use of quantum theory may become a necessity. A simulation study is presented here comparing the classical and quantum approaches to the ICS. A custom particle-in-cell (PIC) software code, with photon generation by monte carlo of the exact quantum transition probability is used to simulate the quantum treatment. Peak resonant energies and the angular distribution of the X-rays are obtained and compared with those predicted by the classical theory. The conditions under which significant differences between the two theories emerges is obtained.

  3. Exponentially more precise quantum simulation of fermions in the configuration interaction representation

    Science.gov (United States)

    Babbush, Ryan; Berry, Dominic W.; Sanders, Yuval R.; Kivlichan, Ian D.; Scherer, Artur; Wei, Annie Y.; Love, Peter J.; Aspuru-Guzik, Alán

    2018-01-01

    We present a quantum algorithm for the simulation of molecular systems that is asymptotically more efficient than all previous algorithms in the literature in terms of the main problem parameters. As in Babbush et al (2016 New Journal of Physics 18, 033032), we employ a recently developed technique for simulating Hamiltonian evolution using a truncated Taylor series to obtain logarithmic scaling with the inverse of the desired precision. The algorithm of this paper involves simulation under an oracle for the sparse, first-quantized representation of the molecular Hamiltonian known as the configuration interaction (CI) matrix. We construct and query the CI matrix oracle to allow for on-the-fly computation of molecular integrals in a way that is exponentially more efficient than classical numerical methods. Whereas second-quantized representations of the wavefunction require \\widetilde{{ O }}(N) qubits, where N is the number of single-particle spin-orbitals, the CI matrix representation requires \\widetilde{{ O }}(η ) qubits, where η \\ll N is the number of electrons in the molecule of interest. We show that the gate count of our algorithm scales at most as \\widetilde{{ O }}({η }2{N}3t).

  4. Simulation study on characteristics of long-range interaction in randomly asymmetric exclusion process

    Science.gov (United States)

    Zhao, Shi-Bo; Liu, Ming-Zhe; Yang, Lan-Ying

    2015-04-01

    In this paper we investigate the dynamics of an asymmetric exclusion process on a one-dimensional lattice with long-range hopping and random update via Monte Carlo simulations theoretically. Particles in the model will firstly try to hop over successive unoccupied sites with a probability q, which is different from previous exclusion process models. The probability q may represent the random access of particles. Numerical simulations for stationary particle currents, density profiles, and phase diagrams are obtained. There are three possible stationary phases: the low density (LD) phase, high density (HD) phase, and maximal current (MC) in the system, respectively. Interestingly, bulk density in the LD phase tends to zero, while the MC phase is governed by α, β, and q. The HD phase is nearly the same as the normal TASEP, determined by exit rate β. Theoretical analysis is in good agreement with simulation results. The proposed model may provide a better understanding of random interaction dynamics in complex systems. Project supported by the National Natural Science Foundation of China (Grant Nos. 41274109 and 11104022), the Fund for Sichuan Youth Science and Technology Innovation Research Team (Grant No. 2011JTD0013), and the Creative Team Program of Chengdu University of Technology.

  5. Simulation of pellet-cladding thermomechanical interaction and fission gas release

    International Nuclear Information System (INIS)

    Denis, Alicia; Soba, Alejandro

    2003-01-01

    This paper summarizes the present status of a computer code that describes some of the main phenomena occurring in a nuclear fuel rod throughout its life. Temperature distribution, thermal expansion, elastic and plastic strains, creep, mechanical interaction between pellet and cladding, fission gas release, gas mixing, swelling, and densification are modeled. The modular structure of the code allows for the incorporation of models to simulate different phenomena and material properties. Collapsible rods can be also simulated. The code is bidimensional, assumes cylindrical symmetry for the rod and uses the finite element method to integrate the differential equations. The stress-strain and heat conduction problems are nonlinear due to plasticity and to the temperature dependence of the thermal conductivity. The fission gas inventory is calculated with a diffusion model, assuming spherical grains and using a one-dimensional finite element scheme. Pressure increase, swelling and densification are coupled with the stress field. Good results are obtained for the simulation of the irradiation tests of the first argentine prototypes of MOX fuels, where the bamboo effect is clearly observed, and of the FUMEX series for the fuel centerline temperature, the inside rod pressure and the fractional gas release.

  6. Spirit Scans Winter Haven

    Science.gov (United States)

    2006-01-01

    At least three different kinds of rocks await scientific analysis at the place where NASA's Mars Exploration Rover Spirit will likely spend several months of Martian winter. They are visible in this picture, which the panoramic camera on Spirit acquired during the rover's 809th sol, or Martian day, of exploring Mars (April 12, 2006). Paper-thin layers of light-toned, jagged-edged rocks protrude horizontally from beneath small sand drifts; a light gray rock with smooth, rounded edges sits atop the sand drifts; and several dark gray to black, angular rocks with vesicles (small holes) typical of hardened lava lie scattered across the sand. This view is an approximately true-color rendering that combines images taken through the panoramic camera's 753-nanometer, 535-nanometer, and 432-nanometer filters.

  7. Winter fuels report

    International Nuclear Information System (INIS)

    1995-01-01

    The Winter Fuels Report is intended to provide concise, timely information to the industry, the press, policymakers, consumers, analysts, and State and local governments on the following topics: distillate fuel oil net production, imports and stocks on a US level and for all Petroleum Administration for Defense Districts (PADD) and product supplied on a US level; propane net production, imports and stocks on a US level and for PADD's I, II, and III; natural gas supply and disposition and underground storage for the US and consumption for all PADD's, as well as selected National average prices; residential and wholesale pricing data for heating oil and propane for those States participating in the joint Energy Information Administration (EIA)/State Heating Oil and Propane Program; crude oil and petroleum price comparisons for the US and selected cities; and a 6-10 day, 30-Day, and 90-Day outlook for temperature and precipitation and US total heating degree-days by city

  8. Winter fuels report

    Energy Technology Data Exchange (ETDEWEB)

    1990-11-29

    The Winter Fuels Report is intended to provide concise, timely information to the industry, the press, policymakers, consumers, analysts, and state and local governments on the following topics: distillate fuel oil net production, imports and stocks for all PADD's and product supplied on a US level; propane net product supplied on a US level; propane net production, imports and stocks for Petroleum Administration for Defense Districts (PADD) I, II, and III; natural gas supply and disposition and underground storage for the United States and consumption for all PADD's; residential and wholesale pricing data for propane and heating oil for those states participating in the joint Energy Information Administration (EIA)/State Heating Oil and Propane Program; crude oil and petroleum price comparisons for the United States and selected cities; and US total heating degree-days by city. 27 figs, 12 tabs.

  9. Regimes of seasonal air-sea interaction and implications for performance of forced simulations

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Renguang [Center for Ocean-Land-Atmosphere Studies, Calverton, MD (United States); Kirtman, Ben P. [Center for Ocean-Land-Atmosphere Studies, Calverton, MD (United States); George Mason University, School of Computational Sciences, Fairfax, VA (United States)

    2007-09-15

    Sea surface temperature (SST) anomalies can induce anomalous convection through surface evaporation and low-level moisture convergence. This SST forcing of the atmosphere is indicated in a positive local rainfall-SST correlation. Anomalous convection can feedback on SST through cloud-radiation and wind-evaporation effects and wind-induced oceanic mixing and upwelling. These atmospheric feedbacks are reflected in a negative local rainfall-SST tendency correlation. As such, the simultaneous rainfall-SST and rainfall-SST tendency correlations can indicate the nature of local air-sea interactions. Based on the magnitude of simultaneous rainfall-SST and rainfall-SST tendency correlations, the present study identifies three distinct regimes of local air-sea interactions. The relative importance of SST forcing and atmospheric forcing differs in these regimes. In the equatorial central-eastern Pacific and, to a smaller degree, in the western equatorial Indian Ocean, SST forcing dominates throughout the year and the surface heat flux acts mainly as a damping term. In the tropical Indo-western Pacific Ocean regions, SST forcing and atmospheric forcing dominate alternatively in different seasons. Atmospheric forcing dominates in the local warm/rainy season. SST forcing dominates with a positive wind-evaporation feedback during the transition to the cold/dry season. SST forcing also dominates during the transition to the warm/rainy season but with a negative cloud-radiation feedback. The performance of atmospheric general circulation model simulations forced by observed SST is closely linked to the regime of air-sea interaction. The forced simulations have good performance when SST forcing dominates. The performance is low or poor when atmospheric forcing dominates. (orig.)

  10. Mechanism of microRNA-target interaction: molecular dynamics simulations and thermodynamics analysis.

    Directory of Open Access Journals (Sweden)

    Yonghua Wang

    Full Text Available MicroRNAs (miRNAs are endogenously produced approximately 21-nt riboregulators that associate with Argonaute (Ago proteins to direct mRNA cleavage or repress the translation of complementary RNAs. Capturing the molecular mechanisms of miRNA interacting with its target will not only reinforce the understanding of underlying RNA interference but also fuel the design of more effective small-interfering RNA strands. To address this, in the present work the RNA-bound (Ago-miRNA, Ago-miRNA-target and RNA-free Ago forms were analyzed by performing both molecular dynamics simulations and thermodynamic analysis. Based on the principal component analysis results of the simulation trajectories as well as the correlation analysis in fluctuations of residues, we discover that: 1 three important (PAZ, Mid and PIWI domains exist in Argonaute which define the global dynamics of the protein; 2 the interdomain correlated movements are so crucial for the interaction of Ago-RNAs that they not only facilitate the relaxation of the interactions between residues surrounding the RNA binding channel but also induce certain conformational changes; and 3 it is just these conformational changes that expand the cavity of the active site and open putative pathways for both the substrate uptake and product release. In addition, by thermodynamic analysis we also discover that for both the guide RNA 5'-end recognition and the facilitated site-specific cleavage of the target, the presence of two metal ions (of Mg(2+ plays a predominant role, and this conclusion is consistent with the observed enzyme catalytic cleavage activity in the ternary complex (Ago-miRNA-mRNA. Our results find that it is the set of arginine amino acids concentrated in the nucleotide-binding channel in Ago, instead of the conventionally-deemed seed base-paring, that makes greater contributions in stabilizing the binding of the nucleic acids to Ago.

  11. Photon dose estimation from ultraintense laser–solid interactions and shielding calculation with Monte Carlo simulation

    International Nuclear Information System (INIS)

    Yang, Bo; Qiu, Rui; Li, JunLi; Lu, Wei; Wu, Zhen; Li, Chunyan

    2017-01-01

    When a strong laser beam irradiates a solid target, a hot plasma is produced and high-energy electrons are usually generated (the so-called “hot electrons”). These energetic electrons subsequently generate hard X-rays in the solid target through the Bremsstrahlung process. To date, only limited studies have been conducted on this laser-induced radiological protection issue. In this study, extensive literature reviews on the physics and properties of hot electrons have been conducted. On the basis of these information, the photon dose generated by the interaction between hot electrons and a solid target was simulated with the Monte Carlo code FLUKA. With some reasonable assumptions, the calculated dose can be regarded as the upper boundary of the experimental results over the laser intensity ranging from 10 19 to 10 21 W/cm 2 . Furthermore, an equation to estimate the photon dose generated from ultraintense laser–solid interactions based on the normalized laser intensity is derived. The shielding effects of common materials including concrete and lead were also studied for the laser-driven X-ray source. The dose transmission curves and tenth-value layers (TVLs) in concrete and lead were calculated through Monte Carlo simulations. These results could be used to perform a preliminary and fast radiation safety assessment for the X-rays generated from ultraintense laser–solid interactions. - Highlights: • The laser–driven X-ray ionizing radiation source was analyzed in this study. • An equation to estimate the photon dose based on the laser intensity is given. • The shielding effects of concrete and lead were studied for this new X-ray source. • The aim of this study is to analyze and mitigate the laser–driven X-ray hazard.

  12. Mechanism of microRNA-target interaction: molecular dynamics simulations and thermodynamics analysis.

    Science.gov (United States)

    Wang, Yonghua; Li, Yan; Ma, Zhi; Yang, Wei; Ai, Chunzhi

    2010-07-29

    MicroRNAs (miRNAs) are endogenously produced approximately 21-nt riboregulators that associate with Argonaute (Ago) proteins to direct mRNA cleavage or repress the translation of complementary RNAs. Capturing the molecular mechanisms of miRNA interacting with its target will not only reinforce the understanding of underlying RNA interference but also fuel the design of more effective small-interfering RNA strands. To address this, in the present work the RNA-bound (Ago-miRNA, Ago-miRNA-target) and RNA-free Ago forms were analyzed by performing both molecular dynamics simulations and thermodynamic analysis. Based on the principal component analysis results of the simulation trajectories as well as the correlation analysis in fluctuations of residues, we discover that: 1) three important (PAZ, Mid and PIWI) domains exist in Argonaute which define the global dynamics of the protein; 2) the interdomain correlated movements are so crucial for the interaction of Ago-RNAs that they not only facilitate the relaxation of the interactions between residues surrounding the RNA binding channel but also induce certain conformational changes; and 3) it is just these conformational changes that expand the cavity of the active site and open putative pathways for both the substrate uptake and product release. In addition, by thermodynamic analysis we also discover that for both the guide RNA 5'-end recognition and the facilitated site-specific cleavage of the target, the presence of two metal ions (of Mg(2+)) plays a predominant role, and this conclusion is consistent with the observed enzyme catalytic cleavage activity in the ternary complex (Ago-miRNA-mRNA). Our results find that it is the set of arginine amino acids concentrated in the nucleotide-binding channel in Ago, instead of the conventionally-deemed seed base-paring, that makes greater contributions in stabilizing the binding of the nucleic acids to Ago.

  13. Interactive visualization system to analyze corrugated millimeter-waveguide component of ECH in nuclear fusion with FDTD simulation

    International Nuclear Information System (INIS)

    Kashima, N; Nakamura, H; Kubo, S; Tamura, Y; Ito, A M

    2014-01-01

    We have simulated distribution of electromagnetic waves through the system composed of miter bends by Finite-Difference Time-Domain (FDTD) simulation. We develop the interactive visualization system using a new interactive GUI system which is composed of the virtual reality system and android tablet to analyze the FDTD simulation. The effect of the waveguide system with grooves have been investigated to quantitatively by visualization system. Comparing waveguide system with grooves and without grooves, grooves have been confirmed to suppress the surface current at the metal surface. The surface current at complex shape such as the miter bend have been investigated

  14. Interactive NMR: A Simulation Based Teaching Tool for Fundamentals to Applications with Tangible Analogies

    Science.gov (United States)

    Griesse-Nascimento, Sarah; Bridger, Joshua; Brown, Keith; Westervelt, Robert

    2011-03-01

    Interactive computer simulations increase students' understanding of difficult concepts and their ability to explain complex ideas. We created a module of eight interactive programs and accompanying lesson plans for teaching the fundamental concepts of Nuclear Magnetic Resonance (NMR) and Magnetic Resonance Imaging (MRI) that we call interactive NMR (iNMR). We begin with an analogy between nuclear spins and metronomes to start to build intuition about the dynamics of spins in a magnetic field. We continue to explain T1, T2, and pulse sequences with the metronome analogy. The final three programs are used to introduce and explain the Magnetic Resonance Switch, a recent diagnostic technique based on NMR. A modern relevant application is useful to generate interest in the topic and confidence in the students' ability to apply their knowledge. The iNMR module was incorporated into a high school AP physics class. In a preliminary evaluation of implementation, students expressed enthusiasm and demonstrated enhanced understanding of the material relative to the previous year. Funded by NSF PHY-0646094 grant.

  15. An interactive system for creating object models from range data based on simulated annealing

    International Nuclear Information System (INIS)

    Hoff, W.A.; Hood, F.W.; King, R.H.

    1997-01-01

    In hazardous applications such as remediation of buried waste and dismantlement of radioactive facilities, robots are an attractive solution. Sensing to recognize and locate objects is a critical need for robotic operations in unstructured environments. An accurate 3-D model of objects in the scene is necessary for efficient high level control of robots. Drawing upon concepts from supervisory control, the authors have developed an interactive system for creating object models from range data, based on simulated annealing. Site modeling is a task that is typically performed using purely manual or autonomous techniques, each of which has inherent strengths and weaknesses. However, an interactive modeling system combines the advantages of both manual and autonomous methods, to create a system that has high operator productivity as well as high flexibility and robustness. The system is unique in that it can work with very sparse range data, tolerate occlusions, and tolerate cluttered scenes. The authors have performed an informal evaluation with four operators on 16 different scenes, and have shown that the interactive system is superior to either manual or automatic methods in terms of task time and accuracy

  16. Numerical Simulations for Nonlinear Waves Interaction with Multiple Perforated Quasi-Ellipse Caissons

    Directory of Open Access Journals (Sweden)

    Xiaozhong Ren

    2015-01-01

    Full Text Available A three-dimensional numerical flume is developed to study cnoidal wave interaction with multiple arranged perforated quasi-ellipse caissons. The continuity equation and the Navier-Stokes equations are used as the governing equation, and the VOF method is adopted to capture the free surface elevation. The equations are discretized on staggered cells and then solved using a finite difference method. The generation and propagation of cnoidal waves in the numerical flume are tested first. And the ability of the present model to simulate interactions between waves and structures is verified by known experimental results. Then cnoidal waves with varying incident wave height and period are generated and interact with multiple quasi-ellipse caissons with and without perforation. It is found that the perforation plays an effective role in reducing wave runup/rundown and wave forces on the caissons. The wave forces on caissons reduce with the decreasing incident wave period. The influence of the transverse distance of multiple caissons on wave forces is also investigated. A closer transverse distance between caissons can produce larger wave forces. But when relative adjacent distance L/D (L is the transverse distance and D is the width of the quasi-ellipse caisson is larger than 3, the effect of adjacent distance is limited.

  17. Long-range beam-beam interactions in the Tevatron: Comparing simulation to tune shift data

    International Nuclear Information System (INIS)

    Saritepe, S.; Michelotti, L.; Peggs, S.

    1990-07-01

    Fermilab upgrade plans for the collider operation include a separation scheme in the Tevatron, in which protons and antiprotons are placed on separate helical orbits. The average separation distance between the closed orbits will be 5σ (σ of the proton bunch) except at the interaction regions, B0 and D0, where they collide head-on. The maximum beam-beam total tune shift in the Tevatron is approximately 0.024 (the workable tune space between 5th and 7th order resonances), which was reached in the 1988--1989 collider tun. Helical separation scheme allows us to increase the luminosity by reducing the total beam-beam tune shift. The number of bunches per beam will be 6 in the 1991 collider tun, to be increased to 36 in the following collider runs. To test the viability of this scenario, helical orbit studies are being conducted. The most recent studies concentrated on the injection of 36 proton bunches, procedures related to opening and closing of the helix, the feed-down circuits and the beam-beam interaction. In this paper, we present the results of the beam-beam interaction studies only. Our emphasis is on the tune shift measurements and the comparison to simulation. 4 refs., 9 figs., 2 tabs

  18. Experimental simulation of magma-carbonate interaction beneath Mt. Vesuvius, Italy

    Science.gov (United States)

    Jolis, E. M.; Freda, C.; Troll, V. R.; Deegan, F. M.; Blythe, L. S.; McLeod, C. L.; Davidson, J. P.

    2013-11-01

    We simulated the process of magma-carbonate interaction beneath Mt. Vesuvius in short duration piston-cylinder experiments under controlled magmatic conditions (from 0 to 300 s at 0.5 GPa and 1,200 °C), using a Vesuvius shoshonite composition and upper crustal limestone and dolostone as starting materials. Backscattered electron images and chemical analysis (major and trace elements and Sr isotopes) of sequential experimental products allow us to identify the textural and chemical evolution of carbonated products during the assimilation process. We demonstrate that melt-carbonate interaction can be extremely fast (minutes), and results in dynamic contamination of the host melt with respect to Ca, Mg and 87Sr/86Sr, coupled with intense CO2 vesiculation at the melt-carbonate interface. Binary mixing between carbonate and uncontaminated melt cannot explain the geochemical variations of the experimental charges in full and convection and diffusion likely also operated in the charges. Physical mixing and mingling driven by exsolving volatiles seems to be a key process to promote melt homogenisation. Our results reinforce hypotheses that magma-carbonate interaction is a relevant and ongoing process at Mt. Vesuvius and one that may operate not only on a geological, but on a human timescale.

  19. Interactive Simulation and Visualization of Lamb Wave Propagation in Isotropic and Anisotropic Structures

    International Nuclear Information System (INIS)

    Moll, J; Schulte, R T; Fritzen, C-P; Rezk-Salama, C; Klinkert, T; Kolb, A

    2011-01-01

    Structural health monitoring systems allow a continuous surveillance of the structural integrity of operational systems. As a result, it is possible to reduce time and costs for maintenance without decreasing the level of safety. In this paper, an integrated simulation and visualization environment is presented that enables a detailed study of Lamb wave propagation in isotropic and anisotropic materials. Thus, valuable information about the nature of Lamb wave propagation and its interaction with structural defects become available. The well-known spectral finite element method is implemented to enable a time-efficient calculation of the wave propagation problem. The results are displayed in an interactive visualization framework accounting for the human perception that is much more sensitive to motion than to changes in color. In addition, measurements have been conducted experimentally to record the full out-of-plane wave-field using a Laser-Doppler vibrometry setup. An aluminum structure with two synthetic cuts has been investigated, where the elongated defects have a different orientation with respect to the piezoelectric actuator. The resulting wave-field is also displayed interactively showing that the scattered wave-field at the defect is highly directional.

  20. Earthquake simulation, actual earthquake monitoring and analytical methods for soil-structure interaction investigation

    Energy Technology Data Exchange (ETDEWEB)

    Tang, H T [Seismic Center, Electric Power Research Institute, Palo Alto, CA (United States)

    1988-07-01

    Approaches for conducting in-situ soil-structure interaction experiments are discussed. High explosives detonated under the ground can generate strong ground motion to induce soil-structure interaction (SSI). The explosive induced data are useful in studying the dynamic characteristics of the soil-structure system associated with the inertial aspect of the SSI problem. The plane waves generated by the explosives cannot adequately address the kinematic interaction associated with actual earthquakes because of he difference in wave fields and their effects. Earthquake monitoring is ideal for obtaining SSI data that can address all aspects of the SSI problem. The only limitation is the level of excitation that can be obtained. Neither the simulated earthquake experiments nor the earthquake monitoring experiments can have exact similitude if reduced scale test structures are used. If gravity effects are small, reasonable correlations between the scaled model and the prototype can be obtained provided that input motion can be scaled appropriately. The key product of the in-situ experiments is the data base that can be used to qualify analytical methods for prototypical applications. (author)